Aseminar on

DIGITAL TESTING OF HV CIRCUIT BREAKER

Submitted To: Submitted by: Ms.Shivani Johri Diksha Sharma Head Of Department 4th year, EE

Department of Electrical EngineeringSri Balaji Technical Campus, Jaipur

RTU, Kota February-2016

Content:-IntroductionNeed for testingTestings of circuit breakerDigital testingAdvantages &DisadvantagesApplicationsConclusions

Introduction:-A circuit breaker can make or break a

circuit, either manually or automatically under all conditions viz. no-load, full-load and short-circuit conditions.

The American National Standard Institute (ANSI) defines circuit breaker as: “A mechanical switching device capable of making, carrying and breaking currents under normal circuit conditions and also making , carrying for a specified time, and breaking currents underspecified abnormal circuit conditions such as those of short circuit”.

High voltage circuit breaker

Essential qualities of HV circuit breaker:-

In closed position they are good conductors.

In open position they are excellent insulators.

They can close a shorted circuit quickly and safely with out unacceptable contact erosion.

They can interrupt a rated short-circuit current or lower current quickly without generating an abnormal voltage.

Need for testing HV circuit breaker:-

When an overload or a short circuit occurs in the home or industry, the usual result is a blown fuse or a tripped circuit breaker.

Circuit breakers are mechanical devices, which are subject to deterioration due to wear, corrosion and environmental contamination, any of which could cause the device to remain closed during a fault condition.

Testing of circuit breakers:-Routine tests Type tests

Digital testing:-A project started with the following

parties :

KEMA high power laboratories The Netherlands.

Delft University of technology, TheNetherlands.Siemens AG, GermanyRWE Energy ,Germany

Aim of digital testing:-Developing digital testing of HV

circuit breakers. I.e. , a software product for testing a model of such a device , once its characteristic fingerprints are obtained from refined measurements during standard tests.

Digital offers a wide range of new possibilities for users , manufactures, standardizing bodies and test laboratories for fine tuning circuit breaker abilities in relation with standard and real power systems.

Advantages:-Evaluation of the relevance of future standards

for different circuit breaker technologies and extinguishing media.

Estimation of circuit breaker’s interrupting limit.Reduction of full scale testing in high-power

laboratories.Identification of network topologies that can

pose special difficulties to a circuitbreaker.Acceleration at development of new circuit

breaker design.Monitoring the aging process of circuit breaker

in service.Expansion of services for high-power

laboratories

Disadvantages:-Testing in costlierTesting is time consumingA tough procedure

Applications:-Influence of parallel capacitance

Table:- Influence for current

transformer

Current line length determination:-

Fig:- Current line length determination for digital testing

Conclusion:-Digital testing gives precise

information about the breaker, as obtained from laboratory tests.

This is useful for the development of future standards.

Powerful possibilities with digital testing are created when arc model and data analysis is coupled with a circuit analysis package.

The performance of a circuit breaker whose finger prints are obtained from real tests can be estimated in other circuits also.