A control and protection processing method for direct current engineering without grounding electrodes

Abstract

A control and protection processing method for the operation of a DC project without a grounding electrode. The DC station control system, the DC pole control system and the DC protection system cooperate to perform control and protection; the DC station control system sets the chain condition of the grounding switch in the station to be forcibly satisfied; The station control system sets the judgment condition of the connection state of the ground electrode to cancel the association with the sub-state of the grounding switch in the rectification station, and the condition for judging the status of the grounding switch in the rectification station is compulsorily met in the inverter station; DC pole control The system is equipped with a bipolar synchronous unlocking / blocking unit, a bipolar current following unit and a bipolar joint jump unit. The invention solves the problem of maintaining bipolar balanced operation when the DC project uses the grounding grid in the station as the grounding pole, is scientific and effective, and can meet the requirements of engineering applications.

Description

technical field [0001] The invention relates to the technical field of electric power systems, in particular to a control and protection processing method for direct current projects operating in a non-grounded electrode mode. Background technique [0002] The grounding electrode is an important part of the conventional DC engineering. It not only plays the role of clamping the DC neutral point potential, but also provides the ground as the current return path for the DC single-pole ground return method and the double-pole grounding method. Therefore, if There is no grounding pole, although the DC neutral point potential can be clamped by the grounding network in the station, the earth cannot be used as the current return path. Therefore, if a unipolar block occurs during DC bipolar operation, the DC current will not have a transfer circuit and cause bipolar atresia. DC will usually not be able to run bipolar, but can only run in the form of unipolar metal loops, which will...

AI Technical Summary

Problems solved by technology

However, under the existing technical conditions, when the grounding grid is used as the grounding point on the rectifier side, it cannot be used in the single-pole operation mode because the design principle of the grounding grid is different from that of the grounding electrode.

In addition, in order to reduce the grounding current and its duration as much as possible, the unlocking of the two poles and emergency shutdown must be completed in the shortest possible time; at the same time, considering the electrical corrosion of the grounding current to the grounding grid, a cathode must be used The protection law protects the grounding grid, and the existing technologies are currently unable to meet the above requirements

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