Control method for improving reliability of impressed current cathodic protection of offshore wind power pile foundation

Abstract

The invention discloses a control method and system for improving reliability of impressed current cathodic protection of an offshore wind power pile foundation. The control method and system for improving the reliability of impressed current cathodic protection of the offshore wind power pile foundation are applied to an impressed current cathodic protection system. In a normal protection state, the system outputs in a constant potential operation mode, when the system encounters an extreme working condition or a reference electrode controlled by the system breaks down, the system is automatically switched to a constant current mode to set upper and lower limit values of output current for output, therefore, over-protection or under-protection, of a protected structure, caused by over-limit output of the impressed current cathodic protection system under the extreme abnormal working condition is prevented, and the operation reliability of the impressed current cathodic protection system is improved; and meanwhile, output current of a numerical control high-frequency switching power supply can be controlled in real time through technologies such as closed-loop PID increment adjustment and PWM modulation, when output protection current exceeds a protection current output limit interval, the constant potential control mode is automatically switched into a constant current control mode, and constant current output is conducted according to the set upper and lower limits of the output current.

Description

technical field [0001] The invention relates to the technical field of cathodic protection and anticorrosion, in particular to a control method for improving the reliability of cathodic protection of applied current for offshore wind power pile foundations. Background technique [0002] Offshore wind power, as the main clean energy developed by the country in recent years, has a large installed capacity of a single unit, a high number of effective utilization hours, and does not occupy land resources. It is close to the national coastal power load center and has broad application prospects. The underwater foundation of offshore wind power has various structural forms, such as single pile type, group pile type, floating type, negative pressure barrel type, jacket type, etc., which have been in the harsh marine corrosion environment of the open sea for a long time, and cathodic protection and anticorrosion are usually adopted Coating for joint protection. [0003] As an effec...

AI Technical Summary

Problems solved by technology

However, in complex marine working conditions, the reliability and stability of the reference electrode used for current output control is very important. This is because in actual operation, all adjustments are based on this parameter. If there is a problem with it, If there is a deviation in the basic adjustment basis of the output current, there may be a greater safety hazard in the constant potential mode operation.

That is, if there is an abnormality of the reference electrode (water seepage and corrosion of the electrode, external damage including ice floes, etc., self-dissolution, virtual connection of the end point of the measurement circuit, etc.), drastic changes in external working conditions (adhesion by marine organisms, coverage by dirt, return of sea mud, etc.) silt) and other situations, often lead to short-term sudden change or long-term deviation of the measured potential, making the output current of the impressed current cathodic protection system extremely small (no current output, under-protection) or extremely large (output current exceeds the design limit, over-protection), directly Affects the protective effect of impressed current cathodic protection system on structures

[0005] For example, CN202688452U invented an impressed current cathodic protection system suitable for offshore wind power pile foundations based on the commonly used auxiliary anode form for ship outer wall protection. The system only uses the difference between the measured protection potential and the set protection potential as a judgment basis to adjust the current The output, control logic and algorithm are relatively simple and do not consider the influence of extreme working conditions of offshore wind power; another example, CN103726057A introduces an impressed current cathodic protection system for the triangular pile foundation structure of offshore wind power, and the control system part of the patent has constant potential control and constant current control, which are also the operating modes of potentiostats used in impressed current cathodic protection systems in various industries at present, without considering the particularity of unattended offshore wind power and offshore extreme sea conditions

[0006] Therefore, it can be seen that the potentiostats of the above-mentioned patents are common output control methods, and the control logic and algorithm of the potentiostat have not been specifically designed and developed for the extreme working conditions of offshore wind power. When the main control reference electrode or When the measurement circuit is faulty, it is prone to long-term over-protection or under-protection

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