Cyme equipment reference manual

November 2010
CYME 5.02
Equipment
Reference Manual

© Copyright CYME International T&D Inc.
All Rights Reserved
No part of this publication may be reproduced, or transmitted in any form
or by any means without the written permission of CYME International T&D.
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CYME International T&D Inc.
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Canada
Tel.: (450) 461-3655
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mentioned in this document are the trademarks or trade names of the respective owners.

CYME 5.02 – Equipment Reference Manual
TABLE OF CONTENTS 5
Table of Contents
Chapter 1 Introduction.................................................................................................1
Chapter 2 Properties and Settings .............................................................................3
2.1 Overview of the Equipment Properties.........................................................3
2.1.1 Common Window Elements.............................................................3
2.2 Overview of the Equipment Settings ............................................................8
2.2.1 Common Window Elements.............................................................8
Chapter 3 Sources......................................................................................................11
3.1 Source Properties.......................................................................................11
3.1.1 Source Equivalent Impedances .....................................................12
Chapter 4 Regulators .................................................................................................15
4.1 Regulator Properties...................................................................................15
4.2 Regulator Settings ......................................................................................16
4.3 Regulator Control........................................................................................17
4.4 Regulator Meter Settings............................................................................19
Chapter 5 Transformers.............................................................................................23
5.1 Connection and Phase Shift Symbols ........................................................23
5.2 Transformer – Two Winding .......................................................................24
5.2.1 Two-winding Transformer Properties.............................................24
5.2.2 Two-winding Transformer Settings ................................................26
5.2.3 Load Tap Changer Settings ...........................................................27
5.2.4 Transformer Meter Settings ...........................................................28
5.2.5 By Phase Settings..........................................................................30
5.2.6 Single-phase Two-wire Configurations ..........................................30
5.2.7 Three-phase Configurations ..........................................................32
5.3 Two-winding Auto-transformer ...................................................................34
5.3.1 Two-winding Auto-transformer Properties .....................................34
5.3.2 Two-winding Auto-transformer Settings.........................................36
5.3.3 Auto-transformer Meter Settings....................................................37
5.4 Transformer – Three-winding .....................................................................39
5.4.1 Three-winding Transformer Properties ..........................................39
5.4.2 Three-winding Transformers Settings............................................41
5.4.3 First / Second Load Tap Changer..................................................42
5.5 Three-winding Auto-transformer.................................................................43
5.5.1 Three-winding Auto-transformer Properties...................................43
5.5.2 Three-winding Auto-transformers Settings ....................................45
5.5.3 First / Second Load Tap Changer..................................................46
5.6 Grounding Transformer ..............................................................................47
5.6.1 Grounding Transformer Properties ................................................47
5.6.2 Grounding Transformer Settings....................................................48
Chapter 6 Generators.................................................................................................49
6.1 Synchronous Generator .............................................................................49
6.1.1 Synchronous Generator Properties ...............................................49
6.1.2 Synchronous Generator Settings...................................................53
6.2 Induction Generator....................................................................................55
6.2.1 Induction Generator Properties......................................................55
6.2.2 Induction Generator Settings .........................................................59
6.3 Electronically Coupled Generator...............................................................60

6 TABLE OF CONTENTS
6.3.1 Electronically Coupled Generator Properties.................................60
6.3.2 Electronically Coupled Generator Settings ....................................61
Chapter 7 Motors........................................................................................................63
7.1 Induction Motor...........................................................................................63
7.1.1 Induction Motor Properties.............................................................63
7.1.2 Induction Motor Settings ................................................................68
7.1.3 Induction Motor Starting Assistance (LRA)....................................68
7.2 Synchronous Motor.....................................................................................70
7.2.1 Synchronous Motor Properties ......................................................70
7.2.2 Synchronous Motor Settings..........................................................73
7.2.3 Synchronous Motor Starting Assistance (LRA) Settings ...............74
Chapter 8 Static Var Compensators (SVC)..............................................................77
8.1 SVC Properties...........................................................................................77
8.2 SVC Settings ..............................................................................................78
Chapter 9 Wind Energy Conversion Systems .........................................................79
9.1 Wind Energy Conversion Systems Properties ...........................................79
9.1.1 Wind Turbine Tab...........................................................................79
9.1.2 Generator Tab................................................................................80
9.1.3 Generator Equivalent Circuit Tab...................................................81
9.2 Wind Energy Conversion System Settings.................................................83
9.3 Blade Pitch Control Settings.......................................................................84
9.4 Voltage Source Converter Settings ............................................................85
9.4.1 Full Converter Control Settings......................................................86
9.4.2 Doubly-Fed Converter Control Settings.........................................87
9.5 Wind Model Settings...................................................................................88
Chapter 10 Micro-turbines...........................................................................................89
10.1 Micro-turbine Properties .............................................................................90
10.2 Micro-turbine Settings.................................................................................91
Chapter 11 Photovoltaic ..............................................................................................93
11.1 Photovoltaic Properties...............................................................................94
11.2 Photovoltaic Settings ..................................................................................97
11.4 Insolation Model Settings .........................................................................100
Chapter 12 Solid Oxide Fuel Cells............................................................................101
12.1 Solid Oxide Fuel Cell Properties...............................................................102
12.2 Solid Oxide Fuel Cell Settings ..................................................................103
12.3 Voltage Source Converter Settings ..........................................................103
12.3.1 Full Converter Control Settings....................................................104
Chapter 13 Protective Devices..................................................................................105
13.1 Protective Devices Properties ..................................................................105
13.1.1 Fuse .............................................................................................106
13.1.2 LVCB ............................................................................................107
13.1.3 Recloser .......................................................................................108
13.1.4 Sectionalizer.................................................................................109
13.1.5 Switch...........................................................................................110
13.1.6 Breaker.........................................................................................111
13.1.7 Network Protector ........................................................................112
13.2 State Settings ...........................................................................................113

TABLE OF CONTENTS 7
13.3 Operation Settings....................................................................................114
13.4 Meter Settings...........................................................................................114
13.5 TCC Settings ............................................................................................116
13.6 Relay Settings...........................................................................................117
Chapter 14 Miscellaneous Equipment .....................................................................119
14.1 Miscellaneous Equipment Properties .......................................................119
14.2 Miscellaneous Equipment Settings...........................................................120
14.3 Miscellaneous Equipment Meter Settings ................................................120
Chapter 15 Lines and Cables ....................................................................................123
15.1 Overhead Line ..........................................................................................123
15.1.1 Overhead Line – Balanced...........................................................124
15.1.2 Overhead Line – Unbalanced ......................................................124
15.2 Cable.........................................................................................................125
15.2.1 General Tab .................................................................................125
15.2.2 Multi-wire concentric neutral cable...............................................126
15.2.3 Shielded cable..............................................................................128
15.2.4 Unshielded cable..........................................................................130
15.3 Conductor .................................................................................................131
15.3.1 General Tab .................................................................................131
15.4 Spacing.....................................................................................................133
15.5 Lines and Cables Settings........................................................................134
15.6 By Phase Configuration Settings..............................................................135
15.7 Spot Load and Distributed Load Settings.................................................136
Chapter 16 Shunt Capacitors....................................................................................141
16.1 Shunt Capacitor Properties ......................................................................141
16.2 Shunt Capacitor Settings..........................................................................142
Chapter 17 Shunt Reactors .......................................................................................145
17.1 Shunt Reactor Properties .........................................................................145
17.2 Shunt Reactor Settings.............................................................................146
Chapter 18 Series Capacitors ...................................................................................147
18.1 Series Capacitor Properties......................................................................147
18.2 Series Capacitor Settings .........................................................................148
18.3 Series Capacitor Meter Settings...............................................................148
Chapter 19 Series Reactors.......................................................................................151
19.1 Series Reactor Properties ........................................................................151
19.2 Series Reactor Settings............................................................................152
19.3 Series Reactor Meter Settings..................................................................152
Chapter 20 Network Equivalent ................................................................................155
20.1 Network Equivalent Settings.....................................................................155
20.2 Cumulated Information Settings ...............................................................156
Chapter 21 Harmonic Devices...................................................................................157
21.1 Frequency Source ....................................................................................157
21.1.1 Shunt Frequency Source Settings ...............................................158
21.2 Ideal Converter .........................................................................................159
21.2.1 Ideal Converter Settings...............................................................159
21.3 Non-Ideal Converter .................................................................................160
21.3.1 Non-Ideal Converter Settings.......................................................161
21.4 Arc Furnace ..............................................................................................162
21.4.1 Arc Furnace Settings....................................................................163
21.5 Filters ........................................................................................................164

8 TABLE OF CONTENTS
21.5.1 Single-Tuned Filter.......................................................................164
21.5.2 Single Tuned Filter Settings.........................................................165
21.5.3 Double-Tuned Filter .....................................................................166
21.5.4 Double Tuned Filter Settings........................................................168
21.5.5 High-Pass Filter............................................................................169
21.5.6 High Pass Filter Settings..............................................................169
21.5.7 C-Type Filter.................................................................................170
21.5.8 C-Type Filter Settings ..................................................................171
21.6 Branches...................................................................................................172
21.6.1 Shunt RLC Branch Settings .........................................................172
21.6.2 Shunt Parallel RLC Branch Settings ............................................172
21.6.3 Shunt Frequency Dependent Branch Settings ............................173
21.6.4 Shunt Mutually Coupled Three-phase Branch Settings...............174
21.6.5 Series RLC Branch Settings ........................................................174
21.6.6 Series Parallel RLC Branch Settings ...........................................174
21.6.7 Series Frequency Dependent Branch Settings............................175
21.6.8 Series Mutually Coupled Three-phase Branch Settings..............175
Chapter 22 Model Libraries .......................................................................................177
22.1 Control Model Library ...............................................................................177
22.2 Wind Model Library...................................................................................177
22.3 Insolation Model Library ...........................................................................177
Chapter 23 Symbol Library........................................................................................179
Chapter 24 Instruments .............................................................................................181
24.1 Instruments Settings.................................................................................182
24.1.1 Current Transformer.....................................................................182
24.1.2 Over Current Relay ......................................................................183
24.1.3 Motor Relay..................................................................................185
24.1.4 Potential Transformer...................................................................187
24.1.5 Voltage Relay...............................................................................188
24.1.6 Frequency Relay ..........................................................................190
24.1.7 Load Shedding Relay Control ......................................................192
24.1.8 Generic Control ............................................................................193

CHAPTER 1 – INTRODUCTION 1
Chapter 1 Introduction
The equipments database contains a set of generic equipment models to be used on the
distribution network. Once placed on a network section, the generic equipment may acquire new
properties and the original values of some of its parameters can be modified according to the
control to be performed. Thus, by virtue of its position on the network and its parameters new
values, from “generic” the equipment becomes “specific”. Consequently, it will acquire a new
identity through the equipment Number.
It is really important to realize that the original values of the generic equipment do not
change in the equipment database tables. Instead, the new values (the changes made to the
original values (that we also call the Settings) are saved in the network database tables.
Changes to a generic equipment require necessarily that you invoke one of the Equipment menu
commands in order to access the relevant equipment properties dialog boxes. Other access
points to the equipments properties dialog boxes will authorize only to visualize the parameters’
values. The modification of specific equipment in the network always requires access to the
properties dialog box of the section containing the equipment in question.
In the following chapters, the display of an equipment property dialog box (for example a
regulator) will imply the use of the command Equipment > Regulator. The display of an
equipment settings dialog box (for example shunt capacitor settings) will imply access to the
Properties dialog box of the section containing the shunt capacitor in question. You may access
the section properties dialog box in many ways using the one-line diagram or the Explorer Bar;
refer to the CYME Reference Manual for more details.

CHAPTER 2 – PROPERTIES AND SETTINGS 3
Chapter 2 Properties and Settings
2.1 Overview of the Equipment Properties
Every piece of equipment connected to a section in a feeder (network) represents an
individual unit of a type defined in the equipment database. You may think of the Equipment
database as a warehouse, or catalog, where each type of transformer is described.
Selecting an equipment type from the Equipment menu will display the appropriate
equipment dialog box, listing all available variants defined under that particular type, where you
can add, edit or delete equipment in the active equipment database.
2.1.1 Common Window Elements
Equipment
List
(1)
Unique name of a variant of the equipment type. To edit an existing
variant, highlight its name in the Equipment List and then change
the data in the tabbed area of the dialog box.
If you click anywhere inside the Equipment List window, the
following menu will pop up.

4 CHAPTER 2 – PROPERTIES AND SETTINGS
Create Copy: To create a copy of the selected equipment. Pops up
the Equipment ID dialog box with the selected name highlighted to
allow you to enter a new name. The new name, if it is unique, will
be added to the list of available equipments.
Delete: To delete the selected equipment from the list.
Rename: Pops up the Equipment ID dialog box with the selected
name highlighted to allow you to enter a new name. This name, if it
is unique, will replace the old one in the list of available equipments.
After using the Compare With Library command (See List
Command buttons below), the menu may offer an additional item:
Update to Library Version.
If the data of an equipment taken from the library have been
modified, this command will allow you to revert to the original data.
Equipment whose data have changed will have a red dot placed
next to it. Equipment with exactly the same data as the reference in
the library will have a check mark next to it.
Filter
(2)
To find a component just by typing a series of characters that
appear in its identification name (example: typing “CU” in the filter
of the Cable database dialog box might bring all copper conductors
in the cable database).
Tabs
(3)
All equipments have the tabs General and Comments in common.
In some cases equipment may have additional tabs such as
Loading Limits, Reliability, Harmonic, and Equivalent circuit and so
on.
In general, the Comments tab contains a multiple lines editing field.
It allows entering a description or significant comments about the
equipment in question.
The Loading Limits tab will let you define capacity in kVA or
kVA/phase or MVA (for Summer, Winter, Summer Emergency and
Winter Emergency) used for overload detection. “Summer”,
“Winter”, “Summer Emergency” and “Winter Emergency” are labels
that are used to describe the rating values of these fields. To enter
the labels in question, go to File > Preferences, Text tab.
Choose which rating to use for overload detection via the Analysis
> Load Flow dialog box, Loading / Voltage Limits tab before, or
even after, running a Load Flow calculation.
Record
command
buttons
(4)
OK: Updates the Equipment database and exits the dialog box.
Cancel:Exits the dialog box without saving any of the work you did
since opening it.

Title bar
buttons
(5)
Contextual help. It will display relevant section of the help file.
Closes the dialog box dismissing all changes.
List command
buttons
(6)
Add: To add a new variant to an equipment type. Pops up the
Equipment ID dialog box with the selected name highlighted to
allow you to enter a new name. The new name, if it is unique, will
be added to the list of available equipments.
Copy: Pops up the Equipment ID dialog box with the
selected name highlighted to allow you to enter a new name. This
name, if it is unique, will replace the old one in the list of available
equipments.
Add From Library: To get equipment directly from the library.
The library is a file, provided by the software that contains
equipment from various manufacturers. Click on the command to
open the Library interface. This interface is almost the exact copy of
the equipment type selected. The main difference results from the
fact that you cannot modify any data.
In this dialog box, you may select equipment individually by clicking
inside the check box next to the equipment or you may use Select
All to select all elements in the list. As soon as an equipment is
selected, the Add button will be enabled. Click on it to add selected
equipment to your equipment list. Use Unselect All to clear all
selections.
The Add From Library command will function differently for fuses,
reclosers and LVCBs. For those cases, the dialog box displayed
will look like this:

Characteristics: This section’s parameters are the same found in
the Information group box of the previous dialog. Refer to the
fuse/recloser/LVCB dialog box for description.
ID Generation: This section is used to give an ID to the equipment
you are about to create. The field ID indicates the pattern the
generation process will use to generate the IDs. In the example
above, the ID content (MODEL_RATING) indicates that the ID will
be a concatenation of the Model field content COOPERD (without
the space), then “_” (Underscore character) ending with the Rating
field content 4D. Note that Model and Rating are indicated as keys
and consequently are shown in blue in the ID field contrary to other
pattern elements (like the underscore). You can select the number
of characters to use for keys (Model and Rating) during the
concatenation process. In so doing, remember that ID length
cannot exceed 32 characters. Note that if the contents of keys in
the pattern are set to (ALL) you can generate instantaneously the
whole range of possible IDs. You may create your own pattern but
you must make sure that the names generated will be unique
otherwise they will not be allowed.
Equipment to Add: When you click on the button, the
device or set of devices described in the Characteristics group
box will be added in the list under the name(s) generated according
to the pattern provided in the ID field.
To delete an item from this list, select it and then click on the Delete
key. Multiple deletions are also possible. Select the range of items
to delete and then click on the Delete key.
It is also possible to use the popup menu to rename or delete any
item in the list. Make a right-click on the item you want to rename or
delete in order to display the following menu. Then click on
Rename or Delete.

You can rename only one item at a time through the Equipment ID
dialog box that will open on selecting the Rename function. To
delete more than one item, first select the items and then make a
right-click anywhere within the list’s window to access the Delete
function.
Click on Add to transfer all elements from this list to the Equipment
List in the previous dialog.
Compare With Library: The program will go through the
equipment list comparing each equipment in the list to the same
equipment (if it exists) in the library. If the data is not the same, the
equipment whose data have changed will have a red dot placed
next to its name. Equipment with exactly the same data as the
reference in the library will be flagged with a check mark next to it.
Equipment not found in the library will not be flagged.

2.2 Overview of the Equipment Settings
The default properties for the devices, lines, etc. are set through the commands found
under the Equipment menu. Once a section is identified as a line or a cable, and when an
equipment is connected to a section, you can make adjustments to them “in the field”. These
adjustments are called “settings” and are comprised in the right hand portion of the Section
Properties dialog box.
Note: The data given in the settings pane of the Section Properties dialog box have
priority over the (default) data given when the equipment was originally defined
under the Equipment menu.
To modify the settings of a specific instance of a device, click on the elements in the
Devices list of the dialog box to select the target equipment’s layer, and sub-layers
(TCC Settings and or Meter Settings), and then modify the parameters in the Settings group box
according to your requirement.
2.2.1 Common Window Elements
All the section Properties dialog boxes contain a group box that is located at the upper
right hand section of the dialog box. You will notice that the name of that group box will change
depending on the element selected from the Devices list and its position on the section.
ID
or
Type
Applies the standard / global settings as defined in the Equipment
menu for each device type. You may select the exact device your
need from the ID drop-down list. For lines and cables, you make this
selection from the Type drop-down list.
Number When you create a new section, CYME will automatically fill this field
with the default section ID. You can control the section naming
mechanism by modifying the parameters in the group zone Default
Section ID of tab System Parameters from the dialog box
Preferences (File > Preferences). However, you may enter your own
unique identifier for the individual device.
Location The position of the equipment with reference to the section. Available
positions may be At From Node / At Middle / At To Node, or At From
Node / At To Node, depending on the type of equipment.
Status May be: Connected, Disconnected or Bypassed.
To consult the default parameters of the related equipment type.
To display the Failure History report related to the component.
Failure History data are used by the Reliability Assessment module of
CYME.

The bottom part of the right hand part contains the settings specific to each equipment.

CHAPTER 3 – SOURCES 11
Chapter 3 Sources
3.1 Source Properties
The source (source equivalent) is the starting point of a network. It represents the
impedance of the generation and transmission network. The following data is required to define a
source. Use this command to create, modify, or delete the list of sources in your database. This
chapter covers the General tab of the dialog box. Information about the Harmonic tab can be
found in the Harmonic Analysis Users Guide.
Nominal
Capacity
Nominal capacity in MVA used for overload detection.
Source
Equivalent
Voltage
Nominal kV line-to-line reference voltage.
Operating kV line-to-line operating voltage.
Note: The operating voltage of each instance of a
substation equivalent (source) can be
changed individually when creating the source
(Edit > Add Source, Source tab.
Phase Angle Angle of the desired voltage on Phase A.

12 CHAPTER 3 – SOURCES
Source
Equivalent
Impedances
Positive-sequence resistance and reactance, in Ohms at the
nominal voltage, or in per-unit on the system MVA base defined in
the File > System Parameters dialog box.
Zero-sequence resistance and reactance, in Ohms at the
nominal voltage, or in per-unit on the system MVA base defined in
the File > System Parameters dialog box.
Source
Configuration
Wye-Grounded or Delta. Note that the calculations and the
behavior of the network will take this data into account.
3.1.1 Source Equivalent Impedances
3.1.1.1 Calculate using short-circuit power
This option uses the short-circuit MVA to calculate the equivalent impedance of
the transmission network, including the substation.
Three phase
MVA
Is the magnitude of a 3-phase fault on the secondary side of the
substation transformer. It is computed from (current in kA) x (line-line
voltage in kV) x √3.
Single phase
MVA
Is the magnitude of a line-to-ground fault on the secondary side of
the substation transformer. CYME defines it the same way as three-
phase MVA.
Note: Do not enter single-phase MVA as (current in kA) x (line-
neutral voltage in kV).
Three phase
X/R
Is the positive sequence ratio (X1/R1) of the equivalent fault
impedance. It is computed from tan (angle) if necessary.
Single phase
X/R
Is the ratio (Xg/Rg), where:
Xg = X1 + X2 + X0 and Rg = R1 + R2 + R0.
Voltage Is the line-to-line voltage in kV at the substation transformer
secondary.

CHAPTER 3 – SOURCES 13
3.1.1.2 Calculate using source details
This option calculates the equivalent impedance from the sum of the impedances
of the substation transformer(s) and the transmission network. Refer to the diagram
below for a definition of the substation equipment and configuration.
Typical substation as understood by CYME
• Rsrc : total resistance of the transmission network in ohms.
• Xsrc : total reactance of the transmission network in ohms.
• XFO : Substation transformer.
• Xs : Fault-limiting reactance connected in the branch (optional).
• Xss : Fault-limiting reactance connected at the secondary bus (optional).
With this option, you begin by defining the primary side impedance (Rsrc, Xsrc)
and the (optional) secondary fault-limiting reactance (Xss).

14 CHAPTER 3 – SOURCES
Primary
Network
Equivalent
Offers two ways to define the primary side impedance:
Calculate using short-circuit power: enter the short-circuit
MVA and X/R ratio and line-to-line voltage (in kV) at the
primary side of the substation. Refer to 3.1.1.1 for a definition
of the short-circuit powers and X/R ratios.
Primary Impedances: enter the equivalent sequence
impedances (Z1, Z0) and the line-to-line voltage in kV at the
substation transformer secondary.
Secondary
fault-limiting
reactance (Xss)
Given in Ohms. It is optional. When a value of “0” is indicated,
then CYME considers there is none.
Transformers
Configuration Click on the arrow ( ) in order to select the connection type at
the primary and the secondary for all transformers.
Transformer
Branches
The substation consists of one or more "branches" each
containing a transformer and optional fault-limiting reactance (Xs).
You must define at least one branch in order to continue with the
calculation. You may create as many as 5 branches.
Click on the Add button to define a branch.
Status: Branch may be on ( ) or off ( ). Click on the check
box to toggle between on and off.
Branch ID: Select the cell with a single left-click and start typing
the ID. You may also double-click in the cell area to select the
original value and then start typing the new value.
Fault-limiting reactance (Xs): Enter the impedance, if there is
one. Select the cell with a single left-click and start typing the
impedance. You may also double-click in the cell area to select
the original value and then start typing the new value.
Transformer ID: Click on the arrow to select the desired
transformer from the list. Click on to display the parameters of
the one selected.
Click on the Remove button to delete the selected (highlighted)
branch.
OK CYME saves the changes and computes the total impedances
and writes them in the spaces provided in the initial dialog box.
Cancel CYME cancels all data modifications before returning to the initial
dialog box.

CHAPTER 4 – REGULATORS 15
Chapter 4 Regulators
4.1 Regulator Properties
Regulator Type Select single-phase or three-phase.
Nominal Rating In kVA / phase and Amps.
Rated Voltage Rated kV is line-to-neutral for Wye-ground connection, line-to-
line for open Delta.
Note: For the purpose of overload detection, the rated kVA will
be adjusted as a function of the actual regulation range
(See below). You can modify these default values via the
Analysis > Load Flow dialog box, Loading / Voltage
Limits tab. (see the CYME Basic Analyses Users Guide)
• Range: 10.0% -> Rating: 100 % of nominal
Maximum buck Maximum range for which the regulator can lower the voltage.
Maximum boost Maximum range for which the regulator can raise the voltage.
Note: To model an auto-booster with CYME, you can use a
regulator with maximum buck = 0% so that the
regulator can only raise the voltage.

16 CHAPTER 4 – REGULATORS
Number of taps Number of possible positions for the regulator, excluding the
nominal position.
Bandwidth Tolerance (± bandwidth / 2) on the voltage to be maintained by
the regulator. It is expressed on the voltage reference (e.g. 121 V
± 1V).
CT primary
rating
Primary current rating of the current transformer used to provide
a current source value for the line drop compensation and for
metering functions. For example, if the nameplate indicates a CT
ratio of 250/0.2, 250 has to be entered.
PT ratio Overall potential transformer ratio of the regulator.
Reversible If reverse power flow is allowed, activate the Reversible option.
If not, then CYME will prevent the opening or closing of regulator
that would lead to reverse power flow through the regulator.
4.2 Regulator Settings
Primary To indicate where the primary of the regulator is connected on
the section: “At From Node” or “At To Node”.
Phase shift Enabled only when the configuration Closed-Delta is selected,
the options are “Lagging” and “Leading”.
Configuration Is Wye-Gnd, Closed-Delta or Open-Delta for a single-phase
regulator. A three-phase regulator is either Wye-Gnd or Closed-
Delta.
Maximum Buck
Maximum Boost
Buck or Boost may be set to lesser values than what the
regulator is rated for, increasing its current/power rating.
Bandwidth Tolerance (± bandwidth / 2) on the voltage to be maintained by
the regulator. It is expressed on the voltage reference.

CT primary
rating
Primary current rating of the current transformer used to provide
a current source value for the line drop compensation and for
metering functions.
PT ratio Overall potential transformer ratio of the regulator.
The default voltage setting for regulators is set in the File > Preferences, Systems
Parameters tab dialog box. To ignore all regulators during a Capacitor Placement or Voltage
Drop, select the Analysis > Load Flow menu command and select the Controls tab.
4.3 Regulator Control
Operating
Mode
There are four methods to obtain the settings for the regulator.
• The first is to treat the regulator as a Fixed-tap auto-transformer.
• The second method is to set the regulator to control the voltage at
its own Regulator terminal.
• The third is to calculate the R-X settings to compensate for the
line impedance between the regulator and the load center where
the voltage is to be controlled.
• The fourth method is to simply specify the Load center where the
voltage is to be controlled by entering the section ID. CYME will
evaluate automatically the impedance equivalent of the line
between the regulator and the load center.
Depending on the option selected, the relevant fields of this dialog box
will be enabled or disabled.
At Node Name of the load point. Enabled when the “Load Center” operating
mode is selected. Location for which the regulator will control the
voltage.
First House
Protection
Enabled when the “Load Center” or “R-X Settings” operating mode is
selected. Voltage limits that the regulator must respect.

Reverse
Sensing
Mode
Bi-Directional
Operates in both directions. If the real component of the current is
above the threshold, the regulator operates in the forward direction. If
the real component of the current is below the threshold, it operates in
the reverse direction. When the current is within the threshold, the
control stays at the last tap position.
Co-generation
When reverse power is detected, the control sensing input voltage will
not reverse (always in forward direction) and the line drop
compensation settings will be altered to account for the change in
power flow direction.
Locked Forward
Always operates in the forward direction. When more than 2% reverse
current is detected, the control stays on the last tap position.
Locked Reverse
Always operates in the reverse direction. If more than 2% forward
current is detected, the control stays on the last tap position.
Neutral Idle
Only operates in the forward direction when the real component of the
current is above the threshold. When the real component of the
current is reverse and is below the threshold, the control will tap to the
neutral position (buck/boost within ±0.3%).
No Reverse
Always operate in the forward direction. When the real component of
the current is reverse (>0), the control stays at the last tap position.
Reverse Idle
Operates in the forward directions. When the real component of the
current is above the threshold, the regulator operates in the forward
direction. When the real component of the current is below the
threshold, it stays at the last tap position.
Reactive Bi-Directional
Operates in both directions depending on both the real and reactive
component of the current. When the reactive component of the current
in the reverse direction, it operates in the forward direction. When the
real component of the current in the forward direction is above the
threshold and that the reactive component is within the threshold, it
also operates in the forward direction.
When the reactive component of the current in the forward direction is
above the threshold, it operates in the reverse direction. When the real
component of the current in the forward direction is above the
threshold and that the reactive component of the current is within the
threshold, it also operates in the reverse direction.
Threshold Current threshold at which the control switches operation, either from
forward to reverse or vice-versa.
Status For a single-phase regulator, indication of the phase(s) on which the
regulator is installed. The user will have to enter the settings for all
phases selected.
For a 3-phase regulator, indication of the control phase. Only one
phase can be selected.

Tap If the option “Fixed Tap” is selected in the Operating Mode field, it is
the fixed tap position at which the regulator will be considered by
CYME. Otherwise, it is the present tap position of the regulator. During
any related load flow analysis, CYME will determine automatically the
tap position depending on the status of the network and update this
number.
FORWARD/
REVERSE
Depending on the Reverse Sensing Mode selected, the forward and
reverse settings will be enabled accordingly.
Voltage: Voltage to be maintained by the regulator.
Rset: Enabled when the “R-X Settings” option is selected, this is the
“R” setting of the regulator.
Xset: Enabled when the “R-X Settings” option is selected, this is the
“X” setting of the regulator.
Hint: If you already know the R-X Settings, simply select the R-X Settings option
and type the values in the appropriate spaces.
If you don’t know the R-X Settings, and want to use this control option, you
can use the following method:
• Under "Operating Mode/Mode", select "Load Center" from the pull
down menu.
• Click on the pull down menu of "At Node" to list all sections downstream
from the regulator. Click on the one whose voltage is to be regulated.
• Under "FORWARD/Voltage", enter the desired voltage (in terms of the
base voltage) at the regulated section. Do this for each phase selected.
• Under “First House Protection”, you can specify the High / Low voltage
limits.
• Click OK and run the Voltage Drop analysis. CYME will compute the R-
X settings and indicate them in the regulator/control dialog box.
• Return to this dialog box and change the “Operating Mode/Mode” to
“R-X Settings”.
Follow the same procedure for the reverse direction.
4.4 Regulator Meter Settings

New To enable the meter settings input.
Delete To dismiss the meter settings input.
Connected To deactivate or activate the meter.
Location To indicate on which side (Primary or Secondary) of the regulator
the meter is connected.
Type Available options are: kVA-PF, AMP-PF, kW-PF, kW-kVAR. The
demand data fields (kW, kVAR in the illustration above) will vary
depending on the type you select.
In a PF(%) data field, you may enter a leading power factor by
typing a negative value (e.g., -98.0).
Total To allow entering combined demand for all three phases. Instead
of having to enter values for all phases as indicated in the above
illustration, you will enter only one (Total) value.
To assign Allocation Factors and Power Factors for the
different consumer categories. See also Analysis > Load
Allocation.

To display a summary of the downstream load and capacitors, for
information. Use this information to help you enter relevant meter
data. You may filter the downstream information by customer
type.
See also Analysis > Load Allocation.
Accesses the optional Energy Profile Manager module and
displays the meter profile.

CHAPTER 5 – TRANSFORMERS 23
Chapter 5 Transformers
5.1 Connection and Phase Shift Symbols
The star, delta, or zigzag connection of a transformer is indicated by the capital letters Y,
D or Z for the primary-voltage winding, and by the small letters y, d or z for the secondary
(tertiary)-voltage winding. If the neutral point of a star-connected or zigzag-connected winding is
brought out, the indication is YN (yn) or ZN (zn) respectively. Open windings are indicated as O
(o). The winding connection letter for the secondary (tertiary)-voltage winding is immediately
followed by its phase shift « clock number »
The phase shift of a winding is the phase angle between the phasors representing the
voltages between the neutral point (real or imaginary) and the corresponding terminals of two
windings, with a balanced three-phase positive sequence voltage being applied to the primary-
terminals. The phasors are assumed to rotate in a counterclockwise direction. Using the primary-
voltage winding phasor as the reference, the displacement of the secondary (tertiary)-voltage
winding will be expressed, according to the convention, by the 'clock notation' hour. This is the
hour indicated by the secondary (tertiary)-voltage winding phasor when the primary-voltage
winding phasor is at 12 o'clock (rising numbers indicate increasing phase lag).
'Clock number' notation – two examples (IEC 600760-1©)
Example 1 – Symbol: Dyn11: A distribution transformer with high-voltage winding for 20 kV, delta-
connected (D). The low-voltage winding is 400 V star-connected (y)with neutral (n) brought out.
The LV winding lags the HV by 330° (11h).
Example 2 – Symbol: YNd5: A two-winding transformer with high-voltage winding for 123 kV,
star-connected (Y) with neutral (N) brought out. The low-voltage winding is 7.2 kV delta-
connected (d), lagging by 150° (5h).

24 CHAPTER 5 – TRANSFORMERS
5.2 Transformer – Two Winding
5.2.1 Two-winding Transformer Properties
Generally, these transformers are “in-line”, step-down power transformers. Customer
(i.e., load) transformers are generally not modeled explicitly.
5.2.1.1 General Tab
Transformer Type Three types are available: Single-phase, Three-phase Shell
and Three-phase core. The latter requires three sets of zero-
sequence values compared to one for the other two.
Nominal Rating Total kVA for 3-phase Type transformer or per phase for 1-
phase Type.
Primary Voltage
Secondary Voltage
kV line-to-line.
kV line-to-line. For any winding of a 1-phase transformer
which is connected line-to-ground, enter (line-ground voltage)
x √3.
No load losses kW Total for 3-phase and kW per Phase for 1-phase.
Insulation Type Select either Liquid-filled or Dry.

Sequence
Impedances
Positive-sequence Impedance Z1 in percent on transformer
kVA base, zero-sequence Impedance Z0 in percent on
transformer kVA base, positive sequence (X1/R1) and zero-
sequence (X0/R0) ratios.
If you click on the Default button, CYME will suggest typical
values for Z1, Z0 and X/R based on the kVA and primary
voltage.
In a three-phase core transformer, zero-sequence impedance
and ratio are required for the following combinations: primary-
secondary, primary-magnetizing, secondary-magnetizing.
Grounding
Impedances
Grounding resistance and reactance for the primary side and
grounding resistance and reactance for the secondary side.
Reversible If Reversible is not active, then you will be prevented from
closing any switch that would direct power flow from the
transformer secondary side to its primary side.
Configuration CYME supports the four practical configurations for a single-
phase transformer: See also section 5.2.5 By Phase Settings,
5.2.6 Single-phase Two-wire Configurations, and 5.2.7 Three-
phase Configurations.
Note: If you connect a 1-phase unit to a 2-phase or 3-phase section, identical
transformers will be installed in each phase.
5.2.1.2 Load Tap Changer (LTC) Tab
The data for the on-Load Tap Changer (LTC) should be set to zero unless the
transformer is equipped with such a device.
Bandwidth Is the tolerance on the voltage that the LTC must maintain; in percent
of the base voltage. (see 5.3.2 Two-winding Auto-transformer Settings)
Taps Is the number of discrete tap positions in the LTC.
Maximum /
Minimum
Range
Is the range of voltage boost/buck covered by the taps.

5.2.2 Two-winding Transformer Settings
Primary To indicate on which node the primary of the transformer is
connected.
Fault
Indicator
To indicate via a signal that the fault is located downstream of the
device. The Reliability Assessment Module (RAM) uses this
parameter. See the Reliability Analysis Users Guide.
Fixed Tap To enter primary and secondary taps setting of this particular
transformer, either to raise or lower the voltage.
Grounding
Impedances
To define the grounding impedance on both the primary and
secondary side.
Configuration To define the configuration of this particular transformer.
Protection Will open the TCC protection coordination dialog box for the
selected device, so that you may inspect and adjust its settings as
well as create a new “standard” setting.
Note: You do not need to have CYMTCC installed in order to
use this command. However, with CYMTCC, you will be
able to perform more extensive protection analyses.
System Base
Voltage
To define the primary and or secondary base voltage. Checkmark
User defined to enable the voltage field.

5.2.3 Load Tap Changer Settings
If you entered data for a Load Tap Changer when you created the transformer in the
equipment database, then the Load Tap Changer sub-layer will appear directly under the main
transformer layer. These are the same as defined for Regulators. Click on the sub-layer to set
the desired voltage, R-X settings or tap position.
Location To indicate that the Load Tap Changer is located on the Primary or
secondary side of the transformer.
Mode The different methods to obtain the settings for the transformer. See
Operating Mode in chapter 4.3 Regulator Control.
At Node Enabled when the mode “Load Center” is selected. Location for which
the LTC will control the voltage.
LDC
settings
R: Resistive voltage drop on the line between the transformer and
the load location.
X: Reactive voltage drop on the line between the transformer and
the load location.
They represent the voltage drop on the line when the line is carrying
CT-rated primary current.
Set Voltage These values are in percentage of the system base voltage at the
secondary of the transformer.
Use last
load flow
To consider the last position of tap after a load flow analysis when the
VCR was active.
Initial Enter the initial tap position if you are not using the “Use last load flow”
option.
Final Final tap position at the end of the simulation.
Buck/Boost Range of voltage covered.
Is slave When connected in parallel, checkmark this option to enter a Master Id
for the two-winding transformer.

Master Id When two transformers are connected in parallel, one of them may
be chosen as Master and the control settings (fixed-tap, terminal, load
center, R-X settings) defined for it. The other transformer may be
designated as Slave by:
1. Selecting the Is Slave option in the Parallel Operation group box
(see illustration above)
2. Specifying the Master transformer section ID
The Slave’s controls are locked with the Master control in a load flow
calculation
(e.g., Voltage Drop).
If you have the Transient Stability module installed, you will notice that the Load Tap
Changer item in the Devices tree list can be expanded to reveal the Stability Model settings
group box. This element is discussed in the Transient Stability Analysis Users Guide.
5.2.4 Transformer Meter Settings
Location To indicate on which side (Primary or Secondary) of the two-
winding transformer the meter is connected.
Diversity Calculates the diversity factors based on the demands of each of
the feeders and the transformer demand. The value calculated is
displayed in the Diversity field.

different consumer categories.
To display a summary of downstream load and capacitors, for
type.

5.2.5 By Phase Settings
The transformer by-phase settings dialog box is to model a configuration of single-phase
transformers of different ratings. It is also the only model that permits the modeling of center tap
connections. To add this type of transformer configuration in the network, click the Add button in
the Devices group box of the Section Properties dialog box and select the Transformer By-
Phase from the pop up menu.
If you need to model loads connected to a center tap, you need to define a transformer
by-phase upstream of the load and enable the phases where a center tap connection is present.
5.2.6 Single-phase Two-wire Configurations
CYME supports the four practical configurations for a single-phase transformer:
Ygrd - Ygrd Ygrd - D D - Ygrd D - D
• Ygrd (Wye-grounded) means “single-phase, two wires, grounded”.
• D (Delta) means “single-phase, two wires, ungrounded”.
Single-phase
Ygrd – Ygrd
• The primary of this transformer must be connected to a single-
phase section.
• Downstream sections are connected to the same phase as the
primary.
• The load configuration downstream from this transformer must be
set to Ygrd.

Single-phase
Ygrd – D
The secondary of this transformer is a two-wire ungrounded system
(single-phase Delta). CYME reports the current on one wire only
since the other carries the same current.
• The primary of this transformer must be connected to a single-
phase section.
• Downstream sections are connected to the same phase as the
primary.
set to Delta (D).
Single-phase
D – Ygrd
The primary of this transformer is connected between two phases
(AB, BC or CA).
• The primary of this transformer must be connected to a two-
phase section.
• Downstream sections and loads must be single-phase. See
table below.
set to Ygrd.
Primary phases Secondary phase Load phase
AB A A
BC B B
CA C C
Example: If the primary side is connected between phases A and B,
any load or section connected to the secondary must be
connected to phase A.
Single-phase
D – D
The secondary of this transformer is a two-wire ungrounded system
(single-phase Delta). Although you connect the load to only one
phase, it is in fact connected between the two wires. CYME reports
the current on one wire only since the other carries the same current.
• The primary of this transformer is connected between two phases
(AB, BC or CA).
• The primary of this transformer must be connected to a two-
phase section.
• Downstream sections and loads must be single-phase. See table
below.
Primary phases Secondary phase Load phase
AB A A
BC B B
CA C C
Example: If the primary side is connected between phases A and B,
any load or section connected to the secondary must be
connected to phase A.
set to Delta (D).

Example: The main feeder is a 3-phase section (phase ABC). The
lateral starts with a two-phase section (phase AB) and a
single-phase transformer D-D is set at the end of this
section. The downstream section from the transformer is
a single-phase section (phase A) and the delta load is
connected at the end of this section on phase A.
5.2.7 Three-phase Configurations
5.2.7.1 Common Configurations
The common configurations for three phase transformations are Wye-Wye (Y-Y),
Wye-Delta (Y-D), Delta-Wye (D-Y) and Delta-Delta (D-D). The transformation could be
realized by placing three single-phase transformers or one three-phase transformer.
The phase shift is in reference with the primary side and is clockwise.
Three-Phase
Ygrd – Y grd
• The primary of this transformer must be connected to a three-
phase section.
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (YNyn1)
Three-Phase
D – D
• The primary and the secondary of this transformer must be
connected to a three-phase section.
set to Delta (D) or Wye (Y). If load configuration is set to Wye
grounded (Ygrd), CYME sees the load as Delta (D).
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (Dd0)
Three-Phase
Ygrd – D
• Phase shift:
o Step-Down Transformer: 30° (Ygd1)
o Step-Up Transformer: -30° (Ygd11)
Three-Phase
D – Y
phase section.
• Phase shift:
o Step-Down Transformer: 30° (Dy1)
o Step-Up Transformer: -30° (Dy11)

Three-Phase
D – Ygrd
phase section.
• This configuration should be use only with balanced network.
• Phase shift:
o Step-Down Transformer: 30° (Dyg1)
o Step-Up Transformer: -30° (Dyg11)
5.2.7.2 Other Configurations
Other configurations supported in CYME:
Three-Phase
Ygrd – Y
phase section.
• This configuration is valid only when running a Balanced Voltage
Drop.
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (Ygy0)
Three-Phase
Ygrdo – Do
• CYME will not calculate the current for a short-circuit on the
secondary of an open-wye transformer.
• CYME will not use the third phase on the primary side and will
not report any current on it.
• Phase shift:
o Step-Down Transformer: °30° (Yodo1)
o Step-Up Transformer: °-30° (Yodo11)
Three-Phase
Do – Do
• The opened phases must be specified (AB, BC or CA).
• The downstream section on the secondary side must be three-
phase
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (Dodo0)
Three-Phase
Y – D
set to Delta (D) or Wye (Y). If load configuration is set to Wye
grounded (Ygrd), CYME sees the load as Delta (D).
• Phase shift:
o Step-Down Transformer: 30° (Yd1)
o Step-Up Transformer: -30° (Yd11)
Three-Phase
Y – Y and
phase section.
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (Yy0)

Three-Phase
Y – Ygrd
phase section.
• This configuration in valid only when running a Balanced Voltage
Drop.
• Phase shift:
o Step-Down and Step-Up Transformer: 0° (Yyg0)
ZigZag • One end of each phase winding is connected to a common point
(neutral point).
• Each phase winding consists of two parts in which phase-
displaced voltages are induced.
5.3 Two-winding Auto-transformer
5.3.1 Two-winding Auto-transformer Properties
An auto-transformer is a transformer where both the input and output circuit are sharing
the same winding. Therefore, there is no isolation between them. A two winding transformer can
be connected as an auto-transformer.
5.3.1.1 General Tab

Transformer
Type
Three types are available: Single-phase, Three-phase Shell and
Three-phase Core. The latter requires three sets of zero-sequence
values compared to one for the other two types.
Nominal
Rating
Total kVA for 3-phase Type auto-transformer or per phase for 1-
phase Type.
Primary
Voltage
Secondary
Voltage
kV line-to-line.
kV line-to-line. For any winding of a 1-phase auto-transformer
which is connected line-to-ground, enter (line-ground voltage) x √3.
No load
losses
kW Total for 3-phase and kW per Phase for 1-phase.
Reversible If Reversible is not active, then you will be prevented from closing
any switch that would direct power flow from the auto-transformer
secondary side to its primary side.
Sequence
Impedances
Positive-sequence Impedance Z1 in percent on auto-transformer
kVA base, zero-sequence Impedance Z0 in percent on auto-
transformer kVA base, positive sequence (X1/R1) and zero-
sequence (X0/R0) ratios.
If you click on the Default button, CYME will suggest typical values
for Z1, Z0 and X/R based on the kVA and primary voltage.
In a three-phase core transformer, zero-sequence impedance and
ratio are required for the following combinations: primary-
secondary, primary-magnetizing, secondary-magnetizing.
Grounding
Impedances
Grounding resistance and reactance for the grounding connection.
Configuration YG connection only.
Note: If you connect a 1-phase unit to a 2-phase or 3-phase section, identical
transformers will be installed in each phase.
5.3.1.2 Load Tap Changer (LTC) Tab
The data for the on-Load Tap Changer (LTC) should be set to zero unless the
auto-transformer is equipped with such a device.

Bandwidth Is the tolerance on the voltage that the LTC must maintain; in percent
of the base voltage. (see 5.3.2 Two-winding Auto-transformer Settings)
Taps Is the number of discrete tap positions in the LTC.
Maximum /
Minimum
Range
Is the range of voltage boost/buck covered by the taps.
5.3.2 Two-winding Auto-transformer Settings
Primary To indicate on which node the primary of the auto-transformer is
connected.
Fault
Indicator
To indicate via a signal that the fault is located downstream of the
device. The Reliability Assessment Module (RAM) uses this
parameter. See the Reliability Analysis Users Guide.
Fixed Tap
Group Zone
To enter primary and secondary taps setting of this particular auto-
transformer, either to raise or lower the voltage.
Grounding
Impedance
Grounding resistance and reactance for the grounding connection.
Configuration YG connection only.
System Base
Voltage
To define the primary and or secondary base voltage. Mark check
User defined to enable voltage field.

5.3.3 Auto-transformer Meter Settings
Location To indicate on which side (Primary or Secondary) of the two-
winding auto-transformer the meter is connected.
Diversity Calculates the diversity factors based on the demands of each of
the feeders and the transformer demand. The value calculated is
displayed in the Diversity field.

different consumer categories.
To display a summary of downstream load and capacitors, for
type.

5.4 Transformer – Three-winding
A three-winding transformer is capable of tap changing under load, to try to maintain a
desired voltage at a particular bus.
5.4.1 Three-winding Transformer Properties
5.4.1.1 General Tab
Nominal
Rating
Transformer total kVA.
Rated
Voltage
Enter the voltage in kV Line-Line for the primary, the secondary and
the tertiary sides.
Prim-Sec Measured from primary to secondary, in per-unit on primary base
power.
Prim-Ter Measured from primary to tertiary, in per-unit on primary base
power.
Sec-Ter Measured from secondary to tertiary, in per-unit on primary base
power.
Z1 Positive sequence impedance in %.
Z0 Zero-sequence impedance in %.
X0/R0, X1/R1 The ratio of the reactance to the resistance.
Phase Shift The angle by which one side leads the other.
Configuration There are three types of winding connection: GY, Y, D

Rg, Xg Grounding impedances (in ohms) for the grounding connection of the
primary/secondary and the tertiary, respectively. (Applies to GY
winding connection only.)
No load
Losses
The core losses plus winding losses at no-load, in kW.
5.4.1.2 Load Tap Changers Tabs
Load Tap
Changer
Mark check to enable the parameters below.
Lower / Upper
Bandwidth
Lower and upper tolerance on the voltage that the LTC is to
maintain in %.
Minimum/
Maximum range
Is the range of voltage boost/buck covered by the taps. To fix the
tap at a certain value, set Min = Max.
Number of taps The number of (equal) taps into which the voltage range is
divided. It is usually an odd number, to provide a center tap.

5.4.2 Three-winding Transformers Settings
Primary Tap Tap setting at the primary of the transformer.
Secondary Tap Tap setting at the secondary of the transformer.
Primary The primary base voltage in kV.
Secondary The secondary base voltage in kV.
Tertiary The tertiary base voltage in kV.
User defined Mark check to enable and modify the corresponding system
base voltage.

5.4.3 First / Second Load Tap Changer
If you entered data for a Load Tap Changer when you created the three-winding
transformer in the equipment database, then the Load Tap Changer sub-layers will appear
directly under the Three-Winding Transformer – At Middle layer.
Location To indicate on which side of the transformer the Load Tap Changer is
connected. For the First Load Tap Changer, it is Primary or
secondary.
For the Second Load Tap Changer, it is always tertiary.
Mode The different methods to obtain the settings for the transformer. See
Operating Mode in chapter 4.3 Regulator Control.
LDC
settings
R: Resistive voltage drop on the line between the transformer and
the load location.
X: Reactive voltage drop on the line between the transformer and
the load location.
secondary of the transformer.
Use last
load flow
LTC was active.
option.

Is slave When connected in parallel, checkmark this option to enter a Master Id
for the three-winding transformer.
2. Specifying the Master transformer section ID.
calculation. (e.g., Voltage Drop).
5.5 Three-winding Auto-transformer
5.5.1 Three-winding Auto-transformer Properties
5.5.1.1 General Tab
Nominal
Rating
Auto-transformer total kVA.
Rated
Voltage
Enter the voltage in kV Line-Line for the primary, the secondary and
the tertiary sides.
Z1 Positive sequence impedance in %.

Z0 Zero-sequence impedance in %.
X0/R0, X1/R1 The ratio of the reactance to the resistance.
Configuration Primary-Secondary connection in GY or Y, tertiary in D.
Rg, Xg Grounding impedances (in ohms) for the grounding connection of the
primary/secondary. (Applies to GY winding connection only.)
No load
Losses
The core losses plus winding losses at no-load, in kW.
5.5.1.2 Load Tap Changers Tabs
Load Tap
Changer
Checkmark to enable the parameters below.
Lower / Upper
Bandwidth
Lower and upper tolerance on the voltage that the LTC is to
maintain in %.
Minimum/
Maximum range
Is the range of voltage boost/buck covered by the taps. To fix the
tap at a certain value, set Min = Max.
Number of taps The number of (equal) taps into which the voltage range is
divided. It is usually an odd number, to provide a center tap.

5.5.2 Three-winding Auto-transformers Settings
Primary Tap Tap setting at the primary of the auto-transformer.
Secondary Tap Tap setting at the secondary of the auto-transformer.
Primary The primary base voltage in kV.
Secondary The secondary base voltage in kV.
Tertiary The tertiary base voltage in kV.
User defined Mark check to enable and modify the corresponding system
base voltage.

5.5.3 First / Second Load Tap Changer
If you entered data for a Load Tap Changer when you created the three-winding auto-
transformer in the equipment database, then the Load Tap Changer sub-layers will appear
directly under the Three-Winding Auto-Transformer – At Middle layer.
Location To indicate on which side of the auto-transformer the Load Tap
Changer is connected. For the First Load Tap Changer, it is Primary or
secondary.
For the Second Load Tap Changer, it is always tertiary.
Mode The different methods to obtain the settings for the auto-transformer.
See Operating Mode in chapter 4.3 Regulator Control.
LDC
settings
R: Resistive voltage drop on the line between the auto-transformer
and the load location.
X: Reactive voltage drop on the line between the auto-transformer
and the load location.
secondary of the auto-transformer.
Use last
load flow
LTC was active.
option.

Is slave When connected in parallel, checkmark this option to enter a Master
ID for the three-winding auto-transformer.
2. Specifying the Master transformer section ID.
calculation. (e.g., Voltage Drop).
5.6 Grounding Transformer
In many existing systems, particularly the older ones, the system neutral is not available.
You may want to use grounding transformers to create a neutral in order to ground these
systems. Basically all grounding transformers configurations aim at the same objective. They
must present high impedance to normal three-phase current and a low impedance path for the
zero-sequence currents under line-to-ground fault conditions.
5.6.1 Grounding Transformer Properties

Rated Capacity Transformer total kVA.
Rated Voltage kV line-to-line.
Configuration The configuration is either Wye-Grounded or ZigZag.
Z1 Positive-sequence Impedance in percent on transformer kVA base.
Z0 Zero-sequence Impedance in percent on transformer kVA base,
X1/R1 Positive sequence ratio.
X0/R0 Zero-sequence ratio.
5.6.2 Grounding Transformer Settings
Rg Grounding resistance.
Xg Grounding reactance.
Configuration The configuration is either Wye-Grounded or ZigZag.

CHAPTER 6 – GENERATORS 49
Chapter 6 Generators
6.1 Synchronous Generator
6.1.1 Synchronous Generator Properties
This chapter covers the General and the Equivalent Circuit tabs of the dialog box.
Information about the Harmonic tab can be found in the Harmonic Analysis Users Guide.
6.1.1.1 General Tab
Notes: 1. 3-phase synchronous generators only are allowed.
2. The reactive power output will be fixed by the power factor if the
generator is not individually set to control its voltage. If it is controlling
its voltage, then the Max and Min kVAR limits will apply, and the power
factor will vary.
3. The Steady State, Transient, and Subtransient impedances will be
used for the short-circuit and fault flow analysis according to the short-
circuit parameters setting.

50 CHAPTER 6 – GENERATORS
Rated Voltage The generator nameplate voltage, in kV.
Active
Generation
This is only a default value. The value that will be used is defined in
the Synchronous Generator Settings.
Power factor It could be positive or negative. A positive power factor will indicate
that the generator generates both active and reactive power. A
negative power factor will imply that the generator generates active
power and consumes reactive power.
Configuration There are three types of winding connection: GY, Y, D
Reactive Power
Max / Min
When the generator consumes reactive power these values can be
entered as positive in the dialog box, but during load flow
calculation, the generator will absorb reactive power instead of
generating it.
Z (R, X) Steady state impedance may be given in per-unit on the generator’s
kVA base or in Ohms.
Z’ (R’, X’) Transient impedance may be given in per-unit on the generator’s
Z’’ (R’’, X’’) Subtransient impedance may be given in per-unit on the generator’s
Z0 (R0, X0) Zero-sequence impedance may be given in per-unit on the
generator’s kVA base or in Ohms.
Zg (Rg, Xg) The grounding impedance is always given in Ohms.
Click on this button to open the Impedance Estimation dialog box
where you can estimate the subtransient reactance (X’’), transient
reactance (X’), zero-sequence reactance (X0) and ratio X/R.

6.1.1.2 Equivalent Circuit Tab
Model Five models are available:
• Classical Model (type 1)
• Salient Pole – Transient Effect Only (Type 2)
• Salient Pole – Transient and Sub-Transient Effect (Type 3)
• Round Rotor – Transient Effect Only (Type 4)
• Round Rotor – Transient and Sub-Transient Effect (Type 5).
The number of parameters required will vary with the model
selected.
: For a better understanding of the parameters required for the
selected model, you may display its circuit diagram by
clicking on this button.
Mechanical
Data
These parameters values are required for all models. Enter either
“H” or “J” value for the inertia and the other value will be calculated
automatically.
The damping constant (KD) offers a way of introducing damping
torque, which is proportional to speed. A value of 1 to 3 p.u. is
sometimes used. However, if KD ≠ 0, and the speed of the machine
fall below its initial speed, then the active electrical power of the
machine will appear to be higher than the input mechanical power
from the prime mover. A value of KD = 0 is recommended.
Synchronous
Reactances
Xd and Xq are the synchronous reactances in the direct and
quadrature axes.

Transient /
Subtransient
Data
X’d and X’q are the transient reactances in the direct and
quadrature axes.
T’do and T’qo are the transient direct-axis and quadrature-axis
open-circuit time constants.
X”d and X”q are the sub transient reactances in the direct and
quadrature axes.
T”do and T”qo are the sub transient direct-axis and quadrature-
axis open-circuit time constants.
Saturation Data EU and EL are two values of per-unit terminal voltage found on the
open-circuit saturation curve for the synchronous machine.
Typically, EU = 1.2 p.u. and EL = 1.0 p.u. See diagram below.
SGU and SGL are saturation coefficients defined in the figure
below.
Open-circuit Saturation curve

6.1.2 Synchronous Generator Settings
You may alter all of the settings for a generator, including its status (Connected /
Disconnected).
If the generator is Connected, it produces active power equal to the amount specified in
the Active Generation field.
Control Type Three possible values: Voltage Controlled, Fixed Generation,
Swing.
• With “Voltage Controlled”, the machine will adjust its reactive
power to maintain the Desired Voltage at its terminals (subject
to the reactive power limits MAX and MIN).
• If it is “Fixed Generation” then the reactive power generated
during a voltage drop calculation is a fixed amount determined
by the stated active power and power factor:
1
PF
1
kWkVAR
2
−=
⎟
⎟
⎟
⎠
⎞
⎜
⎜
⎜
⎝
⎛
• A “Fixed Generation” type generator does not control the
voltage at any node/bus.
• If it is “Swing”, the generator will operate as an infinite power
source.
Hint: Use the “Swing” option to simulate the loss of a substation.
Feeders will be supplied by generators only (no substation).
At Node Node/Bus whose voltage is controlled by the generator. It will apply
only when the control type selected is “Voltage Controlled”.

Desired Voltage A “Voltage Controlled” type generator will produce the active power
specified and vary its reactive power to maintain the Desired
Voltage at the node/bus selected in field “At Node”.
A “Swing” type generator will produce (or absorb) excess power not
accounted for by other generators. It always controls the Desired
Voltage at the node/bus where it is connected.
Initial Angle Enabled only for “Swing” generators, it defines the initial voltage
angle for all node/bus in an analysis but it is fixed for Swing
generators. Optional, its value may be set to 0.
displays, if available, the consumption profile of the customer which
Id is shown.
Model as a
power system
unit
This option refers to short-circuit analysis based on IEC 60909-0©
Standard. It means that the generator will be considered as a power
system unit as far as there is one step-up transformer connected to
its terminal bus and also the option “Apply impedance correction
factors to…” Power station units (PSU) located in the “IEC
Parameters” tab of the “IEC Short Circuit Analysis Dialog” is
checked.
If you have the Transient Stability module and the Harmonic module installed, you will
notice that the Synchronous Generator item in the Devices tree list can be expanded to reveal
the Stability and Harmonic models. These models are discussed respectively in the Transient
Stability Analysis Users Guide and Harmonic Analysis Users Guide.

6.2 Induction Generator
6.2.1 Induction Generator Properties
6.2.1.1 General Tab
Notes: 1. 1-phase, 2-phase and 3-phase induction generators are allowed.
2. With the induction generator, only subtransient impedance will be
involved and it will be used in short-circuit and fault flow analyses when
the generator impedance setting is subtransient.
Rated Voltage Rated Voltage is the generator nameplate voltage, in kV.
Active
Generation
the Induction Generator Settings.
ANSI Motor
Group
Select Automatic to let CYME estimate the group according to other
motor parameters or select one group from 2, 3, 4, or 5.

Compute from
the Equivalent
Circuit / User
Defined
If you select the “User Defined” option, you may either type directly
the R and the X values in their respective data field or use the
Estimate function to estimate the subtransient impedance.
If you select the alternative option, R and X values will be calculated
according to the values you set for the parameters found in the
Equivalent Circuit tab. If you don’t know the values then you can
use the Estimate function.
R’’, X’’ Subtransient impedance may be given in per-unit on the generator’s
kVA base or in Ohms. These values can be estimated with the
appropriate estimation function.
Click on this button to open the Impedance Estimation dialog box
where you can estimate the subtransient impedance (R’’, X’’).

Rotor Type Three types are available: Single circuit, Double circuit and Deep
bar. The equivalent circuit diagram is shown for each selected type.
Estimation
Method
Locked Rotor / Full Load Test

Locked Rotor / No Load Test
Nominal Conditions Known
Starting Conditions Known

Stator /
Magnetizing /
Rotor
Impedance
If these parameters values are known, you may type them directly in
the fields provided. Otherwise, use the estimation function. Select
the estimation method for which you have data, and click on the
Estimate button. These values may be given in per-unit on the
generator’s kVA base or in Ohms.
Cage Factor Cage factor CFr and Cage factor CFx allows taking into account
skin and proximity effects. See the appropriate equivalent circuit
diagram.
Inertia of all
rotating mass
Enter either H or J value and the other will be calculated
automatically.
Click on this button to open the dialog box where you can estimate
the impedances.
The dialog box displayed will vary depending on the estimation
method selected (See Estimation Method above).
6.2.2 Induction Generator Settings
Status The generator status (Connected, Disconnected)
Active
Generation
The active power produced by the generator.

Accesses the optional Energy Profile Manager module and displays
the generator profile.
If you have the Harmonic module installed, you will notice that the Induction Generator
item in the Devices tree list can be expanded to reveal the Harmonic model. This model is
discussed in the Harmonic Analysis Users Guide.
Note: Induction generator cannot have voltage control.
6.3 Electronically Coupled Generator
6.3.1 Electronically Coupled Generator Properties
Electronically coupled generators are units that are not directly connected to the system.
They are connected via inverter-based units such as HVDC links. For electronically coupled
generator, the inverter control mode is set such that, during short circuits, the source will continue to
contribute a percentage of its rated current.
Rated Voltage Rated Voltage is the generator nameplate voltage, in kV.
Active
Generation
the Electronically Coupled Generator Settings.

Fault
Contribution
Percentage of rated current the generator would contribute if a fault
occurred in the system. This is only a default value. The value that
will be used is defined in the Electronically Coupled Generator
Settings.
ANSI Motor
Group
Select Automatic to let CYME estimate the group according to other
motor parameters or select one item from 2, 3, 4, or 5.
Converter The inverter-based unit that connects the generator to the system
(HVDC, Others).
6.3.2 Electronically Coupled Generator Settings
Status The generator status (Connected, Disconnected)
Active
Generation
The active power produced by the generator.
Accesses the optional Energy Profile Manager module and displays
the generator profile.

CHAPTER 7 – MOTORS 63
Chapter 7 Motors
With CYME, you can simulate the effects of induction or synchronous motors starting in
distribution electric power systems (networks) and estimate the maximum motor size that can be
started on a given section.
7.1 Induction Motor
7.1.1 Induction Motor Properties
7.1.1.1 General Tab
Rated Power This value may be entered as kVA, Horsepower or kW. Enter one
value and the other two will be calculated, using the power factor
and efficiency.
Rated Voltage It is the motor nameplate voltage, in kV.
ANSI Group Select Automatic to let CYME estimate the group according to
other motor parameters or select one item from 2, 3, 4, or 5.

64 CHAPTER 7 – MOTORS
Compute from
the Locked
Rotor Data /
Compute from
the Equivalent
Circuit / User
Defined
If you select the “User Defined” option, you may either type directly
the R and X values in their respective data field or use the Estimate
function to estimate the subtransient impedance.
If you select the “Compute from the Equivalent Circuit” option, R
and X values will be calculated according to the values you set for
the parameters found in the Equivalent Circuit tab. If you don’t
know the values then you can use the Estimate function.
If you select “Compute from the Locked Rotor Data” option, R and
X values will be calculated according to the values you set for the
parameters in group zone Locked Rotor Data.
: Click on this button to select appropriate NEMA code.
: Click on this button to load default power factor value.
R’’, X’’ They represent the subtransient impedance and they are given in
per-unit on the motor’s own base power. They can be expressed in
Ohms if you select this option.
This button is enabled only when you select the “User Defined”
option. Click on it to estimate the subtransient impedance (R’’, X’’)
from the NEMA code letter and other (American) nameplate data.
(The NEMA letter identifies the ratio of inrush starting current to
rated full-load current.)

Locked Rotor
Data
group box
The Locked Rotor data determines the
model for the motor when it is starting.
The Starting power factor may
be estimated by clicking on this
button to load default power
factor value if necessary.
Click on this button to select
appropriate NEMA code from
the List of NEMA Codes dialog
box.
The NEMA code (from the motor nameplate) represents a range of
values of the starting kVA/HP ratio. It is for information, since only
the value entered for kVA/HP ratio will be used. A second option
is to define the locked rotor current (typically about 6 times the full-
load current).
Rotor Type Three types are available: Single circuit, Double circuit and Deep
bar. The equivalent circuit diagram is shown for each selected type.

Estimation
Method
Locked Rotor / Full Load Test
Locked Rotor / No Load Test
Nominal Conditions Known

Starting Conditions Known
Stator /
Magnetizing /
Rotor
Impedance
If these parameters values are known, you may type them directly in
the fields provided. Otherwise, use the estimation function. Select
the estimation method for which you have data, and click on the
Estimate button. These values may be given in per-unit on the
motor’s kVA base or in Ohms.
Cage Factor Cage factor CFr and Cage factor CFx taking into account skin and
proximity effects. See the appropriate equivalent circuit diagram.
Inertia of all
rotating mass
Enter either H or J value and the other will be calculated
automatically.
Click on this button to open the dialog box where you can estimate
the impedances.
The dialog box displayed will vary depending on the estimation
method selected (See Estimation Method).

7.1.2 Induction Motor Settings
Status Choose the motor Status (OFF, RUNNING, or LOCKED ROTOR), and
the number of starts per day.
Starts When RUNNING is selected, the normal motor load will be present at
the motor location. When motors are declared as running, the
contribution of these motors to the short circuit currents is neglected
because it decays quickly to zero.
Enable Load
Factor
Mark check this option so you can enter the desired load factor,
otherwise CYME will assume 100% of full load.
Loading Percentage of full load.
Power
Factor
The load power factor of the motor when it is operating at less than full
load.
7.1.3 Induction Motor Starting Assistance (LRA)

Six types of starting assistance are available. Depending on your choice, you may have
to define other parameters required by the model.
No Assistance
(Across the
Line)
Means the motor starts direct across the line (full circuit voltage is
applied to its terminals). This is the usual method.
Resistor and/or
Inductor
assistance
Places a resistor in series with the motor, to decrease the voltage
available at the motor terminals, so that the motor impedance will
draw less current. (In reality, the resistor is short-circuited after some
time delay, but this is not simulated.)
Resistance (R) and reactance (X) values are required for this type.
Capacitor
Assistance
Places a capacitor in parallel with the motor, to supply some of the
VARs drawn by the motor, and hence reduce the voltage drop.
The capacitor rating is required for this type.
Auto-
Transformer
Assistance
An auto-transformer steps the voltage down. (The auto-transformer
is not explicitly modeled, only its voltage ratio.) This method is used
to reduce the motor’s starting current, and is used to start very large
motors on weak systems. (In reality, the auto-transformer tap is
changed to 100% after some time delay, but this is not simulated.)
The Tap Position parameter is required.
If you want to take the transformer impedance into account by
checking the option Consider Auto Transformer impedance, you
will have to define:
• The Nominal Rating in kVA
• The Primary Voltage in kVLL
• The Nominal Z in %
• The X/R Ratio .
Star-Delta
Assistance
To switch from a Delta to a Wye connection in order to reduce the
starting current.
Variable
Frequency
Starter
To specify the starting current as a percentage of the nominal current
or as a percentage of the motor locked rotor current. The basic idea
is that the induction motor is fed by a variable frequency source
controlled by a Pulse-Width-Modulation (PWM) inverter.
IM
Rectifier PWM Inverter
Istart
System Bus
Motor fed by PWM inverter with constant V/F control

If you have the Harmonic Analysis, the Transient Stability Analysis or the Dynamic Motor
Starting modules installed, you will notice that the Induction Motor item in the Devices tree list
expansion reveals the Starting Assistance (MSA), the Load Characteristics, the Dynamic Model,
and the Harmonic model. These models are discussed in the Transient Analysis Users Guide
and the Harmonic Analysis Users Guide. See also the Dynamic Motor Starting Users Guide for
additional information about the motors models.
7.2 Synchronous Motor
7.2.1 Synchronous Motor Properties
This chapter covers the General tab and the Equivalent Circuit tab of the dialog box.
Information about the Harmonic tab can be found in the Harmonic Analysis Users Guide.
7.2.1.1 General Tab
Rated Power This value may be entered as kVA, Horsepower or kW. Enter one
value and the other two will be calculated, using the power factor and
efficiency.
Rated Voltage Rated Voltage is the motor nameplate voltage, in kV.
Z’’, Z0, Z The subtransient impedance (Z’’), zero-sequence impedance (Z0)
and internal impedance (saturated value Xd) can be expressed in
Ohms or in per-unit on the motor’s base power
Zg The grounding impedance is always given in Ohms.

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