Hence, it demands special consideration during routine maintenance. This test also performed as a routine test of transformer. The accelerating voltage for a television cathode ray tube may be described as extrahigh voltage or extrahigh tension eht, compared to other voltage supplies within the equipment. Electrical routine testing of high voltage bushings. Testing of hv cables supplementary information page 1 of 24 reference sp0407r02 ver 2 ergon energy corporation limited abn 50 087 646 062 1. Power transformer testing procedures and schemes photo credit. Testing procedures for hv voltage transformers photo credit. Where high continuous currentcarrying capability is not required and where reclosing or sophisticated relay ing is not justifiedas is the case in the majority of transformer protection applications in mediumvoltage industrial, commercial, and institutional power systemspower fuses offer. Castcoil transformer a transformer with highvoltage coils cast in an epoxy resin. Greenlee is excited to expand the test and measurement portfolio with the hde high voltage line.
Maintenance of transformers a detailed checklist electrical4u. Power transformer testing swp check this is the latest process zone version before use. Optional perform an applied voltage test on all high and lowvoltage windingstoground. Nov 17, 2019 a power transformer requires various routine maintenance tasks including measurement and testing of different parameters of the transformer. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to. May 10, 20 this test also performed as a routine test of transformer. Testing procedures for hv voltage transformers include general inspection, insulation resistance, polarity and turns ration tests.
Ppt transformer tests powerpoint presentation free to. Air force technical document afapltr822057, volume 2, high voltage testing. Verify correct secondary voltage phasetophase and phasetoneutral after energization and prior to loading. Before conducting a transformer winding resistance test, it is important to observe all safety warnings and take proper precautions. Testing power transformers highvoltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. Almost all of them, ranging from power ratings from 20 mva to units well above 1,000 mva,and 20 kv to 1,100 kv are tailormade. William morse a free powerpoint ppt presentation displayed as a flash slide show on id. Hde brings a rich history of innovation, reliability and customer focus and will allow greenlee to offer a more complete product solution to power utility and electrical professionals. The accelerating voltage for a television cathode ray tube may be described as extra high voltage or extra high tension eht, compared to other voltage supplies within the equipment. The procedure of the transformer ratio test is simple. When ac hipot tests are used for routine maintenance, the power transformer can be examined at rated voltage for 3 min instead of testing at 65% of factory test voltage. Power transformer testing procedures and schemes eep.
Testing and diagnostic measurements on instrument transformers. Pdf high power, high voltage, high frequency transformer. Ac dielectric test for acceptance and routine maintenance for liquidfilled power transformers transformer. Page 2 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 sm0701. High voltage insulation testers for the power industry low voltage insulation testers for the electrical contractor insulation resistance testers above 2.
For more than a century, power suppliers and industrial companies have relied on siemens for its reliable and efficient power transformers. Optional perform an applied voltage test on all high and low voltage windingstoground. Ce mark to indicate thirdparty approved or selfcertification to specific requirements of the european community. C electrical power from one voltage to another voltage keeping the frequency same by electromagnetic induction discover the worlds research 17.
So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. A power transformer requires various routine maintenance tasks including measurement and testing of different parameters of the transformer. It is imperative to only compare a specimens pf values. Ensure that all equipment to be tested is properly grounded and treat all highvoltage power equipment as energized until proven otherwise by using the proper lockouttagout procedures. Apr 10, 2015 high vol tage testing of transformer by hari shankar singh 1. Check of phase displacement the polarity of singlephase transformers and connection symbol of threephase transformers shall be checked in each winding. There are two main types of maintenance of transformer. High voltage testing 149 the high voltage is applied across the device under test by means of a transformer. Morgan tm schaffer transformers the inside view transformer tests oil tests and online monitoring can increase transformer life expectancy by. Some utilities have started doing onsite high voltage testing using mobile test systems, and have reported positive results 1. Standard for acceptance testing specifications for. High voltage transformers are some of the most important and expensive pieces of equipment required for operating a power system.
In automotive engineering, high voltage is defined as voltage in range 30 to vac or 60 to 1500 vdc. This type of supply ranges from 5 kv to about 30 kv. Testing and diagnostic measurements on electric power equipment high voltage engineering, training and seminars. Because replacing a high voltage transformer requires planning for many reasons, including long manufacturing lead times that can exceed a full year, it is widely accepted that asset management, particularly of transformers, is a beneficial contribution to the operation of the grid. If a very high voltage is required, the transformer is usually build up in stages by cascading. The capacitors are connected between the system voltage and the polarity of a pt. 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. We perform one group on a routine basis known as preventative maintenance, and the second group on an adhoc basis i. Use megger mit1020 to measure insulation resistance. Power transformer oil sampling job safety analysis. Trafositetesting mobile highvoltage test system for onsite testing of power transformers flv english flv movie considerations for the design, manufacture, and retrofilling of power transformers with high fire point, biodegradable ester fluids english pdf technical publication.
To ensure sufficient clearance between the windings and between winding and earth. High voltage onsite power transformer testing ee publishers. Power transformers are subject to several electrical, mechanical, thermal, and environmental stresses during regular operation, with an expected life cycle of more than 30 years. Routine tests and type tests of transformers electrical4u. Testing of high voltage cables manual horizon power. As the pt secondary is normally grounded through an internal jumper, an external switch is often used to isolate the pt from ground during testing. Highly specialized for design of lvmv switchgears and lv high power busbar trunking power substations. The voltage ratio shall be measured on each tapping and verified aginst manufacturer approved power transformer testing procedure.
The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to the power system. High voltage testing requires larger power sources and on site generation and transformer equipment to produce the power and voltages required. We just apply three phase 415 v supply to hv winding, with keeping lv winding open. A potential transformer is a conventional transformer having primary and secondary windings. Ensure that all equipment to be tested is properly grounded and treat all high voltage power equipment as energized until proven otherwise by using the proper lockouttagout procedures. The main high voltage tests are included in type and routine tests made by the manufacturer in the factory to meet the required standards, quality and reliability. The ac hipot test values for voltages up to 69 kv are presented in table 1. To check the adequacy of main insulation to earth and between winding instruments. Cvts are often used in high voltage 115kv and higher applications and use a series of capacitors as a voltage divider. In addition to detecting problems associated with high resistance contacts and connectors, the megger winding tester will also detect open circuits dropout test. Basics, maintenance, and diagnostics vii contents continued page 4. It is typical the use of high voltage testing on transformers to confirm performance. Standard for acceptance testing specifications for electrical.
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