Mv transformer testing pdf

Medium voltagelow voltage mv lv transformer substations 1. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 1. Such a failure could result from a new operator in the winding department the hipot test a versatile test. Power factor is defined as the cosine of the phase angle between voltage and current. It is carried out as a type test as well as routine test.

In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. To prove that the transformer meets customers specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises. In 2003, abb compiled all its knowledge in a book titled testing of power transformers. Pdf transformer is a static device which transforms a. Transformer ct testing 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. This is useful for powering advanced machines and for mediumrange energy transport. Power transformer testing swp check this is the latest process zone version before use. These tests are done mainly in a prototype unit not in all manufactured units in a lot.

The swer isolating transformer is a medium voltage phase to phase connected winding and a 19kv secondary winding for swer application. Back to the basics current testing valence electrical. 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. No responsibility is assumed by schneider electric for any consequences arising out of the use of this material.

In this book we have laid down important aspects on transformer. When a decision to supply power at mv has been made, there are two widelyfol lowed methods of proceeding. Testing of power transformers seems like a similar experience. The following sections of the ansineta standard for acceptance testing specifications for. Transformer installation method statement electrical. Medium voltage products technical guide the mvlv transformer. Prior to start of terminations this is to ensure that the transformer are in a defect free state. The book represented the collective wisdom of over 100 years of testing power transformers. Oct 25, 2018 insulation resistance tests megger test are carried out on all windings, core and core clamping bolts. 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. Mar 29, 2019 confirm the proper input to the transformer.

This paper will focus only on motor testing yellow highlight. The power factor of this transformer was found to be 7%, greater than the upper limit of 5%. Back to the basics current testing relay testing training. Replaces 7200pd9206, 031992 medium voltage transformer testing. The mvtransformer is used to turn high voltage packets 512 eup into medium voltage packets 128 eup and back. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. The quality of a transformer is of utmost importance for safety, industrial and financial reasons. Twowinding transformers have terminals designated by h and x e. Ensure the ct is connected to system properly in all respect primary and secondary. We just apply three phase 415 v supply to hv winding, with keeping lv winding open. Basics, maintenance, and diagnostics xi contents continued page 9. Maintenance of transformers a detailed checklist electrical4u. For ideal insulation, the phase angle is 90 degrees, but in practice, no insulation is ideal. May 10, 20 the transformer testing performed before commissioning the transformer at the site is called the precommissioning test of transformer.

A transformer changes the voltage level or current level on its input winding to another value on its output winding using a magnetic field. Insulation tests on current transformers rated 600v or less are usually performed at vdc. A power transformer requires various routine maintenance tasks including measurement and testing of different parameters of the transformer. The power factor test determines the power loss of the transformers insulation system by measuring the power angle between an applied ac voltage and the resultant current. Some of the process failures that can be detected by a productionline hipot test include, a transformer wound in such a way that creepage and clearance have been reduced. This ms excel spreadsheet is actually detailed instruction for each procedure necessary for correct testing of power transformer.

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. Get access to premium hv mv lv technical articles, electrical engineering guides. General visual inspection and compliance with the drawings and manuals. Types of pd testing offline testing equipment disconnected from power system factory testing for quality and insitu for condition assessment online testing equipment is connected to the power system and usually in normal operation used for condition assessment test methods, passfail. Types of electric motor testing unlike vfds, electric motors have several widely. Watch our video about medium and highvoltage eis transformer testing to arrange testing of transformers, request a quote online now or call 6369495835. Natural ester dielectric fluid overview envirotemp fr3. The percent x and percent r values are desirable for calculation. The mv transformer is used to turn high voltage packets 512 eup into medium voltage packets 128 eup and back.

The polarization index pi and dialectric absorption ratio dar were both less than 1. Knee point voltage and magnetization curve have to be tested by using current transformer test kit mct. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062. Routine tests and type tests of transformers electrical4u. Ac hv test value should not surpass 75% of the factory test value. Medium voltage transformer testing 7200db1001 data bulletin 112010 electrical equipment should be installed, operated, serviced, and maintained only by. Standard for acceptance testing specifications for. The decision of a mv or lv supply will depend on local circumstances and considerations such as those me n tioned above, and will generally be imposed by the utility for the district concerned. Testing iec 600765 threephase transformer tested with 9 shortcircuit applications of 0. Special test transformer nameplate data year of manufacture 2006 rated power hvmv for onan, kva 468468 rated voltage hvmvlv, kv 224. We perform one group on a routine basis known as preventative maintenance, and the second group on an adhoc basis i. Check that all parts of the transformer are properly assembled and tight.

Technical guide the mvlv transformer substations abb group. Method 1 substation with a single transformer when the plant foresees installation of an. Use the dmm in ac mode to measure the transformer primary. By default, the transformer accepts 512 eut input on the three dotted side of the block and outputs 128 eup on each of the single dotted sides. Types of pd testing offline testing equipment disconnected from power system factory testing for quality and insitu for condition assessment online testing equipment is connected to the power system and usually in normal operation used for condition assessment test methods, passfail criteria, standards are. Terminal marking of power transformers is determined by ansi standards. A mv lv transformer electrical substation consists, therefore, of the set of devices dedicated to the transformation of the voltage supplied by the distribution network at medium voltage e. Testing and commissioning of mvhv cables example of asbestos paper insulation wrap on highvoltage cable inside an underground cable vault. What is the megger test procedure for transformers. Mv and hv powerfactor correction banks powers up to 100mvar voltages up to 220kv frequency of 50 or 60hz tuned capacitor banks tuned on harmonics from the 2nd to the th power up to 100mvar voltage up to 150kv frequency of 50 or 60hz mv and hv special filters such as high pass, second order filters with double tuning.

Standard for acceptance testing specifications for electrical. Therefore, it is recommended to demagnetize the core after performing this test. The function of a transformer primaryside protective device is, in general, to provide system protection as. Some transformer tests are carried out for confirming the basic design expectation of that transformer. H 1, h 2, x 1, x 2, where h is the higher voltagerated winding and x is the lower voltage winding. The transformer must be deenergized before this procedure, unless it.

There are various test required on transformer to conform performance of transformer. Section 7 of the ansineta standard for acceptance testing specifications for electrical power equipment and systems may be reproduced and used on a cut and paste basis for the particular type of equipment to be tested. These tests are done to assess the condition of transformer after installation and compare the test results of all the low voltage tests with the factory test reports. The insulation must be just the opposite from a conductor. Figure 1 shows a typical mv motor and vfddriven system. Testing manual for electrical equipment nahed alhajeri 1and anantha madhavan 2 abstract quality assurance qa refers to a program for the systematic monitoring and evaluation of the various aspects of a project, service, or facility to ensure that standards of quality are being met. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. Replaces 7200pd9206, 031992 medium voltage transformer. In order to test this system, an end user can make a selection from up to four types of testing varying in breadth and scope as shown below. Check nameplate ratings and hv, lv terminal markings.

Sep 01, 2017 switchgear system to be factory tested for all the accessories like circuit breaker, current transformer, voltage transformer, ammeter, volt meter etc. C electrical power from one voltage to another voltage keeping the frequency same by. The standard megger testing equipment is used, the line terminal of which is connected to the winding or core bolt under test. Medium and high voltage eis transformer testing with ieee. Pdf design and operational testing of a 510mva hts.

Testing and commissioning requirements for switchgear. Design and operational testing of a 510mva hts utility power transformer article pdf available in ieee transactions on applied superconductivity 152. 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. There are two main types of maintenance of transformer. If the measurement is less than 80 percent of the expected voltage, the fault could lie in either the transformer or the circuitry providing the primary with power. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. All works prior to testing location to be barricaded and for precautionary safety measure. A transformer consists of two electrically isolated coils and operates on faradays principal of mutual induction, in which an emf is induced in the transformers secondary coil by the magnetic. Therefore, for actual values, obtain nameplate impedance from owner or manufacturer. Transformer testing has developed considerably over the past years. Power transformers transform electrical energy from one voltage level to another by stepping voitages up for transmission to minimize losses, or. All materials and relevant documentation to this testing works shall be checked by the responsible personnel prior to the commencement of testing activities.

Transformer testing type tests and routine tests of. Remove the neutral ground and isolate the ct from any associated burden. Several layers of the soft and friable insulation are wrapped around the cable in long, wide strips. In comparison to the impulse procedure, sfra is preferred for frequency domain.