Measuring transformer: a key step to ensure safe and stable operation of power systems
Release Time : 2025-05-07
In modern power systems, measuring transformers, as one of the core components, bear the important responsibilities of voltage conversion and electrical isolation. In order to ensure that the transformer can work long-term and stably, it is particularly important to measure it accurately. Through scientific and reasonable testing methods, potential problems can be discovered in time, faults can be prevented, and equipment performance can be optimized, thereby ensuring the safe and reliable operation of the entire power system.
First of all, measuring the insulation resistance of measuring transformers is one of the basic means to assess its health. This test is mainly used to detect whether the insulation state of the winding to the ground or between the windings is good. In actual operation, a megohmmeter is usually used to apply a DC voltage and measure the current flowing through, and then calculate the insulation resistance value. A healthy transformer should have a high insulation resistance, which means that it can effectively prevent the occurrence of leakage. On the contrary, if the measured resistance value is lower than the standard range, it may indicate problems such as insulation aging and moisture, which require further inspection and treatment.
Secondly, the ratio measurement is also an important part of transformer testing. The so-called ratio, that is, the proportional relationship between the voltage of the primary coil and the secondary coil, reflects the expected voltage conversion capability of the transformer when it is designed. Accurate ratio measurement can not only verify whether the design parameters of the transformer meet the requirements, but also help identify whether there are faults such as short circuits or open circuits between the windings. Generally, a special ratio tester is used for measurement, which can automatically apply appropriate excitation signals and record response data, and then calculate the actual ratio value based on this information and compare and analyze it with the theoretical value.
In addition, the measurement of no-load loss and load loss should not be ignored. The former refers to the energy consumed by the magnetization of the core when the transformer is in a no-load state (that is, there is no load on the secondary side); the latter refers to the total energy loss including copper loss in addition to the above-mentioned iron loss under rated load conditions. Through the accurate measurement of these two losses, the energy conversion efficiency and thermal management of the transformer can be fully understood. For example, abnormally high no-load loss may be due to poor quality of the core material or manufacturing process defects; while excessive load loss may indicate problems such as excessive winding resistance or unreasonable heat dissipation design.
It is worth noting that partial discharge measurement is also a key technology in measuring transformer maintenance. Partial discharge refers to the phenomenon of incomplete breakdown inside or on the surface of the insulating medium under the action of an electric field. Although the intensity of this discharge is small, if it exists for a long time, it will gradually erode the insulating material and eventually lead to insulation failure. Therefore, regular partial discharge testing can help to warn of potential risks in advance and take corresponding measures to prevent them. At present, commonly used detection methods include ultrasonic detection method, pulse current method, etc., each of which has its own characteristics and is suitable for the needs of different occasions.
Finally, the temperature rise test is crucial to evaluate the safety and stability of the transformer. The transformer will generate a certain amount of heat during operation. If the heat dissipation is poor, the internal temperature will be too high, affecting the life of the equipment and even causing a fire accident. The temperature rise test is designed to simulate the actual working conditions and monitor the temperature rise of each part of the transformer to confirm whether it meets the temperature rise limit specified in the relevant standards. This not only tests the cooling system design of the transformer itself, but also indirectly reflects the rationality of the overall structural layout.
In summary, measuring transformer covers many aspects from basic insulation performance to complex energy loss. Each test is directly related to whether the equipment can operate normally and its service life. By implementing a comprehensive and detailed measurement plan, not only can the reliability of the power system be improved and unexpected downtime be reduced, but it can also help reduce operation and maintenance costs and maximize economic benefits. Therefore, both manufacturers and users should attach importance to various transformer measurements to ensure the continuity and safety of power supply.
First of all, measuring the insulation resistance of measuring transformers is one of the basic means to assess its health. This test is mainly used to detect whether the insulation state of the winding to the ground or between the windings is good. In actual operation, a megohmmeter is usually used to apply a DC voltage and measure the current flowing through, and then calculate the insulation resistance value. A healthy transformer should have a high insulation resistance, which means that it can effectively prevent the occurrence of leakage. On the contrary, if the measured resistance value is lower than the standard range, it may indicate problems such as insulation aging and moisture, which require further inspection and treatment.
Secondly, the ratio measurement is also an important part of transformer testing. The so-called ratio, that is, the proportional relationship between the voltage of the primary coil and the secondary coil, reflects the expected voltage conversion capability of the transformer when it is designed. Accurate ratio measurement can not only verify whether the design parameters of the transformer meet the requirements, but also help identify whether there are faults such as short circuits or open circuits between the windings. Generally, a special ratio tester is used for measurement, which can automatically apply appropriate excitation signals and record response data, and then calculate the actual ratio value based on this information and compare and analyze it with the theoretical value.
In addition, the measurement of no-load loss and load loss should not be ignored. The former refers to the energy consumed by the magnetization of the core when the transformer is in a no-load state (that is, there is no load on the secondary side); the latter refers to the total energy loss including copper loss in addition to the above-mentioned iron loss under rated load conditions. Through the accurate measurement of these two losses, the energy conversion efficiency and thermal management of the transformer can be fully understood. For example, abnormally high no-load loss may be due to poor quality of the core material or manufacturing process defects; while excessive load loss may indicate problems such as excessive winding resistance or unreasonable heat dissipation design.
It is worth noting that partial discharge measurement is also a key technology in measuring transformer maintenance. Partial discharge refers to the phenomenon of incomplete breakdown inside or on the surface of the insulating medium under the action of an electric field. Although the intensity of this discharge is small, if it exists for a long time, it will gradually erode the insulating material and eventually lead to insulation failure. Therefore, regular partial discharge testing can help to warn of potential risks in advance and take corresponding measures to prevent them. At present, commonly used detection methods include ultrasonic detection method, pulse current method, etc., each of which has its own characteristics and is suitable for the needs of different occasions.
Finally, the temperature rise test is crucial to evaluate the safety and stability of the transformer. The transformer will generate a certain amount of heat during operation. If the heat dissipation is poor, the internal temperature will be too high, affecting the life of the equipment and even causing a fire accident. The temperature rise test is designed to simulate the actual working conditions and monitor the temperature rise of each part of the transformer to confirm whether it meets the temperature rise limit specified in the relevant standards. This not only tests the cooling system design of the transformer itself, but also indirectly reflects the rationality of the overall structural layout.
In summary, measuring transformer covers many aspects from basic insulation performance to complex energy loss. Each test is directly related to whether the equipment can operate normally and its service life. By implementing a comprehensive and detailed measurement plan, not only can the reliability of the power system be improved and unexpected downtime be reduced, but it can also help reduce operation and maintenance costs and maximize economic benefits. Therefore, both manufacturers and users should attach importance to various transformer measurements to ensure the continuity and safety of power supply.