"Winter Safety Guardian" - Home Electricity Grid Manager

Preface
Project Introduction
With the continuous growth of household electrical appliances, the demands on home power grids are also increasing. Every year, frequent electrical fires cause significant economic and property losses and loss of life. Our research has found that traditional circuit breakers can only trip in the event of extremely high current short circuits, and are powerless against aging circuits and low-power short circuits causing overheating. Therefore, we have added microcontroller control to the traditional circuit breaker, integrating FFT harmonic algorithms, sensor current monitoring, real-time early warning, temperature and humidity monitoring, and power grid fault algorithms. This allows for effective analysis and identification of electrical appliances, current monitoring of ultra-low power and overloaded appliances, and temperature detection of distribution boxes and lines to prevent overheating, overload, and short circuits, promptly eliminating potential safety hazards.

This project primarily uses an STM32F103 MCU as the main controller, with temperature and humidity sensors, smoke sensors, and current transformers as peripherals. Data is collected by the sensors and processed by the MCU. The MCU then uses our developed algorithms to make corresponding adjustments and handle events. FFT (Fast Fourier Transform) is used to calculate parameters such as phase angle and frequency to determine the type of electrical appliance. When an appliance is overloaded or short-circuited, the MCU reacts quickly, sending the collected data to a serial port display and uploading it to a mobile app via ESP8266 Wi-Fi. Using the STM32F103RCT6 MCU as the control core, combined with the high-precision three-phase energy metering chip HT7038, a single-phase electrical appliance analysis and identification device was designed and implemented. This device uses voltage and current transformers to acquire the electrical parameters of the line, connects to an HT7038 for proportional sampling of current and voltage, and transmits the electrical parameters to the STM32 main control chip via an SPI interface. It analyzes and identifies the characteristics of electrical parameters such as voltage, current, phase, active power, and power factor when the load is operating, and sends the results to a serial port screen for display. This device has two working modes: learning and analysis/monitoring. In learning mode, it tests and stores various electrical characteristic parameters of individual electrical appliances on the same line; in analysis/monitoring mode, it displays the type and operating status of various electrical appliances in real time. For nonlinear voltage and current, the accuracy can reach 0.1%, and the RMS value calculation accuracy of voltage and current can reach 0.2%.