Setting calculation method for bus differential protection current loop line disconnection alarm fixed value

Abstract

The invention disclose a setting calculation method for a bus differential protection current loop line disconnection alarm fixed value, which solves the problem that the current loop line disconnection alarm signal of the transformer substation bus protection frequently happens due to the fact that the current transformer substation bus differential protection current loop line disconnection alarm fixed value is not reasonable. The setting calculation method comprises steps of establishing an imbalance current calculation model of a power transmission circuit according to the usage tower types, the lead phase sequence arrangement and the line length of all power transmission circuits which are connected to one bus of the transformer substation, calculating the positive sequence current, the negative sequence current and the zero sequence current of each loop of the power transmission circuit and the imbalance degree of the zero sequence current, performing actual measurement on the secondary zero sequence imbalance current of all power transmission lines after the transformer substation is in operation, and performing adjustment on the bus protection current loop line disconnection alarm fixed value according to whether the degree of imbalance of the zero sequence current is not greater than 5%. The setting calculation method overcomes the frequent actions of the bus protection current loop line disconnection alarm signal of the transformer station, and guarantees the safety operation of the power grid.

Description

technical field [0001] The invention relates to a method for setting the disconnection alarm setting value of the bus differential protection current loop of a substation, which is suitable for the setting calculation of the disconnection alarm setting value of the bus differential protection current loop connected to the multi-circuit transmission line of the substation bus, so that the substation bus differential It can reliably and accurately send out an alarm signal when the dynamic protection current loop is disconnected. Background technique [0002] With the development of the power grid, according to the different needs of the grid load, a large number of short-distance transmission lines erected without transposition appear in the power grid. The non-transposition erection (or incomplete transposition) of these short-distance transmission lines makes the three-phase current The aggravation of the unbalance has led to the frequent occurrence of disconnection alarms o...

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Problems solved by technology

[0003] The invention provides a setting calculation method for the disconnection alarm setting value of the differential protection current loop of the substation busbar, which solves the current problem caused by the unreasonable setting of the disconnection alarm setting value of the current loop differential protection current circuit of the substation busbar. The technical problem of frequent occurrence of loop disconnection alarm signals

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