Auto Reclosure Ppt

Auto-Reclosure

Overview • • • • • • • • • • •

History Introduction What is Auto-reclosure……….? An Over head line with Auto recloser relays An Over head line without Auto recloser relays Basic Requirement of Autorecloser Relay Performance Typical site tests items of autorecloser relay. Salient features of Auto-reclosure. Advantages of Auto-reclosure Conclusion References

History • Automatic reclosing was first Applied in the early 1900 radial feeders protected by instantaneous relays and fuses. • By using Auto reclosurer circuit upto 88% success • . High-speed reclosing (HSR) was first used by American Electric Power System in 1935 • If this high-speed reclosure was successful, the remaining terminals were reclosed with time delay to complete the through circuit

Introduction • Autorecloser relays are widely implemented in the electric utilities Over Head Lines networks to improve power availability and to maintain system stability. • Site testing need to be performed before operation to ensure proper function of Autoreclosers. • There is not much manufacturer guidance in functional site testing of Autoreclosers. Therefore, testing engineers have to carry out the functional site tests according to specific requirements of the installations. • Application of multifunction and numerical relays has reduced the number of elements and wirings to be tested on site, but it would not eliminate the requirement to perform site testing.

What is Auto-reclosure………? • CB make one attempt to reclose after tripping to clear fault. • Results:• Successful • unsuccessful

An Over head line with Auto recloser relays

1. A temporary fault occur 2. Protective relays operate Utility Substation

– breaker tripped – Power off

Customers

3. Fault extinguished 4. Autorecloser relays order the breaker to reclose – Breaker reclose – Power is restored automatically

Riam A. Wibowo

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An Over head line without Auto recloser relays

Utility Substation

1. A temporary fault occur 2. Protective relays operate – breaker tripped – Power off

Customers

3. Fault extinguished 4. Breaker need to be closed manually to restore power

Riam A. Wibowo

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The most important parameter of an Auto-reclosure • Dead time:- Time between the fault arc being extinguished and the circuit breaker contacts remaking. • Reclaim time:- The time from the making of the closing contacts on the auto-reclose relay to the completion of another circuit within the auto-reclose scheme which will reset the scheme • Number of shots:-The number of attempts at reclosing which an auto-reclose scheme will make before locking out on a permanent fault.

TYPICAL CONFIGURATION & SETTING of AUTORECLOSER RELAY in INDONESIA 500kV

150kV

20kV

0.7 or 0.9 second

1 second

60 second

Reclaim Time Setting

40 second

40 second

180 second

Number of shots

single shot

single shot

single shot

single pole

single and three poles

three poles

Dead Time Setting

Single or Multi Pole

275kV

• • Number of Breakers Protective relay

two Distance Relay

One two (for “One & Half Breaker” S/S) Distance Relay

Riam A. Wibowo

one Over Current

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Basic Requirement of Autorecloser Relay Performance

 The Autorecloser Relay should reclose the Breaker(s) whenever it is initiated by Protective Relay  The Autorecloser Relay should not reclose the Breaker(s) if the initiation occurs during the Reclaim Time  For single pole mode, the Autorecloser Relay should only reclose the Breaker(s) for single phase to earth fault.  The Autorecloser Relay should never reclose the Breaker(s) if :  

no initiation from Protective Relay (e.g. when the Breaker(s) are intentionally opened by people) Any of the Breaker(s) is not ready it is not switched to active

For single and three poles mode : The Autorecloser Relay should reclose the Breaker(s) for line-line fault under control of synchrocheck relay. The Autorecloser Relay should reclose the Breaker(s) for single phase to earth fault. Three poles reclosing should be under Synchro Check control (except for 20kV radial networks). Failure of reclosing after single pole tripping should be followed by tripping of all poles.

Specific requirement for 500 kV Autorecloser Relay

• The Autorecloser Relay should reclose the Breaker(s) when initiated by any Distance Relay (due to duplex configuration of 500 kV protection scheme)

• Since 500kV Substations are one & half breaker type, the Autorecloser Relay should be able to recognize and control each of the Breaker as “leader Breaker ” and “follower Breaker”

TYPICAL SITE TESTS ITEMS OF AUTORECLOSER RELAY Visual Check

INSTALLATION

Check of the Power Supply

Test of the Autorecloser settings

Functional Testing (involving operation of Protective Relays & Circuit Breaker(s) Riam A. Wibowo

OPERATION

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Salient features of Auto-reclosure • Used as pole mounted application or as an Auto-reclosure. • Highest degree of personal safety and protection. • Convenient operation modes like RTU or MAN. • Highest fire retardant. • Easy and convenient installation.

Advantages of Auto-reclosure • • • • • •

Improved reliability of supply Better customer service Improved customer satisfaction Reduction in duration of break down time. Better quality of supply. Quick restoration of power supply in case of temporary faults • Easy identification of faulty section. • Taking LC (Line clearance) is easier due to Online switching operations • Improvement in performance of various reliability indices

Conclusion The benefit of this particular circuit breaker is by the way of improves. satisfaction and improvement in reliability indices. The benefits of this auto-reclosure are largely tangible. The important point for using autoreclosure is it reduces human effort. The fast, easy and less expensive to implement nature.

References • Aboreshaid, S.; Billinton, R. and Faried, S. O. (1998): Effect of Adaptive Single-Pole Reclosing on the Stochastic Behaviour • of Turbine-Generator Shaft Torsional Torques, IEEE Transactions on Energy Conversion • Aggarwal, R. K. (1998): Experience with Advance Adaptive Auto-Control Techniques for EHV Transmission Systems. • IEE, 1998 • IEEE Power Systems Relaying Committee; Automatic Reclosing of Transmission • Lines; IEEE Transactions, Vol. PAS-103, Feb. 1984 • Protection Relay Application Guide; GEC Measurements, 1975

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