Line-drop compensation on single-phase regulators

WHEN SINGLE-PHASE voltage regulators are connected in delta or in open-delta on 3-phase systems, the regulator is excited by the line-to-line voltage, but it transmits line current. For this reason, a line-drop compensator in the control circuit of a regulator so connected has a 30-degree phase difference between its voltage and current supplies. The proper operation of the regulator depends upon the line-drop compensator's duplicating, in the control circuit, the effect of resistance and reactance voltage drops in the line. To permit this, the effect of the 30-degree phase displacement between voltage and current must be counterbalanced.