New Method for OC Relay Coordination

Protection relays design and manufacture have arrived to a new level of advancement; hence, numerical relays have appeared recently. They combine all the functions of monitoring, control, and protection in one device. Also these relays have the ability to communicate with each other to share statuses and orders using GOOSE (generic object‐oriented substation events) messages based on communication protocols such as IEC61850. In this paper, a proposed method for overcurrent (OC) relay coordination has been introduced based on numerical relay features of several setting groups and communication capability. This work supposes that the coordination between feeder, bus section, and incomer protection relays, in a substation of single busbar configuration with bus sectionalizer (i.e., bus section), depends on the status of the bus section circuit breaker (CB) as a criterion for determining active relay setting group, to achieve a faster tripping action. ETAP has been used as a simulation software environment. And the simulation results show the advantages of the proposed method in reducing the time needed by the relay to clear the electrical fault. Siemens SIPROTEC series have been used as an example of numerical relays, specifically 7SJ64 as OC relay, which exists in the ETAP library.

Modelling and Implementation of Microprocessor Based Numerical Relay for Protection Against Over/Under Current, Over/Under Voltage

This paper includes the design and implementation of Numerical Relay that can protect the equipment against over-voltage, over-current and under voltage. Although, every power system is subjected to faults and these faults can severe damage to the power system. Therefore, it is necessary to observe and resolve in time to avoid a large damage such as blackouts. For this purpose, there should be some sensing devices, which give signals to the circuit breakers for preventing of power system damages. The multipurpose relays have much importance role in power system for sensing and measuring the amplitude of faults. Numerical relay provides settings of over-current, overvoltage and under voltage values. Simulations have been carried out using Proteus software along with tested on hardware with Arduino Uno Microcontroller that proves the working and operation of numerical relay.

Overcurrent and Earthfault Relay Coordination for Microgrid with Numerical Relay Features

This Paper deals with the Relay Coordination for microgrids by considering the symmetrical and unsymmetrical faults. A microgrid is an active distribution system in which the renewable energy sources and loads connected to feeders operate parallel or autonomously from the main power grid. In a microgrid, Overcurrent relays can be used as the protection device. When there is changeover from grid connected to islanded mode or disconnection of DG will lead to variation in short circuit current. So, the relay may fail to operate or there will be delay in operation. Relay Coordination is done on the basis of load flow and short circuit analysis. Simulation is done using the ETAP (Electrical Transient and Analysis Program) Software by taking the 9 bus 18 node system.

Performance Evaluation of a Generator Differential Protection Function for a Numerical Relay

This paper describes the advantages and disadvantages of a generator differential protection relay system which uses double slope characteristics of Areva P343, ABB REG670, SEL300G and GE G60. A Buon Tua Srah Hydropower Plant in Vietnam was selected as an example for the relay setting calculations of these characteristics. The performance of the introduced relay model was tested at various fault conditions in Matlab/Simulink. The results apply to the problems of solving the performance of the relay accurately and with reliable differential protection against internal faults, and keeping the generator stable on all external faults and in normal conditions. The simulation simplifies the process of selecting the relay and protection system. This can improve the quality of the protection system design early, thereby reducing the number of errors found later in the operation.

Adaptive quadrilateral distance relaying scheme for fault impedance compensation

Impedance reach of numerical distance relay is severely affected by Fault Resistance (RF), Fault Inception Angle (FIA), Fault Type (FT), Fault Location (FL), Power Flow Angle (PFA) and series compensation in transmission line. This paper presents a novel standalone adaptive distance protection algorithm for detection, classification and location of fault in presence of variable fault resistance. It is based on adaptive slope tracking method to detect and classify the fault in combination with modified Fourier filter algorithm for locating the fault. To realize the effectiveness of the proposed technique, simulations are performed in PSCAD using multiple run facility & validation is carried out in MATLAB® considering wide variation in power system disturbances. Due to adaptive setting of quadrilateral characteristics in accordance with variation in fault impedance, the proposed technique is 100 % accurate for detection & classification of faults with error in fault location estimation to be within 1 %. Moreover, the proposed technique provides significant improvement in response time and estimation of fault location as compared to existing distance relaying algorithms, which are the key attributes of multi-functional numerical relay