模拟换流阀长期运行工况的高压大功率晶闸管电热联合老化系统研制

Development of high voltage and high power thyristor electrothermal combined aging system simulating the operation condition of converter valve

近年来国内多个直流换流站发生严重事故,经调查发现事故起因多为长时间运行的换流阀晶闸管发生不同程度的老化甚至绝缘能力丧失。掌握晶闸管参数退化规律是开展晶闸管运维监测、预防此类事故继续发生的基础。因此为了深入了解换流阀晶闸管老化过程中特性参数退化规律与老化机理,首先需要搭建试验所需的模拟换流阀运行过程的晶闸管老化试验装置。文中首先分析了换流阀晶闸管的实际运行工况,并基于此设计了晶闸管电热联合老化主电路,接着对电路中涉及到的控制单元,包括绝缘栅双极型晶体管(IGBT)的驱动电路与晶闸管的触发电路进行设计与搭建,并基于晶闸管的实际运行工况设计了晶闸管结温控制系统。为了获得晶闸管老化过程中特性参数的退化规律,设计了晶闸管漏电流在线监测系统与反向恢复离线测量系统。经过检验,各个模块以及主电路均能够保持长期稳定运行,为换流阀晶闸管的老化试验打下了良好基础。

In recent years,serious accidents have occurred in many DC converter stations inland.It is found that the causes of the accidents are mostly the aging of the converter valve thyristor or even the loss of insulation.To master the law of thyristor parameter degradation is the basis to carry out the operation and maintenance monitoring of thyristor and prevent such accidents from happening again.Therefore,in order to deeply understand the degradation law and aging mechanism of the characteristic parameters of the valve thyristor in the aging process,it is necessary to build the thyristor aging test device required by the test to simulate the operation process of the valve.This paper first analyzes the converter valve thyristor’s actual operating conditions,and based on this the united thyristor electric heating aging main circuit is designed,then the circuit involved in the control unit,as well as the drive circuit of IGBT and thyristor trigger circuit are designed and build,and based on the actual operation condition of thyristor thyristor junction temperature a control system is designed.In order to obtain the degradation law of characteristic parameters during the thyristor aging process,the online monitoring system and the reverse recovery offline measuring system of thyristor leakage current are designed.After testing,each module and the main circuit can maintain long-term stable operation,which lays a good foundation for the aging test of the converter valve thyristor.