Design Of Multifunctional Near Electricity Warning Wristband

As a commonly used non-contact electroscope,the near electricity warning device has been widely used in electric power maintenance sites.When the equipment is in the power-on state,the near electricity warning device can send out a warning signal when the operator crosses a safe distance to remind the operator to retreat to a safe area.At present,the principle and technology of near electricity warning devices for non-contact electricity detection are relatively mature,but there are still some shortcomings,such as the problem that operators easily forget to carry and inconvenience,inconvenient gear adjustment,and single function.As the improving level of safety management,the need for real-time and diversified functions of near electricity early warning devices is becoming more and more significant.Therefore,the development of a lightweight,portable,and feature-rich wristband-type near electricity warning device is of great significance to the security of operators.Taking the induction phenomenon and distortion field as the starting point,the thesis determines that the induction antenna is used as the electric field sensor,establishes an equivalent circuit and determines the design size of the induction antenna;Using Maxwell simulation to analyze the distortion of the electric field around the human body,assess the extent to which the human body’s walking process or small swing arm movement affects the electric field,and verify that the wrist-type electric field detection is feasible to achieve near-electrical early warning;The image charge method is used to analyze the electric field distribution of the power line.And simulate various working conditions of the power line in Maxwell to obtain different field strength distribution curves;Design each module circuit and PCB,complete the bracelet hardware production,write software and perform system debugging.In the signal conditioning circuit,the electric field strength signal output by the induction antenna is sent to the analog-to-digital conversion pin of the MCU after active filtering,precision rectification,and program-controlled amplification;The MCU performs digital filtering,calculation and comparison on the collected signals,determines whether to output an alarm signal to alert the operator.In order to facilitate maintenance monitoring,the wristband has wireless communication function.The data can be uploaded to the guard and monitoring platform APP via Bluetooth.The monitoring staff can view the real-time data through the APP field strength dashboard.In addition,the APP can present the field strength data on the observation path as a line chart.It can help users judge the operation of power lines according to the characteristics of the curve.Four sets of experiments were performed on the designed near electricity warning wristband,including simulation test experiment,calibration experiment,wear measurement experiment and electric field distribution characteristic monitoring experiment.Among them,in the wear measurement experiment,the human body wears the wristband to perform a linearity experiment,a measurement of distance change,and the experiment of the effect of swinging arm,respectively.The simulation test experiment result shows that the signal conditioning circuit of the inductive antenna has good linearity,and the linearity between the input and output signal voltages is close to 1.0;The correction coefficient obtained through the correction experiment is 43.36;The near electricity warning wristband can alarm in time at a safe distance of 0.7m,realizing the warning function for electric power workers.During the swing of the human arm,the average value of the bracelet reading at each angle is 395.6mV,the standard deviation is 18.3mV,the coefficient of variation is 4.6%,and the detection stability is good.In the electric field distribution characteristic monitoring experiment,an electric field distribution curve with obvious outline characteristics is obtained,which meets the simulation characteristics,and proves that the function is available.In summary,the designed multi-function wristband can realize functions such as near electricity early warning,electric field distribution characteristic monitoring,time display,and mobile phone APP monitoring,etc.,which has achieved the intended purpose and requirements,and it provides workers in a high-voltage environment with more active and effective power safety protection.