Effects of high voltage line

    (1) increase the high voltage line loss:

    Low voltage three-phase load balance, 6 ~ 10K high voltage side Vbalance, a high voltage line the current in each phase is I, the power loss is: Δ P1 = 3I2 Low voltage three-phase unbalanced load will be reflected in the high side,the maximum unbalance, voltage corresponding to 1.5I, the other two are 0.75 I, power loss: The Δ P2 = 2 (0.75I) 2R + (1.5I) 2R = 3.375I2R =1.125 (3I2R) The high-pressure line energy loss increased by 12.5%.

    (2) increase the high line tripping, reduce the number of switchingequipment service life:

     We know that the high voltage line overcurrent fault accounted for a considerable proportion, the reason is that the current is too large. Low voltage three-phase load imbalance may cause pressure a phase currentis too large, resulting in high voltage line overcurrent trip blackout, caused widespread blackouts, and substation switching equipment will reduce the service life of frequent trip.