During that time, the effects of aging, regular operation, network faults. Testing and commissioning instrumenttransformers free download as powerpoint presentation. Making a wellinformed choice in equipment for transformer testing is an important step towards ultimately improving transformer life management decisions. As the pt secondary is normally grounded through an internal jumper, an external switch is often used to isolate the pt from ground during testing. Testing potential transformers valence electrical training services. Secondary winding secondary winding apply 500v for 1 minute. If no evidence of distress or insulation failure is observed by the end of the total time of voltage application during the. Knee point voltage and magnetization curve have to be tested by using current transformer test kit mct. After commissioning, secondary current measurement shall be carried out in ct circuits.
The dc voltage test momentarily imposes a small dc voltage on one side of a ct primary and the direction of the momentary deflection of a meter on the opposite side secondary. Testing and commissioning requirements for switchgear. Testing and commissioning of hv power transformers. Being an intrical part of the transformer manufacturing, we have a vast experience in installing and commissioning different types and sizes of transformer across the globe with our mobile service equipment, including highvoltage test equipment, we can commission the unit in the shortest possible time, thus shortening your downtime. Substation testing and commissioning sunday, july 15, 2012. Inspection, testing and commissioning of electrical. Voltage transformer testing job safety analysis sp0508c03. Everyday we are witnessing new innovation that make us more advanced.
These tests are done to assess the condition of transformer after installation and compare the test results of. Testing potential transformers relay testing training for. Along with different precommissioning tests, different instruments associated to the transformer also to be checked. Testing current transformers burden test only if we cannot get to the primary side of the ct we can check that the output is constant as burden changes. Phase angle check shall be done for correct direction. Apply the formula or plot the values in the graph to get the vector group. It rating plate show nominal voltage, current of primary and secondary voltage at various of the tap changer, connection symbols vector group, % impedance weight of oil etc. May 10, 20 the transformer testing performed before commissioning the transformer at the site is called the pre commissioning test of transformer. Perform electrical performance tests on potential transformer circuits. Switchcircuit breaker testing 25 2 transformer testing 26 214 rotating machine testing 27 215 protective relays 28 217 ground system testing 29 218 chapter 3 component testing introduction to component testing 31 31 circuit switchers 32 31 transformers 33 32 switchgear medium voltage 34 33. The ac hv test value should not surpass 75% of the factory test value. This practical commissioning test was developed decades ago and the authors are simply presenting the theory and procedure of how the test performs in the substation. Potential voltage transformers testing and precommissioning check potential voltage transformers can be broadly divided in to two type.
Terminal marking of power transformers is determined by ansi standards. These devices use standard transformer theory with 23 windings one primary with one or two secondary windings. When ac hipot tests are used for routine maintenance, the power transformer can be examined at rated voltage for 3 min instead of testing at 65% of factory test voltage. Medium voltage transformer testing 7200db1001 data bulletin 112010 electrical equipment should be installed, operated, serviced, and maintained only by qualified personnel. Testing and commissioning of hv power transformers, circuit. Primary winding secondary winding apply 500v for 1 minute. Sep 28, 2018 current transformer ct testing procedure in sulation resistance measurement.
Capacitive voltage transformers cvts have been widely used. The capacitors are connected between the system voltage and the polarity of a pt. Highvoltage transformers are some of the most important and expensive pieces of. For primary side, apply voltage depending on rating of voltage rating of vt. A primary part of commissioning a transformer involves testing it after its installation in the field. May 29, 2015 voltage transformers are used around the clock throughout the energy grid, and their life span can reach up to 40 years.
A variable ac source is applied on the primary side. Voltage transformers testing and commissioning guidelines. Technical specification for startup and commissioning of. Select the megger range corresponding to the ratings of the equipment under test. Mechanical changes to windings, caused for example by transportation, and contact problems at other connections can be detected before first operation. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals. Transformer, throughfault, substation, commission and testing. Insulation resistance tester, microohmmeter, high voltage test set, digital voltmeter. Nonobservance can result in death, personal injury or substantial. This method is time consuming, but only requires a voltage source, a resistance, and a voltmeter.
After, installation of power transformer, several precommissioning tests to be done before putting the transformer in service. Substation primary plant and secondary systems field testing swp. Cvts are often used in high voltage 115kv and higher applications and use a series of capacitors as a voltage divider. Netaecs electrical commissioning specification first written in 2015 to help shift the use of. Transportation, erection, testing and commissioning ieema. The pre commissioning test result should to compare with manufacture test result basically on transformer name plate or manual guideline and international standard ieee standard or interplant standardsteel industry, code of practice for testing and commissioning of power transformer and related switchgears, ipss. Neta is not only for commissioning new equipment but for testing the reliability and performance of existing equipment. No responsibility is assumed by schneider electric for any consequences arising out of the use of this material. Low voltage dry type transformer construction checklist page 1 of 4 version 0206 low voltage dry type transformer construction checklist under 500 kva project. The ratio and phase angle of an instrument transformer may be accmately determined by laboratory. Along with different pre commissioning tests, different instruments associated to the transformer also to be checked.
Current transformer ct testing procedure in sulation resistance measurement. Being an intrical part of the transformer manufacturing, we have a vast experience in installing and commissioning different types and sizes of transformer across the globe with our mobile service equipment, including high voltage test equipment, we can commission the unit in the shortest possible time, thus shortening your downtime. Figure 2 showed the flow chart when doing the testing on pre commissioning of power transformer. Multifunctional primary test system for substation. Jan 26, 2017 schneider electrics transformer erection and commissioning. Ensure variation in secondary volts as the taps are changed and compare the results with manufacturers test report or ratio mentioned on transformer nameplate.
Instrument transformer theory and testing steve hudson, pe. Transformer installation amman west substation project 17 02 2016. Maintenance testing is more relaxed in values and testing requirements then theacceptance testing specification when an electrical commissioner is tasked with helping set up a maintenance program, neta mts should be the first book opened. Feb 07, 2018 current transformers, together with voltage transformers vts or potential transformers pts, which are designed for measurement, are known as an instrument transformer. Highvoltage transformers are some of the most important and expensive. Introduction substation commissioning and testing is a critical task prior to substation energization to ensure all equipment will function safely in the intended manner. Instrument transformer testing instrument transformers for metering purposes must have a high degree of accuracy up to class 0. As you already know, substations are the points for controlling the supply of power on different routes by means of various equipment such as power transformers, circuit breakers, ctsvts, compensating equipment, isolators, etc. Transformer testing commissioning, routine, diagnostic. The primary and secondary voltages are measured to determine the ratio v2v1. Transformer vector group the vector group test is importent test in the transformer testing.
Power transformer testing and commissioning guidelinesoil. H 1, h 2, x 1, x 2, where h is the higher voltage rated winding and x is the lower voltage winding. Perform electrical performance test on control power transformer circuits. Replaces 7200pd9206, 031992 medium voltage transformer. Routine tests and type tests of transformers electrical4u. Replaces 7200pd9206, 031992 medium voltage transformer testing. Commissioning procedure of power transformer in transformer testing it can be classified into power and distribution transformers.
Common electrical tests on power transformers omicron. Installation and commissioning transformer service abb. Measuring the voltage drop at the source combined with ohms law will give us the burden impedance. Pre commissioning of power transformer engineering essay. Before do the testing, the testers must be following the guideline to avoid the most accident because testing work on transformer need to be done carefully and cautiously. Testing power transformers high voltage transformers are some of the most important and expensive pieces of equipment required. Cvt diagnostic testing reference cvt test equipment specific document sp0506. The above equipment and systems integral to them are complete and ready for functional testing. Testing potential transformers relay testing training. To learn more, visit our commissioning routine diagnostic tests page. 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.
Voltage transformer testing competency assessment sp0508c06. Basics, maintenance, and diagnostics xi contents continued page 9. Twowinding transformers have terminals designated by h and x e. Current transformer burdens are typically expressed in va. Common electrical tests on power transformers before the initial use of a transformer acceptance tests are required for confirming that it is working properly to guarantee safe operation. The story of transformer stability the transformer stability test used to conform the ct connections for differential and ref protection. Schneider electrics transformer erection and commissioning. Contract specific procedure for testing of electrical equipment and 2kv ohl. To transform currents or voltages from a usually high value to a value easy to handle for relays and instruments. The test and assessment of transformers is a complicated task. Switchgear testing and commissioning procedure electrical.
Use megger mit1020 to measure insulation resistance. Test value a bolt torque levels are checked in accordance with u. Analyzing the voltage drop patterns throughout the circuit confirms the wiring is correct. Sp0504 power transformer testing swp pdf file, 110. Throughfault test apply the balance three phase voltage, equal voltage magnitude and displaced 120 degree among phases, on one side of the transformer or. Cvts are primarily used for voltage measurement, providing voltage signals to metering units, protection relay devices, and automatic control. Technical specification for startup and commissioning of new. Dc dielectric withstand test voltage shall not exceed 100 percent of the ac rms test voltage specified in ansi c57. Voltage transformers are used around the clock throughout the energy grid, and their life span can reach up to 40 years. Testing of high voltage cables manual horizon power. Testing and commissioning of hv power transformers, circuit breakers, cts and vts this technical article provides guidance to substation personnel in carrying out testing and commissioning of high voltage power transformers, circuit breakers, current and voltage instrument transformers. Substation testing and commissioning thursday, april 26, 2012. The test equipment should be able to provide a threephase supply of currents and threephase voltage. Apply 3 phase supply voltage 415 v ac across the primary termination of the transformer.
Power transformer testing competency assessment sp0504c. Measure the voltage at the both primary and secondary termination at all the phases. After, installation of power transformer, several pre commissioning tests to be done before putting the transformer in service. Never apply voltage when transformer is under vacuum. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. This amounts to a rigorous examination of the transformer intended to. Tm 5694 commissioning of electrical systems for command. Power transformer testing and commissioning guidelines r. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of transformer. Voltage transformer testing page 8 9 current transformer testing page 6 7 power and distribution transformer diagnosis page 10 11 switchgear circuit breaker testing page 20 21 sampled values testing page 24 25 grounding system analysis page 14 15 commissioning protection systems page 22 23 cpc 100 applications. Scribd is the worlds largest social reading and publishing site.
These can be of electromagnetic of capacitive voltage transformer type cvt. Ensure the ct is connected to system properly in all respect primary and secondary. Safety information dangerous voltages can occur on the connectors, even though the auxiliary voltage has been disconnected. Medium and large power transformers in distribution or transmission power system are often. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to. Current transformers, together with voltage transformers vts or potential transformers pts, which are designed for measurement, are known as an instrument transformer. Medium voltage transformer testing 7200db1001 data bulletin 112010 electrical equipment should be installed, operated, serviced, and maintained only by.
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