Analysis of transformer failure in nagpur zone of msetcl nagpur zone has total of 72 ehv. Investigation into current transformer failures within eskom distribution deepak rampersad in partial fulfilment of the requirements for the degree master of science in power and energy systems, faculty of engineering, university of kwazulunatal december 2010 supervisor. For the failures reported, the leading cause of transformer failures is insulation failure. Modern transformers are designed to closer tolerances than transformers in the past.
Before conducting the onsite investigation, documents related to the history of. This category includes inadequate or defective installation, insulation deterioration, and short. Reasons for transformer failures, distribution transformer. An analysis of international transformer failures, part 2 introduction. Distribution transformer failure modes, effects and criticality analysis. Transformer failure analysis find out what caused a. Failure to comply may result in serious personal injury or damage to the equipment. Rootcause analysis of transformer failure scenario at. Trend of transformer failures in the ashanti east region fig3. The high current seen at the device junction displays a typical failure mechanism. It is thus very important to avoid transformer failure.
Causes, prevention, and maximum service life introduction over the years, hartford steam boiler has investigated thousands of transformer failures, compiling an extensive database of loss information. We do this by fitting the deviations from the model to a generalized extreme value. The transformer has served useful life for 8 years only i. A statistical approach to processing power transformer failure data conference paper pdf available january 2007 with 1,291 reads how we measure reads. Data separation the failure records of power transformer are separated depending region, location, type, size, accessory parts and other historical usage data. Pdf analysis of distribution transformers failures was carried out in ughelli business unit in delta state under the benin electricity. What is distribution transformer, electrical isolation. As you are aware, the distribution sector has a large number of distribution transformers of several capacities. Practical approach for detection of failure of distribution. The different failure modes that can take place in a power transformer can have different origins.
However, the operating conditions in the moment of the failure, the inspection records of the relays of protection of the various parts, as well as the transformer maintenance and the regular inspection, will help to detect the cause in many occasions. New niyantra 20 distribution transformer fuse failure detection and information passing system by shankar. Eventful transformer failures eventful transformer failures describe a tank failure where the tank is visibly damaged due to an internal fault. An external fusecutout combination is mounted between the distribution primary and the conventional transformer. Transformer with lv side fused with copper links projection proceedings of the world congress on engineering 2010 vol ii wce 2010, june 30 july 2. We expect an endless supply, and usually we have it. International organization of scientific research 43 p a g e the distribution transformer is static equipment and is used to either step down or step up the voltage as the case may be. Transformer failures produced by the causes mentioned above, create secondary failures and of a third type, hindering their tracking. It depends upon the voltage which has been shortcircuited and upon the. Reliability and vulnerability of transformers for electricity. Reliability and vulnerability of transformers for electricity transmission and distribution keywords critical infrastructure, transformer, reliability, ageing, blackouts abstract in the last years the failure frequency of transformers increased, e. Padmounted transformers are used with underground systems. This is the only reason which possibly attributed to the failure of the transformer due to insulation failure.
Agerelated failures figure 1 is based on the survival tables for men for the year 2007 as published by statistics netherlands. For the love of physics walter lewin may 16, 2011 duration. Power input to a transformer is not all delivered to the secondary load. Electric utilities should have a sufficient number of spare transformers to backup substation distribution transformers to replace transformers that fail and. Practical approach for detection of failure of distribution transformers and their remidies. The tap changer function in the transformer is to regulate the voltage level. Basics, maintenance, and diagnostics vii contents continued page 4. An analysis of international transformer failures, part 2. The transformer should be protected from the faults to avoid break down of the transformer which may lead to major interruption in power transformation. Transformer losses and impact on first cost background by doe mandate, effective january, 2010 all oilfilled distribution transformers manufactured in the u. The foundation necessary for the installation of a. Distribution transformers always have the potential for eventful failure. The fuse holder works in conjunction with abb doiii fuse links which can be found on page 6 of this guide. Below are some specific recommendations which transformer users should consider, in order to reduce the possibility of failure for offshore applications.
Adequate space should be provided around the transformer for access and ventilation. Request pdf distribution transformer failure modes, effects and criticality analysis fmeca distribution transformer is a most important. For oil filled distribution transformers, the european standard en 504641 includes. Durabil is a single layer of epoxy powder deposited electrostatically and baked on a strap conductor. The premature failure rate of distribution transformers is above 25% in some of the regions of the state of madhya pradesh m. The high rate of failure of secondary distribution transformer in power systems may perhaps be described as 0ne of the tragedies of distribution system management of present times especially in developing countries like india. Distribution transformers are costly and critical equipments in electricity distribution network.
An investigation into protection integrity of distribution. Multiplying this reference load by values in a range of e. Distribution and power transformers tasks 1 7 eceee. Failure of distribution transformers causes capital loss and loss of revenue to the nation. However, the various techniques for internal fault identification include refusing, and if the transformer is faulted a fuse operation itself is a dramatic event for the line worker, just less so than a full transformer failure. Again, in the event of this illegal connection of power from the distribution low tension lines due to power failure or outage from one streetroad tend to cause under voltage or over voltage as the case may be. Failure investigation consists of many steps in accurate sequence to conclude a significant outcome for transformer failure.
The two primary enemies of power transformers are transient overvoltages and heat. Pdf failure analysis of distribution transformers a case study. Management system of distribution transformer loading. Data of failure analysis of power transformer is selected from the sample transformers of 11522 kv and 23011522 kv system voltage by considering the quality and quality of recorded data. Sep 08, 2015 transformer failure modes the failure of a power transformer is almost always a catastrophic event that will cause the system to fail. The doiii fuse holder is designed for use at voltages up to 23 kv linetoground and 150 kv bil. A statistical approach to processing power transformer. The short circuit may occur in two or three phases of electrical power system. Substation distribution transformers failures and spares ieee xplore. The advent of csp technology has encouraged progressive manifactures to go in for high performance distribution transforms which mitigate the operation and. Introduction he development in sensor, communication, computer, and. A distribution transformer s function is straightforward.
The result of a electrical failure can be a turn to turn failure. Also there is detailed analysis about the consisting of a distribution transformer. Bayesian analysis of power transformer failure rate based on. Offline smps failure modes pwm switchers and dcdc converters 5 this is the common failure mode for a bipolar transistor pn junction during a shortload event.
Analysis of failure statistics and history test record for. Inside the transformer paper insulators are used which are surrounded by oil that provides further insulation. Distribution transformer is an electrical isolation transformer which convert highvoltage electricity to lower voltage levels acceptable for use in homes and business. The process is closely controlled and monitored to ensure a continuous, uniform coating. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Specify most suitable transformer, when all factors have been considered 1. Distribution transformer failure analysis in gujarat. A transformer has no moving parts and is a completely static solid state device, which insures, under normal operating conditions, a long and troublefree life. Transformer causes of failures the fault that most frequently occur in practice may be classified broadly as follows, although to a large extent the different kinds often react upon one another. Even the smallest fault results in the wrong power output 6. It is important to note that overloads rarely result in transformer failures, but do cause thermal aging of winding insulation. Oct 03, 2017 issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online.
A ventilation of about 4 cubic meters of airminute per kw loss of the transformer should be obtained. Pdf a statistical approach to processing power transformer. Failure is when the transformer was scrapped after the. Transformer failure in msetcl during 0809,0910 and upto june 10 21 21. Transformer design drytype and cast resin, protection methods are being referred and more also included in the specific research document.
Performance test of faulty distribution transformers along. The risk of a transformer failure is actually twodimensional. Analysis of power transf failure in trans utilities 15. The damage may cause no significant impact, aside from the need to replace the tank, or it could be catastrophic. Indeed, it will surely cause a transformer failure in due course. By means of statistical failure analysis the ageing processes related to the ages of the transformers can be shown. Failure is when the transformer was scrapped after the fault nonrepairable, catastrophic failure is when either an explosion or fire occurred. A distribution transformers function is straightforward.
The ceylon electricity board ceb has nearly 24,500 number of. The repaired transformer should be despatched only after the inspection is conducted and. In transformers it provides a current path through the tank wall. External and internal faults in transformer electrical4u. This project gives solution to the problems like fuse failure maintenance, giving protection to the transformer by authorized usage, power factor correction and harmonic suppression in the load side. In our previous discussion of a fiveyear international study of loss trends for transformer failures, we concluded that insulation failure was the leading cause. It reduces the most prevalent cause of transformer failure deterioration of turn insulation. The 315 mva 40022033 kv transformer burst into flames and was totally damaged. It is the most complex part of the transformer and also an important one. Bushes are insulating devices that insulate a high voltage electrical conductor to pass through an earth conductor.
Tertiary winding terminals taken out of the tank of transformer to avoid short circuiting. It is essential to protect high capacity transformers against external and internal electrical faults external faults in power transformer external short circuit of power transformer. Also information about some types of transformers are gathered as well as distribution transformer connections installations. Thus, effective, regular maintenance and testing is even more essential to. Agewise transformer failure details in msetcl in recent past. In this article, the author will discuss an updated model for transformer failure predictions in the coming decade and shares the observations of industry executives about the condition of the transformer marketplace. Minimize the failures of distribution transformer seminar.
This is done by either adding or removing turns from the secondary transformer winding. In the leading power crisis, power supplied to the people is only for few hours and when the fuse failure is not cleared quickly, peoples cannot. At work and at home, we are dependent on the power grid, a fact that is easy to overlook until the lights suddenly go out or the air conditioning stops or the production equipment quietly. Sep 24, 2017 for the love of physics walter lewin may 16, 2011 duration. At any time step, we can predict the probability of failure of the transformer in some set amount of timesteps.
We illustrate our approach via some real transformer condition data. Identification of causes of distribution transformer failures and. Any failure of these transformers is bound to cause great inconvenience to the consumers and huge financial losses to the utilities. Faults in the transformer are classified as internal faults and through faults. Distribution transformer is an essential link in the distribution system. Transformer failure modes the failure of a power transformer is almost always a catastrophic event that will cause the system to fail. The consequences can be arc from the energized winding to an adjacent winding or to ground. Bayesian analysis of power transformer failure rate based. Transformer lifetime prediction stanford university. An analysis of transformer failures, part 2 causes. If ageing can be denoted as the main cause for failure, the question then becomes to what extent ageing occurs. During this overcurrent, the junction depletion regions grow so large that the majority carriers.
Figure 1 is a scatter plot, or sometimes referred to as an fn curve. Rootcause analysis of transformer failure scenario at power. To protect it from the fault the typical faults in the fault should be known. Oilimmersed distribution transformers types cspcompletely selfprotected cpcurrent protected sconventional sbshovel special braced 3 to 167 kva 15,000 volts or less singleand threephase westinghouse electric corporation sharon, pa. A metering potential transformer mpt failure of december 17, 2010 was also analyzed. Keywordstransmission equipment, condition monitoring, maintenance optimization, power transformer failure rate, bayesian analysis. Reference 1 many district transformer designs already meet the doe requirements. Transformer failures can be expensive but replacement or repair costs are usually small compared to the cost of downtime. The process is repeated until the transformer dp reaches the point of failure. Easily share your publications and get them in front of issuus. There must be no gaps between the cabinet and the pad, otherwise the tamper resistance of the transformer is compromised. Repair and maintenance practice frequency of repair and failure, spare parts. Offline smps failure modes pwm switchers and dcdc converters. For investigation purpose, we accept ieee standard c57.
92 786 1322 221 16 464 564 388 414 997 1437 89 837 155 28 1221 1363 1343 418 1244 1350 60 1211 848 1351 475 359 306 432 1001