Introduction to the principle of transformer protection What is transformer charging protection? What are the protections for transformers?

1. Introduction to the principle of transformer protection

Transformers are commonly used electrical equipment in power systems. They are used to transform high voltage into low voltage, or transform low voltage into high voltage. During operation, the transformer may encounter various unexpected faults and fault protection requirements. At this time, correct protection principles and methods are particularly important.

The most fundamental principle of transformer fault protection is to protect the electrical insulation of the transformer. Failures in the transformer windings and oil will cause local heating of the transformer windings and insulating oil, produce gas and sediment, and may Causing fires and explosions. Therefore, the goal of the transformer protection system is to shut down the transformer in time and protect the safety of the equipment when a transformer fails.

2. What is transformer charging protection?

Transformer charging protection means that when the transformer is put into operation, due to the winding capacitance and the parasitic capacitance of the transformer itself, LC resonant circuits will be formed at the power supply end and the load end respectively. When the transformer cuts off the power supply, these capacitors will form a discharge current and generate a peak current, which will cause damage to the insulating oil, windings and winding supports. Therefore, it is necessary to provide charging protection for the transformer to prevent unnecessary failures of the transformer.

The principle of transformer charging protection is to install a wave arrester on the high voltage side of the transformer and use the wave arrester to limit the discharge current. When the transformer cuts off the power supply, the wave arrester will weaken the discharge current waveform. The function of the peak value can avoid excessive voltage and current on the transformer winding, thus ensuring the safe operation of the transformer.

3. What are the protections for transformers?

1. Overload protection

When the load current of the transformer exceeds the rated value, the temperature of the transformer winding will rise, exceeding the insulation temperature limit, causing equipment damage, and even Causing danger. Therefore, the overload protection of the transformer must be considered in the design and operation. During the protection process, the winding temperature of the transformer needs to be checked regularly to identify overload faults and take corresponding protective measures to prevent faults.

2. Short-circuit protection

When a short-circuit fault occurs in the transformer, the current in the transformer increases sharply, exceeding the transformer's design capacity, which can easily lead to winding and insulation damage or Damage other equipment surrounding the device. In order to ensure the safety of certain equipment (such as transformers), some automatic protection devices need to be installed. Short circuit protection can be divided into overcurrent protection, differential protection and grounding protection.

3. Under-voltage protection

When the transformer loses power or the power supply voltage drops to a certain level, the transformer will not be able to operate normally, which may lead to equipment failure. Undervoltage protection is a protection device designed for this situation. It is mainly implemented by detecting the voltage drop of the transformer. Once undervoltage is detected, the equipment can be automatically disconnected to avoid damage to the equipment.

4. Overvoltage protection

In some cases, due to sudden misoperation of the power supply or other reasons, the transformer will be subject to excessive voltage, that is, overvoltage. This It is necessary to prevent this situation through some protection systems. The principle of overvoltage protection is that an overvoltage protection device is installed at the high-voltage end of the transformer. When overvoltage is detected, the overvoltage protection device will cut off the power supply in real time, thereby protecting the transformer from being damaged by excessive voltage.

In general, transformers are a very important type of equipment in the power system. The protection related to them must ensure their safe and reliable operation. At the same time, various preventive and protective measures also need to be implemented in a timely manner. .