Specific indicators of V cone flowmeter power quality analyzer

Voltage deviation

　　GB/T 12325-2008 " V-cone flowmeter " stipulates: The sum of the absolute values ​​of the positive and negative deviations of the power quality analyzer's 35kV and above power supply voltage shall not exceed 10% of the nominal voltage; the allowable deviation of the three-phase power supply voltage of 20kV and below is ±7% of the nominal voltage; the allowable deviation of the 220V single-phase power supply voltage is +7%, -10% of the nominal voltage.

Three-phase voltage unbalance

　　GB/T15543-2008 "Three-phase Voltage Unbalance for Power Quality" stipulates that the voltage unbalance limit at the common connection point of the power system is: when the power grid is operating normally, the negative sequence voltage unbalance shall not exceed 2%, and shall not exceed 4% in a short time; the zero sequence voltage limit of the low voltage system is not specified for the time being, but the voltage of each phase must meet the requirements of GB/T 12325. The allowable value of the negative sequence voltage unbalance caused by each user connected to the common connection point is generally 1.3%, and shall not exceed 2.6% in a short time.

Utility grid harmonics

　　GB/T14549--93 "Power Quality - Harmonics in Public Grids" stipulates that the total harmonic distortion rate of the voltage (phase voltage) of the public grids at all levels from 6 to 220 kV is 5.0% for 0.38 kV, 4.0% for 6 to 10 kV, 3.0% for 35 to 66 kV, and 2.0% for 110 kV; the permissible value of the harmonic current injected into the grid by the user should ensure that the harmonic voltage of the grid at all levels is within the limit range, so the national standard stipulates that the total harmonic distortion rate of the voltage generated by the harmonic source of the grid at all levels of the power quality analyzer is: 2.6% for 0.38 kV, 2.2% for 6 to 10 kV, 1.9% for 35 to 66 kV, and 1.5% for 110 kV. For the 220 kV grid and the power users it supplies, refer to this standard for 110 kV.

Fluctuation and flicker

GB/T 12326-2008 "Power Quality Voltage Fluctuation and Flicker" stipulates that at the common connection point of the power system of the power quality analyzer, under the minimum mode of normal system operation, with one week ( V-cone flowmeter ) as the measurement cycle, all long-term flicker values ​​Plt shall meet the following requirements: ≤110kV, Plt=1; >110kV, Plt=0.8.