Computer aided optimized design and simulation of synthetic test circuit for testing 800kV rating circuit breakers

Development in electrical power transmission system requires the use of circuit breakers with increasing breaking capacity. At present circuit breakers are to be installed on 245 kV to 1100 kV power system with short circuit ratings up to 120 kA. To test high voltage CBs, direct testing using the power system or short circuit alternators are not feasible. The testing of high voltage CBs of larger capacity requires very large capacity of testing station. To increase testing plant power is neither an economical nor a very practical solution. Synthetic testing is an alternative equivalent method for testing of high voltage circuit breakers and is accepted by the standards. This paper presents a TRV rating concepts, IEC standards TRV envelopes and types of synthetic test circuits and their comparison. Analysis and mathematical modeling of 4-parameters TRV synthetic test circuit is presented. In order to find the possible combinations of circuit components and to optimize the values of capacitance of capacitor banks for the desired frequencies of a particular rating of circuit-breaker, the program/software has been developed by using MATLAB and Visual Basic 6. Design and simulation of 4-parameters TRV synthetic testing circuit (Weil - Dobke type) is done by using PSIM simulator as per new TRV requirements given in IEC 62271-100 (2008). The circuit is designed and simulated for both terminal faults as well as short line faults test duty for 800 kV rating circuit-breakers.

I. Introduction

In synthetic testing, there are two sources of power supply for the testing.