Power quality monitoringdeviceWhat aspects can be monitored?

1Voltage deviation, national standardGB/T 12325-2008According to the "Power Quality and Supply Voltage Deviation":35kVThe sum of the positive and negative deviations of the power supply voltage and above shall not exceed the rated voltage10%；10kVThe allowable deviation of three-phase power supply voltage below and below is ± of the rated voltage7%；220VThe allowable deviation of single-phase power supply voltage is-10%~+7%。

2Harmonics in public power grids, national standardGB/T14549-1993Power Quality According to "Harmonics in Public Power Grid":6~220kVThe total harmonic distortion rate of voltage (phase voltage) in public power grids at all levels is:0.38kV为5%，6~10kV为4%，35~66kV为3%，110kV为2%; The allowable value of harmonic current injected into the power grid by users should ensure that the harmonic voltage of all levels of the power grid is within the limit range. Therefore, according to the national standard, the voltage harmonic distortion rate generated by harmonic sources of all levels of the power grid is:0.38kV为2.6%，6~10kV为2.2%，35~66kV为1.9%，110kV为1.5%. right220kVThe power grid and its power supply users refer to this standard110kVExecution.

3Unbalanced three-phase voltage, national standardGB/T15543-2008Power Quality According to the regulation of "three-phase voltage imbalance", the allowable value of normal voltage imbalance at the public connection point of the power system is2%For a short period of time, it should not exceed4%; For each user of a public connection point, the allowable value that causes voltage imbalance at that point is generally1.3%For a short period of time, it should not exceed2.6%。

4Power system frequency deviation, national standardGB/T15945-2008Power Quality According to the "Power System Frequency Deviation", the nominal frequency of China's power system is50HzThe allowable deviation of normal frequency in the power system is: ±0.2HzWhen the system capacity is small, the deviation can be relaxed to ±0.5HzThe standard does not specify the limits of system capacity size. In the National Power Supply Regulations, it is stipulated that the allowable deviation of the power supply frequency of the power supply bureau: the capacity of the power grid isthree hundred± for 10000 kilowatts and above0.2HzThe power grid capacity isthree hundred± for those below 10000 watts0.5Hz。

5Voltage fluctuation and flicker, national standardGB/T12326-2008Power Quality According to "Voltage Fluctuation and Flicker":Power quality monitoring deviceAccording to the standard, the public connection point of the power system is required for a long time（2Hour flicker valuePltMeet: ≤110kV，Plt=0.1；>110kVWhen,Plt=0.8。