Adaptive Protection Coordination Research Articles

Adaptive protection coordination in microgrid based on nature inspired meta-heuristic optimization algorithm

Ensuring a robust protection system is crucial for safeguarding the integrity of the overall system against abnormalities. Incorporating distributed generation (DG) into the distribution network can introduce fluctuations in fault current levels and directions, potentially causing mismatches in the response of the existing coordination system. This study proposes an adaptive protection coordination scheme designed to accommodate both grid-connected and standalone modes, addressing various fault scenarios. Utilizing a hybrid WCMFO algorithm, optimal relay settings are determined to facilitate effective coordination within a microgrid setup. The proposed method has been analyzed on 9 bus Canadian benchmark system integrated with four DGs. The performance of the proposed method is compared to other optimization techniques to demonstrate its effectiveness. System modelling is conducted using MATLAB/Simulink, and validation is further carried out using industrial ETAP software on a test microgrid system. The analysis extends to evaluating the enhancement in overall system reliability, quantified in terms of energy not supplied (ENS).

Design of adaptive protection coordination scheme using SVM for an AC microgrid

Microgrids have gathered a significant amount of attention within the past decade and becoming an essential asset in the energy industry. The ability to integrate sustainable renewable energy generation into the distribution network is one of the main reasons for microgrids' popularity. Besides technical advantages, renewable energy sources integration with the grid poses many technical challenges. Due to randomness in generation and different modes of operation, integrating renewable energy sources into power systems will be challenging. Reliable operation of renewable energy sources integrated microgrids even when faults occur, requires an adaptive protection scheme and relay coordination. In order to tackle those issues, this paper developed an adaptive protection coordination scheme using numerical overcurrent relays and support vector machines with a particle swarm optimization approach. Renewable energy sources based on microgrids use power electronics systems that require relays to operate in milliseconds, and the power system will be safe. particle swarm optimization's program execution time exceeds the primary relays. The machine learning algorithm is faster in computation time. This article proposes a method, particle swarm optimization, to estimate the optimum relay operating time. The machine learning model having a support vector machine is proposed to estimate the relay operating time. The proposed research is developed and tested on an IEEE12BUS and IEEE35BUS system. The support vector machine -based on adaptive protection coordination schemes estimates the operating time of directional overcurrent relays, with a lesser program execution time and a low percentage error rate. The derived result defined that the proposed approach is well-suitable for real-time applications of an AC microgrid system.

An adaptive protection coordination for microgrids utilizing an improved optimization technique for user-defined DOCRs characteristics with different groups of settings considering N-1 contingency

Due to the increased integration of distributed generation (DG) in electric power systems, optimal coordination of overcurrent relays has become a key problem in power distribution systems. However, there is a lack of expertise in the creation of optimum microgrid coordination that takes into account all N-1 scenarios through the nonstandard relay characteristics. This work presents a novel technique for optimal coordination of directional overcurrent relays (DOCRs) in terms of relay curve settings (A and B), time dial setting (TDS) and plug setting (PS) to achieve the shortest running time and attain optimal settings. The optimization is carried out using a modified version of the Hanger Games Search algorithm (MHGS). The performance of the proposed method is assessed using the 14 bus distribution system while considering all the N-1 contingencies. DIgSILENT software was utilized to perform the required power system analysis, such as power flow and short circuit analysis. The MHGS method is used to determine the best settings for the DOCRs problem. The results are compared to the traditional HGS as well as those obtained by other current optimization approaches provided in the literature in order to demonstrate the effectiveness and superiority of the proposed MHGS in lowering relay operation time for optimum DOCRs coordination.

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.

Optimal Adaptive Protection Coordination with Inter-Trips and Setting Groups for Meshed Distribution Grids

Increasing distributed generations (DGs) penetration and their plug & play operation challenge the protection coordination of distribution networks due to variable fault current levels. Adaptive protection schemes as a great solution are used to cope with DGs connection status, where the DGs statuses are transmitted to relays via communication links to activate the appropriate Setting Groups (SGs). In this paper, a new hybrid protection scheme is introduced where it is composed of relays with SGs and inter-trip links to develop more sensitive adaptive protection. In the first stage, a sensitivity index is introduced to find the critical constraints and form a set of candidate relays. Then, a new method is proposed to assign the SGs and inter-trips according to the inter-trip effect on coordination restoration. Inter-trips restore the coordination with reducing primary relay operating time reduction, whereas SGs delay the operation of the backup relays. Optimal coordination of the proposed hybrid scheme is simulated on the IEEE 30 Bus distribution grid and compared with other schemes. The results indicate that the proposed hybrid scheme is a more efficient tool to improve the performance of the protection scheme under plug & play operation of DGs achieving lower fault clearance times.

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>

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.

Optimized adaptive protection coordination of microgrids by dual-setting directional overcurrent relays considering different topologies based on limited independent relays’ setting groups

• Optimal adaptive protection, considering the limits on the number of setting groups. • Using the DS-DOCRs incorporating independent changes in the setting groups. • Optimal relay curve types and breakpoints for the DS-DOCRs. • Fast protection without selectivity constraint violations in various configurations. • Around 41.66% improvement compared to available studies. Several studies, such as adaptive protection schemes, have been done in the area of smart grids’ protection. However, there is a research gap in developing an adaptive scheme with dual-setting (DS) directional overcurrent relays (DOCRs), considering the limitations of the number of setting groups of protective relays. This research aims to fill such a research gap. Optimizing the relay curve types of the first and second parts of the DS relay models and breakpoints (BPs) improves the speed of the protection scheme based on independent changes in the setting groups of DOCRs. Also, there is no coordination constraint violation in various configurations by applying the proposed method, while it requires only a limited number of setting groups. Therefore, the proposed method can be practical in actual systems because the suggested solutions and protective settings can be easily implemented using commercial relays. The proposed adaptive protection scheme is applied to two test systems (the distribution networks of the IEEE 14-bus and IEEE 30-bus test systems). The comparative test results infer that significant improvement in the speed of the protection system of smart grids can be achieved compared to available studies by the proposed method.

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.

An adaptive protection coordination scheme for microgrids with optimum PV resources

Nowadays, microgrids provide several economic and environmental benefits for customers, investors, and power networks. Their practical implementation, however, has several technical challenges such as energy management, control, and protection. The protection coordination is a crucial problem in microgrids with high penetration of renewable-based distributed generations such as photovoltaic units. In previous studies, despite the network's need for maximum photovoltaic resources, the installed capacity of these resources was assumed to be constant and limited due to the miscoordination of protective devices as a result of increasing network short-circuit level. This paper presents an optimal adaptive protection coordination scheme in microgrids with optimum penetration levels of photovoltaic resources without dependency on communication infrastructures, such as ways of communication between relays and central control room for analyzing all relay signals depends on fault condition and changing the setting step in adaptive relays. The proposed methodology can generally increase the penetration level of photovoltaic resources while minimizing the generation costs of photovoltaic resources by optimizing the installation capacity of each bus. The proposed adaptive protection coordination is achieved without changing the settings of existing protective devices. The optimal capacity of photovoltaic resources is updated through optimization algorithms such as non-dominate storing genetic algorithm considering several constraints including loss and cost minimization and voltage limits.

Adaptive Protection Coordination Method Design of Remote Microgrid for Three-Phase Short Circuit Fault

Generally, the fault current supplied by inverter-based renewable energy sources (IBRES) and electrical storage systems (ESS) is about 1.2 to 2 times their rated current and much lower than synchronous generators because the former acts as a current source and the latter acts as a voltage source. A conventional power system in a small island is composed of only synchronous generators and protected from short circuit faults using an overcurrent relay (OCR). However, in the remote microgrid with IBRES, ESS, and synchronous generators, the fault current varies depending on the configuration of generation sources. Namely, the fixed OCR protection method cannot protect microgrids from short circuit faults. This paper proposes an adaptive protection method to protect the microgrid from faults by actively changing the OCR setting according to the state of the generator source combination. A microgrid with ESS and a synchronous generator is modeled and simulated through PSCAD/EMTDC software to validate the proposed adaptive protection method.

Adaptive protection coordination scheme in microgrids using directional over-current relays with non-standard characteristics

Protection coordination of AC microgrids (MGs) is a challenging task since they can operate either in grid-connected or islanded mode which drastically modifies the fault currents. In this context, traditional approaches to protection coordination, that only consider the time multiplier setting (TMS) as a decision variable may no longer be able to guarantee network security. This paper presents a novel approach for protection coordination in AC MGs that incorporates non-standard characteristic features of directional over-current relays (OCRs). Three optimization variables are considered for each relay: TMS, maximum limit of the plug setting multiplier (PSM) and standard characteristic curve (SCC). The proposed model corresponds to a mixed integer non-linear programming problem. Four metaheuristic techniques were implemented for solving the optimal coordination problem, namely: particle swarm optimization (PSO), genetic algorithm (GA), teaching-learning based optimization (TLBO) algorithm and shuffled frog leaping algorithm (SFLA). Numerous tests were run on an IEC MG as well as with the distribution portion of the IEEE 30-bus test system. Both systems incorporate distributed generation (DG) and feature several modes of operation. A comparison was made with other MG protection coordination approaches proposed in the specialized literature. In all cases, the proposed approach found reduced coordination times, evidencing the applicability and efficacy of the proposed approach.

A q component‐based adaptive protection coordination optimisation using overcurrent relays in coordination with fuses for hybrid microgrid

In a hybrid microgrid, the overcurrent relays (OCRs) must sense the changes in the fault currents while the microgrid switches from the grid-connected to the islanded mode of operation. Further, for the different types of distributed generator (DG), such as photovoltaic (PV), wind turbines of types I, III, and IV, the variation in fault currents must also be detected by the relays. This leads to delay and inappropriate coordination in conventional protection schemes. To minimise the impact of inappropriate coordination in this study, an adaptive protection scheme with optimal settings is proposed for phase and earth faults detection. It also takes care of different nature of DGs, all feasible operating modes of hybrid microgrid with only quadrature (q) component of fault current while zero component is used to differentiate between earth and phase faults. Also, only q component-based proposed technique optimises the coordination time (CT) of fuses as a backup to primary and backup relays with newly proposed CT interval constraints. A differential evolutionary algorithm is proposed for determination of optimal settings for the directional OCRs.

A novel adaptive protection coordination scheme for radial distribution networks in the presence of distributed generation

A novel adaptive protection coordination scheme for radial distribution networks in the presence of distributed generation

Decentralized Adaptive Protection Coordination Based on Agents Social Activities for Microgrids With Topological and Operational Uncertainties

A decentralized adaptive scheme is proposed in this article for protection coordination for microgrids with topological and operational uncertainties. This protection coordination scheme is performed in two stages. In the first stage, a traditional fault protection is deployed to clear the fault. If the fault is isolated successfully, the protection system returns to the regular fault-free state. If the fault is not cleared due to operational uncertainties in the protection system, the second stage of protection coordination is initiated. In this stage, based on a federation structure, a set of agents around the fault location negotiate to reach the best protection coordination strategy upon the occurrence of a single or multiple fault(s). Considering the operational uncertainties of the respective circuit breakers and communication links, the best fault clearance strategy is determined by analyzing the probability of correct operation of all proposed strategies and considering the least number of probable load outages. Two major factors impacting the probability of correct operation are fault currents flowing through the respective circuit breakers and the latency of the communication links. The efficiency of the proposed scheme is demonstrated by comparing the simulation results with their experimental counterparts and those obtained using the conventional centralized and decentralized adaptive methods.

Adaptive protection scheme for microgrids based on SOM clustering technique

Microgrids are penetrating into the power systems at an unprecedented rate. The reason is the mutual economic and environmental benefits of microgrids, both for power grid utility and the consumers. Some special features of microgrids such as, the two main operational conditions called, islanded and grid-connected modes, and being composed of various types of distributed energy resources along with different uncertainties cause some tough challenges to protection and control systems. From the protection aspect, the coordination of overcurrent relays protection will become a difficulty, due to the extensive changes in the fault current levels sensed by these devices. In this paper, a new adaptive protection coordination scheme based on Self-Organizing Map (SOM) clustering algorithm is proposed for digital overcurrent relays equipped with several setting groups. Considering the similarity of mis-coordinated relay pairs for the clustering purpose, the proposed protection scheme focuses on solving the mis-coordination between main/backup relay pairs. As a case study, a modified IEEE 33-bus test system is used as a microgrid. In the case study, a synchronous distributed generation and two electric vehicle charging stations are installed. The results suggest that not only the proposed method is fully capable and flexible to significantly improve the mis-coordination of overcurrent relay pairs, but it can also ameliorate the operating time of relay.

Adaptive Protection Coordination with Setting Groups Allocation

Abstract- Distributed Generations (DGs) plug & play operation changes the fault current levels, which results in Directional Over-Current Relay (DOCR) miss-coordination and non-optimal tripping times. Adaptive protection is a great solution to tackle the adverse effects of DGs on distribution network. Some adaptive protection coordination for all DG connection statuses requires vast communication infrastructure and equipment upgrade where the non-adaptive coordination leads to high operating time of relays. In this paper, a new adaptive protection concept is introduced as a tradeoff where the settings of some relay are adaptively changed based on its neighborhood DGs connection. The number of Settings Groups (SGs) of each DOCR are found by calculating the proposed sensitivity matrix. The SGs are only added in relays experiencing the high changes in short circuit levels. The proposed method is simulated on IEEE-30 Bus and the results indicate the capability of the proposed method in efficient and optimum design of adaptive protection schemes with proper SGs allocation.

Adaptive Protection Coordination Scheme Using Numerical Directional Overcurrent Relays

Dynamically changing distribution system operating conditions compromises the coordination of the existing protection schemes. This paper proposes an online adaptive protection coordination scheme by utilizing numerical directional overcurrent relays (DOCRs) and commercial A Mathematical Programming Language (AMPL) based Interior Point OPTimization (IPOPT) solver. The proposed scheme also utilizes intelligent electronic devices and a communication channel to obtain real-time system information and to update relays settings. The presented approach is able to handle different operating conditions of the system, including loss of loads, generations, and lines. Further, the miscoordination arising due to injections of distributed generations (DGs) is also handled. The proposed approach has been tested on the IEEE 14-bus system (with and without DG), under various operating conditions. Overall system reliability enhancement using the proposed approach has been analyzed in terms of the amount of energy not supplied. Further, the optimum settings of DOCRs obtained using AMPL based IPOPT solver has been compared with those obtained by General Algebraic Modeling System based Sparse Nonlinear OPTimizer solver, OPTI Toolbox based IPOPT solver, MATLAB based interior point method, and metaheuristic genetic algorithm and differential evolution. It has been found that the proposed coordination approach gives good results in reasonably small time and thus, is suitable for the adaptive protection scheme.

Adaptive protection coordination scheme against the staircase fault current waveforms in PV‐dominated distribution systems

Photovoltaic (PV) systems, as distributed energy resources, can adversely affect the coordination of the protection system in distribution circuits. Various approaches have been presented in the literature to solve this problem, but none of them has proposed a solution for the staircase current waveforms seen in PV-dominated distribution systems. As there is insufficient time to apply new settings to a protection device following a fault, the appropriate solution should be to adaptively modify the characteristic curves in advance of the fault. Accordingly, using the voltage profile as a pre-fault index for current waveform, this study suggests an adaptive approach to efficiently modify the protection settings before the fault occurrence. To this end, first, an offline technique is used to calculate the best appropriate group setting corresponding to each voltage profile. Second, in real time and according to the voltage profile, an online algorithm applies the predefined group settings to the corresponding protection devices. Simulation results demonstrate the effectiveness of the proposed method on a practical network such that by applying the proposed technique, settings on programmable protection devices can be readily modified to improve on their coordination.

Adaptive protection coordination scheme for distribution network with distributed generation using ABC

This paper presents an adaptive protection coordination scheme for optimal coordination of DOCRs in interconnected power networks with the impact of DG, the used coordination technique is the Artificial Bee Colony (ABC). The scheme adapts to system changes; new relays settings are obtained as generation-level or system-topology changes. The developed adaptive scheme is applied on the IEEE 30-bus test system for both single- and multi-DG existence where results are shown and discussed.