Development of a Low Cost Power Meter Based on A Digital Signal Controller

The monitoring of power quality is a central topic for both household electrical and industrial equipment. Typically, the lacks of quality in a power system (both a public mains and an industrial power supply network) involve interruptions and deviations of the actual supply signals from the nominal characteristics, with potential annoying effects in electrical power systems and problems in industrial and communication apparatus. In this paper, the design and implementation of a measuring system based on a high-performance microcontroller that carries out the power quality analysis of the mains is presented. The system measures the fundamental parameters related to the system under monitoring, that can be a single or a three phase network. The proposed measurement instrument is mainly based on the Microchip PIC32MZ2048ECH100 Digital Signal Controller (DSC) and the Texas Instruments ADS8558 A/D converters (ADCs). Starting from voltage and current sampled values, simultaneously acquired by the converters, the DSC calculates the following parameters: frequency; RMS voltage; RMS current; phase shift; active power; reactive power; apparent power; THD. The measured parameters are also externally transmitted via a serial link. In the paper a prototype of the proposed instrument is described. It is linked to a PC and results shown on a LabVIEW based user interface, reporting also results from lab tests during the metrological characterization phase. Its main features (cost effectiveness, reduced dimensions and low power consumption) make it suitable for installation into existing electric cabinet of civil and commercial users. The continuous and real-time monitoring capability, managed both locally or remotely, is one of the most interesting features.