Influence on power distribution panel and low voltage lines

    (1) the three-phase unbalanced load will increase the loss of line:

    Three-phase four wire power supply line, the load average assigned tothree phase, with current per phase is I, the neutral line current is zero,the power loss is: Δ P1 = 3I2 The maximum unbalance, namely, a phase of 3I, the other two are zero,the neutral line current is 3I, the power loss is: Δ P2 = 2 (3I) 2R = 18I2R = 6 (3I2R) The maximum unbalance power loss is 6 times the balance, in other words, if the maximum unbalance monthly loss of 1200 kWh, theequilibrium when the loss is only 200 kWh, thus adjusting the three-phase load loss reduction potential.

    (2) the three-phase unbalanced load may cause serious consequencesto burn off the circuit, burned switch equipment:

    The imbalance of heavy phase current is too large (by 3 times), the overload multiple. The heat generated by the Q = 0.24I2Rt, the currentincreased to 3 times, then heat for 9 times, may cause the phaseconductor temperature rise, so that burning. And because the neutral conductor section in general should be a line section 50%, but in the choice, some are too small, plus the joint quality is not good, so that thewire resistance increases. Risk neutral line broken higher.

    Similarly in the power distribution panel switch, causing heavy loadphase burned, contactor heavy-duty phase burn out, so the damage and other serious consequences.