大电网在线动态安全评估系统电网模型特性分析

摘要

总结了目前大电网在线动态安全评估数据中电网模型的两个特点，即负荷挂在220 kV母线及将主变高压侧为110 kV的发电机（简称110 kV发电机）等值成恒阻抗负荷。论证了这种特征对几种分析计算的影响：大扰动动态稳定性分析结果的变化随故障位置、电网状况不同改变；消除了小扰动稳定分析中与110 kV 发电机相关的振荡模式；基于方案方式的短路电流计算值偏小；负荷等值使基于潮流的短路电流计算值偏大，发电机等值使基于潮流的短路电流计算值偏小。结论的有效性用电力系统分析综合程序（PSASP）在华中电网数据上进行了验证。%Two main characteristics of grid model in data of on line dynamic security assessment system for bulk power system are pointed out, which include loads hanging on 220 kV buses and equating generators, in which booster transformer’s highest voltage level is 110 kV, (110 kV generators for short), into load of constant impedance. Their impacts on the following analysis and calculation are expounded and proved. It is found that the dynamic stability of large disturbances varies with the fault position and grid's status, the oscillation mode related to the 110 kV generators is eliminated in the small signal stability analysis, and the calculation value of short-circuit current is smaller based on the style of case, but for the calculation value of short-circuit current based on the power flow, it is larger due to loads equivalents while smaller due to generations equivalents. The conclusions are validated by operation data of Huazhong grid with Power System Analysis Software Package (PSASP).