混联半波长系统穿越站内交流母线故障研究

Study on a Hybrid Half-Wavelength System Crossing the AC Bus Fault in a Station

交直流混联半波长系统是解决半波长沿线供能的有效途径。当直流端站内的交流母线发生短路故障且故障不被及时切除,半波长交流系统沿线的工频过电压水平升高,会导致过压保护动作甩掉直流系统,直流系统阀侧还会受过电流冲击。本文提出在直流母线处接入限流模块的方法来限制故障电流上升速度,以此稳定直流电压,尽可能使交流系统在故障工况下能继续为直流系统供能,提高系统的故障穿越能力。最后通过仿真验证了该方法的有效性。

AC-DC hybrid half-wavelength system is an effective way to solve energy-supplying along half-wavelength.When there is a short circuit fault on the AC bus of the DC station and the fault is not removed in time,voltage along the AC system will increase and lead to the action of over-voltage protection and exitance of DC system.The valve of DC system will be also subjected to the impact of over-current.This paper proposes a method of accessing current limiting module at the DC bus to stable DC voltage by limiting the rising speed of the fault current.This way enables the AC system to continue to power the DC system under fault condition and improves the fault-crossing capability of system.Finally,the effectiveness of the method is verified by simulation.