1. TECHNICAL AUDIT REPORT
OF
MANERI BHALI HYDRO POWER PLANT
STAGE-I, 3X30 MW (MB-I)
&
STAGE-II, 4X76 MW (MB-II)
of
UTTRAKHAND JAL VIDUYAT NIGAM
LIMITED
BY:- Er. J S Pabla

2. TECHNICAL AUDIT REPORT
OF
MANERI BHALI POWER PLANTS
1. CIVIL WORKS
2. HYDRO MECHANICAL EQUIPMENTS
3. ELETRO MECHANICAL EQUIPMENTS

3. MEMBERS OF TECHNICAL AUDIT TEAM
1. Er.V.K.Kanjlia, Secretary/CBIP, & Former E.D./ NHPC
2. Er.V.K.Kapoor, Former E.D./ NHPC
3. Er.A.K.Sachdeva, Former E.D./ NHPC
4. Er.P.P.Wahi, Director/CBIP & Former C.E/BBMB
5. Er.A.C.Gupta, Director/CBIP & Former Executive
Member/Naravda Control Authority (NCA)
6. Er.J.S.Pabla, Advisor (Power) & Former C.E/BBMB
7. Er.Hakam Singh, Asstt. Manager (Technical)

4. REPORT ON MANERI BHALI POWER
PLANT STAGE-I (MB-I) - 3X30 MW
A. Generator
 Excitation system: Automatic Voltage Regulator
(AVR) of all the units is on manual control. Auto
circuit needs to be resort.
 Insulation Resistance (IR) recorded as 44.5 MΩ (15
Sec), 105.8 MΩ (60 Sec) & 366 MΩ (600 Sec) in
respect of unit-II is low. Heat run of generator may
be carried out and values recorded again.
 At present status of brake pads is checked
physically before start of unit as most of the limit
switches provided for brakes “ON” & “OFF” lamp
indications are defective in respect of all the units.
Limit switches need replacement on priority.

5.  Defective water flow relays for Upper Guide Bearing
(UGB), Lower Guide Bearing (LGB) & Thrust
Bearing (TB) of all generators need to be replaced.
 Defective cooling water Pressure gauges of LGB of
unit-II & III need to be replaced.
 Oil level High/Low indicating relays for UGB, LGB
& TB of all generators are defective & need repair /
replacement.
 Auto circuit of braking unit for all machines is out of
order & brakes are applied manually at 25% rated
speed. Auto circuit needs to be restored.
 Most of the RTDs provided for Stator Core, Stator
Winding, Cold Air etc. are defective.

6. TSD’s for Thrust Bearing (TB) showing
temperatures as 61ºC & 69ºC for Unit No.1
need to be calibrated/replaced.
TSD’s for UGB (Pad No.4), LGB (Pad No.3 &
7) & TB (Pad No.1 & 5) for Unit No.2 are
showing either high or low readings. Needs to
be calibrated/replaced.
Defective TSD’s for LGB pad number 3 & 5
showing temperatures as 12ºC and 40ºC for
Unit No.3 need to be calibrated/replaced.
Defective TSD for TB pad number 5 showing
temperature as 36ºC for Unit No.3 needs to be
calibrated/replaced.

7. B. Turbine
 Heavy leakage of water observed from turbine gland
shaft seal & top cover of Unit No.2 & 3, needs be
rectified during annual maintenance.
 Marking scale on servo motor (all units) showing the
position of guide vanes is missing.
 Centralised Grease Lubricating (CGL) system
automation for all units is out of order.
 CGL tank of Unit No.3 found empty. Needs to be
replenished with grease.
 Auto system of ejector unit is out of order.
 Alarm scheme for TGB oil sump, water flow relays &
CGL system needs to be made operative for all units.
 Defective cooling water Pressure gauge of TGB of
unit-II needs to be replaced.

8.  Oil level indicating relay for oil sump of Turbine
Guide Bearing (TGB) of Unit No.1 is defective.
Needs to be replaced.
 Defective TSD for TGB Pad No.5 showing temperature
as 30°C for Unit No.3 needs to be calibrated / replaced.
 Defective TSD’s for TGB Pad No.1 & 5 showing
temperatures as 42ºC and 35ºC respectively for Unit
No.2 need to be calibrated/replaced.

9. C. Governing System
 Governing System: All the units are running on
manual mode. Auto mode needs to be restored on
priority.
 In all units, leakage of oil from valves, lever pins etc.
on top cover of oil sumps of Oil Pressure Units
(OPU)
has been observed. Needs to be attended.
 In all units, auto circuit of governor oil pumps for Oil
Pressure Unit (OPU) is faulty. Needs rectification.
D. Power Plant Control Room
 At present all the units are synchronised with the grid
manually. Auto synchronisation though
commissioned needs to be made operative.

10.  All the protective relays for units, transmission lines,
Bus-Bar etc. have been tested by Alsthom during
8/2014 but report still awaited. Needs to be expedited.
 Faulty “Pole Trip Circuit-2 Supervision Relay C” for
220kV Bus-Coupler needs to be replaced.
 Control & protection schematic drawings are required
to be displayed in the control room for the guidance
& knowledge of operational staff.
 Air conditioning system not provided in the control
room. As static numerical relays are installed on
220kV transmission lines and Bus-Bar panels, A.C.
system needs to be provided.

11. E. Unit Transformers (T-1 to T-3)
 Break Down Voltage (BDV) recorded as 40kV &
48kV in the first two shots for transformer T-3 is lower
than the recommended value of 50kV (minimum)
indicating that the transformer oil is not healthy &
needs to be filtered on priority. Due to same reason
Polarisation Index (PI) value (1.14) is also low which
may be due to higher content of water (PPM) in
transformer oil.
 Minor oil leakage observed from valves, flanges,
Buchhloz relays etc. for all the unit transformers needs
to be rectified.

12.  Oil cooler pumps for all the unit transformers are run
manually as per requirement and not on auto with
rise in temperature of winding. Auto running of
these pumps with the rise in temperature of
H.V.winding needs to be made operational.
 Insulation Resistance (IR) in respect of transformer
T-2 recorded as 362 MΩ for both 15 Sec and 60 Sec
is same showing discrepancy in measurement. Needs
to be checked again during shut down to ascertain
the correctness of IR.

13.  In case of transformer oil, only Break down Voltage
(BDV) is recorded. To check the overall quality of
transformer oil other tests such as Water content
(PPM), Resistivity, Acidity, Flash Point, Interfacial
Tension, tan delta, Pour Point, Dissolved Gas Analysis
(DGA) etc may be carried out annually during
summer.
 Colour of silicagel in the breathers of transformers T-1
& T-2 found to be pink & needs to be reconditioned /
replaced.
 Defective cooling water pressure gauge of transformer
T-1 needs to be replaced.
 To rectify leakage of water observed from the oil
coolers of transformer T-1.

14.  TSD’s provided for H.V. winding & oil temperature
of unit transformers T-2 & T-3 need calibration as
H.V.winding temperature is lower than the oil
temperature.
 To protect unit transformers against any fire
incidence, Nitrogen Injection Fire Protection System
(NIFPS) is recommended.
 Lighting lamps & heaters of Marshalling Kiosks
(MK) in respect of all unit transformers need to be
made operational.
F. D.C.Batteries
 Temperature correction chart for specific gravity
needs to be provided in the D.C.Battery rooms of
Power Plant & Switchyard.

15. G. Unit / Station Auxiliaries
a) Fire Fighting
 In order to prevent major fire hazard to the
equipments installed in the Power House Control
room and power & control cables in the cable gallery,
fire protective system is recommended to be provided.
 Date of refilling of DCP /CO2 cylinders needs to be
marked on each cylinder. Records of refilling of
cylinders also be maintained for ready reference.
 Portable DCP/CO2 cylinders placed at various
locations for fire fighting are inadequate. More
cylinders need to be placed at vulnerable places.

16. b) H.P. Compressors
 Auto operation of H.P. compressor motors is faulty.
c) Dewatering & Drainage pumps
 Level switches of Dewatering & Drainage pumps are
defective and hence, auto circuit of these pumps is
faulty.
d) Over Head Crane
 Alignment of rail track for over head crane needs to be
checked & rectified.
 For smooth running of cranes in parallel, complete
overhauling needs to be carried out.
 Sparking & over heating of power cables observed when
cranes are in operation. Defective & undersized power
cables need to be replaced with XLPE / FRLS cables.

17. e) 11kV / L.T. supply Panels
 Regular testing of oil & maintenance of 11kV MOCB’s
may be carried out pending replacement under R&M.
 Fused lamps or defective assemblies of lamp indications
on 11kV MOCB’s need to be made operational.
 Various lamp indications on L.T. panels / boards are out
of order & need to be made operational.
 11kV MOCB’s room found very dusty. Needs regular
cleaning.

18. H. Switchyard
a) 220 kV System
 Main isolators for Unit No.1 & 2 connecting to 220 kV
Bus-A are not closing properly and are at about 80
degree. Immediate alignment of these isolators is
needed.
 Broken R-ph Surge counter of LA in respect of 220kV
feeder No.82 needs to be replaced.
b) Power Transformers 25MVA 220/33KV (T-1 & T-2)
 Silicagel breather for Transformer T-1 is near the oil
level gauge of conservative tank which is approachable
only after switching off the unit transformer & providing
temporary earthing. Needs to be extended at
approachable height from the ground.

19.  Colour of Silicagel in breathers of transformer T-1 &
OLTC of transformer T-2 found to be pink and needs to
be reconditioned / replaced.
 Two number cooling fans of radiator of transformer T-1
found to be removed & need to be restored for proper
cooling of transformer oil.
 TSD’s for oil & H.V. winding of both the transformers
need calibration.
c) Air Driers
 Air driers provided for dryness of air for pneumatic
control of isolators are full of dust & web-cobs & needs
regular cleaning.
 All the lamp indications on air drier panels of both the
air driers units not working. Needs to be made
operational.

20. d) 33 kV System
 Regular testing of oil & maintenance of 33 kV
MOCB’s may be carried out pending replacement
under R&M.
 At many places strands of 33 kV Main Bus conductor
found broken, repaired and even loose. 33 kV Main
Bus conductor for such sections needs to be replaced
on priority.
 Conductor strands of number of 33 kV jumpers in 33
kV yard areas found broken / repaired. These need to
be replaced on priority.

21. e) Yard Area
 Lighting provided in the yard areas is inadequate.
More lighting fixtures need to be provided.
 Growth of wild grass observed in the yard area
which needs to be removed.
I. General
 Illumination in most of the control & protection
panels, excitation panels, Governor panels,
Marshalling kiosk etc. at various floors/switchyard
not functional. Maintenance staff carries out day
to day maintenance activities with the help of hand
lamps. Fused lamps / tubes in panels need to be
replaced.
 Number of Machine Hall tiles are badly broken/
damaged & require replacement.

22. J. Records/Manual
 Maintenance schedule for each equipment needs to be
prepared. Maintenance needs to be carried out
according to these schedules & recorded/documented
in proper formats.
 History Sheet of each equipment installed in the Power
Plant i.e. Name of equipment manufacturers,
Make, Type, Date of installation/commissioning,
Detail of major failures, repair & replacement
carried out etc. need be maintained.
 Unit wise/equipment wise Fault record history i.e.
Detail of all faults occurred since its commissioning
along with time/date of occurrence, nature of fault,
Protection operated, analysis of fault, action taken to
restore the equipment, remedial measures taken etc.
need be maintained.

23.  Maintenance Record of testing of various
equipment such as protective relays, power
transformers, transformer oil, generator, excitation
protection system, Breakers, Current Transformer,
Capacitive Voltage Transformer (CVT), Isolators
D.C. batteries, Unit/Station Auxiliaries need be
maintained / documented for ready reference.
 Record of Maximum temperature recorded for
important parameters such as Power Transformer
oil & winding temp., UGB/LGB/TB/TGB/Stator
winding/stator core/ Hot/ cold air temperatures etc.
is available in log sheets. Same needs to be
maintained in a register for ready reference.

24.  Operation & Maintenance Manual is required to be
prepared for the guidance of O & M staff, safe
operation & preventive maintenance of plant
equipment on priority. Important information included
in the Operation & Maintenance manual may be as
under:
 General Layout
 Details of civil structures
 Hydro Mechanical & Electro Mechanical data of
various equipment installed
 Starting/stopping sequence of unit
 Control & Protection Relay Panels
 Auxiliary Supply System
 D.C. System
 Governor, Excitation & synchronising scheme

25.  220 kV Sub-Station control
 Protection, Signals & Annunciations
 Maintenance Schedules for each equipment
 Miscellaneous Operating Instructions
 Trouble shootings, Possible Causes & their Remedies
 Fire Protection System
 List of Drawings & equipment manual
 Civil Defence Measures etc.

26. THANKS