Transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer. In addition to that some transformer tests are also carried. Oct 11, 2015 introduction transformers are static alternating current machines principle is based on mutual induction between windings through a common core oilimmersed and dry types power and distribution types special types 6. In this book we have laid down important aspects on transformer. Inspect transformer and parts for shipping damage and moisture.
Transformer cant stepup or stepdown the level of dc voltage or dc current. Power transformer testing swp check this is the latest process zone version before use. The voltage ratio of a transformer is the ratio of the rms terminal voltage of a. Apr 16, 2018 transformer abnormal testing is required on safety isolation transformers to insure that the transformer output remains below hazardous voltage levels during fault conditions in the secondary circuit. Prior to testing, short the primary winding of the ct under test by connecting h1 and h2, then short the secondary winding of the ct under test by connecting x1 and x2x5.
All of these factors affect the amount of testing necessary to. Transformer testing type tests and routine tests of. Losses of transformersthe transformers are made of 2 types of materials. Useful for all types of loads including transformers. The potential transformer is mainly classified into two types, i. Diagnostic testing and monitoring of power transformers omicron. This type of transformer is categorized on the basis of a number of turns in. Potential transformers used primarily in a step down environment to monitor voltage. Different types of transformers and their applications. May 10, 20 transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer.
An electrical power transformer has to go through a number of transformer testing procedures for confirming its specifications and performances. All of these factors affect the amount of testing necessary to certify that a transformer is ready to be energized and placed in service. The core of a transformer is made of iron whereas thewinding which is wrapped over the iron core is made up ofcopper. When testing a transformer for turns ratio, the connections are determined by matching parallel vectors. Ratio testing with applied burden is the most accurate and complete approach for testing at ct in service. Transformers either increases or decreases ac voltage. Know the condition of your transformer to get the most out of your asset.
For confirming the specifications and performances of an electrical power transformer it has to go through numbers of testing procedures. The latest sfra test sets make these techniques more accessible, more convenient and. In this paper, the different types of transformer testing are mentioned. On subtractive polarity transformers the h1 primary lead and the x1 secondary lead will be on the same. Testing of power transformers seems like a similar experience. To prove that the transformer meets customers specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises. Transformers can be categorized in different ways, depending upon their purpose, use, construction etc. Transformer only stepup or stepdown the level of ac voltage or ac current. Instrument transformer testing instrument transformers for metering purposes must have a high degree of accuracy up to class 0. Commonly known as the megger test, insulation resistance testing measures the quality of insulation within the transformer. These are the most commonly used transformer types for all the applications. Onetoone transformer the transformers having k 1 i. Current transformer testing swp check this is the latest process zone version before use.
The results of the test series show how the breakdown voltage varies with the distance. Transformers, dry type, aircooled, lowvoltage, large. Transformer is one of the important equipment in power system. Remove the neutral ground and isolate the ct from any associated burden. Here we discuss different types of transformers are the step up and step down transformer, distribution transformer, potential transformer, power transformer, 1. The windings are shorted and the test voltage is applied to one winding while the. In this article, you will learn different types of transformer testing methods, test setup, and their acceptance criteria. Power transformer is an electric machine with a useful life cycle of some 30 years.
Insulation tests on current transformers rated 600v or less are usually performed at vdc. Polarity refers to the instantaneous direction of the primary current with respect to the secondary current and is determined by the way the transformer leads are brought out of the case. The various types of transformer shown in the figure above are explained in detail below. Portable precision current transformer testing ct pt analyzer. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf. The main function of such transformer is to provide isolation between input and output circuit, hence this transformer is also known as the isolation transformer. Electrical power transformer definition and types of. Type test and routine test of transformer electrical mastar. A transformer is an electrical device which, by the principles of electromagnetic induction, transfers electrical energy from one electric circuit to another, without changing the frequency. In addition to that some transformer tests are also carried out at the consumer site before commissioning. In such type of transformers output voltage is equal to the input voltage. Basics, maintenance, and diagnostics xi contents continued page 9. Worst case fault conditions are imposed at the output of the transformer shortcircuit conditions and separate overload conditions.
Sfra testing on transformers dismantling a power transformer to determine its condition is hardly ever a practical possibility. The transformer the principle parts of a transformer and their functions are. In addition to that some transformer tests are also carried out at the consumer site before commissioning and also periodically in regular and emergency basis through out its service life. This test is conducted to determine the iron losses or core losses and parameters r0 and x0 of the transformer. Equivalent circuit diagram for a transformer in noload. There are a multitude of checks and tests performed as a transformer is being assembled at a substation. The transformer has been built to standard damage has not been sustained during transit or installation. Page 3 of 9 standard work practice sp0507 ver 5 ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 rated knee point voltage 950 volts, maximum secondary winding resistance 3 ohms. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals. Mainly two types of transformer testing are done at manufacturer premises type test of transformer and routine test of transformer.
A presentation ontransformer testing using dpatt3bi 2. Read through the different types we supply below and use our instrument transformer rfq form to request a specific part to meet your requirements. Manufacturers name, manufacturers type description and manufacturers. So, testing the transformer is pretty serious issue.
Transformer operates when both circuits take effect of mutual induction. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062. The tests this laboratory is able to carry out are the. Note that sometimes these classifications overlap e. The energy transfer usually takes place with a change of voltage and current. Some transformer tests are also carried out at the consumer site before commissioning and also periodically in regular and emergency basis throughout its service life. The core, which makes a path for the magnetic flux. Tests types and test laboratory capacity the test laboratory of asea brown boveri, s. The primary coil, which receives energy from the ac source. A variety of types of electrical transformer are made for different purposes. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. It is also done at site to ensure healthiness of a transformer that is to check loose connections, broken strands of conductor, high contact resistance in tap changers, high. Following is an approximate sequence for transformer testing. Routine tests and type tests of transformers electrical4u.
It is carried out as a type test as well as routine test. Portable ct pt analyzertransformer testgfuve electronics. Transformer turns ratio test sets come in a variety of styles and test connections, however all turns ratio testers have at least two high leads and two low leads. Transformers explaining the basics of transformers. Types of electrical transformer tests the balance small. Field testing of a power transformer before putting into service 50mva.
Sep 26, 2017 mainly two types of transformer testing are done at manufacturer premisestype test of transformer and routine test of transformer. Unlike the tests described previously, in the present case nominal voltage is applied. Ct ratio with burden testing secondary connection is made through the test switch same connection that is used for the rest of the site testing. Types of transformer different types of transformer. The secondary coil, which receives energy from the primary winding and delivers it to the load. Nov 15, 2019 a current transformer is an instrument transformer, used along with measuring or protective devices, in which the secondary current is proportional to the primary current under normal conditions of operation and differs from it by an angle which is approximately zero. Theory says that this kind of furanic derivates is never present in oil in. Feb 08, 2015 mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. They are designed for connection linetoline or linetoneutral in the same manner as ordinary voltmeters. To understand the nature of ratio testing it is important to understand the applicable definitions.
Here the important thing to remember is that there will not be any difference in primary power and secondary power. Some variations in testing results in natural, depending on the moisture, cleanliness and the temperature of the insulation, but to pass, the insulation must. Understanding transformer abnormal testing certifigroup. These are widely used transformer types for all the applications. Transformer testing has developed considerably over the past years. Testing is typically done with a megohmmeter, a tool similar to a multimeter but with a much higher capacity. By using the latest proven sfra test techniques, it is possible to accurately assess transformer condition without dismantling it. Size and kva rating also dictate the kind and number of auxiliary devices a transformer will require. The potential transformer may be defined as an instrument transformer used for the transformation of voltage from a higher value to the lower value. Transformer winding resistance measurement is carried out to calculate the i 2 r losses and to calculate winding temperature at the end of a temperature rise test. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2.
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