Optional voltage type drainage circuit structure

Abstract

The invention provides an optional voltage type drainage circuit structure which comprises a drainage circuit, a control circuit, a detection circuit and a set switch, wherein the detection circuit is connected with a pipeline testing terminal and a reference electrode of a metal pipeline protection circuit structure, and is sequentially connected with the control circuit and the drainage circuit; the control circuit is connected with the set switch; the drainage circuit is divided into a main circuit and a spare circuit, and is connected with a magnesium anode of the metal pipeline protection circuit structure. The optional voltage type drainage circuit structure has the effects that the function of intelligent 'on-demand drainage' can be realized by the circuits; the whole drainage system does not have drainage blind area voltage, so that the consumption of the magnesium anode is greatly reduced, and the operating cost is saved. The working state of the main circuit is detected by the control circuit regularly every 2h-4h; if the main circuit is abnormal due to damage, the main circuit is immediately switched to the spare circuit, and the negative potential of the magnesium anode is isolated by the spare circuit and can not be completely applied onto a pipeline, so that the phenomena that the metal pipeline has hydrogen evolution reaction, an insulating layer of the pipeline falls off, and the like can be avoided, and the pipeline drainage operation is safe and reliable.

Description

technical field [0001] The invention relates to an optional voltage type drainage circuit structure for protecting oil and gas metal pipelines along electrified railways from being corroded by stray currents. Background technique [0002] At present, the protection of oil and gas metal pipelines along the electrified railway mostly adopts the forced drainage method, that is, no matter what the potential of the pipeline is, whether drainage is required, the drainage device directly connects the pipeline and the magnesium anode through a diode to perform forced drainage. This method is simple in structure, but its intelligence is poor, and it is difficult to monitor and maintain. The main disadvantages are as follows: [0003] 1. Since the protection voltage of the pipeline is not set, and it is impossible to distinguish whether there is induction interference on the pipeline, direct drainage is adopted, so the buried magnesium anode will also cause consumption when the draina...

AI Technical Summary

Problems solved by technology

This method is simple in structure, but its intelligence is poor, and it is difficult to monitor and maintain. The main disadvantages are as follows:

[0003] 1. Since the protection voltage of the pipeline is not set, and it is impossible to distinguish whether there is induction interference on the pipeline, direct drainage is adopted, so the buried magnesium anode will also cause consumption when the drainage is not actually required, thereby reducing the service life of the anode and increasing operating costs;

[0004] 2. Due to the influence of parameters such as the working voltage of the diode, when the negative potential of the magnesium anode is insufficient after peroxidation, or when the ground potential of the tube is lower than the normal working voltage of the diode, the diode cannot conduct forward smoothly, and there is a blind area for drainage;

[0005] 3. When the diode is damaged by reverse breakdown, the negative potential of the magnesium anode will be completely applied to the pipeline. At this time, the pipeline will be overprotected, and the hydrogen evolution reaction will occur in the pipeline, causing the insulation layer of the pipeline to fall off, which will accelerate the pipeline. oxidation corrosion

However, the current drainage structure is based on the principle of forced drainage, which cannot meet the new requirements.

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