Product type transformer protection ied type ret670 v2. Metering vs protection classes january 19, 2016 page. Type tests are done mainly in a prototype unit not in all manufactured units in a lot. Power transformer short circuit type test electric power. Guidelines to power transformer type, routine and special tests eep. Basics, maintenance, and diagnostics vii contents continued page 4. Type test of transformer confirms the main and basic design criteria of a production lot. Transformers, dry type, aircooled, lowvoltage, large.
Dry type transformer testing introduction the primary concern with all transformers and also the key indicator of life expectancy is the condition of the insulation system. The secondary coil, which receives energy from the primary winding and delivers it to the load. The methods used during tests and measurements of the power transformers, test and measurement circuits, calculations and evaluation criterias are included in this manual. There is no electrical connection between the coils, they are connected to each other through magnetic flux. The procedure of the transformer ratio test is simple.
Transformer tests eep electrical engineering portal. Condition of the test transformer regarding its temperature, oil level, tap position and mechanical appearance. Wound cts have a primary and secondary winding like a normal transformer. Power transformer type, routine and special tests include measurement of. Engineer samples for test and it will be modified if the test failure. Turnsratio test results should not deviate more than onehalf percent from either the adjacent coils or the calculated ratio. Routine tests and type tests of transformers electrical4u. Measurement of impedance voltageshort circuit impedance principal tap and load loss short circuit test measurement of noload loss and current open circuit test. Unless otherwise specified, the following type tests, when required, shall be performed on one transformer for each constructional tipology. The primary coil, which receives energy from the ac source. Sep 26, 2017 oil pressure test on transformer to check against leakages past joints and gaskets. In this transformer the voltage is stepped down at the secondary from high voltage primary so that it is called as stepdown transformer.
Measurement of no load loss and current open circuit test. In power plant this transformer is used as connecting transformer of generator to grid. The insulation condition of component parts of the transformer i. What is the difference between type test and routine test. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. The coil on input side is called the primary winding coil and that on the output side the secondary. The impulse also reproduces the stress peaks and switching surges in the net. These are most commonly used transformers and are available from milliwatts to megawatts range. The location of the station and the position of the equipment within the station. Here we discuss different types of transformers are the step up and step down transformer, distribution transformer, potential transformer, power transformer, 1. Insulation power factor testing of power transformers. Small dry type transformer shermco industries, inc. This transformer consists of a laminated core to reduce the eddy currents. Types of transformer different types of transformer.
The test is performed with a power factor test kit, and the connections are the same as for the megger test the insulation resistance test. The oil pressure test on transformer to check against leakages past joints and gaskets is included. Following is an approximate sequence for transformer testing. These are the most commonly used transformer types for all the applications. In a shelltype shell form transformer, the steel magnetic circuit core forms a shell surrounding the windings. Complete tests 1 and 2 for each winding of a threephase transformer individually with the remaining windings kept open. Each transformer asset manager must select the amount and type of. This test also performed as routine test of transformer. Type test and routine test of transformer electrical mastar. Type test of transformer confirms basic criteria of production lot. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
Jun 27, 2018 this webinar will introduce field technicians to the fundamental standards for transformer maintenance and testing. Various routine test of power transformerpart1 electrical. Square d brand ex low voltage distribution transformers. Inspect transformer and parts for shipping damage and moisture. Turns ratio the turns ratio test, also known as a ttr transformer turns ratio is, like most tests, easier to perform now than it used to be. Testing of power transformers seems like a similar experience. The type tests of the transformer confirm the main and basic design criteria of a production lot. The various types of transformer shown in the figure above are explained in the detail below. A burden test is typically performed at full rated secondary current value ex.
This is the most common type of transformer, widely used in electric power transmission and appliances to convert mains voltage to low voltage to power electronic devices. Guidelines to power transformer type, routine and special tests photo credit. Transformers regulate the voltage in circuits, but in some cases these can go bad and cause a circuit to not. Routine tests are performed during manufacturing on all transformers after the active part assembly completed and according to ts 267, iec 76 etc. So transformer ratio test is an essential type test of transformer. All efficiency values are at 35 percent of nameplaterated load, determined according to the doe test method for measuring the energy consumption of distribution transformers under appendix a to subpart k of 10 cfr part 431. There are 8 different tests commonly applied to power transformers. Transformer winding resistance measurement transformer ratio test transformer vector group test. They are available in power ratings ranging from mw to mw. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf. When mass production, there will some of the test items be implemented in order to make sure the quality the same with engineer samples. Transformer testing type test and routine test of transformer electrical4u. During ttr test voltage is applied to one transformer winding.
For dry type transformers, the insulation system consists of the cast resin winding and core insulation and the termination system insulation e. Because a test confirms what you know, if you can apply in real life what you have learned in a classroom, under strict, rigorous and controlled conditions. The size, type, and location of a transformer dictate the amount of external equipment. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2. Current transformer burdens are typically expressed in va. The burden test is performed to verify that the ct is capable of supplying a known current into a known burden while maintaining its stated accuracy. In addition to that some transformer tests are also carried out at the consumer site before commissioning. Guidelines to power transformer type, routine and special. Insulation resistance test and oil test of distribution transformer. The insulated laminations minimizes eddy current losses in the iron core. These types of transformers are used in electric power transmission and also in appliances to supply the low voltage. In addition to these, the transformer also goes through some other tests, performed on it, before actual.
Type tests are tests made on a transformer which is representative of other transformers to demonstrate that they comply with specified. The core, which makes a path for the magnetic flux. Pdf transformer testing type test and routine test of. That means routine tests of transformer include all the type tests except temperature rise and vacuum tests. Transformers are an electrical component that transmit electrical energy between at least two circuits. There are various test required on transformer to conform performance of transformer. The lightning impulse voltage test is executed as a type test to prove the constructive coordination of the transformer e. May 10, 20 so transformer ratio test is an essential type test of transformer. Customizable according to special customer demands. Type test certificate oftype test certificate of special test to prove suit ability to climatic class c2, to environmental class e2 and to fire behaviour test class f1 apparatusapparatus dry type power transformer designationdesignation trasformatore rated power kva. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the vital tests.
C electrical power from one voltage to another voltage keeping the. Mainly two types of transformer testing are done at manufacturer premises type test of transformer and routine test of transformer. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. Optional perform a powerfactor or dissipationfactor tipup test on windings rated greater than 2. This test can be repeated during the service life of the transformer and verified against the result obtained during manufacturing, as a check to determine if the insulation is malfunctioning or decaying. Type ex energy efficient low voltage dry type distribution transformer. The product has been tested according to relevant parts of the standards stated below. The transformer the principle parts of a transformer and their functions are. Dissolved gas analysis is the most commonly used method for determining winding insulation condition in oil type transformers, but is not possible for dry type transformers. The typical excitation current test data pattern for a threelegged core transformer is two similar current readings and one lower current reading.