There are two assessment items for power supply quality, one is power quality, and the other is power supply reliability. It can be seen that power quality and reliability are two concepts. If not modified,Power quality monitoringdeviceIf possible, there is no measurement of power supply reliability. To my knowledge, there is currently no equipment that can measure the reliability of power supply separately, because no one has counted the reliability of individual users, and most of them are based on the average power supply reliability of a region. Therefore, power supply reliability is mostly calculated through statistical calculations.

The power quality monitoring device can measure reliability, that is, it can record the total time a user has lost power, such as voltage monitors, smart energy meters, etc. Based on the total time of 8760 hours a year and the total time of power outage, the power supply reliability of that user can be calculated.Power quality mainly includes the quality of voltage, frequency, and waveform. The online monitoring equipment for power quality mainly measures voltage deviation, voltage fluctuation and flicker, frequency deviation, harmonics, voltage asymmetry, imbalance, etc.

Monitoring the reliability of power supply is also one of the important tasks. Power supply reliability refers to the ability of a power supply system to continuously supply electricity, which is an important indicator for assessing the quality of power supply system energy. It reflects the degree to which the power industry meets the national economic energy demand and has become one of the standards for measuring a country's economic development level.The reliability of power supply can be measured by a series of indicators: power supply reliability rate, average user outage time, average user outage frequency, and equivalent system outage hours.

At present, the reliability rate of power supply in general urban areas in China has reached over 3 9s (99.9%), and the average annual power outage time for users does not exceed 8.76 hours; The number of major urban centers has reached over 99.99%, with an average annual power outage time of no more than 53 minutes for users.The online monitoring system for power quality of State Grid began construction as early as 2012, unifying and centralizing the basic information previously dispersed in various provinces, cities, and business departments across the country, achieving data interconnection and breaking professional barriers.

The completion and operation of this project have achieved three transformations in the power quality management mode: from decentralization to centralization, from manual input to automatic collection, and from post statistics to online analysis, effectively reducing the burden on grassroots units and improving the accuracy and authenticity of data.

In fact, the power grid company has already clearly defined the route for the construction of the power quality monitoring system. The State Grid's "Notice on Issuing the Implementation Plan for the Construction and Promotion of the Power Quality Online Monitoring System" requires that by the end of 2014, the reliability of the power transmission and transformation system with a voltage level of 110 (66) kV and above, the frequency and voltage of the power grid, and the reliability data of the power supply for medium (high) voltage users within the city scope of the company's system should be achieved Automatic collection and online monitoring of power supply voltage data.

By the end of 2015, we will promote the new installation and renovation of collection devices in rural areas, and carry out automatic data collection of rural power supply voltage and reliability. Simultaneously based on the progress of promoting the coverage of low-voltage intelligent meters, carry out automatic collection of low-voltage user power supply reliability data, and conduct pilot research on evaluation and analysis of low-voltage user power supply reliability.