Flexible Ac Transmission Equipment Current Test Methods

The trend towards ever-higher unit ratings for power electronics has been accompanied by enormous advances in semiconductor device. Also, these have led to a fast increase in specific power densities and many new areas of application. Therefore, demand for better system reliability and availability has become more intense. At the same time, high ratings make it almost impossible to test the equipment in the real system directly.Over current is one of the important faults with which FACTS valves and HVDC valves will meet in their operating. Manufactures of such valves must therefore verify that the components can withstand the calculated stresses under the fault conditions as close as possible to those experienced in service.The core of the equivalence mechanism for the over current test is finding an alternative test method to reproduce the stresses applied on the valves, which are equivalent with that in the real conditions by effect.Based on the analyses of the over current faults of valves in operation conditions, and the dynamic physical mechanism of over current stresses, this thesis bring forward an equivalence test theory. Especially, voltage and current stresses on the valves under five operational states are highlighted in this paper. Following, an equivalent test method and a scheme of the test equipment is advanced, which includes the function of the controlling, monitoring, protecting and measuring system.A model has been established and simulations are made in Saber environment, at the same time, a physical model is put up and some tests are made on it. All the results demonstrate the proper design of the test equipment and the test method.Finally, some proposal are brought up for the HVDC valve's fault current test,...