Title: Application of Inverse-Time Overcurrent Protection Based on Low Voltage Acceleration in Micro-Grid
作者: 李永麗; 金 強; 李博通; 李中洲 天津大學智能電網教育部重點實驗室，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
關鍵詞: ; 分布式電源; 微電網; 低電壓加速反時限過電流保護; 運行模式
Keywords: ; distributed generator; micro-grid; inverse-time overcurrent protection based on low voltage accel-eration; operation mode
分類號: TM773
文獻標識碼: A
摘要: 低壓配網中用的反時限過電流保護(ITOC)由于分布式電源(DG)的接入及微電網運行方式變化的特殊性從而不能滿足選擇性和速動性的要求．為此，基于分布式電源和微電網的運行及故障特征，提出了一種無需借助通訊的低電壓加速反時限過電流保護(UAITOC)方案．該方案保證了線路出口處故障時保護能快速動作，并且適用于微電網并網和孤島2種運行狀態，無需切換保護定值就可以滿足選擇性和速動性的要求．同時該方案通過Digsilent軟件仿真驗證了所提保護原理的正確性．
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.
