Search

Feeder incident information is quite useful for evaluating the quality of the electricity distribution system. The improving scheme can be taken based on this information as well. In this paper, an adequate way for gathering this information was developed and the related messages from SCADA historical event log were analyzed by a novel methodology. For correctly and rapidly analyzing the collected messages purpose, this paper developed a time-driven and event-driven approach in order to express the exact feeder incident affairs. The feeder fault information can be fetched precisely and efficiently according to the result of this paper. Furthermore, the outage duration of the fault feeder, excluding the load transferring condition, was computed as well. For the sake of cyber security purpose, this paper developed a low cost and secured file transfer mechanism for transferring the event log from the SCADA system to an intranet web server. Corresponding to the web-based application software based on the result of this paper was consequently developed and installed on the sever of information management department of Taiwan Power Company (Taipower) for all SCADA control centers, and the software is running successfully. [ABSTRACT FROM AUTHOR]

Currently, self-healing is one of the most important functions in the smart grid. Meanwhile, fault detection, isolation, and restoration of feeder automation systems dominate the self-healing function in power distribution systems. The steps of the aforementioned function depend on the fault flag status of the feeder terminal unit. The conditions for setting this flag are judged by the feeder terminal unit overcurrent detecting curve. This paper found an efficient approach to calculate this curve via a half-interval method. Versatile application software with the curve plotting capability was also developed and deployed on the web server of the information-management department of Taiwan Power Company and is running successfully. [ABSTRACT FROM AUTHOR]

Abstract: This work presents a new approach to optimize overcurrent relay coordination in power distribution systems by using a genetic algorithm, involving transformer protection. An effective objective function with constraints is adopted to solve the relay coordination problem, considering not only the time setting but also the current setting multiplier. There are various types of curves such as Very Inverse (VI), moderate or Normal Inverse (NI) of relays and the damage curve of the transformer are considered in the simulation, the result shows that the proposed method is fast, accurate and applicable. In this study, time–current relay curves are plotted on a log–log scale plan and compared with those of an existing industrial power system, in addition, an example of single-ring power distribution system is tested to demonstrate the coordination and confirm that the proposed approach method is practical. [Copyright &y& Elsevier]

Conventional optimization methods for approaching overcurrent relay settings focus on minimizing the operating time of total relays at maximum fault current to accelerate the fault clearance time. However, to judge whether the entire relay curve of each relay pair always meets the constraints of 0.2 or 0.3 sec to the object curve is rather difficult as the curves may have different slopes. Additionally, the coordination time at the closest position for the curves of a relay pair should be checked for coordination validation. Therefore, this work presents a novel partial differentiation approach method to ensure that the curves of overcurrent relay coordination do not intersect with each other and violate the coordination time interval. Relay setting values are normally plotted on the time-current plane to verify the closing or intersection between relay pairs. Thus, a computer program based on the partial differentiation approach is also developed to calculate the current value of the intersection or closest position. Furthermore, a case study involving an industrial power system demonstrates the effectiveness of the proposed method by validating the results of optimization relay coordination. [ABSTRACT FROM AUTHOR]