Relay Protection Research Articles

Negative-sequence current filter based on inductance coils

The construction of new relay protection systems without the use of current transformers is a fundamental problem of electro energetics, which has not yet been solved. This works suggests a negative-sequence current filter which receives information from inductance coils (ICs) mounted at a safe distance in the magnetic field of phase currents. This filter does not require current transformers, thus saving high-quality copper, steel, and expensive high-voltage insulation in amount unprecedented for relay protection (a 6 to 110 kV current transformer has 19 to 480 kg in weight). A circuit (including functional diagnostics) and a technique for selecting the parameters of filter components and the points where ICs should be fixed are presented; a structure for IC fastening is described. Computer simulation and experiment were used for data collection. The data show that i) the filter conversion coefficient m= 1.6, and imbalance increases by 7% at the network frequency f= 48–52 Hz; ii) protections based on this filter should have a time delay; iii) the filter is not inferior to well-known well-tested filters with current transformers; and iv) it is functional, but can only be used for single-standing electrical installations.

A Modelling of 500 Kv Long Transmission Line and Fault Detection Using Inverse Definite Minimum Time Over Current (IDMT O/C) relay

As electricity demand increases day by day due to economic growth, the process of transmitting efficient electrical power is vital. Thus, a power simulation study is required to determine the mechanism of the transmission line, and possible faults that occurred in the transmission line system. On a daily basis, single line to ground fault (L-G), double line to ground fault (2L-G), and triple line to ground fault (3L-G) are the faults that normally occur in the long transmission line system. In this project, a model of a 300km/500 kV EHV transmission line consisting of a three-phase source, distribution line, and load is simulated using MATLAB software. When the L – G fault is applied, the voltage is diminished to zero and upon fault clearance, the R – G line produced overvoltage and overcurrent by 518.9 kV and 1889 A, which increased about 46.83% and 15.67% compared to normal lines of Y – G and B – G at 353. kV and 1633 A. Then, for the 2L – G fault, again the voltage is reduced to zero and when fault clearance occurred, the R – G and Y – G lines experienced overvoltage and overcurrent at 570.4 kV and 708.5kV, which showed more than 60% transient compared to normal line B-G at 353.4 kV. In Contrast, the 3L – G fault causes all transmission lines to experience overvoltage and overcurrent at different times and can damage the whole transmission system. Thus, to reduce the severe impact of fault, the Inverse Definite Minimum Time Over Current (IDMT O/C) relay protection is installed in the line model.

Recognition of Electrical Quantities in Measurements from Various Digital Relay Protection and Automation Devices

Recognition of Electrical Quantities in Measurements from Various Digital Relay Protection and Automation Devices

Optimal synchronization of overcurrent relays in active distribution networks using a hybrid genetic-differential optimization algorithm

Optimal synchronization of overcurrent relays in active distribution networks using a hybrid genetic-differential optimization algorithm

Modeling of Measuring Transducers for Relay Protection Systems of Electrical Installations.

The process of establishing relay protection and automation (RPA) settings for electric power systems (EPSs) entails complex calculations of operating modes. Traditionally, these calculations are based on symmetrical components, which require the building of equivalent circuits of various sequences. This approach can lead to errors both when identifying the operating modes and when modeling the RPA devices. Proper modeling of measuring transformers (MTs), symmetrical component filters (SCFs), and circuits connected to them effectively solves this problem, enabling the configuration of relay protection and automation systems. The methods of modeling the EPS in phase coordinates are proposed to simultaneously determine the operating modes of high-voltage networks and secondary circuits connected to the current and voltage transformers. The MT and SCF models are developed to concurrently identify the operating modes of secondary wiring circuits and calculate the power flow in the controlled EPS segments. This method is effective in addressing practical problems related to the configuration of the relay protection and automation systems. It can also be used when establishing cyber-physical power systems. For a comprehensive check of the adequacy of the MT models, 140 modes of the electric power system were determined which corresponded to time-varying traction loads. Based on the results of calculating the complexes of currents and voltages at the MT terminals, parametric identification of the power transmission line was performed. Based on this, the model of this transmission line was adjusted; repeated modeling was carried out, and errors were calculated. The modeling results showed a high accuracy when calculating the modules and phases of voltages using the identified model. The average error value for current modules was 0.6%, and for angles, it was 0.26°.

Relay Protection Device Reliability Assessment Through Radiation, Fault Injection and Fault Tree Analysis.

Relay protection devices must operate continuously throughout the year without anomalies. With the integration of advanced technology and process chips in secondary equipment, new risks need to be addressed to ensure the reliability of these relay protection devices. One such risk is the impact of α-particles inducing single event effects (SEEs) on the secondary equipment. To date, there has been limited assessment of the effects of α-particles on relay protection devices from a system perspective. This study evaluates the impact of SEE on relay protection devices through a Monte Carlo simulation, which is verified by α-particle radiation, fault injection, and fault tree analysis. It discusses the influence of SEEs with and without hardening measures in place. Additionally, this study examines the soft error probability when the target processor runs both general workloads and specific application workloads. The current research proposes a low-cost and effective reliability assessment method for secondary equipment considering single event effects. The findings provide new insights for the enhancement of future electric power grid systems.

Digital twin for advanced optimal coordination scheme of distance and Dual-Stage overcurrent relays

Integrating Distributed Generators (DGs), particularly renewable energy sources such as wind systems, into traditional power network presents significant protection coordination challenges. This study introduces a new optimal coordination scheme for distance and double-Stage Overcurrent (OCR) characteristics relays, utilizing digital twin technology. The proposed dual-stage of OCR protection to enhance the efficacy of the coordination between distance relays and OCRs. By employing advanced digital twin models and Hardware-in-the-Loop (HIL) testing, the proposed scheme aims to enhance fault management and relay coordination for microgrids. The scheme’s effectiveness is evaluated using a reference power network (CIGRE radial and mesh network) with and without wind systems under various fault types and locations. The study demonstrates substantial improvements over traditional and modern dynamic distance relays coordination approaches, including a reduction in maximum tripping time from 0.85 s to 0.19 s with the dual-stage scheme. Comparative analysis of digital simulation and physical twin relays further validates the accuracy and robustness of the proposed scheme.

Impacts of grid‐forming inverters on distance protection

AbstractGrid‐forming (GFM) inverters are anticipated to play an essential role in facilitating the integration of renewable energy in bulk power systems. The fault response of GFM inverters and its impact on traditional protection schemes are ongoing research topics. Distance protection is today one of the most commonly applied protection schemes and depends on multiple system preconditions for reliable operation—many of which may no longer hold in systems with a high penetration of inverters. This paper investigates the impacts of GFM inverters on distance protection, with the main objective of providing an improved understanding of the topic. Important interoperability issues are highlighted with simulation results and elaborated upon based on the theory behind the distance relay model and the behaviours of GFM inverters during faults. The simulations consider numerous fault types and two GFM inverters with different current‐limiting control techniques in their fault‐ride through strategies. Results indicate several challenges that state‐of‐the‐art distance relays may face with GFM inverters.

Reliable life optimization of a dual magnet differential polarisation relay based on digital model

Reliable life optimization of a dual magnet differential polarisation relay based on digital model

Enhancing Performance of Distance Relay Zone 3 Under Stressed Conditions Using an Angle-Based Algorithm

Enhancing Performance of Distance Relay Zone 3 Under Stressed Conditions Using an Angle-Based Algorithm

Online Transient Stability Assessment Implementing the Weighted Least-Square Support Vector Machine with the Consideration of Protection Relays

Online Transient Stability Assessment Implementing the Weighted Least-Square Support Vector Machine with the Consideration of Protection Relays

Field analysis of directionality measurement with inverter based resources in India

AbstractRenewable energy sources are getting integrated into the electrical power network since many years. The characteristics of these sources are completely different from traditional synchronous generators. This is posing challenges for power engineers from system protection and control perspective. Cases of maloperations of protective relays have been a focus of research across industries and universities. India has been growing in deploying distributed energy resources. Most of the maloperations reported relate to transmission line protection. Studies on maloperation of directional element are not duly addressed from Indian grid perspective. Few cases from India have been chosen for research. Fault data from Type‐4 and Type‐3 wind plant and solar park has been analysed and compared with literature reports. The objective of this paper is to document the behaviour of directional elements for a distributed energy resource connected system in India. In addition, aim is to understand the gaps from existing research to the behaviours of the current directional protections. This would help in identifying mechanisms to ascertain directionality for similar systems in the future. The conclusion from the paper is that the detection of fault direction must be completed before the time inverter control kicks in to operation in any algorithm.

Diagnosis and risk evaluation of hidden fault at voltage and current acquisition section of relay protection equipment based on primary and secondary information fusion

Diagnosis and risk evaluation of hidden fault at voltage and current acquisition section of relay protection equipment based on primary and secondary information fusion

Online automatic analysis application methods of power grid fault and relay protection operation

Online automatic analysis application methods of power grid fault and relay protection operation

Evaluation of open-phase detection technologies: relay protection logics and UL 1741SB certified inverter

Evaluation of open-phase detection technologies: relay protection logics and UL 1741SB certified inverter

The connotation and architecture of the knowledge graph of relay protection defect diagnosis

The connotation and architecture of the knowledge graph of relay protection defect diagnosis

Volt-VAr Management System

In this paper, the newly developed system has been integrated with auxiliary systems such as GIS (Geographic Information System), SCADA-DMS, and Field Device Controllers. It monitors the active and reactive power flow of feeders at TEİAŞ (Turkey's Electricity Transmission Corporation) transformer stations, while enabling the remote monitoring and automatic switching of reactors, capacitors, and MCR (Magnetic Controlled Reactors). Optimized reactive power and voltage management with the VVMS (Volt-VAr Management System) improves the power factor, reduces technical losses, and lowers energy costs. It also prevents low or high voltage issues through voltage regulation, thereby improving power quality. Additionally, reactive power management performs necessary calculations to ensure that inductive and capacitive limits are not exceeded, and the relevant equipment can be controlled remotely or via protection relays. The system aims to reduce energy losses and voltage drops, providing more efficient grid management.

Optimal Coordination of Directional Overcurrent Protection Relays Using Genetic Algorithm

This paper studies on establishing the mathematical optimization formulation to coordinate the operating times of directional overcurrent relays in transmission networks. The objective function of this optimization formulation is to minimize the total operation time of all directional overcurrent relays, and it must satisfy the highly nonlinear constraints such as the time multiplier setting range, the plug setting range, and the coordination time interval between the primary and backup relay pair. The optimal variables consist of the time multiplier setting and the plug setting which are determined by applying the genetic algorithm on MATLAB software. This optimization formulation is evaluated and validated via the simulation results of the test systems including the 4-bus network and 9-bus network. These test systems are modeled and simulated by using PowerWorld software to calculate the power flow results in the steady state and the short-circuit currents flowing the primary/backup relay pair. The simulation results confirm that the operating time coordination of directional overcurrent relays is capable of meeting the requirements of a relay protection system, improving the reliability of power system.

An enhanced human conception optimizer for over-current relay coordination problem in distribution system

An enhanced human conception optimizer for over-current relay coordination problem in distribution system

Development and Application of A Wearable Technology Product That Detects and Informs The Presence of Electrical Energy

Electrical energy has both positive and negative effects nowadays, with the potential to cause property and human loss. Technical professionals working at electrical energy generation, distribution, and utilization points may die due to carelessness or neglect. Although there are protection elements (fuses, residual current protection relays, etc.) in electrical panels that interrupt the flow of electrical energy in the event of a shock, there may be working areas where energy cannot be cut off due to incorrect electrical connections caused by unauthorized people interacting with the panel. Existing protective components may be insufficient. The experiments include both wired protection elements and wireless detection elements. However, they need to be enhanced because they have limited detection distances. Furthermore, using an ergonomic design can improve operability. New protection and warning features must be designed using developing technology. To prevent employees from being shocked by being exposed to electrical energy in the workplace, AC voltage can be detected without contact using this study, which includes the design and test results of a wearable technology product that warns when electricity is present. An electrical circuit that technical staff can wear on their finger detects voltage without contact and displays the existence of energy with a red LED. It was discovered that the test circuit detects 230V AC electrical energy up to 8 cm away and warns with light.