Self-adaptive distance protection method for double-circuit line of intelligent substation

Abstract

The invention discloses a self-adaptive distance protection method for a double-circuit line of an intelligent substation, belonging to the technical field of the power system automation. The method comprises the following steps of: 1) acquiring electrical quantity information; 2) performing the self-adaptation of a distance protection fixed value under special operating conditions; and 3) performing the self-adaptation of an impedance relay based on fault type recognition. The self-adaptive distance protection method is capable of effectively overcoming the influence of the zero-sequence mutual induction of the double-circuit line on distance protection, and simultaneously solving the problem of the sensitivity of the distance protection in case of a cross-line fault. Furthermore, the method is applied to field practice without increasing the fixed value or increasing secondary circuit connections and communication loads, and thereby has high practicable value.

Description

technical field [0001] The invention relates to an adaptive distance protection method suitable for a double-circuit line of an intelligent substation, and belongs to the technical field of power system automation. Background technique [0002] Compared with single-circuit lines on the same pole, double-circuit lines on the same pole increase the line transmission capacity on the outlet corridor of the unit, and the investment is less than that of building two single-circuit transmission lines. Therefore, more and more domestic UHV, EHV and HV lines use double-circuit lines on the same pole for power transmission. [0003] In traditional substations, considering the complexity of the wiring and the reliability of the protection, the two circuits of the double-circuit line on the same pole are independently configured for protection. Any one of the protections only collects the electrical and switching information of the corresponding line, and does not collect phase informat...

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Problems solved by technology

[0004] However, the double-circuit line on the same pole is prone to complex faults such as cross-line due to the short distance between the two circuits. Even a single-circuit line fault may cause the relay protection of the faulty line or the sound line due to the mutual coupling of adjacent lines. incorrect action

Especially for distance protection, the principles of current schemes are based on single-circuit lines, and there is no major improvement when applied to double-circuit lines. When a single-phase fault occurs outside the area, double-circuit lines may exceed the action due to the influence of zero-sequence mutual inductance , when a cross-line fault occurs, it may have no sensitivity and refuse to move

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