The backup protection for transformer short-circuit faults mainly includes fuses, circuit breakers and differential protection devices.
1. Fuse: A fuse is a safety device used to protect a circuit. When the current exceeds the rated current value of the fuse, the fuse inside the fuse will blow, thereby disconnecting the circuit. When a short-circuit fault occurs in the transformer, the fuse can quickly cut off the circuit and protect the transformer.
2. Circuit breaker: A circuit breaker is an electrical switching device that combines switching and protection functions. In the event of a short-circuit fault in the transformer, the circuit breaker can quickly cut off the circuit, thereby preventing damage caused by excessive current. Typically, circuit breakers have overload protection and short circuit protection.
3. Differential protection device: The differential protection device is a device commonly used in transformer protection. It judges whether a short-circuit fault occurs based on the difference between the input and output currents of the transformer. When the differential current exceeds the set value, the differential protection device will quickly cut off the circuit to protect the transformer.
Under normal circumstances, these backup protection devices are equipped in the control cabinet of the transformer and connected to the winding of the transformer. By monitoring parameters such as current and voltage, it is judged whether a short-circuit fault occurs, so that protective measures can be taken at the first time to protect the safe operation of the transformer.