变电设备智能物联超声局部放电微型化测量转换电路

Miniaturized Measurement Conversion Circuit for Ultrasonic Partial Discharge in Intelligent IoT of Substation Equipment

针对变电设备智能物联监测中的分布式智能感知节点微型化设计需求,设计了一种新型的超声局部放电测量转换电路。使用高集成度仪表放大电路对高阻抗的超声局部放电传感器输出信号进行了低阻抗变换和固定增益放大,设计通带为20~300 kHz的宽带滤波电路以适应变电设备上带宽不同的传感器,最后通过增益可调仪表放大电路适应不同灵敏度的传感器输出信号。电路能同时连接2个超声局部放电传感器并对其测量信号进行转换,电路尺寸为83 mm×50 mm×15.5 mm。设计了相应的电路性能测试实验并给出了其在智能物联系统中的应用方法。实验结果表明:电路各级增益误差在整个通带频段内低于1%,1000倍增益条件下的输出端噪声RMS值不超过10 mV。

Aiming at the demand for miniaturization of distributed intelligent sensing nodes in intelligent Internet of Things(IoT)monitoring of substation equipment,a novel measurement conversion circuit for ultrasonic partial discharge was designed.A high-integration instrument amplifier circuit was used to perform low-impedance transformation and fixed-gain amplification of the output signals from[JP2]high-impedance ultrasonic partial discharge sensors.A broadband filter circuit with a passband of 20~300 kHz was designed to adapt to sensors with different bandwidths on substation equipment.Finally,a gain-adjustable instrument amplifier circuit was used to adapt to the output signals of sensors with different sensitivities.The circuit was able to connect two ultrasonic partial discharge sensors and convert their measurement signals simultaneously,while the size of the circuit was 83 mm×50 mm×15.5 mm.This paper presented corresponding circuit performance testing experiments and provided the application method of the circuit in an intelligent IoT system.The experimental results show that the gain error of each stage of the circuit is lower than 1%throughout the passband,and the output noise RMS value under a 1000-fold gain condition is within 10 mV.