Six-sequence component-based double circuit lines on same pole phase difference protection method

Abstract

The invention belongs to the field of relay protection of a power system, and relates to a six-sequence component-based double circuit lines on same pole phase difference protection method. The method comprises the following steps of: (1) acquiring six currents on each side of double-circuit lines by using current transformers at the protective installation positions on m and n sides of a circuit; (2) converting the six currents on each side of the double-circuit lines into six sequence current components by six-sequence transformation; (3) respectively subtracting corresponding sequence component a week before a fault from the same positive sequence components on the two sides to obtain respective same positive sequence fault components; (4) constructing composite currents by using the same positive sequence fault components, reverse positive sequence components and the same negative sequence components of the six sequence current components, and respectively solving the phase angles of the composite currents on the two sides; and (5) setting a phase difference protection action angle as Phi OP, determining that an internal fault exists if the absolute value of the difference between the phase angles of composite currents on the two sides of the circuit is smaller than the action angle, and otherwise, judging to be an external fault. By the method, a fault, particularly a cross-line fault, can be judged very well; and the method is easy to implement.

Description

technical field [0001] The invention relates to the field of relay protection of electric power systems, in particular to a new method for phase difference protection of double circuit lines on the same pole based on six-sequence components. Background technique [0002] On double-circuit lines on the same pole with a voltage level of 220kV and above, the protection configuration generally uses the phase-separated current difference action as the first main protection, the direction or distance longitudinal connection as the second main protection, and the three-stage distance protection as the backup protection [1] . However, the phase-separated current differential protection of the double-circuit line on the same pole needs to compare the current amplitudes at both ends of the six lines, which occupies a large number of channels, making it more likely that the reliability will be reduced due to channel failure, and the price expensive. As the second main protection, the...

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Problems solved by technology

When the double-circuit line on the same pole is regarded as two three-phase transmission lines, this principle can be directly used on the double-circuit line on the same pole as the second main protection, but it is difficult to correctly determine the cross-line fault of the double-circuit line on the same pole [2、3]

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