750 kV线路保护与并联电抗器动作的研究

Study on the Performance of Protective Relaying and Shunt Reactors of 750 kV Transmission Line

分析了并联电抗器在750kV输电线路单端电源供电与双端电源供电情况下抑制过电压的作用;同时分析了当750kV线路输送大功率时,由于并联电抗器的接入又导致线路电压显著降低,线路的传输能力受到限制,因此应当考虑在传输大功率的运行方式下切除并联电抗器。为解决线路传输能力与抑制过电压的矛盾,分析研究了并联电抗器在抑制750kV线路跳闸过电压、加速潜供电弧熄灭以及抑制合闸过电压等方面的作用,并由此提出了750kV线路保护与并联电抗器之间动作配合关系。理论分析与仿真研究表明,所提出的线路保护与并联电抗器之间的动作逻辑关系不仅保证了750kV输电线路正常经济运行,又达到了并联电抗器抑制过电压等方面的作用。

This paper analyzes the effects of shunt reactors for restraining over-voltage in the case of 750 kV transmission line with one-terminal or two-terminal power supply. When heavy load is transmitted along a 750 kV transmission line, the connected shunt reactors can lead to big voltage decreasing, so transmitting capacity of line is limited greatly. Accordingly, it is necessary to consider that shunt reactor should be cut off in the operation mode of heavy load. This paper analyzes the roles of shunt reactors in constraining tripping over-voltage of 750 kV transmission line, accelerating arc extinguish and constraining reclosing over-voltage etc. In order to solve the contradiction between the increasing line transmitting capacity and constraining over-voltage, this paper proposes a novel action cooperating scheme of line protection and shunt reactors. Theoretical analysis and simulation tests show that the proposed action cooperating scheme not only insures the normal and economic operation of 750 kV transmission line, but also achieves the role of shunt reactors to compress over-voltage etc.