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Abstract
This research aims at the protection coordination analysis of Datan Power Plant. Datan is a newly built power plant; the total power output is approximately 30% of the demand of northern Taiwan. Thus, an in-plant outage could affect the power system of Taiwan, and, if the protection system is not well coordinated, the whole plant could even outage and result in blackout of Taipower system. It is hence necessitated to evaluate the protection coordination of the Datan power system. The main content of this research includes the model building and the parameter collection for the protection analysis, the fault current calculation and the protection coordination analysis, under all possible operating modes of Datan’s generators.
In the protection analysis, the maximum and the minimum fault current for both the phase and the phase-to–ground faults should be evaluated. The maximum fault current refers to the Datan’s operating mode having all (total 12) generating units under operation and the plant’s 345kV switchyard of operating at the maximum short-circuit capacity of Taipower system in year 2009; as to the minimum fault current, it is assumed Datan’s all generators are out of service and the switchyard is operating at the minimum short-circuit capacity of Taipower in 2009.
The fault locations evaluated in this study include the output terminal of each generating unit, the 345kV underground cable connecting the main transformer and the switchyard, both sides of the auxiliary transformer, and the 4.16kV bus, （not including generator itself and the 480V system）, so that for each fault location, the maximum and the minimum fault current of both the phase fault and the ground fault are evaluated. Based on the protection coordination analysis results, suggestions are made ranging from the revised relay setting to the fault current calculation procedure.
Keywords: power system, fault current calculation, protection coordination
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