They interact with each other and cause a gradual spiral of decline in insulation quality. In 1996, the insulated conductor industry determined that dc withstand testing of the plastic xlpe insulation systems either in the cable factory as a routine production test or after installation as the higher voltage proof test was detrimental to the life of the insulation and therefore discontinued recommending dc testing. After dc overpotential test is completed, the insulation resistance test is done again to assure that the cable has not been damaged by the hipot. Simple megger test for 4 core cable to locate insulation.
This test is used to detect conductor insulation damage that may have been caused during installation. Insulation resistance test data may be used to establish a trending pattern. Xltrace system installation and operation manual for pipe freeze protection and flow maintenance. Insulation can also be damaged when exposed to moisture, excessive heat, or certain chemicals. It involves applying the test voltage for a short time 30 or 60 seconds and noting the insulation resistance reading at. An insulation resistance tester is a test instrument that measures current that leaks through the insulation into ground. These test methods detail the standard procedures for testing hookup wire insulations including all components of the insulation system used on single insulated conductors or an assembly of single insulated conductors such as a cable bundle and harness or flat ribbon cable. Cable testing revision 1 june 2, 2011 page 5 of 8 dependant on the type of test being performed i. A guide to diagnostic insulation testing above 1 kv surgetek. Yet, without the partial discharge analysis some of the severe cable insulation defects may be overlooked.
Cable insulation resistance measurements made during cable fire tests manuscript completed. Insulation resistance testing of heat trace cable electric heat tracing systems are widely used inprocessindustriesand have applications in many other areas,as well. Pd testing of power cables for oilpaper transmission class, primarily use on line pd all xlpe and epr cables. Compare cable data with drawings and specifications. Do not power the heating cable when its on the reel. Testing of hv cables supplementary information page 1 of 24 reference sp0407r02 ver 2 ergon energy corporation limited abn 50 087 646 062 1. Find here insulation testing and continuity, power protection, power transformer testing, power cable infrastructure, cable fault location, general electrical test. Locate the connection point of the wire or cable you want to test so you have access to the exposed conductors.
Whether it involves the connection cables, the sectioning and protection equipment, or the motors and generators, the electrical conductors are insulated using. Insulation resistance values must be according to the manufacturers published data. A cable insulation test is basically a continuity test, so the power to the circuit must be off. Cable types, design, and associated insulation faults. The insulation resistance test is not recommended for mediumvoltage cables. Astm d3032 16 standard test methods for hookup wire insulation. Understanding insulation resistance testing pdf 0712. The top terminal might be the center conductor of a power cable, and the bottom terminal, its shield.
The applied test voltage is raised in steps, with measurements first taken up to 1uo, or normal line to ground operating voltage. Cable insulation and continuity test report no report. One test was run with the insulation resistance measurement system providing. Proper setup connected equipment switches, relays, buswork, transformers, etc. Deviations from the baseline information permit evaluation of the insulation. The way to complete the online megger test report on the internet. The following is a summary of insulation resistance ir testing commonly referred to as megger testing of low voltage cables rated less than 5 kv, recognized by nexans.
Learn how insulation resistance test is done developed early in the 20th century, the insulation resistance ir test is the oldest and most widely used test for assessing the quality of insulation. The limitation for this test is in its interpretation of the test measurements. Sep 26, 2018 a cable insulation test is basically a continuity test, so the power to the circuit must be off. Insulation resistance testing guide chauvin arnoux. This test method is sometimes also referred to as an absorption test because it is based on the absorption effect of good insulation compared to that of moist or contaminated insulation, which gives you a clearer picture of insulation quality even when a spot reading indicates an acceptable condition. Ieee recommended practice for testing insulation resistance. Loss angle or dissipation factor testing, is a diagnostic method of testing cables to determine the quality of the cable insulation. Cable insulation resistance testing introduction need of insulation testing. A cable insulation resistance test is a test that is performed by applying 500 v or more between the conductor and ground and measuring the resulting leakage current. Insulation resistance testers can be used to determine the integrity of windings or cables in motors, transformers, switch gear, and electrical installations.
Where public access is possible, position safety observer and barricade exposed ends of cable during insulation test. Simple megger test for 4 core cable to locate insulation fault sustainable every day. Megger test report fill out and sign printable pdf template. If the tan delta numbers indicate good cable insulation, the test voltage is raised up to 1. Nevertheless, dc withstand testing is effectively applied to detect insulation errors to do with cable accessories or environmentally. There are five basic causes for insulation degradation. The universal testing standard for rotational equipment, ieee 432000, increased the test voltage recommendation to 10 kv for equipment rated 12 kv and above. The measured resistance indicates the condition of the insulation between two conductive parts. Pdf crosslinked polyethylene xlpe has been used as the insulation for polymeric power cables for its superior advantages. When testing with dc highvoltage, capacitive charging current, insulation absorption current, insulation leakage current, and by. Like a visit to the doctors office, each test examines the test item in a different way. Pvc polyvinyl chloride is the most commonly used thermoplastic insulator for cables. Enter your official identification and contact details.
Standard for acceptance testing specifications for electrical. Either turn off the breaker or, if youre testing the wiring in a piece of equipment, unplug it. Inspect bolted electrical connections for high resistance using one of the following methods. Electrical utility field testing for mediumvoltage cables. Paperinsulated lead covered cables pilcfundamentals. Thermoplastic thermoplastic compounds are materials that go soft when heated and harden when cooled. Position hv test in progress signs at all ends of the hv cable prior to testing. May 02, 2018 test voltage is applied to the cable while the tan delta test set takes measurements.
Cable insulation materials the following materials are typically used for cable insulation. Standard for acceptance testing specifications for. Typically, the applied test voltage is raised in steps, with measurements first taken up to 1uo, or normal line to ground operating voltage. Electrical stress insulation is designed for a particular application. The megger technical library provides access to a range of additional content and resources such as technical guides, application notes and more. Before measuring in order to obtain meaningful insulation resistance measurements, the electrician should carefully examine the system under test. Inspect exposed sections of cables for physical damage.
A guide to diagnostic insulation testing above 1 kv. For complete insulation testing capability of all highcapital equipment, megger. Testing of high voltage cables manual horizon power. Pdf cable test and breakdown voltage determination of.
The insulation resistance test is the second test required by the electrical safety testing standards. Several layers of the soft and friable insulation are wrapped around the cable in long, wide strips. Withstand or hipot cable testing withstand or hipot testing is used to evaluate the condition of cable insulation during installation, acceptance, or maintenance testing. Never connect the insulation tester to energized conductors or energized equipment and always recommendations. Pdf insulation resistance testing of low voltage cables. The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. Introduction this reference is intended to give a basic overview of insulating materials that can be used during high voltage withstand testing, in particular cable testing. Perform an insulation resistance test utilizing a megohmmeter with a. High power test and diagnostics combination for medium voltage cables.
Each core to ground continuitypoint to wire check with low voltage tester check correct installation of cable glands. Electrical insulation starts to age as soon as its made. Meggar testing excerpt from prysmians wire and cable. This document will focus only on the tests that are of importance for field installers which are described as installation and maintenance tests. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. Cable insulation resistance measurements made during cable. A properly implemented vlf test will not cause damage to good insulation, but will reveal many cable system defects during the test duration. The value of the test for diagnostic purposes is limited when applied to extruded insulations, but it has been proven to yield excellent results on laminated insulation systems. The complete guide to electrical insulation testing. During testing all cables and wiring must be completely disconnected from any equipment.
With a little recordkeeping and common sense, however, you can get a good picture of the insulation condition from values that are only relative. Understanding insulation resistance testing aemc instruments. Regular insulation resistance testing is one of the most cost effective, nondestructive methods of identifying ageing in. Testing of high voltage cables manual horizon power 1st edition february 20 prepared by field practices. The readings obtained from ir tests on nonshielded. In general, these systems are used to maintain a preferred temperature.
Testing and commissioning of mvhv cables example of asbestos paper insulation wrap on highvoltage cable inside an underground cable vault. Confirm cable terminations and lightning arresterssurge diverters are unbolted to perform tests where required. The significance of the data is very dependent on the environment in which the test measurements are taken. The advanced tools of the editor will lead you through the editable pdf template. It may be prudent in certain circumstances to pressure test the cable section prior to connection to the system where it is considered appropriate to do so. Insulation resistance testing test equipment depot. Raychem xltrace system installation and operation manual. This type of test is commonly referred to as go no go testing or dielectric withstand test, since the cable passes the test if no breakdown occurs. An equivalent circuit for electrical insulation is shown in fig. To evaluate a number of test results on the same piece of equipment, you have to conduct the test the same way and under the relatively same environmental parameters, each and every time. One test was run with the insulation resistance measurement system providing 24 vdc to two separate instrument cables being exposed to the fire. Each manufacturer is required to comply with the same set of tests according to the same test parameters. A 1954 camera is ideal for all applications in the building, electrical maintenance and.
Cable testing revision 1 june 2, 2011 page 1 of 8 cable testing excerpt from prysmians wire and cable engineering guide. Section 7 of the ansineta standard for acceptance testing specifications for electrical power equipment and systems may be reproduced and used on a cut and paste basis for the particular type of equipment to be tested. The following sections of the ansineta standard for acceptance testing specifications for. Oct 14, 2016 11 kv hv cable megger test tamil language. Woods, nrc project manager prepared for division of risk analysis and applications office of nuclear. Perform resistance measurements through bolted connections with a lowresistance ohmmeter, if applicable, in accordance with section 7. When overpotential testing cable, its common practice to conduct the insulation resistance measurement first and then proceed with the dc overpotential test if acceptable readings are achieved. Direct high voltage testing of cable insulation systems. Megger guide to electrical insulation testing pdf instrumart. Proof enough is the fact that european standards have been in place for years for vlf cable testing. Additional information on megohmeter testing of insulation resistance can be found by referencing meggers a stitch in time the complete guide to electrical insulation testing.
A guide to diagnostic insulation testing above 1 kv 5 what causes insulation to degrade. Understanding insulation testing anixter s engineers provide insight on common testing problems. When voltage is impressed across any insulation system, some current leaks into, through, and around the insulation. For complete insulation testing capability of all highcapital equipment, megger goes one step further. Whether it involves the connection cables, the sectioning and protection equipment, or the motors and generators, the electrical conductors are insulated using materials with high electrical. Ieee recommended practice for testing insulation resistance of rotating machinery 1. Ieee std 4002001 guide for field testing and evaluation of the insulation of shielded power cable systems. Insulation resistance testing is a nondestructive test procedure. Cable insulation can be nicked or scraped from individual conductors when pulled through raceways. A catalogue, for quick reference, of the range of megger test instruments for the maintenance of electrical power systems. Insulation resistance testing of low voltage cables in the field. Insulation resistance testing of low voltage cables in the. Because electrical insulation will exhibit dynamic behavior during the course of your test.
Since 80% of electrical maintenance and testing involves evaluating insulation integrity, the answer is very important. Aemc instruments testing methods and interpretation of the results shorttime or spotreading measurement this is the simplest method. V 1200 for three phase systems 1 5core cables only with. Cable insulation resistance measurements made during. The test measures the insulation resistance between the phases andor between phase and ground. Every electric wire in a facility, whether its in a motor, generator, cable, switch, transformer, or whatever is. This is done to try to predict the remaining life expectancy and in order to prioritize cable replacement andor injection. The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d. Understanding insulation resistance testing pdf 0712 technical assistance 800 34391. The current flowing through the cable s insulation would be that current noted as total current in the diagram. We limit our discussion to insulated cable systems built to transmit electrical power in bulk at the subtransmission and transmission voltage levels. Mar 12, 2018 simple megger test for 4 core cable to locate insulation fault sustainable every day.