ESTUDIO TÉCNICO ECONÓMICO PARA LA IMPLEMENTACIÓN DEL MÉTIDO VPI, APLICADO A LA FABRICACIÓN DE TRANSFORMADORES SECOS EN SCHAFFNER S.A.

Abstract

Schaner S.A. It is in process of OHSAS 18001 certi cation; and evaluated the possibility to manufacture dry transformers up to 15kV class. The current process for applying varnish to the coils used in the factory has many limitations to comply with these two objectives of the company. The current method is immersion, which consists in immersing the part of these transformers in a steel tank with varnish. This method does not achieve levels dielectric, thermal, mechanical adequate to produce transformers up to 15kV class. Currently transformers are manufactured to 8,7kV class, which considerably reduces the range of dry type transformers built and oered by Schaner and must purchase dry transformers in the international market and contract laboratory services so as to meet the standards and requirements. That is why it is essential to investigate and implement an impregnation process to improve the quality of insulation and allow to increase the voltage class of dry transformers, in addition to a safe, automatic and hermetic process. The VPI is a system method for applying varnish or resin impregnation technique using vacuum and pressure, and introduces the advantage to penetrate all areas of the coil and core compared to traditional methods. The varnish or resin permeates the entire machine protecting the external environment, strengthening the insulation between coils and insulation between core and coils, linking all parts of the machine vibration and noise reducing transformer. Internally eliminates the air spaces in coils, thereby improving the heat exchange from the inside of the coil due to the better thermal conductivity of varnishes and resins, and most importantly reduces the existence of vacuoles, which avoids concentrations electric eld withstanding higher voltage levels and greater protection to overvoltages. A variety of resins and varnishes for use VPI, the resin must be selected that meets the technical requirements of dry transformers, which are economical, with low costs during the process as well as its maintenance. It should be taken into account the origin of the goods and if their production meets environmental regulations. The VPI system manufactures and markets on demand in dierent parts of the world. On-site Schaner SA, there is a company of the group, called Hidropack that manufactures and builds uid control systems, ponds damping water hammer, etc. There are all technical conditions necessary to build the VPI system. The objective of this report is to gather information on the resin impregnation and vacuum pressure applied to dry transformers, resins and varnishes available, then set the criteria of quality of the nished product and the evidence necessary to analyze and evaluate the approval of degree impregnation and nally evaluate the technical and economic VPI project, selecting the most suitable and convenient alternative for implementation in Schaner.Schaner S.A. esta en proceso de certi cacion de OSHAS 18001; y se evalua la posibilidad de fabricar transformadores secos hasta clase 15kV. El proceso actual para aplicar barniz a las bobinas utilizado en la fabrica tiene bastantes limitaciones para poder dar cumplimiento a estos dos objetivos de la empresa. El metodo actual utilizado es por inmersion, que consiste en sumergir los transformadores o parte de ellos en un tanque de acero con barniz. Este metodo no permite lograr niveles dielectricos, termicos, ni mecanicos adecuados para fabricar transformadores hasta clase 15kV. Actualmente se fabrican transformadores hasta clase 8,7kV, lo que reduce considerablemente la gama de transformadores secos construidos y ofrecidos por Schaner, debiendo recurrir en la compra de transformadores secos en el mercado internacional y contratar servicios de laboratorio de manera de poder cumplir las normas y requerimientos para participar y ofertar en los distintos proyectos y licitaciones del mercado nacional. Es por esto que se hace imprescindible investigar e implementar un proceso de impregnacion que mejore la calidad del aislamiento y permita aumentar la clase de tension de los transformadores secos fabricados, ademas de contar con un proceso seguro, automatico y hermetico. El metodo VPI es un sistema de aplicacion de barniz o resina que utiliza la tecnica de impregnacion por vaco y presion, y que introduce la ventaja de penetrar en todas las areas de la bobina y nucleo en comparacion con los metodos tradicionales. La implementacion de este metodo en Schaner permitira construir y comercializar transformadores hasta clase 15kV, aumentando la calidad del producto, aumentando la clase de tension de los transformadores secos ofrecidos y aumentando las utilidades de los transformadores secos Schaner