Topic
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.
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TL;DR: A back-up protection scheme for a transmission network that uses an action factor-based expert decision system to provide optimal fault clearance for faults located anywhere on the protected network is described in the paper.
Abstract: A back-up protection scheme for a transmission network is described in the paper. The back-up protection uses an action factor-based expert decision system (referred to as the BPES) to provide optimal fault clearance for faults located anywhere on the protected network. To achieve an optimal response, the BPES needs to know the topology of the network and the operating response of existing protection relays. Based on this information, the expert decision system will try to identify the feeder that contains the fault and which circuit breakers need to be tripped to clear the fault.
93 citations
15 Feb 1998
TL;DR: In this paper, the authors present the technical aspects of designing a dynamic voltage restorer to meet the stringent requirements of voltage dips mitigation with respect to the magnitude of voltage dip, fault duration, permissible line voltage deviations and response time.
Abstract: This paper presents the technical aspects of designing a dynamic voltage restorer to meet the stringent requirements of voltage dips mitigation with respect to the magnitude of voltage dip, fault duration, permissible line voltage deviations and response time. An introduction to IGCT technology based on latest transparent anode GTO (T-GTO) and gate technology is given. The performance of the DVR based on digital simulations is discussed. A description of a hardware-based real-time simulator model for the performance assessment of DVR in voltage dips mitigation is presented. The results of the real-time simulator are compared with the digital simulations. Finally, control and protection concepts for the DVR are highlighted.
93 citations
TL;DR: In this paper, the issue of appropriate test conditions with regard to reactive power injection to the grid is discussed and the stabilizing impact of rotating machines and resonant circuits is evaluated in detail.
Abstract: A major safety issue in grid-connected photovoltaics is to avoid nonintentional operation in islanding mode when the grid is being tripped. Worst-case conditions under which islanding can occur are specified analytically. The circuit that is commonly used for testing is described. The issue of appropriate test conditions with regard to reactive-power injection to the grid is discussed and the stabilizing impact of rotating machines and resonant circuits is evaluated in detail. Islanding test results for small inverters are presented. They confirm that very simple islanding protection methods that are commonly used, are likely to fail, if inverters are loaded with considerable capacitance. The obtained results support the assessment of the islanding protection function. They emphasize important points when defining new certification procedures for upcoming guidelines and standards.
92 citations
TL;DR: In this paper, the effects of the many sources of harmonics which occur on distribution systems are discussed and contrasted with the single source from a high-impedance ground fault.
Abstract: The effects of the many sources of harmonics which occur on distribution systems are discussed and contrasted with the single source of harmonics from a high-impedance ground fault. Field data are presented which show the complexity of modeling the ambient harmonics and the simplicity of the change in the phasor value of the third harmonic which occurs due to a high-impedance ground fault. This phasor change is shown to be unique and predictable and hence suitable for use in detecting these faults. It is shown that variations in ambient harmonics may be greater than the change due to a high-impedance ground fault and must be considered in the fault detection system. Calculations of fault current harmonics are simpler than those for the ambient harmonics. >
92 citations
TL;DR: Adaptive relaying proposes to provide protection functions that will adapt to changing power system conditions as discussed by the authors, where the adaptive out-of-step relay recognizes power system changes and uses a modified system impedance matrix to change relay settings An investigation of a Florida-Georgia 500 kV interconnection initially, used a simple two-machine mode to represent the interconnection After this approach is tested a three-machine Florida model will be constructed
Abstract: Adaptive relaying proposes to provide protection functions that will adapt to changing power system conditions The adaptive out-of-step relay presented recognizes power system changes and uses a modified system impedance matrix to change relay settings An investigation of a Florida-Georgia 500 kV interconnection initially, used a simple two-machine mode to represent the interconnection After this approach is tested a three-machine Florida model will be constructed The results from the two approaches will then be compared The configuration used to implement the relay consists of two or more phasor measurement units (PMUs), which provide synchronized real-time information regarding the state of the system These PMUs are discussed and data provided by the PMUs is analyzed >
92 citations