Relay Settings Research Articles

Optimal Relay Coordination for DG-Based Power System Using Standard and User-Defined Relay Characteristics

The operating time of directional overcurrent relays (DOCRs) can be reduced with user-defined relay characteristics considering plug setting (PS), time multiplier setting (TMS), and relay characteristic coefficients (λ and γ). This study presents a comparative analysis of relay coordination with standard and user-defined relay characteristics. The proposed relay coordination scheme is formulated as a non-linear constraint optimization problem. The grey wolf optimization (GWO) algorithm is used to determine the optimal relay settings and total operating time of DOCRs. The performance of the proposed scheme is tested on the standard 8-bus, 9-bus, and 15-bus systems. The results show that the total operating time of DOCRs with user-defined relay characteristics is better than that with standard relay characteristics. The results of the GWO algorithm are compared with the performance of optimization techniques used in literature to solve the relay coordination problem.

Comparative Study of Relay Coordination in a Microgrid with the Determination of Common Optimal Settings Based on Different Objective Functions

This study aims to analyze the optimal settings of directional overcurrent relays (DOCRs) for the protection of an alternating current (AC) microgrid in both islanded and grid-connected operation modes. In this context, two different types of objective functions are used for comparing the total operating time of all primary DOCRs. The optimal settings obtained in either mode of the microgrid are different due to the variable magnitude of fault currents. The proposed protection coordination scheme is formulated as a mixed-integer non-linear programming problem, and the settings are obtained using various optimization techniques such as firefly algorithm, simulated annealing algorithm, and genetic algorithm. The results show that the settings obtained in common operation modes are robust as no miscoordination of relays occurs in any of the operation modes.

Koordinasi Adaptif DOCR Pada Sistem Transmisi Loop Multi Generator Menggunakan Modified Firefly Algorithm-Artificial Neural Network

Protection system is a very important component in the electric power distribution system. With good reliability, the distribution of electrical power will be better, one of which is by minimizing disruption to the system quickly, precisely and accurately. Components used in protection systems are directional overcurrent relays (DOCR). In this study proposed optimal and adaptive protection coordination using the Modified Firefly Algorithm-Artificial Neural Network (MFA-ANN) tested on the IEEE 9 real bus loop system with 4 generation combinations. Optimization using MFA will get the Time Delay Setting (TDS) and Ipickup (lowset) values. The ANN used is Backpropagation Lavenberg Marquardt (BPLM) After the BPLM learning process, we will get the weight and bias values of the training results and later as a reference value to get the value of TDS and Ipickup relay. The process will produce relay settings automatically based on the results of optimization and MFA-ANN training which are then simulated on the IEEE 9 bus loop system. The results achieved by MFA-ANN are suitable methods for modeling optimal and adaptive relay coordination systems. ANN training with the BPLM algorithm produces the smallest MSE value of 5.9308xE-10.

REVOLUTIONARY SPECTATORSHIP AND SUBALTERNITY: FOUCAULT IN IRAN

ABSTRACTIn this article, I offer a novel reading of Michel Foucault's Iranian writings and probe their unexplored linkages with longstanding historiographical debates. I argue that these writings run headlong into the conceptual aporias of political modernity by contesting the assumed parallelism between consciousness and history and between subjects of history and history as Subject. I take up this problem through the double frame of revolutionary spectatorship and subalternity. In the first instance, I analyze Kant's contradictory reflections on the French Revolution and Marx and Engel's response to the (failed) revolutions of 1848 to show how uprisings are made to conform to a theory of the subject. In the second instance, in conversation with subaltern studies (Guha, Chakrabarty, and Spivak), I focus on the problem of representing the revolutionary subject or insurgent consciousness. Foucault's Iranian writings problematize the particular way the revolutionary subject (the person who rises up [se lève], in Foucault's vocabulary) is represented, or historiographically phrased. I argue that the confounding factor in this phrasing, the hard object that resists integration, is religion. I build a set of relays between genres of writing—philosophical journalism, philosophy of history, and subaltern historiography—that are subtended by this problem of incommensurability in order to illustrate the double bind of phrasing a religious subject in revolt. Across these heterogeneous conceptual grammars of historical analysis, I track “religion” and the “colonial” as différends in relation to what counts as a subject of history or history as Subject, and I show how religious and colonial phrasings (of history and subjectivity) find themselves in a position that has lost the capacity to claim a position.

Coordination of dual setting overcurrent relays in microgrid with optimally determined relay characteristics for dual operating modes

Fault current magnitude in a microgrid depends upon its mode of operation, namely, grid-connected mode or islanded mode. Depending on the type of fault in a given mode, separate protection schemes are generally employed. With the change in microgrid operating mode, the protection scheme needs to be modified which is uneconomical and time inefficient. In this paper, a novel optimal protection coordination scheme is proposed, one which enables a common optimal relay setting which is valid in both operating modes of the microgrid. In this context, a common optimal protection scheme is introduced for dual setting directional overcurrent relays (DOCRs) using a combination of various standard relay characteristics. Along with the two variables, i.e., time multiplier setting (TMS) and plug setting (PS) for conventional directional overcurrent relay, dual setting DOCRs are augmented with a third variable of relay characteristics identifier (RCI), which is responsible for selecting optimal relay characteristics from the standard relay characteristics according to the IEC-60255 standard. The relay coordination problem is formulated as a mixed-integer nonlinear programming (MINLP) problem, and the settings of relays are optimally determined using the genetic algorithm (GA) and the grey wolf optimization (GWO) algorithm. To validate the superiority of the proposed protection scheme, the distribution parts of the IEEE-14 and IEEE-30 bus benchmark systems are considered.

Protection Coordination Index Assessment Using Fuzzy Logic Controller

This paper proposes the assessment method of the protection coordination index (PCI) for overcurrent protection relay and upstream relay. The protection coordination index is an indicator of how properly the equipment is protected by protective relay. The PCI is used to check the appropriateness of the protection coordination for both the component-wise and pair-wise. The protection index of each protection component of the integrated digital relay is assessed by a fuzzy logic controller. Then the device-level protection index and the composite protection coordination index between up and downstream relays are also assessed. Since the setting criteria of the overcurrent relays are given in a certain range rather than a crisp value, it is difficult to indicate the protection level of the protective system as an index. Currently, there is no way of knowing how well the overcurrent relay setting is. Thus, a method was proposed to evaluate the protection index of overcurrent systems using fuzzy logic. This is the unique research result of this paper.

A Comprehensive Assessment of Fundamental Overcurrent Relay Operation Optimization Function and Its Constraints

The optimization of overcurrent relays’ operation is a topic associated with protection coordination of distribution networks. Usually, this refers to medium-voltage networks, since they are protected by numerical relay devices, as opposed to low-voltage networks, where utility operators allocate fuses. Correct setting of relays and optimal coordination is becoming a serious challenge to Distribution Network Operators around the world, since their networks’ passive operation has been greatly altered in the past two decades. Distributed generation units, a growing liberalized electricity market and more stringent legislation for distribution network planning and operation by state regulatory bodies have all indirectly affected the evolving of protection philosophy for distribution networks. In this paper the traditional optimization problem of overcurrent relay operation will be addressed and critically examined from both a theoretical and practical point of view. Optimization function, constraints and relay parameters will all be observed and compared with solutions used in distribution networks, and their modifications and improvements will be proposed and elaborated in detail.

Opportunistic Routing for Opto-Acoustic Internet of Underwater Things

Internet of Underwater Things (IoUT) is a technological revolution that could mark a new era for scientific, industrial, and military underwater applications. To mitigate the hostile underwater channel characteristics, this article considers a multimodal underwater network that hybridizes acoustic and optical wireless communications to achieve an ubiquitous control and high-speed low-latency networking performance, respectively. Since underwater optical wireless communications (UOWCs) suffer from limited range, it requires effective multihop routing solutions. In this regard, we propose a sector-based opportunistic routing (SectOR) protocol. Unlike the traditional unicast routing (TUR) techniques, which send packets to a unique relay, opportunistic routing (OR) targets a set of candidate relays by leveraging the broadcast nature of the UOWC channel. OR improves the packet delivery ratio as the likelihood of having at least one successful packet reception is much higher than that in TUR. Contingent upon the performance characterization of a single-hop link, we obtain a variety of local and global metrics to evaluate the fitness of a candidate set (CS) and develop candidate prioritization techniques for various OR metrics. Since rate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\leftrightarrow $ </tex-math></inline-formula> error and range <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\leftrightarrow $ </tex-math></inline-formula> beamwidth tradeoffs yield different CS diversities, we develop a candidate filtering and searching algorithm to find the optimal sector shaped coverage region by scanning the feasible search space. Moreover, a hybrid acoustic/optic coordination mechanism is considered to avoid duplicate transmission of the relays. Numerical results show that the SectOR protocol can perform even better than optimal unicast routing protocols in well-connected underwater networks.

Resource Allocation via Model-Free Deep Learning in Free Space Optical Communications

This paper investigates the general problem of resource allocation for mitigating channel fading effects in Free Space Optical (FSO) communications. The resource allocation problem is modeled as the constrained stochastic optimization framework, which covers a variety of FSO scenarios involving power adaptation, relay selection and their joint allocation. Under this framework, we propose two algorithms that solve FSO resource allocation problems. We first present the Stochastic Dual Gradient (SDG) algorithm that is shown to solve the problem exactly by exploiting the strong duality but whose implementation necessarily requires explicit and accurate system models. As an alternative we present the Primal-Dual Deep Learning (PDDL) algorithm based on the SDG algorithm, which parameterizes the resource allocation policy with Deep Neural Networks (DNNs) and optimizes the latter via a primal-dual method. The parameterized resource allocation problem incurs only a small loss of optimality due to the strong representational power of DNNs, and can be moreover implemented without knowledge of system models. A wide set of numerical experiments are performed to corroborate the proposed algorithms in FSO resource allocation problems. We demonstrate their superior performance and computational efficiency compared to the baseline methods in both continuous power allocation and binary relay selection settings.

Outer Bounds for Multiuser Settings: The Auxiliary Receiver Approach

This paper employs auxiliary receivers as a mathematical tool to identify Gallager-type auxiliary random variables and write outer bounds for some basic multiuser settings. This approach is then applied to the relay, interference, and broadcast channel settings, yielding new outer bounds that improve on existing outer bounds and strictly outperform classical outer bounds. For instance, we strictly improve on: the cutset outer bound for the scalar Gaussian relay channel, the outer bounds for the Gaussian Z-interference channel, and the outer bounds for the two receiver broadcast channel.

Protection of Microgrid Interconnection Lines Using Distance Relay With Residual Voltage Compensations

Protection of microgrids at the Point of Interconnection (POI) is a challenging task. Particularly, single-line-to-ground (SLG) faults on interconnection lines are difficult to detect using the fault current detection relays if the microgrid is ungrounded at utility side of its interconnection transformer; such microgrid contributes very low fault current, which disappears once the utility feeder breaker opens. Other common schemes for protection of microgrid interconnection line against SLG faults include Direct Transfer Trip (DTT) and over-voltage relay (59G). The main challenges associated with these methods are installation and maintenance costs of high-speed communication system, sensitivity of relay settings, and delayed fault clearing time due to selectivity requirements. To address such concerns, this paper proposes the use of a distance relay at the microgrid&#x002F;LV side of the interconnection transformer to provide protection against SLG faults on the interconnection line at the utility&#x002F;HV side. The designed distance relay executes an enhanced apparent impedance calculation using residual voltage compensation to correctly detect the fault, properly measure the fault location, and timely isolate the fault. In this paper, various scenarios are analyzed using ASPEN and PSCAD simulation tools to demonstrate the effectiveness of the proposed method for protecting the microgrid interconnection line under different fault scenarios.

The effect of breached relay ramp structures on deep‐lacustrine sedimentary systems

AbstractFault relay ramps are important sediment delivery points along rift margins and often provide persistent flow pathways in deepwater sedimentary basins. They form as tilted rock volumes between en‐echelon fault segments, which become modified through progressive deformation, and may develop through‐going faults that ‘breach’ the relay ramp. It is well established that hinterland drainage (fluvial/alluvial systems) is greatly affected by the presence of relay ramps at basin margins. However, the impact on deepwater (deep‐marine/lacustrine) subaqueous sediment gravity flow processes, particularly by breached relay ramps, is less well documented. To better evaluate the complex geology of breached relay settings, this study examines a suite of high‐quality subsurface data from the Early Cretaceous deep‐lacustrine North Falkland Basin (NFB). The Isobel Embayment breached relay‐ramp, an ideal example, formed during the syn‐rift and was later covered by a thick transitional and early post‐rift succession. Major transitional and early post‐rift fan systems are observed to have consistently entered the basin at the breached relay location, directed through a significant palaeo‐bathymetric low associated with the lower, abandoned ramp of the structure. More minor systems also entered the basin across the structure‐bounding fault to the north. Reactivation of basin‐bounding faults is shown by the introduction of new point sources along its extent. This study shows the prolonged influence of margin‐located relay ramps on sedimentary systems from syn‐rift, transitional and into the early post‐rift phase. It suggests that these structures can become reactivated during post‐rift times, providing continued control on deposition and sourcing of overlying sedimentary systems. Importantly, breached relays exert control on fan distribution, characterised by laterally extensive lobes sourced by widespread feeder systems, and hanging walls settings by small‐scale lobes, with small, often line‐sourced feeders. Further characterising the likely sandstone distribution in these structurally complex settings is important as these systems often form attractive hydrocarbon reservoirs.

Токоограничение в системе электропривода постоянного тока с модальным управлением и переменной структурой

Разработан и исследован эффективный метод ограничения тока в замкнутой системе электропривода постоянного тока с модальным управлением при различных режимах работы электродвигателя. В качестве объекта управления принят двигатель постоянного тока (ДПТ) независимого возбуждения с питанием от тиристорного преобразователя. Для решения поставленной задачи использованы методы теории автоматического управления. Исследован метод ограничения тока якорной цепи ДПТ в замкнутой системе с модальным управлением и переменной структурой. Произведен синтез коэффициентов модального регулятора тока и скорости вращения якоря ДПТ. Проведено моделирование переходных процессов пуска, торможения, реверсирования и стопорения ДПТ. Дана оценка качества процесса управления путем анализа переходных процессов замкнутой системы электропривода в среде моделирования динамических систем MatLab. Приведены рекомендации по выбору параметров релейных звеньев для обеспечения эффективного токоограничения. Выполнена проверка работоспособности системы электропривода при вариации параметров двигателя. В целом предложенный метод токоограничения успешно справляется со своей задачей, однако чувствителен к настройкам релейных элементов.

AN OPTIMIZED ADAPTIVE OVERCURRENT RELAY PROTECTION IN DISTRIBUTION SYSTEM USING CHAOS BASED SATIN BOWERBIRD OPTIMIZATION ALGORITHM (C-SBO)

The increased availability of protections of distributed system is a major role by ensuring the continuity of electrical power supply. The optimization process for a distributed system is to coordinate with overcurrent relay protection with adaptive overcurrent relay model. Here the protection of the system is an important factor since the protection methods play a vital role in distributed systems. The conventional methods discussed the current in the power system to reduce the fault current tolerance value by using various optimization algorithms like Antlion and Butterfly optimization techniques. The distributed three-phase system uses the IEEE bus network with adaptive overcurrent relay model, which produces the best output as compared to the conventional method. Here the particle swarm optimization (C-SBO) procedure is used to improve the relay setting and it reduces the fault current across the relay.

Improved Adaptive Protection Scheme Based Combined Centralized/Decentralized Communications for Power Systems Equipped With Distributed Generation

Recently, numerical relays with communication capabilities have been employed to provide adaptive solutions for Distributed Generations (DGs) protection issues. This paper presents an adaptive protection scheme based on centralized and decentralized communication to address DG protection problems. The proposed method uses two directional relays in each feeder, one at the beginning (called forward relay) and one at the end (called reverse relay). These relays can communicate with each other and the central unit. The centralized communication occurs between the central unit and the relays in the system when any relay’s status changes from connected to disconnected or vice versa. It aims to define the operation mode, islanding detection, and activate the relays settings to achieve proper coordination. Protective relays are coordinated using a Genetic Algorithm (GA) to optimize protection time. The optimization problem considers pick up current (Ipu), Time Multiplier Setting (TMS), Plug Setting Multiplier (PSM), and curve type. Decentralized communication, which occurs when any relay detects a fault, increases relays’ accuracy and speed of decision-making. This paper also proposes a novel method for detecting High Impedance Faults (HIF), a significant difficulty for protecting engineers as it draws a very low current that conventional overcurrent relays fail to detect in most cases. HIF is detected using wavelet transform, symlet 8, detail 2 (d2), and relay communication. On the IEC benchmark microgrid, the suggested algorithm is tested. ETAP is used for load flow analysis and short circuit analysis, whereas MATLAB is used for GA optimization, HIF modelling, and wavelet transform routines.

An Opportunistic Routing for Energy-Harvesting Wireless Sensor Networks With Dynamic Transmission Power and Duty Cycle

Opportunistic routing (OR) is widely used in energy-harvesting wireless sensor networks (EH-WSNs). The transmission power of sensor nodes in EH-WSNs is usually adjusted dynamically to make full use of the harvested energy. Many OR algorithms with dynamic transmission power adjustment have been proposed for EH-WSNs. However, fewer studies consider the non-bidirectional communication and the increase in packet retransmission and delay caused by the heterogeneous transmission power/radii. To this end, we propose an opportunistic routing algorithm for EH-WSNs with dynamic transmission power and duty cycle (ORDPD). It adjusts the transmission power of the sensor nodes at the end of each time slot, according to the predicted available energy. It also adjusts the transmission power and duty cycle of the sensor nodes in time slots if the nodes receive packets from other nodes outside their current transmission range. ORDPD also adopts an improved transmission model and information exchange mechanism to dynamically update relay sets and forwarding paths. A series of experiments were conducted to verify the effectiveness of the proposed algorithm. The experimental results demonstrate that the proposed ORDPD reduces non-bidirectional communication and retransmission significantly and performs better than its corresponding competitors.

Strategy for Optimal Grid Planning and System Evaluation of Networked Distribution Systems

The meshed network may become a standard for future distribution systems owing to its various benefits regarding voltage profile, reliability, losses, and the distributed generation (DG). Therefore, in Korea, there is a plan to introduce an advanced form of meshed network called a networked distribution system (NDS). This refers to a system with permanent linkages between four distribution lines (DLs) and N×N communication-based protection. To properly introduce NDS to an actual grid, this study proposes a strategy for optimal grid planning and system evaluation. Four different topologies and four practical indicators are explained. First, load imbalance is used to find the optimal grid that maximizes the load capacity. Second, line overload, fault current, and temporary overvoltage (TOV) were used to evaluate the necessity of load transfer, availability of circuit breakers, relay settings, and system stability. PSCAD/EMTDC were employed for the simulation. This study establishes the construction and evaluation guidelines of NDS for distribution system operators (DSOs).

Protection schemes for a battery energy storage system based microgrid

This paper evaluates directional and adaptive overcurrent protection schemes in microgrids. A microgrid supported by a centralised Battery Energy Storage System (BESS) is chosen for the study. The stringent PQ controller of BESS will not allow it to dissipate into a fault, during its charging mode, causing the conventional directional schemes to mal-operate. A direction estimation scheme using magnitude and angle of superimposed positive sequence impedance is proposed to address this issue in BESS. Further, two fault detection techniques are proposed for BESS integrated feeders. The Main Protection Unit (MPU) detects an internal fault when there is a mismatch in the direction of relays at either end of a feeder. The second scheme uses adaptive overcurrent relay settings. Since the fault current is limited with PQ control, the pickup current is calculated dynamically with this control. Whereas a fixed pickup current is chosen, when the BESS inverter is voltage controlled. Simulations have been carried out using MATLAB/SIMULINK software. The proposed schemes work well for bidirectional power flows and in grid connected and standalone modes of microgrid operation.

A Detailed Testing Procedure of Numerical Differential Protection Relay for EHV Auto Transformer

In power systems, the programmable numerical differential relays are widely used for the protection of generators, bus bars, transformers, shunt reactors, and transmission lines. Retrofitting of relays is the need of the hour because lack of proper testing techniques and misunderstanding of vital procedures may result in under performance of the overall protection system. Lack of relay’s proper testing provokes an unpredictability in its behavior, that may prompt tripping of a healthy power system. Therefore, the main contribution of the paper is to prepare a step-by-step comprehensive procedural guideline for practical implementation of relay testing procedures and a detailed insight analysis of relay’s settings for the protection of an Extra High Voltage (EHV) auto transformer. The experimental results are scrutinized to document a detailed theoretical and technical analysis. Moreover, the paper also covers shortcomings of existing literature by documenting specialized literature that covers all aspects of protection relays, i.e., from basics of electromechanical domain to the technicalities of the numerical differential relay covering its detailed testing from different reputed manufacturers. A secondary injection relay test set is used for detailed testing of differential relay under test, and the S1 Agile software is used for protection relay settings, configuration modification, and detailed analysis.

Setting and Testing of the Out-of-Step Protection at Mongolian Transmission System

Modern distance relays have integrated numerous protection functions, including power-swing blocking and out-of-step or pole-slip tripping functions. The main purpose of the power-swing blocking function is to differentiate faults from power swings and block distance or other relay elements from operating during stable or unstable power swings. Most power-swing blocking elements are based on traditional methods that monitor the positive sequence impedance rate. The required settings for the power-swing blocking elements could be difficult to calculate in many applications, particularly those where fast swings can be expected. For these cases, extensive stability studies are necessary to determine the fastest rate of possible power swings. This paper presents a detailed step-by-step method for settings calculation of out-of-step (OOS) protection, both blocking and tripping functions considering a generic two-source system. Then the method is applied to define the protection relay settings installed at the interconnection between the Russian and Mongolian power systems, as it is crucial to feed the demand-rich Mongolian power system. In this paper, a specific impedance method is used for defining the OOS protection settings. This paper innovates by testing the settings using the recordings of the major events of 15 September 2018 in two approaches: hybrid co-simulation and cyber-physical. Both tests have demonstrated the appropriate performance of the proposed settings and proving the proposed methodology works appropriately.