Current differential protection is the main protection of transmission lines which include\nmulti-circuit lines on the same tower, and whose sensitivity and reliability of differential protection\nis mainly affected by the distributed capacitive current. For the four-circuit line on the same tower,\ndue to the influence of coupling between the loop road, the distributed capacitance current increases\nsignificantly when compared with ordinary lines, affecting the sensitivity of the current differential\nprotection, especially for different voltage levels throughout the four-circuit lines on the same tower.\nThe relationship of the electrostatic coupling between the circuits is more complex, and increases\nthe difficulty of the compensating the distributed capacitance current. This paper is based on the\nelectrostatic coupling principle of four-circuit lines on the same tower, establishes the distributed\nparameter model of four-circuit transmission lines on the same tower, and discusses the effect of\ncircuit operation mode on the compensation of capacitance current differential protection when\ndifferent faults occur on the complex four-circuit transmission lines on the same tower. A new\ncompensation scheme suitable for capacitive current compensation is proposed. Simulation results\nshow that this capacitive current compensation scheme can effectively improve the performance of\ncurrent differential protection.
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