At present, there is a lack of effective means to observe the growth and development of electrical branches growing inside opaque insulating materials such as oil-soaked cardboard in real time, which hinds the corresponding local defect diagnosis and insulation fault warning.  The two-dimensional boundary electric field measurement system proposed in this paper can realize the long time real-time detection of the growth process of electric branches on the two-dimensional plane.
       Two STM32 chips are used as control, acquisition and storage chips respectively.  The control chip sends PWM wave to control the 8-choice analog switch 74HC4051 to expand the ADC channel. The acquisition and storage chip collects voltage signals at the sampling point in real time and stores the collected data to the USB disk with its own USB OTG HS function module.  The signal sent by the signal generator is used to replace the voltage signal of the sampling point to verify the function realization degree of the system, and the back-end LABVIEW software is used to draw the waveform of the collected data.
      A two-dimensional boundary electric field measurement system with 72 sampling points and high sampling rate and fast and long time storage is established. Based on this system, a combination of a control chip and several acquisition and storage chips can be designed to expand the sampling points to hundreds and achieve a larger range of measurement.


 

electrical tree detection,STM32,data collection and storage