220 kV单回长线切改中的高抗配置与工频谐振分析

为避免电网产生过电压，一般在长线路两端配置线路高抗。随着电网不断建设，往往会将长线路切改，接入新的变电站，以增强电网输送能力。在此过程中，因线路高抗配置不当引发的电网谐振事故频发。基于PSCAD软件，建立某220 kV单回长线路送出工程的精确电磁暂态模型，分析高抗及小电抗参数配置与工频谐振的动态特性，定量分析了线路对地电容、补偿度、中性点小电抗等因素与工频谐振之间的关系。最后，针对工程提出整改措施，并成功解决谐振问题，为电网的设计与运行提供技术参考与实践经验。

High Reactor Configuration and Power Frequency Resonance Analysis for The Cuting-Off of 220 kV Single-Circuit Long Line

In order to avoid overvoltage in the power grid, shunt reactor is usually installed at both ends of long lines. As the power grid construction is expanding, long lines are often cut off and new substations are connected into the grid in order to improve the transmission capacity of grid. In the process, resonant accidents caused by improper configuration of shunt reactor are frequent. Based on PSCAD software, the precise electromagnetic transient model of renewable energy transmission project through 220 kV single-circuit long line is established in this paper. The dynamic characteristics of power frequency resonance and the parameter configuration of the shunt reactor and a small neutral reactor are analyzed. The influence trend of line-to-ground capacitance, line compensation degree and neutral reactor with power frequency resonance are analyzed quantitatively. Finally, the resonance problem is settled successfully with the proposed method, which can provide technical reference and practical experience for the design and operation of power grid.