Overcurrent Protection Research Articles

A Fast Overcurrent Protection IC for SiC MOSFET Based on Current Detection

A Fast Overcurrent Protection IC for SiC MOSFET Based on Current Detection

Design of Laser-Powered Opto-Electrical Current Transformer and Its Application in Electrical Automation of Substations

The novel power equipment represented by the Opto-Electrical Current Transformer (OECT) possesses unparalleled advantages compared to traditional Current Transformers (CTs), rendering it with vast potential in power systems. In the design of OECT, this study employs laser power supply and focuses on the overall perspective, particularly the design of the laser power supply module and the optical fiber digital transmission module. The laser power supply module selects a high-power semiconductor laser to provide power to the circuit, incorporating line filters, thermistor resistors, and a laser overcurrent protection circuit. An automatic temperature control circuit based on PI regulation is utilized to stabilize the working temperature of the laser diode (LD). The photoelectric conversion device PPC-6E achieves a maximum photoelectric conversion efficiency of 40%, and the MAX639 DC–DC conversion chip ensures stable output voltage. The optical fiber digital transmission module adopts a circuit composed of multiple NOR gate logic for electro-optical conversion, a low-power driving circuit based on the 74LVC1G07 chip, and the HFBR-2412 photoelectric converter to simplify the circuit board design. To achieve a higher communication baud rate, a quartz multimode optical fiber with a diameter of 62.5 μm is chosen. In the experimental phase, a simulation of high-power AC power with equal turns is conducted. The linearity/temperature test results demonstrate that the designed OECT in this study meets expectations. In the electrical automation test of substations, a comparison between traditional CTs and the designed OECT is carried out using traditional protection algorithms and optical differential protection algorithms. The results indicate that, compared to traditional protection algorithms, the optical differential algorithm using the designed OECT achieves faster protection times.

Output voltage tracking control of DC–DC boost converters with overcurrent protection

Output voltage tracking control of DC–DC boost converters with overcurrent protection

A Review on Power System Faults and Overcurrent Protection of Distribution Transformer

An electrical fault is the deviation of voltages and currents from nominal values. Power system equipment or transmission lines carry normal voltages and currents which results in smooth operation of the system. But when a fault occurs, it causes very high current to flow through the equipment and can damage the equipment. This paper provides the causes, effects and methods to overcome the faults of power system. Keywords— Power system; Current; Short Circuit; Faults; Power system protection; Equipment; Circuit breaker; Relay

OPTIMAL LOCATION AND SIZING OF DG IN DISTRIBUTION NETWORK: IMPACT ON OVERCURRENT DISTRIBUTION PROTECTION SCHEME

The integration of distributed generation (DG) into the existing distribution networks minimizes active power losses and improves the voltage profile. The recent improvement in the development of DG technology has caused increase in the penetration of DG from different sources. The optimal location and sizing of DG is very challenging and introduces different protection issues. This is caused by penetration of current flow from different source which is contrary to the principles of operation of the conventional overcurrent scheme. This paper presents optimal method of DG placement and sizing using firefly algorithm and its impact of DG penetration on overcurrent protection scheme. Low voltage distribution network is modelled and simulated in PSCAD/EMTDC and DigSilent power factory software using IEEE 33 and Ayepe 34 standard bus. False tripping of feeders, Nuisance tripping, blinding of the protection scheme and unintentional islanding caused as result of Photovoltaic penetration into the distribution network were simulated. Coordination of overcurrent relays with and without DG penetration were analyzed and possible mitigation algorithm were proposed. The simulation result obtained showed that the proposed methods significantly improve the protection scheme coordination..

SOLAR POWERED OFF-GRID WATER DISTRIBUTION PROJECTS: A CASE STUDY COMPARISON OF TWO COMMUNITIES

This paper presents the pre-construction planning and construction installation phases of student-run projects in Ecuador and Ghana to provide fresh water via pumped water storage through photovoltaic (PV) systems. Our Ecuadorian project relied on a preliminary design prepared by a non-profit organization as the construction basis. The Ghanian project was designed by students, with faculty support. These two case studies were chosen because they had similar project goals, occurred close in time, and had the same faculty and student clubs performing the work. The fundamental project management areas of scope, schedule, and budget management were assessed as a basis for comparison. Although there were several differences between the projects, students gained new knowledge in all of these areas. The work involved several students and two faculty from California Polytechnic State University, San Luis Obispo (Cal Poly). The work included piping connections to direct current submersible pumps, water storage, distribution piping/connections to a village community center or directly to households, PV panels, and an electrical distribution system with overcurrent protection. The initial design was an important part of each project; however, many details were resolved during construction using a design-build approach.

An optimal cyber–physical attack strategy on DC microgrids

This paper proposes an optimal attack strategy against Direct Current MGs (DCMGs). In the proposed strategy, attackers first eavesdrop on the data communicated between a target converter and the MG Control Center (MGCC) to model (i) the converter by its state-space representation using system identification techniques, and (ii) the rest of the system by its Thevenin equivalent circuit using the least-square method. Afterwards, the obtained model is used in an optimal control framework to design a False Data Injection Attack (FDIA) that controls the converter’s output to achieve the attackers’ objective, e.g., triggering the overcurrent or under-voltage protection of the converter. The proposed framework fulfills the objective while minimizing the rate of change of the converter’s voltage and the required control effort during the FDIA (to keep the attack stealthy) in the presence of the attack constraints. Such an attack strategy provides cyber-security experts with insight into potential attacks and their impacts on the operation and stability of DCMGs, and helps them to design and test their cyber-security measures more effectively. Simulation results in MATLAB/Simulink corroborates the effectiveness of the proposed attack strategy.

Resource-saving microprocessor-based reed switch current protection

We suggest designing a cutoff and an overcurrent protection for 6–35 kV electrical installations with switchgear cubicles on the basis of reed switches and a microprocessor without current transformers. A reed switch is a small glass tube with plates inside, which contact under the action of the corresponding magnetic field. Two reed switches are mounted near each busbar inside a switchgear cubicle at a safe distance using specially designed structures. The magnetic induction which acts on them is determined by the Biot–Savart law with experimentally found coefficients. The effect of currents in neighboring electrical installations and in switchgear cubicle casings is taken into account. We have developed and describe here an algorithm of protection operation and a technique for selecting parameters and estimating protection sensitivity. Such protections are noise-resistant due to detection of short circuits by the third actuation of a read switch; they detect a failed component with the help of built-in diagnostics. The test diagnostics is performed by means of supplying current simultaneously to the control windings of two reed switches, and the functional diagnostics, by means of supplying current to them in turn. The efficiency of such protections is confirmed by the simulation results.

Design of 3-Phase Load Dividing Automatic System with Naive Bayes Method

The electric power distribution system is a process for distributing electricity from a 150 kV electric power transmission system to consumers, both 20 kV consumers and 380/220 V consumers. The problem that often occurs in the electric power distribution system at PT.X is load imbalance due to the different consumption power on each phase, so a neutral current appears. The current flowing in the neutral phase will cause power losses. Based on these problems, a load balancing device was made for a three-phase network with the standard SPLN No. 17 of 2014, namely the magnitude of the value of the current imbalance between the phases may not exceed 25%. This tool is also equipped with an overcurrent protection system and a tapping phase limitation system to support the performance of the load-balancing device on a three-phase network. The method used is the Naive Bayes method. The naïve Bayes method calculates the current parameters in the R, S, T, and N phases. The classification results will be used as a reference for activating the tapping phase system and the protection system. This system uses Internet of Things technology to monitor neutral current, current and voltage values in phases R, S and T, and power loss values. Based on the test results, when there is an imbalance of 30.20%, a neutral current of 1.20A appears, causing a power loss of 0.17W. After the tapping phase is carried out, the percentage of unbalance is reduced to 12.20%, the neutral current is 0.45A, and the power losses are 0.02W.

Dual LC parallel multi‐resonant DC‐DC converter with wide output‐voltage range

SummaryAlthough LLC converters have widespread applications due to their advantages of high efficiency, high power density, and soft switching, in wide voltage gain range applications, a large switching frequency range is inevitably required, which may bring difficulties in converter design and efficiency improvement. In this paper, a dual LC parallel multi‐resonant converter (MRC) is introduced. The converter contains two parallel LC resonant branches in the resonant tank, which exhibit the notch filter characteristic on the gain curve. It enables the converter to provide wide voltage gain regulation, soft startup, and overcurrent protection over a limited frequency range. Compared to other five‐element MRCs, since the converter provides different current loops for the fundamental wave and the third harmonic to transmit active power, the circulating reactive energy and stress on the resonant components are reduced. Finally, a detailed design procedure for a 3.3 kW converter prototype with an output voltage range of 250–450 V is provided.

Analysis of fault current contributions from small‐scale single‐phase photovoltaic inverters and their impacts on the protection of electric power distribution systems

AbstractThis paper presents an analysis of the fault current contributions of small‐scale single‐phase photovoltaic inverters under grid‐connected operation and their potential impact on the protection of distribution systems. To conduct this analysis, an autotransformer‐based voltage dip generator is proposed as a means to test the photovoltaic inverters' contribution to short‐circuit currents. Laboratory tests are then performed to obtain the short‐circuit current contribution of eight single‐phase photovoltaic inverters. Using the short‐circuit current data obtained, a behaviour model is developed and simulated on Matlab‐Simulink. The model is then applied to a real distribution system and case studies are conducted to simulate the potential impacts on the protection system. Results indicate that while the massive penetration of small‐scale single‐phase photovoltaic inverters can alter the protection system's operating time, the impacts are not significant. Only in very specific scenarios, such as events related to high impedance faults, some impact can be observed. In these situations, the presence of photovoltaic inverters further complicates the already difficult task of identifying high impedance faults through conventional overcurrent protections. This study provides valuable insights into the integration of photovoltaic inverters into distribution systems, and can aid in the development of effective protection measures for future grid designs.

Application of Under-Impedance Criterion to Protect against Effects of Phase-to-Phase Short Circuits in Medium-Voltage Networks

Common overcurrent criteria used to detect phase-to-phase short circuits in medium-voltage (MV) networks in some cases do not bring the expected results. In particular, this applies to instantaneous overcurrent protections in lines with variable ranges and lines leading to local power plants (LPP), which generate a short-circuit current slightly greater than the rated current. When using overcurrent protections, there are some problems with ensuring the appropriate sensitivity and selectivity. This article proposes a protection based on impedance measurement against the effects of phase-to-phase short circuits in MV lines. The protection can be used at switchgears and also at protection points (PP) located deep in the network. The under-impedance criterion has a range independent of the value of the short-circuit current, and it can be alternative or complement to classic overcurrent protection. The introduction of these criteria allows the protection range to be independent of the type of short circuit and the short-circuit power on the busbar, and to determine this range more precisely. The under-impedance protection is particularly useful in conditions of a growing number of energy sources deep inside the networks and its automation. The main idea was to develop a uncomplicated characteristic that would ensure the possibility of setting the under-impedance protection by people who are not specialists in the field of distance protections. The characteristics have been optimally developed both in terms of the area of detected impedances and easy implementation, operation, and configuration.

Multi-Objective Optimal Allocation of Hybrid Photovoltaic Distributed Generators and Distribution Static Var Compensators in Radial Distribution Systems Using Various Optimization Algorithms

In recent years, considerable growth was about the integration of renewable energy sources in the Radial Distribution Systems (RDS), as Photovoltaic Distributed Generators (PVDG) due to their importance in achieving plenty desired technical and economic benefits. Implementation of the Distribution Static Var Compensator (DSVC) in addition to the PVDG would be one of the best choices that may provide the maximum of those benefits. Hence, it is crucial to determine the optimal allocation of the devices (PVDG and DSVC) into RDS to get satisfactory results and solutions. This paper is devoted to solve the allocation problem (locate and size) of hybrid PVDG and DSVC units into the standards test systems IEEE 33-bus and 69-bus RDSs. Solving the formulated problem of the optimal integration of hybrid PVDG and DSVC units is based on minimizing the proposed Multi-Objective Function (MOF) which is represented as the sum of the technical-economic parameters of Total Active Power Loss (TAPL), Total Reactive Power Loss (TRPL), Total Voltage Deviation (TVD), Total Operation Time (TOT) of the overcurrent relays (OCRs) installed in the RDS, the Investment Cost of PVDGs (ICPVDG) and the Investment Cost of DSVCs (ICDSVC), by applying various recent metaheuristic optimization algorithms. The simulation results reveal the superiority and the effectiveness of the Slime Mould Algorithm (SMA) in providing the minimum of MOF, including minimization of the power losses until 16.209 kW, and 12.11 kVar for the first RDS, 4.756 kW and 7.003 kVar for the second RDS, enhancing the voltage profiles and the overcurrent protection system. Moreover, the ability to reach the optimal allocation of PVDG and DSVC and maintain the voltage profiles in the allowable limit, whatever the load demand variation.

Voltage-Controlled and Current-Controlled Low Voltage STATCOM: A Comparison

Inverter-based converters interconnecting DC microgrids and AC-microgrids/grids are in a strong expansion. Besides power exchange, the inverter can be requested to furnish ancillary services and, among them, power factor compensation. This work presents a comparison between voltage control and current control in a low voltage inverter in a STATCOM operation. Both strategies use P&O controllers to control power factor, but in voltage-control the P&O adjust modulation index while in current-control P&O adjusts the current reference. HIL simulations show that both controllers can efficiently increase power factor; however, voltage control requires additional overcurrent protection. Current control can easily limit the devices current, but requires an extra current measurement when compared to the voltage controller, therefore has increased cost.

A Comprehensive Approach to Flexible LVRT Strategies for Inverter-Based PPMs Enhancing Voltage-Support, Overcurrent Protection, and DC-Link Voltage Quality

A Comprehensive Approach to Flexible LVRT Strategies for Inverter-Based PPMs Enhancing Voltage-Support, Overcurrent Protection, and DC-Link Voltage Quality

Analytical Modelling of Fault Transient in a GaN HEMT Half Bridge and its Overcurrent Protection with PCB Embedded Rogowski Coils

Analytical Modelling of Fault Transient in a GaN HEMT Half Bridge and its Overcurrent Protection with PCB Embedded Rogowski Coils

Adaptive Quasi-Power Differential Protection Scheme for Active Distribution Networks

With the massive integration of distributed generations (DGs), distribution networks gradually become more active and flexible. Conventional overcurrent protection is difficult to adapt to such active distribution networks (ADNs). Current differential protection (CDP) is a good choice for solving this issue, but the multi-branch structure of ADNs especially the unmeasured T-connected load branch affects the protection’s sensitivity. Therefore, the paper proposes a quasipower differential protection (QDP) scheme based on Tellegen’s theorem. First, the feasibility of applying Tellegen’s theorem to ADNs was analyzed. On this basis, reasonable protection criteria were designed for different scenarios of ADNs. Then, an adaptive protection scheme was established, which can automatically adjust the criteria depending on the presence of Tconnected branches within the protected section. Finally, extensive simulations were carried out in an ADN model using PSCAD/EMTDC software. The simulation results demonstrate that the proposed protection scheme has excellent adaptability to network topologies, fault types, fault resistances, and network structures of ADNs.

Assessment of an Overcurrent Protection Strategy Based on Thermal Stress Curves in Distribution Networks Under Reconfiguration Scenarios

Assessment of an Overcurrent Protection Strategy Based on Thermal Stress Curves in Distribution Networks Under Reconfiguration Scenarios

Review: Relay coordination in DGs with Electric Vehicle

This research offers a comprehensive examination of the most effective approach to synchronize overcurrent relays within a protective system alongside protective relay. Every effort has been made to encompass all potential strategies for achieving optimal coordination among overcurrent relays. Both modern approaches, like Harris hawk optimisation, and more traditional ones, such ground-based circuit breakers, are included in this category of overcurrent protection with Electric Vehicle. The operation of a Smart Grid [1] is characterized by varying load demands, generation levels from DGs, and charging/discharging behaviours of EVs. These factors can lead to different fault currents and altered fault impedance profiles at various times. An adaptive coordination scheme can dynamically adjust relay settings based on these changing conditions to optimize sensitivity and minimize coordination time. In this paper briefly discuss traditional approaches but focus mostly on using Harris Hawk Optimisation to enhance the coordination of overcurrent relays. This document compiles citations for all relevant works and offers a concise overview of the study conducted. Furthermore, the outcomes of these methods are documented in their corresponding references.

Adaptive harmonic-based protection coordination for inverter-dominated isolated microgrids considering N-1 contingency

Protection coordination is typically approached considering the main network configuration. Nevertheless, contingencies such as generator or line failures may disrupt power grids. Low fault currents in inverter-based isolated microgrids adversely impact the conventional overcurrent protection schemes. This paper proposes a sensitive and selective protection scheme for isolated microgrids using an adaptive third harmonic voltage generated by inverter-based distributed generators (IBDGs) and adapted to fault severity. The generated harmonic voltage results in a harmonic layer established during faults and is decoupled from the fundamental fault current, which is limited by IBDGs. Harmonic directional overcurrent relays sense the generated harmonic currents and voltages at the relay location to ensure optimal protection coordination (OPC). The OPC problem is formulated as a constrained nonlinear program to determine the optimal relays’ settings. The constraints are defined for the isolated configuration and each potential configuration resulting from an N-1 contingency. A radial microgrid that is part of a Canadian urban distribution network is used to ensure the successful operation of the proposed protection scheme. The results demonstrate the ability of the proposed scheme to protect isolated microgrids and preserve protection coordination without communication.