Reactive Power Distribution and Transient Overvoltage Calculation Method for the Multi-Outfeed DC System under DC Blocking
In response to the unclear mechanism of transient reactive power distribution and inaccurate calculation of transient overvoltage in the multi-outfeed DC transmission system under DC blocking,firstly,based on the multi-outfeed interaction factors,the reactive power distribution characteristics under the interaction of blocked DC and healthy DC are analyzed in depth to obtain the conclusion that the configuration of blocked DC reactive power,the number of DC out-feeds,and the interaction factors of multiple out-feeds feeds are the main factors affecting reactive power distribution.On this basis,taking the voltage coupling characteristics of the multi-outfeed DC transmission system into consideration,the transient overvoltage calculation methods are proposed for both locked DC and sound DC converter busbars under single DC blocking.Finally,based on the PSCAD/EMTDC platform and CIGRE DC transmission standard testing system,a double outfeed DC simulation model is established,and the simulation results of the model have verified the correctness of the transient overvoltage calculation method.The proposed method can provide important references for evaluating the stability of multi-outfeed systems,guiding protection measures,optimizing design and operation strategies,as well as planning and making expansion decisions..
multi-outfeed DC systemreactive power distributiontransient overvoltagemulti-outfeed interaction influence factor