Detailed modelling and analysis of digital mho distance relay with single-pole operation

This paper introduces a methodology for modelling a digital admittance-type distance relay using PSCAD/EMTDC. The proposed distance relay was tested in a simulation of the Brazilian power grid with predetermined fault scenarios. The goal of this paper is to make a detailed evaluation of the mho distance relay. The main aspects include the correct operation of the distance relay, fault resistance effects on the mho characteristics, and the fault detection time of this relay. A new approach to analyse the fault detection time is presented, considering several simulated fault scenarios. The results demonstrate that the fault resistance influences the fault detection time and severely affects the distance relay’s general performance. The fault detection time is not constant. It varies within a time interval, considering different fault types, fault locations, and fault resistances. The confidence interval calculation provides a detailed range of the fault detection time, considering its upper and lower limits

Dynamic quadrilateral characteristic based distance relays for transmission lines equipped with TCSC

Copyright: © 2021 by the authors. A two-fold adaptive dynamic quadrilateral relay is developed in this research for protecting Thyristor-Controlled Series Compensator (TCSC)-compensated transmission lines (TLs). By investigating a new tilt angle and modifying the Takagi method to recognize the fault zone identifier, the proposed relay adapts its reactive reach and resistive reach separately and independently. The investigated tilt angle and identified fault zone use the TCSC reactance to compensate its effect on the TL parameters and system homogeneity. Excessive tests are simulated by MATLAB on the non-homogenous network, IEEE-9 bus system and further tests are carried out on IEEE-39 bus system in order to generalize and validate the efficiency of the proposed approach. The designed trip boundaries are able to detect wide range of resistive faults under all TCSC modes of operations. The proposed approach is easy to implement as there no need for data synchronization or a high level of computation and filtration. Moreover, the proposed adaptive dynamic relay can be applied for non-homogeneity systems and short as well as long TLs which are either TCSC-compensated or -uncompensated TLs

A New Relaying Method for Third Zone Distance Relay Blocking During Power Swings

Due to the increasing complexity of modern bulk power systems, the power swing identification, blocking, and protection have become more challenging than they used to be. Among various transmission line protection methods, distance relays are the most commonly used type. One of the advantages of using distance relays is the zoned protection which provides redundancy. However, the additional redundancy comes with a problem that it increases the probability of incorrect operation. For example, the undesired operation of the third zone distance protection during power swing scenarios has been attributed as one of the major causes for creating large-scale blackouts. Some research works in the literature investigate proper identification of stable and unstable power swing conditions. Most research works dwell on identification of power swing conditions but do not address how the scheme could be used for blocking the third zone of distance relays during stable power swings. Also, the current power swing detection schemes are often very complex to implement for a relaying engineer or are not fast enough for blocking the third zone distance element. This research proposes a reliable and fast methodology for the third zone blocking (TZB) during power swings. The new mathematical formulations and derivations are based on sound time tested power system theory and are simpler to understand for a relaying engineer to implement this technique. The algorithm proposed in the research can prevent unnecessary tripping of distance relays during power swings. The algorithm also overcomes the shortcomings of the conventional power swing identification methods when applied for the third zone blocking. A first zero-crossing (FZC) concept is introduced as the criteria for identifying stable power swing or out-of-step phenomena. The analysis is based on system stability point of view and utilizes power-angle equations. The proposed algorithm could be applied at every discrete time interval or time step of a distance relay to detect power swing points. It could also be applied to any transmission line in the power system by finding an equivalent single machine infinite bus (SMIB) configuration individually for each line on a real-time basis, which is one of the primary advantages of the proposed method. In the thesis work, the proposed technique is first demonstrated using a simple single machine infinite bus system. The TZB algorithm is then tested using a modified Western Electricity Coordinating Council (WSCC) power system configuration using Power System Analysis Toolbox (PSAT) simulations. The code is written in MATLAB. The TZB method is then further analyzed using electromagnetic simulations with Real-Time Digital Simulator (RTDS) on WSCC system. The proposed method uses small time step simulations (50 μs) to take various aspects of power system complexity into consideration, such as different harmonics presents in the system, synchronous machine operation at different speeds, travelling wave representation of transmission lines instead of purely lumped parameter representation, etc. The investigations as mentioned above and the results show that the proposed TZB scheme is a straightforward and reliable technique, involving only a few calculation steps, and could be applied to any power system configuration. The main novelty of this technique is that it does not require a priori stability study to find the relay settings unlike conventional power swing identification or distance relay blocking techniques. The inputs to the relay are basic electrical quantities which could be easily measured locally on any transmission line. The local measurements would make the implementation of the proposed TZB simpler for relaying applications compared to Wide Area Measurement System (WAMS) based techniques. In a WAMS based relaying technique - the cost associated with the communication network, reliability of the communication network, impact of communication delay on relay, etc all become factors for actual industry use

Protection challenges in future converter-dominated power systems : investigation and quantification using a novel flexible modelling and hardware testing platform

Error on title page – year of award is 2023.The research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor). The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection. It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system. Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers. An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems.The research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor). The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection. It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system. Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers. An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems

The 1982 NASA/ASEE Summer Faculty Fellowship Program

A NASA/ASEE Summer Faculty Fellowship Research Program was conducted to further the professional knowledge of qualified engineering and science faculty members, to stimulate an exchange of ideas between participants and NASA, to enrich and refresh the research and teaching activities of participants' institutions, and to contribute to the research objectives of the NASA Centers

Databook for human factors engineers. Volume 2 - Common formulas, metrics, definitions

Human factors engineering manual including mathematical formulas, nomographs, conversion tables, units of measurement, and nomenclature

Matlab

This book is a collection of 19 excellent works presenting different applications of several MATLAB tools that can be used for educational, scientific and engineering purposes. Chapters include tips and tricks for programming and developing Graphical User Interfaces (GUIs), power system analysis, control systems design, system modelling and simulations, parallel processing, optimization, signal and image processing, finite different solutions, geosciences and portfolio insurance. Thus, readers from a range of professional fields will benefit from its content

13th Annual Review of Progress in Applied Computational Electromagnetics at the Naval Postgraduate School, Monterey, CA, March 17-21, 1997, Conference Proceedings Volumes I & II

Includes Volumes 1 &

Proceedings of the First International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics

1st International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Kruger Park, 8-10 April 2002.This lecture is a principle-based review of a growing body of fundamental work stimulated by multiple opportunities to optimize geometric form (shape, structure, configuration, rhythm, topology, architecture, geography) in systems for heat and fluid flow. Currents flow against resistances, and by generating entropy (irreversibility) they force the system global performance to levels lower than the theoretical limit. The system design is destined to remain imperfect because of constraints (finite sizes, costs, times). Improvements can be achieved by properly balancing the resistances, i.e., by spreading the imperfections through the system. Optimal spreading means to endow the system with geometric form. The system construction springs out of the constrained maximization of global performance. This 'constructal' design principle is reviewed by highlighting applications from heat transfer engineering. Several examples illustrate the optimized internal structure of convection cooled packages of electronics. The origin of optimal geometric features lies in the global effort to use every volume element to the maximum, i.e., to pack the element not only with the most heat generating components, but also with the most flow, in such a way that every fluid packet is effectively engaged in cooling. In flows that connect a point to a volume or an area, the resulting structure is a tree with high conductivity branches and low-conductivity interstices.tm201