Dec 12, 2017 vector group test, check the voltage phase shift of two or more transformer. To prepare the transformers for the tests to carry out the tests according to the standards and test procedures defined. Use features like bookmarks, note taking and highlighting while reading transformer inspection and testing electrical power plant maintenance book 1. While testing, basic testing requirements and testing codes are set out in the national and international standards. Due to the long lead time for repair of and replacement of transformers, a major goal of transformer protection is limiting the damage to a faulted transformer. Ltc because in order to change taps, the transformer has to be taken out of service or at least disconnected from the load. A primary part of commissioning a transformer involves testing it after its installation in the field.
Transformer and substation test system description trax is a multifunctional test set solution for transformer substation testing. A transformer bank composed of three singlephase units may be replaced by one 3phase transformer the magnetic core has three fluxcarrying legs two yokes, bottom and top, couple the flux of the three legs the sum of the three fluxes equals zero each leg contains the primary and secondary windings of one of the phases. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. Construction of a transformer the transformer mainly consists of the magnetic circuit, electric circuit, dielectric circuit, tanks, and accessories. The main elements of the transformer are the primary and secondary windings and the steel core. In this book we have laid down important aspects on transformer. Current transformer testing swp check this is the latest process zone version before use. 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. This intuitive, versatile, multilingual tool enables you to easily convert pdf file of any type into editable formats with the original layout and formatting retained. General inspection mechanical checks general visual inspection and compliance with the drawings and manuals. Transformer testing magnetic balancing test of transformer.
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. Transformer inspection and testing electrical power plant maintenance book 1 kindle edition by smith, wayne. Following is an approximate sequence for transformer testing. Among the three transformers operating in substation, one with rating of 315 mva failed in year of 20. Transformer testing free download as powerpoint presentation. It is carried out as a type test as well as routine test.
Testing is typically done with a megohmmeter, a tool similar to a multimeter but with a much higher capacity. As per iec specifications, test should be carried out by applying double the r. It is also known as iovtinduced over voltage test, it is one of the routine test of transformers usually performed to check in turn insulations of the windings. The 400220 substation has been commissioned near about 1998 with the transformation capacity of 1260 mva. The idea of a solidstate transformerhas been discussed since 1970. The core of a transformer is made of iron whereas thewinding which is wrapped over the iron core is made up ofcopper. Open as well as shorted terminals of nontested windings conclusions.
In an ideal transformer, a windings have no resistance b core has no. This intuitive, versatile, multilingual tool enables you to easily convert any type of pdf into editable formats with the original layout and formatting retained. The secondary coil, which receives energy from the primary winding and delivers it to the load. This amounts to a rigorous examination of the transformer intended to. The test system replaces numerous individual testing devices which makes testing with trax a time saving and cost effective alternative to conventional measurements using separate instruments. The performance parameters of interest can be obtained by solving that circuit for any load conditions. Introduction transformers are a critical and expensive component of the power system. Check nameplate ratings and hv, lv terminal markings. Vector group test of transformer testing of transformer. To prove that the transformer meets customers specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises. Check that all parts of the transformer are properly assembled and tight.
The vector group of transformer is an essential property for successful parallel operation of transformers. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. Testing facilities impulse generator discharge circuit recording system voltage divider for measurement standard impulse wave impulse withstand test 15. Some transformer tests are carried out for confirming the basic design expectation of that transformer. Basics, maintenance, and diagnostics xi contents continued page 9. 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. Rootcause analysis of transformer failure scenario at.
To fill in the test protocols, signing in the appropriate box. A powerful application, combining two utilities in one product pdf conversion and pdf creation. Feb 08, 2015 a routine test of transformer is mainly for confirming operational performance of individual unit in a production lot. Routine tests and type tests of transformers electrical4u. Transformer testing allows this aging process to be quantified and tracked, to help predict replacement intervals and avoid failures. Transformer inspection and testing electrical power plant. A transformer condition assessment from doble is a process, not a onetime event. Testing and commissioning instrumenttransformers free download as powerpoint presentation. Power transformer shortcircuit current withstand testing by.
All transformers are subjected to the following routine tests. Transformer condition assessment services from doble provide a solid foundation for effective maintenance programs based on industry best practices. Commonly known as the megger test, insulation resistance testing measures the quality of insulation within the transformer. The assessment generates recommended maintenance strategies and objectives which can be used to evaluate maintenance program effectiveness or. A presentation ontransformer testing using dpatt3bi 2. Transformer testing has developed considerably over the past years. Transformer testing commissioning, routine, diagnostic. Power transformer shortcircuit current withstand testing.
The core of the transformer is made up of silicon steel in order to provide a continuous magnetic path. A transformer transforms a frequency b voltage c current d voltage and current. May 10, 20 transformer manufacturers perform two main types of transformer testing type test of transformer and routine test of transformer. The easytouse software interface, powerdb, minimizes time required to learn how. Wave shape standard wave shape of impulse voltage is 1.
Transformer design to withstand switching must add strength 1. Power transformer testing power transformer factory test using ieee standards waldemar ziomek cg power systems canada ieee training, houston, texas, oct. Silsbee contents t page introduction 317 generalprinciples 318 nullmethod 321 deflectionmethod 325 experimentalresults. The initial purpose of solidstate transformers is to convert ac to ac for stepup or stepdown with a function the same as that of a conventional transformer. This tool enables you to convert any type of pdf into editable formats with the original layout and formatting retained. Testing is the most important activity when any equipment is designed. Vector group test, check the voltage phase shift of two or more transformer. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. You can also create pdf directly from microsoft office applications with just one clock, combine. The insulation of the transformer is the one to get a. Historical test data is valuable for determining damage to the transformer after a fault or failure has occurred elsewhere in the circuit.
Both paper and oil which are used for insulation in the transformer start getting degenerated and get decomposed. Meggers delta4000 automatically produces the itc for each transformer and provides confidence that the power factor tan. What is the correct procedure for dvdf and hv test on. Which of the following is not a basic element of a transformer. The phase sequence or the order in which the phases reach their.
Download it once and read it on your kindle device, pc, phones or tablets. This heats the transformer and the temperature of the transformer increases. Cts should be tested before they are mounted on the transformer. On distribution transformer this type of switch may also be used to change nameplate voltage andor configuration. Some variations in testing results in natural, depending on the moisture, cleanliness and the temperature of the insulation, but to pass, the insulation must. There are various test required on transformer to conform performance of transformer. We do transformer testing with new technology and equipment.
If we want to connect two transformer in parallel then their phase shift should be same, otherwise there will be a. Power transformer factory test using ieee standards. 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. 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. Testing of power transformers seems like a similar experience. The equivalent circuit parameters areavailabletothedesigner ofthetransformers. The primary coil, which receives energy from the ac source. The transformer the principle parts of a transformer and their functions are. Adobe acrobat reader is free software that lets you view and print portable document format pdf files. Our laboratory test results are accurate and reliable which satisfy customers and build up long and trustworthy business relation. 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. If the cts are already mounted in the transformer, large highcapacity current testing leads can be.
These tests are done mainly in a prototype unit not in all manufactured units in a lot. No one can precisely answer when equipment will fail, but its essential to manage the risk. Transformer testing preliminay test carried out on transformer before it is put into the tank. Losses of transformersthe transformers are made of 2 types of materials. The transformer has been built to standard damage has not been sustained during transit or installation. Background temperature rise testing techniques on current transformers can be divided in two major groups, according to their technology. The core, which makes a path for the magnetic flux. Customers can update the risk assessment either internally or with the help of doble for annual budget preparation. In some cases, cts may have to be tested by connecting test leads to both ends of an installed bushing. Before proceding with transformer measurements the test engineer will become familiar with the safety rules of section 2.
658 1303 906 1243 852 682 526 1279 407 1516 353 192 1115 770 496 194 24 410 541 339 1178 1571 1195 543 73 1394 1573 291 8 217 845 309 1316 1486 900 939 21