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As we all know, in power systems, high-voltage transformer oil plays a role in insulation, heat dissipation and arc extinguishing during transformer operation. The oil level in the transformer oil conservator is an important basis for judging the normal operation of the transformer. The level of oil level directly affects the cooling effect & insulation performance of the transformer. Therefore, it is crucial to correctly read the oil level of the transformer oil level gauge.
Working principle of transformer oil level gauge.
With the continuous development of the electric power industry, 500kV transformers have become the main transformers of power grids in various countries. They have the characteristics of high cost, large size and large amount of oil. Sufficient oil volume and accurate and reliable oil level are the prerequisites for ensuring the stable operation of the transformer. . At present, the oil level in most transformer oil conservator tanks is obtained through infrared thermometers or electromagnetic oil level gauges.
1, Problem
There is obvious oil leakage at the butterfly valve interface of the C-phase body of the No. 2 main transformer of a 500kV substation. The oil leakage is as shown in the figure. After analysis, the oil leakage was caused by the aging of the O-ring rubber in the butterfly valve, which has been in a compressed state for a long time and lost its elasticity. Since the time and amount of oil leakage are unknown, it is necessary to measure the oil level of the main transformer oil conservator after replacing the O-ring to check whether the oil level in the oil conservator meets the requirements for safe operation.
2. Program analysis
At present, commonly used methods for measuring oil level in oil conservator include infrared temperature measurement method, electromagnetic oil level gauge and other methods. This article proposes a new method of measuring oil level in transformer oil conservator based on the principle of ultrasonic detection.
(1) Infrared thermometer to measure oil level.
The principle of infrared temperature detection transformer oil level is through the oil storage cabinet surface contact oil and contact capsule location of different temperatures, the use of infrared temperature sensing effect to measure the surface temperature of the oil storage cabinet, through the infrared thermometer images taken, color analysis to determine the actual transformer oil level. Infrared thermometer by the environment, space, temperature, the influence of a relatively large, when the temperature difference between the air temperature and the oil temperature is small, low load, the location of the oil level line shot fuzzy, difficult to identify. Figure 2 for the use of this method measured the transformer oil conservator oil level.
(2) Electromagnetic oil level gauge. The electromagnetic oil level gauge is a commonly used oil level measuring device for large and medium-sized transformer oil conservators that comes with transformers. Its basic principle: when the oil level in the oil conservator changes, the float on the connecting rod of the oil level gauge (located in the oil conservator) swings up and down, driving the rotating mechanism of the oil level gauge to rotate. Through the magnetic coupling and pointer shaft Turn the oil conservator and the oil level in the oil conservator will be indicated by the pointer on the dial. Since the 500kV transformer is in a strong magnetic field and perennial vibration state, the magnetic coupling system and pointer transmission system are easily affected, thus affecting the accuracy of oil level measurement in the oil conservator.
(3) SKE transformer oil level ultrasonic detector sensor, fixed oil level transmitter and portable rod-type oil level transmitter.
The traditional way of oil conservator level detection is time-consuming and labor costly. While this fixed dedicated oil level sensor developed by SKE can obtain accurate oil level information at any time without opening the oil conservator.
This solution adopts the principle of ultrasonic measurement and uses a magnetic suction probe to achieve instant use. It can be used with solar panels to work outdoors for a long time to obtain oil level information, getting rid of the traditional measurement method of observing the oil level roughly only.
Main Features:
- High accuracy of 2mm
- No need to stop the main transformer, then can test easily
- No need to contact the oil directly, non-destructive detection, high safety
- Avoid the fault of oil level sensor jamming and incorrect indication.
- Convenient to view different waveforms, easy to use.
