AC Electric Field Source Location Method Based On Multi-electric Field Sensors

The traditional method of electric field sensor to realize safe distance warning mainly indirectly realizes safe distance warning by setting a safety threshold,but the safety threshold corresponding to different voltage levels is different,and the safety threshold needs to be set in advance for each operation,thus bringing inconvenience and potential danger to the work.Therefore,aiming at the AC electric field,this paper proposes a method for locating the AC electric field source by a circular array of multi-electric field sensors,which can directly calculate the distance,elevation angle and azimuth angle between detector and hazard source,and is not affected by voltage level.The locating principle,locating error,optimal layout of sensors,hardware and software of detectors,and actual performance of detectors are studied and analyzed.1.The measuring principle of one-dimensional capacitive ball sensor is introduced by mirror image method,and the relation between the induced charge on the sensor surface and the electric field intensity at the measuring position is obtained.Based on the principle of electrostatic induction,the relationship between the induced charge on the sensor surface,the field source charge and the geometric position of the array is used to obtain that the field source induced charge has a quadratic inverse proportional relationship with the distance from the field source to the center of the array and a positive proportional relationship with the induced charge on the sensor surface,and a locating mathematical model is established.The causes of locating errors are analyzed: measurement errors and layout errors,and an error model is established.2.In order to obtain the best detector layout to reduce the mutual interference between sensors,the influence degree of different layout parameters on the locating error is simulated by error model,and the layout parameters include: sensor radius,array radius and sensor number.Then the constraint conditions and the objective function are established through the relationship among the mutual interference between sensors,the minimum induced charge amount and the locating error.Finally,the genetic algorithm can be used to calculate multiple field sources and quickly obtain the global optimal solution.The layout parameters of the detector are optimized.The optimization results show that the range of distance error is 8.4 ? 11.5% when the number of sensors on the circumference is 4,the array radius is 20 cm,and the sensor radius is 1.5cm.3.An electric field sensor structure with shielding ring is proposed,which can weaken the mutual interference between sensors and improve the consistency of sensors.The software and hardware of the detector are developed.The hardware includes: electric field measurement module and control system.The electric field measurement module consists of five flat circular electric field sensors and five matching conditioning circuits.The control system consists of a processor with STM32F030F4 microcontroller as its core and peripheral circuits.The software includes a software timer,a data acquisition module,a data processing module and a data transmission module.Finally,the detector can collect the signals of 5 sensors at the same time,and can realize the calculation of the positioning algorithm,and send the calculation results to the PC terminal through Bluetooth to display the coordinates.4.In order to verify the feasibility of the positioning method,experiments are carried out at 10 k V,35 k V and 110 k V alarm distances respectively.The experimental results show that the distance error is 0.18 m,the elevation error is 6.8,the azimuth error is 4.57,the distance error is 0.2m,the elevation error is 4.8,the azimuth error is 5.14 when the detector is located at the 10 k V alarm distance,which meets the safety distance warning requirements of 10 k V and 35 k V voltage levels.