Method for improving short-circuit current breaking capacity of transformer substation in line T connection mode

Abstract

The invention relates to a method for improving the short-circuit current breaking capacity of a transformer substation in a line T connection mode, which comprises the steps of firstly screening a target transformer substation with the short-circuit current of bus bars and branch lines meeting specific requirements from transformer substations of a power grid, then selecting an out-of-limit line and a servo line according to the structural layout of the transformer substation and the short-circuit current of each branch line, and T-connecting the out-of-limit line to the servo line. The design not only effectively improves the breaking capacity of the 220KV transformer substation to the short-circuit current, but also has good power supply reliability, economic and technical properties and adaptability.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a method for improving the short-circuit current breaking capacity of a transformer substation in a line T-connection mode. Background technique [0002] The short-circuit current seriously threatens the safe and stable operation of the power grid, and may easily cause equipment to heat up or even burn out. In order to ensure the safety of the power grid, it is necessary to isolate the fault in a small area through the circuit breaker. However, with the strengthening of grid interconnection, the rapid development of user load levels, and the gradual construction of grid power points, the problem of short-circuit current in some areas of the grid has become increasingly prominent. For some 220kV substations with a large number of outgoing lines and heavy loads, the short-circuit current of the 220kV bus has approached or even exceeded the rated breaking current level of t...

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Problems solved by technology

Chinese patent: application publication number CN102570431A, application publication date July 11, 2012 The invention patent discloses a method for limiting the short-circuit current of the power grid, which proposes a selection method and implementation plan for the pull-stop switch and the line for the 500kV short-circuit current of the substation , but there are obvious differences between the 220kV electrical main wiring mode of the substation and the 500kV electrical main wiring mode (the 500kV substation system adopts the 3 / 2 wiring mode, which has the condition of pulling the stop switch, while the 220kV system mainly uses double busbars with bypass or double busbars Segmented wiring method, pulling the stop switch will interrupt the load power consumption), the switch pull-stop solution for the 500kV main wiring method is not suitable for 220kV short-circuit current limit

This method is beneficial to reduce the short-circuit current of substations by using high-impedance transformers for unconstructed substations, but there are problems of large amount of engineering and high cost of transformation for existing substations.

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