Research On Non-contact Electric Field Coupling Measurement And Energy Acquisition Technology

With the continuous progress of the power industry and the booming development of smart grids,more and more multifunctional integrated devices are used in the power system.Due to the measurement of voltage analog signals as its core module,higher requirements are put forward for voltage sensors.Traditional voltage transformers,due to their iron core structure,are prone to ferromagnetic saturation and affect measurement quality.At the same time,due to their large volume,they cannot be matched with current intelligent electrical equipment.Therefore,there is an urgent need for a small,lightweight,and widely applicable voltage sensor.In response to this issue,this article studies a micro voltage sensor that integrates measurement and self energy acquisition.While significantly reducing the volume of the voltage sensor,it can also ensure a large bandwidth and high linearity,meeting the current needs of most electrical equipment for voltage measurement.Firstly,research will be conducted on the theory of non-contact voltage measurement and self powered methods.Theoretical analysis was conducted on the basic principles of electric field coupling measurement and energy harvesting,and based on this,a model for electric field coupling measurement and its equivalent circuit were proposed.In response to the issue of electric field measurement being susceptible to environmental interference,a differential structure was adopted to optimize the sensor,effectively reducing the impact of environmental factors on the accurate measurement of the sensor.Derive the transfer function based on the equivalent circuit diagram of the differential structure sensor,and then derive the condition for the constant transformation ratio of the sensor.Through comprehensive analysis of four indicators,epoxy resin was selected as the insulation material for the sensor.In order to overcome the wave energy loss caused by impedance mismatch during signal transmission,the sensor is designed as a high-frequency and power frequency dual channel measurement mode,which solves the problem of refraction and reflection during signal transmission caused by impedance mismatch.Secondly.an experimental platform for electric field coupling power frequency,high-frequency measurement,and electric field energy harvesting was established.Regarding the two key parameters,parallel resistance and parallel capacitance.which affect the measurement of electric field coupling,the impact of each parameter on the voltage sensor is analyzed in depth,and the optimal parameter combination suitable for low-voltage distribution lines of lOkV and below is given.The bandwidth of the voltage sensor measured by the frequency response analyzer is between 30Hz and 200kHz.Finally,actual measurements were conducted on overhead lines and cables,and the linearity of the sensor was determined by analyzing the experimental data,and evaluated using nonlinear error indicators.Finally,the maximum power point at which the sensor can self generate energy is found through experiments.The maximum self powered power of the sensor measured in an overhead line environment is 12.16mW,and the maximum self powered power in a cable environment is 472.82mW.Taking into account the impact of the environment on the sensor function,experiments were conducted,and the results showed that rainwater weather had adverse effects on the energy consumption power,sensor waveform quality,and sensor linearity of the electric field board.The expected solutions were provided.