A Non-contact Active Sensor for Detecting or Monitoring Electricity Transmission State of High Voltage AC Power Grid

In order to protect power engineers from being harmed unexpectedly, electricity transmission state of high voltage AC power grid needs detecting during the process of its examining and repairing. In order to ensure normal power energy transportation of high voltage AC power grid, its electricity transmission state also needs monitoring. Therefore, a non-contact active sensor for detecting or monitoring electricity transmission state of high voltage AC power grid is developed based on electromagnetic coupling. The developed active sensor is featured of a very concise circuitry structure, which is composed of a hybrid RMC net cascaded with a two stages active operation amplifier. Theoretic analysis indicates that the gain of the sensor approximately equal to the product of the gain of the two stages active operation amplifier and one third of the complex impedance of the RC branch in the hybrid RMC net. Experimental results indicate that the developed active sensor is capable of detecting or monitoring the electricity transportation state of AC power grid effectively at the distance above 42cm even for voltage as low as 220V/50Hz power grid or electric appliances.