Smart meter impact test - voltage imbalance impact test

Voltage imbalance refers to the situation where the A, B, and C phases of a three-phase power supply have different voltages (such as one phase having electricity and the other two phases having no electricity, or two phases having electricity and one phase having no electricity), which may occur in actual power grids.      

The core of this experiment is to verify whether the measurement accuracy of three-phase smart meters is qualified in the case of "uneven voltage", ensuring accurate measurement even in complex power grid environments.

8.1 Test conditions: 8.1.1 Temperature 23 ℃± 2 ℃, humidity 45% RH~75% RH 8.1.2 Testing equipment: Three phase smart meter calibration table 8.1.3 Disconnect the power supply of the smart meter first, and live operation is strictly prohibited. 8.2 Precautions: A. In the power-off state, manually disconnect the voltage and current signal lines behind the calibration table (direct adjustment of the operation panel is strictly prohibited), and connect them according to the following requirements: 8.2.1 First, adjust the calibration table to the following situations: a) A adds the rated voltage, B and C phase voltages are 0, and the current is also 0.

b) B adds up the rated voltage, A and C phase voltages are 0, and the current is also 0. c) C adds up the rated voltage, A and B phase voltages are 0, and the current is also 0. d) The rated voltage of AB is added, the voltage of phase C is 0, and the current is also 0. e) The rated voltage of B and C is added together, and the voltage of phase A is 0, and the current is also 0. f) The rated voltage of A and C is added together, and the voltage of phase B is 0, and the current is also 0. B. After completing the wiring for each situation, power on the smart meter and set the test parameters: load current Ib, power factor 1. C. Start the calibration bench and wait for the data to stabilize. Accurately record the error values under this operating condition and observe the meter throughout the entire process without any abnormalities (such as screen flickering, crashes, or errors). D. After testing one situation, power off first, then switch to the next wiring, repeat the above steps until all six situations are tested. 8.2.2 When using a three-phase three wire system, adjust the calibration table to the following situations: a) Add AB to the rated voltage, C phase voltage is 0, and current is also 0. b) The rated voltage of AC is added, and the B-phase voltage is 0, and the current is also 0. C) The rated voltage of BC is added, the voltage of phase A is 0, and the current is also 0. Record the error of Ib current and power factor of 1 in each situation. After all scenario tests are completed, power off and disconnect the wires, restore the signal wires of the verification table to their original positions, and ensure that subsequent tests are normal. 8.2.4 Organize all error records, fill in the test conclusion (indicating whether the errors of each working condition are qualified or specific abnormalities), register equipment maintenance records, and complete the test. 8.3 Precautions: In actual operation, the voltage and current signals behind the test bench should be disconnected as required, rather than directly adjusting the operation panel. When disconnecting the signal line, it must be done when the meter is not powered on.