Distribution transformers maintenance guide for liquid. Basics, maintenance, and diagnostics xi contents continued page 9. Insulation resistance tests megger test are carried out on all windings, core and core clamping bolts. Functional specification for threephase padmounted. The transformer must be deenergized before this procedure, unless it. The connection arrangement for a kick test for a current transformer is presented in figure 3. Connect the 120 v, 60 hz power through the lamp to the transformer. The transformer shall be designed in accordance with this specification and the kva. The checklists are in pdf format and can be completed electronically or printed and used as hard copy. Oil filled power transformers, regulators, and reactors 2. A list of standards applicable to distribution transformer is given as below.
Manufacturers test thousands of distribution transformers at worldwide locations each week. Transformer testing has developed considerably over the past years. As it checks the quality of material used and the procedure of transformer manufacturing hence provide us details of life of transformer, the transformer behaviour on different faults. In the uk this was, until january 1995, 415 v threephase and 240 v phase to neutral. Conservation standards for distribution transformers.
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. Distribution transformer testing power partners usa. Test code for liquidimmersed distribution, power, and regulating transformers 1 and ieee std 621995 to be changed to c57. Distribution transformers are normally considered to be those transformers which provide the transformation from 11 kv and lower voltages down to the level of the final distribution network. Due to transport limitation and for convenience of storagehandling at site, if a unit can be dispatched completely assembled then the transformer is usually dispatched from the factory with. The procedure of the transformer ratio test is simple. This amounts to a rigorous examination of the transformer intended to. Vector group test of power transformer electrical4u. In this paper testing of distribution transformer is considered. Simulate appropriate tests to evaluate the condition and perform maintenance on transformers. This practical commissioning test was developed decades ago and the authors are simply presenting the theory and procedure of how the test performs in the.
Power transformer testing fat test inspection for industry. It is therefore most vital asset in any electrical distribution network and needs special attention right from erection, commissioning and maintenance of these transformers. Ansineta standard for acceptance testing specifications for electrical power equipment and systems, 2009. Transformer installation, operation, and maintenance manual.
Noise measurement of transformer 112 mva the test procedure is in accordance with iec standard 6007610. In this book we have laid down important aspects on transformer. It is not a complete stepbystep procedure for performing tests and is not replacing the user manual for the actual instrument. For distribution transformers, the magnitude of the short circuit current, the numbers of shortcircuit tests and the duration of each short circuit test. Before commencement of any test make sure the surroundings near clear off from any unwanted materials etc, and make proper approach, scaffolding etc. The power partners commitment to manufacture quality distribution transformers is backed by a series of transformer tests used to verify conformance to. To carry out the tests according to the standards and test procedures defined. Testing of any electrical equipment indicates the extent to which the equipment is able to comply with a customers requirements. A primary part of commissioning a transformer involves testing it after its installation in the field. Noise measurements of the power transformers aleksandra petrovic1, ljubomir lukic1. For conducting heat run test on the three phase transformer, full rated.
Transformer testing winding resistance test as per indian standard manoj bhalerao. Hence every electrical power transformer must undergo through vector group test of transformer at factory site for ensuring the customer specified vector group of transformer. Selection guide abbs liquid filled power distribution transformers range from 16 kva upwards, with primary voltages up to 72. This test also performed as a routine test of transformer. As such, in this paper, a detailed procedure of the throughfault test for power transformer differential circuit prior to substation energization using the practical examples is covered. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to.
Pdf transformer testing type test and routine test of. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers. To fill in the test protocols, signing in the appropriate box. Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. Generator stepup auto transformer stepdown pads transformer transformer 11510 or 20 kv 500230 230. Transformers should be carefully inspected upon receipt. A free powerpoint ppt presentation displayed as a flash slide show on id. The type and routine test are very important for transformer. Before conducting a transformer winding resistance test, it is important to observe all safety warnings and take proper precautions. Neta developed specifications for the acceptance of. Magnetic balance and magnetising excitation current test a effective diagnostic tool. The power transformer testing fat test is performed after completion of the assembly at the manufacturing shop.
Electrical inspection checklists this pdf contains 77 electrical inspection checklists taken from the 2014 electrical inspection manual with checklists. Transformer testing type tests and routine tests of. A thermo vision camera determines the temperature distribution. Shortcircuit testing of distribution and power transformers. The standard megger testing equipment is used, the line terminal of which is connected to the winding or core bolt under test. Interpret nameplate data and use the data to set up correct test procedures.
So transformer ratio test is an essential type test of transformer. Functional specification for threephase padmounted distribution transformers 4510,000 kva pdf. Testing power transformers highvoltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. Actom distribution transformers designs and manufactures a wide range of distribution transformers. Thus by suitable testing procedure we must ensure that this is done. The distribution utilities have generally been procuring transformers with maximum allowable. Actom distribution transformers actom distribution transformers plays a vital role in the electrical distribution chain. Does existing test procedure for distribution transformers appears at 10 cfr 431. Abb supplies the widest range of power distribution transformers, including specific designs for power centres, substations, networks and padmounts.
Transformer testing winding resistance test as per. Following is an approximate sequence for transformer testing. Stringent quality control has to be ensured right from selection of raw materials, manufacturing to procurement and installation of these transformers. As power transformer is highly expensive as well as important part of distribution system. Neta is not only for commissioning new equipment but for testing the reliability and performance of existing equipment. Testing of power transformers seems like a similar experience. This method statement will give a brief steps to be carried out for testing and pre commissioning of transformers. Distribution transformers can be shipped complete in standard shipping container.
Vector group test of transformerthe vector group of transformer is an essential property for successful parallel operation of transformers. The information contained herein may not cover all variations in equipment or provide for all contingencies. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to the power system. Transformers are an electrical component that transmit electrical energy between at least two circuits.
Distribution transformers 11 kv230 v and 11 kv central. Perform oil sampling, testing, drying, filling and filtering. Power factor testing of power and distribution transformers. They provide the link between the distribution network and customers, be they industries, communities or the infrastructure. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the vital tests. An electrical power transformer has to go through a number of transformer testing procedures for confirming its specifications and performances.
What is the megger test procedure for transformers. Theory heat run test is one of the type tests on power transformer. Transformer testing commissioning, routine, diagnostic. This guide explains the many types of transformer and the power factor test procedures for each one. Vacuum cast coil dry type distribution transformers. This test reproduces conditions of continuous rated load and the temperature rise occurring during the load. In this article, you will learn different types of transformer testing methods, test setup, and their acceptance criteria.
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