STUDY OF 220KV SWITCH YARD

Batch Members KATTA NARESH 08NA1A0225 KUMPATI VASU 08NA1A0229 N.HARISH SAGAR 08NA1A0238P.MANI KUMAR 08NA1A0244 S.T.KUMAR 08NA1A0250 V.NARENDRA BABU 08NA1A0253

INTRODUCTION OF VTPS

• 1. INTRODUCTION OF DR.NTTPS (VTPS)• Food, clothing and shelter were the basic needs of mankind till

lately but now we can say electricity has become a part of basic needs. Life without electricity has become unimaginable. There are three ways for the generation of electricity thermal, hydel under nuclear. In India, majority of the power is produced utilizing thermal energy

• Dr. N T T P S came into existence in 1977 in between Ibrahimpatnam & Kondapalli villages. It is unique in its layout and numerous authors expects such as easy operation and maintenance. There are three stages in Dr.NTTPS the total capacity of the three stages her is 1260MW.

• This report gives a detailed report about the various equipment and their working in the switch yard

SWITCH YARD: INTRODUCTION The system in the 220KV switch yard at VTPS receives electrical power

from 6*210 MW and other inflows like, Bheemadole (100 MW),Kothakota and LANCO (200 MW), via incoming transmission lines and delivers electrical power via the outgoing transmission lines to varies substations namely

Podili(2) Tallapalli(2) Nunna (2) Tadikonda (2) Kondapalli (2) Gunadala (1) Bheemadole (1) Vijjeswaram (1) Narketpalli (1), and Chilakallu (1). Though the generation at VTPS is 1260 MW, only 1200 MW will tag on to

the switch-yard.The rest is utilized for auxiliary consumption.

KONDAPALLI S.S

VTPS 2 FEEDERS

LANCO

132 VJW 132KV FEEDERS

EQUIPEMENTS IN SWITCH YARD

An electrical substation is an assemblage of electrical components including

bus bars Isolators circuit breakers transformers lighting arresters instrument transformers….etc.

The switch-yard comprises of the following equipment:

• 28 bays which include 6GTs,5 STs, 2 bypass, one bus coupler and 15 feeders.

• Station battery system.• Centralized air conditioning system with

connecting switchgear.

INSULATORSo The flexible ACSR conductors of transmission line and substation bus burs are supported

on string insulators. The rigid tubular bus bars in SS are supported on Solid insulators/post insulators.

Materials used for insulatorso Ceramic (Porcelain, Steatite)o Glass-fiber reinforced epoxy resin rod covered by sheds made of silicon-rubber)o PROPRETIES OF INSULATORS:o High Electrical resistance of insulator material in order to avoid leakage currents to

earth.o High Mechanical strength to with stand conductor load, wind load etc.’o It should be non porous and free from impurities and cracks.o High ratio of puncture strength to flashover.

• Three distinct types of Insulators are used in transmission systems and substations:• String Insulators (Suspension or tension) for supporting ACSR or AAAC conductors. The string

insulator consists of several identical Ball and socket type disc insulators in series with end fitting on across arm side and conductor side.

• a) Solid post insulators. Are used in the following applications and named accordingly.• Post Insulators for support• Shaft insulators• Operating rod insulators• Hollow porcelain insulator for transformers bushing, SF6 GIS bushing, CTs, CVTS, PTs, CBs

chambers.• • For DISTRIBUTION NETWORKS & SS:• Pin type insulator (for LT & HT)• Shackle insulators• Safety insulators• The important requirement of air-insulation and porcelain insulators in EHV substations and

transmission lines are

BUS BARS

• The choice of the bus bars scheme for a substation depends upon the degree of reliability and economic justification. The degree of reliability is evaluated by determining the continuity of service and possible faults.

TYPES OF BUS BARS ARRANGEMENTS:

SINGLE BUSBAR ARRANGEMENTSSSSSSSSI

This system is used for 132 KV substations. It is cheapest among all the others bus bars. It is totally shut down in case of a fault.

DOUBLE BUS BARS:• This system is costlier then a single bus bars system. One bus

can serve as reserve, which is used during maintenance or fault. It is used for 220 KV sub stations.

DOUBLE BUS BAR WITH TRANSFER BUS • This system has additional flexibility for operation. We can

take shut down on a breaker without interrupting the transmission line. It is used for critical 220KV substation.

CIRCUIT BREAKERS

• Circuit breaker is automatic switching device which can carrying normal current and switching in & out normal loads• Interrupt short circuiting currents• Able to performer auto reclose duty.• Classification of Circuit breaker:• Based on VOLTAGE• Low-less than 1kv• Medium-1kv to 52kv• High/Extra High-66kv to 765kv• Ultra High-above 765kv

• Based on LOCATION • Indoor• Outdoor• Based on INTERRUPTING MEDIUM• Air break………Air break Circuit breaker…………(ACB)• Air blast………Air blast Circuit breaker…………..(ABCB)• Bulk oil………….. Bulk oil Circuit breaker……….(BOCB)• Minimum oil………..Minimum oil Circuit breaker………….(MOCB)• SF6 gas insulated…………….SF6 Circuit breaker• Vacuum…………… Vacuum Circuit breaker………………(VCB)• Selection of a CB depends on:• Type of application • Rated voltage, current• Its breaking capacity(fault level of the installation)• Auto-reclose duty cycle•

SF6 CIRCUIT BREAKER

Opening operation:• Opening is affected by pulling the insulating rod (201), piston rod

(111), puffer cylinder (110) moving contact, moving arc contact (107) and the nozzle (105).After contacts wipe the stationary and moving and contact (104), (107) separate, there by generating arc. During down ward movement the gas in puffer chamber builds up and high pressure gas flows through nozzle and quenches the arc.

Closing Operation:• In closing operation, insulating rod (201) is pulled up and the

parts move in the reverse direction of opening operation. And also SF6 gas taken in to puffer chamber.

NAME PLATE DETAILS• RATINGS• Type 200-SFM-40A• Rated Voltage 245kV• Rated Insulation Level 1050kVp• Rated Frequency 50Hz• Rated Normal Current 3150A• Rated Short Circuit Breaking Current• R.M.S Value for A.C Component 40kA• Percentage D.C Component 50% • Rated Short Circuit Making Current 100kA• Rated Break Time 60ms (3 cycles)• Rated Short time Current 40kA for 3 Sec.• Operating Sequence 0-0.3S-CO-3 min co• Rated TRV 364kVp• Operating Mechanism Spring closing• Pneumatic tripping • Operating Pressure (air) 16.5kg/cm2 • SF6 Gas Pressure 6.0 kg/cm2 at 20c• Applicable Standard IEC-62271-100• Opening Time 30ms• Closing Time 100ms • Pole Discrepancy (Between Poles) 3.3ms • The center to center distance between phases is generally 4500mm.but cab\n be changed to suit users specific requirement

ADVANTAGES OF SF6 CB• Mostly widely used in EHV application• Low operating noise• Simple construction & compact size• Easy installation, inspection & maintenance.• SF6 is identified as a green house gas.

INSTRUMENT TRANSFORMERS

INSTRUMENT TRANSFORMERS:• Current transformer• Potential transformer

• Current transformer: Current transformer are used for supplying the current circuits of indicating instruments (ammeters, watt meters etc) recording meters (energy meters etc) and protective relays.

• CT is ideally a short circuited transformer where the secondary terminal voltage is zero, and the magnetizing current is negligible.

• Ip*Np =Is*Ns• Ratio error• Phase angle error• Composite error

CURRENT TRANSFORMER

VOLTAGE TRANSFORMER:• These instrument are used for supplying the voltage circuit of indicating

instruments, meters, and protective relay.• All voltage transformer are designed for a standard secondary voltage of

110v, 110/1.732 (63.5)• For voltage transformers at the following is valid:• Ep/Es=Np/Ns• Actual voltage ratio =Primary volts/secondary voltsVoltage transformer errors:• A) voltage ratio error• B) Phase angle error.• The errors at which the VTs operate depend on its burden and primary

voltage

POTENTIAL TRANSFORMER

POWER LINE CARRIER COMMUNICATION (PLCC)

PLCC is economical and reliable method of communication system.• The Equipment in a PLCC system are :• 1. Trap (Wave trap)• 2. Coupling capacitor• 3. Earth switch• 4. Drainage coil• 5. Lighting arrester• 6. Line matching unit • Carrier wave in PLCC is radio frequency waves of frequencies between

20KHZ to500KHZ.

PLCC SCHEMATIC DIAGRAM

ADVATAGES OF PLCC

Because of thick lines, attenuation of signal is less.Leakage of signal is negligible as lines are insulated

with H.V string insulators. It is economical, as the same power line is used for

communication, without additional cable.Disruption is less.Corona ring provided to maintain the RIV voltage

levels low and within specified limits.

TASKS OF THE SWITCH YARD: A). Protection of transmission system (To isolate faulty

network from the healthy one). B). Controlling the exchange of power (i.e.to control the

power transmission to load points as per requirements).C). Maintain the system frequency within targeted limits (this can be done by rising /lowering of generation or load scheduling)D). Determination of power transfer through transmission lines.E). Fault analysis and subsequent improvement

CONCLUSION

This project ‘’OVER ALL EQUIPMENT OF 220KV SWITCH YARD IN DR.NTTPS” is constructed in such a way that every one can understand about the working and principle of 220kv switchyard equipments. This also explains about battery system used as secondary purpose.

Further automatic devices can be provider to insulators like automatic OFF if insulator and giving the signal etc.

ANY QUERIES?

THANK YOU