摘要
青海750 kV电网官亭主变空载变压器合闸曾引起青藏直流双极闭锁事故,针对青海电网低次谐波传导机理与抑制措施开展了相关研究。首先计算750 kV官亭站与330 kV柴达木换流站之间的节点转移阻抗,判断出网架内存在二次谐振的风险;然后在EMTDC环境下搭建青海电网等值模型,对网架内各节点的背景谐波水平进行仿真,通过仿真结果与实测数据的对比,验证了模型的准确性;在此基础上根据合空变励磁涌流测试数据,在仿真模型中模拟官亭主变空载合闸引起青藏直流谐波保护动作的工况,确定了谐波传导至柴达木换流母线的放大水平;最后基于换流母线上出现的最严重低次谐波工况,提出了几类谐波抑制措施,并通过仿真评估了几类措施的抑制效果。
Charging no-load transformers in Qinghai 750 kV power grid has once caused blocking of Qinghai-Tibet DC system. Research is conducted focusing on low-order harmonics transmission mechanism and suppression measures in Qinghai Power Grid. First, according to calculation results of the transfer impedance from Guanting 750 kV station to Qaidam 330 kV converter station, it is estimated that the grid structure has risk of second harmonic resonance. Then Qinghai grid equivalent model is built with EMTDC, and validated by comparison of simulation results and measured background harmonic contents in the grid. Based on model and test data of magnetizing inrush current, the operating condition that Guanting station＇s main transformer charging led to DC harmonic protection＇s action is simulated and the increasing level of second harmonic content on converter bus is determined. Finally, on basis of the worst harmonic condition, several suppression measures are proposed and harmonic suppressing effects are evaluated.
出处
《电网技术》
EI
CSCD
北大核心
2015年第8期2277-2282,共6页
Power System Technology
关键词
青藏直流系统
2次谐波
转移阻抗
电网等值模型
励磁涌流
Qinghai-Tibet DC system
second harmonic
transfer impedance
grid equivalent model
magnetizing inrush current
