Automatic Cyclic Load Shedding in Distribution System

Guided by:Prof. A.K Tripathy

Presented By:Biswarup Mandal-1201209195Satyajit Singh -1201209214Mukesh Ranjan -1201209180Tulika Singh -1201209186Saurav Sahoo -1201209193

EEE (A)Group-1

Contents:1) Objective of the project

2) Why Load Shedding?

3) Intelligent Load shedding approach

4) Load Curve

5) Proposed Block Diagram 6) Conclusion

7) Future Work

8) References

Objective Of The Project

Study of power generation and load demand of a locality. Strategy to Handle the shortage in meeting Load demand

through an Intelligent Load Shedding System .

The need for load shedding generally arises from unforeseen causes, lack of sufficient power supply from deficiencies in generating, transmission and distribution capabilities.

There are certain other causes as enlisted below which often restrict us from anticipating correct amount of load i.e.

Unusual Seasonal changes Special events that may cause loss of diversity, and Rapid growth of industrialization .

The Need For Load Shedding In Distribution System

Analogy Of Load Shedding With Real World

Intelligent Load Shedding Approach

Doesn’t allow the frequency to decrease.Continuous monitoring of all power sources.Dynamically calculate the amount of load shedded at any time. Selectively remove load on priority basis.

To achieve faster load shedding system keeps history of past events of a particular area(i.e feeder under a substation).The curve showing the variation of load on the power station w.r.t time is known as load curve.

IMPORTANCE-Area under LC=Units generatedMaximum demand Helps in selecting no and size of generating unitsHelps for future plan

Load Curve

Block Diagram of Project

Distribution System

Power Supply Section

Relay Section

MicroController Section

Load Section

Overall Block DiagramDISTRIBUTION

TRANS-FORMER

DISTRIBUTING POLE

AC SUPPLY 1 PHASE SUPPLY

CURRENT

TRANS-FORMER

CIRCUIT BREAKER

& RELAY CIRCUIT

LIGHT LOAD

HEAVY LOAD 1

12V AND 5V

DC SUPPLY MICRO

CON-TROLLER

ATMEGA16LCD DISPLAY

BUZZER

FEEDBACK

SWITCH

HEAVY LOAD 2

Hardware Components :The proposed project requires the following hardware:

1. Stabiliser transformer (250 VA,230V)2. Current transformer3. Relay (12 V,6 amp)4. Microcontroller (ATMEGA-16)5. Transistor (n-p-n) (BC547)6. Capacitor (4.7uF,470uF)7. Diode8. Resistor (1K,10K)9. Ply board (3 ft * 2 ft)10. Bulb (100 Watt (2 no.s), 200 Watt)11. Vero board (5 no.s)

Distribution Section

230V 1-Phase

AC Supply

1:1Shell Type Transformer

1-Phase Transmission

lineCT

LOAD

Heavy Load

Light Load

Power Supply Section

230V 1-Phase

AC Supply

1-Phase Rectifier

Step Down Transformer

Voltage Regulator

Relay Section A relay is usually an electromechanical device that is actuated by an electrical

current.

The current flowing in one circuit causes the opening or closing of another circuit.

Relays are like remote control switches and are used in many applications be-cause of their relative simplicity, example circuit using a relay to power a 120v load long life, and proven high reliability.

MicroController Section ATmega16 has 16 KB programmable

flash memory, static RAM of 1 KB and EPROM of 512 Bytes.

The endurance cycle of flash memory and EPROM is 10,000 and 1,00,000, respectively.

ATmega16 is a 40 pin microcontroller. There are 32 I/O(input/output) lines which are divided into four 8-bit ports designated as PORTA, PORTB, PORTC and PORTD.

Load Section

There are 2 types of load connection- heavy and light. The light load(100 W) is directly connected via switch. The heavy loads (200W and 100W) are connected through circuit

breaker. When the load value increases a certain max value, say 300W, the

buzzer starts ringing If within 10sec if the extra load is not removed, then the heavy load

part will be tripped off.

Future Work

Existing load shedding process is done manually.

As we all know that any low cost mobile phone is capable of sending text messages, hence this SMS based shedding scheme will be very cheap and easy to operate.

Here we’ll use commands(AT) carried out by GSM modem, which would reduce the human involvement to a great extent

The proposed system would work on a certain set of algorithm, which will be explained in our major project

Conclusion

Load shedding in industrial power systems serves as the ultimate guard that protects the system from an overload induced collapse.

In this project, the importance of a timely applied load-shedding action has been reconfirmed. If the specific action is not performed in time, a more painful load-shedding action must be performed in order to avoid a voltage collapse.

Finally we can say that, by using microcontroller the control of load shedding can be made more easily.

References

L. A. Finley, T. R. Standish, R. C. Phillips, "Optimizing system performance through dynamic load shed scheduling" IEEE Transaction on Power Apparatus and systems, Vol. PAS-I04, pp. 1286-1289, Jun.1985.

Load Shedding – An Application Guide, John Berdy, General Electric Company Electric Utility Engineering Operation, Schenectady, N.Y.

www.wikipedia.org www.google.com Electrical Power System by C L Wadhwa New Age International Publishers.

(4th Ed),(Book3)