Fault Characteristic and Protective Coordination for the Low Voltage Microgrid Supply System

• Main Authors: Chia-Hsiang Chuang, 莊家祥
• Other Authors: 周至如
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/j2smgd

碩士 === 國立臺北科技大學 === 電機工程系研究所 === 99 === In this thesis, the fault characteristic of low voltage microgrid supply system are analyzed and the fault protective coordination is planned. Different system frameworks which include three-phase-three-wire(3Φ3W) and three-phase-four-wire (3Φ4W) with multiple-point system grounding and single-point system grounding under utility parallel operation and island operation are considered. First of all, modeling and fault simulations by the alternative transient program(ATP) of the electromagnetic transient program(EMTP) for the low voltage microgrid supply system are presented, in which the voltages and currents at various points under different fault types and different fault points are analyzed. The fault points include mainbus, feeders, load terminals and source terminals, while the fault types including phase-to-phase, phase-to-ground and phase-to-neutral faults are taken into account. Based on the fault characteristic analysis result, the system protective coordination is planned by advanced digital relays which mainly use the inverse-time overcurrent relays and directional overcurrent relays. Finally, from the result of fault characteristic analysis and protective coordination planning for an actual low voltage microgrid supply system, the encountered protective coordination problems and improved strategies are discussed for obtaining the suitable coordination and increasing the performance of system protection.