Technology Literature

Common faults of 66kV power transformers

66kV power transformer, as the hardware equipment of the power supply system, plays an important role in regulating the power consumption and maintaining the normal operation of the power supply system in the whole system. This paper briefly analyzes and discusses the importance of safe operation of 66kV power transformers and specific protective measures based on the reasons for the failure of power transformers and their operation status.

1 The importance of safe use of 66kV power transformers

1.1 Operational status of 66kV power transformers
As one of the most commonly used standard power equipment, the 66kV power transformer plays an extremely important role in the power supply that meets the daily needs of society. However, with the continuous development of social economy, the demand for electric power is also increasing day by day, and higher requirements are put forward for the use efficiency of voltage devices. Now, due to the insufficient technological development of transformers, the frequency of 66kV power transformer accidents is increased.

1.2 Specific reasons for the failure of 66kV power transformers
Electricity safety is one of the basic conditions for electric power operation. For the problems that may occur during the operation of 66kV power transformers, the fault conditions can be roughly divided into two types.

The first is that the hardware equipment of the transformer is damaged, so that the normal operation of the power facility cannot be maintained, for example, the coil of the transformer is deformed. Therefore, in order to reduce the frequency of power accidents, the hardware maintenance and repair of the transformer should be carried out on a regular basis to ensure that the equipment maintains a good operating condition;

The second is the serious burning loss inside the transformer due to the excessively regulated voltage. Since the circuit is overheated due to internal reasons, in order to prevent this from happening, voltage shunting and limiting should be implemented. For example, formulate relevant systems and regulations to reduce the pressure on transformers during peak periods of power consumption; or install power shunt equipment in high accident frequency bands to improve the efficiency of transformers and minimize the possibility of power accidents, so as to achieve safe power consumption. Power target.

2 66kV power transformer fault analysis

2.1 Coil deformation failure.
For example, during the operation of a 66kV transformer, there was an abnormal chromatographic phenomenon, and its absolute gas production rate and total hydrocarbons exceeded the normal values, and were higher than the values that need attention. Therefore, we judge it as a low temperature overheating failure of high energy, solid insulation carbonization.

 2.2 Fault caused by short circuit outside the zone
Through the disassembly analysis of the transformer, the low-voltage, high-voltage and voltage regulating coils do not use cardboard tubes; it does not have a lower pressure plate, and the upper pressure plate is made of laminated wood, and the voltage regulating coil has no external locking stays; its The insulating coil is formed by bonding ordinary cardboard, which does not have sufficient mechanical strength. The press-fit structure is not in compliance with the specification, the press points are missing, and the support plate is not filled. Through calculation, the current that caused the short circuit this time is about 9400A, which is more than 5 times the specified current limit. Under the strong impact of this short-circuit current, the transformer has the phenomenon of coil deformation, and then the inter-turn insulation breakdown.

3. 66kV power transformer fault prevention measures

3.1 Focus on prevention and focus on the investigation of potential safety hazards
For the failure of power transformers, prevention should be the main focus, detailed inspection and maintenance should be carried out to eliminate hidden dangers from the source, and prevention should be the main starting point for solving problems. Organize a special power equipment inspection team to maintain and manage basic equipment such as transformers and ensure the normal operation of circuit equipment. The most common cause of failure in 66kV transformers is the short circuit of the line due to excessive operating pressure. Compared with the 10kV line, the 66kV transformer needs to withstand a larger voltage in order to ensure the normal operation of the power system. Due to the excessive power, short circuits often occur.


66kV power transformer, as one of the most widely used basic substation equipment in transformers, plays a very important role in maintaining normal power consumption of residents, alleviating power consumption pressure, and promoting the safe and stable development of power. In order to reduce the frequency of power failures and ensure power supply In order to ensure the safety and stability of the system operation, relevant departments should strengthen the investigation of potential safety hazards of power equipment, ensure that the hardware equipment of the power supply system meets the use standards, and formulate detailed and strict rules and regulations to ensure the professional level of the regular inspection team, so as to realize the realization of the power industry. rapid and healthy development, and promote the development process of modern society.