On-line detection method of power grid fault based on least square estimation under finite pmu

Abstract

The invention discloses a method for detecting a grid fault online under the condition of a limited number of PMUs based on the least square method. According to the method, the area disperse policy decision structure is adopted, and the wide area protection information of a home substation and an adjacent substation is collected through RDS; when it is found that protective action is carried out on a circuit, the online detection process of the circuit and an adjacent circuit is started; the current and voltage measurement values of the related PMUs are collected, the current and voltage estimated values of each node are worked out, the current residual value of each circuit is obtained, two suspected circuits are obtained through ranking and searching; for the two suspected circuits, according to the topological link relation between the two suspected circuits, criteria of a fault of a single circuit and combination faults of two adjacent circuits and the like are established; according to three groups of PMU measurement values, the positions of three groups of fault points of each suspected circuit are worked out, fault criteria are established, and then a faulty element is judged and detected. By the adoption of the method, the three fault conditions including the fault of a single circuit, combination faults of adjacent circuits and dual faults of non-adjacent circuits can be distinguished, and the situation that an oversized communication load is added to the SDH of a wide area communication network is avoided.

Description

technical field [0001] The invention relates to the field of electric power system relay protection, in particular to an online fault detection method of a power grid based on least square method estimation under limited PMU. Background technique [0002] As the power system continues to develop and the grid structure becomes more and more complex, the configuration and adjustment of traditional backup protection based on local information becomes more and more difficult [1] . The development of the Synchronous Vector Measurement Unit (Phasor Measurement Unit, PMU) provides an important signal source for the research of wide-area backup protection. The PMU measures the bus voltage and the incoming and outgoing current vectors at the distribution point in real time, and marks them with time [2] . The remote transmission of PMU quantity measurement relies on the Synchronous Digital Hierarchy (SDH) of the wide-area communication network widely used in my country at present, a...

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Problems solved by technology

[0004] However, the existing literature has not studied the multiple faults of adjacent lines under the limited PMU layout, and has not given the corresponding online detection method for grid fault components.

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