These types of transformers are used in electric power transmission and also in appliances to supply the low voltage. Testing transformer3 easy methods to test transformers. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. The transformer the principle parts of a transformer and their functions are. These devices use standard transformer theory with 23 windings one primary with one or two secondary windings with a magnetic connection via an iron core.
In this transformer the voltage is stepped down at the secondary from high voltage primary so that it is called as stepdown transformer. The primary coil, which receives energy from the ac source. How to use an ohmmeter to test an ac transformer sciencing. Electrical power transformer definition and types of. In this paper, the different types of transformer testing are mentioned. Unlike the tests described previously, in the present case nominal voltage is applied. The secondary coil, which receives energy from the primary winding and delivers it to the load. Instrument transformers for metering purposes must have a high degree of accuracy up to class 0. Core type transformer in the core type transformer magnetic core is made from l shape strips. Measurement of impedance voltageshort circuit impedance and load loss short circuit test. The usual procedure is for the person operating the battery connections to. In this article im only explain on how to test the linear transformer. We have broken them up into several different groupings. Type test and routine test of transformer electrical mastar.
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. There are various test required on transformer to conform performance of transformer. Depending on the type of the transformer, the input and output. According to the design, transformers can be classified into two. Transformers explaining the basics of transformers. In comparison to the impulse procedure, sfra is preferred for frequency domain. Type test are conducted on a transformer which is a representative of other transformers. Quick and easy threephase testing of power transformers. Transformer types instrument transformers instrument transformers comprise a large category of current and potential transformers for various voltage, frequency and physical size ranges. The transformer has been built to standard damage has not been sustained during transit or installation. Here we discuss different types of transformers are the step up and step down transformer, distribution transformer, potential transformer, power transformer, 1. On subtractive polarity transformers the h1 primary lead and the x1 secondary lead will be on the same.
Transformers can be categorized in different ways, depending upon their purpose, use, construction etc. All materials and relevant documentation to this testing works shall be checked by the responsible personnel prior to the commencement of testing activities. T m 5686 headquarters departmen t o f th e army washington, dc, 16 novembe r 1998 approved for public release. In addition to that some transformer tests are also carried out at the consumer site before commissioning. Basics, maintenance, and diagnostics xi contents continued page 9. Tests types and test laboratory capacity the test laboratory of asea brown boveri, s. Ratio testing with applied burden is the most accurate and complete approach for testing at ct in service. Transformers are an electrical component that transmit electrical energy between at least two circuits.
The test items mainly include excitation characteristic, transformation. This will prevent inaccurate readings and ensure your own safety. Measurement of impedance voltageshort circuit impedance principal tap and load loss short circuit test measurement of noload loss and current open circuit test. 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.
The voltage ratio of a transformer is the ratio of the rms terminal voltage of a. Transformer testing techniques electrical engineering portal. Pdf transformer testing type test and routine test of. Transformer testing allows this aging process to be quantified and tracked, to help predict replacement intervals and avoid failures.
Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. In addition some other tests are also carried out by the consumer at site before commissioning and also. Transformer testing preliminay test carried out on transformer before it is put into the tank. If the primary current changes, the secondary current output will change accordingly. Transformers either increases or decreases ac voltage. 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. Types of transformer different types of transformer. Power transformer testing swp check this is the latest process zone version before use. 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. Some tests are done at manufacturer premises before delivering the transformer. This test ensures that the transformer will provide the proper stepup or step down in voltage.
The tests this laboratory is able to carry out are the. Potential transformers pts or voltage transformers vts pts or vts are the most common device used. Type test of transformer confirms main and basic design criteria of a production lot. Testing of power transformers seems like a similar experience. Routine tests and type tests of transformers electrical4u. Mainly two types of transformer testing are done at manufacturer premises type test of transformer and routine test of transformer. By using the latest proven sfra test techniques, it is possible to accurately assess transformer condition without dismantling it. Quick and easy threephase testing of power transformers november 18, 2016 with testrano 600, omicron has developed the worlds first portable, threephase test system, which supports all common electrical tests on power transformers. Transformer testing has developed considerably over the past years. Ct ratio is described as the ratio of primary current input to secondary current output at full load. All of these factors affect the amount of testing necessary to certify that a transformer is ready to be energized and placed. Repeat the test for the other phases and the other secondary cores.
The core, which makes a path for the magnetic flux. Measurement of no load loss and current open circuit test. Jun 01, 2015 these are most commonly used transformers and are available from milliwatts to megawatts range. It is mainly used for field testing of p class ct and pt. To test a transformer, however, you will need to disconnect it from the circuit before doing anything else. In such type of transformers output voltage is equal to the input voltage. Iribution is unlimited power transformer maintenance and acceptance testing. Tm 5686 power transformer maintenance and acceptance. Different types of transformers and their applications. Mainly two types of transformer testing are done at manufacturer premisestype test of transformer and routine test of transformer. Transformers experience power loss due to load resistance, which you can test with an ohmmeter by touching the meters red and black pins to opposite ends of the transformer s wiring. This transformer consists of a laminated core to reduce the eddy currents. For confirming the specifications and performances of an electrical power transformer it has to go through numbers of testing procedures. Portable ct pt analyzertransformer testgfuve electronics.
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. These are most commonly used transformers and are available from milliwatts to megawatts range. 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. To understand the nature of ratio testing it is important to understand the applicable definitions.
Transformer is one of the important equipment in power system. May 10, 20 transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer. Generally there are two types of transformer in the market i. Historical test data is valuable for determining damage to the transformer after a fault or failure has occurred elsewhere in the circuit. Portable precision current transformer testing ct pt analyzer. The voltage induced in different phases of transformer in respect to neutral. The transformer turns ratio test is used to make sure that the ratio between the windings of the primary and secondary coils follow the proper specifications.
It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. The various types of transformer shown in the figure above are explained in the detail below. Magnetization and primary injection test of current. This test is conducted to determine the iron losses or core losses and parameters r0 and x0 of the transformer. Worst case fault conditions are imposed at the output of the transformer shortcircuit conditions and separate overload conditions. Magnetization and primary injection test of current transformer for protective relaying jacob tsado 8 current transformers. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50. Connection on cpc100 will be same as the shown figure. 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. In this book we have laid down important aspects on transformer. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf.
Sfra testing on transformers dismantling a power transformer to determine its condition is hardly ever a practical possibility. The procedure of the transformer ratio test is simple. The latest sfra test sets make these techniques more accessible, more convenient and. There are different methods for measuring of the transformer winding, likewise.
There are several transformer types used in the electrical power system for different purposes, like in power generation, distribution and transmission and utilization of electrical power. Transformer testing type tests and routine tests of. Current transformer testing swp check this is the latest process zone version before use. Note that sometimes these classifications overlap e. Fat or acceptance test or witness test or joint inspection test is. Testing transformer is very easy if you follow the procedure explained in this article. Just be certain to disconnect the transformer from the circuit before testing to avoid the risk of serious injury. Put your ohmmeter on its lowest scale and after removing the plastic sheaths from the conductors, touch its leads together to verify that it is ready for testing.
So, testing the transformer is pretty serious issue. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals. Various types of probes can be used for primary side. There are three basic styles used to transformer system voltages to control voltages. Understanding transformer abnormal testing certifigroup. Each transformer asset manager must select the amount and type of.
Nov 18, 2016 quick and easy threephase testing of power transformers november 18, 2016 with testrano 600, omicron has developed the worlds first portable, threephase test system, which supports all common electrical tests on power transformers. There are a multitude of checks and tests performed as a transformer is being assembled at a substation. Home products transformer testportable ct pt analyzer. The transformers are classified based on voltage levels, core medium used, winding arrangements, use and installation place, etc. The core type transformer consists of an iron core surrounded by windings. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062. Onetoone transformer the transformers having k 1 i. On the basis of core and winding arrangement, following are the main types of transformers.
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. Transformers regulate the voltage in circuits, but in some cases these. The energy transfer usually takes place with a change of voltage and current. Here the important thing to remember is that there will not be any difference in primary power and secondary power. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by michael faraday, and share several key functional parts. Transformer basicsworking principle,construction,types. Measurement of noload loss and current open circuit test measurement of insulation resistance. In power plant this transformer is used as connecting transformer of generator to grid. Transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer.
In this test, the rated voltage is applied to the primary usually lowv. Also when a transformer is rewound with different primary and. Pdf transformer is a static device which transforms a. Testing will commence only after the equipment is completely installed as per approved method statement for the installation of the transformer and released for testing commissioning. These are the most commonly used transformer types for all the applications.
While testing, basic testing requirements and testing codes are set out in the national and international standards. Cts are instrument transformers used for converting primary current into a reduced secondary current for use with meters, relays, control equipment and other instruments. Mainly two types of transformer testing are done at manufacturer premises type. Instrument transformer theory and testing steve hudson, pe engineering manager 10737 lexington drive knoxville, tn 37932. Measurement of impedance voltageshort circuit impedance principal tap and load loss short circuit test. In coretype transformer, the windings are given to a considerable part of the core.