A dielectric withstand test or high potential or hipot test is an electrical test performed on a component or product to determine the effectiveness of its insulation. Commissioning tests for hv underground cables up to 33kv swp page 5 of standard work practice sp0407 ver 16 ergon energy corporation limited abn 50 087 646 062 this test is required for xlpe and paper lead cables. Oct 15, 2014 the purpose of the routine test is to determine that the production folks covered all their bases. Distance 250m 500m m 2000m cable size m 11kv or less 400mm2 250 125 60 30 185 240mm2 300 150 75 37. Hipot test voltages high potential test electrom instruments. The hipot test the dielectric voltagewithstand test is commonly known as the hipot test. A simple water metaphor may help clarify this condundrum. The 3kvac and 4kvac tests are a stresstest for the main transformer only.
The dielectric withstand test is a basic electrical stress test, conducted to. In order to pass the hi pot test, the production folks must make sure that they made it like the design engineer designed it. This guide provides a general overview of the regulatory framework and approval process and explores the specific manufacturing responsibilities and test procedures associated with electrical safety testing. Very low frequency vlf withstand testing is the application of an ac sinusoidal waveform, generally at 0. The limitation for this test is in its interpretation of the test measurements. To learn more, subscribe to the cirris systems channel and visit. Addressing the task of power cable diagnostics and fault location, the energy industry now offers a wide range of tools using various cable testing methods. For example, a minimum test time of 30 minutes is recommended for aged cable circuits. Dielectric withstand or hipot test the dielectric voltagewithstand test, or hipot high potential test, is designed to stress the insulation of your product far beyond what it will encounter during normal use.
Dc high potential testing dc hipot testing purpose dc hipot testing is used for proof testing shielded cables 5kv to 46kv in the field. Hipot testing can be conducted with a dc potential or ac potential and can be applied as a type 1, withstand test or a type 2, diagnostic test. Acceptable procedures for conducting hipot testing, although varying slightly in technique, have been standardized as either a withstand test or a timeleaking current test. If one circuit fails, there is a backup circuit in place. Cable testing rev 1 prysmian group cables, energy system. The current standards provided for the use of dc hipot testing for acceptance testing of cables are recognized by the current industry standards. This is primarily due to the availability of other test methods and the high levels of. The dc hipot leakage current technique, sometimes referred to as a megger test, involves the. Item 828a, 128point expansion module attaches to base of hvx21. Jan 16, 2014 other models in the 800 series follow a similar testing procedure, but today im demonstrate testing on a 15kvrated urd cable. Hipot testers get their name from the high potential high voltage they produce to perform dielectric withstand and insulation resistance tests. 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 dc hipot withstand test is a passfail test that has been applied to all types of cable and accessories.
Item 828, 128point expansion module attaches to base of hvx. The iec61010 standard applicable to testandmeasurement equipment also requires a 3kv ac test. Terminal spacing problems and tolerance errors in cables. The dc hi pot withstand test is a passfail test that has been applied to all types of cable and accessories. The test is a means to qualify a devices ability to operate safely during rated electrical conditions.
The test may be between mutually insulated sections of a part or energized parts and electrical ground. The significance of the data is very dependent on the environment in which the test measurements are taken. But faced with myriad standards, sometimes engineers need clarification about the nature of the tests appropriate for each standard, writes kent smith is applications engineer with xp. Vlf testing of shielded power cables by paul brooker, consultant to techrentals division of tr corporation.
Insulation resistance testing is a nondestructive test procedure. Unless the type test was marginal, the routine test, in the end, finds gross defects in the manufacturing process. Connect the ground lead of the hipot tester to a suitable building ground or grounding electrode conductor. The limited approach boundary for this hipot procedure at volts is 5 ft.
Hi pot testing can be conducted with a dc potential or ac potential and can be applied as a type 1, withstand test or a type 2, diagnostic test. In fact, these tests can result in damage to the cable insulation. These features are used with a dc hipot or ir test. A hipot test starts with all of the points in a cable held at 0v. In the boost or voltage withstand test process, as a result of short circuit, flashover, breakdown, such as over current, the current trip of relay protection, automatic voltage regulator power that test materials are not up to standard, at this time regulator should be back to zero, cutting off power supply, inspect the test products.
Due to the nature of a dc withstand test, setting high and low leakage limits can prove difficult. Ieee std 400 provides additional information on dc testing and evaluation of the insulation of shielded power cable systems c. This technical article provides general guidelines for high potential hi pot dc testing of mv power cables. Nov 26, 2018 a few simple steps ensure testing takes place safely when potentially lethal voltages and currents are involved in the testing process. Generally, vlf withstand testing calls for testing the cables up to 3u 0, where u 0 is the rated phase to ground voltage. A properly wired and insulated electrical system will have negligible current flow during this test. Dc hipot test at test start, there will be inrush current.
The test measures the insulation resistance between the phases andor between phase and ground. All tests made following cable installation and during the warranty period must be performed in accordance with the applicable specifications. Standard for acceptance testing specifications for electrical. Hipot test standards dc hipot test analysis electrom. A hipot test, also known as dielectric breakdown, is a simple test. The test voltages to be used vary depending upon whether the device or circuit is low or high voltage, a primary or control circuit and whether tested at the factory or in the field. To conduct these tests the main transformer is removed from the power supply and tested as a stand. The test duration must be in accordance with the safety standard. During the test cables are subjected to a test voltage significantly higher than what they experience during normal operating conditions. Dec 01, 2011 the limited approach boundary for this hipot procedure at volts is 5 ft. Hipot testing has long been a standard procedure for assuring the electrical safety compliance of electronic equipment. The iec61010 standard applicable to test andmeasurement equipment also requires a 3kv ac test.
Inadequate creepage and clearance distances introduced during the manufacturing process. The insulation resistance test is not recommended for mediumvoltage cables. Ac hipot testing ac high potential tests are conducted at voltages above the normal system voltage for a short time. Between contacts and shielded, the puncture voltage must not less than 1. Oct 31, 2017 my colleague uses a programmable acdc hipot tester to 1 determine that a unit under test is truly connected to the hipot tester and 2 conduct a dc hipot test. Nrtls implement and enforce electrical safety testing to protect consumers from. Hipot testing has long been a standard procedure for assuring the electrical. A ground bond test would fail this test because the single wire would not be able. A record of the relative humidity near the equipment at the time of the test is also helpful. Measuaring motor insulation using hi pot tester 28012012 by lemau 1 comment when we need to evaluate the motor condition, hipot tester or high potential tester is the common equipment are used. Guidelines for high potential hipot dc testing of medium voltage. This equipment negates the need for onsite generation, large step down transformers or generating company supplies to be employed to power the items under test.
Such a test applies a voltage to the dut that is much higher than normal operating voltage. Designed to verify that the insulation of a product is. Testing of high voltage cables manual horizon power. Deviations from the baseline information permit evaluation of the insulation. The complete guide to electrical insulation testing. Vlf testing times should last between 15 and 60 minutes, depending on the age of the circuit and what type of test is conducted. The product contained two redundant patient connections. He programs the first step of the hipot tester sequence for 250 v, 60 hz. Designed to verify that the insulation of a product is adequate enough to withstand high voltage. Hipot testing procedure for withstand testing of hv coax. Hipot test is the most common type of electrical safety test. High voltage field acceptance test prior to being placed in service. Hipot test current, leakage current and insulation resistance.
Dc hipot test passfail analysis a dc hipot test is done at a voltage higher than the peak operating voltage of the device under test dut, where peak voltage rms voltage x 1. The test is sensitive to arcs or corona so it often finds terminal spacing problems, overmold problems, tolerance errors in idc cables, or any problem that might produce arcs. Guidelines for high potential hipot dc testing of medium. Apply high voltage to the insulation barrier of the dut and ensure there is no breakdown. In the boost or voltage withstand test process, as a result of short circuit, flashover, breakdown, such as over current, the current trip of relay protection, automatic voltage regulator power that test materials are not up to standard, at this time regulator should be back to. Safety guidelines for hipot testing and setting up a safe. A dielectric strength test, commonly called a hipot test, dielectric withstand, or high potential, is a stress test of the insulation of a device under test dut. Cableeye hvx system for high voltage cable and harness. Warning the 955i is intended to be powered from a power.
Insulationresistance test data may be used to establish a trending pattern. Hvx with cb29s, 128 test points, expandable external terminals for single channel safety test. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. However, the standards state that production hipot testing should not exceed 1,500vac, or its dcrectified equivalent of 2,121vdc, from input to output or input to ground. Acceptable procedures for conducting hipot testing, although varying slightly. A standard test for medical products is mains voltage to patient connection hipot. Performed by stressing the insulation of the product far.
The test can be done at various times such as acceptance of new cable installation, maintenance testing to track insulation degradation and as a pre and post test for splicing existing cables to new ones. As we know,a multimeter or ohm meter reading only can determine if a motor winding is open or shorted but cannot checked winding insulation condition. The dc hi pot leakage current technique, sometimes referred to as a megger test, involves the. Dec 14, 2011 what mental images do you have about testing cables with high voltages. If a user chooses to conduct this test, the cable ends will need to be cut. Understanding hi pot testing and its standards certifying a new product to relevant safety standards is an essential part of any design and development process.
As a result of setting limits for the hipot test, a medical device manufacturer was able to determine components within a product had changed. Therefore, if a test of an installed motor in a plant fails above peak operating voltage, it does not mean that. How to conduct a hipot test on a 11kv cable answer prabhu krishna. Test method is operating dut and under the status of all switches, link cables etc. For proof tests of new unused motors, the test voltages are as follows per ieee 95, iec and ansieasa ar100. Once the insulation is charged full test potential, the leakage current drops off to near zero ma. The test is usually performed at about 75% of the typical breakdown voltage and is done as a safety net. Also you should make tests at about the same temperature, or correct them to the same temperature. The following sections of the ansineta standard for acceptance testing specifications for. Understanding hipot certification testing electronic design. Standard for acceptance testing specifications for. Below are hipot test voltages for both dc hipot and ac hipot tests. Standard iec606011 covering medical equipment requires conduction testing at the higher voltage of. The small size and high power of the vlf tester helps to solve the practical problem of transmission loss during an ac test on very long sections of cable and apparatus in the field.
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