Directional current protection method and device
A current protection and directional technology, which is applied to emergency protection circuit devices, circuit devices, emergency protection devices with automatic disconnection, etc., can solve the problems of low cost and achieve low cost, high reliability and wide application range Effect
Active Publication Date: 2015-04-29
CHANGSHU SWITCHGEAR MFG CO LTD (FORMER CHANGSHU SWITCHGEAR PLANT)
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Problems solved by technology
[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the existing directional current protection technology, and provide a directional current protection method and device, which can still achieve reliable directional protection when a near-field fault occurs, and does not require additional Hardware, low cost to implement
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[0026] The technical scheme of the present invention is described in detail below in conjunction with accompanying drawing:
[0027] Aiming at the problem that it is difficult for the existing directional protection equipment to effectively determine the fault direction when a fault occurs in the near area, thereby affecting the directional protection, the idea of the present invention is based on the effective value of the phase voltage of the current cycle and the effective value of the phase voltage of the previous cycle. Judging whether the current fault is a near-area fault based on the changes in time, if it is judged that it is not a near-area fault, then according to the existing method to judge the fault direction according to the current and voltage of the current cycle and take corresponding protection actions, if it is judged that it is a near-area fault If there is a fault, the voltage of the current cycle is not used, but the fault direction is judged according ...
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The invention discloses a directional current protection method, and belongs to the technical field of smart power grids. According to the change condition of a phase voltage effective value of a current cyclic wave and a phase voltage effective value of a previous cyclic wave, whether a current fault is a short-line fault is judged; if the current fault is not the short-line fault, the fault direction is judged according to current and voltage of the current cyclic wave with a conventional method, and corresponding protection actions are adopted; if the current fault is the short-line fault, voltage of the current cyclic wave is not adopted, the fault direction is judged according to voltage of the previous cyclic wave and current of the current cyclic wave, and corresponding protection actions are adopted. The invention further discloses a directional current protection device. Compared with the prior art, the method and the device have the advantages that reliable directional protection can still be realized when the short-line fault occurs, additional hardware is not required to be added, and the cost is low.
Description
technical field [0001] The invention relates to a directional current protection method and device, belonging to the technical field of smart grids. Background technique [0002] In recent years, with the development of smart grids, low-voltage circuit breakers have been increasingly used in new energy and distributed power applications. Distributed power units can both feed current to the grid and consume electricity from the grid. This means that in this case, the direction of the fault can change with time, and when a current fault occurs, determining the direction of the fault current becomes a prerequisite for the corresponding protection of the circuit breaker. The traditional method of judging the fault direction is through the power direction relay, which is also the method used most of the time. The power directional relay usually includes a directional element and an action element: the directional element judges the fault direction by using phase comparison or a...
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IPC IPC(8): H02H3/00H02H3/093
Inventor 殷建强奚慎云任灵
Owner CHANGSHU SWITCHGEAR MFG CO LTD (FORMER CHANGSHU SWITCHGEAR PLANT)