Function of power transformer

Power transformers are one of the main pieces of equipment in power plants and substations. Transformers serve multiple functions: they not only raise voltage to deliver electrical energy to the user area, but also lower voltage to meet various usage levels. In short, both voltage step-up and step-down must be accomplished by transformers. During the transmission of electrical energy in a power system, both voltage and power losses inevitably occur. When transmitting the same power, voltage loss is inversely proportional to the voltage, and power loss is inversely proportional to the square of the voltage. Using transformers to raise voltage reduces transmission losses.

A transformer consists of two or more coil windings wound on the same iron core. The windings are connected by an alternating magnetic field and operate according to the principle of electromagnetic induction. The installation location of the transformer should consider ease of operation, maintenance, and transportation, and should be chosen in a safe and reliable location. When using a transformer, its rated capacity must be selected appropriately. When a transformer is running under no-load, it requires a large amount of reactive power. This reactive power must be supplied by the power supply system. Choosing a transformer with an excessively large capacity not only increases initial investment but also forces the transformer to operate under no-load or light-load conditions for extended periods. This increases the proportion of no-load losses, lowers the power factor, and increases network losses, making the operation neither economical nor efficient. Conversely, choosing a transformer with an excessively small capacity will cause it to be overloaded for extended periods, potentially damaging the equipment. Therefore, the rated capacity of the transformer should be selected based on the required electrical load and should not be too large or too small.