Power-system protection

About: Power-system protection is a research topic. Over the lifetime, 6353 publications have been published within this topic receiving 117961 citations.

Sequential Tripping Strategy for a Transmission Network Back-Up Protection Expert System

Abstract: This paper describes a sequential tripping strategy used in a wide area back-up protection expert system (BPES) to combat situations in which protection relays have maloperated or information is missing. The BPES is an innovative back-up protection scheme designed to prevent the occurrence of widespread blackouts. The BPES evaluates the certainty that transmission lines are likely to be affected by the fault and uses a sequential tripping strategy to isolate the fault if a firm decision is not available due to maloperated relays and/or missing information. The mode of analysis and the sequential tripping strategy ensures that the BPES will clear a fault at minimum risk to the network. An example is included to demonstrate how the certainty factor based sequential tripping strategy is employed by the BPES to clear a fault which occurred on the South Western part of the UK National Grid System.

Automated intelligent configuration tool for power system protection and control and monitoring devices

Abstract: An automatic configuration tool for use with power protection and restoration devices such as reclosers and switches in power transmission and distribution systems. An automatic configuration application provides a plurality of menus to a user on a graphical user interface to enable the user to select a plurality of options that are processed by various calculation engines to determine the configuration settings for a specific power protection and restoration device. The configuration settings that are generated are downloaded directly into the power protection and restoration device to provide protection, control and monitoring.

A new method for fault detection during power swing in distance protection

Abstract: During a power swing, currents and voltages behave such as a fault. Therefore, Power swing blocking function in distance relays is necessary to discriminate between a power swing and a fault. Otherwise power swings can be considered as a fault and causes relay trip. The main problem happens when during power sings a fault occurs. In this case, distance relays should be unblocked. In this paper, a new method based on the DC component of fault currents will be proposed to detect a fault during power swing blocking. The proposed method can detect single-phase to ground, two-phase to ground and three-phase fault. Applying the new method on a sample network reveals the features of the method.

Improving the Grid Operation and Reliability Cost of Distribution Systems With Dispersed Generation

Abstract: In this work, a mathematical model to analyze the impact of the installation and operation of dispersed generation units in power distribution systems is proposed. The main focus is to determine the trade-off between the reliability and operational costs of distribution networks when the operation of isolated areas is allowed. In order to increase the system operator revenue, an optimal power flow makes use of the different energy prices offered by the dispersed generation connected to the grid. Simultaneously, the type and location of the protective devices initially installed on the protection system are reconfigured in order to minimize the interruption and expenditure of adjusting the protection system to conditions imposed by the operation of dispersed units. The interruption cost regards the unsupplied energy to customers in secure systems but affected by the normal tripping of protective devices. Therefore, the tripping of fuses, reclosers, and overcurrent relays aims to protect the system against both temporary and permanent fault types. Additionally, in order to reduce the average duration of the system interruption experienced by customers, the isolated operation of dispersed generation is allowed by installing directional overcurrent relays with synchronized reclose capabilities. A 135-bus real distribution system is used in order to show the advantages of using the mathematical model proposed.