强无线电干扰对智能电能表的影响

Influence of high-power radio interference on intelligent ammeter

在强无线电干扰下智能电能表会出现计量负误差甚至丧失计量功能等现象,强无线电干扰撤除后,智能电能表能恢复正常计量,这种窃电行为十分隐蔽且无法取证,给电力企业带来重大经济损失。在分析电磁干扰对电子线路影响的基础上,研究了强无线电干扰导致智能电表程序跑飞而丧失计量功能,以及计量芯片参考电压源漂移而导致计量出现负误差的机理。并通过强无线电干扰对智能电表影响的实验验证了理论研究结果的正确性。研究结果表明,强无线电干扰下,一方面智能电表CPU(central processing unit)程序跑飞,看门狗电路反复复位,智能电表丧失计量功能;另一方面,智能电表印刷线路板的布线耦合无线电信号,产生感应电压,使计量芯片模数转换模块参考电压上升,造成转换结果偏低导致电能计量出现负误差,实验中,当参考电压由2.4 V上升至2.8 V时,引起计量负误差高达26.6%。该研究成果对智能电表的防窃电设计具有指导意义。

Under high-power radio interference,some phenomena such as negative metering error or even out of function will appear on intelligent ammeter.After the removal of the interference,the intelligent ammeter will return to normal metering mode.This kind of electricity theft is strongly concealed and hard to track,which results in a large number of economic losses to power enterprises.Based on the analysis of the influence of electromagnetic interference on electronic circuits,this article researches the phenomenon that the high-power radio interference causes the intelligent ammeter program to run away and lose its metering function and the mechanism that the reference voltage source drifts of the metering chip can cause a negative metering error.The test of the influence of high-power radio interference on the intelligent ammeter verifies the correctness of the theoretical research results.The result shows that under the high-power radio interference,on one hand,the CPU(central processing unit)program of intelligent ammeter runs away,the watchdog circuit resets repeatedly,and the intelligent ammeter loses the metering function;on the other hand,the wiring of printed circuit board of the intelligent ammeter couples the radio signal to generate an induced voltage,which causes the reference voltage of the AD(analog-to-digital)module of the metering chip to rise,resulting in a low conversion of AD and a negative error in energy metering.In the test,when the reference voltage rises from 2.4 V to 2.8 V,the negative metering error can be as high as 26.6%.The research results of this article have a guiding significance for the anti-electricity theft design of intelligent ammeters.