柔性直流电网故障电流主动控制典型方案综述

Overview on Typical Schemes for Active Control of Fault Current in Flexible DC Grid

柔性直流电网网架结构与运行方式多样,多种电力电子设备之间存在强耦合关系,其故障特性复杂,协调控制困难,对故障电流进行积极主动的控制仍然面临着很大的挑战。文中基于柔性直流电网故障电流发展机理,对交直流电网故障特性做了对比和总结,说明了柔性直流电网故障电流主动控制的必要性和可能性;确定了柔性直流电网故障电流主动控制方案的基本原则;总结了国内外研究成果,根据选择性原则和抑制原理对主动控制方案进行了分类;以几种典型方案为例,分析了不同类型主动控制方案的特性,并在PSCAD/EMTDC中进行了仿真验证,对不同主动控制方案的特性进行了对比和总结。结果表明,通过源侧和网侧设备协同配合进行故障电流的主动控制,能够快速隔离故障,节约线路投资成本,具有快速恢复能力。

The structure and operation modes of flexible DC grid are diverse, and there are strong coupling relationships among various power electronic devices. The fault characteristics are complex, coordination control is difficult, and active control of fault current still faces great challenges. Based on the development mechanism of fault current in flexible DC grid, this paper compares and summarizes the fault characteristics of AC and DC grids, and illustrates the necessity and possibility of active control of fault current in flexible DC grid. The basic scheme of active control scheme for fault current of flexible DC grid is determined. Domestic and foreign research results are summarized, and active control schemes are classified based on selectivity principle and suppression principle. Taking several typical schemes as examples, the characteristics of different types of active control schemes are analyzed and simulated in PSCAD/EMTDC, and the characteristics of different active control schemes are compared and summarized. The results show that the active control of fault current coordinated by the equipments on both source side and grid side can isolate fault quickly, save the cost of line investment and recover from fault rapidly.