工频电磁环境监测仪电磁兼容设计

Design of electromagnetic compatibility of power-frequency electromagnetic environment monitor

针对输变电工程环评工作对电磁环境监测仪精度要求日益提高的问题,设计了一种高精度工频电磁环境监测仪.首先通过分析电容性耦合原理,分析出仪器内部电磁干扰产生原因是供电电源、高频微处理器和晶振电路;其次通过具体措施抑制如供电模块选择、线路布局和传感器选择等电磁兼容技术抑制仪器内部产生的电磁干扰,并以传输线理论为基础分析屏蔽体对电磁波的衰减,设计铝质屏蔽体减小外界环境中的电磁干扰;最后通过电磁兼容及校准实验证明:经过电磁兼容设计,电磁场监测误差在测量量程内保持在1%以内,监测精度较高,可满足输变电工程电磁环境监测的建设需求,为输变电工程电磁环境实时监测和数据积累提供有力支撑.

Aiming at the problem of increasing accuracy demand of electromagnetic environment monitor for power transmission and transformation project, a high-precision power-frequency electromagnetic environment monitoring instrument is designed in this paper. First of all, by analyzing the principle of capacitive coupling, they can conclude that the internal electromagnetic interference is caused by power supply mod- ule, high-frequency microprocessors and crystal oscillator circuit. Secondly, through specific suppression measures such as the power supply module selection, circuit layout , sensor selection and other electromagnetic compatibility technology, they can suppress the internal electromagnetic interference generated by the instrument itself. Based on the transmission line theory, a aluminum shield is designed to attenuate electromagnetic wave generated by outside electromagnetic interference. Finally, the electromagnetic com- patibility and the calibration experiment proves that after the electromagnetic compatibility design, the error of electromagnetic field monitor in the test range is less than 1%. Higher monitoring accuracy can meet the demand of the electromagnetic environmental monitoring; and it can provide real-time monitoring data for the power transmission.