HVDC System Commutation Failure Transient Judgement Method

Abstract

In order to forecast the commutation failure of HVDC system, this paper analyzes the specific reasons for the rise of the direct current in the case of the receiving end failure of HVDC system and makes a quantitative analysis, It is found that the capacitance of direct transmission line discharging is the main factor of the increasing of the direct current during the initial stage, On the basis of two new physical quantities which are the variation rate of direct current and the variation rate of voltage of inverter AC bus, a new method using the variation rate is obtained to judge the process of commutation failed or not. Then in the PSCAD/EMTDC platform, the theoretical analysis results was verified, and they are close to the results of the simulation, The method mentioned in this paper can forecast the commutation failure, and it is beneficial to take measures in the near future.