Operating Time Of Relays Research Articles

OPTIMASI KOORDINASI OVER CURRENT RELAY PADA TRAFO 60 MVA 150/20 KV DAN PENYULANG 20 KV GUMUL GARDU INDUK BANARAN BERBASIS PARTICLE SWARM OPTIMIZATION

Abstract
 At Banaran Transformer Substation 60 MVA 150/20 kV, the problem that often occurs is a short circuit fault. Short circuit fault sometimes causes the 20 kV Gumul Feeder to go out, so that the incoming safety of the 60 MVA transformer is also affected. This is because the coordination of the relay between the 20 kV Gumul feeder OCR and the 60 MVA incoming transformer OCR is less selective in isolating the disturbance which causes the relays not to overlap (not overlap). Therefore, to improve the performance of OCR coordination, it is necessary to set optimal OCR using the PSO method. The results of this study indicate the value of the OCR setting on the feeder side using PSO produces a TMS of 0.1197 s 
 with a relay operating time of 0.2471 s faster than the conventional results obtained by a TMS of 0.1453 s with a relay operating time of 0.300 s. So that the results of the PSO resulted in an increasing CTI of 0.3529 s, while the results from the conventional method obtained a CTI of 0.300 s. Based on these results it can be concluded that the coordination of the relay between the 20 kV Gumul Feeder OCR and the 60 MVA incoming transformer OCR can work quite selectively by isolating the disturbance appropriately.
 
 Keywords — Coordination, Short Circuit, OCR, PSO, TMS

Augmenting protection coordination index in interconnected distribution electrical grids: Optimal dual characteristic using numerical relays

One of the most significant tasks of protection coordination of power networks is the satisfaction of coordination between protective equipment. With growing penetration level of distributed generations)DGs), selectivity issue of overcurrent relays is very imperative in active distribution systems .Therefore, sustainable electricity needs to enhance the protection coordination index (PCI). These enhancement will cause the development of DG penetration in power networks. In this paper, time-current-voltage characteristics and dual-setting directional overcurrent relays (DOCRs) are jointly deployed to improve PCI in interconnected distribution networks where the coordination process seems a complex problem. Dual-setting relays can trip in forward and reverse directions with individual settings in both directions which provide proper flexibility to improve PCI. Also, time–current-voltage characteristics employ the voltage parameter in operation time of relays which can decrease the optimization process to cause higher flexibility in the coordination process. besides, the mentioned protection model is developed by user-defined time–current-voltage characteristics to improve PCI. The suggested scheme is modeled and presented as a nonlinear programming approach that is tackled by the genetic algorithm (GA) and comparing performance with Grey Wolf Optimization (GWO). In this paper, to evaluate the performance and scalability of the proposed method, IEEE 14-bus and 30-bus system is applied. The advantage of the proposed scheme is the ability to implement in numerical relays, in which paper is expressed in the form of protection logic and description of respective logic blocks. Results depict the significant improvement in PCI.

Per-Phase and 3-Phase Optimal Coordination of Directional Overcurrent Relays Using Genetic Algorithm

Penetration of the power grid by renewable energy sources, distributed storage, and distributed generators is becoming increasingly common. Increased utilization of these distributed energy resources (DERs) has given rise to additional protection coordination concerns, particularly where they are utilized in an unbalanced manner or where loading among phases is unbalanced. Digital relays such as the SEL-751 (produced by Schweitzer Engineering Laboratories, Pullman, WA, USA) series have the capability of being set on a per-phase basis. This capability is underutilized in common practice. Additionally, in optimization algorithms for determining relay settings, the time-overcurrent characteristics (TOCs) of relays are generally not treated as variables and are assigned before running the optimization algorithm. In this paper, TOC options themselves are treated as discrete variables to be considered in the optimization algorithm. A mixed integer nonlinear programming problem (MINLP) is set up where the goal is to minimize relay operating times. A genetic algorithm (GA) approach is implemented in MATLAB where two cases are considered. In the first case, the TOC and Time dial setting (TDS) of each relay is set on a three-phase basis. In the second case, per-phase settings are considered. Relay TDSs and TOCs are both considered as simultaneous discrete control variables. Despite the stochastic nature of using per-phase settings for unbalanced systems is found to generally allow for shorter operating times. However, for relatively balanced systems, it is best to use three-phase settings if computation time is of importance.

Slime mould algorithm constrained by the relay operating time for optimal coordination of directional overcurrent relays using multiple standardized tripping curves

In this paper, a new stochastic optimizer called slime mould algorithm (SMA) for solving the optimal coordination of directional overcurrent relays in meshed power networks is proposed. The proposed SMA-based method deals with the coordination problem using the most recent digital relays by selecting the optimal tripping standardized curve plus time dial and current pickup. Afterwards, the problem gets more sophisticated by bounding the relay tripping time inside a practical range to simulate the real network conditions. SMA’s performance is evaluated on two different test cases including highly penetrated distributed generators in the second one. The results of SMA are compared with other recent metaheuristic and conventional approaches reported in the literature under same conditions aimed at fair comparisons. It is declared that the SMA attains 29.9% reduction in the relays total operating time for the first test case compared to the well-matured water cycle algorithm. Even, if the tested network is a highly penetrated by distributed generators, more reduction is achieved by 33.7% with better convergence characteristics. It can be established that the SMA-based method demonstrates a competitive and reliable tool for minimizing the relays total operating time satisfying all the constraints even for the sophisticated scenarios.

Optimal coordination of over current relay using opposition learning-based gravitational search algorithm

In this paper, the optimum coordination of over current relay in distribution system has been performed. The time dial setting (TDS) of over current relay is optimized by minimizing total operating time of relays. As the power system is a complex and highly interconnected, the complexity may be occurred in calculating optimum relay coordination time (TDS, phase setting etc.) by conventional or analytical methods. Therefore, an opposition learning-based gravitational search algorithm (OLGSA) is proposed for relay coordination optimization problem. The proposed optimization method can search the optimum solution for relay coordination problem from both the direction (initial populations and their opposite direction populations) in search space to reach global solution as early as possible. Three different distribution power systems are considered to verify the performance of the proposed algorithm for optimum relay coordination problem. The simulation results for all three cases have been compared with existing results. The outcome of the proposed method for relay coordination problem shows that the total relay operating time is minimized (20–40 % improvement in relay total operating time for different cases) comparably than available results for all three cases by maintaining coordinations among relays and satisfying different constraints.

User-Defined Dual Setting Directional Overcurrent Relays with Hybrid Time Current-Voltage Characteristics-Based Protection Coordination for Active Distribution Network

With the penetration of renewable energy sources based distributed generation (RES-DG) in the distribution network (DN), the operating time of protection relays becomes a major concern to avoid the mis-coordination and nuisance tripping of RES-DG. It is due to the bidirectional flow of current, variance in the fault current level, i.e. high fault current in case of Squirrel cage induction generator (SCIG) based RES-DG, and low fault current for an inverter-based RES-DGs. This paper proposes a novel User-defined dual setting direction overcurrent relay with hybrid time current-voltage (UDDOR-TCV) characteristics to intensify the proposed scheme’s flexibility without any communication assistance for radial DN. The proposed model is formulated in a constrained non-linear optimization fashion and solved with the MINLP solver of general algebraic modelling system(GAMS) software to determine the optimal relay settings. The propounded protection scheme is simulated on IEEE-33 bus radial distribution system and a local 40-bus system hosting the multiple SCIG and PV based RES-DGs at optimal locations. Detailed numerical studies are carried out to show the performance of the proposed scheme. 66.848% and 68.26% reduction in relay operation time with zero mis-coordination is achieved with SCIG-WTG case and PV-units case for the IEEE-33 bus system and a similar reduction in operation time is 68.937% and 66.563% for Local-40 bus system. Moreover, the relays numbers are reduced by 32.692% and 39.7% for IEEE-33 and Local-40 bus systems, respectively, due to the forward/reverse characteristics capability of the proposed UDDOR-TCV. The performance of the proposed scheme is also evaluated on IEEE-8 bus meshed DN. The results are compared with the existing protection schemes in recent literature.

Optimal Coordination of Directional Overcurrent Relays in Meshed Active Distribution Network Using Imperialistic Competition Algorithm

The optimal setting of directional overcurrent relays (DOCRs) ensures the fault detection and clearing in the minimum possible operation time. Directional protective relaying is carried out to coordinate relay settings in a meshed network in the presence of distributed generation. The main goal of DOCR coordination is to find the optimal time dial setting (TDS) and pickup multiplier setting (PMS) to reach the minimum total operation time of all primary relays in the presence of coordination constraints. Due to the complexity of mixed integer non-linear programming (MINLP) problem, imperialistic competition algorithm (ICA) as a powerful evolutionary algorithm is used to solve the coordination problem of DOCRs. The proposed DOCR coordination formulation is implemented in three different test cases. The results are compared with the standard branch-and-bound algorithm and other meta-heuristic optimization algorithms, which demonstrates the effectiveness of the proposed algorithm.

Optimal Protection Coordination Scheme for Radial Distribution Network Considering ON/OFF-Grid

Technology advancement for renewable energy resources and its integration to the distribution network (DN) has garnered substantial interest in the last few decades. Integrating such resources has proven to reduce power losses and improve the reliability of DN. However, the growing number of these resources in DN has imposed additional operational and control issues in voltage regulation, system stability, and protection coordination. Incorporation of various types of distributed generators (DG) into DN causes significant changes in the system. These including new fault current sources, new fault levels, a blinding effect in the protection scheme, reduction in the reach of relays, and decrement in the detection of low-level fault currents for existing relays. Such changes will jeopardize the effectiveness of the entire protection scheme in the DN. This research aims to propose a robust protection scheme in which the relay coordination settings are optimized based on the network layout. The potential impacts of DGs on the DN are mitigated by utilizing a user-defined overcurrent-based relay characteristic to obtain the minimum operating time while satisfying protection coordination constraints. A hybrid optimization algorithm based on Metaheuristic and Linear Programming that has the capability to attain the optimal solution and reduces computational time is proposed in this work. The performance of the proposed technique is tested on radial DN integrated with microgrid (MG). The results obtained show the proposed technique has successfully reduced the relay operating time while meeting the protection coordination requirements for dynamic operating modes of a network.

Optimal dual characteristics for enhancing coordination index in protecting forward and reverse fault currents

Satisfying coordination constraints among protective devices is a challenging task in the protection system of electrical grids. On the other hand, increasing interest on the distributed generations (DGs) jeopardizes the selectivity among overcurrent relays in active distribution networks. Therefore, sustainable electrification requires enhancing the protection coordination index (PCI) in order to increase DG penetration in these networks. In this paper, time–current–voltage​ characteristics and dual-setting directional overcurrent relays (DOCRs) are jointly employed to improve PCI in interconnected distribution networks. Dual-setting relays can operate in forward and reverse directions with individual settings in both directions which help to provide more flexibility in improving PCI. Moreover, the time–current–voltage​ characteristics have the voltage parameter in operation time of relays which can simplify the optimization process to yield higher flexibility in the coordination process. Furthermore, the proposed protection scheme is extended by user-defined time–current–voltage​ characteristics to improve PCI as much as possible. The proposed scheme is formulated as a nonlinear programming model that is solved by the genetic algorithm (GA). The proposed scheme is tested on IEEE 14-bus and 30-bus testbed. Results show a remarkable improvement.

Research, design, manufacture leakage current protection device for 660V/1140V underground mine electrical networks

This paper presents the results of researching, designing and manufacturing leakage current protection device for 660 V/1140 V ungrounded three-phase electrical networks. The outstanding features of the device are: ability to create wide deformation characteristic; automatically detect and grounded the leakage phase. Device test results show that relay operation time ​​for symmetrical and asymmetric leak resistors are 30 kΩ/60 kΩ per phase and 20 kΩ /50 kΩ for 660 V/1.140 V networks respectively. The total operating time of the device when single phase leaking through a 1 kΩ resistor not exceed 105 ms. The circuit automatically detects and accurately grounded the leakage phase through 100 Ω resistance, the total detection and grounded the leakage phase time does not exceed 110 ms. This research result can be applied in the design and manufacture of high-quality and reliable leakage current protection devices used in underground mines, replacing imported products.

A Robust Adaptive Overcurrent Relay Coordination Scheme for Wind-Farm-Integrated Power Systems Based on Forecasting the Wind Dynamics for Smart Energy Systems

Conventional protection schemes in the distribution system are liable to suffer from high penetration of renewable energy source-based distributed generation (RES-DG). The characteristics of RES-DG, such as wind turbine generators (WTGs), are stochastic due to the intermittent behavior of wind dynamics (WD). It can fluctuate the fault current level, which in turn creates the overcurrent relay coordination (ORC) problem. In this paper, the effects of WD such as wind speed and direction on the short-circuit current contribution from a WTG is investigated, and a robust adaptive overcurrent relay coordination scheme is proposed by forecasting the WD. The seasonal autoregression integrated moving average (SARIMA) and artificial neuro-fuzzy inference system (ANFIS) are implemented for forecasting periodic and nonperiodic WD, respectively, and the fault current level is calculated in advance. Furthermore, the ORC problem is optimized using hybrid Harris hawks optimization and linear programming (HHO–LP) to minimize the operating times of relays. The proposed algorithm is tested on the modified IEEE-8 bus system with wind farms, and the overcurrent relay (OCR) miscoordination caused by WD is eliminated. To further prove the effectiveness of the algorithm, it is also tested in a typical wind-farm-integrated substation. Compared to conventional protection schemes, the results of the proposed scheme were found to be promising in fault isolation with a remarkable reduction in the total operation time of relays and zero miscoordination.

Towards energy transition: conjoint assessment of large-scale PV system performance and interconnection impacts in isolated microgrid

Environmental, energy security and electricity demand concerns stimulate solar-grid integration. However, intermittent, non-dispatchable PV characteristics may challenge passive grid operation. This paper contains the comprehensive planning and assessment of a 2 MWp CdTe-based PV system deployment proposed for hybrid operation in an isolated 11 kV 10-bus microgrid in Brunei. The presented approach combinedly assesses PV system performance and scenario-based interconnection impacts based on a detailed PV system model considering deployment conditions. Various interconnection points with multiple sets of feeder-specific measured load profiles are examined. Results show the PV system designed for maximum annual generation achieves performance ratio of 90.6%. While time-series power flow assessment reveals grid operation enhancement, there are concerns at times of generation-demand mismatch requiring proper genset sequencing and reactive power management. Meanwhile, faster relay operating time and reverse fault current are demonstrated in existing protection scheme. Dynamic grid stabilities are preserved in various generation intermittency and loss events, including the most challenging condition of further inertia and spinning reserve reduction reaching a frequency of 96.02%. Finally, optimal interconnection point fulfilling multi-objectives on losses, voltage profile and line reserve capacity is identified. The findings indicate a good prospect of the synergy for advancing energy transition. The analysis could facilitate RE planning and policymaking.

Towards energy transition: conjoint assessment of large-scale PV system performance and interconnection impacts in isolated microgrid

Environmental, energy security and electricity demand concerns stimulate solar-grid integration. However, intermittent, non-dispatchable PV characteristics may challenge passive grid operation. This paper contains the comprehensive planning and assessment of a 2 MWp CdTe-based PV system deployment proposed for hybrid operation in an isolated 11 kV 10-bus microgrid in Brunei. The presented approach combinedly assesses PV system performance and scenario-based interconnection impacts based on a detailed PV system model considering deployment conditions. Various interconnection points with multiple sets of feeder-specific measured load profiles are examined. Results show the PV system designed for maximum annual generation achieves performance ratio of 90.6%. While time-series power flow assessment reveals grid operation enhancement, there are concerns at times of generation-demand mismatch requiring proper genset sequencing and reactive power management. Meanwhile, faster relay operating time and reverse fault current are demonstrated in existing protection scheme. Dynamic grid stabilities are preserved in various generation intermittency and loss events, including the most challenging condition of further inertia and spinning reserve reduction reaching a frequency of 96.02%. Finally, optimal interconnection point fulfilling multi-objectives on losses, voltage profile and line reserve capacity is identified. The findings indicate a good prospect of the synergy for advancing energy transition. The analysis could facilitate RE planning and policymaking.

Optimal Overcurrent protection for industrial medium voltage network (Dept. E)

Abnormal condition and faults in power systems can cause power supply interruption and sometimes equipment damage. Hence, there is an increasing need for an effective protection scheme. In order to obtain a secure and reliable protection system, an effective coordination has to be satisfied between backup and primary protection devices. The main objective of this paper is to select the optimal settings of overcurrent relays that achieve the minimum operating time for relays when subjected to abnormal conditions or faults. The coordination process between overcurrent relays inside the network is accomplished considering detecting the fault and tripping the nearest circuit breaker to disconnect the affected area without affecting other areas. This paper investigates the protection requirement of switchgears in a practical power plant and design a coordination set for all circuit breakers and overcurrent relays in the low and medium voltage areas. In addition, both linear programming and genetic-algorithm methodologies are used to optimize the values of time dial setting for different operating scenarios of power plants so as to achieve the minimum operating times of overcurrent relays.

Considering DGs Voltage Protection in Optimal Coordination of Directional Overcurrent Relays to Minimize the Energy Not Supplied

So far, the overall operation time of relays has been used as the objective function in all directional overcurrent relays (DOCRs) optimal coordination problems. However, it cannot guarantee that in an optimal coordination of DOCRs at presence of distributed generations (DGs), the reliability indices will reach the minimum value. The reason is the existence of DGs voltage protection at their connection point to the network. This protection plays a key role in determining participation of DGs in improving network reliability during fault conditions. However, in the previous studies in which the overall operation time of relays is considered as the objective function, the voltage protection of DGs is not taken into account. In this article, coordination between DOCRs and their interactions with the DGs voltage protection is considered in calculation of the energy not supplied (ENS). Also, instead of the overall operation time of the DOCRs, the ENS value is considered as the optimization objective function. A probabilistic hourly seasonal model has been used to model the renewable DGs and the network loads. Various scenarios have been simulated to demonstrate the efficiency of the proposed method over a standard 33-bus radial distribution network.

Optimal coordination of directional overcurrent relays in complex distribution networks using sine cosine algorithm

The modern power distribution networks are very complex due to the growing integration of distributed generators in recent years. Optimal coordination of directional overcurrent relays (DOCRs) used for protection of such complex networks is a highly constrained and nonlinear optimization problem. In this paper, a new optimization algorithm called Sine Cosine Algorithm (SCA) is used first time to solve the optimal coordination problems of DOCRs. SCA is a recently proposed population-based algorithm used for solving highly nonlinear optimization problems. The cyclic pattern of sine and cosine function allows a solution to be re-positioned around another solution. This can guarantee exploitation of the space defined between solutions. The effectiveness of SCA in solving the optimal coordination problems of DOCRs is tested on different fault data generated on 3-bus, 8-bus, 15-bus and 30-bus test systems. The results clearly show that the effectiveness of the proposed algorithm is superior in reducing the overall operating time of primary relays compared to the recently published optimization algorithms for DOCRs coordination. Also, the proposed algorithm is robust in maintaining the coordination between primary and backup relay pairs. Compared to existing optimization algorithms, the proposed algorithm has reduced coordination interval time between primary and backup relay pairs.

Considering transient state in interconnected networks during fault for coordination of directional overcurrent relays

The object of optimal coordination in networks is to obtain the minimum operating time (OT) of directional overcurrent relays and to maintain the coordination time interval. Coordination of relays in the steady state causes miscoordination in practice. Conventional methods have some drawbacks such as ignoring the exact formula of the relay, using the simplified model of the network elements (ignoring complete models and nonlinear elements), and disregarding backup relays chain and fault current redistribution during topology transient change. In this study, a coordination method is proposed that considers the transient state by simulating the network using a complete model of the elements and precise formulas. Network simulation was performed in three stages in Simulink during the coordination. A new method is also proposed to obtain and correctly indicate the backup relays OTs incorporating the topology transient change. Initially, using one conventional method, the IEEE 8-bus and IEEE 30-bus networks were coordinated. The results show 23 and 94 miscoordinations, respectively. Moreover, since relays’ OTs show some errors, they were then coordinated using the proposed method. Consequently, all miscoordinations were eliminated and error-free OTs of relays were obtained. This study confirms that the proposed method has more practical results compared to conventional methods.

Improvement of Traditional Protection System in the Existing Hybrid Microgrid with Advanced Intelligent Method

The sustainable power sources will turn out to be a long haul future arrangement over conventional existing accessible source. Numerous specialized difficulties are ascending in the developing system of the Indian Microgrid; protection is one of it. Traditional protection framework utilized directional overcurrent transfers for the assurance against different deficiencies. These are dependent on the presupposition of the unidirectional progression of Current. The similar strategy cannot matter to the microgrid security as a bidirectional progression of current streams because of the nearness of DGs, which prompts specialized difficulties in the Microgrid. The new advanced intelligent method of DWT-differential Algorithm proposed over traditional protection system. The various parameters such as PS (Plug setting), TS (time setting), CDS(current duration setting) and operating time of relay tested. Indian Microgrid concentrated as contextual analysis, and smart system of microgrid protection prescribed to defeat all challenges got from writing contemplated. The system is designed in MATLAB software ,Double line to ground fault is simulated at different locations and DWT-DA is applied.The percentage of reduction obtained in operating time and other parameters are results in increasing reliability of microgrid.

Optimal protection coordination in the micro-grid including inverter-based distributed generations and energy storage system with considering grid-connected and islanded modes

This paper presents the optimal protection coordination (OPC) to grid-connected and islanded micro-grid (MG) consisting renewable energy sources (RESs), and energy storage system (ESS). The proposed approach considers objective function as minimizing the total operation time of the dual setting overcurrent relays (DSORs) in primary and backup protection mode. Problem constraints are the regulation parameters limits of the DSROs, sizing limit of FCLs and also the coordination time interval (CTI) inequality. MG includes generally RESs and ESS, hence, this problem needs to the daily optimal operation results of MG in both grid-connected and islanded modes to obtain the network variables before the fault occurrence. Therefore, it is minimized the MG operation and load shedding costs of islanded MG while it is constrained to MG optimal power flow equation in the presence of RESs and ESS. The proposed OPC includes non-linear model, hence, this paper uses the crow search algorithm (CSA) to obtain a reliable and optimal solution for this formulation. Finally, this strategy is implemented on the 9-bus and 32-bus MGs, thus, it can obtain the high quick protective solution for these MGs by selecting optimal regulation parameters and sizing to DSORs and FCLs, respectively, according to numerical results.

Coordination of directional overcurrent and distance relays based on nonlinear multivariable optimization

To ensure stability, security, and protection of electrical equipment from the damage the suitable coordination must be made in interconnected networks. In this paper, the nonlinear multivariable optimization techniques have been used with different performance indexes: Sequential quadratic programming (SQP), Sequential quadratic programming legacy (SQP-Legacy), Interior-Point and Active-Set for IEEE- 8 bus test system. This system consists of twenty-eight protective relays divided into fourteen directional overcurrent relays (DOCR) and fourteen distance relays (DR). It has been tested in the ETAP environment to obtain three-phase short circuit current at the near and far end faults and operating time for all DOC relays for near-end fault as well as test the second zone time for distance relays (TZ2) with pilot signal (WP)and without pilot signal (WOP) of the proposed algorithm was used to reduce overall operating time of DOC relays and obtain optimal values for time multiplier setting (TMS) and TZ2 with the different coordination time interval (CTI) between main and backup relays. The simulation results were validated in ETAP program prove that the effectiveness of the Active-Set to minimize the TMS and TZ2 for the system.<em> </em>