A method for diagnosing and controlling the out-of-control signal of a hydraulic turbine governor

Abstract

The invention relates to hydraulic turbine governor out-of-control signal diagnosis and control methods. The diagnosis method is mainly based on electrical feedback signals acquired by a measuring unit of a hydraulic turbine governor; when the governor receives a command for opening or closing a guide vane, a difference value exists between control output, namely a target value that the guide vane needs to reach, and actual guide vane opening, and the difference value is higher than a set dead zone value; on normal conditions, a main distributing valve of the governor is controlled by PID (proportion integration differentiation) computation of a PLC (programmable logic controller) to be opened towards a target direction by a certain opening, and the guide vane is controlled to move towards the target direction; then periodical scanning is performed through a PLC program to read whether the opening of the guide vane moves towards the target direction or not and judge whether a movement speed meets the requirement for governing computation on-off time or not, and if a change value, read within a certain delay time, of the guide vane opening does not reach a change rate towards the target direction, the governor is judged to be out of control, and safety of a generator set is protected.

Description

technical field [0001] The invention relates to an out-of-control signal diagnosis and control method of a water turbine governor system, which is mainly used in a hydraulic control system of a water turbine governor, and can also be widely used in control processes in other related automation fields. Background technique [0002] At present, the out-of-control signal of the governor is expressed by the card-sending contact of the main pressure distribution valve, and this signal is led to a position contact switch installed on the installation base of the main pressure distribution valve. When the main pressure distribution valve of the governor moves towards the closing direction, the contact switch closes; when the main pressure distribution valve returns to the center or moves towards the opening direction, the contact switch opens, and this node is sent to the monitoring system and combined with the speed exceeding 115% signal It will cause an emergency shutdown to prot...

AI Technical Summary

Problems solved by technology

[0003] (1) The card-issuing contact of the main pressure distribution valve cannot accurately reflect the out-of-control state of the governor, but can only show that the main pressure distribution valve is not moving in the closing direction; modern governors are all adjusted by PID through PLC, and the scan cycle reaches milliseconds. For example, when the speed rises to the peak and starts to drop, although the frequency still exceeds the rated frequency at this time, the frequency drops rapidly. After the PID calculation, the guide vane may need to be opened, and this node will act at this time, causing an emergency shutdown malfunction;

[0004] (2) The card-issuing node of the main pressure distribution valve cannot reflect the action rate of the governor control guide vane. If the main pressure distribution valve can operate, but the action is not flexible, the original card-issuing contact of the main pressure distribution valve will not alarm. At this time, the main pressure distribution valve If the valve action is not in place, the oil port cannot be fully opened, which will slow down the action speed of the guide vane. At this time, the closing time of the guide vane will greatly exceed the maintenance calculation time, which will cause serious accidents;

[0005] (3) The contacts of the original travel switch are prone to erroneous signal transmission due to jitter or refusal to move due to contact aging, and the reliability is not high;

[0006] (4) Due to the problem of the structure and position of the contact and the valve body, it is extremely difficult to adjust properly;

[0007] (5) In the original mode, relevant tests and tests cannot be carried out by simulating the out-of-control state of the governor