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 novel approach to the estimation of the harmonic sources by means of a Bayesian approach is proposed and the procedure also allows the ldquoqualityrdquo of the obtained estimates to be assessed.
Abstract: Throughout the last years, with the liberalization of the energy market, the localization of the sources of power quality disturbances has become a nodal point for operators and customers. In the liberalized market, knowledge of the system status, along with the uncertainty affecting the estimated data, is required to operate management and control issues such as energy dispatching and protection coordination. In distribution systems, too many measurement instruments would be needed to obtain a complete observation of the electric quantities. Thus, model-based state-estimation techniques can be implemented to exploit the few real-time measurements from the field and all the other available information to estimate the desired quantities. In this paper, a novel approach to the estimation of the harmonic sources by means of a Bayesian approach is proposed. The procedure also allows the ldquoqualityrdquo of the obtained estimates to be assessed. The theoretical fundamentals of the method are discussed, and results relevant to a simple distribution network are presented.
59 citations
01 Oct 2006
TL;DR: This paper investigates and selects two appropriate measures of the importance of Birnbaum's measure used to identify the weak points of the all-digital protection system that needs to be improved if one is to improve overall system reliability.
Abstract: Analysis of the importance of various components of the all-digital protection system is a key part of the system reliability quantification process. The importance analysis for all-digital protection systems was not covered in the literature so far. This paper investigates and selects two appropriate measures of the importance. The first is the Birnbaum's measure used to identify the weak points of the all-digital protection system that needs to be improved if one is to improve overall system reliability. The second measure uses criticality importance to prioritize maintenance actions. To demonstrate the application of the proposed measures, this paper first introduces alternative architectures of all-digital protection systems. The associated reliability block diagrams as well as the exact system reliability are then given. Afterwards, the component importance for the alternative architectures is analyzed and discussed
59 citations
TL;DR: The authors establish the relevance of PetriNet modeling to protection studies and illustrate how the different Petri net models capture the information that is of importance to both qualitative and quantitative evaluation of protection schemes.
Abstract: The authors establish the relevance of Petri net modeling to protection studies. They illustrate how the different Petri net models capture the information that is of importance to both qualitative and quantitative evaluation of protection schemes. The marked Petri nets allow one to evaluate the qualitative performance measures of conservativeness, safeness, and properness. Time Petri nets are able to represent the timing parameters of protection schemes, and serve as a tool for the establishment of relationships between these parameters, in order that the coordination between primary and backup protection is ensured. An alternative means of representing timing information is the timed Petri net, which is useful in the computation of the cycle times of the operational cycles of protection schemes. Stochastic Petri nets adequately represent the stochastic nature of protection. Their advantage over simulation techniques as a means of computing the mean sojourn time and the steady-state probability of occupancy of each state of the protection scheme is demonstrated. >
59 citations
29 Nov 2001
TL;DR: In this article, a system for exploitation of the energy provided from photovoltaic panels is presented, in which the energy is converted, adapted and injected into the electric utility grid.
Abstract: In this work the study of a system for exploitation of the energy provided from photovoltaic panels is presented. Through this system the energy is converted, adapted and injected into the electric utility grid. In this way an amount of electrical energy consumed by one given customer is produced, having the advantage that it can be installed easily in the proper place of consumption, dispensing with the use of a transmission system. The current has sinusoidal shape in the system output, taking as reference the electric grid, obtaining low total harmonic distortion, thus the quality of the electric energy is preserved. Moreover, other requirements are achieved, as the galvanic isolation between the panels and the utility grid, and the protection against energy failure. The power stages, the control strategy, the system's operation principle, the simulation and experimental results acquired with the prototype constructed in the laboratory are presented.
59 citations
TL;DR: In this paper, simple recursive expressions for the harmonics using a sampling rate of 12 times a cycle were given for a three-phase, three-winding power transformer, which were used as the basis for a one cycle algorithm which was compatible with proposed digital line protection schemes.
Abstract: This paper presents an algorithm for digital protection of a three-phase, three-winding power transformer. Simple recursive expressions are given for the harmonics using a sampling rate of 12 times a cycle. These expressions are used as the basis for a one cycle algorithm which is compatible with proposed digital line protection schemes. The algorithm was tested on data obtained from a model transformer. Test results are given for 19 cases of energizations and faults.
59 citations