Method for suppressing neutral point DC magnetic biasing by single grounding network and device thereof
A transformer neutral point, separate grounding technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of transformer neutral point potential rise, inability to fully adapt to actual needs, implementation restrictions, etc., to achieve safety and reliability Performance improvement, no operation and maintenance costs, and less engineering
Active Publication Date: 2012-10-03
SHANGHAI MUNICIPAL ELECTRIC POWER CO +1
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Problems solved by technology
However, some problems should be paid attention to in the actual design: when the network structure changes, the resistance value should be recalculated and the resistance should be replaced; when the system fails, the neutral point potential of the transformer will rise and overvoltage will occur, and preventive measures should be taken, etc.
[0015] To sum up, although the current three schemes are feasible in principle, they will always encounter various problems in actual operation, and there are many limitations in their implementation, which cannot fully meet the actual needs
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[0042] The present invention will be further described below in conjunction with the accompanying drawings.
[0043] figure 1Among them, this technical solution includes the neutral point of the substation main grounding network 2 and the transformer 1, and its invention point is to set a transformer neutral point dedicated by at least two sets of vertical grounding poles outside the existing substation main grounding network. Grounding network 3, which isolates the grounding channel of the transformer neutral point from the grounding channel of other primary equipment in the substation; the special grounding network for the neutral point of the transformer is electrically connected with the neutral point of the transformer; the special grounding network for the neutral point of the transformer and the substation An isolation device 4 is arranged between the main grounding grids.
[0044] The grounding resistance of the special grounding network for the neutral point of the t...
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The invention relates to a method which adopts a single grounding grid to inhibit neutral point direct-current magnetic biasing of a transformer, belonging to the field of the power transformation and distribution. A transformer neutral point special grounding grid which comprises at least two groups of vertical grounding electrodes is additionally arranged outside a transformer main grounding grid, a grounding channel of a transformer neutral point is separated from grounding channels of other primary devices of a transformer, the transformer neutral point special grounding grid is electrically connected with the transformer neutral point, and an isolating device is arranged between the transformer neutral point special grounding grid and the transformer main grounding grid; when the faults happen, the isolating device is instantly conducted, therefore, the two groups of grounding grids operate in parallel. The invention also provides a device which adopts the method. The special grounding grids are completely irrelevant to a circuit topological structure of a power grid, thereby being not influenced by the change of the power grid structure, and the safety reliability is improved; the design is simple, the cost is low, the engineering quantities are less, and the operation and maintenance expenses are not needed. The invention can be widely applied in the fields of the power transmission, the power transformation and the power distribution of an electric power system.
Description
technical field [0001] The invention belongs to the field of electric power generation, transformation or distribution, and in particular relates to an emergency protection circuit device for suppressing the DC bias phenomenon at the neutral point of a transformer. Background technique [0002] With the development of our country's economy and society, high voltage direct current (HVDC, High Voltage Direct Current) power transmission system is getting more and more widely used in our country. In order to achieve long-distance and large-capacity power transmission, more ultra-high voltage and even ultra-high voltage DC projects will be built and put into operation. [0003] When the DC transmission system operates in a single-pole ground loop mode, the huge DC current forms a loop with the ground. Part of the DC current flows through the neutral point grounded power transformer and other equipment, forming a loop in the AC system. Due to the DC bias effect, the transformer c...
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IPC IPC(8): H02H7/04H02H7/28
Inventor 付坚吴忠明冯远程
Owner SHANGHAI MUNICIPAL ELECTRIC POWER CO