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: In this paper, an innovative power line signaling based anti-islanding scheme was developed in response to the challenge, which broadcasts a signal from a substation to the DG sites using the distribution feeders as the signal paths.
Abstract: Anti-islanding protection of distributed generators (DG) is a significant technical barrier to the emerging DG industry. This paper presents an innovative power line signaling based anti-islanding scheme developed in response to the challenge. The scheme broadcasts a signal from a substation to the DG sites using the distribution feeders as the signal paths. A DG is considered as islanded from the upstream system if the signal cannot be detected at the DG site. The proposed scheme has been evaluated using analytical, simulation and field tests. The results are very promising. This paper presents the main ideas of the scheme and its design considerations. Methods to create and detect the signals are shown and their performances are analyzed.
269 citations
01 Apr 1996
TL;DR: A computer model for transient analysis of a network of buried and above ground conductors is presented in this paper, which is based on the electromagnetic field theory approach and the modified image theory.
Abstract: A computer model for transient analysis of a network of buried and above ground conductors is presented The model is based on the electromagnetic field theory approach and the modified image theory Validation of the model is achieved by comparison with field measurements The model is applied for computation of transient voltages to remote ground of large grounding grid conductors Also computation of longitudinal and leakage currents, transient impedance, electromagnetic fields, and transient induced voltages is possible This model is aimed to help in EMC and lightning protection studies that involve electrical and electronic systems connected to grounding systems
267 citations
TL;DR: In this article, a new approach is proposed to solve the directional overcurrent relay coordination problem, which arises from installing distributed generation (DG) in looped power delivery systems (PDS).
Abstract: A new approach is proposed to solve the directional overcurrent relay coordination problem, which arises from installing distributed generation (DG) in looped power delivery systems (PDS). This approach involves the implementation of a fault current limiter (FCL) to locally limit the DG fault current, and thus restore the original relay coordination. The proposed restoration approach is carried out without altering the original relay settings or disconnecting DGs from PDSs during fault. Therefore, it is applicable to both the current practice of disconnecting DGs from PDSs, and the emergent trend of keeping DGs in PDSs during fault. The process of selecting FCL impedance type (inductive or resistive) and its minimum value is illustrated. Three scenarios are discussed: no DG, the implementation of DG with FCL and without FCL. Various simulations are carried out for both single- and multi-DG existence, and different DG and fault locations. The obtained results are reported and discussed.
265 citations
01 Nov 2008
TL;DR: An ant colony system algorithm is used to derive the optimal recloser and DG placement scheme for radial distribution networks and a composite reliability index is used as the objective function in the optimization procedure.
Abstract: Optimal placement of protection devices and distributed generators (DGs) in radial feeders is important to ensure power system reliability. Distributed generation is being adopted in distribution networks with one of the objectives being enhancement of system reliability. In this paper, an ant colony system algorithm is used to derive the optimal recloser and DG placement scheme for radial distribution networks. A composite reliability index is used as the objective function in the optimization procedure. Simulations are carried out based on two practical distribution systems to validate the effectiveness of the proposed method. Furthermore, comparative studies in relation to genetic algorithm are also conducted.
254 citations
04 Jun 1996
TL;DR: In this paper, the authors presented a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method, which is more accurate than others, e.g., the measurement of angular velocity of the rotating voltage phasor.
Abstract: The main frequency is an important parameter of an electrical power system. The frequency can change over a small range due to generation-load mismatches. Some power system protection and control applications, e,g, frequency relay for load shedding, load-frequency controller, require accurate and fast estimation of the frequency. Most digital algorithms for measuring frequency have acceptable accuracy if voltage waveforms are not distorted. However, due to nonlinear devices, e,g, semiconductor rectifiers, electric arc furnaces, the voltage waveforms can include higher harmonics. The paper presents a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method. Simulation results confirm, that the proposed method is more accurate than others, e,g, than the method based on the measurement of angular velocity of the rotating voltage phasor.
254 citations