基于实测数据的负荷频率参数辨识及影响分析

特高压直流受端电网中,换流站闭锁故障可能引起交流系统频率大幅波动,其中负荷的频率特性对系统频率响应具有重要影响。首先,分析了采用电力电子接口的新型负荷设备频率特性,以及当前此类负荷设备比重不断增加情况下负荷总体的频率特性变化趋势。然后,基于华东电网直流闭锁故障的实测数据,分别对节点和全电网的负荷频率模型进行了拟合,得出了负荷总体频率响应特性变弱的结论。最后,采用华东电网算例对实测模型与原有模型进行了对比仿真,验证了原有负荷频率模型偏于乐观。

Frequency Parameter Identification and Impact Analysis of Load Based on Measured Data

In a receiving power grid with ultra-high voltage direct current,the block fault in an inverter station may cause large frequency fluctuations,in which the frequency characteristics of load play an important role in the frequency response of the system. First,the frequency characteristics of new types of load equipment with power electronic interface are analyzed,and the trend of frequency characteristics of the total load is studied under the assumption that the proportion of this type of load equipment increases continuously. Then,based on the measured data from East-China power grid under DC block fault,the frequency models of load on the bus and the whole grid are fitted,respectively, and it is concluded that the frequency response characteristics of the total load are becoming weaker. Finally,the measurement model and the original model are compared and simulated with East-China power grid as a numerical example,which verifies that the original load frequency model is prone to be optimistic.