Simulate appropriate tests to evaluate the condition and perform maintenance on transformers. This method statement will give a brief steps to be carried out for testing and pre commissioning of 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. Manufacturers test thousands of distribution transformers at worldwide. Vector group test of transformerthe vector group of transformer is an essential property for successful parallel operation of transformers. Testing and commissioning procedure for electrical installation 1. It is not a complete stepbystep procedure for performing tests and is not replacing the user manual for the actual instrument. Connect the 120 v, 60 hz power through the lamp to the transformer. In addition to the above transformer testing methods, the power transformer also goes through some other tests, performed on it, before the actual commissioning of the transformer at the site. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2.
The standard megger testing equipment is used, the line terminal of which is connected to the winding or core bolt under test. Power transformer testing and commissioning guidelines r 1. Vector group test of power transformer electrical4u. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. Improve the quality control of the project and simplify the procedures for engineers.
The distribution utilities have generally been procuring transformers with maximum allowable. Perform oil sampling, testing, drying, filling and filtering. It rating plate show nominal voltage, current of the primary. This test reproduces conditions of continuous rated load and the temperature rise occurring during the load.
High voltage transformer distribution transformer all day efficiency of. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. Pdf transformer testing type test and routine test of. Insulation resistance tests megger test are carried out on all windings, core and core clamping bolts. The international electrical testing association neta is an accredited standards developer for the american national standards institute ansi. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers.
Power transformer testing and commissioning guidelines r. Noise measurements of the power transformers aleksandra petrovic1, ljubomir lukic1. 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. The charge transfer processes between capacitances ct and ck cause a residual voltage dropures. Transformer bushing cts should be tested using the current. Whether the transformers are used for wind, solar or hydro applications, actom distribution transformers can supply mineral oilfilled, cast resin dry type or environmentally friendly kclass ester oilfilled transformers. Transformer testing has developed considerably over the past years. Transformer testing commissioning, routine, diagnostic. Power transformer testing and commissioning guidelinesr sahoo procedure of power transformer testing and commissioning in transformer testing and commissioning, it can be classified into power and distribution transformers. Factory acceptance tests fat the routine tests shall be made with each electrical equipment and, whenever practicable. Inspect transformer and parts for shipping damage and moisture. Instructional video on distribution transformer testing.
The power partners commitment to manufacture quality distribution transformers is backed by a series of transformer tests used to verify conformance to. Test procedure for coppedfullwave on the tail impulse 12. In the uk this was, until january 1995, 415 v threephase and 240 v phase to neutral. Interpret nameplate data and use the data to set up correct test procedures. Distribution transformers can be shipped complete in standard shipping container. Neta is the leading source of specifications, procedures, testing, and requirements.
In any pd test circuit, the real measurable charge qm integral of the circulating pd current it, is dependent 80 ontheratioofcouplingcapacitancecktotestobjectcapacitancect,seefigure9. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of the transformer. Basics, maintenance, and diagnostics xi contents continued page 9. Analyze test results to troubleshoot transformer problems. The impulse test is one of several tests designed to verify the dielectric strength of the many insulation structures within the distribution transformer against line voltage surges. Mainly two types of transformer testing are done at manufacturer premises type test of. A free powerpoint ppt presentation displayed as a flash slide show on id. The international electrical testing association neta was formed in 1972 to establish uniform testing procedures for electrical equipment and apparatus.
The induced voltage on the low voltage side of the transformer is connected to the low voltage terminals of the ratio meter. Standard for acceptance testing specifications for. Testing manual for electrical equipment requirements are fulfilled. Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. It is performed to comply with ansi standards and for quality assurance. Some tests and procedures may be performed by specialists during the. Tamil nadu electricity board tneb, tamil nadu generation and distribution corporation limited tangedco, tamil nadu. When testing transformer windings with a very low impedance generally the low voltage side, it can be. We measure the induced voltages at hv and lv terminals of the transformer to find out actual voltage ratio of the transformer. Short circuit test and differential stability stable condition.
Selection guide abbs liquid filled power distribution transformers range from 16 kva upwards, with primary voltages up to 72. There are different methods for measuring of transformer winding, likewise. We repeat the test for all tap position separately. Download as ppt, pdf, txt or read online from scribd. Transformers are an electrical component that transmit electrical energy between at least two circuits. For conducting heat run test on the three phase transformer, full rated. 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. Neta defines the standards by which electrical equipment is deemed safe and reliable. Noise measurement of transformer 112 mva the test procedure is in accordance with iec standard 6007610. Power transformer testing fat test inspection for industry. Testing of power transformers seems like a similar experience.
The imposition of penalty is however subject to force majeure condition. Distribution transformers maintenance guide for liquid. Also the transformer is always to be switched to the maximum possible voltage during this test. Distribution transformer testing power partners usa. It is therefore most vital asset in any electrical distribution network and needs special attention right from erection, commissioning and maintenance of these transformers. The procedure of the transformer ratio test is simple. A primary part of commissioning a transformer involves testing it after its installation in the field. Stringent quality control has to be ensured right from selection of raw materials, manufacturing to procurement and installation of these transformers. Generator stepup auto transformer stepdown pads transformer transformer 11510 or 20 kv 500230 230. Theory heat run test is one of the type tests on power transformer. A list of standards applicable to distribution transformer is given as below. Abb supplies the widest range of power distribution transformers, including specific designs for power centres, substations, networks and padmounts. In this book we have laid down important aspects on transformer. Case 1 is only interconnecting cable between upstream and downstream panels, e.
To carry out the tests according to the standards and test procedures defined. Introduction the procedures stated in this document cover the activities in preliminary tests and inspections, functional performance tests and the commissioning of newly completed installations and existing ones after major alteration. Actom distribution transformers is the leader in the supply of transformers for the renewable energy sector. Transformer testing type tests and routine tests of. We just apply three phase 415 v supply to hv winding, with keeping lv winding open. Following is an approximate sequence for transformer testing. To fill in the test protocols, signing in the appropriate box. Before commencement of any test make sure the surroundings near clear off from any unwanted materials etc, and make proper approach, scaffolding etc. Distribution transformers 11 kv230 v and 11 kv central. 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 power transformer testing fat test is performed after completion of the assembly at the manufacturing shop. The high voltage winding of the transformer under test and the high voltage terminals of the ratio meter are connected to a low voltage single phase source. Neta developed specifications for the acceptance of new electrical apparatus prior to energization and for the maintenance of existing apparatus to determine its suitability to remain in service. What is the megger test procedure for transformers.
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