A brief introduction to the protection configuration of factory dry-type transformers
Protection configuration of factory low-voltage transformers. Generally speaking, the protection configuration can be determined according to the actual application scenarios and requirements, and the following are some common protection configurations.
In the low-voltage transformers used in the factory, dry-type transformers are used, and their protection configurations are the same, all of which are equipped with current quick break protection, overcurrent protection, grounding protection, and over-temperature protection. Zero-sequence overcurrent protection.
Protection function of factory low-voltage transformer.
Current quick break protection: mainly protects the transformer.
When a symmetrical or asymmetrical interphase short circuit fault occurs in the primary and secondary winding circuits, it acts in tripping, effectively removes the expansion and spread of the fault, reduces the degree of damage to the transformer, and is the main protection of the transformer. This protection is usually implemented by devices such as circuit breakers or fuses. The power supply can be quickly cut off to avoid damage to the transformer.
Overcurrent protection, mainly to protect the transformer when the external circuit of the transformer is overcurrent or short-circuit fault, the current exceeds the predetermined threshold, the protection device will automatically start, act on tripping, effectively prevent external faults from causing damage to the transformer, and prevent the transformer from overheating. It is a backup protection for the main protection of the transformer.
This protection detects the magnitude of the current in the transformer by means of a current transformer installed inside or outside the transformer and converts it into an electrical signal to send to the protection device. Based on the current signal, the protection device determines whether a predetermined threshold has been exceeded, and if so, issues a command to cut off the power to the transformer to protect the transformer from overheating.
Grounding protection: It mainly protects the transformer from tripping when a single-phase grounding fault occurs in the circuit of 6,000 volts and above, which effectively prevents damage to the primary winding of the transformer and protects the primary winding of the transformer. This protection is typically implemented by devices such as grounding relays or zero-sequence current transformers. The power supply can be quickly cut off to avoid damage to transformers and other equipment.
Zero sequence overcurrent: Zero sequence overcurrent protection is a device to protect the transformer, which is mainly used to protect the 0 of the transformer4 thousand volt circuit. When a single-phase grounding fault occurs, the zero-sequence overcurrent protection will act on tripping, which effectively prevents damage to the secondary winding of the transformer and improves the operation reliability and safety of the transformer. It is the protection of the secondary winding of the transformer. The secondary winding refers to the winding of the low-voltage side of the transformer, when a single-phase grounding fault occurs in the circuit, the fault current will pass through the secondary winding of the transformer, and the current will act quickly when the current exceeds the set value, cut off the fault current, and protect the safety of the transformer.
Over-temperature protection: It mainly protects the transformer to operate at the allowable temperature, and when the transformer temperature is too high and exceeds the allowable value, it will trip and send an alarm signal to remind the staff to take measures. It can effectively prevent the transformer from overheating and cause damage, which is the temperature protection of the transformer. Temperature protection is typically implemented by devices such as temperature sensors and control circuits. When the temperature of the transformer exceeds its maximum allowable temperature, the protection device is able to automatically cut off the power supply to avoid damage to the transformer from overheating.