Study on switching transients of cable collector system in wind power plant

The switching surges of a cable collector system can cause equipment failure in a wind power plant (WPP). The study on the switching over-voltage caused by operation of medium voltage breaker in the cable collector system is important. In this paper, a laboratory test system was set up to reproduce a part of a cable collector system in a WPP. Based on the way the load was connected to the cable collector, four test approaches were proposed to measure the switching over-voltage. A vacuum circuit breaker (VCB) with point on wave control was used in the circuit to study the effect of current chopping characteristics while breaking the inductive load. These switching tests were conducted to simulate the possible switching operations in a WPP. The test results have shown that the over-voltages caused in a cable system are closely related to the cable length and inductive load. The maximum over-voltage was observed during the breaking of the inductive load at zero phase voltage in which multi re-ignitions of the VCB were recorded.