Research On Three Phase Synthetic Testing Methods Of Circuit-breaker Having 3 Poles In One Enclosure

This paper introduces a three-phase synthesis testing method to detect the circuit breaker having 3 poles in one enclosure with no earthed neutral system. Because the gas-insulated metal-enclosed switchgear (GIS) has the virtue of small cube, long maintain periodic, few workload, safe and reliable operation and so on, it is greatly promoted. GIS has two kinds of three poles in one enclosure and three poles in different enclosure. Because the three-phase arc extinguish chamber of circuit breaker having three poles in one enclosure is set in the same tank which is connected with air and they effect each other during breaking, the single-pole test can't verify the performances. So the three-phase test must be done. The circuit-breaker with large capacity must be tested by three-phase synthesis-test.At first the paper analyses the breaking condition and three-phase short-current test method of circuit breaker having three poles in one enclosure, and do the theory analyses and comparisons of the basic principle and the working process of three-phase synthetic test in domestic and overseas laboratories. On the base of this and combine with the main test equipments, control and measure equipments, test place and other specific condition of this test, the double parallel current of this test which is leaded into the three-phase synthetic test is confirmed. The selection of current source and voltage source components, the sync control method of test, the measure requirements, the over-voltage protection and so on are introduced in details. The analysis and solution of the test control and the over-voltage condition are also given in the paper.On the basis of theory analysis and according to the IEC and TRV of GB, the voltage source parameters of the first and last-pole-to-clear, the requirements of the test task control and sync control, the protection method of over-voltage are decided, and the test equipments is selected, and the arc prolonging circuit is designed. The detailed scheme of the three-phase synthetic test condition in this laboratory is provided in this paper which establishes the theoretic basis for test condition.