When the AC collection system of the renewable energy connected to the converter station fails,the converter station is very prone to overcurrent locking and cannot realize the low-voltage ride-through(LVRT).Based on the analysis of the coupling mechanism and the characteristics of the power exchange devices at both ends,the problems existing in the power exchange system are first analyzed on the basis of the superposition of these devices.Then,an LVRT method based on the active step-down control is proposed.By monitoring the local output current of the converter station,the dynamic adaptive selection of the step-down amplitude is realized.At the same time,the LVRT boundary conditions characterized by the AC current are set.Finally,the problem of overcurrent locking of the converter station during the LVRT is solved.A refined model of the AC collection system with renewable energy connected to the converter station is built in the PSCAD,and the effectiveness of the proposed control method is verified by simulation.
关键词
分段降压/VF控制/汇集系统/低电压穿越
Key words
active voltage reduction/VF control/collection system/low-voltage ride-through
维普
万方数据