Smart protection system for identification and localisation of faults in multi‐terminal DC microgrid
Smart protection system for identification and localisation of faults in multi‐terminal DC microgrid
复制标题
多端直流微电网故障识别与定位的智能保护系统
作者：
R. Chauhan;Kalpana Chauhan
：直流微电网提供水平基础设施来整合分布式发电（DG）和负载。与传统的交流系统不同，直流系统无法承受或承受高强度的故障电流。这使得故障定位变得非常困难。传统的保护技术使直流微电网中的直流链路完全断电。本研究提出了一种针对多端直流微电网线间故障和低电阻接地故障的新保护方案。该方案将故障区段与直流微电网隔离。环网直流母线系统中健康区段的运行不受任何干扰，并保持供电连续性。电流传感器安装在直流母线段上，以监测不同节点的输入和输出电流。进一步地，在市电两端还安装了电流传感器，以监测市电两端的电流差。控制器检测到该电流差并打开断路器。为了满足快速开断时间和高短路电流承受能力的要求，断路器采用绝缘栅双极晶体管。故障定位方案给出了各部分（服务干线）的故障位置以及微电网中的故障电阻。所提出的概念已通过计算机模拟得到验证。
: DC microgrid provides the horizontal infrastructures to integrate distributed generation (DG) and loads. Unlike traditional AC systems, DC systems cannot survive or sustain high magnitude fault currents. It makes locating faults very difficult. The conventional protection techniques completely de-energies the DC link in the DC microgrid. A new protection scheme for multi-terminal DC microgrid against line-to-line fault and the low resistance earth fault is presented in this study. The scheme isolates the faulted section from the DC microgrid. Healthy sections are operated without any disturbance and supply continuity is maintained in a ring main DC bus system. The current sensors are mounted at DC bus segments to monitor the entering and outgoing current at different nodes. Further, the current sensors are also mounted at both ends of service mains to monitor their current difference at both ends of the service mains. The controller detects this current difference and opens circuit breakers. To meet the requirement of fast interrupting time and high short-circuit current withstanding capability, insulated-gate bipolar transistors used as circuit breakers. The fault location scheme gives the fault location in various sections (service mains) and faults resistance in the microgrid. The proposed concepts have been verified by computer simulation.