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Three-phase reclosers with single-phase tripping are being more widely employed on utility distribution feeders. They have the advantages of increasing reliability for the customers on the feeders, because the majority of distribution feeder faults are single-phase. However, certain difficulties may occur when three-phase industrial and commercial loads, with three-phase transformers and motor loads are interrupted on one phase only. These include overheating of motors, ferroresonance of transformers, tripping of power electronic drives and backfeeding of distribution lines. This paper examines these effects, their severity and mitigation techniques.

Basic recommendations are provided for enhancing the reliability of new and existing capacitor controller installations by optimizing their resistance to surges. The sources and types of surges commonly experienced by capacitor controllers are discussed with consideration given to circuit parameters that can influence the magnitude of surges reaching the controller. Different controller surge protection configurations are examined including providing auxiliary secondary-side surge protection. The discussion culminates with some basic surge protection recommendations to enhance the lightning performance of capacitor controllers

This paper considers several approaches to use overcurrent protection to improve distribution reliability. Having more protective devices that are properly coordinated assures that the fewest customers possible are interrupted and makes fault-finding easier. Fusing is an inexpensive way to isolate faults, and this paper describes some often-overlooked fusing considerations. Applications of fuse blowing and fuse saving are also considered. Reclosing practices can be optimized to limit impacts on customers. In addition, single-phase protective devices can also limit customer outage time by reducing the number of customers affected

Historically, electrical distribution systems have been designed to deliver power from the distribution substations to the end users. The future evolution of the distribution system, as envisioned in EPRI's Advanced Distribution Automation (ADA) initiative, will merge power delivery with distributed intelligent control and communications systems. This paper covers the results of a survey of electric utilities and a follow-up seminar with survey participants. Survey responses were obtained from eleven US and Canadian utilities across a wide spectrum. Responders included large multi-state utilities, companies in large urban areas, publicly and privately owned utilities, and a small rural utility. These results will help to shape future planning as to the most effective pathways to move forward in the evolution of the distribution system of the future

Rpad is an open-source, interactive, Web-based analysis program. Rpad is an analysis package, a Web-page designer, and a GUI designer all wrapped in one. This paper covers the architecture of Rpad and how it draws on a number of open-source technologies. Demonstrations show how such technology has been used for data mining of outage databases. Open-source software is very good for piecing together technologies.

A description is given of a method of switched-capacitor control for damping of low-frequency power system oscillations. A form of self-tuning generalized predictive control with discrete constraints placed on the control signal is used. The control is calculated on the basis only of local network information. Simulation results are shown for a nonlinear model for a nine-bus power system. >

Momentary interruptions caused by lightning were a severe problem for a Champion International paper mill in upstate New York. Following a detailed investigation, the Niagara Mohawk Power Corporation (NMPC) installed line surge arresters to the supply circuit to eliminate lightning-caused interruptions. The paper mill is supplied by a 115-kV circuit which was characterized by low insulation level and poor grounding. Lightning arresters were found to be the best solution. Extensive line performance monitoring of the circuit performed before and after the arresters were installed has provided some valuable information. The arresters have successfully eliminated the lightning-caused interruptions.