Protective Device Coordination Research Articles

Power Compatibility of Induction Motors in Industrial Grids Containing Synchronous Generators

Starting an induction motor causes voltage sag in the industrial grid that may disturb the operation of grid equipment. Direct-on-line starting is the simplest and most cost-effective method for starting induction motors, but also the most problematic. Large industries often use internal power plants with synchronous generators and starting powerful motors may impact the generator operations. The synchronous generators could be operated with the automatic or manual mode of voltage control. As the operation experience proves, the generator voltage control mode has a significant impact on the transient behaviours in the industrial power grid when starting a large induction motor. This article presents a case study of the synchronous generator tripping within a true medium-voltage industrial grid during the direct-on-line starting of a large induction motor driving the feed water pump. An analysis of the generator protection logs after the tripping showed that the synchronous generator was controlled in manual mode and its protection relay settings were exceeded. The transients initiated by induction motor starts were studied for possible configurations and operating conditions of the grid using a model developed on the Matlab/Simulink Software platform. The simulations have shown that concern about starting large motors in industrial grids containing internal synchronous generators needs to be solved considering the grid configurations and the coordination of generator protection and control devices.

Analysis the securable operation and protection coordination indices on multi‐objective sitting and sizing of synchronous distributed generations on distribution networks

AbstractDespite improving various technical indices such as operation and voltage profile, the integration of synchronous distributed generations (SDGs) may lead to the loss of protection coordination in the distribution network (DN). To tackle the problem, this paper presents a multi‐objective siting and sizing of SDGs on DN considering operation, economic and protection coordination indices simultaneously. The proposed scheme is structured in the framework of a four‐objective optimization problem, which aims to minimize the energy losses, the worst voltage security index (VSI), planning cost of SDGs and the protection index (PI) (the deviation of coordination time interval). Therefore, it is constrained to power flow equations, VSI, and protection coordination of overcurrent relays (OCRs). Then, the Pareto optimization based on the method of the weighted functions summation obtains an integrated single‐objective problem for the proposed scheme. Next, a hybrid evolutionary algorithm formed by merging particle swarm optimization (PSO) and crow search algorithm (CSA) is incorporated to achieve the optimal solution with unique response approximate conditions. Eventually, the suggested scheme is applied on distribution portion of IEEE 30‐bus ring and IEEE 69‐bus radial DN and numerical results confirm the efficient performance of SDG planning in terms of technical indicators and protective devices coordination.

Differential Protection Scheme for A Micro Grid with Inverter-Type Sources Based On Positive Sequence Fault Currents

The microgrid (MG) is a coordinated collection of different distributed generation (DG) typesthatsupply local demandthrough a distribution network. MG may operate in two different modes: grid-connected (GC), and islanded (IS)modes.The fault current valuevaries significantly between the GC and IS mode for a MG with inverter-based distributed generators(IBDGs). The fault currents are minimal in the IS mode owing to the power electronics equipment have a limited current carrying capacity. Therefore, the coordination of traditional overcurrent (OC) protection is difficult for these two operation modes. Therefore, a comprehensive MG protection scheme should be established to safeguard MG against all kinds of faults. The main protection strategy proposed in this paperis a positive sequence differential current protection scheme. The envisioned concept can overcome the protective device coordination problems, and all fault types can be detected during both operation modes of MG for radial andloop configurations. The validation of the proposed design is performed using PSCAD/EMTDC software. The results indicate that the maximum fault clearing time for the main protection in GC mode and IS modeisof 31.5 ms and 34 ms respectively. Compared with other schemes, the proposed scheme has a faster clearing time and is less expensive.

Electrical System of URSM Science and Technology Building: An Analysis

The main goal of this research was to evaluate if the existing power supply, which is three-phase, four-wire, and 400 volts, was safe and cost-effective. The study also intends to perform an Electrical System Analysis of the existing 400V, 3-phase, 4-wire power supply, including short circuit calculations, protective device coordination and protection, and arc-flash analysis. This research is based on the Philippine Standard of Electrical Design as it is applied and used by electrical professionals in the Philippines. Electrical System Analysis calculations are based on the National Electrical Code, IEEE Standards, and the most recent edition of the Philippine Electrical Code (PEC 2017). According to the findings, the URSM Science and Technology Building's current power supply is adequate and ready for future expansion. It was also cost-effective, as they discovered that the URSM's old ISR Building needed to be upgraded. The Short Circuit Analysis reveals that the installed protective devices' KAIC ratings are underrated and should be upgraded. The protective device coordination and protection reveals that the protective equipment must have a 0.2 to 1 second time setting. The required PPE for the building's electrical maintenance staff is shown in the arc flash analysis. This study's overall implications provide necessary inputs and corrective measures for the safety of URSM faculty, students, and other stakeholders.

Optimal Coordination of Protection Devices in Distribution Networks With Distributed Energy Resources and Microgrids

Microgrids are promising to enhance power distribution systems’ efficiency, quality, sustainability, and reliability. However, microgrids operation can impose several challenges to traditional protection schemes, like changes in the power flow direction and an increase in short-circuit currents. Microgrids can include several distributed generation technologies with different behaviours during short-circuit conditions, requiring additional protection schemes and devices. In this way, the optimized coordination of reclosers and fuses in distribution networks with directional overcurrent relays, which operate as interconnection devices, might overcome many imposed protection challenges. Regarding to different generation technologies, voltage-restrained overcurrent relays and frequency relays are presented as local microgrid protection for rotative and inverter-based distributed generators, respectively. The optimized coordination of these protection devices maximizes microgrid benefits and minimizes operation drawbacks by reducing interruptions impacts and energy not supplied to consumers. This work proposes, thus, a mathematical model for the optimal coordination of protection devices in distribution networks with distributed energy resources operating in grid-connected and islanded modes. The minimization technique of operating times using an elitist genetic algorithm with variable crossover and mutation processes is proposed, as well. The results show adequate coordination using passive and low-cost protection devices.

Adaptive Current Protection Technology for Distribution Network with Distributed Power Sources Based on Local Information

Because the distributed power supply is connected to the distribution network, its structure has also changed the original traditional method. The original single power supply method was originally used. The network provided is a radial network and it is connected to the distributed power supply. Later, it became a structure with small- and medium-sized power supplies inside, and its network power supply became dual or multiple power supplies. Such a structural change affected the coordination of power distribution protection devices, which would impose current on the distribution network. Protection has a negative impact. This paper aims to study the adaptive current protection technology of distribution network with distributed power based on local information. On the basis of analyzing the characteristics of distributed power, the classification of distributed power, and the operation mode of distributed power, according to the access of IIDG, as well as different influences of relay protection of distribution network, an improved protection scheme with adaptive current quick-break protection as the main protection is proposed, so that different fault characteristics of the distribution network have different setting values, and then simulation experiments are carried out on this scheme. The experimental results show that the setting value of three-phase short-circuit fault proposed in this paper can well protect the protection range, which is larger than the traditional protection setting and self-adaptive setting.

A model for simultaneous location and coordination of protective devices in radial distribution networks

Upgrading protection schemes in distribution networks can help electric utilities to improve the reliability of their supply. Fuses and reclosers are still the primary protective devices used in distribution grids, and their optimal allocation allows isolating faults with the least number of interrupted customers. However, most models used to select and locate protective devices optimally do not consider their coordination or rescue schemes for the fuses, resulting in unfeasible or impractical solutions. This paper presents a mixed-integer linear program model for the simultaneous selection, localization, and coordination of protective devices (reclosers and fuses), considering the fuses' rescue schemes based on electrical criteria. Local reliability indices and economic penalties for violating minimum standards are integrated into the model, thereby providing new decision-making elements. The proposed approach is tested in different distribution networks to showcase its key features. Computational experiments show that the proposed model can satisfactorily handle the trade-off between costs and reliability.

An offline three-level protection coordination scheme for distribution systems considering transient stability of synchronous distributed generation

The growing penetration of synchronous distributed generation (SDG) affects the protection and stability of power distribution systems. The connection of SDG to distribution network may lead to change in the amplitude and direction of the current of feeders during the fault conditions and thus disturb the coordination of protection devices (PDs). On the other hand, the transient stability of SDGs as low-inertia machines after fault occurrence strictly depends on the fault clearing time which relies on the performance of the protection system. Therefore, an effective protection scheme should simultaneously consider both aspects of protection coordination of PDs and transient stability of SDGs. In this paper, an efficient and comprehensive offline three-level protection scheme is proposed to consider both protection coordination and transient stability indices. In the first level, the transient stability of SDGs is assessed in terms of critical clearing time (CCT) using offline simulations. In the second level, PDs are coordinated considering clearing time interval (CTI) of the main and backup PDs and CCT of SDGs. Finally, in the third level, the characteristic curves of PDs are modified if required by the transient stability of SDGs. The effectivity of the proposed method is demonstrated using the simulations on an active IEEE 33-bus distribution network in the ETAP software.

Optimization-Based Formulations for Short-Circuit Studies with Inverter-Interfaced Generation in PowerModelsProtection.jl

Protecting inverter-interfaced microgrids is challenging as conventional time-overcurrent protection becomes unusable due to the lack of fault current. There is a great need for novel protective relaying methods that enable the application of protection coordination on microgrids, thereby allowing for microgrids with larger areas and numbers of loads while not compromising reliable power delivery. Tools for modeling and analyzing such microgrids under fault conditions are necessary in order to help design such protective relaying and operate microgrids in a configuration that can be protected, though there is currently a lack of tools applicable to inverter-interfaced microgrids. This paper introduces the concept of applying an optimization problem formulation to the topic of inverter-interfaced microgrid fault modeling, and discusses how it can be employed both for simulating short-circuits and as a set of constraints for optimal microgrid operation to ensure protective device coordination.

Various Metaheuristic-Based Algorithms for Optimal Relay Coordination: Review and Prospective

The coordinated or selective power system can be considered as a sequence procedure among two protective devices installed in series and having certain features. The coordination of protective devices in protection system is a very substantial procedure to guarantee a strength and reliable power system. Directional overcurrent relays coordination is considered as an optimization problem. Due to the difficulties that face this problem especially in multi-loop networks; it is a complicated challenge taking into account the problem constraints. An overview of various metaheuristic-based optimization methodologies is presented to get a proper solution for the coordination problem between each relay pairs to guarantee satisfactory relay settings. In addition, offering various methods of relay coordination, a comparison between earlier works is also performed. It's expected that this study will be helpful for researchers interested in this field.

Coordinated fuzzy logic‐based virtual inertia controller and frequency relay scheme for reliable operation of low‐inertia power system

Coordination between protection and control devices is crucial for maintaining continuous operation of power systems. Existing strategies suffer from improper coordination of control and protection devices. Moreover, high penetration levels of renewable energy sources result in lowering the overall power system inertia. Therefore, this paper presents a robust fuzzy-logic control (FLC) method for superconducting magnetic energy storage (SMES) in low inertia power systems. The new proposed FLC enables robust and wide operating range for SMES compared to the widely employed controllers. The proposed FLC method and load frequency control are coordinated to emulate virtual inertia. In addition, a cooperate coordination between frequency relay and proposed controller is preserved to maintain reliable operation of low inertia power systems. To prove the effectiveness of proposed coordination strategy, it has been tested with considering different load and renewable energy sources (RESs) disturbances with varying inertia level of the selected case study. The results demonstrate that the proposed FLC method can achieve robust SMES operation as virtual inertia controller (VIC) at wide operating range. Moreover, cooperative operation of VIC and frequency protection is preserved using the proposed coordination strategy. The power system availability, frequency regulation, and dynamic stability are improved using the proposed method.

Soft Computing Methods for Attaining the Protective Device Coordination Including Renewable Energies: Review and Prospective

The optimized coordination of directional over current relays (DOCRs) in power systems is still a challenging task. This optimization problem has been augmented in the literature through coping with various methodologies and the progress is not over yet. Thanks to the advance in technology, this task is mitigated in terms of time consuming and computational errors via applying different metaheuristic and nature inspired algorithms. Break points approach, distributed generations (DGs) penetration, mixed distance and DOCRs coordination, dual-setting DOCRs concept, transient stability constraint, and adaptive coordination represent most of the work performed by the researchers in the literature. However, some issues have not been tackled in this optimization process that deems a fertile ground needs tedious endeavors. This review article sheds the light on the most recently optimization approaches which are prevalent to deal with these highly constrained optimization problems. In the same context, many researchers are proposed various optimization frameworks to deal with coordination optimization problems aiming to have better performance and to define optimal relay settings. This review article is useful in the field of optimal relaying coordination of power systems with embedded DGs as it presents a comprehensive overview for many of the contributions of researchers in recent years. Detailed various formulations to represent the coordination problem with associated solution approaches are discussed and concluded.

Acceptable DG Capacity for Radial Distribution System Based on Traditional Protection Scheme (Dept.E)

Traditional electric distribution systems are radial in nature. These networks are protected by very simple protection devices such as over-current relays, fuses, and reclosers. Recent trends in distributed generation (DG) and its useful advantages perfectly can be achieved while the relevant concerns are deliberately taken into account. For example, penetration of DG disturbs the radial nature of traditional distribution networks. Therefore, protection coordination will be changed in some cases, and in some other cases it will be lost which is very costly in that two cases. In developed countries it could be cost effective if adding DGs network keeping the traditional protection system unchanged. To tackle that point of research, authors proposed technique to maintain the old protective devices coordination unchanged up to a specific DG penetration level. In this paper, a framework is presented for determining the maximum capacity of DG penetration level to keep traditional protection scheme for distribution network unchanged. Applying that framework in the developing countries could save money and time during the integration of DGs to the network on a large scale based on country regulation. The proposed framework is implemented on a simple distribution network using MATLAB SIMULINK and finally the numerical results are presented in order to validate the suggested framework.

Response of 10-kV Metal-Oxide Surge Arresters Excited by Nanosecond-Level Transient Electromagnetic Disturbances

Nanosecond-level transient electromagnetic disturbance (TED), including very fast transient overvoltage caused by operation of disconnectors, high-altitude electromagnetic pulse, and many other fast transients may interfere or even damage the electrical equipment. As one of the main overvoltage protective equipment, the protective performance of metal-oxide surge arresters (MOAs) under nanosecond-level TED should be investigated and then compared with that under microsecond-level TED, especially the lightning impulse. Based on a testing platform containing a 400-kV pulse generator with adjustable rise time from 5 to 100 ns, the behaviors of nonlinearity, fast impulse response, and converting impedances of three types of 10-kV MOAs under TED with different rise time were explored experimentally in this article. The peak residual voltages of 10-kV MOAs under TED with the rise time of 5 ns at 5 kA are 50.2-60.7% higher than those under the lightning impulse. The rise time of TED has significant influence on the peak voltage and impedance converting behaviors of MOAs. A circuit model of 10-kV MOAs under nanosecond-level TED is built and validated by experimental results, which can be applied in insulation coordination and design of protective devices against TED.

Protection system planning for distribution networks: A probabilistic approach

This paper presents a multi-objective optimization approach to perform the allocation, sizing and coordination of control and protective devices in distribution networks with different types of distributed generation. The model consists of three objective functions that consider investment costs, the system’s non-supplied energy, and average interruption duration index. We use a probabilistic short-circuit routine to evaluate the currents values, taking into account the uncertainties of renewable power generation and the system’s loading, as well as the fault’s parameters randomness. The probabilistic approach allows the correct planning of the protection system and enables the user to admit some risk of not coordinated operation, aiming to reduce the solutions’ costs. This multi-objective mixed-integer non-linear optimization problem considers the possibility of load transfers from neighboring feeders and intentional islanding. In this paper, we use the Non-dominated Sorting Genetic Algorithm to solve this optimization problem. The algorithm is tested for a 135-bus feeder.

Optimal Coordination of Overcurrent Relays Using Improved Leadership-Based Grey Wolf Optimizer

Coordination of overcurrent relays is a nonlinear and highly constrained optimization problem in a large distribution system where the operating time of all relays is to be minimized. Proper coordination of protective devices is a very crucial task for appropriate functioning of the electrical power system with distributed power generating stations. In order to solve this problem, various unconventional optimization techniques have been proposed. Random Walk Grey Wolf Optimizer (RW-GWO) is a recently developed algorithm based on improving the search ability of the leading wolves in classical GWO algorithm to overcome the issues of stagnation to local optima and premature convergence while solving nonlinear and complex optimization problems. Therefore, in the present work, RW-GWO algorithm is employed to find the optimal setting for directional overcurrent relay problem which is a highly complex problem. In the present paper, the results are also reported for classical GWO and the comparison is performed with several other optimization methods. The comparison of results demonstrates the strength of the RW-GWO in obtaining the optimal setting for the proper coordination of overcurrent relays as compared to other optimization methods.

Protection Coordination Toward Optimal Network Reconfiguration and DG Sizing

Research on network reconfiguration (NR) considering distributed generations (DG) is typically concerns on the issues of power loss, voltage deviation, DG sizing as well as its placement, which are important and required in the planning stage. On the other hand, another important aspect which often neglected in this stage is coordination of protection devices which is essential to prevent the network from damages following system breakdown. Without sufficient attention given to the protection coordination during NR, there is a possibility for the protective devices to miscoordinate and consequently lead to system blackout, due to changes in current flow and fault level. Therefore, this paper proposed an NR method for distribution networks with DG, incorporating protection devices. The proposed method aims to find the optimal configuration and DG size with minimum power loss, and at the same time ensuring protective devices operate correctly during normal and fault condition. Constraints on protection coordination and DG size are explicitly formulated in the proposed method. The validity of the proposed method is analyzed on three commonly used IEEE 33-bus, 69-bus and 118-bus distribution systems, employing the firefly algorithm (FA) and evolutionary programming (EP) algorithm. Comparative studies are done to prove the validity and robustness of the proposed method.

Coordination of surge protective devices in low voltage AC power installations

The surges protection in low-voltage AC power circuits is commonly realized by Surge Protective Devices (SPDs). These devices divert a large amount of the surge energy to the ground and reduce the surge voltage to the level acceptable for protected device(s). Adequate protection performances are provided by applying multiple-stage protection assuming cascade deployment of SPDs starting from distribution board toward equipment in an installation. Therefore, SPDs coordination, (i.e. selection of SPDs parameters as well as determination of necessary distance between stages) becomes of great importance and the paper deals with this issue. The proper SPDs coordination is significant for both protected equipment and SPDs themselves (their survival during surges). The paper provides an analysis of the SPDs coordination for case of two-stage protection system. The influence of different lengths of cables between protection stages, as well as influence of type and parameters of load on SPDs protection characteristics have been analyzed and discussed with the purpose of determination of requirements for proper surge protection and coordination of applied SPDs.

Analysis of Stage Difference Coordination of Protective Devices in Direct Current System

Stage difference coordination is an important part of DC system. Taking the GM series two-stage DC circuit breaker and the GMB series three-stage DC circuit breaker as examples, the protection characteristics of the DC circuit breaker are described. The 220kV substation is taken as an example to analyze the DC connection mode and protection analysis of the control loop and closing circuit. The analysis proves that the level difference plays an important role in the stability of the DC system. This paper provides a reliable basis for perfecting the stage difference coordination of the power system in DC systems.

Fault Current Limiter Placement to Reduce Recloser ‑ Fuse Miscoordination in Electric Distribution Systems with Distributed Generation using Multiobjective Particle Swarm Optimization

This paper presents a method to minimize protective devices in electric distribution systems with Distributed Generation (DG). With the growing penetration of DG in distribution systems, the main practice to maintain protective devices coordination during a fault is to disconnect all DG sources. This practice nullifies the benefits brought by DG in distribution systems, mainly because the majority of faults are proven to be temporary. To solve this problem, this paper proposes the allocation of fault current limiters (FCL), which consist in inert devices on system's normal operation, but insert a high impedance value in series with feeders when a fault occurs, thus, limiting is magnitude. FCL placement is treated as a multiobjective optimization problem, aiming to reduce fault currents difference between situations with DG and without DG penetration. Also, FCL size must be minimized, aiming to reduce costs. The search for the optimal solution is made using multiobjective particle swarm optimization and the method is tested on the Canadian Benchmark Test System, showing great efficiency.