Research And Implementation Of Wearable Electric Field Measurement System For Alarm Device

At present,as the voltage level of China's power grids continues to increase and the coverage of the power grid continues to expand,the structure of the grid becomes more and more complex,which causes serious security problems for live working staff and equipment,thus higher demands of safety management are raised.So it is useful for power system practitioners to design a kind of wearable electric field monitor device,which will send alarm signal when the electric field around practitioners is too strong.High-voltage equipment is often surrounded by strong electric field,which increases with the voltage level.To avoid direct or potential harm to the human body caused by the strong electric field,this paper proposes a method to monitor the electric field and send alarm signal when the field is too strong,thus providing security for the safety of practitioners.Comparing with the deficiency of the existing electric field measuring instrument for this problem,a kind of wearable electric field measuring instrument is proposed and a corresponding electric field sensor is developed.The availability of the proposed electric field sensor is verified by simulation and experiments,and alarm function is added to the wearable electric field measuring instrument to provide protection for the safety of power system practitioners.The main contents are as follows:(1)According to the requirements of wearable electric field measurement,a new type of double-spherical-shell electric field sensor is proposed.The influence of the sensor on the electric field distribution is analyzed by using the method of separation of variables.The relationship between the output voltage of sensor and the original electric field in space is analyzed,proving the feasibility of the sensor.(2)The measuring principle of the double-spherical-shell sensor and the influence of human body on the electric field are analyzed by simulation.Firstly,the feasibility of the double-spherical-shell sensor is verified and the influence of sensor size and material on the output voltage is analyzed,providing reference for the parameter determination of the sensor.After that,the influence of the human body on the electric field in the wearable electric field measurement is analyzed.And the installation site for instrument on body is suggested.(3)The hardware circuit and software system of the electric field measurement system are designed.Firstly,the signal extraction circuit is designed to convert the output signal of sensor into a ground signal.To extend the measurement range and reduce the complexity of the program,a RMS-DC converter circuit is designed.Through the program designing,the measurement voltage of the device is processed and the value of electric field in space is obtained.After comparing with the alarm threshold,the device will judge whether to send an alarm signal or not.(4)The experiment of the designed electric field measuring instrument is carried out.Firstly,a parallel plate type of electric field calibration system is built to calibrate the electric field measuring instrument.After that,the accuracy of the measuring instrument is verified in the single-phase analog line.Finally,a three-phase experiment platform is built to study the influence of human body on electric field and verify the performance of the wearable electric field measuring instrument.