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Fault Management System (FMS) is one of the main functions in Distribution Automation System (DAS); however, the conventional FMS cannot be used in distribution systems with Distributed Generators (DGs) due to the lack of directional function. The directional fault detection device is expensive due to the expensive directional module used. In a wide-ranging distribution system, the investment cost will be very high if the fault detecting devices are expensive. Therefore, the design and implementation of a cost-effective FMS for distribution system with DGs is necessary. A Multi-Level Fault-Current Indicator (MLFCI) having a plurality of reed switches used to detect different current levels is proposed in this paper. The hardware prototype is designed and implemented. An algorithm used to locate fault based on the different fault current levels is derived. A MLFCI-based FMS for distribution systems with DGs is then realized. Experimental results demonstrate the feasibility of the proposed MLFCI. Simulation results are then used to demonstrate the validity of the proposed MLFCI-based FMS for distribution systems with DGs. [ABSTRACT FROM AUTHOR]

Fault indicating devices such as fault indicators (FIs) have been widely used in distribution systems to improve reliability and reduce outage duration. Recently, FIs with communication interfaces are integrated into distribution automation (DA) to further reduce fault-finding time by reporting FIs' statuses back to control center. When faults occur, a lot of alarms and fault information are received from Outage Management System (OMS), Trouble Call System (TCS) and Customer Information System (CIS) and are shown to system operators. As a result, the identification of faulted line sections in a wide-ranging distribution system from FIs' statuses is not an easy task, especially when multiple faults occur simultaneously and/or distributed generators (DGs) are connected. An automatic and fast faulted line-section location method for distribution systems based on FIs is proposed in this paper. The line sections between adjacent FIs can be treated as a possible fault location (PFL) and the fault current detected by the FI can be considered as line current (LC) flowing between the adjacent PFLs. A relationship matrix between PFLs and LCs is then derived and used to design the proposed automatic and fast faulted line-section location method. The faulted line sections can then be located effectively and efficiently by the proposed method. Test results for an actual distribution system demonstrate the validity of the proposed faulted line-section location method. [ABSTRACT FROM PUBLISHER]

Abstract: Distributed generator (DG) resources are small, self-contained electric generating plants that can provide power to homes, businesses or industrial facilities in distribution feeders. They can be used to reduce power loss and improve service reliability. However, the values of DGs are largely dependent on their types, sizes and locations as they were installed in distribution feeders. A value-based method is proposed in this paper to enhance the reliability and obtain the benefits for DG placement. The benefits of DG placement described in this paper include power cost saving, power loss reduction, and reliability enhancement. The costs of DG placement include the investment, maintenance and operating costs. The proposed value-based method tries to find the best tradeoff between the costs and benefits of DG placement and then find the optimal types of DG and their corresponding locations and sizes in distribution feeders. The derived formulations are solved by a genetic algorithm based method. Test results show that with proper types, sizes and installation site selection, DG placement can be used to improve system reliability, reduce customer interruption costs and save power cost; as well as enabling electric utilities to obtain the maximal economical benefits. [Copyright &y& Elsevier]