All materials and relevant documentation to this testing works shall be checked by the responsible personnel prior to the commencement of testing activities. The primary current of minimum of 25% rated primary current to be injected on primary side of ct with secondaries shorted and the secondary current can be measured and recorded for all cores limits. Home download center electrical engineering books and technical. 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. Making a wellinformed choice in equipment for transformer testing is an important step towards ultimately improving transformer life management decisions. Power transformer testing procedures and schemes photo credit. If no evidence of distress or insulation failure is observed by the end of the total time of voltage application during the. Also information about some types of transformers are gathered as well as distribution transformer connections installations. Our distribution transformer test system dtts has been designed with these requirements in mind, as a multifunctional tool for testing distribution transformers. Himalayal provides innovative products that comprise high voltage test equipment, fullset high voltage test instruments, onsite test systems and online monitoring systems, and services regarding tests, diagnostics and asset monitoring for clients in power industry. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. Highvoltage transformers are some of the most important and expensive pieces of equipment.
On distribution transformer this type of switch may also be used to change nameplate voltage andor configuration. Testing of power transformers seems like a similar experience. Instrument transformer theory and testing steve hudson, pe engineering manager 10737 lexington drive knoxville, tn 37932 phone. The test setup and procedure of the frsl test is the same as for shortcircuit. General inspection mechanical checks general visual inspection and compliance with the drawings and manuals. A transformer is a device used to change the voltage levels of electricity to facilitate the. Turns ratio tests optional test this test is to ensure the turns ratio of ct at all taps. Check that all parts of the transformer are properly assembled and tight. Use small jumper to short the ct secondary from ct box, the measurement will be gone at panel.
Inspection, testing and commissioning of electrical. The ac hipot test values for voltages up to 69 kv are presented in table 1. Measurement of winding resistance measurement of voltage ratio and check of. Also there is detailed analysis about the consisting of a distribution transformer. The equivalent circuit parameters areavailabletothedesigner ofthetransformers. The paper presents the method of selection, calculation and measurements of generator that is built into the new transformer test station.
As some transformer tests are better suited as commissioning and diagnostic tests, the reason for testing e. Best transformertestproceduresen linkedin slideshare. Potential voltage transformers testing and precommissioning check potential voltage transformers can be broadly divided in to two type. May 10, 20 so transformer ratio test is an essential type test of transformer. Synchronous generator for induced ac voltage test of. There are several facets to a transformers overall health dielectric, magnetic, mechanical and thermal and many components that must be tested to verify the transformers whole condition. Purpose and scope the purpose of this standard work practice swp is to provide guidelines for testing methods for capacitive and inductive voltage transformers. The procedure employed here is the manual technique where computerized machine for such tests are not available. Check nameplate ratings and hv, lv terminal markings. The insulation of the transformer is the one to get a. Transformer testing techniques and standard development netaworld transformer testing techniques and standard development 61 feature transformer manufacturers and field operators have always benefitted when new technologies are applied during design, manufacturing, commissioning, and operational processes that. Ensure the ct is connected to system properly in all respect primary and secondary.
Higher voltage and lower current reduce the required size and cost of transmission lines. The manual provides procedures for checking of external circuitry and energizing the ied, parameter setting and configuration as well as verifying settings by secondary injection. Synchronous generator for induced ac voltage test of single. Potential transformer testing ptvt valence electrical.
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. There are various test required on transformer to conform performance of transformer. The transformer has been built to standard damage has not been sustained during transit or installation. Voltage transformer testing competency assessment sp0508c06. Type of transformer testing type test routine tests special tests pre commissioning test winding resistance measurement ratio test magnetic balance. Common precommissioning tests of transformer insulation resistance values of various winding should be checked. The followings tests shall be carried out to ascertain the status of a faulty transformer especially the distribution transformer inservice in the. Along with different precommissioning tests, different instruments associated to the transformer also to be checked. Transformer tests best balikesir elektromekanik sanayi tesisleri.
Electrical test equipment application solutions from megger. Transformer testing has developed considerably over the past years. Transformer pd and induced voltage withstand test system. The primary and secondary voltages are measured to determine the ratio v2v1. Stationary and mobile transformer transformer testing. Open as well as shorted terminals of nontested windings conclusions. Tm 5686 power transformer maintenance and acceptance.
Uettdrts24a design testing and commissioning procedures. All transformers are subjected to the following routine tests. The windings are shorted and the test voltage is applied to one winding while the. Voltage ratio test, magnetic balance test, winding resistance test, insulation. Testing procedures for hv voltage transformers testing procedures for hv voltage transformers photo credit.
Voltage transformer testing job safety analysis sp0508c03. Pre commissioning test of transformer pdf tests for transformer and cable oil. The manual describes the process of testing an ied in a substation which is not in service. Potential transformer testing ptvt i cowrote an article for the neta world magazine in 20042005 that covers several different manual techniques for potential transformer testing that explains several lowtech solutions for potential transformer testing. The windings are shorted and the test voltage is applied to one winding while the current through. Tm 5686 power transformer maintenance and acceptance testing. These tests are done mainly in a prototype unit not in all manufactured units in a lot. Voltage transformer testing swp page 1 of 19 standard work practice sp0508 ver 7 ergon energy corporation limited abn 50 087 646 062 1. Some transformer tests are carried out for confirming the basic design expectation of that transformer. Transformer, operation, testing and maintenance 33kv and below 9. Equipment required following equipment is necessary to perform testings. A routine series of diagnostics and testing for your current transformer should include ct saturation testing to identify the knee point against ieee or iec standards, ct ratio tests to identify that the voltage ratio is within expected parameters and current transformer resistance testing for both the transformer windings and ct insulation. Ptb testing instructions, volume 12, instrument transformers, 1977, with amendments 579 individual testing one by one successive testing charge.
In this book we have laid down important aspects on transformer. Impulse test concepts by philip j hopkinson, pe conclusions. Basics, maintenance, and diagnostics xi contents continued page 9. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to the power system. A variable ac source is applied on the primary side. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. Contract specific procedure for testing of electrical equipment and 2kv ohl.
This test allows the engineer and relay technicians to validate all the cts and pts secondaries, transformer winding con. The fault free operation of a power transformer is a factor of major economic. Current transformers play an important role in the monitoring and protection of electrical power systems. A procedure for investigating the internal pd source is described in. This test also performed as a routine test of transformer. These can be of electromagnetic of capacitive voltage transformer type cvt. Over the years, a number of methods have been introduced and employed on. Power transformer testing procedures and schemes eep. The performance parameters of interest can be obtained by solving that circuit for any load conditions.
Some tests and procedures may be performed by specialists during the assembly phase. Oct 11, 2015 shortcircuit may be a preset or b post set duration of each test being 0. Routine tests are carried out on every unit manufactured. The classifications on the insulation design shall independently of the test procedure be. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. To prove that the transformer meets customers specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises.
Heres a summary of the current transformer testing paper. Zeras testing systems can be designed for testing instrument transformer manuell or automatic. Back to the basics current transformer testing ct as test equipment becomes more sophisticated with better features and accuracy, we risk turning our field personnel into test set operators instead of skilled field service technicians. The transformer is one of the most reliable pieces of. Current transformer testing swp check this is the latest process zone version before use.
Routine tests and type tests of transformers electrical4u. The current transformer is solely assessed through its external behavior without considering what is happening inside. Transformer design drytype and cast resin, protection methods are being referred and more also included in the specific research document. Effective testing, precommissioning and commissioning of electrical. After, installation of power transformer, several precommissioning tests to be done before putting the transformer in service. Know the condition of your transformer to get the most out of your asset. The circuit connection shall be made as shown figure 4. High voltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. The fault free operation of a power transformer is a factor of major.
Field testing of a power transformer before putting into service 50mva. The transformer must be deenergized before this procedure, unless it. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to. Performance test of faulty distribution transformers along. Testing and diagnostics of power transformers brochure. Sweep frequency response analysis sfra has become a powerful tool in advanced power transformer assessments and probably one of the main and first tools used to diagnose troubled transformers or as a regular maintenance test.
The test and assessment of transformers is a complicated task. Theoretical turn ratio hv winding voltage lv winding voltage. Ltc because in order to change taps, the transformer has to be taken out of service or at least disconnected from the load. Voltage transformers testing and commissioning guidelines. Voltage ratio test, magnetic balance test, winding resistance test. Nov 17, 2019 after, installation of power transformer, several precommissioning tests to be done before putting the transformer in service. Transformer, operation, testing and maintenance 33kv and below. In this test we confirm the ct secondary connection. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. While online diagnostic systems and computerized testing methods are very helpful. Shortcircuit may be a preset or b post set duration of each test being 0. Testing of three phase power transformer ijireeice. Voltage transformer testing swp page 2 of 19 standard work practice sp0508 ver 7 ergon energy corporation limited abn 50 087 646 062 sp0508r01. Dc dielectric withstand test voltage shall not exceed 100 percent of the ac rms test voltage specified in ansi c57.
Testing power transformers highvoltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. Feb 08, 2015 a routine test of transformer is mainly for confirming operational performance of individual unit in a production lot. Purpose this manual contains a generalized overview of the fundamentals of transformer theory and operation. The three phase cylindrical synchronous generator 800 kva, 200 hz with special damper bars is most suitable to be used as a power supply for testing of singlephase and threephase power transformers. Ac dielectric test for acceptance and routine maintenance for liquidfilled power transformers transformer winding voltage kv factory test ac voltage kv acceptance field test ac. Uettdrts24a design testing and commissioning procedures for. 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. Nov 26, 2010 traditional current transformer testing follows a blackbox approach. Both paper and oil which are used for insulation in the transformer start getting degenerated and get decomposed.
This heats the transformer and the temperature of the transformer increases. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. Megger guide to electrical insulation testing pdf instrumart. Testing power transformers high voltage transformers are some of the most important and expensive pieces of equipment required for operating a power.
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