可控换相换流器耗能模式工作原理及电气建模

Controllable line-commutated converter (CLCC)has the controllable switching-off capability and can eliminate commutation failure caused by the single-phase grounding fault of AC system; however, during the fault period, the DC transmission power will still drop. Therefore, this paper presents the working principle of energy consumption mode in which CLCC main arrester and V13 sub-valve arrester act as energy consumption resistors, the nonlinear time-varying voltage source model of valve arrester is established and the electric equation of CLCC working circuit under energy consumption mode is solved. Moreover, the influence law of residual voltage value of V13 sub-valve arrester and early closing time of valve on energy consumption power is determined,and the DC system simulation model with closed-loop control strategy that can maintain the transmission power of the system at a constant value is established. It is proved that CLCC acts as a DC energy consuming device while playing the role of converter, the power that can not be absorbed by the AC system of the inverter station can be consumed by CLCC, the DC power of the system will not fluctuate, and the impact of the single-phase grounding fault of the AC system of the inverter station on the DC system can be minimized.