The aim of this study was to find out the cause of distribution transformer failure and proffer solution to mitigate it. The failure analysis is conducted on 348 distribution transformers of various ratings and 11kv. The occurrence of unexpected failure can result in a lengthy downtime, with consequent loss of operating revenue. This failure puts business continuity at risk, according to the study.
Transformer manufacturers perform two main types of transformer testing type test of transformer and routine. Pdf distribution transformer failure analysis in gujarat. Pdf prevention of distribution transformer premature failures ijesrt journal academia. This paper investigates the impact of voltage imbalance on power distribution systems and equipment in various practical cases. Introduction transformer is a static machine with very high efficiency and rugged construction. The time delay for clearing this problem is only due to the lack of information. Transformer is a static machine with very high efficiency and rugged construction. 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.
Power transformer transfer of power distribution transformer transfer of power instrument transformer measurement and protection. Distribution system component failure rates and repair. The premature failure rate of distribution transformers is above 25% in some of the regions of the state of madhya pradesh m. Failure of a distribution transformer results to interruption of power supply to the consumers and involve high expenditure in repair or replacement of transformer. Nuregcr3122, potentially damaging failure modes of high. Pdf distribution transformer handbook oscar mayorquin. Pdf causes of transformer failures and diagnostic methods. National institute of technology, hamirpur hp india.
Dt failures have a major financial impact on both utility company and customers. This high failure rate is cause of concern to all the distribution companies discoms in the country. Reports say that every year distribution transformers worth rupees 200 crores fail. Therefore the reliability in power supply mainly depends on the reliable functioning of distribution transformer. Distribution transformer handbook is packed with practical information on transformer concepts, singlephase and threephase transformer connections, and procedures for installing overhead and padmount transformers.
If you mean what is the failure rate of the transformer as a part before it ends up in the product, it should be very, very low. Kenya power is the main distributor of electricity in kenya. The various types of transformer shown in the figure above are explained in detail below. Data about the transformer failure for the last 5 years was collected from pesco for two. Note the fused cutout and lighting arrestor combination external to the transformer.
Furan derivatives test, which uses software application once the oil is eligible for furan test. Distribution transformers are normally considered to be those transformers which provide the transformation from 11 kv and lower voltages down to the level of the final distribution network. That is, the highest failure rates are in the first few years. An analysis of international transformer failures, part 2 introduction. It has installed around 59000 nos distribution transformers in network. Practical approach for detection of failure of distribution transformers and their remidies. Transformer failure is a concern for more than 80 percent of industry professionals surveyed for the recent midel transformer risk report. Disclaimer the authors have done their best in providing an overview of the available information sources, published during the period 19932003, on distribution system component failure.
Bushes are insulating devices that insulate a high voltage electrical conductor to pass through an earth conductor. Abstract distribution transformer is an essential link in the distribution system. Distribution transformer is an electrical isolation transformer which converts highvoltage energy to lower voltage degrees appropriate for use in houses and business enterprise. This can be caused by thermal degradation over the life of the transformer, by thermal degradation due to excessive or frequent fault current, or by dielectric. Prediction model for the distribution transformer failure. Distribution transformer failure analysis is conducted to find out distribution transformer failure modes and causes, in a city based subdivision area of punjab state power corporation pspcl. The utility companies invest large funds annually for maintenance of distribution transformers.
The three methods are conventional oil test, furan derivatives test, and markov models. The rate of failure of distribution transformers in india is higher 1217% as compared to developed countries 23%. Two coefficients are fitted to our failure data, then, the pofcan be calculated for any age power transformer. Practical approach for detection of failure of distribution. Different investigations and test analyses have been conducted to identify the root causes of failure of the transformer in the power system, and to identify the preventive measures to avoid these breakdowns. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf.
Transformer testing type tests and routine tests of. Abb is a global leader in transformer technologies that enable. They also help maintain power quality and control, and facilitate electrical networks. Other causes of distribution transformer failure modes can be the result of a grounded core or core clamping structures such as throughbolts that develop shorts. Six in 10 respondents had experienced transformer failure in the last five years, and five in 10 said transformer failure would. End user distribution utility company what is distribution transformer failure. Failure rate of distribution transformers in india. Transformer protection application guide this guide focuses primarily on application of protective relays for the protection of power transformers, with an emphasis on the most prevalent protection schemes and transformers. A study of the root causes of high failure rate of distribution. Pdf analysis of distribution transformers failures was carried out in ughelli business unit in delta state under the benin electricity. When determining the cause of failure, the age of the transformer is critical information for narrowing down the list of potential issues. Some tests are done at a transformer manufacturer premises before delivering the transformer. The premature failure rate of distribution transformers is above 25% in some of the regions of. Introduction to the weibull distribution two coefficients are fitted to our failure data, then, the pofcan be calculated for any age power transformer.
Circle data analysis so for more analysis we have taken sample from the different. Also there is detailed analysis about the consisting of a distribution transformer. New hi parameters, an age distribution and logistic regression model were determined, enabling a higher accuracy in predicting failure events and can therefore be utilized in various asset management initiatives and risk mitigation. Power transformer is a very expensive equipment and plays a vital role in the electrical power transmission and distribution network. Analysis of transformer failures imia 2003 5 overloading this category pertains to those cases where actual overloading could be established as the cause of the failure. Transformer fuse operations are the most common equipment failure on distribution systems, comprising as much as 40% in one study 4. Data collected over the period 20112015 on the distribution network were simulated on etap software using the newtonraphson nr. In our previous discussion of a fiveyear international study of loss trends for transformer failures, we concluded that insulation failure was the leading cause. The rate of failure of distribution transformers in india is higher. When failure is confirmed, then onsite investigation and testing is conducted to collect vital data from site. Abstractdistribution transformer is an essential link in the distribution system.
Distribution transformer handbook alexander publications. Different investigations and test analyses have been conducted to identify the root causes of failure of. 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. In transformers it provides a current path through the tank wall.
Pdf distribution transformer failure analysis in gujarat discom. Analysis of transformer loadings and failure rate in onitsha. This study investigated transformer loadings and failure rate in the onitsha electricity distribution network by using the electrical transient analysis program etap software 12. This proposed idea will detect the fuse failure and intimate the concern persons at that instant using lab view software and messaging system incorporated in distribution transformer. The risk of a transformer failure is actually twodimensional, the frequency of failure and the severity of failure. Eventful transformer failures eventful transformer failures describe a tank failure where the tank is visibly damaged due to an internal fault. An analysis of transformer failures, part 2 causes. A distribution transformer or service transformer is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer. Among the materials consulted while preparing this book are.
An analysis of international transformer failures, part 2. We then run a monte carlo simulation using this distribution across a. 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. For confirming the specifications and performances of an electrical power transformer it has to go through a number of testing procedures. Also information about some types of transformers are gathered as well as distribution transformer connections installations.
Gsm based distribution transformer monitoring system bhakare govind a. Jul 29, 2014 it completely depends on the design it lands in. In distribution side transformers there are commonly two. That is, the highest failure rates are in the first few years of service and then decline. The foundation necessary for the installation of a. The invention of a practical efficient transformer made ac power distribution feasible. Transformer lifetime prediction stanford university. The cumulative distribution function cdf shows the proportion of assets which have failed. Transformer design drytype and cast resin, protection methods are being referred and more also included in the specific research document. At any time step, we can predict the probability of failure of the transformer in some set amount of timesteps. Introduction the distribution transformer dt is a vital link in the chain of power apparatus supplying electric power to the customers. A distribution transformer is one of major electrical equipment that links the.
The definition of voltage imbalance is introduced first, followed by description of the origins of voltage imbalance, and finally simulation results and discussion of the impact of. Failure of distribution transformers causes capital loss and loss of revenue to the nation. Product guide ret615 transformer protection and control. Keywords transformer failure, insulation failure, harmonics, power quality pq, distribution transformers. Identification of causes of distribution transformer failures and. Data on each generic type of equipment were analyzed to determine. Distribution transformer failure analysis in gujarat discom. Nov 19, 2018 other causes of distribution transformer failure modes can be the result of a grounded core or core clamping structures such as throughbolts that develop shorts. If the transformer in question is relatively old 1520 years, the damage may well be due to normal wear and tear.
This paper presents distribution transformer failure analysis to find out causes of failures responsible for very high rate of failure in a state owned electric utility punjab state power corporation limited pspcl in india. But, as i already stated in some of the earlier technical articles, transformer failures can cause a huge problem in power system, since its one of the most critical link and it can take a while to replace if it fails. Basics, maintenance, and diagnostics vii contents continued page 4. Generally speaking, the transformer requires less care compared to other electrical equipment. The damage may cause no significant impact, aside from the need to replace the tank, or it could be catastrophic. Some of the most commonly occurring failures of the transformer and their causes are listed below.
The software gives the corresponding reading about the present health of distribution transformer and thus the performance can be known, the output of which gives failure. These result in a shorted turn the core and produce high currents which are often detected by dissolved gas analysis. Distribution transformer failure modes, effects and. Rootcause analysis of transformer failure scenario at power. At present about 28204 distribution transformers of. Distribution transformers always have the potential for. There must be no gaps between the cabinet and the pad, otherwise the tamper resistance of the transformer is compromised. The distribution transformer dt is a vital link in the chain of power apparatus supplying electric power to the customers. Failure to comply may result in serious personal injury or damage to the equipment.
In the uk this was, until january 1995, 415 v threephase and 240 v phase to neutral. Setting procedures are only discussed in a general nature in the material to follow. The failure rate of distribution transformers in india is as high as 25 to 30% which is the highest in the world. Description ret615 is a dedicated transformer protection and control relay for power transformers, unit and stepup transformers including power generatortransformer blocks in utility and industry power distribution systems. Analysis of transformer loadings and failure rate in. Distribution transformer is an essential link in the distribution system. Types of transformer different types of transformer. Pdf failure analysis of distribution transformers a case. Distribution system component failure rates and repair times. Premature failure of distribution transformers a case study. New niyantra 20 distribution transformer fuse failure.
Pdf failure analysis of distribution transformers a case study. Additional security measures added to the percentage differential is also presented to enhance transformer differential security against defective primary equipment such as defective cts or ct wiring. The top 3 reasons for transformer failures machine design. Distribution transformer failures follow a bathtub curve. Distribution transformer failure affects the reliability and power quality of the supply system. Case studies of the impact of voltage imbalance on power. Transformer and cable failure rates published during the recent decade indicate somewhat lower values than the suggested values in reference bollen 1993. A distribution system carries power from substation transformer through feeder circuit to distribution transformer. The constant can be thought of as representing the risk of failure by causes that are independent of age or random events such as lightning, vandalism etc. Analysis of power transf failure in trans utilities 15.