换相电压简化计算模型及其在换相失败评估中的应用

基于准稳态公式理论计算的换相失败评估方法,无法精确评估换相失败边界附近的情况,而基于详细工程模型电磁暂态仿真的方式虽然精确,但效率低且工作量大.为了在兼顾精度的同时提升换相失败风险评估效率,基于等值网络的状态方程,文中提出了交流故障后直流系统换相电压的简化计算模型,并进一步应用计算结果进行换相失败风险评估.通过仿真软件PSCAD/EMTDC,从换相面积和换相失败评估结果两个方面,验证了计算模型的有效性.结果 表明,对于故障后首次换相过程而言,应用文中模型求得的换相面积与仿真所得换相面积相差甚小,且应用该模型能较为高效精确地评估直流发生换相失败的情况.

A Simplified Calculation Model of Commutation Voltage and Its Application in the Evaluation of Commutation Failure

The evaluation method of commutation failure based on the quasi-steady-state formula cannot accurately estimate the situation nearby the commutation failure boundary. And the method based on the electromagnetic transient simulation of the detailed engineering model is accurate, but the efficiency is low and the workload is large.In order to improve the efficiency of commutation failure risk assessment and take into account the accuracy, based on the state equation of the equivalent network, this paper proposes a simplified calculation model of the commutation voltage in the DC system after AC fault, and applies the calculation results to the risk assessment of commutation failure. Through the simulation software PSCAD/EMTDC, the validity of the calculation model is verified from two aspects: the commutation area and the evaluation results of commutation failure. The simulation results show that the commutation area obtained by the model is very close to the commutation area obtained by the simulation software in the first commutation process after the AC fault. And applying this model can estimate the situation of commutation failure with accuracy and efficiency.