OVER VIEW OF220KV/132KV/33KV KONDAPALLI STATION

PRESENTED BY:

R.DIVYA BHARATHI 08AJ1A0244J.ASHOK 08AJ1A0216V.KOTESHWARA RAO 08AJ1A0222R.JAGADEESH BABU 08AJ1A0242

Under the esteemed guidence of:

INTERNAL GUIDEK.RAJESH BABU(Asst.Prof.)

EXTERNAL GUIDEB.SRINIVASA RAO (Asst.Div.Engg)

INTRODUCTION

The Andhra Pradesh state transmission corporation (APTRANSCO) with its 12502.58 circuit KM of 220KV lines ,14938.57 circuit KM of 132KV lines -Serving 5.101 lakhs of industrial consumers -22.4 lakhs of agricultural -112.02 lakhs of domestic consumers.

In the recent past AP TRANSCO has entered in to the era of 400KV system by commissioning seven numbers 400KV/220KV substations.

The Kondapalli 220KV substation is an outdoor type substation with 220KV, 132KV and 33 KV features

CLASSIFICATION OF SUBSTATIONS

Subsystem

Service requirements -Transformer sub-stations -Switching sub-station -Power factor correction sub-stations -Frequency changer sub-stations -Converting sub-stations -Industrial sub-stations

Constructional features

- Indoor sub-station -Outdoor sub-station -Underground sub-stations -Pole mounted sub-stations

S.NO PARTICULAR OUTDOOR SUB-STATIONS

INDOOR SUB-SATATIONS

1 Space required More Less2

Time required for errection

Less

More

3 Future Extension Easy Difficult

4 Fault location Easier because the equipment is in full view

Difficult because the equipment is enclosed

5 Capital cost Low High

6 Operation Difficult Easier

7 Possibility of fault escalation

Less because greater clearances can be provided

More

 Comparision between Outdoor and Indoor sub-stations

TYPICAL OUTDOOR SUB-STATION

BUSBAR ARRANGEMENTS

The basic Arrangements of busbar are of following types

1. Main and transform bus. 2. Single bus bar. 3. Duplicate bus bar. 4. Ring and mesh bus bar. 5. One and Half circuit breaker system.

SINGLE BUS BAR RING&MESH BUSBAR

SINGLE LINE DIAGRAM OF KONDAPALLI SUB-STATION

PRINCIPLE AND WORKING OF SWITCHGEAR&PROTECTION EQUIPMENT

Current transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as instrument transformers

They are two types : a. Current transformer (CT) b. Voltage transformer (VT) REQUIREMENTS OF C.T . RATING FACTOR .ACCURACY .BURDEN

CURRENT TRANSFORMER

POTENTIAL TRANSFORMERS

CIRCUIT BREAKERS• A circuit breaker has two contacts:

-Fixed contacts-Moving contacts

Depending upon arc quenching medium circuit breakers are classified in to two types:(1)Oil circuit breakers(2)Oil less circuit breakersAgain Oil circuit breakers are classified into two types;(a)Bulk oil circuit breakers(b)Minimum oil circuit breakersOil less circuit breakers are classified into two types;(a)Air blast circuit breakers(b)SF6 circuit breaker(c)Vaccum circuit breaker

SF6 CIRCUIT BREAKER

AIR BLAST CIRCUIT BREAKER

• In air blast circuit breakers,compressed air at a pressure of 20-30kg/cm2 as an arc quenching medium

• They have also been used in 11kv-33kv range for certain applications.

• An air blast circuit breakers may be either of the following types:

1.Cross-blast circuit breakers. 2.Axial-blast circuit breakers.

AIR BLAST CIRCUIT BREAKER

LIGHTENING ARRESTERS

PROTECTIVE RELAYS

• Relay is piece of apparatus used for protection in high voltage circuits in place of fuse

• The short circuit may occur due to failure of insulation caused by

(a) Over voltage due to switching. (b) Over-voltage due to the direct and indirect lighting strikes. (c) Bridging of conductors by birds. (d) Break down of insulation due to decrease of its dielectric strength (e) Mechanical damage to the equipment’s

ISOLATORS• The main purpose of isolators is to isolate

one portion of the circuit from the other

INSULATORS• The insulator provide mechanical

support to the conductors and are subject to normal operating voltage and transient over voltage.

TYPES OF INSULATORS

a. pin type

b. suspension type

c. stray type

d. shackle type

e. stay insulator

TRANSFORMERS

WORKING PRINCIPLE OPERATION OF TRANSFORMER

BUCHHOLZ RELAY

• It is a gas actuated relay used for the protection of oil immersed transformer against all incipient faults

POWER LINE CARRIER COMMUNICATION

The communication and that date transmission from one substation to another substation is carried out by means of power line carrier communication PLCC system.

The PLCC equipment comprises of the following:1) Line trap unit2) Coupling capacitor3) Tuning unit4) Transmitter, receiver and other electronic

equipment

WAVE TRAP:

Wave trap is an inductive device, which offers high impedance to high frequency signals

CAPACITOR VOLTAGE TRANSFORMER

- Used in power systems to step down Extra high voltage signals and provide a low voltage signal, for measurement orto operate a protective relay

EARTHING SYSTEM

• In designing the substation,three voltages have to be considered:

1.Touch Voltage2.Step voltage3.Mesh Voltage

BATTERIES

• Batteries are the most vital equipment of the substation

CONCLUSION• The study of 220kv/132kv/33kv kondapali substation enabled to know typical

substation arrangements different makes of equipment like power transformers lighting arresters protective equipment circuit breakers, instrument transformer

• The conductors used for the 220KV Feeders are Zebra they can carry 735 Amp at 400 C And Moose they can carry 835 Amp at 450 C.

• The conductors used for 132Kv Feeders are Panther they can carry 482 Amp at 45◦ C

•The study provided good exposure to basic principles of substation working and was very much inspiring. It is noted that for a qualitative power transmission good maintenance of substation is essential.

BIBLIOGRAPHY

• Theory And performance Of Electrical Machines

• J.B.GUPTA

Electrical Power Systems -C.L.WADHAWA• www.scrib.com

Any queries