Digital measurement device for monitoring the main characteristics of the power grid

Abstract

During the operation of various equipment in electrical grids, there is a deviation from the rated voltage value, as well as continuous changes in current and power consumption. In this case, there is a requirement for regular monitoring of the power grid main parameters, which can be used to make decisions on optimizing the operation of its components. To solve this task, the research analyzed the methods and equipment for measuring the main indicators of the electrical grid, developed a measurement methodology and created a digital measuring system for monitoring the main indicators of a single-phase electrical grid with a voltage of 220 V using the PIC18F2525 microcontroller from Microchip. To measure the phase angle between the voltage and current signals, the signal crossing detection scheme Zero Crossing Detector with comparators is used. The program code was written in Microchip's MPLAB X IDE using the XC8 compiler of the C++ programming language and lists of basic functions for calculating the parameters of the electrical grid are given. The proposed device measures the root mean square value of voltage and current; total, active and reactive power; power factor and frequency of the input voltage. The measuring system allows real-time determination of the main characteristics of the power grid with an effective voltage value up to 280 V and an effective current value up to 50 A and their visualization on a symbolic LCD display. The article demonstrates the operation of the device in the programs for simulating electronic circuits NI Multisim and Proteus Design with different types of loads: resistive, resistive-inductive, and resistive-capacitive.