| Because of the unbalanced distribution of natural resources and economic load centers in China,the power generation centers are far apart from the economic load centers.HVDC transmission has obvious advantages for this long-distance transmission situation and has become an integral part of the national grid interconnection.At present,China has formed a typical multi-infeed DC system in East China Power Grid and China Southern Power Grid,and will soon become the world’s most settled and most complex AC-DC power transmission system.AC and DC transmission systems have brought about outstanding voltage stability at the same time of flexible transmission and power transmission,and voltage collapse accidents occur at home and abroad.So,it is of great significance to study the method of evaluating the voltage stability of multi-infeed DC receiver systems.In this paper,starting with the evaluation criteria of voltage stability,The intrinsic mechanism,application scenarios and effectiveness of various voltage stability evaluation indicators for evaluating the voltage stability of multi-infeed DC receiver systems are studied.First,The relationship between the short circuit ratio index and the maximum power curve is analyzed.From the singular angle of the power flow Jacobian matrix of the multi infeed DC system,the relationship between the traditional single feed short circuit ratio and the multiple infeed short circuit ratio and the terminal voltage stability is theoretically analyzed and the application range of the voltage stability is evaluated.Second,The deviation characteristics between the generalized short circuit ratio and the multi infeed short circuit ratio are analyzed,and the accuracy of the voltage stability evaluation of the end-to-end system under the condition of asymmetric multi infeed DC is studied and its effectiveness is verified by simulation.Last,Through theoretical analysis,the factors affecting the generalized short circuit ratio are deeply studied.According to this,the variation law of the generalized short circuit ratio is given,and the conclusion of the analysis is verified by an example.The effect of reactive power compensation and reactive power consumption on voltage stability of converter station is studied and analyzed.A voltage stability evaluation index is proposed,which is based on reactive power compensation and reactive power consumption.That is,based on the generalized short circuit ratio,the effects of reactive power provided by reactive power sources such as AC filters and shunt capacitors at inverter side busbars and reactive power consumed by inverter stations are fully considered.A new evaluation indicator of the voltage stability of a multi-infeed dc receiver system is studied and defined—the generalized reactive effective short circuit ratio,According to the index,the criteria for dividing the system strength are given,last,the effectiveness is verified by simulation. |
PDF Full Text Request