{"id":10835,"date":"2026-08-29T23:43:12","date_gmt":"2026-08-29T15:43:12","guid":{"rendered":"https:\/\/q8bbzjnpm5.wpdns.site\/?p=10835"},"modified":"2026-08-29T23:43:12","modified_gmt":"2026-08-29T15:43:12","slug":"prefabricated-transformer-a-versatile-and-convenient-solution-for","status":"publish","type":"post","link":"https:\/\/subian-electric.com\/es\/news\/prefabricated-transformer-a-versatile-and-convenient-solution-for\/","title":{"rendered":"Transformador Prefabricado: Una Soluci\u00f3n Vers\u00e1til y Conveniente para el Suministro de Energ\u00eda"},"content":{"rendered":"<p>Es martes por la ma\u00f1ana en un parque industrial de tama\u00f1o mediano cerca de Nairobi, y el equipo de electricidad solo tiene una semana para conectar una nueva planta de producci\u00f3n de calzado que fue conectada hace ocho d\u00edas. Nadie en el sitio de construcci\u00f3n est\u00e1 haciendo una plataforma para transformadores o esperando un recinto de ladrillo; en su lugar, una gr\u00faa est\u00e1 levantando una unidad de transformador lista del remolque y coloc\u00e1ndola en el suelo de concreto plano alrededor de las 10 a.m.; la conexi\u00f3n se termina al d\u00eda siguiente, y la f\u00e1brica comienza la primera producci\u00f3n el lunes siguiente. Tales actividades son ahora muy comunes en \u00c1frica, Asia y Am\u00e9rica del Sur, donde la electrificaci\u00f3n toma solo d\u00edas en lugar de meses.<\/p>\n<p>Este art\u00edculo ofrece una gu\u00eda pr\u00e1ctica sobre transformadores personalizados, de qu\u00e9 est\u00e1n hechos, c\u00f3mo se dise\u00f1an y prueban, cu\u00e1nto cuestan y c\u00f3mo evitar errores t\u00edpicos al comprarlos.<\/p>\n<blockquote><p>En pocas palabras, el transformador prefabricado, a veces llamado subestaci\u00f3n de transformador prefabricado, subestaci\u00f3n en caja o subestaci\u00f3n compacta, es la soluci\u00f3n que consiste en un transformador de potencia, equipos de conmutaci\u00f3n de media tensi\u00f3n, equipos de conmutaci\u00f3n de baja tensi\u00f3n, medidor y protecci\u00f3n dentro de una \u00fanica unidad compacta que es capaz de funcionar en condiciones exteriores. Se ensambla en la f\u00e1brica y se prueba por calidad antes de ser enviado al usuario final y colocado en la ubicaci\u00f3n requerida en un plazo de 2 a 5 d\u00edas.<\/p><\/blockquote>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10836\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/Prefabricated-Transformer-A-Versatile-And-Convenient-Solution-For.webp\" alt=\"Prefabricated Transformer A Versatile And Convenient Solution For\" width=\"1448\" height=\"1086\" \/><\/p>\n<hr \/>\n<h2 id=\"what\">\u00bfQu\u00e9 es un transformador prefabricado?<\/h2>\n<p>El transformador prefabricado es una subestaci\u00f3n de transformador completa que sale de la f\u00e1brica como un ensamblaje probado en lugar de como piezas sueltas. El t\u00e9rmino \u201cprefabricado\u201d se refiere al tipo de fabricaci\u00f3n: el recinto, transformador, interruptores, cables y sistemas auxiliares est\u00e1n dise\u00f1ados y ensamblados en la f\u00e1brica de tal manera que, al ser llevados al sitio, el producto resultante se puede conectar f\u00e1cilmente a un sistema el\u00e9ctrico existente.<\/p>\n<p>Este tipo de equipo se denomina IEC 62271-202 en Europa y otros pa\u00edses de exportaci\u00f3n (Equipos de Conmutaci\u00f3n y Control de Alta Tensi\u00f3n: Parte 202: Subestaci\u00f3n Prefabricada de Alta Tensi\u00f3n\/Baja Tensi\u00f3n). En Am\u00e9rica del Norte, el dispositivo equivalente a nivel de distribuci\u00f3n se llama com\u00fanmente transformador montado en base (IEEE C57.12.27). En China, este tipo de equipo se suele denominar transformador tipo caja o, en otras palabras, transformador tipo caja al estilo americano. As\u00ed, la denominaci\u00f3n de este equipo var\u00eda de un pa\u00eds a otro, pero la misma idea se implementa casi en todas partes al tener el equipo de transformador montado en el suelo compacto construido de la misma manera.<\/p>\n<p>En t\u00e9rminos pr\u00e1cticos, esta diferencia significa que el transformador tradicional necesita obras de construcci\u00f3n civil, edificios, una empresa separada para trabajos de instalaci\u00f3n y semanas de coordinaci\u00f3n antes de que comience a operar, mientras que el transformador prefabricado solo necesita una losa de concreto, una gr\u00faa y varios d\u00edas de trabajos el\u00e9ctricos.<\/p>\n<h2 id=\"components\">Componentes principales dentro de la unidad<\/h2>\n<p>Mientras que el fabricante y las clasificaciones determinan los modelos de cada transformador prefabricado, generalmente un transformador completamente ensamblado consta de tres a cuatro componentes funcionales, todos colocados en una carcasa de pl\u00e1stico reforzado con fibra de vidrio, que tiene un ancho promedio de 2.4-3.0 m y una longitud de 4-12 m.<\/p>\n<table>\n<thead>\n<tr>\n<th>Compartimento<\/th>\n<th>Equipos principales<\/th>\n<th>Clasificaci\u00f3n t\u00edpica<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Compartimento de media tensi\u00f3n<\/td>\n<td>RMU (unidad de anillo), interruptores SF6 o de vac\u00edo, caja de cables, rel\u00e9s de protecci\u00f3n<\/td>\n<td>12\u201340.5 kV, 400\u2013630 A barra colectora<\/td>\n<\/tr>\n<tr>\n<td>Compartimento del transformador<\/td>\n<td>Transformador sumergido en aceite o tipo seco, contenci\u00f3n de aceite, control de temperatura, ventilaci\u00f3n<\/td>\n<td>50\u20132,500 kVA<\/td>\n<\/tr>\n<tr>\n<td>Compartimento de baja tensi\u00f3n<\/td>\n<td>Tablero de baja tensi\u00f3n, alimentadores de salida, medici\u00f3n, banco de capacitores (opcional), pararrayos<\/td>\n<td>400 V \/ 690 V, hasta 4,000 A<\/td>\n<\/tr>\n<tr>\n<td>Sistemas auxiliares<\/td>\n<td>Calentadores, iluminaci\u00f3n, control de anti-condensaci\u00f3n, barra colectora de tierra, interbloqueos de puerta<\/td>\n<td>\u2014<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Tres caracter\u00edsticas distintivas separan las unidades confiables de sus contrapartes deficientes: un sumidero de aceite debajo del transformador para gestionar cualquier fuga; ventilaciones filtradas de aire, que han sido dise\u00f1adas de acuerdo con las normas IP54; y una base galvanizada en caliente elevada al menos 500-800 mm sobre el nivel del suelo.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10837\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/Core-Components-Inside-the-Unit.webp\" alt=\"Componentes principales dentro de la unidad\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2 id=\"how\">C\u00f3mo Funciona un Transformador Prefabricado<\/h2>\n<p>El m\u00e9todo de operaci\u00f3n de esta unidad es similar al de cualquier transformador de distribuci\u00f3n, pero en este caso, la unidad est\u00e1 construida en un dise\u00f1o diferente. La alimentaci\u00f3n de media tensi\u00f3n entra en la RMU, donde se conmutan y protegen de fallos de la l\u00ednea anular o radial entrante. Despu\u00e9s de eso, la alimentaci\u00f3n se transmite al transformador, que disminuye la tensi\u00f3n de 11 kV, 22 kV o 33 kV a niveles trif\u00e1sicos de 400V adecuados para los consumidores. Luego, el tablero de baja tensi\u00f3n distribuye la energ\u00eda a los circuitos de alimentadores de salida que est\u00e1n protegidos por MCCBs o ACBs, la medici\u00f3n da cr\u00e9ditos por la energ\u00eda consumida.<\/p>\n<p>La diferencia de esta versi\u00f3n prefabricada de una est\u00e1ndar es su ingenier\u00eda t\u00e9rmica. El transformador produce calor dependiendo de su carga y, por lo tanto, est\u00e1 encerrado dentro de una caja, que protege al transformador de los efectos del clima y previene el flujo de aire. IEC 62271-202 establece que las pruebas deben realizarse con la carcasa completa del transformador en lugar de realizar una prueba de transformador desnudo. Un buen dise\u00f1o de fabricaci\u00f3n debe proporcionar circulaci\u00f3n de aire utilizando rejillas de entrada y salida.<\/p>\n<h2 id=\"types\">Tipos y Configuraciones<\/h2>\n<div>Los transformadores prefabricados se clasifican por montaje, material de la carcasa y tecnolog\u00eda de interruptores:<\/div>\n<div><\/div>\n<table>\n<thead>\n<tr>\n<th>Clasificaci\u00f3n<\/th>\n<th>Variantes<\/th>\n<th>Uso T\u00edpico<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Montaje<\/td>\n<td>Montados en el suelo\/pad, montados en postes (unidades mini), montados en patines<\/td>\n<td>Distribuci\u00f3n a nivel del suelo; unidades mini para energ\u00eda rural y temporal<\/td>\n<\/tr>\n<tr>\n<td>Recinto<\/td>\n<td>Acero al carbono pintado, acero inoxidable, GRP\/composite<\/td>\n<td>Acero inoxidable\/composite para entornos costeros y corrosivos<\/td>\n<\/tr>\n<tr>\n<td>Transformador<\/td>\n<td>Sumergido en aceite (ONAN), tipo seco (resina fundida)<\/td>\n<td>Aceite para uso general; tipo seco para sitios sensibles al fuego o interiores<\/td>\n<\/tr>\n<tr>\n<td>Interruptores de media tensi\u00f3n<\/td>\n<td>RMU (aislado con SF6, aislado s\u00f3lido o aislado por aire), interruptor de carga, interruptor de circuito de vac\u00edo<\/td>\n<td>RMU para redes en bucle; interruptor para grandes alimentaciones industriales individuales<\/td>\n<\/tr>\n<tr>\n<td>Configuraci\u00f3n<\/td>\n<td>Dise\u00f1o de unidad \u00fanica, disposici\u00f3n en t\u00e1ndem\/dividida, subestaci\u00f3n mini<\/td>\n<td>Se adapta a la huella del sitio y disposici\u00f3n de carga<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>En relaci\u00f3n con las granjas solares y e\u00f3licas, la nueva configuraci\u00f3n de la subestaci\u00f3n solar integra la unidad MV\/LV con el equipo del lado del inversor y com\u00fanmente incluye un transformador elevador con una clasificaci\u00f3n entre 2500 y 4000 kVA por unidad. Este \u00faltimo tipo se ofrece generalmente como una plataforma montada sobre patines para su colocaci\u00f3n cerca de la estaci\u00f3n del inversor en el arreglo.<\/p>\n<h2 id=\"benefits\">Por qu\u00e9 los compradores eligen prefabricados sobre construidos en el sitio<\/h2>\n<ul>\n<li>Velocidad: La instalaci\u00f3n y puesta en marcha pueden tardar de 2 a 5 d\u00edas en lugar del per\u00edodo de construcci\u00f3n convencional de 4 a 12 semanas, lo cual es crucial en proyectos de ejecuci\u00f3n r\u00e1pida.<\/li>\n<li>Costo: La ausencia de instalaciones en el sitio, muchos contratistas y largos trabajos civiles generalmente significa que el costo total instalado disminuye entre el 20% y el 40% del costo del equipo convencional.<\/li>\n<li>Calidad: De acuerdo con las normas IEC 62271-202, cada unidad completa se somete a pruebas para verificar sus capacidades t\u00e9rmicas, diel\u00e9ctricas y de cortocircuito.<\/li>\n<li>Reubicabilidad: La unidad puede ser retirada y energizada en un nuevo sitio una vez que se traslada la carga.<\/li>\n<li>Espacio compacto: Unas pocas docenas de metros cuadrados son suficientes en lugar de enormes terrenos cercados y conectados.<\/li>\n<li>Log\u00edstica fluida: El \u00fanico paquete a entregar en comparaci\u00f3n con decenas de env\u00edos separados es una gran ventaja.<\/li>\n<\/ul>\n<p>En el caso de proyectos de generaci\u00f3n renovable distribuida, estas ventajas se multiplican ya que hay docenas de unidades id\u00e9nticas y esa es la raz\u00f3n por la cual las granjas solares y los proyectos de electrificaci\u00f3n rural tienden a utilizar subestaciones prefabricadas en lugar de estaciones construidas en el sitio.<\/p>\n<h2 id=\"compare\">Subestaci\u00f3n prefabricada vs. convencional<\/h2>\n<table>\n<thead>\n<tr>\n<th>Factor<\/th>\n<th>Transformador prefabricado<\/th>\n<th>Subestaci\u00f3n convencional<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Trabajos civiles<\/td>\n<td>Solo base de concreto<\/td>\n<td>Building, foundation, fencing<\/td>\n<\/tr>\n<tr>\n<td>Installation time<\/td>\n<td>2\u20135 days<\/td>\n<td>4\u201312 semanas<\/td>\n<\/tr>\n<tr>\n<td>Prueba<\/td>\n<td>Factory type-tested complete unit<\/td>\n<td>Site-assembled, partially untested<\/td>\n<\/tr>\n<tr>\n<td>Relocation<\/td>\n<td>Yes<\/td>\n<td>No<\/td>\n<\/tr>\n<tr>\n<td>Huella<\/td>\n<td>~10\u201340 m\u00b2<\/td>\n<td>Typically 100+ m\u00b2 with access<\/td>\n<\/tr>\n<tr>\n<td>Total installed cost<\/td>\n<td>20\u201340% lower typical<\/td>\n<td>Higher civil and labor share<\/td>\n<\/tr>\n<tr>\n<td>Customization<\/td>\n<td>Configurable but standardized<\/td>\n<td>Fully bespoke<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Traditional substations are the appropriate solution for transmission voltages of 66 kV and higher as well as huge distribution centers in stable buildings. For less than 40.5 kV, the prefabricated substation is now the norm in the majority of foreign markets.<\/p>\n<h2 id=\"specs\">Typical Specifications<\/h2>\n<p>A typical demonstrative medium-sized unit of 630 kVA, 33 kV\/0.4 kV, used in various industrial and commercial projects.<\/p>\n<table>\n<thead>\n<tr>\n<th>Par\u00e1metro<\/th>\n<th>Valor T\u00edpico<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Transformer rating<\/td>\n<td>630 kVA, oil-immersed, ONAN<\/td>\n<\/tr>\n<tr>\n<td>Voltaje primario<\/td>\n<td>33 kV (also 11\/22\/35 kV)<\/td>\n<\/tr>\n<tr>\n<td>Voltaje secundario<\/td>\n<td>400\/230 V, 50 Hz<\/td>\n<\/tr>\n<tr>\n<td>Grupo vectorial<\/td>\n<td>Dyn11<\/td>\n<\/tr>\n<tr>\n<td>P\u00e9rdida en vac\u00edo<\/td>\n<td>~1.0\u20131.3 kW (depends on loss class)<\/td>\n<\/tr>\n<tr>\n<td>Load loss at 75\u00b0C<\/td>\n<td>~7.5\u20139.5 kW<\/td>\n<\/tr>\n<tr>\n<td>Voltaje de impedancia<\/td>\n<td>4%\u20136%<\/td>\n<\/tr>\n<tr>\n<td>Interruptores de media tensi\u00f3n<\/td>\n<td>SF6 RMU, 630 A busbar, 20 kA\/3s<\/td>\n<\/tr>\n<tr>\n<td>LV switchboard<\/td>\n<td>400 A\u2013630 A main, MCCB outgoing feeders<\/td>\n<\/tr>\n<tr>\n<td>Recinto<\/td>\n<td>IP54, hot-dip galvanized base, painted steel<\/td>\n<\/tr>\n<tr>\n<td>Nivel de ruido<\/td>\n<td>\u2264 55 dB(A) at 1 m per IEC 60076-10<\/td>\n<\/tr>\n<tr>\n<td>Normas<\/td>\n<td>IEC 62271-202, IEC 60076, IEC 60529<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Standard tests carried out as per IEC 60076, include testing of resistance of windings, testing of ratio and group of windings, short-circuit impedance, testing of no-load and load losses including insulation resistance and dielectric tests for the specified value of voltage. Type tests comprise tests for temperature rise, tests for impulse voltage, and tests for short-circuit resistance.<\/p>\n<h2 id=\"applications\">Application Areas<\/h2>\n<ul>\n<li>In urban and commercial distribution, residences, malls, office buildings, and streets create an environment where space utilization and speed of energization are important.<\/li>\n<li>In the case of industrial areas, there is only one solution per factory or cluster. Units in this category can adapt their capacity in increments of 400-1,600 kVA depending on the growth of tenants.<\/li>\n<li>For renewable energy plants, prefabricated units serve as a connection point between inverter stations and the grid. The size of these units varies from 1,000 to 4,000 kVA.<\/li>\n<li>In terms of rural electrification, mini-prefabricated units allow connecting remote villages and farmers to the grid.<\/li>\n<li>For temporary and emergency power, an example would be the installation of skid-mounted units on disaster recovery, events, or construction sites quickly.<\/li>\n<li>Mining and remote operations installations rely on ready-made products for lack of local production capabilities.<\/li>\n<\/ul>\n<p>In all cases the unit has the same objectives: to take the medium-voltage feed, convert it to utilization voltage, protect it, meter it and deliver the necessary amount of power to a specific load.<\/p>\n<h2 id=\"standards\">Standards and Testing<\/h2>\n<table>\n<thead>\n<tr>\n<th>Est\u00e1ndar<\/th>\n<th>Alcance<\/th>\n<th>Key Buyer Check<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>IEC 62271-202<\/td>\n<td>Prefabricated transformer substations<\/td>\n<td>Complete-unit type tests: temperature rise, short circuit, dielectric<\/td>\n<\/tr>\n<tr>\n<td>IEC 60076<\/td>\n<td>Transformadores de potencia<\/td>\n<td>Rating, losses, routine and type tests<\/td>\n<\/tr>\n<tr>\n<td>IEC 60529<\/td>\n<td>Enclosure protection (IP code)<\/td>\n<td>IP54 minimum for outdoor units<\/td>\n<\/tr>\n<tr>\n<td>IEC 62271-200<\/td>\n<td>MV metal-enclosed switchgear<\/td>\n<td>RMU safety and internal arc classification<\/td>\n<\/tr>\n<tr>\n<td>IEC 61000-4<\/td>\n<td>EMC (electromagnetic compatibility)<\/td>\n<td>Relay immunity in the enclosure<\/td>\n<\/tr>\n<tr>\n<td>IEEE C57.12.27 (N. America)<\/td>\n<td>Pad-mount equipment integrity<\/td>\n<td>Dead-front construction, tamper resistance<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>In export orders, one of the most important documents is IEC 62271-202 type test report for the entire unit, especially temperature-rise test with fitted enclosure. Some suppliers with low costs carry out tests only for the transformer without its enclosure, which may conceal derating issues in hot climate areas. Always make sure that you request the report on the complete unit. In case of large orders, you might need a factory test witness as well.<\/p>\n<h2 id=\"costs\">Costs and Price Ranges<\/h2>\n<p>Indicative prices for prefabricated transformer stations (RMU switchgear, oil-transformer station, LV panel, conventional painted steel enclosure):<\/p>\n<table>\n<thead>\n<tr>\n<th>Clasificaci\u00f3n<\/th>\n<th>Voltage Class<\/th>\n<th>Precio t\u00edpico (USD)<\/th>\n<th>Lead Time<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>100\u2013315 kVA<\/td>\n<td>11\u201335 kV<\/td>\n<td>$4,000\u2013$12,000<\/td>\n<td>5\u201310 weeks<\/td>\n<\/tr>\n<tr>\n<td>400\u2013630 kVA<\/td>\n<td>11\u201335 kV<\/td>\n<td>$7,000\u2013$20,000<\/td>\n<td>6\u201312 weeks<\/td>\n<\/tr>\n<tr>\n<td>800\u20131,250 kVA<\/td>\n<td>11\u201335 kV<\/td>\n<td>$11,000\u2013$33,000<\/td>\n<td>8\u201314 weeks<\/td>\n<\/tr>\n<tr>\n<td>1,600\u20132,500 kVA<\/td>\n<td>11\u201335 kV<\/td>\n<td>$24,000\u2013$60,000<\/td>\n<td>10\u201318 weeks<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>One can add 15-30% for stainless-steel enclosures and 10-20% for dry transformers. In addition you would add $800-3000 for metering, monitoring, SCADA options. Prices are indicative FOB basis and may differ according to specification and brand. For losses evaluation purposes the 630 kVA unit with 500-1000 W lower no-load loss can save $300-900 in running costs, what might be important taking into account the asset lifetime of 25 years.<\/p>\n<h2 id=\"brands\">Top Brands &amp; Price Comparison<\/h2>\n<table>\n<thead>\n<tr>\n<th>Marca<\/th>\n<th>Pa\u00eds<\/th>\n<th>Fuerza<\/th>\n<th>Indicative Price \u2014 1,000 kVA (USD)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Schneider Electric<\/td>\n<td>Francia<\/td>\n<td>RMU integration, global compact substation range<\/td>\n<td>$22,000\u2013$38,000<\/td>\n<\/tr>\n<tr>\n<td>Siemens<\/td>\n<td>Alemania<\/td>\n<td>Digital substation options, integrated protection<\/td>\n<td>$23,000\u2013$40,000<\/td>\n<\/tr>\n<tr>\n<td>ABB<\/td>\n<td>Suiza<\/td>\n<td>Broad portfolio, strong utility references<\/td>\n<td>$22,000\u2013$39,000<\/td>\n<\/tr>\n<tr>\n<td>Eaton<\/td>\n<td>EE. UU.<\/td>\n<td>Pad-mount strength, North American market<\/td>\n<td>$20,000\u2013$36,000<\/td>\n<\/tr>\n<tr>\n<td>Hyosung \/ LS Electric<\/td>\n<td>Korea<\/td>\n<td>Compact units, strong Southeast Asia presence<\/td>\n<td>$19,000\u2013$34,000<\/td>\n<\/tr>\n<tr>\n<td>Jiangsu Subian Electric Power<\/td>\n<td>China<\/td>\n<td>IEC 62271-202 units, oil\/dry options, OEM<\/td>\n<td>$11,000\u2013$33,000<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The main players on the market offer brand reliability, matured RMU product lines and global service network, which is of utmost importance for large utilities bidding with rigid insurance requirements. Jiangsu Subian Electric Power operates in a price-sensitive market segment offering IEC 62271-202-compliant prefabricated transformer substations with both oil-immersed and dry transformers, RMU or breaker switchgear and painted or stainless or composite enclosure.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-10838\" src=\"https:\/\/subian-electric.com\/wp-content\/uploads\/2026\/08\/How-to-Choose-and-Buy.webp\" alt=\"How to Choose and Buy\" width=\"1448\" height=\"1086\" \/><\/p>\n<h2 id=\"howtochoose\">How to Choose and Buy<\/h2>\n<ul>\n<li>Determine the necessary load in kVA, as well as growth plan and power factor; make sure that maximum load does not exceed 60-80% of transformer rating.<\/li>\n<li>Establish network voltage and configuration (loop, radial, dual-feed), which will help to determine if to use RMU or circuit breaker.<\/li>\n<li>Match transformer to the site condition: oil-insulated transformer for open sites and dry transformer for indoor sensitive areas.<\/li>\n<li>Select the enclosure material depending on the environment: painted steel for good conditions, while stainless steel or composite is preferred in corrosive locations.<\/li>\n<li>Request full unit testing per IEC 62271-202 standards instead of merely transformer tests.<\/li>\n<li>Evaluate tropical deration; require temperature raise testing report for the ambient temperature over 40 C.<\/li>\n<li>Make comparisons based on losses not the price and add remote monitoring system in case the site is not manned.<\/li>\n<li>Verify the lead time and transportation; 630 kVA transformer unit fits into 40 ft container with larger units needing open top or flat rack transportation.<\/li>\n<\/ul>\n<h2 id=\"faq\">Preguntas Frecuentes<\/h2>\n<h3>What is the difference between a prefabricated transformer and a box-type substation?<\/h3>\n<p>Both prefabricated transformer and box-type substation refer to the same type of equipment which represents an MV\/LV distribution device with a transformer, switchgear, and LV panel factory assembled in one enclosure according to IEC 62271-202. The term box type is widely used in China and in some regions of Asia whereas the term prefabricated substation is included in the IEC nomenclature and is commonly used in Europe and export tenders.<\/p>\n<h3>How much does a prefabricated transformer cost?<\/h3>\n<p>In general, the whole 400-1,000 kVA prefabricated transformers cost between $7,000 and $33,000 according to the switchgear types, enclosure materials, and loss classes while the prices of the 1,600-2,500 kVA ones start from $24,000 and can reach $60,000. If the enclosure is made of stainless steel, the cost increases by 15-30%, dry-type transformers add 10-20%, and monitoring upgrades do the same by $800-$3,000. The cost of shipping and installation is not included and should be considered separately.<\/p>\n<h3>How long does installation take?<\/h3>\n<p>The installation process generally lasts from 2 to 5 days if a concrete pad is ready beforehand and includes the work of cranes, fastening the unit, connecting the cables, etc. In comparison, the installation of a conventional substation takes from 4 to 12 weeks. As the unit is tested in the factory, commissioning problems arise rarely if the cable and pad correspond to the structure&#8217;s drawing.<\/p>\n<h3>Can a prefabricated transformer be relocated or upgraded later?<\/h3>\n<p>Yes, it is possible to lift and transport the unit to a new place; it is also possible to change the transformer for a bigger one having the same design. This is of great value for different industrial parks or temporary power connections and it is necessary for changing urban load situation.<\/p>\n<h3>What tests should I require before accepting a unit?<\/h3>\n<p>Before accepting a unit, it is necessary to require tests for the transformer according to IEC 60076 (calibration, winding resistance, losses, dielectric strength), tests for the switchgear and complete test for the whole prefabricated unit according to IEC 62271-202 (temperature rise with the enclosure, short-circuit resistance and internal arc). If it is an export unit, the tests should be witnessed by a representative of the receiving side and a certificate should be provided for shipment.<\/p>\n<h2 id=\"references\">Referencias<\/h2>\n<ul>\n<li><a href=\"https:\/\/webstore.iec.ch\" rel=\"nofollow noopener\" target=\"_blank\">IEC 62271-202 \u2014 High-voltage switchgear and controlgear: Prefabricated substations<\/a> \u2014 the governing standard for prefabricated transformer design, safety, and complete-unit type testing.<\/li>\n<li><a href=\"https:\/\/iec.ch\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60076 series \u2014 Power transformers<\/a> \u2014 the base standard for ratings, losses, and testing of the transformers inside the unit.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\" rel=\"nofollow noopener\" target=\"_blank\">IEC 62271-200 \u2014 MV metal-enclosed switchgear<\/a> \u2014 requirements for RMU and breaker compartments.<\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60529 \u2014 Degrees of protection (IP Code)<\/a> \u2014 defines IP54\/IP55 enclosure ratings for outdoor units.<\/li>\n<li><a href=\"https:\/\/standards.ieee.org\" rel=\"nofollow noopener\" target=\"_blank\">IEEE C57.12.27 \u2014 Pad-mounted equipment enclosure integrity<\/a> \u2014 North American dead-front and tamper-resistance requirements.<\/li>\n<li><a href=\"https:\/\/www.nema.org\" rel=\"nofollow noopener\" target=\"_blank\">NEMA \u2014 Distribution transformer application guidance<\/a> \u2014 rating and application guidance for transformer equipment in the Americas.<\/li>\n<li><a href=\"https:\/\/subian-electric.com\/es\/\" rel=\"nofollow\">Jiangsu Subian Electric Power \u2014 official site<\/a> \u2014 manufacturer and exporter of IEC 62271-202 prefabricated transformer substations.<\/li>\n<\/ul>\n<h2 id=\"conclusion\">Conclusi\u00f3n<\/h2>\n<p>Transformers prefabricated have become important tools of modern-day electric distribution, since it allows providing speediness, controlling costs, having factory quality, and giving flexibility in one transportable package. A full-fledged substation; which includes transformer, MV switchgear, LV switchgear, metering, and protection; arrives tested, and makes installation in days, rather than months.<\/p>\n<p>Main points:<\/p>\n<ul>\n<li>Specify on the peak load at 60-80% of the transformer rate and select switchgear according to network configuration.<\/li>\n<li>Choose the material of covering according to the setting and select stainless or composite for coastal or aggressive environments.<\/li>\n<li>Request IEC 62271-202 complete-unit type tests instead of just transformer tests.<\/li>\n<li>Evaluate offers according to losses and understand container logistics and lead time.<\/li>\n<li>Integrate global brands like Schneider, Siemens or ABB together with IEC-certified suppliers like Jiangsu Subian Electric Power.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>It is Tuesday morning at a medium-sized industrial estate near Nairobi, and the electricity crew has only one week to connect a new shoe production plant that was connected eight days ago. No one on the construction site is making a transformer platform or waiting for a brick enclosure; instead, a crane is lifting a [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":10836,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[77],"tags":[],"class_list":["post-10835","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/posts\/10835","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/comments?post=10835"}],"version-history":[{"count":2,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/posts\/10835\/revisions"}],"predecessor-version":[{"id":11001,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/posts\/10835\/revisions\/11001"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/media\/10836"}],"wp:attachment":[{"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/media?parent=10835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/categories?post=10835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/subian-electric.com\/es\/wp-json\/wp\/v2\/tags?post=10835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}