风电场电缆集电网操作过电压的模拟试验和暂态分析

Simulating Experiment and Transient Analysis on Switching Surges in Cable Collection Grid of Wind Power Plant

为了解决大型风力发电场中压电缆集电网系统的暂态过电压防护及绝缘配合问题以提高风电场运行的安全可靠性,搭建了风力发电场中压电缆集电网系统的实验室模拟试验平台,并建立了相应的电磁暂态分析模型,研究了真空断路器的操作在风电场中压电缆集电网系统中产生的暂态过电压的特性。采用永磁操作真空断路器的选相位技术来测量最大操作过电压水平,得到了操作过电压水平与电缆长度、感性负载和断路器动作相角的密切关系。模拟试验结果表明,短电缆和大感性负载时开断断路器会产生最高的过电压,真空断路器发生重燃现象时过电压标幺值可达5。模拟200 MW风电场的暂态仿真分析表明,重合闸操作可产生最高2.4的过电压标幺值。

To improve the safety and reliability of large wind power plant （WPP）, the switching over-voltage protection and the insulation coordination in cable collection grid is essential. Thus we set up a typical laboratory test system and es- tablished numerical models to facilitate computer electro-magnetic transient analysis for the real system. The characteristics of transient over-voltages （TOVs） in cable collection grid due to operations of vacuum circuit breaker （VCB） were studied. Based on phase switching controller of VCB with permanent magnetic operating mechanism, the highest TOV was measured. It is found that TOVs is closely related to cable length, inductive load, and operation phase. The experimental results show that the highest TOV occurs in the case of switching off transformer with the short cable and large inductive load, and its per unit overvoltage may reach 5 when there are re-ignitions of VCB. The transient anal- ysis of a real cable collection grid of 200 MW WPP shows that the highest per unit switching overvoltage may reach 2.4 during VCB＇s re-closing.