No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The status quo and thinking of relay protection
Abstract
Based on researching IEC61850, analysis of the feature for description of digital substation, and linking the development situation of relaying, this paper discusses the future development of the bay level equipment in digital substation and analyzes the hardware, software, net and application belong to the bay level. It proposes design thoughts of relay protection: modularization of hardware, componentization of software, networking of relay function, integrating of equipment function, and expounds the relevant aspects.
Protection system is the first defense line to ensure the safe operation of power grid, so it is of great significance to study its reliability. Currently, the reliability research of protection system mainly focuses on misoperation and fail-to-operation, yet it does not effectively take advantage of defect information which would occur in great probability. This paper analyzes defect information of protection devices and estimates the parameters of two-parameter Weibull distribution as well as the reliability function, failure rate function and so on. The study case shows that it can supply reference for further reliability assessment of protection systems by calculating the parameters of Weibull distribution and analyzing indices such as reliability, failure rate, and mean time between failures.
A method of analyzing power system transient signals based on the genetic algorithm and neural network was proposed to improve the analysis precision of the transient signals. A period component varied in spectral waveform, and a non-period component varied in exponential waveform and switching operation sequence. The signal parameters, which were assumably estimated based on numeric differential coefficient and genetic algorithm, were used as the beginning parameters of neural network. The fundamental frequency was treated as an undetermined value, and was adjusted to estimate the signal frequency and all harmonics, amplitudes and phases. The Matlab simulation results demonstrate that the algorithm achieves high accuracy and rapid convergence.
Some protection problems exist in Vessel Integrated Power System (VIPS), for example, a lot of conditions of VIPs make it difficult to confirm setting values; protection time-delay becomes greatly longer based on time principle as system rating increases, cable is short leading to distinguish two-step fault hard. The paper brings forward an intelligent protection method in which current and voltage rms are taken as input while discriminating result of NN as output based on Back Propagation Neural Networks (BPNN). The method uses BPNN discriminating result to control breakers switching on and off in VIPS, thus to realize fault location of VIPS intelligently. The paper introduces interface principle between PSCAD/EMTDC and C and illuminates the choosing and processing of input quantity of neural network. Simulation verification is made base on BPNN C procedure and the result demonstrates the intelligent protection method is effective in protecting VIPS and enhancing vessel's fighting capacity and vitality.
Zeolite-based catalyst materials are widely used in chemical industry. In this chapter, the applications of zeolites and zeotypes in the catalytic conversion of oil and gas are reviewed. After a general introduction to zeolite science and technology, we discuss refinery applications, such as fluid catalytic cracking and hydrocracking, and also a wide variety of important petrochemical processes, such as alkylation and isomerization. The fields of low-temperature zeolite-assisted methane activation and methanol-to-hydrocarbon conversion are also covered, as well as several zeolite-catalyzed organic reactions with the aim to synthesize fine chemicals and pharmaceutical intermediates. By reviewing the processes, a wide range of catalytic functionalities are discussed, including Brønsted and Lewis acid sites, basic sites as well as metal and redox sites. The chapter continues with a discussion of the effects of zeolite-binder interactions in commercial catalysts, where the zeolite is only part of the system. We show how modern microspectroscopy methods provide detailed insight into the complex structure of these catalyst materials. Finally, we present future directions, which may include new zeolite-based processes for chemicals production or energy conversion, while new synthetic and characterization tools are envisioned to contribute to the accelerated discovery of new zeolite framework structures.
To comprehensively understand the configuration of protective relaying and its operation conditions of SGCC in 220kV and above voltage AC systems in 2013, related data information is obtained from the statistical analysis and operation management module, which covers all levels of dispatching institutions, and according to definitions and requirements given by Evaluation Rules of Protection Equipment and Power System Stability Control Devices, the overall analysis on the scale and the configuration of protective relaying as well as its operation conditions in 2013 are carried out. Besides that, two typical incorrect actions of protective equipment in 2013 are presented in detail. On this basis, effective suggestions for operation and maintenance of protective relaying, its professional management and other works such as data mining are put forward.
ResearchGate has not been able to resolve any references for this publication.