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