RU2762269C1 - System and method for monitoring turbine line elements - Google Patents

Abstract

FIELD: endoscopic systems.

SUBSTANCE: invention relates to endoscopic systems that are used to inspect steam turbines during maintenance and repair and when testing turbines. The monitoring system consists of gateways to provide access without opening the turbine flow paths, video probes, a unit for creating a light flux of various directions, a server that provides reception, storage and processing of primary data, sounding data of the turbine flow path elements, a synchronization sensor, lines and communication units. The video probe contains a multi-channel video head, LED illumination and structured illumination. The synchronization sensor consists of a zero-position sensor and a rotation angle sensor. The method for monitoring the elements of the turbine flow path includes placing video probes in the turbine flow path, controlling the video probes to receive frames, transmitting and processing the received data on the server.

EFFECT: improving the accuracy of diagnostics and reducing its terms.

2 cl

Description

The invention relates to endoscopic systems that are used to inspect steam turbines during maintenance and repair and when testing turbines.

An endoscopic system for examining gas turbines (RU 2610973, publ. 17.02.2017, bulletin No. 5) is known from the prior art, containing an endoscope and a data processing device, and the endoscope contains an image recording device and is configured to transmit image recordings from an image recording device from inside the gas turbine to the data processing device, configured to position and orient in the gas turbine an endoscope with an image recording device introduced into the gas turbine in a certain way. During use, the endoscopic head is inserted into a limited and hard-to-reach space and visually guided to the frequency monitoring object using images captured by a video camera under illumination from a lighting device. The disadvantage of this technical solution is the insufficiency of the field of view of the endoscopic head, which makes it necessary to reposition the endoscope during monitoring to fully cover the surfaces of the controlled parts.

The closest to the claimed technical solution is a device for monitoring the state inside the turbine assemblies and parts of steam turbines (RU 2624380, publ. 03.07.2017, bul. No. 19), which consists of locks to provide access without opening the flow paths of the steam turbine during operation, both at barring and at a complete stop of turbines, video probes entering the endoscopic unit with a recorder, a unit for creating a luminous flux of various directions, and signals from the video probes controlled from the control panel enter through the switching unit, in which digital signals are amplified central computer unit for processing and accumulating data, into a memory device, while all actions to determine the location of the endoscopic unit in relation to receiving data from video probes are consistent with a calibrated sync sensor located permanently on the shaft of a steam turbine, which is fed back through the processing center controls the location of the video probes relative to the scapula and flow path elements. The main disadvantage of this technical solution is the lack of automation of measurements of defects, leading to a decrease in the measurement accuracy due to the human factor, which entails an increase in the likelihood of making incorrect decisions about the need to replace or repair turbine parts.

The task to be solved by the claimed invention is the development of a system that provides the possibility of automatic monitoring during operation of all stages of flow paths, in-turbine assemblies and parts, including the blade apparatus.

This problem is solved by the claimed group of inventions. The first invention discloses a system for monitoring the state inside turbine units and turbine parts, which consists of locks to provide access without opening the turbine flow parts during operation, both at barring and at complete shutdown of turbines, video probes included in the endoscopic unit with a recorder, unit creating a luminous flux of various directions, a server that provides reception, storage and processing of primary data, sensing data of the turbine flow path elements, a synchronization sensor, communication lines and units, a video probe contains a multichannel video head, which is an optoelectronic device consisting of several small-sized video cameras, controlled LED illumination and structured illumination, and the synchronization sensor consists of a zero position sensor, which is an optical reflective sensor with a reflective mark and rigidly mounted on the shaft, and a rotation angle sensor including a code strip ntu, wrapped around the turbine rotor and rigidly fixed on it, and a reader, while the tape is encoded and read by an optical-mechanical or magnetic method, while the code for each angular position is unique. The second invention discloses a method for monitoring elements of the turbine flow path, which includes placing video probes in the turbine flow path, controlling video probes to receive frames, transmitting and processing the received data on the server, for analyzing the received information, the server contains the data of passports of the initial data of in-turbine units and parts, parameters of the blade apparatus by stages, their limiting criteria for wear and damage, determination of the position of the endoscopic unit is carried out in relation to receiving data from the video probes, coordinating with a calibrated synchronization sensor located stationary on the turbine shaft, and the position of the video probes relative to the blade apparatus is monitored by feedback through the data processing unit and elements of the flow path, data processing includes determining the number of the blade in the frame according to the readings of the synchronization sensor at the time of shooting, multi-angle complexing of images obtained in the process All one shooting operation using different channels of a multichannel video endoscope, measuring the deviation of the blade shape from the ideal by means of morphological image processing, taking into account the scale factor obtained using structured illumination, while preliminarily before measurements, the correspondence between the angle of rotation of the shaft and the position of the blade in the video head frame is determined , including the initial calibration, containing the introduction of the video endoscope into the turbine to the required depth and at the angle optimal for shooting the blades when the turbine rotates with a barring device at a speed of no more than 3 rpm, recording the video stream for a full revolution, with each received frame of the video stream being marked synchronization data, followed by selection of images in the most suitable position and saving them for further use to obtain synchronized images of specific blades.

The technical result is to increase the accuracy of diagnostics, reduce the period of equipment diagnostics to 1-2 weeks without losing the quality of diagnostics, which increases the reliability of the turbine, increases its service life and the overhaul period.

The declared system for monitoring the elements of the flow path on a closed high-pressure cylinder (HPC) and a low-pressure cylinder (LPC) of steam turbines is designed to determine the state of the rotor blades, damper links and fasteners without opening the LPC and HPC during scheduled preventive maintenance (PPR) and overhaul (CRR) of the power unit using a barring device, improving the efficiency and quality of management decisions.

The main purpose of the declared system is to automate information and analytical activities when planning the timing and scope of repairs of the HPC and LPG for detected defects in the flow path without opening the LPP and HPC and eliminating the prerequisites for emergencies in the flow path of the HPC and LPG of a steam turbine.

Diagnostics of the state of elements inside turbine assemblies and parts of flow paths is carried out on a closed turbine, both at barring and at full stop. As a result, the reliability of the flow paths of steam turbines is increased, their service life is extended, the overhaul period and the planning of the required amount of repair work are planned, followed by the forecast of the residual life of the flow path elements based on their actual state.

Endoscopy is performed according to the inspection map with video and photographic recording of in-turbine units and parts, for the subsequent accumulation of information and comparative analysis. These functions of the system can be performed both at complete shutdown of the steam turbine and at barring. Steam turbine flow parts are equipped with special inlet fittings with plugs, which are removed during the period of indication of damage and wear inside the turbine assemblies and parts. Each channel is designed in such a way that allows the installation of endoscopy equipment - flexible, semi-rigid, rigid probes in the cross-section of the steam turbine stages and endoscopy of all available in-turbine units and parts of steam turbines both at full stop and at barring.

The monitoring system includes channels (sluices) to provide access without opening the turbine flow paths during operation, both at barring and at full stop of the turbines, video probes included in the endoscopic unit with a recorder, a unit for creating a light flux of various directions, a calibrated synchronization sensor, a server with matching and expansion units, which also provides collection and processing of information, communication lines and units.

The server provides reception, storage and processing of primary data, data of sounding of the elements of the flow paths of the LPC and HPC of a steam turbine. To obtain data that objectively assess the state of in-turbine units and parts of a steam turbine, a passport of the initial data of in-turbine units and parts, parameters of the blade apparatus by stages, their limiting criteria for wear and damage are entered into the database. This allows, during endoscopy, to carry out a comparative analysis of the state of units, parts, blades of the flow parts of a steam turbine.

The matching and expansion units are designed for image input, probe control, reception, conversion and transmission of signals from probes and a synchronization sensor, generation of high-frequency pulses of the indication time scale.

Video probes (flexible and rigid) are designed for video and photo recording of the state of the blades and damper connections. The video probes fit into the endoscope assembly and include a multi-channel video head with cable. The number of video probes in the system is specified when designing the system for a specific turbine and depends on the shooting distance and the size of the areas of the surfaces of the turbine flow path elements that need to be monitored.

A multichannel video head is an optoelectronic device consisting of several small-sized video cameras installed on a common electronic board at a certain distance from each other. The video head also includes a controllable main LED backlight that can be used in both continuous and pulsed modes. In addition to the main illumination, the video head includes structured illumination designed to determine the scale factor for different areas of the resulting images.

The structured illumination is realized with a laser diode and a structured diffuser.

The unit for creating a light flux of various directions is designed to receive and transmit to the receiver of the beam channel the radiation modulated by the working blades from the continuous light source located in the video probe, convert it into an electrical signal, amplify and transmit this signal to the interface unit.

The synchronization sensor is designed to identify the location of the blades during multiple inspections.

The synchronization sensor includes two main components: a zero position sensor and a steering angle sensor. The zero position sensor provides information about the start of a new turn. An optical reflective sensor is used as a zero position sensor in combination with a reflective mark rigidly attached to the shaft. The steering angle sensor measures the angle of rotation of the shaft relative to the start position. The steering angle sensor includes a code strip wrapped around the turbine rotor and rigidly attached thereto, and a reader. The tape is encoded and read by optical-mechanical (mechanical cutting of a raster on a tape and reading it by an optical method) or magnetically (applying a magnetic code to the tape and reading it using a specialized device). In this case, the code for each angular position must be unique - this makes it possible to read the angular position even when the turbine is completely stopped.

The reflective mark is an element rigidly fixed to the shaft, operating on the principle of a corner reflector. The radiation emitted by the radiation source of the reflective sensor is reflected strictly in the opposite direction and falls on its radiation receiver.

Lines and blocks of communication allow using the capabilities of incoming elements for digital processing and communication with the server.

All actions to determine the location of the endoscopic unit with respect to receiving data from the video probes are consistent with a calibrated synchronization sensor located permanently on the shaft of the steam turbine, and, using feedback through the data processing unit, controls the location of the video probes relative to the blade apparatus and elements of the flow path. These capabilities can be achieved with multiple cameras that capture the full length of the scapula when inserting a multiple endoscope probe.

Data processing includes several main stages:

- determining the number of the blade in the frame according to the readings of the synchronization sensor at the time of shooting,

- multi-angle integration (stitching) of images obtained in the course of one shooting operation using different channels of a multichannel video endoscope,

- measurement of the deviation of the shape of the blade from the ideal by means of morphological image processing, taking into account the scale factor connecting the size of the part in the image (in pixels) with its real size obtained using structured illumination.

Multi-angle image integration is carried out using any technology known from the prior art.

For the system to function, it is necessary to determine the correspondence between the angle of rotation of the shaft and the position of the vane in the frame of the video head. For this, at each stage, an initial calibration is carried out as follows.

1. During calibration, the turbine rotates with a barring device at a low speed (no more than 3 rpm).

2. A multichannel video endoscope is inserted into the turbine to the required depth and at the angle that is optimal for shooting the blades.

3. The video stream transmission from the multichannel video endoscope is switched on. In this case, each frame of the video stream is marked with synchronization data.

4. The video stream is recorded in one complete revolution (the time interval between two signals from the zero position sensor).

5. The operator will review the video frame by frame, choosing the pictures in which each of the blades is in the most suitable position for shooting.

6. Synchronization marks (angular positions of the shaft) corresponding to each image selected by the operator are stored and can be used to obtain synchronized images of specific blades.

The use of a multichannel video endoscope makes it possible to obtain images of all blades automatically in one turbine revolution without the need to reposition the imaging device itself.

Synchronization of shooting is achieved through the use of a two-component device, which includes an optical reflective sensor and a sensor of the angle of rotation based on a code strip.

A more accurate measurement of defects is carried out by determining the regional scale of the image using structured illumination, which creates a periodic pattern on all observed surfaces (ruled, checkered, circular). The scale of each individual section of the observed surfaces can be determined by the size of the elements of the created pattern and / or the distance between these elements.

The use of tools for morphological processing of images of the blades allows you to automatically measure deviations of the shape of the edges from the ideal for each specific blade.

The endoscopy system automatically provides:

- visual measuring control;

- control with a closed LPC and HPC for the most erosion-prone link of the blade apparatus and in-turbine elements;

- video monitoring of all erosion-hazardous elements of rotor blades, inlet and outlet edges, fastening wires and shroud;

- planning the required volume of repair work of the flow path elements to restore the rotor blades or replace them during the upcoming repair campaigns;

- determination of the dynamics of wear of the leading and trailing edges and the blade shroud, predicting emergency-hazardous wear levels of rotor blades, as well as assessing the erosion resistance of the applied protective coatings, which is extremely important to ensure the extension of the resource, increase the safety and reliability of the flow path elements;

- forecast of the residual life of the blades according to their actual wear parameters with the preservation of the full amount of information in digital form during the entire service life of the blades (using histograms, graphs).

In accordance with the above calibration procedure, the angular positions of the shaft corresponding to each vane are determined. Thus, during monitoring, it is possible to determine which blade is in the frame by the current angular position of the shaft. For example, during monitoring, an image of a blade was taken - the angle of rotation of the shaft at the time of shooting is 272 degrees 33 minutes, the automated system compares this image with the closest angular position recorded during calibration, and the data is displayed that this is blade No. 97.

The process is automated through synchronization, morphological image processing and automatic scaling through structured illumination.

Monitoring and measurements are performed as follows.

1. The shaft passes the angular position corresponding to, for example, vane no. 42.

2. The steering angle sensor detects this and sends a signal that the shaft is "on vane # 42".

3. Capturing images using the video head.

4. Images are stitched together.

5. On the "sewn" image, the scale and shape of the part is determined, taking into account the scale.

6. The deviation from the norm is measured.

7. The result is recorded: Blade No. 42 - the maximum value of the edge defect is 8 mm.

8. A decision is made - No repair needed / Repair needed / Replacement needed.

Claims (2)

1. A system for monitoring the state of in-turbine units and turbine parts, consisting of locks to provide access without opening the turbine flow parts during operation both at barring and at complete shutdown of turbines, video probes included in the endoscopic unit with a recorder, a unit for creating a luminous flux of various directionality, a server that provides reception, storage and processing of primary data, sensing data of the elements of the turbine flow parts, a synchronization sensor, lines and communication units, characterized in that the video probe contains a multi-channel video head, which is an optoelectronic device consisting of several small-sized video cameras, controlled LED illumination and structured illumination, and the synchronization sensor consists of a zero position sensor, which is an optical reflective sensor with a reflective mark and rigidly attached to the shaft, and a rotation angle sensor, including a code strip, wrapped around the turbine rotor and rigidly fixed to it, and a reader, while the tape is encoded and read by optical-mechanical or magnetic means, while the code of each angular position is unique. 2. A method for monitoring the elements of the turbine flow path, including placing video probes in the turbine flow path, controlling the video probes to receive frames, transferring and processing the received data on the server, characterized in that for the analysis of the information received, the server contains the data of passports of the initial data of the in-turbine assemblies and parts , parameters of the blade apparatus by stages, their limiting criteria for wear and damage, determination of the position of the endoscopic unit is carried out in relation to the acquisition of data from the video probes, coordinating with a calibrated synchronization sensor located permanently on the turbine shaft, and by feedback through the data processing unit, the location of the video probes relative to of the blade apparatus and elements of the flow path, data processing includes determining the number of the blade in the frame according to the readings of the synchronization sensor at the time of shooting, multi-angle complexing of images obtained in the process of one operation shooting with the help of different channels of a multichannel video endoscope, measuring the deviation of the blade shape from the ideal by means of morphological image processing, taking into account the scale factor obtained using structured illumination, while preliminarily before measurements, the correspondence between the angle of rotation of the shaft and the position of the blade in the video head frame is determined, including primary calibration, containing the introduction of the video endoscope into the turbine to the required depth and at the optimal angle for shooting the blades when the turbine rotates with a barring device at a speed of no more than 3 rpm, recording the video stream for a full revolution, with each frame of the video stream being marked with synchronization data , with the subsequent selection of images in the most suitable position and saving them for later use to obtain synchronized images of specific blades.