Insulation resistance tests megger test are carried out on all windings, core and core clamping bolts. Distribution transformers 11 kv230 v and 11 kv central. Transformer testing has developed considerably over the past years. Standard for acceptance testing specifications for.
Vector group test of transformerthe vector group of transformer is an essential property for successful parallel operation of transformers. Noise measurement of transformer 112 mva the test procedure is in accordance with iec standard 6007610. Before commencement of any test make sure the surroundings near clear off from any unwanted materials etc, and make proper approach, scaffolding etc. The distribution utilities have generally been procuring transformers with maximum allowable. Selection guide abbs liquid filled power distribution transformers range from 16 kva upwards, with primary voltages up to 72. 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. To fill in the test protocols, signing in the appropriate box. Some tests and procedures may be performed by specialists during the. Distribution transformers can be shipped complete in standard shipping container. Stringent quality control has to be ensured right from selection of raw materials, manufacturing to procurement and installation of these transformers. Perform oil sampling, testing, drying, filling and filtering.
Following is an approximate sequence for transformer testing. Distribution transformers maintenance guide for liquid. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. Short circuit test and differential stability stable condition. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of the transformer. Interpret nameplate data and use the data to set up correct test procedures. The induced voltage on the low voltage side of the transformer is connected to the low voltage terminals of the ratio meter. The power partners commitment to manufacture quality distribution transformers is backed by a series of transformer tests used to verify conformance to. Power transformer testing and commissioning guidelines r 1. A list of standards applicable to distribution transformer is given as below.
Inspect transformer and parts for shipping damage and moisture. In this book we have laid down important aspects on transformer. Connect the 120 v, 60 hz power through the lamp to the transformer. We just apply three phase 415 v supply to hv winding, with keeping lv winding open. The standard megger testing equipment is used, the line terminal of which is connected to the winding or core bolt under test. Noise measurements of the power transformers aleksandra petrovic1, ljubomir lukic1. 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. Transformers are an electrical component that transmit electrical energy between at least two circuits. The charge transfer processes between capacitances ct and ck cause a residual voltage dropures. The power transformer testing fat test is performed after completion of the assembly at the manufacturing shop. Transformer bushing cts should be tested using the current. The international electrical testing association neta was formed in 1972 to establish uniform testing procedures for electrical equipment and apparatus.
Actom distribution transformers is the leader in the supply of transformers for the renewable energy sector. Transformer testing type tests and routine tests of. Manufacturers test thousands of distribution transformers at worldwide. 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. High voltage transformer distribution transformer all day efficiency of. Transformer testing commissioning, routine, diagnostic. Power transformer testing fat test inspection for industry. Factory acceptance tests fat the routine tests shall be made with each electrical equipment and, whenever practicable. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. Before conducting a transformer winding resistance test, it is important to observe all safety warnings and take proper precautions.
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. Theory heat run test is one of the type tests on power transformer. This method statement will give a brief steps to be carried out for testing and pre commissioning of transformers. 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. Download as ppt, pdf, txt or read online from scribd. Test procedure for coppedfullwave on the tail impulse 12. A free powerpoint ppt presentation displayed as a flash slide show on id.
What is the megger test procedure for transformers. Tamil nadu electricity board tneb, tamil nadu generation and distribution corporation limited tangedco, tamil nadu. This test reproduces conditions of continuous rated load and the temperature rise occurring during the load. Testing and commissioning procedure for electrical installation 1. Power transformer testing and commissioning guidelines r. Simulate appropriate tests to evaluate the condition and perform maintenance on transformers. 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. The imposition of penalty is however subject to force majeure condition. Analyze test results to troubleshoot transformer problems. Generator stepup auto transformer stepdown pads transformer transformer 11510 or 20 kv 500230 230.
Also the transformer is always to be switched to the maximum possible voltage during this test. This amounts to a rigorous examination of the transformer intended to. Improve the quality control of the project and simplify the procedures for engineers. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers. Neta defines the standards by which electrical equipment is deemed safe and reliable. When testing transformer windings with a very low impedance generally the low voltage side, it can be. A primary part of commissioning a transformer involves testing it after its installation in the field. To carry out the tests according to the standards and test procedures defined. Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. Testing of power transformers seems like a similar experience. It is performed to comply with ansi standards and for quality assurance. In any pd test circuit, the real measurable charge qm integral of the circulating pd current it, is dependent 80 ontheratioofcouplingcapacitancecktotestobjectcapacitancect,seefigure9. Vector group test of power transformer electrical4u.
The procedure of the transformer ratio test is simple. It rating plate show nominal voltage, current of the primary. The international electrical testing association neta is an accredited standards developer for the american national standards institute ansi. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. It is therefore most vital asset in any electrical distribution network and needs special attention right from erection, commissioning and maintenance of these transformers. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2. Pdf transformer testing type test and routine test of. 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. There are different methods for measuring of transformer winding, likewise. 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.
There are various test required on transformer to conform performance of transformer. 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 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. In the uk this was, until january 1995, 415 v threephase and 240 v phase to neutral. The connection arrangement for a kick test for a current transformer is presented in figure 3. It is not a complete stepbystep procedure for performing tests and is not replacing the user manual for the actual instrument. Mainly two types of transformer testing are done at manufacturer premises type test of. Neta is the leading source of specifications, procedures, testing, and requirements. Distribution transformer testing power partners usa. We measure the induced voltages at hv and lv terminals of the transformer to find out actual voltage ratio of the transformer. 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. Instructional video on distribution transformer testing.