Condition monitoring of power transformer by using sfra test. Pdf this paper presents how earth fault damage in the transformer can be detected by sweep frequency response analysis sfra. The test methods used by the authors for presenting the results are described. Sweep frequency response analysis sfra sea trasformatori. To connect the ground reference cable and test leads and run sfra. Once the transformer has passed the fat, it is ready for shipment to a new site, where a testing crew will commission the unit before energization. This test is very reliable for condition monitoring of physical condition of transformer windings. Measurement considerations using sfra for condition. Iec 6007618, power transformer, reproducibility, sfra, sweep frequency response. The testing method is fairly simple since the development of specific fra test equipment. Impulse tests used to produce a frequency response may. This test also performed as a routine test of transformer.
Power transformer faults identification using sfra t. So for ensuring proper performance of electrical power transformer, voltage and turn ratio test of transformer one of the important tests. Power transformer factory test using ieee standards. Sfra, detect of winding deformation in power transformer. It evolved from the simple gonogo verdict into a sophisticated segment within transformer manufacturing. The detc position should not be moved for an sfra test until all options are exhausted.
Transformer service trafositetesting verify the reliability. Sfra 5000 is a standalone sweep frequency response analyzer for the high accuracy transformer analysis and integrates the sts and td 5000 family test sets. Analysis of the results, which are in the form of frequency response traces can, however, be daunting to new users. Use the doble m5400 sweep frequency response analysis test set to investigate mechanical integrity of transformers, reactors and other equipment consisting of windings. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of the transformer. Provided the test is done correctly this provides a clear definition for acceptability. This paper presents how interpretation of sweep frequency response analysis sfra traces can be done for the open circuit and short circuit winding faults on the 10 kv a power transformer. The iec 6007618 standard describes the recommended procedure for a proper. Diagnostic testing and monitoring of power transformers. The diagnostic t process uses some of the current diagnosis methods e. Transformer testing has developed considerably over the past years. Major utilities and service companies have used the fra method for more than a decade. Sweep frequency response analysis sfra is one of the most powerful diagnostic tools for assessing mechanical damage to a transformer winding.
Frequency response analysis of power transformers 100215. It measures the frequency response of passive element rlc of the apparatus. Richenbacher presented at the 43rd doble intl client conference. Sweep frequency response analysis sfra is a method to evaluate the mechanical integrity of core, windings and clamping structures within power transformers by measuring their electrical transfer functions over a wide frequency range. It is a noninvasive, lowvoltage diagnostic test, delivering comprehensive information. Ac voltage is preferable to dc voltage for transformer testing because ac voltage simulates the internal stress that. According to 3 sfra method determines the transformer responses in a time or frequency area. The value that sfra provides to its users is quite easily established, by research of. Starting with a transformers factory acceptance testing fat and continuing through its service life, mechanical, dielectric, thermal, and electromagnetic parameters are evaluated. Get access to premium hvmvlv technical articles, electrical engineering guides. The sfra traces of this testing would be utilized as base line or previous data. Basics, maintenance, and diagnostics xi contents continued page 9.
Pdf power transformer faults identification using sfra. Before doing practical simulation of transformer damages, first sfra testing has been carried out on healthy condition of the transformer. Sweep frequency response analysis sfra for the assessment of winding displacements and deformation in power transformers. The response is measured on the other end of the winding u2f. Sfra is an offline testing and it can be carried out for any voltage rating of. Frequently asked sweep frequency response analysis. So transformer ratio test is an essential type test of transformer.
Sweep frequency response analysis sfra test on transformer see real results hello, this video is for deep understand about sweep frequency response analysis. Electrical interferences in sfra measurements how to. Fra, rms, lcr, scope compliant to iec6007618 standard light and easy to carry. Interpretation of sweep frequency response analysis sfra. It is assumed that you are familiar with professional standards and safety practices. Main core deformation, open circuits, shorted turns, residual magnetism. Interpreting sweep frequency response analysis measurements.
The power transformer of rating 10 kva, 1 v440 v, 3phase, 50 hz, dyn11 has been specially developed inhouse for carrying out sfra testing by. Power transformer faults identification using sfra. Pdf power transformer is one of the most imperative equipments in a high voltage electric power system. Nov 17, 2019 sweep frequency response analysis test or in short sfra test can detect efficiently, displacement of transformer core, deformation and displacement of winding, faulty core grounds, collapse of partial winding, broken or loosen clamp connections, short circuited turns, open winding conditions etc. This guide is based on the operation of the n4l sfra45 sweep frequency response analyzer and will provide a. Transfer function measurements have been used as a diagnostic tool to detect mechanical failures in power transformers. Electrical faults are often easy to detect using sfra, but are. Transformers are the most critical part of electrical transmission and distribution network, also when it is come to quality and continuity requirements on delivery of electrical energy. The two outside windings a and c phases have the same general shape. Sweep frequency response analysis sfra proceeds by applying a sinusoidal signal of constant amplitude and variable frequency to one end of the winding under test u1f. The measurement of sfra can be a part of regular transformer maintenance. Pdf sweep frequency response analysis sfra for the. Sweep frequency response analysis sfra for the assessment.
For safe testing, the test setup must meet the following requirements. Page 22 of 63 june 2003 fist 331 transformer diagnostics x3x2. Sweep frequency response analysis test sfra test electrical4u. Since most of evaluation procedures is based on comparison. Sweep frequency response analysis this test relies on inductancecapacitance combinations to produce resonances to a lowvoltage ac signal. In this book we have laid down important aspects on transformer. Since then several specialized products have been introduced. Frequency response analysis often referred to as fra or sfra is a powerful and sensitive method for testing the mechanical integrity of transformer cores, windings, and press frames, in power transformers. Power transformer testing swp check this is the latest process zone version before use. Frequency response analysis on power transformers omicron. Doble sfra accessories include two options for measurement cables, as well as a performance verification cell to help you confirm that your m5400 sweep frequency response analyzer and leads are working properly. Use of frequency response analysis to detect transformer winding movement a report submitted to the school of engineering and information technology, murdoch university in partial fulfilment of the requirement for the degree of bachelor of engineering ibrahim mohammed ahmed thesis final report 20 supervisor. However, for inservice assessment it is considered by some that this method is.
The resulting overloads of grid sections can lead to farreaching supply and production failures. These accessories give you the opportunity to choose what best fits your testing program and ensure testing accuracy. Page 1 of 14 standard work practice sp0504 ver 4 ergon energy corporation limited abn 50 087 646 062. Before the 1990s no designated sfra equipment for transformer analysis existed. Ac voltage is preferable to dc voltage for transformer testing because ac voltage simulates the internal stress that the transformers face during operating conditions. Sweep frequency response analysis test or in short sfra test can detect efficiently, displacement of transformer core, deformation and displacement of winding, faulty core grounds, collapse of partial winding, broken or loosen clamp connections, short circuited turns, open winding conditions etc. Testing of power transformers seems like a similar experience. A sfra open circuit test will show the response of core and windings, while a sfra short circuit test only shows the response of windings. The transformer under test must be completely deenergized and isolated from the system. As such, their condition is critical for reliable, faultfree operation. Iec6007618 sfra of power transformers, typical test sequences. By using the latest proven sfra test techniques, it is possible to accurately assess transformer condition without dismantling it.
Sfra testing on transformers dismantling a power transformer to determine its condition is hardly ever a practical possibility. Circuit modeling thus needs to accurately represent the behavior of a. Transformer sweep frequency response analysis sfra by g m kennedy, a j mcgrail and j a lapworth, doble engineering, sweep frequency response analysis sfra is one of the most powerful diagnostic tools for assessing mechanical damage to a transformer winding. In a power transformer it measures the fault current of the winding over a wide range of frequencies. Sweep frequency response analysis free download as powerpoint presentation. Transformer testing commissioning, routine, diagnostic. The technique of sfra is a major advance in transformer condition monitoring analysis.
No other single test method for the condition assessment of power transformers can deliver such a diversity of information. This thesis presents fra which includes sweep frequency response analysis sfra, the measurement techniques and interpretation of sfra measurement. Aug 29, 2014 in addition to the above transformer testing methods, the power transformer also goes through some other tests, performed on it, before the actual commissioning of the transformer at the site. Power transformer testing power transformer factory test using ieee standards waldemar ziomek cg power systems canada ieee training, houston, texas, oct. Dismantling a power transformer to determine its condition is hardly ever a practical possibility. Sweep frequency response analysis of power transformers typical test sequences 525024 issue 1 newtons4th ltd 30 loughborough rd mountsorrel loughborough le12 7at uk tel. Imports data from other fra test sets the frax series of sweep frequency response analyzers sfra detects potential mechanical and electrical problems that other methods are unable to detect. The sfra 5000 offers both high precision and portability in a single package, providing all the accessories required for fast, easy to use, reliable and repeatable measurements. Before we start testing, are there reasons to suspect the. Iec6007618 sfra of power transformers, typical test sequences this application note will discuss typical transformer configurations and measurement sequences as specified in the iec6007618 international standard. The role of sfra is growing in the transformer field and the results interpretation is becoming more and more important day by day. Transformer testing type tests and routine tests of. Sfra of on auto transformer generally, very large power transformers are auto transformers.
Sweep frequency response analyzer sfra measurements are now an established method for condition assessment of power transformers. If you measure the frequency response of a winding then you can identify winding movement. Frax99, frax101 and frax150 sweep frequency response. This is very reliable and sensitive method or tool for condition monitoring of the physical condition of transformer windings. The sweep frequency response analysis sfra is an analysis technique for detecting winding displacement and deformation among other mechanical and electrical failures on power and distribution transformers. The latest sfra test sets make these techniques more accessible, more convenient and more dependable that ever. Sfra testing basics offline test the transformer is seen as a complex impedance circuit open magnetization impedance and short shortcircuit impedance responses are measured over a wide frequency. Power transformers are critical components in an electrical power network.
Iec6007618 sfra of power transformers, typical test. Sfra testing basics offline test the transformer is seen as a complex impedance circuit open excitation current and short shortcircuit impedance responses are measured over a wide frequency range and the results are presented as magnitude response curves filter response changes in the impedance can be. 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. Sfra and the role it plays in transformer test and maintenance. Pdf interpretation of sweep frequency response analysis sfra. Sfra is condition monitoring technique for expensive power equipment. Sweep frequency response analysis capacitor transformer.
Power outages cause loss of income for power consumers and. The winding of transformer may be subjected to mechanical stress. May 15, 2016 sfra stands for sweep frequency response analysis. Sweep frequency response test in the most of the commercial sweep frequency response measuring instruments, the measuring task is. Deviations between frequency responses indicate mechanical andor electrical changes in the active part of a transformer. The m5400 reduces the uncertainty about apparatus condition by providing solid evidence of mechanical integrity or winding movement. Sweep frequency response analyzer sfra user guide doble engineering company 85 walnut street watertown, massachusetts 024724037 usa. A capacitive interwinding measurement describes a test between two. Use it to help determine how a transformer is deteriorating, if it can go back in service after a fault or if it has been damaged during transit. Sfra including what tests to perform, when to perform. Sfra is an offline testing and it can be carried out for any voltage rating of power transformer. Each frequency range corresponds to dfferent components in the transformer. Pdf interpretation of sweep frequency response analysis.
Frequency response analysis or sweep frequency response analysis sfra is a comparative test to evaluate the electromechanical condition of the transformer. The procedure of the transformer ratio test is simple. M5400 sweep frequency response analysis doble engineering co. Nowadays, there is an increasing interest in sfra method because of its sensibility in detecting mechanical faults without opening the unit. This ms excel spreadsheet is actually detailed instruction for each procedure necessary for correct testing of power transformer. No load losses at 60 hz and 50 hz failure localization shortcircuit impedance. The following tests are routinely conducted in the field on the transformer. Sweep frequency response analysis transformer applications. Power transformers are the central hub in the field of energy distribution and transmission. Fist facilities instructions, standards, and techniques fra frequency response analyses gm gram gsu generator step up h 2 hydrogen hz hertz cycles. For healthy transformers, the measured trace matches the reference sfra trace.
The fra test may be completed as an impulse response or as a sfra test. For new transformers in the factory, use the nominal detc position. Power transformer testing transformers may be tested using ac or dc voltage. Sfra is today an established technology to investigate the mechanical and electrical integrity of a transformer. Sfra testing basics offline test the transformer is seen as a complex impedance circuit open magnetization impedance and short shortcircuit impedance responses are measured over a wide frequency range and the results are presented as magnitude response curves filter response changes in the impedance. Kirubakaran2 research scholar 1, assistant professor2 abstract ower transformer is one of the most imperative equipments in a high voltage electric power system. M5200, m5300, or m5400 sweep frequency response analyzer. The latest sfra test sets make these techniques more accessible, more convenient and. Using the frequency response analysis fra in transformers internal fault detection jalal abdallah. Special consideration should be given to safety when testing a transformer without oil so that excessive voltages are not applied. Transformer service trafositetesting verify the reliability of your transformers abb transformer remanufacturing and engineering services tres proudly offers comprehensive onsite transformer testing services with our highvoltage mobile test system.
Sfra, detect of winding deformation in power transformer doi. File type pdf sweep frequency response analysis transformer applications sweep frequency response analysis transformer. Frequently asked sweep frequency response analysis questions. The acronym sfra is meaning sweep frequency response analysis. Testing, diagnostics and reliable condition assessment of power transformers becomes increasingly relevant due to the ageing of transformer fleets around the world. Use of frequency response analysis to detect transformer. Sweep frequency response analyzer sfra quick start guide.
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