With the development of society, power quality issues are increasingly receiving attention from society. The reasons are not only related to the power sector, but also some power quality indicators (such as harmonics, voltage fluctuations and flicker, three-phase voltage imbalance) are often caused by user interference, involving the power generation, supply, and consumption parties, and related to the interests of all parties. Therefore, in order to effectively safeguard the common interests of the power sector and power users, ensure the safe operation of the power grid, and purify the electrical environment, it is necessary to strengthen the management of power system power quality, establish a comprehensive power quality monitoring and analysis system, in order to accurately detect, evaluate, and classify power quality. The development and improvement of power quality monitoring technology are related to the safety issues of the power grid and electricity consumption. Introduction: Power quality is not only related to the safe and economic operation of power grid enterprises, but also affects the safe operation of users and product quality. The integration of a large number of distributed energy sources, such as wind and solar power, will further deteriorate the quality of electricity. The continuous monitoring, analysis and evaluation of power quality information is a prerequisite for discovering power quality problems and improving the level of power quality. The Power Quality Monitoring System (hereinafter referred to as the "Monitoring System") utilizes power quality monitoring terminals installed on the power grid or user side (hereinafter referred to as the "Monitoring Terminal") to transmit monitoring data back to the monitoring center (monitoring master or sub station) through the network, achieving simultaneous monitoring of multiple locations and publishing power quality related information. It is an effective means of power quality monitoring and evaluation. [2] The objectives and key points of power quality monitoring: The monitoring objectives determine the selection of monitoring equipment, triggering threshold, data collection and storage methods, and analysis and interpretation requirements. Any power quality monitoring system should have clear monitoring objectives, including: 1) describing the overall performance of the system. 2) Describe specific power quality issues. 3) Evaluate the level of power quality. 4) Interference diagnosis and equipment maintenance. The key points of power quality monitoring include: 1) determining the description and analysis method of power quality. 2) Select a monitoring point. Generally speaking, measuring at several key points can determine the characteristics of the entire system. The monitoring location is usually selected at the user's power supply entrance, near the affected equipment, or simultaneously monitoring at the substation and specific user power supply entrances