Transformer overload protection is one of the most important parts of an electrical system. It keeps a transformer from being damaged or destroyed by excessive currents or voltages. When a transformer is overloaded, it draws too much current and the voltage drops to unsafe levels. This can lead to overheating, arcing, and even fire. In order to prevent such damage, transformers use a variety of overload protection devices.
The most common device is a temperature-responsive overload relay. This device monitors the temperature of the windings inside the transformer and shuts off the power supply if it detects an excessive temperature rise in the windings. This helps protect the transformer from winding destruction and can prevent a fire from breaking out.
Another protective device is a differential current transformer (DCT). This type of transformer monitors the current within the windings of the transformer and shuts off the power supply when a certain level is exceeded. This prevents excessive currents from damaging the windings and equipment.
In addition to these devices, some transformers are equipped with current transformers (CTs). These devices continuously monitor the current within the windings and shut off the power supply if a predetermined current level is exceeded. This helps to ensure that the current levels stay within the safe range.
Finally, a harmonic monitoring relay can be used in combination with a temperature- or current-based overload relay to provide additional protection against transformer overloads. This device monitors the harmonic distortion within the transformer’s output current and shut off the power supply if certain harmonics exceed a predetermined threshold.
All these protective devices are essential for safe and reliable transformer operation. Properly configured, they can protect the transformer from excessive currents or voltages and keep the transformer from being damaged or destroyed by an overload.
