Time Multiplier Setting Research Articles

Analysis of War Optimization Algorithm in a Multi-Loop Power System Based on Directional Overcurrent Relays

In electrical power systems, ensuring a reliable, precise, and efficient relay strategy is crucial for safe and trustworthy operation, especially in multi-loop distribution systems. Overcurrent relays (OCRs) have emerged as effective solutions for these challenges. This study focuses on optimizing the coordination of OCRs to minimize the overall operational time of main relays, thereby reducing power outages. The optimization problem is addressed by adjusting the time multiplier setting (TMS) using the War Strategy Optimization (WSO) algorithm, which efficiently solves this constrained problem. This algorithm mimics ancient warfare strategies of attack and defense to solve complex optimization problems efficiently. The results show that WSO provides superior performance in minimizing total operating time and achieving global optimum solutions with reduced computational effort, outperforming traditional optimization methods (i.e., SM, HPSO, GA, RTO, and JAYA). The proposed algorithm shows a net time gains of 7.77 s, 2.57 s, and 0.8484 s when compared to GA, RTO, and JAYA respectively. This robust protection coordination ensures better reliability and efficiency in multi-loop power systems.

Analysis of Relay Coordination in Electrical Distribution Networks with Optimally Positioned Distributed Generation Units

As power demand increases and transmission and distribution capacity is limited, Distributed Generation (DG) units are gradually being incorporated into electrical power distribution networks. However, this integration may result in a significant impact on the coordination of protective relays, potentially generating issues such as blindness of protection and false tripping of overcurrent relays. To overcome these issues, an adaptive protection method is presented that adjusts relay sensitivity in response to changes in network design. The suggested technique dynamically modifies relay settings based on the line current, which fluctuates depending on the system design. Digital relays are needed for this method in order to save operational data in real time. Based on periodic observations, the Plug Multiplier Setting (PMS) and Time Multiplier Setting (TMS) parameters are optimized using a Fuzzy Inference System (FIS). Fuzzy rules are used by the adaptive algorithm for every relay. These rules are produced using the fuzzy editor using the inputs provided. An initial investigation was carried out to evaluate the effect of DG on the coordination of relay protection., as well as the optimal placement of DG to reduce losses and improve voltage profiles, using two base distribution networks. The algorithm was further tested on various configurations of IEEE distribution networks, and its effectiveness in achieving optimal relay coordination with adaptive settings was validated through the relay coordination module in ETAP.

Innovative protection schemes through hardware-in-the-loop dynamic testing.

In microgrid environments, the behaviour of Distributed Generation (DG) during fault conditions varies significantly based on DG types and penetration levels. Conventional Overcurrent Relays (OCRs) with standard time-current characteristics may exhibit limitations during excessive fault scenarios, leading to OCR operating delays and mis-coordination within the microgrid. This study proposes a novel constraint on the maximum Current Multiplier Setting (CMS) and utilizes Water Cycle Algorithm (WCA) and Particle Swarm Optimization (PSO) techniques to optimize the Time Multiplier Setting (TMS). Comparative dynamic analysis through real-time validation shows that the non-standard OCR approach outperforms the standard IEC scheme across all grid operation modes with different type, size and location of DGs. For instance, under F1 conditions, the tripping time of OCR1 was reduced from 0.0226 seconds (IEC) to 0.000981 seconds (non-standard). HIL results further affirm the efficacy of the proposed scheme. The optimization process, implemented in MATLAB and validated using ATP/EMTP simulations and SIPROTEC 7SJ62 relays, demonstrates enhanced microgrid protection coordination, improving system reliability and performance.

Optimal coordination of overcurrent relays in microgrids using meta-heuristic algorithms NSGA-II and harmony search

The emergence of distributed generation from renewable energy sources has led to the adoption microgrids as an alternative energy solution. However, implementing microgrids presents challenges, particularly in coordinating relay protection, due to factors like distributed generation sources, bidirectional power flow, variable short-circuit levels, and changes in network behavior. Although overcurrent relays (OCR) are frequently utilized in microgrid protection, a more adaptable strategy is needed as grid architectures transition from radial to non-radial. This paper proposes a new method to optimize the coordination of OCRs in microgrids by adjusting parameters like time multiplier settings (TMS), plug settings (PS), and characteristic curve selection. The study utilizes meta-heuristic techniques such as the harmony search algorithm (HSA) and the non-dominated sorting genetic algorithm-II (NSAGA-II) for optimal coordination. Simulations on a microgrid and bus test system demonstrate the effectiveness of the proposed approach in enhancing protection indicators like sensitivity, speed, selectivity, and reliability in microgrid operations. The results also indicate that the computation time of HSA is less than NSGA-II, but with an increase in DGs capacity, there is a continuous tendency to reduce the relay operation time.

Melaka Network Overcurrent Protection & Coordination Analysis Using PSCAD Software

This paper presents a study on the modeling of the 132/33/11kV PMU Pulau Gadong network and the Melaka radial distribution feeder. The study proposes a protection scheme by providing the appropriate relay Pickup current/Plug Setting (PS) and Time Multiplier Setting (TMS )/Time Dial Setting (TDS) for the discrimination process and evaluating the effect of parallel transformers during faults. For this study, the IEC std 255-3 standard inverse IDMT curve characteristic was chosen for the simulation using the Power System Computer Aided Design (PSCAD). The results show that these values were trustworthy, which provide adequate and reliable protection for the whole network.

Evaluasi Kinerja Sistem Proteksi Penyulang Trawas PT. PLN (PERSERO) ULP Pandaan

The primary objective of this research was to minimize disruptions in the feeder at ULP Pandaan by analyzing the coordination between recloser outgoing and incoming feeders. This study addressed the frequent issue of recloser trips, which caused instability in power supply. The purpose of this research was to provide conclusions and solutions to mitigate these disruptions. The methodology involved a detailed analysis of OCR (Over Current Relay) settings for protective devices on Trawas feeder. This included measurements of primary current settings and TMS (Time Multiplier Setting) values using both standard inverse and normal inverse configurations. Specific settings, such as 25518 A for the Trawas Recloser primary current and a TMS of 0.07, were determined to yield optimal performance. Additional settings for the Outgoing CB (Circuit Breaker) (357061 A, TMS 0.04) and the Incoming CB (181865 A, TMS 1.0) were also established. The important findings revealed that these settings significantly enhanced the reliability of the protective devices, ensuring better coordination between the recloser and CB systems. The implications of this research were substantial, as the optimized settings were expected to reduce the frequency and impact of feeder disruptions. This improvement in system reliability directly benefited both the electricity provider, PT. PLN (Persert), and the consumers by providing a more stable and efficient power supply. In conclusion, this study offered a comprehensive analysis and practical solutions for enhancing the protection system's performance on the Trawas feeder, which could be applied to similar electrical distribution networks to achieve better stability and reliability.

Optimal coordination of directional over current relays for distribution systems using hybrid GWO-CSA

Coordination of protective relays is a critical aspect of electrical distribution systems, ensuring effective and reliable protection against faults. In modern power systems, the integration of distributed generation (DG) sources adds complexity to the coordination task. The dynamic nature of DG systems requires adaptive relay settings that can swiftly detect and isolate faults while minimizing potential damage and downtime. The purpose of this research is to improve the coordination of directional over current relays in electrical distribution systems, particularly in DG systems. An optimization technique combining the grey wolf optimization (GWO) and cuckoo search algorithm (CSA) is developed to identify the best relay settings that reduce overall operation time while ensuring excellent fault identification and isolation. To address relay faults caused by DG integration, a suitable primary and backup relay design is chosen, and the influence of time multiplier settings (TMS) on system performance and reliability is investigated. The proposed GWO-CSA technique is evaluated and implemented on IEEE 3, 8 and 15-bus systems using MATLAB. Simulation results show that the GWO-CSA strategy outperforms well compared to previous algorithms, enabling optimal coordination and increased protection in DG systems while drastically lowering relay operating time.

Optimal coordination of directional overcurrent protection relays using hybrid optimizer

In order to minimize or maximize an objective function, electrical engineering problems might benefit from optimization methodologies inspired by nature. This study employs a hybrid particle swarm optimizer (HPSO) to get rid of local optimum solutions and find the best global one for directional overcurrent protection relays (DOPR) protection. DOPR coordination is a highly constrained, mixed-integral nonlinear optimization problem. An adaptive defense method has been created to counteract the intentionally challenging design. Therefore, design variables such as time multiplier setting (TMS) and plug setting (PS) are utilized for each relay in the circuit. The goal function is to reduce the amount of time spent to trace the fault by all the relays. Reducing the time required for each relay to trace the fault is the aim of function. After analyzing and comparing two test studies of the IEEE benchmark using various optimization strategies, we found that the results for the IEEE 15-bus system has minimum time of 8.9 s, which is improved by 22.92% to 82.89%, and those for the IEEE 30-bus system minimum time of 22.45 s that is improved by 4.41% to 39.6%. In terms of overall DOPR operation and computational time needed to get the global optimum solution, the acquired results are demonstrably superior to those obtained using conventional and state-of-the-art methods.

Coordination Tool for Overcurrent and Earth-Fault Relays at A 33/11 KV Power Distribution Substation in Basrah City

The coordination of overcurrent relay protection in the power framework is crucial for preserving electrical distribution systems. It ensures that both primary and backup protection are provided to the system. It is essential to maintain a minimal level of coordination between these relays in order to reduce the overall running time and guarantee that power outages and damage are kept to a minimum under fault conditions. Proper coordination between the primary and back-up relays can minimize the operation duration of overcurrent with instantaneous and earth fault relays by selecting the optimum TMS (Time Multiplier Setting) and PS (Plug Setting). The present study investigates the difficulty associated with determining the TMS and PS values of earth-fault and overcurrent relays at the 33/11 kV power distribution substation in Basra using the instantaneous setting element. Overcurrent and earth fault relays were simulated in two scenarios: one with a time delay setting and one with an immediate setting. This procedure was carried out to generate Time Current Characteristics (TCC) curves for each Circuit Breaker (CB) relay took place in the Nathran substation, which has a capacity of 2×31.5 MVA and operates at a voltage level of 33/11 kV. The substation is a part of the Basrah distribution network. The short circuit current is estimated at each circuit breaker (CB), followed by the simulation of protection coordination for the Nathran substation using the DIgSILENT Power Factory software. This research is based on real data collection, and the setting considers the short-circuit current at the farthest point of the longest feeders. The results show the effectiveness of the proposed coordination scheme, which reduced trip operation time by 20% compared to the presented case study while maintaining coordination between primary and backup protection.

Microgrid Protection Coordination Considering Clustering and Metaheuristic Optimization

This paper addresses the protection coordination problem of microgrids combining unsupervised learning techniques, metaheuristic optimization and non-standard characteristics of directional over-current relays (DOCRs). Microgrids may operate under different topologies or operative scenarios. In this case, clustering techniques such as K-means, balanced iterative reducing and clustering using hierarchies (BIRCH), Gaussian mixture, and hierarchical clustering were implemented to classify the operational scenarios of the microgrid. Such scenarios were previously defined according to the type of generation in operation and the topology of the network. Then, four metaheuristic techniques, namely, Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Invasive Weed Optimization (IWO), and Artificial Bee Colony (ABC) were used to solve the coordination problem of every cluster of operative scenarios. Furthermore, non-standard characteristics of DOCRs were also used. The number of clusters was limited to the maximum number of setting setting groups within commercial DOCRs. In the optimization model, each relay is evaluated based on three optimization variables, namely: time multiplier setting (TMS), the upper limit of the plug setting multiplier (PSM), and the standard characteristic curve (SCC). The effectiveness of the proposed approach is demonstrated through various tests conducted on a benchmark test microgrid.

Coordinated Overcurrent Relay Development with Arduino and ACS712

This study presents the design and evaluation of an overcurrent relay system using Arduino Uno, ACS712 current sensors, and electromagnetic relays. Conducted at the University of Negros Occidental–Recoletos, Philippines, from March 2023, the research focuses on developing a relay with accurate trip times and reliable performance. The designed relay features multiple characteristics including Standard Inverse, Very Inverse, and Extremely Inverse, with time delays ranging from 20 ms to 100 ms and time multiplier settings from 0.1 to 0.23. Testing results showed that the Extremely Inverse characteristic achieved the fastest trip time of 0.11 seconds at 9.3 A, while the Normal Inverse characteristic had a trip time of 1.04 seconds at 1.7 A. The relay's error margins were well within the 5% tolerance limit set by IEC 60255 standards, with errors ranging from 0.027 to 0.028. Effective coordination was achieved by adjusting the Time Multiplier Setting (TMS) values to ensure fault isolation without disrupting other system components. The results confirm that the relay design is both accurate and reliable, suitable for practical implementation in electrical protection systems. Future work could involve integrating additional functionalities and testing under diverse environmental conditions.

Adaptive overcurrent protection scheme coordination in presence of distributed generation using radial basis neural network

The operational performance of conventional overcurrent protection relay coordination connected to a distribution network is adversely affected by the penetration of distributed generators (DG) at different buses in the network. To address this problem, this paper proposes a novel adaptive protection coordination scheme using a radial basis function neural network (RBFNN), which automatically adjusts the overcurrent relay settings, i.e., time setting multiplier (TSM) and plug setting multiplier (PSM) based on the penetration of DGs. Short circuit currents and voltages measured at different buses are acquired using the remote terminal units (RTU) connected to different buses within the terminal network. Communication between the various remotes and local end station RTUs is through hybrid communication systems of fiber optic and power line communication system modules. The new adaptive overcurrent protection scheme is applied to the IEEE 33-bus distribution network with and without DGs, for single and multi-DG penetration using both the ETAP and MATLAB software. The simulation results show the proposed scheme significantly improves the protection coordination.

Coordination of protective relays in distribution systems considering uncertainty caused by renewables and demands based on orthogonal experiments

The operations of distribution systems are more challenging than in past decades because of the penetration of distributed generation (DG). Several serious problems may be caused by DG, such as bi-directional power flow in a distribution line, different levels of fault currents and uncertainty in power generation. This paper investigates the coordination of inverse-time overcurrent relays (OCRs) in distribution systems with uncertain distributed power generation and loads. A novel method is presented in this work, considering different scenarios along with two levels of uncertainty caused by DGs (photovoltaics and wind) and bus loads, to determine fault currents using Taguchi orthogonal experiments. Nonlinear optimization is then employed to find the optimal settings of inverse-time OCRs in distribution systems and to identify infeasible current transformer ratios. Simulation results obtained from a 9-bus system and a modified IEEE 33-bus system show that the proposed method outperforms the traditional point-estimation method (PEM). For the 33-bus system, the mean values of similarity indices based on the probability density function are obtained by the proposed method, and they are 0.979 and 0.975, which are closer to unity, for time multiplier setting (TMS) and pick-up setting (PS), respectively, than those (0.953 and 0.951 for TMS and PS, respectively) obtained by the PEM. The mean values of error indices based on the cumulative distribution function are obtained by the proposed method, and they are only 0.0007 and 0.0085 for TMS and PS, respectively, while those obtained by the PEM are 0.0011 and 0.0110 for TMS and PS, respectively.

Optimum Overcurrent Relay Coordination Using Genetic Algorithm with Time Multiplier Setting and Pick-Up Current Setting as Variables

Optimum Overcurrent Relay Coordination Using Genetic Algorithm with Time Multiplier Setting and Pick-Up Current Setting as Variables

Adaptive Directional Overcurrent Relay Coordination in Microgrid Considering Optimal Full Setting Parameters

This article proposes a novel approach for the optimal coordination of adaptive directional overcurrent relay (ADOCR) for modernized active distribution system (ADS) with microgrid (MG) functions. The goal is to keep the coordinating circumstances while reducing the protective relay operation time, as much as possible. With the proposed round-off mixed-integer particle swarm optimization (ROMI-PSO), the setting parameters are not limited to only relay time multiplier setting (TMS) and pickup current setting (PS) but can include the discrete parameter as relay characteristic curve setting (CS). In the proposed framework, The CS can be both IEC and IEEE standard curves in the proposed framework. Four buses radial system and IEC-benchmark MG system were used in a number of simulation experiments. Comparing the suggested methodology to other current methods revealed that it is more effective at determining the minimum relay operating times and ensuring the proper operation of protections under various fault allocations and operating circumstances.

Optimal Coordination of Directional Overcurrent Relays Using Hybrid Firefly–Genetic Algorithm

The application of directional overcurrent relays (DOCRs) plays an important role in protecting power systems and ensuring their safe, reliable, and efficient operation. However, coordinating DOCRs involves solving a highly constrained and nonlinear optimization problem. The primary objective of optimization is to minimize the total operating time of DOCRs by determining the optimal values for decision variables such as the time multiplier setting (TMS) and plug setting (PS). This article presents an efficient hybrid optimization algorithm that combines the modified firefly algorithm and genetic algorithm to achieve improved solutions. First, this study modifies the firefly algorithm to obtain a global solution by updating the firefly’s brightness and to prevent the distance between the individual fireflies from being too far. Additionally, the randomized movements are controlled to produce a high convergence rate. Second, the optimization problem is solved using the genetic algorithm. Finally, the solution obtained from the modified firefly algorithm is used as the initial population for the genetic algorithm. The proposed algorithms have been tested on the IEEE 3-bus, 8-bus, 9-bus and 15-bus networks. The results indicate the effectiveness and superiority of the proposed algorithms in minimizing the total operating time of DOCRs compared with other optimization methods presented in the literature.

Adaptive real-time protection scheme for distribution networks with high penetration levels of renewable energy resources

The increasing demands of electrical power have imposed a necessity to integrate renewable energy power sources (REPS) into electrical power networks. The presence of REPS within electrical distribution networks mandated an update in the settings of the overcurrent protection relays. In this paper, a real-time adaptive protection scheme is proposed to redefine the settings of the overcurrent protection relays by replacing the traditional time multiplier setting (TMS) with a newly proposed real-time adaptive time multiplier setting (ATMS). The proposed ATMS is formulated as the product of two factors namely; the acceleration factor (AF) and the tuning factor (TF). The AF is set as the ratio of the impedance seen by the relay during a fault to the pre-fault impedance. The TF is a multiplication constant that is determined offline prior to operation in order to optimize ATMS. The scheme was tested upon different radial and meshed bench-mark testing systems; the IEEE 34 system and the IEEE 30 bus system employing MATLAB software package. The proposed scheme proved its capability of optimizing the response of overcurrent relays and minimizing total operating time. In addition to its adaptability to different operational and loading conditions during the day.

Evaluation of Over Current Relay Settings Optimization for Multi-infeed DG-connected-grid

Increasing the short-circuit current magnitude and bidirectional flow in a multi-infeed DG-connected grid have significant impacts on protection systems based on over-current relays (OCRs). An adaptive protection scheme based on defining the optimal setting of a directional OCR (DOCR) has recently been introduced as a solution for mis-coordination and false tripping issues associated with DG penetration increase. In this paper, this approach is highlighted, and its performance in different operating modes of the DG-connected grid is evaluated. Genetic algorithm (GA), and gray wolf optimization (GWO) have been used to provide optimized values of the time multiplier setting (TMS) of the DOCR scheme. Different faults at different locations with different DG locations and sizes are studied. The international electrotechnical commission (IEC) micro-grid benchmark and different DG units are modeled with MATLAB Simulink and ETAP software to carry out and test all these operating modes and evaluate this scheme. The ability of this scheme to maintain the coordination between the forward and reverse main and backup relays for each fault location is focused on in this study.

An adaptive protection coordination strategy utilizing user-defined characteristics of DOCRs in a microgrid

• The present study discusses about the user-defined characteristics of DOCRs as a proposed method. • Here near end and far end fault points have been considered for observing the effectiveness of the proposed approach over conventional approach. • Different contingencies like generation increase or decrease have been considered and the proposed coordination strategy has been observed for its effectiveness. • Hybrid GA-NLP algorithm has been utilized for implementing the relay coordination task and a comparative study with GA and NLP algorithms for proposed and conventional approach has been discussed. • Three test systems namely IEEE 6 bus, modified 14 bus and IEEE 30 bus has been utilized for validation of the proposed study. The value of plug setting (PS) as well as time multiplier setting (TMS) of Directional Overcurrent Relay (DOCR) is used to achieve the relay coordination conventionally. With the emergence of Numerical DOCR, four settings of the relay, namely, PS, TMS, A and B are utilized for the relay coordination. This numerical DOCR make the coordination strategy adaptive for any contingencies. In this paper, four setting coordination strategy is proposed for Grid connected and for different contingencies in the network topology considering near end and far end fault locations. This coordination problem is formulated and solved using Hybrid GA-NLP approach. The proposed strategy is validated on the meshed distribution system. It also investigates the impact of DG penetration. The proposed method is also compared with the conventional strategy. The relay coordination problem has been tested on the meshed distribution system of IEEE 6-bus, modified 14-bus and IEEE 30-bus test systems which are penetrated with synchronous based DGs. The computed results show that the user-defined approach of selecting inverse time relay characteristic has significant potential in minimizing the overall operating time of the Numerical based DOCR. Hence, making it an effective and reliable option for meshed distribution system with DG.

Adaptive OCR coordination in distribution system with distributed energy resources contribution

<abstract> <p>More and more distributed energy resources (DERs) are being added to the medium-voltage (MV) or low-voltage (LV) radial distribution networks (RDNs). These distributed power sources will cause the redistribution of power flow and fault current, bringing new challenges to the coordination of power system protection. An adaptive protection coordination strategy is proposed in this paper. It will trace the connectivity of the system structure to determine the set of relay numbers as a tracking path. According to the topology of the system structure, the tracking path can be divided into two categories: the main feeder path and the branch path. The time multiplier setting (TMS) of each relay can be used to evaluate the operation time of the over-current relay (OCR), and the operation time of the relay can be used to evaluate the fitness of the TMS setting combination. Furthermore, the relay protection coordination problem can be modeled to minimize the accumulated summation of all primary and backup relay operation time (OT) subject to the coordination time interval (CTI) limitation. A modified particle swarm optimization (MPSO) algorithm with adaptive self-cognition and society operation scheme (ASSOS) was proposed and utilized to determine TMS for each relay on the tracking path. A 16-bus test MV system with distributed generators (DGs) will be applied to test the adaptive protection coordination approach proposed in this paper. The results show that the proposed MPSO algorithm reduces the overall OT and relieves the impact on protection coordination settings after DG joins the system. The paper also tests and compares the proposed MPSO with other metaheuristic intelligence-based random search algorithms to prove that MPSO possesses with increased efficiency and performance.</p> </abstract>