Design of Oil-Immersed Apparatus Oil Velocity Measure System Based on the Ultrasonic Wave Doppler Effect

Oil-immersed apparatus plays an important role in power grid. The Bruchholz relay is the most important component to detect transformer internal turn-to-turn short circuit fault. One of its most important functions are detecting the oil velocity to warn the potential risk or internal short circuit fault. However, the value of the relay setting is determined by experience, which is lack of convincing evidence. Thus, we designed an oil velocity measure system to monitor the oil velocity in power transformer. This system has fluid sensors which are based on Ultrasonic wave Doppler effect. By using proper devices, we build the system and also have developed the measure software. We used professional test platform to test it and installed it onto a power transformer, obtaining the data we need. Hence, we can identify if the system is useful for research the relay action.