Performance Of Distance Relay Research Articles

Advancing Distance Relaying Reliability: S Transform Solution for Renewable Energy-Infused Smart Grid

Distance relaying is a crucial component in safeguarding transmission lines globally. However, the presence of Sub-Synchronous Resonance (SSR) introduces challenges, as oscillations in voltage and current magnitudes adversely affect the performance of conventional distance relays. Detecting faults accurately during these oscillations poses a significant challenge for traditional relaying mechanisms. This paper addresses the issue of SSR-induced maloperations in distance relays, particularly in the context of the increasing penetration of renewable energy resources in smart grids. The integration of wind power into the grid generates sub-synchronous oscillations, leading to protection issues. In response, a novel solution leveraging the S transform, a modern signal processing technique, is proposed to enhance the robustness of distance relaying under such challenging conditions. The developed algorithm is implemented in MATLAB and rigorously tested on the First Benchmark Model of sub-synchronous resonance. Simulation of the model is conducted in the PSCAD simulation software, and the results are thoroughly validated in MATLAB. The study demonstrates the efficacy of the S transform-based approach in accurately identifying faults and mitigating maloperations caused by SSR, thereby improving the reliability of distance relaying in smart grids with high renewable energy integration.

Statistical Design of Experiments for Power System Protection Testing: A Case Study for Distance Relay Performance Testing

Statistical Design of Experiments for Power System Protection Testing: A Case Study for Distance Relay Performance Testing

A new method for improving the fault detection performance of distance relays during power swings

A new method for improving the fault detection performance of distance relays during power swings

An enhanced sensitive power differential protection for series compensated transmission lines in renewable generation intensive power systems

Series compensation is widely used to improve the electrical characteristics of long transmission lines and increase the power transfer capability. However, the insertion of a series capacitor introduces various phenomena that affect the performance of traditional distance relays. Moreover, the fault characteristics of renewable generation systems coupled with generation outputs that vary with weather patterns produce additional complications to the protection of transmission lines. This paper proposes the application of an enhanced sensitive power differential protection (SPDP) algorithm to the protection of series compensated transmission lines. The algorithm incorporates a criterion that improves the security of the protection by inhibiting the SPDP algorithm from operating for faults external to the protected line. Performance of the enhanced SPDP algorithm has been evaluated on a test system built in Digsilent Powerfactory software. Various in-zone and out-of-zone fault cases were simulated at different compensation levels and fault resistances. The results showed that the enhanced SPDP protection technique can detect in-zone faults along practically the entire transmission line (99.99 %) for compensation levels up to 90 %. The method operated reliably for faults with resistances up to 330 Ω.

Performance enhancement of distance relay in presence of unified power flow controller

The characteristics of the distance relay are devised based on online and fault impedance. The relay uses fault information to react to the expected state; however, integrating the grid with a unified power flow controller (UPFC) might stop the relay from fault-triggered operations, requiring altered relay characteristics. Building relay tripping parameters are among the critical challenges that must be addressed for transmission line distance relays because current transmission networks face higher stress regarding power system operation. Furthermore, the use of flexible AC transmission systems (FACTS) instruments at the transmission level adversely affects distance relay performance due to impedance differences. The UPFC is among the essential FACTS instruments; it comprises shunt and series converters to alter the apparent relay impedance; hence, it was considered for this study, where a test system during fault was assessed to demonstrate the output of the distance relay before and after using the UPFC. MATLAB was used to build scenarios demonstrating the effect of a UPFC located in the transmission line's midsection or end or not using the UPFC. This research offers an analytical technique to determine the probable effects of UPFC on distance relay characteristics. The outcomes provide new relay characteristics for several fault resistances and locations for fault-specific impedance trajectory reactions.

Compensated fault impedance estimation for distance-based protection in active distribution networks

Electric distribution networks are experiencing fast changes mainly due to the integration of distributed energy resources. These changes originate the active distribution networks, where several distributed energy resources are integrated, usually using power converters. In these active networks, the conventional control, operation, and protection schemes used in power systems are unsuitable, and as a consequence, new approaches must be proposed and tested. This paper analyses the distance relay performance in active distribution networks; as the main contribution, a communication-less compensation strategy is proposed to deal with the effects of fault resistance and the distributed energy resources’ infeed and remote currents. The obtained results demonstrate the excellent performance of the proposed compensation strategy aimed at determining the true value of the estimated positive sequence impedance. This compensation can be easily integrated into the software of conventional distance relays to overcome fault resistance, infeed, and remote current effects.

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%).

Improving distance relay performance for heavily distorted voltage and current by accurate signal reconstruction using extended Kalman filter

Distance relay plays a pivotal role in the detection of faults and subsequent isolation in transmission lines. However, severe distortion in the measured voltage and current waveforms (such as due to current transformer (CT) saturation), affects their performance. This paper focuses on a compensation method for signal reconstruction using extended Kalman filter (EKF) algorithm to improve relay functioning, enhancing the safety of transmission lines. The proposed fault detection scheme was tested extensively by running simulations using PSCAD and MATLAB for different types of faults at various distances and CT burden. The CT model in PSCAD was developed based on the Jiles–Atherton phenomenological theory in order to closely resemble a real-time CT with its saturation effects. The simulation results show that the proposed method is highly efficient in determining the exact fault point with improved zone approaching times even with measured signals having high noise and harmonic content. In cases where the conventional relay fails to detect the fault in the correct zone, the compensated data from the proposed method accurately detects the zone. Hardware experimental tests were carried out to further verify the effectiveness of the scheme in real-time, where the EKF based algorithm was implemented using a DSP-based microcontroller.

Enhancing distance relay performance using wide-area protection for detecting symmetrical/unsymmetrical faults during power swings

The distance protection in transmission networks is vulnerable to malfunction during a power swing. Distance relays have a power swing blocking (PSB) function that prevents the relay from operating during a power swing. However, during a power swing, the relay will be able to identify and clear any fault. This paper offers a scheme for detecting symmetrical/unsymmetrical faults through power swing by estimating the maximum rate of change of a (ΔI-ΔV) ellipse circumference. The ellipse circumference of each phase is constructed at each power frequency cycle to consistently tracking the distinction in the measured current and voltage differences between the line's two ends. The main feature of the suggested work compared to previous works is the ability to detect numerous high impedance faults (HIFs) during single mode (slow/fast) power swing or multi-mode power swing in addition to the opportunity to detect faults during asymmetrical power swing. The suggested scheme is tested in a two-area, four-machine power system and tested also in the standard three-machine, nine-bus system using ATP software. The results reveal that the improved protective scheme performs well in fault conditions with and without power swing, and they confirm the scheme's suitability for interconnected networks.

A new adaptive coordination scheme of distance relays in DFIG ‐ based wind farm collector lines and transmission line compensated by STATCOM

This paper proposes an adaptive characteristic for eliminating the adverse effects of fault resistance and static synchronous compensator (STATCOM) on the performance of distance relays in transmission line and collector lines of doubly-fed induction generator (DFIG)-based wind farms in the case of single-phase-to-ground resistive faults. The proposed method improves the performance in distance relaying and maintains the coordination between relay pairs in the transmission line and wind farm collector lines. In this method, an adaptive coefficient that can modify the zone settings of conventional distance relays is added to their characteristic to improve the accuracy and coordination under the mentioned conditions. Using analytical relationships and numerical results from simulations in Matlab/Simulink environment, the efficiency of the proposed method is confirmed.

An accurate technique for supervising distance relays during power swing

Power swing is a power system transient phenomenon that arises due to several reasons including line switching, line outage, sudden increment or decrement in load, faults, etc. Unnecessary tripping during power swing and unnecessary blocking for faults occur during power swing result in distance relay maloperation. Several cascaded outages and major worldwide blackouts have occurred due to maloperation of distance relays. This paper proposes a technique for supervising distance relays during power swing. The proposed online technique discriminates real faults and power swing accurately. It relies on constructing a locus diagram for the current and voltage differences (∆I-∆V) between the two ends of the protected line. The locus is estimated at every power frequency cycle to continuously monitor the state of the line by utilizing the synchrophasor measurements at the sending and receiving ends of the line. The proposed technique is tested for two-area, four-machine power system under faults at different locations of zone-1 and zone-2 regions of distance relays, fault resistances, fault inception angles and slip frequencies using MATLAB software. The simulation results proved the superior improvement of distance relay performance for handling power swing blocking and unblocking actions.

Impact of STATCOM and BFCL on the performance of distance relay and its improvement by adaptive setting for grid‐interactive offshore wind and marine current farm

This study explores the impact of the dynamic impedance of static synchronous compensator (STATCOM) and bridge type fault current limiter (BFCL) on the performance of distance relay and its improvement by adaptive setting for Grid Interactive Offshore Wind and Marine-Current Farm. For assessments, analytical results are presented under different STATCOM settings, low voltage ride through (LVRT) condition, and different types of fault conditions. Moreover, the presence of STATCOM and BFCL significantly changes the apparent impedance characteristic of the studied system. It is also seen that the presence of STATCOM likely to induce an under reach and overreach problem of distance relay. Further, the LVRT capability is significantly affected as STATCOM supplies reactive power to offshore wind generators during a short circuit on the grid side. It is found that the grid integration of OWF and MCF with STATCOM and BFCL is likely to induce mis-coordination and subsequently deteriorate the performance of distance relay, leading to system security problems. Therefore, this study proposed an adaptive setting in order to eliminate the simultaneous influence upon the dynamic impedance due to incorporation of STATCOM and BFCL on the distance relay setting. The simulation results show the efficacy of the proposed adaptive setting.

A New Approach for Protecting TCSC Compensated Transmission Lines Connected to DFIG-Based Wind Farm

Thyristor-controlled series capacitor (TCSC) compensated transmission lines (TLs) are increasingly used in recent years for transmission of bulk power generated by doubly fed induction generator (DFIG) based large scale wind farms. However, the typical fault characteristics of DFIG and TCSC affect the performance of conventional distance relays. To solve the problem, in this article, a new relaying algorithm is proposed that utilizes sign of the half-cycle superimposed positive-sequence current for fault detection, empirical mode decomposition assisted random forest classifier for fault classification and modified impedance approach for fault location estimation. The performance of the proposed relaying algorithm is evaluated on various fault and nonfault cases generated on a test power system using MATLAB/Simulink and OPAL-RT (OP4510) manufactured real-time digital simulator environment. Also, compared with few existing approaches. The demonstrated results justify the merits of the proposed relaying algorithm for protecting the TCSC compensated TL connected with DFIG-based wind farm.

Studi Pemanfaatan Relai Jarak Quadrilateral untuk Proteksi Saluran Distribusi dengan Pembangkit Tersebar

Installation of distributed generations (DGs) in distribution network bring benefits for power system operation. However, DGs change the distribution network topologies from radial with one source into multi-sources network, hence magnitude and direction of the current will also change. Consequently, the existing distribution line protection i.e. current based protection, experience performances deterioration. To overcome this problem, distance relays, which work based on calculated impedance is proposed. However, since mho distance relays fail to detect faults through resistance in previous research, quadrilateral characteristic of distance relay is chosen. Quadrilateral distance relays have separate setting for reach and resistance; hence it is expected it will accommodate fault resistance. Therefore, this research aims to identify the performance of quadrilateral distance relay in protecting distribution lines that having DG. The research method is computer simulation where quadrilateral distance relays performance is tested for various faults and system conditions in a test system. The software for the simulation is Digsilent Power factory. The results conclude that the quadrilateral distance relays experienced failures to detect faults in correct zone operation due to a weak source of DG. DG generates less fault current, as consequences, the relays see large impedances.

An improved numerical distance relay based on CCVT transient characteristic matching

The transients of the coupling capacitor voltage transformer (CCVT) have an impact on the performance of distance relays and result in the overreach problem. Based on the equal transfer process of transmission lines (ETPTL) theory, the virtual digital CCVT can be applied to reduce the impact of the CCVT transients and improve the operation speed of distance relays. The virtual digital CCVT is required to have the same transient characteristics as the actual CCVT. This paper proposes a simple and universal design method of virtual digital CCVT. Based on the CCVT transient characteristic matching and the ETPTL theory, this paper proposes an improved numerical distance relay algorithm to prevent the overreach problem of distance relays without sacrificing the operation speed of distance relay under the internal fault conditions. An extensive performance evaluation using PSCAD/EMTDC simulation corroborates the effectiveness of the proposed distance relay under different fault conditions. Finally, a prototype device based on the proposed distance relay is developed in laboratory and evaluated through a hardware in loop test using real-time digital simulator (RTDS).

Adaptive Protection of Partially Coupled Transmission Lines

The mutual coupling effect in parallel transmission lines renders the maloperation of conventional distance relays and makes it more difficult for power system operators to establish a reliable operation of transmission systems. This paper presents an adaptive protection system approach to improve the performance of conventional distance relays in partially coupled transmission lines. The conducted study deals with single-line-to-ground faults and the proposed algorithm is designed for ground distance units. The mutually coupled transmission lines, which are not terminated in same substations, are studied and the impedance estimated by associated distance relays is corrected through revising the level of zero sequence compensation. The compensation term is calculated based on the system equivalent sequential networks and it is substituted in an iterative process for enhancing its accuracy. The proposed approach can offset the fault resistance effect to calculate an accurate fault impedance. The proposed approach lies in the local protection category and utilizes local and very limited remote data for decision making. Simulation results present the adaptive features of the proposed protection scheme. Besides, practical applications of the proposed approach are demonstrated and analyzed through experimental studies by developing a prototype on a MCU (LPC2368_ARM7TDMI) processor.

A Fault Detection and Classification Scheme for Unified Power Flow Controller Compensated Transmission Lines Connecting Wind Farms

In recent years, there is an increasing trend of integrating large capacity offshore wind farms into power grids through UPFC compensated TLs for accommodating large flow of power. The nonlinear fluctuations of output power due to unpredictable variation of wind speed and the different operating modes of the UPFC greatly affect the performance of the conventional distance relaying-based TL protection scheme. This article investigates the impact of such TLs on distance relay performance and proposes a two criteria-based new fault detection and classification scheme. The method utilizes the sign of the change in the magnitude of positive-sequence current at both ends of the line for fault detection and the transient monitor index derived from the locally measured three-phase current for fault classification. The performance of the proposed scheme is evaluated on different fault and nonfault transients generated on two standard test systems through EMTDC/PSCAD during different operating modes of UPFC and at different wind speed. The performance of the proposed scheme is further validated through dSPACE DS 1103-based real-time digital simulation platform. Finally, the comparative assessment results with some important existing methods justify the effectiveness of the proposed method.

Adaptive Distance Protection for Transmission Lines Incorporating SSSC With Energy Storage Device

A Static Synchronous Series Compensator incorporating energy storage device (SSSC-ES) at the DC bus enables the exchange of true power with the system in addition to line reactance compensation. This facilitates improved control of real and reactive power in a transmission system. However, the four-quadrant operation of SSSC presents additional problems for the accurate operation of conventional transmission line protection. In this paper, an in-depth analysis of the effect of emulated reactance and resistance by SSSC-ES installed at the center of a hybrid series compensated line on the performance of distance relay is carried out. An investigation is performed with all possible operating modes and control strategies of SSSC-ES, and the possibility of mal-operation of distance protection are explored. A novel adaptive setting based on constant reactance and constant resistance emulation control strategy of SSSC is proposed for quadrilateral distance relay to prevent the mal-operation. MATLAB / SIMULINK is used for the simulation study.

Comprehensive Analysis of the Impact of the TCSC on Distance Relays in Interconnected Transmission Networks

This article extensively investigates the calculations of the compensation factor of the thyristor-controlled series compensator (TCSC), which are used to accurately evaluate the negative impacts of the TCSC on the performance of conventional distance relays. To broadly evaluate the distance protection performance, the TCSC was adapted to the IEEE 9-bus system as one of the interconnected transmission networks that are increasingly spreading to improve service reliability, reduce reserve capacity, and enhance system efficiency. In addition, IEEE 39-bus system, as a large interconnected system, is also examined to generalize the TCSC impact on different interconnected systems. To determine the precise impact, the impedance of the TCSC was calculated based on its practical design parameters. The impedance of the TCSC was examined as a function of transmission line impedance and firing angle. Both Mho and Quadrilateral distance relays were tested using the MATLAB/Simulink environment for different types of faults, fault locations, fault resistances, and firing angles for capacitive, inductive, and blocking modes of TCSC operation. In addition, distance relay performance was evaluated during power swing phenomenon in the presence of the TCSC. Simulation tests indicated the negative impacts of the TCSC on distance relay operation, which are not limited to over-reach and under-reach in faulty conditions but also to maloperation in dynamic disturbances that cause power swing phenomena on the protected line.

The Impact of STATCOM on Power Systems Protection Devices

This paper introduces the impact of installing FACTS devices on protection systems. STATCOM is used to indicate its impact on distance relay. To check the feasibility installing of STATCOM into power system for improving the distance relay performance, the zones are suggested (Z1, Z2 and Z3) and have been calculated in order to improve the performance of distance relay protection and to prevent circuit breaker disturbance tripping. The simulation results are carried out in MATLAB software. The results reveal that the apparent impedance doesn’t change when the distance relay is tested without STATCOM device under different locations of faults. After installing STATCOM in transmission line, the apparent impedance doesn’t change and it equals the actual impedance in spite of compensation modes of STATCOM