Researches On The Quantitative Indexes In Multi-infeed HVDC Systems

As a key quantitative indicator for evaluating the relative strength of AC systems insingle-infeed direct current systems,the short-circuit ratio is widely used.But it is notapplicable to multi-infeed direct current systems any more. Therefore, giving thereasonable definition of the multi-infeed short-circuit ratio is very necessary.At present,in academic circle there are two calculation methods about multi-infeed short-circuitratio,that is,short-circuit impedance method and multi-infeed interation factor method.In the paper,by exploring the origin the theoretical analysis and formula derivation oftwo methods are done.On this base,the unity of two methods are proved,and theunderstanding mistake in the short-circuit impedance method is pointed.A three-infeeddirect current system model is built by remaking the system of 3-machine and 9-bus inBPA.In this model,simulation analysis are made,which prove the consistency of twomethods.In addition,the conclusion of multi-infeed short circuit ratio is less thansingle-infeed short circuit ratio is drawn.