交直流电网故障暂态功率倒向解析

针对交直流电网出现的暂态功率倒向现象而导致继电保护误动的问题,从继电保护的视角出发,在电磁暂态时间框架下研究交直流系统相互影响机理和交流故障特征的变异机理,提出在换相失败电磁暂态过程的解析分析、特征变异对保护性能的影响评估方法和评价指标,进而给出了交直流混合电网界定暂态功率倒向的计算模型和方法。交直流系统相互作用而引发的暂态功率倒向是由交流故障和直流系统快速变化引起的2个不同扰动源同时作用于电网元件,且满足一定电气和时序条件下"竞争"的必然结果。仿真结果验证了所述模型和方法的正确性。

Transient Power Converse in an AC/DC Interconnected Power Grid

In view of the transient power converse leading to the malfunction of the protective relay in the AC/DC power grid,the mechanism of interaction of AC/DC systems and the change of AC fault features are studied in the electromagnetic transient time framework from the viewpoint of protective relaying.The HVDC commutation failure is analyzed.The evaluation method for and indices on the influence of the resolving analysis and fault feature variation on the protection performance are proposed in the electromagnetic transient process of commutation failure.Then the method of calculating the boundary of the transient power converse is presented.The transient power converse occurring in the AC/DC power grid is an inevitable result of electric competition and time sequence competition between the disturbance due to AC fault and that due to the rapid response of HVDC.Simulation results show the validity of the model and method proposed. This work is supported by National Natural Science Foundation of China(No.50807017) and the Fundamental Research Funds for the Central Universities.