{"id":10749,"date":"2026-08-29T23:43:19","date_gmt":"2026-08-29T15:43:19","guid":{"rendered":"https:\/\/q8bbzjnpm5.wpdns.site\/?p=10749"},"modified":"2026-08-29T23:43:19","modified_gmt":"2026-08-29T15:43:19","slug":"key-points-for-maintaining-power-transformers-unveiled","status":"publish","type":"post","link":"https:\/\/subian-electric.com\/pt\/news\/key-points-for-maintaining-power-transformers-unveiled\/","title":{"rendered":"Pontos-chave para a Manuten\u00e7\u00e3o de Transformadores de Pot\u00eancia Revelados"},"content":{"rendered":"<p>Um engenheiro est\u00e1 verificando o hist\u00f3rico de manuten\u00e7\u00e3o de um transformador elevador de 50 MVA que est\u00e1 em opera\u00e7\u00e3o h\u00e1 14 anos. O transformador ainda n\u00e3o enfrentou nenhuma falha maior, mas a \u00faltima an\u00e1lise de \u00f3leo mostra aumento nos n\u00edveis de hidrog\u00eanio e algumas amostras de \u00f3leo do OLTC precisam ser coletadas. Os engenheiros fixaram o or\u00e7amento anual para a manuten\u00e7\u00e3o do transformador e o transformador est\u00e1 prestes a ser utilizado na pr\u00f3xima parada, que \u00e9 de extrema import\u00e2ncia para o processo. Na realidade, \u00e9 claro que as tarefas devem ser priorizadas com base na efici\u00eancia de cada tarefa de acordo com o tempo em que a tarefa deve ser realizada e como cada tarefa deve ser analisada quanto \u00e0 sua efic\u00e1cia.<\/p>\n<p>Este artigo destaca os aspectos mais importantes do processo de manuten\u00e7\u00e3o de transformadores de pot\u00eancia que est\u00e3o ocultos em manuais extensos, a saber, quais tarefas realmente devem ser realizadas para garantir a confiabilidade do equipamento, o que os resultados da inspe\u00e7\u00e3o significam para a manuten\u00e7\u00e3o do transformador e quais tarefas podem ou n\u00e3o podem ser realizadas.<\/p>\n<blockquote><p>Resposta R\u00e1pida: A manuten\u00e7\u00e3o do transformador de pot\u00eancia pode proteger o equipamento por meio de: gerenciamento de \u00f3leo, testes el\u00e9tricos, manuten\u00e7\u00e3o de acess\u00f3rios e documenta\u00e7\u00e3o. Os par\u00e2metros centrais do gerenciamento incluem: a temperatura do \u00f3leo de 75 \u2013 85\u00b0C enquanto trabalha sob a carga nominal, umidade do \u00f3leo abaixo de 20 \u2013 30 ppm, tens\u00e3o de ruptura acima de 30 \u2013 40 kV e o TDCG inferior a 720 ppm de acordo com a IEEE C57.104. Os custos anuais de manuten\u00e7\u00e3o chegam a $1.500\u2013$5.000 por local.<\/p><\/blockquote>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10750\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/Key-Points-For-Maintaining-Power-Transformers-Unveiled.webp\" alt=\"Key Points For Maintaining Power Transformers Unveiled\" width=\"1448\" height=\"1086\" \/><\/p>\n<hr \/>\n<h2 id=\"why-maintenance\">Por que a Manuten\u00e7\u00e3o de Transformadores de Pot\u00eancia \u00e9 Inegoci\u00e1vel<\/h2>\n<p>O transformador de pot\u00eancia \u00e9, ao mesmo tempo, o equipamento mais caro, de maior durabilidade e menos redundante encontrado em muitas esta\u00e7\u00f5es de energia el\u00e9trica. Se um problema surgir com um transformador, a produ\u00e7\u00e3o ir\u00e1 parar, a planta ir\u00e1 desligar e levar\u00e1 alguns meses para adquirir um substituto em car\u00e1ter de emerg\u00eancia. De acordo com dados de confiabilidade fornecidos por grupos de trabalho da IEEE e CIGR\u00c9, quebras de isolamento, trocadores de tomadas e quebras de bucha s\u00e3o as principais fontes de falhas em transformadores; esses componentes podem ser identificados durante procedimentos de manuten\u00e7\u00e3o adequadamente designados que previnem a falha real de ocorrer.<\/p>\n<p>A justificativa econ\u00f4mica \u00e9 bastante simples. Por exemplo, um transformador de pot\u00eancia de 50MVA custa $250.000 e pode custar at\u00e9 $1,2 milh\u00f5es; ao mesmo tempo, seu custo anual de manuten\u00e7\u00e3o \u00e9 de $1.500 a $5.000, o que representa apenas uma pequena porcentagem do custo do equipamento. Al\u00e9m disso, paradas n\u00e3o planejadas s\u00e3o conhecidas por custar pelo menos $50.000 e podem chegar a $2 milh\u00f5es, dependendo da carga perdida e sua dura\u00e7\u00e3o. Assim, \u00e9 seguro dizer que \u00e9 prudente arcar com o custo da manuten\u00e7\u00e3o, pois \u00e9 o mais econ\u00f4mico em termos da magnitude das poss\u00edveis perdas.<\/p>\n<h2 id=\"pillars\">Os Quatro Pilares da Manuten\u00e7\u00e3o de Transformadores de Pot\u00eancia<\/h2>\n<p>No que diz respeito \u00e0 manuten\u00e7\u00e3o de transformadores refrigerados a \u00f3leo, ela se enquadra em uma das quatro \u00e1reas, que garantem que nada fique sem aten\u00e7\u00e3o e nada seja feito em excesso.<\/p>\n<table>\n<thead>\n<tr>\n<th>Pilar<\/th>\n<th>O que Abrange<\/th>\n<th>Teste Principal \/ Tarefa<\/th>\n<th>Capturas<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Gest\u00e3o de \u00f3leo e DGA<\/td>\n<td>Condi\u00e7\u00e3o do \u00f3leo isolante e gases dissolvidos<\/td>\n<td>DGA, umidade, tens\u00e3o de ruptura, acidez<\/td>\n<td>Falhas t\u00e9rmicas, arco el\u00e9trico, entrada de umidade, contamina\u00e7\u00e3o<\/td>\n<\/tr>\n<tr>\n<td>Testes el\u00e9tricos<\/td>\n<td>Integridade do enrolamento e isolamento<\/td>\n<td>Resist\u00eancia de isolamento, rela\u00e7\u00e3o, resist\u00eancia do enrolamento, corrente de magnetiza\u00e7\u00e3o<\/td>\n<td>Danos ao enrolamento, degrada\u00e7\u00e3o do isolamento<\/td>\n<\/tr>\n<tr>\n<td>Cuidado com acess\u00f3rios e componentes<\/td>\n<td>Buchas, respiradores, trocadores de tap, resfriamento, prote\u00e7\u00e3o<\/td>\n<td>Inspe\u00e7\u00e3o visual, teste de \u00f3leo OLTC, verifica\u00e7\u00e3o do respirador, teste do ventilador<\/td>\n<td>Desgaste mec\u00e2nico, umidade, falha de resfriamento<\/td>\n<\/tr>\n<tr>\n<td>Documenta\u00e7\u00e3o e tend\u00eancias<\/td>\n<td>Hist\u00f3rico, pontua\u00e7\u00e3o de condi\u00e7\u00e3o, classifica\u00e7\u00e3o de risco<\/td>\n<td>Livros de registro, CMMS, an\u00e1lise de tend\u00eancias<\/td>\n<td>Falhas de desenvolvimento lento perdidas por leituras \u00fanicas<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10751\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/The-Four-Pillars-of-Power-Transformer-Maintenance.webp\" alt=\"Os Quatro Pilares da Manuten\u00e7\u00e3o de Transformadores de Pot\u00eancia\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2 id=\"oil\">Pilar 1: Gest\u00e3o de \u00d3leo e DGA<\/h2>\n<p>O \u00f3leo atua como isolante e refrigerante no transformador e como uma ferramenta de diagn\u00f3stico para identificar as falhas dentro do equipamento. A an\u00e1lise de g\u00e1s dissolvido representa o teste mais abrangente que revela todas as informa\u00e7\u00f5es necess\u00e1rias. As falhas quebraram o isolamento de papel e \u00f3leo em gases espec\u00edficos dissolvidos no \u00f3leo, como hidrog\u00eanio, metano, etano, etileno, acetileno, CO e CO2. A interpreta\u00e7\u00e3o dos gases usando IEEE C57.104 e IEC 60599 indica o tipo e o n\u00edvel da falha.<\/p>\n<p>Valores importantes da gest\u00e3o de \u00f3leo em transformadores de pot\u00eancia:<\/p>\n<table>\n<thead>\n<tr>\n<th>Par\u00e2metro<\/th>\n<th>Normal<\/th>\n<th>Aviso<\/th>\n<th>A\u00e7\u00e3o<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Tens\u00e3o de ruptura do \u00f3leo<\/td>\n<td>&gt; 40\u201360 kV<\/td>\n<td>30\u201340 kV<\/td>\n<td>&lt; 30 kV: filtrar ou substituir o \u00f3leo<\/td>\n<\/tr>\n<tr>\n<td>Umidade do \u00f3leo<\/td>\n<td>&lt; 15\u201320 ppm<\/td>\n<td>20\u201330 ppm<\/td>\n<td>&gt; 30\u201340 ppm: secar e encontrar a fonte de entrada<\/td>\n<\/tr>\n<tr>\n<td>G\u00e1s combust\u00edvel total dissolvido<\/td>\n<td>&lt; 720 ppm<\/td>\n<td>720\u20131.920 ppm<\/td>\n<td>&gt; 1,920 ppm: investigar; &gt; 4,630 ppm: retirar de servi\u00e7o<\/td>\n<\/tr>\n<tr>\n<td>Acidez<\/td>\n<td>Baixa (n\u00famero de neutraliza\u00e7\u00e3o &lt; 0.1\u20130.15 mg KOH\/g)<\/td>\n<td>Tend\u00eancia crescente<\/td>\n<td>Alta: recondicionar o \u00f3leo<\/td>\n<\/tr>\n<tr>\n<td>Furan content<\/td>\n<td>Baixo<\/td>\n<td>Rising<\/td>\n<td>High: paper aging confirmed, plan end-of-life<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The practical scheduled maintenance for power transformers includes an annual DGA, and a semi-annual one for critical units or after a fault event. Since OLTC compartment oil ages faster, its oil is tested every 6-12 months.Always collect the sample from the same valve at a defined load and note down the temperature of the oil.<\/p>\n<h2 id=\"electrical\">Pillar 2: Electrical Testing<\/h2>\n<p>Electrical tests assist oil tests in inspecting the windings and insulation directly:<\/p>\n<ul>\n<li>Insulation resistance (megger): is assessed between winding to the ground and among the windings. Normal high-voltage winding\u2019s insulation resistance should show from 1000 to 5000 M\u03a9 or even more; comparison over the years is of greater importance than the numbers in absolute. If the numbers start dropping, there is a presence of moisture or pollution.<\/li>\n<li>Winding resistance: is measured phase by phase and compared; any variation above 2\u20133 percent indicates a fault either in a connection or turn.<\/li>\n<li>Turn ratio: is a winding ratio test confirming the results with the nameplate; a deviation above 0.5-1 percent indicates shorts in the windings.<\/li>\n<li>Magnetizing current: a rise in this current may indicate the short or damage in the core.<\/li>\n<\/ul>\n<p>These tests normally cost between $300 and $1,500 for a unit per inspection and are performed once a year or after some serious incident, such as short circuit or lightning strike. When joined with DGA, they can help to determine the problem: DGA informs us that there is a failure, while the tests indicate the location.<\/p>\n<h2 id=\"accessories\">Pillar 3: Accessory and Component Care<\/h2>\n<p>Accessories are known to malfunction more than the core transformer and failures can be avoided because they are predictable. The following table shows necessary tasks that should be performed and the costs associated with the repair:<\/p>\n<table>\n<thead>\n<tr>\n<th>Accessory<\/th>\n<th>Inspe\u00e7\u00e3o<\/th>\n<th>Interval<\/th>\n<th>Typical Cost<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Bushings<\/td>\n<td>Cracks, tracking, oil seepage; PD\/tan-delta for critical units<\/td>\n<td>Daily visual; PD every 3\u20136 yr<\/td>\n<td>$3,000\u2013$30,000 per phase to replace<\/td>\n<\/tr>\n<tr>\n<td>Desumidificador<\/td>\n<td>Silica gel color; regenerate when pink<\/td>\n<td>Daily check<\/td>\n<td>$50\u2013$300<\/td>\n<\/tr>\n<tr>\n<td>OLTC<\/td>\n<td>Oil sample, drive motor, contacts<\/td>\n<td>Oil 6\u201312 mo; overhaul 3\u20136 yr<\/td>\n<td>$5,000\u2013$40,000 per overhaul<\/td>\n<\/tr>\n<tr>\n<td>Cooling fans \/ pumps<\/td>\n<td>Operation, airflow, radiator fins<\/td>\n<td>Monthly test<\/td>\n<td>$300\u2013$5,000 per component<\/td>\n<\/tr>\n<tr>\n<td>Protection devices<\/td>\n<td>Buchholz and relief valve trip circuits<\/td>\n<td>During scheduled outages<\/td>\n<td>$200\u2013$1,000<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<ul>\n<li>Bushings: check for damages, cracks and oil leakages and insure that damaged units are quickly replaced. Bushing failure can destroy transformers and costs of replacement vary from $3,000 to $30,000. PD and tan-delta tests can be performed every 3-6 years for important bushings.<\/li>\n<li>Breather and conservator: silica gel should always be blue; if it is pink, it must be regenerated or replaced. When a breather is saturated, it allows moist air to penetrate into oil, which causes slow insulation degradation.<\/li>\n<li>Tap changer: for OLTC units, OLTC oil should be sampled regularly; tap change operation should be checked and motor current verified every 3-6 years. OLTC maintenance costs from $5,000 to $40,000 for one repair cycle but avoids major failures.<\/li>\n<li>Cooling system: fans, pumps and thermostats must be tested; radiator fins cleaned and oil flow monitored for failures.<\/li>\n<li>Protection devices: Buchholz relay, pressure protection devices and trip circuits should be tested during regular repairs.<\/li>\n<\/ul>\n<h2 id=\"documentation\">Pillar 4: Documentation and Trend Tracking<\/h2>\n<p>Data pertaining to maintenance is incredibly valuable, while documentation provides support for other essential components of the system. A key concept here is the practice of maintaining history for every unit of the system, containing results of commissioning tests, DGA performance and analysis, electrical tests, overload incidents, repairs and alarms. This history allows for three things: discovering patterns (e.g. a gas concentration increased from 40 to 120 ppm in 24 months), establishing the conditions (ordering the units per budget priorities), and proving the existence of warranty and insurance agreements.<\/p>\n<p>Most of the maintenance procedures today are automated by modern asset management systems. The minimum that should be done is keeping a logging book of all useful metrics: all readings, dates of events and actions of maintenance staff. Those companies that maintain the data gain advantages from it through getting money for justifying their budgets, helping audit regulation authorities, and speeding up root cause investigation of any issue.<\/p>\n<h2 id=\"schedule\">The Maintenance Schedule: Tasks and Frequencies<\/h2>\n<p>The schedule below contains a useful reference point for power transformers. It can be altered based on the urgency, age, and state of the transformer.<\/p>\n<table>\n<thead>\n<tr>\n<th>Frequ\u00eancia<\/th>\n<th>Task<\/th>\n<th>Typical Cost<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Daily<\/td>\n<td>Visual round: oil level, sound, temperature, bushings, leaks<\/td>\n<td>$300\u2013$1,500\/yr labor<\/td>\n<\/tr>\n<tr>\n<td>Quarterly<\/td>\n<td>Insulation resistance, OLTC visual\/functional check, fan test<\/td>\n<td>$200\u2013$800<\/td>\n<\/tr>\n<tr>\n<td>Semi-annual<\/td>\n<td>DGA for critical units, OLTC oil sample<\/td>\n<td>$200\u2013$500 per sample<\/td>\n<\/tr>\n<tr>\n<td>Annual<\/td>\n<td>Full DGA, oil quality package, winding resistance, ratio, megger<\/td>\n<td>$800\u2013$2,500<\/td>\n<\/tr>\n<tr>\n<td>Every 3\u20136 years<\/td>\n<td>OLTC overhaul, bushing PD\/tan-delta, protection test, thorough inspection<\/td>\n<td>$5,000\u2013$40,000<\/td>\n<\/tr>\n<tr>\n<td>Every 10\u201315 years<\/td>\n<td>Major overhaul, oil filtration\/replacement, gasket renewal<\/td>\n<td>$10,000\u2013$60,000<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>As a general rule, a DGA must be run anytime and following any unusual incident. In the case of such event happening, the DGA must be done immediately.<\/p>\n<h2 id=\"standards\">Key Standards for Maintenance Limits<\/h2>\n<p>Decisions regarding maintenance works must be based on the standards in place and not on hearsay. Here below is the list of the mandatory references in this field:<\/p>\n<ul>\n<li>IEEE C57.104 &#8211; the interpretation of partial discharge and its evaluation for oil-based diagnostics.<\/li>\n<li>IEC 60599 &#8211; an international guide for DGA analysis of old equipment.<\/li>\n<li>IEC 60422 &#8211; control and servicing of mineral insulating oils with quality indicators.<\/li>\n<li>IEC 60156 &#8211; test method for dielectric failure.<\/li>\n<li>IEC 60076-7 &#8211; recommendation regarding transformer loading and temperature limits.<\/li>\n<li>IEC 60270 \/ IEC 62478 &#8211; methods of partial discharge measurement in modern diagnostics.<\/li>\n<\/ul>\n<p>If the manufacturer&#8217;s instruction of a specific piece of equipment puts forward stricter or more specific limits, they should be adhered to.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10752\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/Key-Standards-for-Maintenance-Limits.webp\" alt=\"Key Standards for Maintenance Limits\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2 id=\"budget\">Budgeting Maintenance: Cost vs. Failure Risk<\/h2>\n<p>Maintenance budgets should be allocated according to risk and not based on experience or habits. Some principles are:<\/p>\n<table>\n<thead>\n<tr>\n<th>Item<\/th>\n<th>Valor T\u00edpico<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Annual maintenance program (per power transformer)<\/td>\n<td>$1.500\u2013$5.000<\/td>\n<\/tr>\n<tr>\n<td>DGA sample<\/td>\n<td>$200\u2013$500<\/td>\n<\/tr>\n<tr>\n<td>Oil quality package<\/td>\n<td>$150\u2013$400<\/td>\n<\/tr>\n<tr>\n<td>Online monitoring suite (critical units)<\/td>\n<td>$25,000\u2013$120,000 capital<\/td>\n<\/tr>\n<tr>\n<td>Transformer replacement (20\u201360 MVA)<\/td>\n<td>$250,000\u2013$1.2 million<\/td>\n<\/tr>\n<tr>\n<td>Unplanned outage cost<\/td>\n<td>$50,000\u2013$2 million per event<\/td>\n<\/tr>\n<tr>\n<td>Expected service life with proper maintenance<\/td>\n<td>30\u201340 years<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>It all comes down to math: a $400 per year DGA sample of a $500,000 asset for which you are getting 30+ years of service from is the least costly investment you make. The same reasoning applies to extending inspections for units in good condition and to increasing inspection frequency for riskier units.<\/p>\n<h2 id=\"modern\">Modern Maintenance Tools: Monitoring and Analytics<\/h2>\n<p>Monitoring and analytics are revolutionizing the maintenance discipline. With online DGA monitors, partial discharge sensors, and temperature\/load trackers in place, continuous data is made available for critical units, thanks to analytics platforms that transform the data into serious alarms. The economics call for a combination of methods: online monitors for the few critical units that would cause a catastrophic failure if one did occur, and the usual annual laboratory DGA for the major part. The standards-based threshold is unchanged, the only difference being that online monitoring systems get the fault that happens in between sampling the readings.<\/p>\n<p>However, expert interpretation remains essential. Data can lead to alarm fatigue or missed failures.<\/p>\n<h2 id=\"faq\">Perguntas Frequentes<\/h2>\n<h3>How often should a power transformer be maintained?<\/h3>\n<p>The basic principles behind power transformer maintenance include recurrent visual surveillance twofold, electrical checks occurring quarterly and DGA plus oil quality testing on an annual basis. Semestral DGA testing may be performed for the most critical devices, whereas online monitoring is also applicable; OLTC oil is tested almost once per year; major repairs take place once in five to ten years. In case of any abnormalities, an immediate testing must be conducted first.<\/p>\n<h3>What are the most important maintenance tests for a power transformer?<\/h3>\n<p>Dissolved gas analysis is considered the most useful single tests, because it enables to detect thermal and electrical problems before the catastrophe. It is usually used together with moisture and breakdown voltage tests, winding resistance and insulation tests, which makes five tests covering the majority of deterioration indicators.<\/p>\n<h3>How much does power transformer maintenance cost per year?<\/h3>\n<p>It costs around 1.500-5.000 dollars each year to implement the totally condition-based program for power transformers, including daily surveillance, DGA performed on an annual basis (costing 200-500 dollars), oil quality (150-400 dollars) and electrical testing (300-1.500). Major repairs cost should also be taken into consideration \u2013 they require 5.000-60.000 dollars once in five or ten years.<\/p>\n<h3>What is the normal service life of a maintained power transformer?<\/h3>\n<p>With disciplined oil management, suitable DGA monitoring, and regular electrical testing power transformers commonly serve for 30-40 years, some even reach 50. Insulation aging follows exponential relation with temperature: every 6-8 K of stable spot temperature above the design double insulation aging, which makes discipline loading to be a maintenance tool.<\/p>\n<h3>Can predictive maintenance prevent all transformer failures?<\/h3>\n<p>No, predictive maintenance helps to detect and prevent gradual failures (due to insulation, humidity, fracturing, oil contamination) that account for continuous defeats. However, bushing explosion, discharges and outside short-circuits cannot be predicted.<\/p>\n<h2 id=\"references\">Refer\u00eancias<\/h2>\n<ul>\n<li><a href=\"https:\/\/ieeexplore.ieee.org\/document\/9771388\" rel=\"nofollow noopener\" target=\"_blank\">IEEE C57.104: Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers<\/a> \u2014 The reference for DGA thresholds and maintenance response levels.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/633\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60422: Supervision and Maintenance Guidance for Mineral Insulating Oils<\/a> \u2014 Oil quality limits and maintenance practice for in-service transformers.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/352\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60599: Guide to the Interpretation of DGA in Mineral Oil-Impregnated Equipment<\/a> \u2014 International framework for gas interpretation in aged equipment.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/637\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60156: Insulating Liquids \u2014 Determination of the Breakdown Voltage<\/a> \u2014 Test standard for oil dielectric strength.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/632\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60076-7: Loading Guide for Oil-Immersed Power Transformers<\/a> \u2014 Temperature limits and loading guidance for oil-immersed units.<\/li>\n<li><a href=\"https:\/\/www.cigre.org\/\" rel=\"nofollow noopener\" target=\"_blank\">CIGR\u00c9<\/a> \u2014 Technical brochures on transformer maintenance, reliability, and condition assessment.<\/li>\n<li><a href=\"https:\/\/subian-electric.com\/pt\/\">Jiangsu Subian Electric Power<\/a> \u2014 IEC 60076-compliant transformer manufacturer providing maintenance documentation and technical support.<\/li>\n<\/ul>\n<h2 id=\"conclusion\">Conclus\u00e3o<\/h2>\n<p>The maintenance of power transformers should concentrate on quality service rather than mass production in the traditional sense of the word. The process of maintaining equipment revolves around four pillars: management of oil and DGA, electrical inspections, support maintenance, and documentation. The implementation of the process should ensure the use of asset to the maximum extent, the maintenance being cheap.<\/p>\n<ul>\n<li>Perform DGA tests once a year and after each troublesome situation.<\/li>\n<li>Conduct DGA simultaneously with oil and electrical tests.<\/li>\n<li>Maintain the discipline of accessory care: insulating bushing, breather, OLTC, and cooling system.<\/li>\n<li>Document and keep records.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>An engineer is checking the maintenance history of a 50 MVA step up transformer that is being in operation for 14 years. The transformer has not faced any major failure yet but the last oil analysis shows increase in levels of hydrogen and some samples of OLTC oil have to be taken. Engineers have fixed [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":10750,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[77],"tags":[],"class_list":["post-10749","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/posts\/10749","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/comments?post=10749"}],"version-history":[{"count":2,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/posts\/10749\/revisions"}],"predecessor-version":[{"id":10983,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/posts\/10749\/revisions\/10983"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/media\/10750"}],"wp:attachment":[{"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/media?parent=10749"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/categories?post=10749"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/subian-electric.com\/pt\/wp-json\/wp\/v2\/tags?post=10749"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}