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Substation Automation and Relay Communications
Published in Walter A. Elmore, Pilot Protective Relaying, 2018
A protective relay is a device that monitors the power system for abnormal conditions and takes preventative actions to limit power system stress and to reduce equipment damage. With the early 8-bit microprocessor-based relay systems, protection of the power system was the primary function, but advances in the computing power of a microprocessor permitted additional functionality, such as metering, breaker reclosing, and communications. The communication’s interface in the typical microprocessor-based protective relay used EIA-RS232 serial communication port(s) connected to a VT100 terminal, or to a computer with a terminal emulation program. The protocol used was standard 8-bit ASCII; for which every number, letter or punctuation mark is represented by a set of 8 bits (1 byte). The EIA-RS232 interface provides a communications path between a single “master” and a single “slave.”
Protective Relaying for Power Distribution Systems
Published in Albert Thumann, Harry Franz, Efficient Electrical Systems Design Handbook, 2020
Protective relays are another way of achieving selective coordination and are required to operate power breakers above 600 volts. By definition, a protective relay is a device which when energized by suitable currents, voltages, or both, responds to the magnitude and relationships of these signals to indicate or isolate an abnormally operating condition. These relays have adjustable settings and can be used to actuate the opening of circuit breakers under various fault conditions.
Thermal Generating Plants
Published in Leonard L. Grigsby, and Distribution: The Electric Power Engineering Handbook, 2018
Relay coordination studies should be performed to ensure proper coordination of the relay protection system. The protective relay system may include overcurrent relays, bus differential relays, transformer differential relays, voltage relays, and various special function relays.
Optimum relay coordination for reliability evaluation of distribution system with allocation of wind turbine generators
Published in International Journal of Modelling and Simulation, 2023
Sandeep Gupta, Vidya Kant Dwivedi, Padmanabh Thakur, R.C. Bansal
The fast detection and quick disconnection of unhealthy parts of power systems play a vital role in minimising system disruption and, consequently, the cost of downtime associated with it. The protective relay needs to be in a position to distinguish between normal, abnormal, and failing conditions [1–4]. Relay coordination encompasses the concepts of discriminating, choosiness, and backup safety [5,6]. Presently, the consumption of electrical energy is increasing drastically, especially in economically developed nations. Thus, networks for electricity companies grow to be very complicated. To determine the minimal threshold discriminating margin among a relay and all of its backup relays in a complex electrical network, numerous repetitions of load flow analysis, fault calculations, and delineating primary and backup pairs are necessary. Only computer programming makes this feasible [7–9]. As a result, the ETAP programme performs numerical calculations at a rapid pace, automatically applies industry-accepted standards, and produces output reports that are simple to interpret.
Highly Available Nuclear Power in a Microgrid Configuration for the ORNL Distribution System
Published in Nuclear Technology, 2022
Microgrid island mode operation relies on protective relay in the BVS, SNS, and ORNL 161-kV switchyards to separate the microgrid from the bulk transmission system following a grid disturbance. The protective relay scheme has not been developed, and the base case (option 1 and option 2) assumes that the protective relay scheme is perfectly reliable. However, failures of the protective relay scheme remove the potential for power to be supplied from a 12-NPM plant to ORNL during a TVA bulk transmission system failure; therefore, failures of the protective relay scheme may be important to the availability estimate. Sensitivity 3 assumes a failure probability of 0.1 per demand of the microgrid separation protective relay scheme to understand the importance of this failure mode on the availability of power to ORNL.
Transmission Line Protection Using High-Speed Decision Tree and Artificial Neural Network: A Hardware Co-simulation Approach
Published in Electric Power Components and Systems, 2022
Amr Ahmed Fayyad, Amal Farouk Abdel-Gawad, Ahmed Mahmoud Alenany, Saber Mohamed Saleh
Recently, developments have taken place in several protection schemes based on artificial intelligence, such as ANN (artificial neural network) and their wavelet hybridization. ANN related work in [15]. A real-time implementation of a protective relay is accomplished in [16] using fuzzy logic. In [17, 18] a systematic strategy for detecting and classifying faults using wavelet transform in conjunction with ANN was proposed. These techniques are mainly developed to detect and classify the fault, hence do not provide any information regarding fault location, and the approaches that combine wavelet and fuzzy suffers from the more the number of fault areas the more the associated rules for the fuzzy model and the optimization becomes a stressful task. In [19], the authors use wavelet current signals analysis with mother wavelet db6 to feed the wavelet entropy values of wavelet coefficients at levels 3 into a radial basis function neural network for fault detection, classification, and localization. This technique is non-directional i.e. they are unable to distinguish between internal and external faults or their zone.