基于数字混合仿真的电网一次时间常数计算方法

A Calculating Method for Primary Time Constant of Power Grids Based on Digital Hybrid Simulation

电网一次时间常数是决定非周期分量衰减快慢的因素,准确计算电网一次时间常数是开展电流互感器暂态特性分析的重要前提。利用电力系统全数字仿真装置的混合仿真功能,提出了一种准确计算电网一次时间常数的方法。通过对全系统机电暂态建模及局部电网电磁暂态建模,获取不同运行方式下的短路电流,滤波后得到短路电流的非周期分量,最终求得电网一次时间常数。仿真结果表明,所提出的算法具有较高的计算精度。

The primary time constant of power grids is the major factor of determining the decay rate of non-periodic components.Accurate calculation of the primary time constant is the important premise of transient characteristic analysis of current transformers.Based on the hybrid simulation function of the advanced digital power system simulator,an accurate primary time constant calculating method is proposed.By developing the electromechanical transient model of the whole system and electromagnetic transient model of the local grid,short-circuit current in different operating modes is obtained.After filtering,the non-periodic component of short-circuit current is obtained and hence the primary time constant.Simulation results show that the algorithm has fairly high accuracy.