Three-phase four-wire load star connection circuit

Three-phase four-wire power supply, load star connection (i.e. ‰ connection). For a three-phase asymmetric
load, use three single-phase power meters to measure. The measurement circuit is as shown in the figure. The reading of the three single-phase
power centers is wl , wz, W3, then the three-phase power P=W] +Wz+Wa,
    this measurement method is called j wattmeter method; for three-phase symmetrical load, it can be measured with a single-
phase power meter. If the reading of the power meter For W． Then the three-phase power is P-3W, which is called the wattmeter
method.