Title: Application of Inverse-Time Overcurrent Protection Based on Low Voltage Acceleration in Micro-Grid
作者: 李永丽; 金 强; 李博通; 李中洲 天津大学智能电网教育部重点实验室，天津 300072
Author(s): LI Yong-li; JIN Qiang; LI Bo-tong; LI Zhong-zhou
Key Laboratory of Smart Grid of Ministry of Education，Tianjin University，Tianjin 300072，China
关键词: ; 分布式电源; 微电网; 低电压加速反时限过电流保护; 运行模式
Keywords: ; distributed generator; micro-grid; inverse-time overcurrent protection based on low voltage accel-eration; operation mode
分类号: TM773
文献标识码: A
摘要: 低压配网中用的反时限过电流保护(ITOC)由于分布式电源(DG)的接入及微电网运行方式变化的特殊性从而不能满足选择性和速动性的要求．为此，基于分布式电源和微电网的运行及故障特征，提出了一种无需借助通讯的低电压加速反时限过电流保护(UAITOC)方案．该方案保证了线路出口处故障时保护能快速动作，并且适用于微电网并网和孤岛2种运行状态，无需切换保护定值就可以满足选择性和速动性的要求．同时该方案通过Digsilent软件仿真验证了所提保护原理的正确性．
Abstract: Traditional inverse-time overcurrent protection(ITOC)may not satisfy the requirement of selectivity and speed because of distributed generators’(DG)connection to grid and special variable operation modes in some condi-tions. The operation characteristics of DGs and micro-grid were considered here and a new protection scheme of in-verse-time overcurrent protection based on low voltage acceleration(UAITOC)was proposed. The new protection scheme，which does not need the use of communications can satisfy selectivity and improve action speed in all condi-tions without changing the settings of protections. It makes protective relays act instantaneously when fault occurs at line exit end. Simulation by Digsilent shows the protection principle is correct and feasible.
