Power quality monitoringdeviceMainly including voltage, frequency, and waveform quality. Mainly measuring voltage deviation, voltage fluctuation and flicker, frequency deviation, harmonics and voltage asymmetry, imbalance, etc. Monitoring power supply reliability is also an important task. Power supply reliability refers to the ability of the power supply system to continuously supply power, and is an important indicator for assessing the power quality of the power supply system. It reflects the degree to which the power industry meets the electricity demand of the national economy, and has become a standard 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.

Electricity quality refers to the quality of electricity in the power system. The ideal electrical energy should be a symmetrical sine wave. Some factors can cause the waveform to deviate from the symmetrical sine, resulting in power quality issues.Strictly speaking, the main indicators for measuring power quality include voltage, frequency, and waveform. In a general sense, it refers to power supply, including four related terms and concepts: voltage quality, current quality, power supply quality, and power consumption quality.

Under the predetermined operation mode of the power system, using the power quality detection method specified in the standard, applying the power quality monitoring equipment that meets the standard, testing the power quality interference indicators of the designated power supply (node), and applying the data evaluation method that meets the standard or is widely recognized, the power quality evaluation results for the node are obtained. The results are compared with national or industry standards, To determine whether its power quality indicators exceed the standard.