While doing the hv test the steps to be followed are as below. High voltage cable splicing and cable termination techniques final, by david e. For single conductor nonshielded cable on a reel, insulation resistance testing cannot be performed due to the fact that low voltage single conductors do not have a grounding conductor, shield or ground plane. The choice of testing techniques and procedures for medium voltage cables is now well defined and enables the implementation of effective plans for the proving cable fitness for service. When comparing this figure to power frequency ac or 0. P53 high voltage isolation and access procedures prior to gaining access to hv cable. A stitch in time 5 once started, the different enemies tend to aid each other, permitting excessive current through the insulation. Typically, the applied test voltage is raised in steps, with measurements first taken up to 1uo, or normal line to ground operating voltage. Vlf cable test voltage ieee standard high voltage inc. This publication is a collection of items of general information related to the subject of power cable.
What is the permissible leakage current value for a 11kv cable. Medium voltage soft starters will have their starting and stopping functionality demonstrated by starting and. Aug 27, 2012 alfanar testing and commissioning 33,176 views 3. Tests using multivoltage megger insulation testers 42. Typical factory test procedures for medium voltage products. Medium voltage switchgear ax1 is described in many different publications and even in a.
Testing insulated conductors use a proximity tester for a first test should not be used as the only test if no voltage indicated wearing ppe, expose conductor for testing verify 0 volts with contact meter voltage indicated with proximity tester verify proper circuit is locked out recheck source for induced voltage using a high. This technical article provides general guidelines for high potential hi pot dc testing of mv power cables. Visual inspection is recommended for all incoming material as cable could be damaged during shipment and delivery. For other cable on a reel, insulation resistance testing can be performed provided the sealing caps are removed. Acceptance and maintenance testing of medium voltage power. The complete guide to electrical insulation testing. For this reason, it is common practice to cut off a portion of cable after pulling to assure an undamaged end. Method statement for installation of high voltage hv. Field testing of mediumvoltage cables cable degradation and diagnostic tests. Various cable testing practices are covered in the following documentation. Insulation resistance testing is a nondestructive test procedure. The medium voltage switchgear ax1 is not just a medium voltage cubicle, but also a complete switchgear systeminstallation. Vlf cable test voltages and time durations are set by ieee standard 400. Individually test each conductor with all other conductors and shields grounded.
Technical note voltage cable splicing and cable termination. Cable installation manual for power and control cables ninth edition, september 2011 2. Perform a shieldcontinuity test on each power cable. If there any formula for calculating leakage current, cable rated voltage 8. Embedded cable testing compartment, easy and safe cable testing without cable connection removal. Manual installation commissioning environment and recycling. The manufacturers and nonnuclearpower users of medium voltage cable have since recognized that cables manufactured. Selection of the protection system and relays depends on and is correlated with the plant characteristics, type of industrial process and its service continuity requirements, with the status of the neutral, characteristics of the machines, levels and duration of the fault currents, etc. Any one please explain the hi pot pressure test testing procedure for 3 core 70 sq.
Apply voltage in accordance with manufacturers published data. Designed to verify that the insulation of a product is adequate enough to withstand high voltage. 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. Maintenance free unit offering a life expectation of over 30 years. Perform a shieldcontinuity test on each power cable by ohmmeter method. Medium high voltage cable preparation it is necessary to begin with a good cable end. Acceptable procedures for conducting hipot testing, although varying slightly in technique, have been standardized as either a withstand test or a timeleaking current test. Nov 08, 2015 field testing of medium voltage cables cable degradation and diagnostic tests. A key to good cable preparation is the use of sharp, high quality tools. Typical factory test procedures for medium voltage products 3.
Dac voltage testing is one of the alternative methods of ac voltage testing and is applicable for a broad range of mediumvoltage, highvoltage, and extrahighvoltage cables. It is important to recognize that many factors must be considered to properly characterize the test results obtained from any cable testing program. It is not intended to be nor should it be used as authority for design, construction, or use of power cable. A new set of well conceived testing standards has been developed in response to changes in cable technology in recent years. These numbers result from many years of vlf field use and research. Perform an insulationresistance test utilizing a megohmmeter with a voltage output of at least 2500 volts. Guidelines for high potential hipot dc testing of medium. Request startup documentation from the startup engineer level 3 testing acceptance testing documentation is often accepted as level 3 testing in this situation as long as there isnt a control system involved see medium voltage and complex electrical systems use the startup documentation, submittal, and opr to. Medium voltage cables used in nuclear power plants were expected to have very long lives, at least the 40 years of the initial licensed period. Single and three core medium voltage cables according to international standard iec 60502 1. Dc high voltage testing of new xlpe cables is not recognised to cause cable deterioration, however in order to adopt a standard approach vlf ac testing is preferred instead of dc high voltage testing for new and aged xlpe cables. When the various layers are removed, cuts should extend only partially. This method statement defines the procedure step by step to implement the correct practices for installation of high voltage hv cable in order to ensure that the job execution complies with the project requirements and serves the intended function to satisfactory level. Figure f2 cable feed into conduit at floor level c from cable reel to cable tray, the cable is fed from the top of the reel to maintain required curvature.
Ieee std 400 provides additional information on dc testing and evaluation of the insulation of shielded power cable systems c. The voltage of the cable must be chosen according to the maximum voltage um in. This testing of high voltage hv cables manual has been developed for use by. Sometimes the drop in insulation resistance is sudden, as when equipment. Electrical utility field testing for mediumvoltage cables. Vlf hipots are also widely used for testing newly installed andor repaired cable before reenergizing to insure the cable is.
Dc leakage currents tell little about the cable quality. The current method of testing circuit breakers 05152011one of the most critical devices on any electricity network is the circuit breaker which can be described as the silent sentinel, standing guard over the network and only being called into action when. Commissioning tests for hv cables up to 33kv swp ergon energy. If the tan delta numbers indicate good cable insulation, the test voltage is raised up to 1. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. For doing r phase the other phases are shorted and earthed.
All tests made following cable installation and during the warranty period must be performed in accordance with the applicable specifications. Damped alternating current voltages are generated by charging the test object to a predetermined voltage level and then discharging its capacitance through a suitable inductance. Mediumhigh voltage cable preparation it is necessary to begin with a good cable end. It is important when operating on medium voltage equipment that we follow the safety rules and operating regulations in order to be safe.
Smart interlocking padlocking system for maximum operator safety. Megger guide to electrical insulation testing pdf instrumart. This paper covers general safe operations on medium voltage equipment and looks at the aspects of switching, isolating, testing and earthing, as well as various types of medium voltage testers and their usage. The dielectric voltagewithstand test is commonly known as the hipot test. Hundreds of standards including cable testing standards. This overview is provided as an insight into understanding of the nature of inservice cable degradation and some of the more commonly used diagnostic techniques commercially available for performing tests in the field on extruded, mediumvoltage, shielded power cables. Rated 5 kv and above with high direct current voltage. High quality tank welding, leakage rate of less than 0.
In the absence of manufacturers published data, use table 100. Standard for acceptance testing specifications for electrical. Netas 2010 outstanding acheievement award honoring netas most valuable asset. During cable pulling, cable is sometimes subjected to physical stress due to excessive force exerted on it that could eventually leads to damaging the outer layer parts that serve as primary protection of the cable. Electrical utility field testing for medium voltage cables this document outlines the various methods for field testing medium voltage cable either during or after installation. Weems tn1452 20 pp illus august 1976 unclassified 1. Ieee guide for field testing of laminated dielectric, shielded power cable systems rated 5 kv and above with high direct current voltage. Several builtin interlocks and safety features are provided. Full clockwise rotation to min minimum connect the high voltage test cable to the ac out u post and the ground test cable is connected to ground g post as shown in illustration b. Medium voltage products technical guide protection. Electrical utility field testing for mediumvoltage cables this document outlines the various methods for field testing mediumvoltage cable either during or after installation. Standard for acceptance testing specifications for.
The choice of testing techniques and procedures for medium voltage cables is now well defined and enables the implementation of. 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 test measures the insulation resistance between the phases andor between phase and ground. The values associated with the testing methods shall be in accordance with the applicable table 100. This overview is provided as an insight into understanding of the nature of inservice cable degradation and some of the more commonly used diagnostic techniques commercially available for performing tests in the field on extruded, medium voltage, shielded power cables.
The construction of the 515 kv type vaccladw metalclad switchgear allows for the placement of circuit breakers in the upper or. Medium voltage products technical guide protection criteria. Example of asbestos paper insulation wrap on highvoltage cable inside an underground cable vault. Compare bolted connection resistances to values of similar connections. From a definition point of view ax1 is a primary encapsulated and air insulated switchgear. In accordance with icea, iec, ieee and other power cable consensus standards, testing. 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. Applying voltage to the equipment and connecting to a test motor in the mv test facility. A typical 15 kv medium voltage cable in usa has an insulation thickness of 0.
The above information describes vlf withstand testing, where the intent of the test is to apply a sufficient test voltage for a long enough time to. Performed by stressing the insulation of the product far beyond what it would encounter during normal use. Medium voltage operation mv drives and soft starters are temporarily installed in the mv test bay and operated on an mv dynamometer. Calculation procedure 19 installation in cable tray 20 rollers and sheaves 20. The choice of testing techniques and procedures for medium voltage cables is now. Hipot test is the most common type of electrical safety test. Testing of hv cables supplementary information page 1 of 24 reference sp0407r02 ver 2 ergon energy corporation limited abn 50 087 646 062 1. Instructions for installation, operation, and maintenance.
Euromold provides a complete range of accessories for underground cables. This means that all high voltage parts are housed in the encapsulated main circuit enclosure and are inaccessible from the outside. Testing of high voltage cables manual horizon power. The procedure to test these cables is outlined below. Method statement for installation of high voltage hv cables. Vlf cable testing very low frequency is a technique for testing of medium and high voltage mv and hv cables. The cable tests described below are to be carried out after.
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