换相失败下直流控制参数对送端暂态电压影响机理分析

Influence Mechanism Analysis of DC Control Parameters on Transient Voltage of Sending System under Commutation Failure Condition

换相失败期间高压直流输电系统无功特性与控制参数密切相关,对送端系统暂态电压影响显著。首先阐述了换相失败期间送端暂态电压的形成机理,并指出故障期间暂态电压、直流无功特性与直流电流间的关系,进而提出一种建立直流电流方程来间接描述送端暂态电压的分析方法;然后,在此基础上,根据直流电流特性分阶段建立直流电流理论分析模型,通过分析控制参数对直流电流作用规律,进而揭示各控制参数对暂态电压的影响机理。最后基于PSCAD/EMTDC仿真平台对所得结论进行验证。

The reactive power characteristics of HVDC system is closely related to control parameters during commutation failure,significantly impacting the transient voltage of sending system.Firstly,the mechanism of generating the transient voltage of the sending system during the commutation failure is expounded,the relationship among the transient voltage,reactive DC characteristics and DC current during fault period is pointed out,and an analysis method of establishing the DC current equation to indirectly describe the transient voltage of the sending system is proposed.Then according to the characteristics of DC current,the theoretical analysis model of DC current is established in stages,and the influence mechanism of each control parameter on the transient voltage is revealed by analyzing the action law of the control parameters on DC current.Finally,the conclusions obtained are verified based on the PSCAD/EMTDC simulation platform.