Microcontroller Based Magnetometer for Smart Meters Used in Electrical Energy Measurement

In this paper is presented the implementation of a versatile magnetometer which is designed for applications in the field of electrical energy measurement, especially for smart meters used in advanced metering infrastructure. The magnetometer is the key element in a smart meter, performing contactless current sensing for precise power consumption computation. The proposed system uses a magnetic sensor with a sensitivity of 2.5 mV/Gauss and a measurement domain of 0-1000 Gauss. All the initial processing of the signal generated by the magnetic sensor, as well as other specific functionalities required by the magnetometer's operation, like calibration and self testing, are realized with PIC16F876A microcontroller and few other complementary analog conditioning circuits. The connectivity of the equipment is ensured by a local RS232 interface and a Telit GE864 GSM/GPS module that allows the integration of the proposed microsystem into a larger smart grid. The innovative design of the proposed magnetometer relies on the intrinsic flexibility and reconfigurability offered by the microcontrollers technology, correlated with the advantages of the GSM interface which resulted in a efficient implementation solution that facilitate the development of intelligent electricity metering networks.