Optimal sizing of solar energy transformers using natural ester fluid

As a result of the increasing number of nation-states that are adopting aggressive Renewable & Alternative Energy Portfolios, the solar energy market is nearly doubling year over year. With this aggressive growth comes even greater scrutiny when sizing solar farms. There is often great incentive to get the most utilization out of the equipment. An often over looked piece of equipment on these farms is the liquid filled AC padmount transformer. Given the green nature of the solar market, every Cooper Power Systems Envirotran™ Solar transformer contains the non-toxic, biodegradable Envirotemp™ FR3™ fluid, made from renewable seed oils. Equal in importance to its biodegradability, this natural ester fluid substantially extends the life of the cellulosic insulation in the transformer, while allowing periods of overloading of the transformer. The high fire point of natural ester fluid provides a safer transformer for solar applications compared to mineral oil, especially during periods of high ambient temperature and unit overloading. This work presents how using the inherent properties of natural ester fluid in conjunction with defined inverter load profile and site environmental conditions can help optimize transformers for Solar PV applications.