Transformer Accessories
Transformer accessories enhance the system's functionality, its protection, and its reliability. They are necessary because protecting people and property necessitates precautions all along the line and at every point through which electricity flows.
Detecting abnormal events of the power system is the basic mission of protective relays. Some of the most important abnormal incidents that protective relays detect are overcurrents, overvoltages, and short circuits. As soon as these protective relays sense that one of these incidents has occurred, they take immediate action to reduce the possibility of system damage. For instance, if a protective relay detects an overvoltage incident, it can immediately cause a circuit breaker to open, thus disconnecting the overvolted system component from the rest of the system.
Insulating devices (called bushings) allow electric currents to safely pass through the tank that contains a transformer. Bushings are designed to maintain electric isolation between the inside and outside of a transformer. Since by definition a transformer bushing must withstand voltage and carry electric current, its operational reliability is vital to safe and efficient transformer performance.
Transformers take one type of voltage and convert it to a different kind of voltage. The amount of energy being used stays the same. When voltage is increased or decreased by a transformer, the amount of energy is not increasing or decreasing, it is simply changing the way the energy is being used. Ohms law (V=IR) shows that the current will change proportionally to the voltage. Therefore when voltage increases, amperage decreases. When voltage decreases, amperage increases. A transformer can take any type of AC voltage and change that voltage either up or down. For example, power companies use transformers to change the voltage from a very high, dangerous voltage down to a level that can be safely used in homes. In industrial applications, transformers step down voltage from 480VAC to 120VAC to use in control circuits.