Overcurrent relay testing procedure Feb 6, 2025 · In this detailed guide, we’ll walk through the Secondary Injection Test procedure step by step, provide expert insights, and explain its importance in real-world applications. This article is to guide the responsible persons in conducting Directional Overcurrent and Earth Fault Protection relay (67/67N) Commissioning and test procedure. As modern protective relays become increasingly more powerful and complex, many relay testers continue to use test procedures and philosophies that are based on previous generations of relays and their limitations. This document summarizes test results for directional protection relay. Acceptance testing, commissioning, and startup will include control power tests, current transformer and potential transformer tests, and any other device testing associated with the protective relay. There is no need to disturb wiring, which obviates the hazard of open-circuiting current transformers, and there is generally no need for any switching in the current transformer or relay This relay tester is capable of testing the time-delay characteristics of overcurrent relays, motor overload relays, and molded-case circuit breakers rated up to 125 amperes, when following the recommended test procedure of testing the time delay of these devices at three times their rating. Current transformer releases are used on breakers in substations where no grid independent supply voltage is available. Feb 23, 2021 · I already covered how to test a modern intelligent electronic device (IED) in the How to Test Protective Relays online seminar, but my ideas about relay testing have evolved since then. Keyword: - Overcurrent relay, circuit breaker. Work with special test set-ups that simulate the substation in the classroom. The disk shaft carries Commissioning Siemens Relays ( 7SJ802 - 7SD522 - 7SJ85 )Get your team access to 30,000+ top Udemy courses anytime, anywhere. May 22, 2025 · Explore the step-by-step LT protection relay testing procedure, including preparation, test setup, functional tests, & safety considerations, to assure dependable low-tension system protection. These relays can replace the following GE electromechanical & static relay types that require a time overcurrent range of 0. Caution, risk of electric shock Caution, hot surface Caution, risk of danger. Consult the relevant user documentation. The DIAC, DIFC and DSFC line of digital single phase, self-powered relays offers customers a single relay that replaces the hundreds of different models of IAC, IFC and SFC relays. It details tests of the relay's metering accuracy, overcurrent protection performance for phases R, Y and B, and checks of LEDs and output relays. The relay was found to meet expected performance in pickup current, timing, directional operation, and operation of output devices. by J. 1. For example, on a three-phase overcurrent relay, it would be necessary to inject a current at the phase A CT and verify that the relay and associated breaker trip. Learn about tools like secondary injection test sets. The testing procedures involve using a Fereja test set to apply Hi in this demo we show how to do substation protection test produce and how to connect testing kit with relay and how to perform substation test with omicro The MTS-5100 Protective Relay Test System What Can It Do For You? The MTS-5100 is the most powerful all-in-one relay test system with a direct front panel interface for all functions, without exception! The ideal system for testing and calibrating protective relays using traditional test techniques or applying realistic power system simulations. After the foundation is laid, you will find practical step-by-step procedures for testing the most common protection applications for: voltage, overcurrent, differential, and line distance relays. It describes pickup and timing tests for overcurrent, directional, earth fault, and restricted earth fault relays. Overcurrent releases are commonly used together with self-powered overcurrent protection relays. Model MS-2A is a self-contained test set that incorporates a variable high-current output and appropriate control circuitry and instrumentation for testing thermal, magnetic or solid-state motor overload relays, molded-case circuit breakers, ground-fault trip devices and overcurrent relays. Key steps include connecting a current injection kit, applying currents or voltages to induce relay operation, and checking that pickup thresholds and operation times match specifications. Test each part of the entire system at least one time. May 7, 2015 · INTRODUCTION This application guide describes how to test the voltage-restrained time-overcurrent element (51V) in an SEL-700G Generator Protection Relay. It also assists individuals responsible for relay maintenance and testing to share software, test equipment, test routines, and relay specific information. Pre set value or protection relays are verified or tested through test equipment. The Overcurrent test module is designed for testing directional and non-directional overcurrent protection functions with DTOC or IDMT tripping characteristics (short-circuit, thermal overload, zero sequence, negative sequence, and customized curve characteristics). Oct 29, 2020 · Protection Relays Testing Principles and some tricks/puzzles. Ask yourself, “What are the goals for this test?” and plan your test to meet those goals. It focuses on Directional Overcurrent relays, which have three essential parts for successful testing: current above pickup setting, correct direction, and polarizing signal. Mar 31, 2025 · Overcurrent protection relays play a crucial role in safeguarding electrical power systems by detecting and responding to excessive current conditions. This article is to guide the responsible persons in conducting Overcurrent, Under Current and Earth Fault Relays Test. This should not be mixed with ‘overload’ relay protection, which typically utilizes relays that function in a time related in Ensure optimum system performance, eficiency, and safety with preventive relay maintenance and testing Today’s challenges in relay maintenance and testing are many. Jul 23, 2021 · PDF | Motor protection relay | Find, read and cite all the research you need on ResearchGate This document provides a commissioning procedure for testing protection relays of a generator for a power plant project in Kendari, Indonesia. Modern relays have very different characteristics that require a different testing philosophy to ensure that they will operate when required. 5-15. Co-ordination procedure Correct overcurrent relay application requires knowledge of the fault current that can flow in each part of the network. The 50-element can be used independently or in conjunction with time overcurrent (51) functions. The procedures describe how to test the relay settings, pickup values, boundaries, minimum voltage pickup, and ensure safety is CAUTIONused without the Caution, risk of dangersign , indicates a hazard with a potentially hazardous situation which, if not avoided, may result in property damage. g. Finally the timer stops when the relay operates. Tests involve connecting a current injection kit and variac to inject current and measure relay operation times at different settings, ensuring they match expected parameters. To validate the relay’s performance, we set up a test scenario where a fault of 500 Amps occurs at a distance of 10 kilometers from the relay. 1- HT protection relay performance test: Now a days the digital protection relay mostly are using. The Motorvision2 has a wide ranging power supply, the supply can be anywhere from 80-265VAC and 80-265VDC. Due to rapid advancements in technology, it is not unusual for one utility or plant to operate multiple generations of relays all in one integrated protection scheme. This document provides step-by-step procedures for testing various types of relays, including undervoltage, overvoltage, synchronizing, overcurrent, loss of excitation, negative phase sequence, and earth fault relays. It explains that successful tests require the current to be above the pickup setting, in the correct direction, and with a polarizing signal. First relay performance test is carried out after commissioning after that relay testing is carried out as base of annually time schedule. Learn how proper relay coordination ensures fault Digital and numerical protection relays will have a self-test procedure that is presented in the relay manual. Testing overcurrent, undercurrent, and earth fault relays is crucial for ensuring the protection and reliability of electrical systems. Overcurrent relay testing is essential to ensure that the relay will correctly operate during fault conditions. (Pickup indication by LED, output contact, front panel display, etc…see previous packages of The Relay Testing Handbook for details) ¾ Set the Oct 19, 2007 · Meanwhile, testing and commissioning practices largely still focus on individual relays, not the protective relaying system. Visual checks of the relays and connections to test equipment are performed first. Checking digital inputs and output relays are operating as expected before injection tests. a APPLICATIONS Model MS-2A is capable of testing the time-delay characteristics of overcurrent relays, motor overload relays and molded-case circuit breakers rated up to 125 amperes, when following the recommended test procedure of testing the time delay of these devices at three times their rating. doc / . 1 Pick-up and drop-off test Figure 3. This guide assumes that the user is familiar with testing time-overcurrent elements and understands basic terminal commands Having problems testing modern line distance impedance relays? Do your tests keep failing with no explanation? Find out why with this post! Directional Negative Phase Sequence Overcurrent Relay (67Q) Test Procedure. Learn how relay testing equipment, including secondary injection test sets, three-phase relay test sets, and digital relay testing, ensures power grid reliability. It details the purpose, scope, references, manpower, procedures, safety precautions, responsibilities, emergency procedures, and records requirements for testing the relays Learn how to efficiently test overcurrent, distance and transformer differential relays with the OMICRON Test Universe. The IAC relay is mounted in a drawout case, permitting front access to the relay for testing and maintenance. An important factor in analyzing test intervals is monitoring the self-test alarm of a relay. This document provides procedures for testing the differential relay settings on a P643 transformer protection relay. By applying various test currents, you can measure the time taken for the relay to trip and plot the inverse time-current characteristics. Here is a step-by-step procedure for testing an overcurrent relay: Overcurrent is used for automatic testing of directional and non-directional overcurrent relays with auto-assessment of the trip time characteristic, the directional boundaries of the current stages, and the pick-up/drop-off ratio. . This technique normally comprises the verification of electrical characteristics, insulating resistance, mechanical operations, & safety measures, among other things, to ensure the switchgear Feb 17, 2019 · The relay consists of three independent cup type overcurrent units each controlling its own target seal-in unit assembly. 43K subscribers Subscribed Jul 23, 2021 · PDF | Motor protection relay | Find, read and cite all the research you need on ResearchGate This document provides a commissioning procedure for testing protection relays of a generator for a power plant project in Kendari, Indonesia. May 1, 2008 · In this paper, the authors present an overcurrent protection-relay testing procedure by a applying special simulation hardware for a real-time power-system digital simulation (RTDS). Outline and panel drilling dimensions are shown in Figure 4. If we want to check health performance then we will have to test of relay. 🔧 REF620 Directional Overcurrent Relay Testing | DPHLPOC1 Module | Protection Relay Tutorial In this video, we demonstrate step-by-step testing procedures for the ABB REF620 directional Apr 24, 2020 · These techniques locate wiring errors, insulation failures, loose connections, and other problems that go undetected if only relays are tested. A comprehensive testing program should simulate fault and normal operating conditions of the relay. Nov 21, 2024 · Discover how to streamline overcurrent relay operating time testing with a practical tool designed for field testing, commissioning, and maintenance. My Protection Guide Oct 8, 2019 · Digital and numerical relays will have a self-test procedure that is detailed in the appropriate relay manual. It describes establishing communication with the relay, downloading and modifying settings, and testing the differential protection, bias characteristics, second harmonic blocking, and overcurrent elements. These tests should be followed to determine if the relay is operating correctly. May 31, 2024 · Calibration of protection relays is critical to the reliability and safety of electrical power systems. Relay Testing | Electromechanical OverCurrent Relay | Power Systems Lab | Practically Tested Naufal's Electrical Hour 1. 2. The phase B and C CT also would 2. OVERCURRENT PROTECTION FUNDAMENTALS Relay protection against high current was the earliest relay protection mechanism to develop. Powell presented at PEA 1975. The dropout test involves applying a current above the pickup value for an extended time, then gradually reducing it Model MS-2A is a self-contained test set that incorporates a variable high-current output and appropriate control circuitry and instrumentation for testing thermal, magnetic or solid-state motor overload relays, molded-case circuit breakers, ground-fault trip devices and overcurrent relays. - Routine factory production tests to check for defects during manufacturing. In this paper, the authors present an overcurrent protection-relay testing procedure by a applying special simulation hardware for a real-time power-system digital simulation (RTDS). Mar 4, 2010 · The document provides procedures for testing various line control and relay panels. The relay has a pickup threshold of 100 Amps and a time delay of 0. Sep 16, 2025 · We ensure the flow of electricity in our homes by testing solid state relays. A capacitor and variable re sisto r connected in series with the inner coil on the upper laminated structure make up the phase-shifting c irc u it. The test current is adjusted to the desired level with the relay short circuited by a normally closed contact on the starting contactor. What is the Secondary Injection Test Procedure? The Secondary Injection Test procedure involves injecting a simulated current or voltage signal directly into a protection relay. c and directional e. Tolerance ranges for Apr 4, 2023 · The Purpose Of Tests Secondary injection tests are always done prior to primary injection tests. Feb 26, 2025 · The SEL-751 Directional Overcurrent Relay (CTC) is essential for protecting electrical systems, ensuring efficient fault detection and isolation. The relays in this report were tested via a dynamic test method where each element’s pickup and timing results are proven by applying a power system simulation at either end of the relay element’s operating tolerances with two timers. Nov 27, 2024 · Discover the types of protection relays, their applications, and essential testing procedures to ensure grid reliability and safety. Caution, lifting hazard Caution, hand entanglement hazard Notice, non-ionizing radiation Direct current It is common practice to individually test the components of a protective relay scheme (e. These tests should be followed to verify if the protection relay is operating correctly. 9 Amps and an instantaneous overcurrent range of 1-159 Amps: The operational condition of the relay is tested by means of ordinary relay test equipment. A similar test procedure can be followed for the SEL-300G Generator Relay (firmware Version R240/R320 and later). One method to mitigate exposure to tripping undesirably for high current external through faults is to supervise the sudden pressure relays with an instantaneous overcurrent relay that will block tripping for currents that exceed a relatively high threshold, at least the loadability rating or phase time over current relay pickup (if used) of Can you give me an idea, how to test SIEMENS 7sj622 directional o. There are still tens of thousands of electromechanical overcurrent relays still in service all over the world, and if you're fortunate enough to be employed in maintaining, testing, and To proper transmit the electric power from sending end to receiving end without suffering from any difficulty and dangerous condition. Become familiar with the test procedures in theoretical and hands-on sessions and get to know the benefits of automated testing and reusable test templates. Perform the tests required as per the following test connection for injection of secondary Current values to the relay: Aug 23, 2022 · Learn how to test overcurrent relays by watching the author of The Relay Testing Handbook test a variety of electro-mechanical and digital overcurrent relays with multiple test-sets in this online seminar with. As a last step the reason for protection testing is given and shown how it can be done. Then click Customize. It describes pickup and timing tests for overcurrent, directional, earth fault, and other relays. The purpose of secondary injection testing is to prove the correct operation of the protection scheme that is downstream from the inputs to the protection relay (s). An external fault is illustrated. 3. The dropout test involves applying a current above the pickup value for an extended time, then gradually reducing it How to Test Overcurrent Relays: An Introduction to Protective Relaying Online Seminar – Final 2022 Update All of the main videos of Lesson 6: How to Test Overcurrent Elements in IEDs have been recorded and are in the editing process! The document discusses testing directional overcurrent relays. The goal is to determine pickup and dropout values under different conditions. A Comparison of Static and Electromechanical Time Overcurrent Relay Characteristics, Application and Testing. Such a test also includes the matching transformers, output contacts and the accuracy of the operate values. The tests were conducted using OMICRON test equipment (CMC256plus, CMC156) and software (Version 4. For example, developing a test program for a complicated microprocessor-based relay could take several months. This document outlines the method statement for testing overcurrent and earth fault (OCEF) relays. You will learn how to efficiently test overcurrent, distance and transformer differential relays with the OMICRON Test Universe. Relay Startup and Commissioning New relay installations require startup and commissioning to ensure proper protection for your system. Our experience in advanced utility and industrial relay applications includes: General inspection of equipment Wiring diagram check with functional and point-to-point wiring checks Insulation resistance measurements Relay device testing Current and voltage ANSI 24 – Overexcitation protection This test procedure shows how to test a transformer relay with OMICRON Quick CMC module Directional Overcurrent: Enable the directional overcurrent in the DIGSI. Mar 8, 2025 · This repository contains comprehensive test reports and analyses for three critical electrical protection systems: Overcurrent Protection (OCP) Relay, Differential Protection Relay, and Distance Protection Relay. To help professionals master the testing and maintenance techniques of this device, Conprove offers a free, complete tutorial, covering everything from basic concepts to advanced practices. This 3 sentence summary provides the key information from the inverse time overcurrent protection relay test report: The report details the testing and settings of a relay for overcurrent protection on a plant section, including injected currents, measured times, and actual times for Conclusion: Testing the Induction Type and Microprocessor-Based Overcurrent Relays using a Relay Testing Kit allows you to assess their response under different overcurrent conditions. The pickup test involves gradually increasing the fault current until the relay operates, then reducing it to determine the minimum value needed for the relay to operate. Burke, R. Select the DMT/IDMT Directional Phase/E Overcurrent. Regular testing helps identify and rectify issues before they lead to significant problems, ultimately protecting both the electrical infrastructure and the people who depend on it. Summary: Learn how to efficiently test overcurrent relays with the OMICRON Test Universe. How can we be certain that we are fully testing and commissioning relay systems? Have we improved simplicity and reliability or just shifted the complexity? Overcurrent Release Test The Overcurrent Release Test is used to determine the current which trips the breaker. Ground or neutral instantaneous overcurrent elements can have the designations 50N or 50G depending on the relay manufacturer and/or relay model. pdf), Text File (. J. These protection devices, namely relays, can respond instantly to serious problems, or allow for short recovery time following minor, routine events. All of your test procedures should follow this path. My Protection Guide Nov 9, 2024 · Furthermore, this handbook seeks to fully provide one with knowledge on electrical tests, check lists, testing criteria, test forms, circuit connection diagrams needed for testing, Documented for review and future comparison with the outcomes of maintenance tests are the test procedures and test results. The goal is to validate relay settings, performance, and compliance with Learn how to efficiently test overcurrent, distance and transformer differential relays with the OMICRON Test Universe. The document provides guidance on performing secondary injection tests on a Motorvision2 relay to verify correct operation of its protective functions. This document discusses the various types of testing required for protection equipment, including: - Type tests to prove the relay meets specifications and standards under abnormal power conditions. These relays operate based on preset thresholds, ensuring timely isolation of faults to prevent damage to equipment. The procedure tests relays for loss of field, reverse power, overcurrent, over and under voltage, and over and under frequency. Get familiar with the test procedure in hands-on and theoretical sessions. Complexity is added when companies opt to hire different contractors to perform these tests. Overcurrent relay testing is a critical aspect of electrical power system maintenance, ensuring safety, reliability, and compliance. Apr 3, 2017 · The overcurrent – time diagram is introduced and explained why different trip times make sense to obtain selectivity of a system with more than one relays. From this basic method, the graded overcurrent relay protection system, a discriminative short circuit protection, has been formulated. We did not OCEF RELAY TESTING - Free download as Word Doc (. If currents greater than 15 A are applied, allow sufficient cooling time between tests. Mohamed Ibrahim AliRegional application specialist Testing Before carrying out overcurrent injection tests it is always worth confirming that the digital inputs and output relays operate as expected, this can save a lot of time later on when it appears that a function fails to work correctly. It includes sections for operation current checks, sensitivity checks, and operation time measurements for different phases. Based on our test results, the Beckwith Electric Co M-3425A and the SEL-300G relays are operating within their specifications as programmed. 1 Connections for current pick-up/drop-off test (no storage) Dec 13, 2017 · Why Primary Injection Tests? This type of test involves the entire circuit – current transformer primary and secondary windings, relay coils, trip and alarm circuits, and all intervening wiring are checked. docx), PDF File (. Testing can be accomplished, without removing the relay, by using XLA test plugs. txt) or read online for free. Then specific test steps are outlined for Apr 2, 2024 · The Site Acceptance Test (SAT) Procedure for Medium Voltage (MV) Switchgear Panel assures that the switchgear panel functions properly and meets the specifications and criteria at the installation site. F. It outlines the purpose, scope, references, manpower, procedures, safety precautions, responsibilities, and records for testing directional overcurrent and earth fault relays. The Relay Testing Handbook: Testing Over-current and earth fault relays 1. This guide is designed to inform engineers, power system operators, and technical enthusiasts about the calibration process, its importance for different relay types, and best practices based on engineering principles and industry standards. Aug 1, 2011 · If the relay is a motor overload relay, hard wired in a motor starter, the test techniques are different than if it is a modern digital relay mounted in a protection panel with test switches. 29K subscribers 53 Aug 13, 2018 · Among the various possible methods used to achieve correct relay co-ordination are those using either time or overcurrent, or a combination of both. This document provides a method statement for directional overcurrent protection testing. Applications How Does Instantaneous and Time-Overcurrent Protection Work? Overcurrent protection prevents damage from the overheating of critical components and conductors, further preventing fires and injury. Since large-scale tests are normally impracticable, system analysis must be used – see Chapter [A3: Fault Calculations] for details. To measure the drop-off current and contact timing, inject a gradually decreasing current until the drop-off point is reached The document provides testing procedures for various line control and relay panels. Below is a detailed guide step by step on how to perform testing for the 67Q relay: Perform General Visual Inspection as per work instructions. This is sim ilar to the standard element as used in watthour meters, except the actuating coils above and below the operating disc are connected in series. f fault relay by using omicron . Each contractor will focus on its scope of work and most likely not spend time considering the big picture of how Overcurrent Relay The differential circuit using a simple overcurrent relay is shown in Figure 5. The data required for a relay setting study are: Mar 9, 2021 · RIO Function Over Current, Define Element Characteristic, Pick-Up/ Drop-Off Test Testing of the Overcurrent and Directional Overcurrent Functions (67, 67N, 50, 51, 50N, 51N) Pickup Test Procedure - – Time Overcurrent (51) Element TestingUse the following steps to perform a pickup test if the setting is less than 10 secondary Amps: ¾ Determine how you will monitor pickup and set the relay accordingly, if required. The internal connection diagram is shown in Figure 1. 2 seconds. The tests confirmed the relay is healthy and Over Current Relay test Report - Free download as PDF File (. How to Test Overcurrent Relays: An Introduction to Protective Relaying Online Seminar – Final 2022 Update All of the main videos of Lesson 6: How to Test Overcurrent Elements in IEDs have been recorded and are in the editing process! The document discusses testing directional overcurrent relays. The disk is actuated by a wattmetric type current operating element. Find out what the relay is supposed to do without looking at the settings in the relay. The IAC relay may also include one or more hinged armature instantaneous overcurrent units, with integral target. It includes connections, settings, test procedures and parameters to monitor for each relay type. Why done prior to primary injection tests? This is because the risks during initial testing to the LV side of the equipment under Overcurrent relay testing procedure Testing and Commissioning of Directional Overcurrent and Earth Fault Protection Relays Requires Careful Planning and Attention to Safety Precautions. I1 I2 F The thermal rating is 250 A for 1 second or 62,500 A for 2 seconds. Each contractor will focus on its scope of work and most likely not spend time considering the big picture of how Dec 13, 2018 · اختبارمرحلات الوقاية ضد زيادة التيار الغير أتجاهيTesting Overcurrent RelaysWebinar from OMICRONEng. This document describes procedures for testing the pickup and dropout values of overcurrent relays. This helps to test the relay’s Oct 17, 2017 · The electrical system reliability, component and circuit protection, and overall safety are directly related to the reliability and performance of the overcurrent protective device and can depend upon whether the required testing and maintenance are performed as prescribed for the overcurrent protective device utilized. , instrument transformer tests, relay tests, wiring checks, trip checks, and end-to-end tests). Overcurrent relays, overvoltage relays, undervoltage relays and all differential relay test features can be added to the test report with the push of a button. 31). The paper “Philosophies for Testing Protective Relays” describes an approach to testing digital relays and the factors that affect a maintenance interval [2]. Applications The document is a field test record for overcurrent relay quality control, detailing various protection functions including overcurrent, earth-fault, under-voltage, restricted earth-fault, and differential protection. Testing overcurrent protection by energizing the test input, setting the trip level to 150%, and injecting over 150% of the To proper transmit the electric power from sending end to receiving end without suffering from any difficulty and dangerous condition. Key steps include: 1. freja or any Numerical testing instrument? Directional overcurrent testing with SVERKER900 Electrical Engineering Knowledge Sharing 9. If it is an older electro-mechanical relay in a draw-out case the way you connect the test set and the trip timing devices is different. Koch, and L. Implementation of over current relay and testing of circuit breaker & over current relay are present using different simulation software’s and techniques. The final lesson in this How to Test Overcurrent Relays online seminar will show you how I would test an overcurrent element inside an IED today. SEL Test Procedure Negative-Sequence Volt-Pol Directional Overcurrent Element I am writing to enquire about 67N test procedures, specifically Schweitzer relays. The relay is contained in a three unit doudle ended L2 size case. By energizing the starting contactor the short circuit across the relay is released and the timer starts. It then discusses how to simulate faults to provide these three requirements when testing relays that use different types of polarizing signals, such as phase-to-phase voltages or negative Oct 10, 2019 · PDF | MV SWITCHGEAR PROTECTION RELAYS INSPECTION AND TEST PROCEDURE | Find, read and cite all the research you need on ResearchGate Mar 4, 2025 · Discover the essential types, applications, and testing procedures for reclosers. Enter into the Setting Group A. Hi in this demo we show how to do substation protection test produce and how to connect testing kit with relay and how to perform substation test with omicro The MTS-5100 Protective Relay Test System What Can It Do For You? The MTS-5100 is the most powerful all-in-one relay test system with a direct front panel interface for all functions, without exception! The ideal system for testing and calibrating protective relays using traditional test techniques or applying realistic power system simulations. Perform relay testing to ensure accurate operation during current fluctuations. Relays are tested on This document provides step-by-step procedures for testing various types of relays, including undervoltage, overvoltage, synchronizing, overcurrent, loss of excitation, negative phase sequence, and earth fault relays. Testing overcurrent protection by energizing the test input, setting the trip level to 150%, and injecting over 150% of the May 31, 2024 · Suppose we are testing an overcurrent relay used for feeder protection in a high-voltage transmission system. Enter the setting value in the DIGSI. Here's complete guide on how to test solid state relay.