Load shed

1. A Presentation On Load Scheduling &
Load Shedding
Presenting By:
Gehlot Darshan
B.Tech 4th Year
Guided By:
Prof. R.R. Joshi
Head of Department
Department of Electrical Engineering
College of Technology and Engineering, Udaipur

2. Contents
 Introduction
 What is load
 Load Scheduling in Power Systems
 Need for load Schedule
 Load Shedding
 Effect of excess load
 Reason For Instability
 Advantages & Disadvantages
 Conclusion

3. Introduction
• Now a days electricity loads are
increasing day by day. So it is
important to manage the supply
side for optimal operation.

4. Load
• An electrical load is an electrical
component or portion of a circuit
that consumes (active) electric
power. This is opposed to a power
source, such as a battery or
generator, which produces power

5. Load Scheduling in
Power Systems
• The electrical load scheduling is the
process of estimating the instantaneous
loads operating in an installation.
• The load schedule provides the load for
the particular installation in terms of
apparent, reactive and active power (kVA,
kVAR and kW) and usually carried out at
the sub facility area or at the switchboard.

6. Cont.
 The load schedule preparation should ideally be the first task to perform
during the electrical system design stage since it relates to the equipment
sizes and other power system requirements.
 Load scheduling is one form of load management action that allows
companies to save energy by minimizing their demand.
 In order to have an efficient load schedule operation, the energy manager or
business should conduct power logging and record all sessions so as to
measure the usage of energy over a specific time.

7. Need for load Schedule
 Preparing an electrical load schedule eases the work of
designing the system in terms of equipment sizing as well as
in power system studies. The process requires an
understanding of the installation, all the equipment that will
be installed, frequency of using the equipment and their
importance or criticality.
 The load schedule should ideally be started as early as is
practically possible in the design process. One requires an
idea of the main voltage levels required in the installation as
well as all other details of the function of the facility or
building, and the nature of process and non process loads.

8. Load Shedding
• Load shedding in electrical supply
networks is a controlled process in
which the utility company drops off
part of the load in order to balance the
demand and the generated capacity.
• This is often done whenever there is
excess load on , it involves
disconnecting or shedding some
circuits to prevent an overload
condition.

9. Effect of excess load
 Stress on the generating equipment.
 It slows down the prime movers, associated generators and other parts of the system as they attempt to cope
with the excess load.
 Protection systems may interrupt the supply due to the excess current resulting from the overload.
 The higher load may also lead to a lower generating and supply frequency.
 The reduced frequency can damage the steam turbines as well as the frequency sensitive load.

10. Reason For Instability
 Inefficiency and lack of maintenance of generating and distribution systems
 Increased population
 Improved living standards
 Lack of planning

11. Load Shedding Procedures
 Utility companies use scheduled load shedding so that the available electricity is fairly
shared by the consumers. This involves switching off some parts of the electricity supply
network in a planned and controlled process. They alternate between different parts and
time schedules to ensure that at least everyone gets power at a specific time. By dropping
off the excess load, the power system remains stable.
 Some smaller generators such as those used in domestic applications have inbuilt load
shedding capabilities. This becomes necessary when these are used as standby
generators, in the event of a utility power outage, the emergency supply kicks in. And since
all the circuits and appliances are connected, the load demand may exceed the generator
capacity. When the load becomes too much, the generator sheds some of the smaller non-
critical circuits automatically in an attempt to reduce the load.

12. Advantages
 Prevents overloading and damage of the power generators
 Prevents instability and system collapse of the electrical generation
and distribution systems
 Ensures that consumers or parts of the network have poweras
opposed to a total blackout.
 The planned schedules ensure that available capacity is shared fairly
and each consumer gets power at one time or another.
 It serves as a warning to the utility hence forcing them to increase
capacity, and efficiency so as to meet the demand.

13. Disadvantages
• LOSS OF PRODUCTION
• INCREASED CRIME DUE TO
DARKNESS AND
LACK OF JOBS
• THE UTILITIES MAY NOT
INCREASED THE OUTPUT
• RESTORING THE LOAD MAY CAUSE
MORE INSTABILITIES

14. Conclusion
 Electrical load scheduling is an essential practice that an electrical technician should
carry out at the initial stages of an electrical power installation. The load schedule
provides data that isa close estimate of the amount of power consumed for normal
and peak loads and anything in between
 Load shedding is one of the last things that a utility company should look at. It leads
to frustrated customers and loss of revenue for the consumers as production drops.
In addition,it may cause equipment damage.
 Electricity companies should ensure that they have enough capacity to meet normal
andpeak demands. This can be achieved by planning for future electricity demand
and progressively upgrading the generating equipment, maintain existing systems,
reducing transmission losses and increasing efficiency in the entire system.