Distance Protection Relays Research Articles

An adaptive distance protection scheme considering fault resistance, injected current, and structural changes in the power system

AbstractFaults in power systems occur for various reasons, such as aging or natural disasters. Detecting, locating, and promptly clearing these faults is crucial for maintaining the safety and reliability of transmission lines (TLs). Distance relays (DRs), which protect TLs, detect faults, estimate their location, and send the required commands. However, these relays may experience mis‐detection due to manipulated impedance arising from both internal and external factors. These factors include measurement device errors, network topology changes, the presence of fault resistance (FR), and injected currents from remote line terminals. To address this challenge, an innovative adaptive protection scheme that considers FR, changes in network topology, and injected current from the opposite end of the line is proposed. By estimating the equivalent circuit impedances (ECIs) of the network connected to the terminal of the TL, this protection scheme utilizes impedance estimation techniques at the line terminals and offline network information. Simulation studies (tested on the IEEE 39‐bus standard network) show that the proposed scheme accurately estimates fault location (FL) and FR with high precision. The simulation results demonstrate its effectiveness in improving the performance of conventional distance protection relays in both the first and second protection zones ( and ).

مرحل حماية المسافة وتأثير MOV على مناطق المرحل بإستخدام الماتلاب

Transmission lines are an important part of the power system. Transmission lines are used to transmit power and are prone to many breakdowns. Therefore, protection relays are used to protect transmission lines. The purpose of the protection system is to isolate the faulty part from the healthy part, because large currents generated by faults may cause damage to electrical equipment. One of the protection relays is the distance relay and is mainly used in the transmission line. Sometimes these relays are used for backup protection. Distance relays to determine impedance need voltage and current. Transmission lines are usually protected by a distance protection relay. Distance relays are of the high-speed class and can provide transmission lines. Protection distance relays that use impedance measurements to determine the presence and location of faults, are "fooled" by a series capacitor mounted on the line, when the presence or absence of a capacitor in the fault circuit is not known in advance. This is because the capacitor cancels or compensates for some of the line inductance, so the relay may sense a fault in its first region when the fault is actually in the second or third region of the protection. Similarly, Zone one fault can be considered reverse faults. In fact, this can cause some costly operating errors. Series compensated lines are protected from overvoltage by metal-oxide-varistors (MOVs) connected in parallel with the capacitor bank. The nonlinear characteristics of MOV devices add complexity to fault analysis and distance protection operation. During faults, the impedance of the line is modified by an equivalent impedance of the parallel MOV/capacitor circuit. Worth noting is a method that determines the L and C string values of the font and the MOV effect at the time of the error. This is done by analyzing the synchronous and sub-synchronous content of the voltage and current signals separately which provides enough information to calculate the L and C series of the line. In this paper, the transmission line impedance Z, Z(f) as a function of frequency has been calculated and plotted by the sequence characteristics and the studied MOV effect on line protection and fault location. Proper operation of the distance protection relay is also shown, and its effect on relay regions. Keywords: Distance protection relay, transmission line, zones of relay, MOV.

Real-Time Co-Simulation for the Analysis of Cyber Attacks Impact on Distance Relay Backup Protection

Smart Grid is a cyber-physical system that incorporates Information and Communication Technologies (ICT) into the physical power system, which introduces vulnerabilities to the grid and opens the door to cyber attacks. Wide area protection is one of the most important smart grid applications that aims at protecting the power system against faults and disturbances, which makes it an attractive target to cyber attacks, aiming at compromising the reliability of the power system. Understanding the interaction between the cyber and physical components of the smart grid and analyzing the damage that cyber-attacks can do to wide area protection is very important as it helps in developing effective mitigation approaches. This paper evaluates the impact of cyber attacks on a wide area distance relay backup protection scheme in real-time, through the development of a co-simulation platform based on Real Time Digital Simulator (RTDS) and network simulator 3 (NS3) and using the IEEE-14 bus power system model.

Improving power swing detection in the presence of doubly-fed induction generator wind farms based on setting adaptation

This article proposes a new approach to improve the security of transmission line protection by correctly detecting power swing when large-scale doubly-fed induction generator wind farms (DFIGWF) exist in the proximity of the relay. In the presence of large-scale DFIGWFs, following large disturbances, power swing may probably cause the distance protection to malfunction. This issue can also lead to widespread transmission line outage and cause instability in the power system. Therefore, a new approach is proposed to solve the challenge by adapting the power swing blocking (PSB) function in the distance protection relays and utilizing the dominant power system oscillation modes. Thus, related calculations are performed in a central module remotely connected to intelligent electronic devices (IEDs) for distance protection and stabilized against power swing. The calculation to adjust the PSB setting of the IEDs in the central module is based on the oscillation modes of the power system and the rate of change of impedance, which is influenced by the penetration rate of the DFIGWFs. Simulation studies have been done on two test systems and the results reveal that the proposed scheme significantly improves the security of distance protection against power swing under different DFIGWF intrusion conditions.

Decision Tree Models and Machine Learning Algorithms in the Fault Recognition on Power Lines with Branches

The complication of the structure, topology and composition of the future electrical networks is characterized by difficult-to-recognize circuit-mode situations and requires modern methods for analyzing information parameters. The growing trend of digitizing signals in substations and the use of the IEC 61850 standard results in a huge amount of new data available at the nodes of the electrical network. The development and analysis of new methods for detecting and recognizing the modes of electrical networks (normal and emergency) are topical research issues. The article explores a new approach to recognizing a faulted section of an electrical network with branches by concurrently analyzing several information features and applying machine learning methods: decision tree, random forest, and gradient boosting. The application of this approach for decision-making by relay protection has not been previously implemented. Simulation modeling and the Monte Carlo method are at the heart of obtaining training samples. The results of testing the studied methods under review showed the required flexibility, the ability to use a large number of information parameters, as well as the best results of fault recognition in comparison with the distance protection relay.

Effect of Electric Vehicle Charging Stations on the Performance of Distance Relay

Distance protection is considered important and essential in power systems. Due to the development of distribution systems and the system's topology change from time to time, integrating electric vehicles into the distribution system leads to an increase in short circuit level and injection of harmonics into the system. Since the vehicles are continuously variable loads, this leads to difficulty in adjusting the protections that depend on the current in the process of adjusting them. As a result, distance protection is used in distribution systems. This paper shows the effect of integrating electric vehicle charging stations on the relay performance of distance protection in the distribution system. Distance protection relay was built based on artificial neural networks adapted to the system conditions. The accuracy of the neural network model used for fault detection was (99.9%), and the error rate in locating the fault was (0.00079%).

Kajian Koordinasi Sistem Proteksi Pada Sistem Transmisi 70 kV GI Banaran Kediri Transmission Line Bay Pare

The substation is one of the components in the electric power distribution system which plays a very important role because itis the connection between electricity services to customers. In the electric power distribution system, there are disturbances that often occur,one of which is a short circuit. For that, the way to overcome this is using the Distance Relay protection system, OCR / GFR and DEF. Thepurpose of writing this research is to determine the value of setting relay distance, setting Over Current Rele and Directional Earth Fault relayin order to secure the 70 kV transmission network connected to GI Banaran, which is then simulated using DigSILENT 15.1 software on thePare line by calculating symmetrical and asymmetrical disturbances. including 3-phase disturbance on February 1, 2018. The simulationresults show that the 3-phase disturbance occurs at Zone 1 relay distance of the Banaran Bay Pare substation with a trip time of 0.02 secondswith a fault impedance of 0.083 ohms below the relay impedance value of 0.887 ohms. The coordination between the distance relay on theside of the Banaran Bay Pare substation has worked well because there is no error reading the relay when it will cut off the disturbance.

Protection Algorithms for Closed-Ring Grids With Distributed Generation

This paper proposes an approach to mitigate adverse effects of the fault management of closed/ring grids with high shares of distributed generation (DG). The approach refers to conventional distance protection relays in particular. The rising share of DG, especially in distribution systems, can lead to overloadings and intolerable voltages. Closed-ring structures increase the grid capacity for DG due to more balanced load and voltages profiles. However, malfunctions of protection relays may occur because fault locating and selective fault clearing can be disturbed. This paper presents a distance protection algorithm for feeder relays that complies with the requirements of closed/ring grids with inter/infeeds. The proposed current comparison method (CCM) bases on the comparison of negative/sequence currents. It needs no voltage measurement and remains unaffected from inter/infeeds and fault resistances. Additionally, for relays located at the ring coupler, where the ring can be opened, a coupling relay method (CRM) is proposed. It locates unsymmetrical faults in closed/ring grids with inter/infeeds and enables fast and selective opening of the ring. This helps maintaining reliable power supply for customers in closed rings. Finally, the paper presents a grading strategy reducing the average fault clearing time. Lab tests prove the capability of both proposed algorithms.

Analysis of the Impact of a Modular SSSC on the Operation of Transmission Line Protection Relays using a Hardware-In-the-Loop Configuration

This paper evaluates the impact of a modular Static Synchronous Series Compensator (m-SSSC) on the operation of communication-assisted line distance and differential protection relays. The m-SSSC system incorporates an over-current protection feature to trigger the bypass mode of operation during grid faults. A case study is analyzed for a 220 kV transmission line and an m-SSSC with a reactive power rating of 80 MVAr per phase using a Hardware-In-the-Loop configuration. The obtained results show the impact of the m-SSSC system on the distance protection operation during some cases of high resistive faults. The differential protection operation was not affected by the mSSSC.

An adaptive time–frequency approach based secured back-up distance protection scheme for system stress conditions

Critical operating conditions of power system may lead to distance relay security issues. Distance relay back-up protection is offered with long reach setting and due to this under sudden change in voltage and current parameters during non-fault situations also considered as a fault by the protection function in an integrated network. The conventional technique fails to discriminate system stress conditions such as power swing, voltage instability and load encroachment from an actual symmetrical fault in the back-up zone (third zone (Z3)) of the distance relay. To mitigate this, a Modified Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (MCEEMDAN) technique is used to decompose the instantaneous power and to develop a reliable index. The most significant intrinsic mode function (IMFs) is extracted to estimate the energy as used as detection index. An adaptive statistical threshold selection process is developed to detect and discriminate all system stress conditions from symmetrical fault in the back-up zone of the distance relay. The proposed algorithm is a supervisory scheme for the back-up zone setting (Z3) of the distance relay. Simulation results for different stress conditions, presence of noise, sudden switching of load and symmetrical fault are presented to highlight the strength of the method.

A Straightforward Power Swing Detection Algorithm Using Rate of Impedance Angle Change

Mal-operation of distance protection relays during power swing (PS) condition can endanger the power system stability. Therefore, it is crucial to distinguish between short-circuit faults and PS by a power swing blocking (PSB) function to prevent undesired tripping of distance relay. This paper develops a novel and straightforward PSB method based on the rate of impedance angle change (RIAC). Not only can the proposed approach fairly discriminate both symmetrical and asymmetrical faults from PS, but also it can appropriately preserve protection scheme security during PS under single-pole tripping (SPT) on a transmission line. Furthermore, there is no need to perform extensive dynamic stability studies for setting the PSB function parameters. Unlike the rate of impedance change approaches utilized two blinders, the developed approach only needs an inner blinder. Thus, it can be used for networks running near their operational limits. The proposed method is evaluated through a modified IEEE-PSRC benchmark system in PSCAD/EMTC environment. The obtained results verify superior performance of the proposed method to traditional impedance rate of change method under different scenarios.

An innovative method to eliminate multiple exponentially decaying DC components based on the discrete Fourier transform in the numerical distance relay

Exponentially decaying direct current (EDDC) components in the faulted current of a power system can result in an imprecise estimation of the fundamental frequency component. Because of sources such as the faulted transmission line, the current transformer (CT), and the relay's internal CT, current signals tend to include multiple EDDC components. This paper presents an accurate model of the faulted current, including a new term of EDDC components that belongs to the relay's internal CT along with the transmission line and the CT response. Moreover, this paper proposes an innovative algorithm to eliminate multiple EDDC components. The feasibility and performance of the proposed algorithm were validated using several static, dynamic, and experimental tests. The static test was carried out using MathWorks’ MATLAB® software. For dynamic validation, the transient data of a power system (simulated in the commercial PSCAD© software) were employed to test the performance of the propounded method. The experimental test was performed on a distance protective relay manufactured by VEBKO AMIRKABIR Co. The main advantages of this method include the practical feasibility resulting from its simple structure, the ability to effectively suppress the adverse influence of multiple EDDC components (including the response of the transmission line, the CT, and the relay's internal CT), and the accuracy in estimating the fundamental frequency component.

Performance analysis of static var compensators for distance protection of Nigerian 132-kV sub-transmission network using Matlab/ Simulink model

In this paper, the influence of the Static Var Compensators (SVC) on distance relay protection when connected to the sub-transmission network of the Nigerian 132-kV grid system is investigated. This is carried out by monitoring the error margin of the fault locator associated with the distance protective relays when SVC is connected to the transmission line. The location of the SVC is selected such that there is a common primary source of power to the sub-transmission network (Ikorodu-Sagamu 132-kV transmission line) and the SVC, which is a shunt-connected device located on Ikorodu 132-kV bus. The fault is simulated at 33.6 km and 60.4 km respectively from the Ikorodu 132-kV sub-station in Matlab/ Simulink model and the simulation results obtained are used to investigate the influence of SVC on distance protective relay when connected to the 132-kV power transmission line. The results of the line faults are obtained with respect to earth for both zones one (1) and two (2) when SVC is connected and disconnected for all shunt type of faults. Thus, indicating under-reach and over-reach characteristics of the distance relay, when the SVC is connected and disconnected, while the transmission line protection showed no under-reach or over-reach characteristics for line-to-line fault for both zones with the SVC connected or disconnected. The results of this study show that though SVCs improve the quality of power to consumers, there is a tendency for under-reach and over-reach characteristics of the protective relay to be displayed when the relays are disconnected and connected, which introduces error margins to the fault locator in distance protective relays. Therefore, more detailed dynamic simulations are recommended for reducing the error margin.

Evaluation of HVDC system's impact and quantification of synchronous compensation for distance protection

This paper presents a comprehensive evaluation of the HVDC system's impact on distance protection via systematic and realistic experimental tests, along with theoretical analysis of the root causes of the identified compromised protection performance. A methodology for quantifying the impact of Synchronous Compensation (SC) in supporting the distance protection operation is also established. In this work, the performance of two widely used physical distance protection relays have been evaluated using a realistic Hardware'In'the'Loop (HIL) testing environment, where a total of 480 cases have been tested under a wide range of system scenarios. Representative cases with compromised protection performance are selected, where issues of under/over'reach, faulted phase selection and impedance measurement are identified and analysed. Furthermore, a method for quantifying the required SC level to address the under/over'reach issues resulting from HVDC systems is presented. The method establishes the relationship between the angle difference of the two'end fault current infeeds of the protected line and the SC level. Based on this relationship, the required SC capacity to constrain the angle difference within a targeted limit can be estimated, which offers a useful tool for system operators to appropriately size the SC's capacity with additional valuable insights from the distance protection perspective.

Rate of Change of Active Power as a Power Swing Blocking Function of Distance Relays

Power swings may cause undesired trips of protection relays and, consequently, shutting down power utility equipment, leading to the outage of loads. This paper presents a procedure for detecting power swings based on the rate of change of active power. When a power swing occurs, the derivative of the active power can be modeled as a sinusoidal function and, therefore, it is possible to estimate the frequency oscillation. The proposal takes advantage to this theoretical concept to detect power swings on transmission systems. Simulation results show that the developed algorithm has good performance, including research scenarios against low and large power swings. The protection relay is unblocked upon the occurence of a short-circuit. The proposed technique is simple to implement and can be employed as a Power Swing Blocking (PSB) function to avoid misoperation of distance protection relays.

COORDINACIÓN ADAPTATIVA DE LA PROTECCIÓN DE DISTANCIA SOBRE LÍNEAS DE SUBTRANSMISIÓN CONSIDERANDO LA INCORPORACIÓN DEL EFECTO PRODUCIDO POR LA GENERACIÓN ADYACENTE

ABSTRACT: This article describes an algorithm for an adaptive distance protection in a sub-transmission system considering operating conditions with changes in the topology due to an abnormal condition, electrical failure or a natural disaster, includes the effect of adjacent generation in the distance relay protection zones, with the incorporation of renewable energies in mixed participation. Two scenarios are proposed, in the first case occurred a contingency, and the transmission systems changes the initial topology. Protections are automatically reparametrized. The second case includes the income of renewable energy generation in a specific point of power electrical Systems. Protections are automatically recalculated. The objective of an automatic coordination permit to operator to restore the sensitivity, selectivity and reliability the electrical protection system in the lowest time. Keywords: Adaptive distance relay, renewable energy, distance protection, infeed effect..)

Considering Fault Resistance Influence on the Performance of Distance Protection Relay for a Proposed Optimal Algorithm with Using Statcom

Considering Fault Resistance Influence on the Performance of Distance Protection Relay for a Proposed Optimal Algorithm with Using Statcom

LSTM-Based Fault Direction Estimation and Protection Coordination for Networked Distribution System

While the world’s power distribution system resembles an intricate web-like structure, the most conventionally implemented distribution mechanism is the radial distribution system (RDS) where connection points for each distribution line are normally kept open. However, disadvantages regarding the traditional system have led to active research on establishing the networked distribution system (NDS), in which multiple circuits are interconnected with electricity as well as high-speed communication systems. The NDS offers multiple advantages including increased facility utilization, increased hosting capacity, and higher terminal voltage. Conversely, an unsolved issue prevails as the existing protection coordination method designed for the RDS is inadequate for fault occurrences in the NDS due to inaccurate fault direction identification. Hence, there is an urgent need for an alternative protection coordination method that allows high precision fault direction identification through communication. Moreover, the application of various existing technologies is hindered as the distance relay protection coordination algorithm malfunctions in situations where distribution lines are of short length, loads are dispersed onto multiple lines, and integration of distributed generation (DG) is frequent. Therefore, this paper presents a fault direction identification method that uses the waveform of the fault current based on long short-term memory (LSTM) neural network and a communication-based protection coordination scheme that can be applied in fault situations within an NDS.

Intrinsic time decomposition based differential protection with adaptive threshold for UPFC compensated transmission line

Abstract In the presence of nonlinear response created by power electronics-based compensators, reliable fault detection and classification by distance protection relays is a major concern. The unified power flow controller (UPFC) has a dynamic characteristics that causes stability and protection issues. A intrinsic time decomposition (ITD) based strategy is proposed for addressing this issue. A differential energy based detection index computed using ITD and adaptive thresholding technique is employed such that unerring fault detection is achieved wherein faulty phases of a UPFC compensated transmission line are well pointed out. Various fault and non-fault cases considering critical power system conditions are analysed for power systems with varying configurations modelled using EMTDC/PSCAD. A comparison of the current detection method to recently proposed techniques reveals the benefits and feasibility of the presented detection strategy, which has been proved to be accurate and efficient.

Taylor series based protection starting element for STATCOM compensated transmission line

• Non-unit protection of STATCOM-compensated lines irrespective of compensation mode and level. • Taylor series based detection index using current signal to detect faults. • Accurate identification and discrimination of fault and non-fault events. • Adaptive threshold technique immune to power system structure. • The executional burden time is near about 5 ms. In the presence of nonlinear response created by power electronics-based compensators, reliable fault detection and classification by distance protection relays is a major concern. The static synchronous compensator (STATCOM) has dynamic characteristics that causes stability and protection issues. A Taylor Series-based strategy is proposed for addressing this issue. A detection index computed using Taylor Series and adaptive thresholding technique is employed such that unerring fault detection is achieved wherein faulty phases of a shunt compensated transmission line are well pointed out. Various fault and non-fault cases considering critical power system conditions are analysed for power systems with varying configurations modelled using EMTDC/PSCAD. A comparison of the current detection method to recently proposed techniques reveals the benefits and feasibility of the presented detection strategy, which has been proved to be accurate and efficient.