Control Principle and Protection Analysis of the HVDC Open Line Test
The HVDC open line test is a means of detection which a DC voltage is presented to the DC side of a converter station to test the insulate level, and the related control and protection philosophy is entirely different to the normal operation. If the control and protection is abnormal, the DC voltage will be elevated abnormally or remained unchanged, eventually lead to the test failed. Combined with the conventional DC system open line test, the control principle of open line test is described, and the difference of bus voltage is not more than 10 kV by comparison of theoretical calculation and actual engineering. It is derived that the DC line vohage reference value and the actual voltage measured value can synchronize change. In order to ensure the equipment's security the convertor will be blocked if the test is unsuccessful, control and protection technologies such as the voltage difference protection, overcurrent protection, overcurrent backup protection and protective trigger are used in the ABB company's Mach2 system. Differences are drawn: the principle, the control, the protection of the normal operation of the DC system and the open line test.
High voltage DC lineDC poleOpen line testProtective triggerTriangle wave
NETL
NSTL
万方数据
