| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 96 === The thesis aims at the evaluation of protection coordination for the distribution system of island power system such as that of Kinmen and Matsu. The main research focuses on the evaluation of whether the criteria adopted for estimating the maximum and the minimum short circuit currents (Imax and Imin) of the main-land power system are still applicable to the island power system. The criteria under evaluation refer to the estimation of Imax by simulating the three-phase fault and the estimation of Imin by simulating the single-phase-to-ground fault, both ignoring the operation of generating units for the main-land power system. Apart from evaluation the Imax and Imin criteria, as Kinmen and Matsu had been designed with the neutrally ungrounded power system are presently being changed into the grounded system, thus there is necessity of evaluating the protection coordination, particularly at the interface locations, of both systems, which shall be also under evaluation in this research.
The research procedure includes: the model formulation, the data collection and the modes estimation of Imax and Imin by accounting for the operation of generating units, as well as the review of protection coordination for both Kinmen and Matsu distribution systems. Under the peak and off-peak generation modes, the author estimates Imax and Imin for the selected feeder locations, The simulation shows that the short-circuit current characteristics of the island power system such as Kinmen and Matsu, differ from that of the main-land. Under most occasions, the single-phase-to-ground fault current is higher than that of three-phase and thus the Imax and Imin evaluation criteria adopted for the main-land is not applicable to the island such as Kinmen and Matsu. As to the phase relays, the coordination is necessitated between the grounded and the ungrounded power systems, but the coordination is not necessitated to the ground relays.
|
|---|
