Transformer backup protection method in six-phase power transmission system
A backup protection and power transmission system technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of not meeting the sensitivity requirements, sensitivity reduction, etc., and achieve the effect of simple and clear discrimination principle, overcoming sensitivity reduction, and easy implementation
Active Publication Date: 2014-06-18
江苏燎源变压器有限公司
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This means: if the transformer in the six-phase system still adopts the same traditional backup protection as the three-phase transformer, its sensitivity as the backup of the transformer itself and the remote backup of the six-phase transmission line will be greatly reduced, and it is very likely that it will not meet the sensitivity requirements
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[0029] The present invention will be described below in conjunction with the drawings and embodiments.
[0030] The six-sequence component conversion matrix is [6]
[0031] M = 1 6 1 1 1 1 1 1 1 1 a 2 a 2 a a 1 1 a a a 2 a 2 1 - 1 1 - 1 1 - 1 1 - 1 a 2 - a 2 a - a 1 - 1 a - a a 2 - a 2 - - - ( 1 )
[0032] Where: a=e j120° . Using M, the six phase voltages and six phase currents at any point in the same pole double circuit system (two three-phase) or six-phase transmission system can be converted into six sequence voltage components And six sequence current components Among them, the subscript T0 is the same zero sequence component; the subscripts T1, T2, F0, F1 and F2 are the same positive sequence component, the same negative sequence compo...
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The invention relates to a transformer backup protection method in a six-phase power transmission system. The method comprises the steps that two sets of three-phase currents on the side of a transformer three-phase system are collected, and the amplitude of same positive sequence currents, the amplitude of same negative sequence currents and the amplitude of reverse positive sequence currents are respectively calculated through a six-sequence component method (please see the specification for the expression); the same positive sequence currents are used for judging a six-phase short circuit, when the amplitude of the same positive sequence currents is larger than a setting value IT1.op, protection action is performed, the setting value is set according to the maximum same positive sequence current, namely a load current IN during normal operation; the same negative sequence currents and the reverse positive sequence currents are used for judging all the interphase short circuits except the six-phase short circuit, when the amplitude of the same negative sequence currents or the amplitude of the reverse positive sequence currents is larger than a setting value IT2.op or IF1.op, protective action is performed, the setting value IT2.op and the setting value IF1.op are set according to the maximum same negative sequence unbalanced current and the maximum reverse positive sequence unbalanced current during normal operation, and three current protection OR gates are used for outputting. The transformer backup protection method in the six-phase power transmission system has the advantages of being higher in protection sensitivity and easy to implement.
Description
Technical field [0001] The invention relates to a new transmission mode of the electric power system-the field of six-phase power transmission and relay protection, in particular to a transformer backup protection method applied to the six-phase power transmission system. Background technique [0002] Six-phase power transmission has huge economic and environmental benefits. It can not only increase the natural power of the line transmission, reduce the footprint of the line corridor, but also suppress the occurrence of corona and reduce radio interference. It is an important development direction for UHV power transmission [1]. Attached figure 1 It is a typical six-phase transmission system, consisting of four transformers and six-phase transmission lines. The parallel three-phase system is transformed into a six-phase system through two transformers, and the six-phase system is transformed into a parallel three-phase system through two transformers at the other end. Phase syste...
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IPC IPC(8): H02H7/04
Inventor 张艳霞王海江
Owner 江苏燎源变压器有限公司