With high voltage circuit breakers developing toward to higher voltage and larger current level,it is restrictive to set up the corresponding test equipments due to various conditions. Therefore, synthetic test (ST) has been rapidly developed around the world, and now it is the unique feasible method used for testing the breaking capability of super voltage circuit breakers (CBs). However, some disadvantages still exist. For example, it demands strict operating sequence and high accuracy among CBs during testing process, which means test will fail1 even little mismatch. In order to improve the success ratio of the tests, control system of synthetic test has been improved a lot in developed countries by improving the automatic level of control system. In recent years, some corresponding techniques have been introduced into several domestic testing laboratories. Whereas, for some technical reasons, experienced technicians are still indispensable to do some crucial calculations and operations manually during testing process, which may reduce the success ratio of the tests. As a result, a novel control system of synthetic test fully base on computer as center Is given in this artide, which improves the success ratio of the tests remarkably by raising automatic level of control system with cooperation of software and hardware.
In this artide, the fundamental and process of synthetic test will be analyzed first. structure of control circuit is set forth, and then time parameters of the tests are determined. Meanwhile, the design conception, algorithm, functions and structure about software of control system are introduced in details. Some problems emerging during on-site debugging will be discussed, and the corresponding schemes will be presented as well. Finally,some data about the system sampled during tests will be demonstrated.
The emphasis of our control system is software programming on synthetic test, besides, the design of corresponding measuring and controlling circuits are important of too. Python is adopted to program the whole software with assembly language embedded. Among them, Python is adopted to code user program, in which user can set test parameters, select test type and test voltage level, determine channels whether active or not to output trigger pulse. Serial port communication function is also included. Assembly language is used to code bottom control program, which is in charge of operating sequence of the CBs in main circuit according to the parameters set in user program.
After running for years ,the result indicates that the control system of synthetic test presented improves the quality and success ratio of test remarkably,which can turn arc prolonging circuit and high voltage circuit on in time according to test demands 〔20µs～2ms) , Meanwhile, thanks to the present functions especially high anti-interference ability, the system runs steadily and reliably with high degree of accuracy．