How to optimize the design of measuring transformer cooling system through temperature rise test?
Release Time : 2025-04-22
Temperature rise test is the core means to verify the rationality of measuring transformer design and the efficiency of cooling system. Its core goal is to obtain the dynamic change law of key parameters such as winding, core and oil temperature by simulating real load conditions, so as to provide data support for cooling system optimization.
Temperature rise test must strictly follow the standard process to ensure data accuracy. The test needs to run continuously at rated capacity until the oil top temperature and the winding hot spot temperature reach a stable state (temperature rise ≤1K per hour). The internal and surface temperature distribution of measuring transformer can be collected synchronously through high-precision fiber optic temperature measuring device and infrared thermal imager. For strong oil circulation cooling system, it is necessary to focus on monitoring the charged characteristics of oil flow to avoid local overheating caused by oil flow discharge.
Data analysis needs to combine thermodynamic model and simulation technology. Based on the test data, a three-dimensional temperature field model of measuring transformer can be established to quantify the matching relationship between winding loss, core eddy current loss and cooling system heat dissipation capacity. For example, through finite element analysis, it was found that the hot spot temperature rise of a high-voltage winding of a measuring transformer exceeded the standard by 15K. The root cause was that the unreasonable design of the oil channel led to insufficient local oil flow speed. Further analysis of the dissolved gas data in the oil (such as abnormal increase in H2 content) can reversely verify the existence of the oil flow electrification phenomenon.
Design optimization requires solutions to specific problems. For the excessively high temperature rise of the winding hot spot, the winding structure can be optimized (such as adding longitudinal oil channels), the oil flow direction can be adjusted, or the cooler specifications can be upgraded (such as using heat pipe radiators instead of traditional plate radiators). For the problem of oil flow electrification, the oil circuit design needs to be optimized (such as reducing the oil speed, improving the surface finish of the insulating material) and adding a deionizer. By comparing the temperature rise data under different cooling schemes, the effect of design improvement can be quantitatively evaluated. For example, by increasing the cooler capacity from 125kW to 200kW, the hot spot temperature rise of the winding of a 500kV measuring transformer was reduced from 85K to 70K, significantly improving the overload capacity of the equipment.
A closed-loop verification mechanism needs to be established. The optimized cooling system needs to be retested for temperature rise, and the temperature rise curves, noise levels, and dissolved gas data in the oil before and after the improvement need to be compared. For example, after a measuring transformer uses a heat pipe radiator, the temperature rise of the winding hot spot is reduced, the load noise is reduced from 65dB to 58dB, and the growth rate of furfural content in the oil is slowed by 30%, which verifies the effectiveness of the design optimization.
The temperature rise test is not only a tool for measuring transformer performance verification, but also a data engine for cooling system optimization. Through precise testing, in-depth analysis and iterative design, the efficiency, lightweight and intelligent upgrade of the measuring transformer cooling system can be achieved, providing a solid guarantee for the safe and stable operation of power equipment.
Temperature rise test must strictly follow the standard process to ensure data accuracy. The test needs to run continuously at rated capacity until the oil top temperature and the winding hot spot temperature reach a stable state (temperature rise ≤1K per hour). The internal and surface temperature distribution of measuring transformer can be collected synchronously through high-precision fiber optic temperature measuring device and infrared thermal imager. For strong oil circulation cooling system, it is necessary to focus on monitoring the charged characteristics of oil flow to avoid local overheating caused by oil flow discharge.
Data analysis needs to combine thermodynamic model and simulation technology. Based on the test data, a three-dimensional temperature field model of measuring transformer can be established to quantify the matching relationship between winding loss, core eddy current loss and cooling system heat dissipation capacity. For example, through finite element analysis, it was found that the hot spot temperature rise of a high-voltage winding of a measuring transformer exceeded the standard by 15K. The root cause was that the unreasonable design of the oil channel led to insufficient local oil flow speed. Further analysis of the dissolved gas data in the oil (such as abnormal increase in H2 content) can reversely verify the existence of the oil flow electrification phenomenon.
Design optimization requires solutions to specific problems. For the excessively high temperature rise of the winding hot spot, the winding structure can be optimized (such as adding longitudinal oil channels), the oil flow direction can be adjusted, or the cooler specifications can be upgraded (such as using heat pipe radiators instead of traditional plate radiators). For the problem of oil flow electrification, the oil circuit design needs to be optimized (such as reducing the oil speed, improving the surface finish of the insulating material) and adding a deionizer. By comparing the temperature rise data under different cooling schemes, the effect of design improvement can be quantitatively evaluated. For example, by increasing the cooler capacity from 125kW to 200kW, the hot spot temperature rise of the winding of a 500kV measuring transformer was reduced from 85K to 70K, significantly improving the overload capacity of the equipment.
A closed-loop verification mechanism needs to be established. The optimized cooling system needs to be retested for temperature rise, and the temperature rise curves, noise levels, and dissolved gas data in the oil before and after the improvement need to be compared. For example, after a measuring transformer uses a heat pipe radiator, the temperature rise of the winding hot spot is reduced, the load noise is reduced from 65dB to 58dB, and the growth rate of furfural content in the oil is slowed by 30%, which verifies the effectiveness of the design optimization.
The temperature rise test is not only a tool for measuring transformer performance verification, but also a data engine for cooling system optimization. Through precise testing, in-depth analysis and iterative design, the efficiency, lightweight and intelligent upgrade of the measuring transformer cooling system can be achieved, providing a solid guarantee for the safe and stable operation of power equipment.