The protection of transformer mainly includes overload protection, short circuit protection, overvoltage protection and undervoltage protection. These protective measures are of great significance to ensure the normal operation of the transformer and prolong its service life.
Overload protection is the most common type of transformer protection. When the transformer is subjected to a load that exceeds its rated capacity, the overload protection device is activated to prevent damage to the transformer due to overload, for example, by limiting the current or reducing the voltage. Overload protection devices typically include thermal relays, overload trippers, etc.
Short-circuit protection is set to prevent the transformer from being damaged in the event of a short-circuit fault. When the short circuit occurs, the current will increase by tens or even hundreds of times instantaneously, causing a great impact on the transformer. As a result, the short-circuit protection device is able to quickly cut off the power supply in the event of a short circuit, thus protecting the transformer from damage. Short-circuit protection is usually achieved through devices such as current transformers, short-circuit trippers, etc.
Overvoltage protection is set to prevent damage to the transformer when the voltage is too high. When the grid voltage is too high, the insulation of the transformer may be damaged, resulting in damage to the transformer. Overvoltage protection protects the transformer from damage by automatically cutting off the power supply or lowering the voltage when the voltage is too high. Overvoltage protection is usually achieved by lightning arresters, voltage transformers and other equipment.
Under-voltage protection is set to prevent the transformer from working properly when the voltage is too low. When the grid voltage is too low, the output voltage of the transformer will also decrease accordingly, and it may not be able to meet the normal demand of the electrical equipment. When the voltage is too low, the under-voltage protection device can automatically cut off the power supply or send an alarm signal to remind the user to take measures to restore the voltage to normal. Under-voltage protection is usually achieved through equipment such as voltage transformers and under-voltage trippers.
In addition to the above four basic protections, there are some other protections that can be used to protect transformers. For example, temperature protection can monitor the temperature of the transformer in real time by installing a temperature sensor on the transformer, and issue an alarm or cut off the power supply when the temperature is too high;Gas protection is by installing a gas relay inside the transformer tank, when the transformer is faulty and produces gas, the gas relay will act to cut off the power supply, so as to protect the transformer from damage.
In practical application, the protection measures of transformers need to be comprehensively considered according to the type, capacity, operating environment and other factors of the transformer. At the same time, the selection, installation, commissioning and maintenance of the protection device are also very important, and they need to be operated by professional technicians.
In addition, with the continuous development of the power system, the protection measures of transformers are also constantly upgraded and improved. For example, the intelligent protection devices that have emerged in recent years can achieve more accurate and fast protection actions and improve the stability and reliability of the power system. At the same time, with the access of new energy and distributed power sources, the protection of transformers also needs to consider more complex and changeable operating conditions.
In short, transformer protection is one of the important measures to ensure the stable operation of the power system and the reliability of power supply. In practical application, it is necessary to comprehensively consider various factors, take appropriate protection measures, and strengthen the maintenance and management of protection devices to ensure the safe and stable operation of transformers.