A transient fault ride-through control method of a high-voltage frequency converter and a system thereof

Abstract

The invention discloses a transient fault ride-through control method of a high-voltage frequency converter. The method comprises the following steps: an output current value of the frequency converter is sampled in real time; if the output current value is greater than a set protection value, the operating frequency and an output voltage of the frequency converter are set to the lowest value, so that the output voltage of the frequency converter is rapidly reduced, and a motor stator current is also rapidly reduced so to prevent the stator current from rising to a shutdown protection value and causing a halt, thereby realizing fault ride-through; then, through automatic flexible recovery, the output voltage and frequency of the motor rise, and the pressure of a hydraulic pump of a well-wall corer gets recovered; and a drill bit can continue drilling to realize the fault ride-through. The invention also provides the system of realizing the above method. According to the invention, when the current of a sticking stator surges, the current is reduced to be in a safety scope to avoid occurrence of protective shutdown, and flexible automatic recovery can be realized so that a continuous power can be provided for timely drill withdrawing and subsequent drilling when sticking of drilling of the well-wall corer occurs.

Description

Technical field [0001] The invention belongs to the field of power electronic equipment, and relates to a method and system for controlling a high-voltage frequency converter for supplying power to a drilling-type borehole corer. During the process, when the drill bit gets stuck (the mechanical load of the motor increases sharply), it prevents the inverter from shutting down due to excessive output current, and realizes the automatic and flexible recovery of the inverter so that the motor quickly restores the power supply to the core remover, thereby crossing the stuck drill Failure control method and system. Background technique [0002] In the field of borehole wall coring, when the borehole corer and its drive motor are used for coring operations at several thousand meters deep underground rock formations, the high-voltage frequency converter is located at the wellhead, and the frequency converter is fed through a long cable. Motor power supply. The frequency converter input...

AI Technical Summary

Problems solved by technology

Although this treatment method can prevent equipment damage, it cannot be applied to the frequency converter of the borehole corer

Because the drill bit of the borehole wall corer is stuck, once the frequency converter stops, the drive motor cannot work, and the entire corer loses power. If the tool slides under the impact of downhole mud circulation, the drill bit embedded in the rock will be completely stuck. At this time, even if the motor is restarted, the drill bit cannot be withdrawn from the rock, and it is even more difficult to continue drilling; , which in turn will cause the corer to stay in the same rock formation for too long, the corer will be stuck by the mud in the well, and the corer will not be able to move or even be pulled out of the deep well, causing serious production accidents. Inverter shutdown protection will cause serious consequences

[0004] In order to avoid the above-mentioned accidents, when the drill bit is stuck, the operator of the sidewall coring device often has to keep an eye on the display data on the panel of the coring control system, respond quickly when the data is abnormal, and immediately press the button to return the drill , to avoid damage to the coring instrument due to high current, and to avoid the loss of power supply to the motor caused by the shutdown of the frequency converter, the energy must be highly concentrated. Slow operation will result in damage to the high-current corer or the corer cannot return to drill and continue when the frequency converter is stopped. drill into

During a coring process that lasts for tens of hours, there are a lot of stuck pipes, which puts a huge burden on the coring operators

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