溪洛渡—浙西±800kV特高压直流输电工程受端电网直流偏磁治理

DC Bias Suppression of Receiving-end Power Grid in ±800 kV Xiluodu-Zhexi UHVDC Project

针对±800 k V溪洛渡—浙西(简称溪浙)直流工程对浙江电网直流偏磁的影响,开展了受端电网直流偏磁研究。根据浙江电网拓扑结构与广域大地模型,基于场路耦合的方法建立了溪浙直流受端电网直流偏磁仿真模型,并通过测试结果验证了模型的准确性。针对浙江电网的特点,提出直流偏磁的治理思路,确定了500、220、110 k V变压器的直流偏磁治理标准分别为20、15、10 A。通过多次仿真与试验修正,提出了电容电阻结合、分阶段递进式的直流偏磁治理方法。经过3个阶段,对46座直流偏磁超标的变电站进行了治理,有效的抑制了浙江电网的直流偏磁水平。

In order to solve the Zhejiang power grid＇s DC bias induced by ±800 kV Xiluodu-Zhexi （Xizhe） UHVDC project, we studied the DC bias problem of receiving-end power grid. According to the topological structure of Zhejiang power grid and wide-earth model, a DC bias model of Xizhe HVDC receiving-end power grid was established based on field-circuit coupling method, and test data verified accuracy of the model. According to the characteristics of Zhejiang power grid, DC bias suppression guideline was introduced, 500, 220 and 110 kV transformer＇s tolerated DC bias currents were limited to 20, 15 and 10 A, respectively. Through multiple simulation and test modification, the capacitance-resistance combined and stage by stage DC bias suppression strategy was proposed. Through 3 stages, 46 over standard substations were treated, and the DC bias of Zhejiang power grid was restrained in lower level.