Hydro-generator water head measuring and correcting method

Abstract

The invention belongs to the technical field of hydropower station water-turbine generator sets, and particularly provides a water-turbine generator water head measuring and correcting method which comprises the following steps: S1, mounting various water level measuring devices; the upstream water level and the downstream water level are calculated according to the corresponding water level data obtained by the multiple water level measuring devices in the step S1, the water head is the difference value of the upstream water level and the downstream water level, and multiple calculated water heads are obtained; s3, water head selection: selecting multiple groups of calculation water heads obtained in the step S2, and selecting credible water heads; and S4, water head filtering: filtering the credible water head selected in the step S3, and taking the filtered credible water head as an operation water head of the power station. According to the method, multiple water head measurement modes are added, and the accuracy and reliability of water head calculation are greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydroelectric turbine generator units, and specifically relates to a method for measuring and correcting the head of a hydrogenerator. Background Art

[0002] The head of a water turbine refers to the energy difference of a unit weight of water body at the inlet and outlet of the water turbine, which reflects the effective degree of the conversion of water flow potential energy into mechanical energy. The size of the head directly affects the output power and efficiency of the water turbine. In the operation and maintenance of hydropower stations, the unit of the water turbine head is usually meters. The change of the head will cause the change of the operating conditions of the water turbine. Therefore, accurately measuring the water turbine head is crucial for the dispatching and operation of the power station.

[0003] CN118601788A discloses a method for configuring the generating head of a hydropower unit, including the following steps: S1, calculating the redundant configuration of the head; S2, effective head calculation strategy; S3, head anomaly handling method; The present invention provides a reasonable configuration method and locking logic for the generating head of a hydropower unit, ensuring the reliability, effectiveness, and reasonableness of the head. It provides a one-key unlocking method after the head fault is locked, which can unlock the head more intelligently and safely, reducing cumbersome manual operations. It has a head measurement function during faults, which can effectively help dispatchers analyze and judge the actual head in case of head faults, reducing the regulation pressure. However, the head measurement method is single and the reliability is insufficient. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for measuring and correcting the head of a hydrogenerator, increasing the accuracy and reliability of the head measurement of the hydrogenerator.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: a method for measuring and correcting the head of a hydrogenerator, including the following steps: S1, installing a variety of water level measuring devices; S2, head calculation: calculating the upstream and downstream water levels through the corresponding water level data obtained by the variety of water level measuring devices in step S1, and the head is the difference between the upstream and downstream water levels, obtaining a variety of calculated heads; S3, head selection: selecting from the multiple groups of calculated heads obtained in step S2 to select a credible head; S4, head filtering: filtering the credible head selected in step S3, and taking the filtered credible head as the operating head of the power station.

[0006] In a preferred solution, in step S1, the water level measuring device includes a pressure type water level gauge, an ultrasonic water level sensor, a water gauge, and a video monitoring device supporting the water gauge.

[0007] In the preferred solution, the pressure water level gauge is installed in the upstream area h of the hydropower station p1 elevation and in the upstream area h of the hydropower station p2 elevation; the ultrasonic water level sensor is installed at the elevation h on the upstream side of the dam top of the hydropower station r1 and at the elevation h on the downstream side of the dam top of the hydropower station r2 ; the water gauge and the video monitoring equipment supporting the water gauge are installed at the riverside of the downstream basin of the hydropower station.

[0008] In the preferred solution, in the step S2, the calculation process of the upstream and downstream water levels by the pressure water level gauge is as follows: the upstream water level , the downstream water level , in the above formula 、 are the pressure signals of the pressure water level gauges deployed upstream and downstream respectively, is the local atmospheric pressure, is the liquid density of the Yangtze River, is the local acceleration of gravity; The head calculated by using the data collected by the pressure water level gauge is ΔH p =H p1 -H p2 , which is called the pressure water level gauge head.

[0009] In the preferred solution, in the step S2, the calculation process of the upstream and downstream water levels by the ultrasonic water level sensor is as follows: the upstream water level , the downstream water level , where: 、 are the round-trip time differences of the acoustic pulses from the upstream and downstream ultrasonic transmitters to the liquid surface respectively, is the propagation speed of sound; The head calculated by using the data collected by the ultrasonic water level sensor is ΔH r =H r1 -H r2 , which is called the ultrasonic water level sensor head.

[0010] In the preferred solution, in the step S2, the process of calculating the upstream and downstream water levels by the water gauge and the supporting video monitoring equipment is as follows: collect the water gauge image I and perform preprocessing to obtain the enhanced image I′ = Preprocess(I), extract the text region R closest to the water level line = TextDetection(I′), and perform text recognition to obtain the water level value H v = TextRecognition(R), and thus obtain the upstream and downstream water levels H v1 、H v2 ; The head calculated by using the data collected by the video monitoring equipment is ΔHv =H v1 -H v2 , which is called the video surveillance water head.

[0011] In a preferred solution, in step S3, the water head selection includes the following operations: Compare each calculated water head with the water head calculated from the data of the previous acquisition cycle, calculate the water head difference between the two cycles. If the absolute value of a certain water head difference is less than 1 m, it is determined that the water head collected by the corresponding water level measuring device is credible; otherwise, it is not credible. If the water head is not credible, enter the locked state, and the data measured by the corresponding water level measuring device does not participate in the water head calculation process; When multiple water heads are all credible, perform a correlation analysis on the multiple water heads. When there is only one water head whose absolute value of the difference from the other water heads is greater than the threshold δ, it is determined that this water head is not credible and enter the locked state; When there is at least 1 credible water head, set the water head priority to obtain the water head WH with the highest priority and credibility; When multiple water heads are all not credible, use the water head H of the centralized control center c as the credible water head WH.

[0012] In a preferred solution, the water head priority is the water head ΔH of the ultrasonic water level sensor r > the water head ΔH of the video surveillance v > the water head ΔH of the pressure type water level gauge p .

[0013] In a preferred solution, the threshold δ is set to 1 m.

[0014] In a preferred solution, in step S4, use the sliding median average filtering method to smooth the credible water head WH, and the operation is as follows: S401. Consider N credible water heads WH as a queue. Each time a new data is sampled, put it at the end of the queue and delete an original data at the head of the queue; S402. Remove the maximum and minimum values in the queue and do not participate in the average calculation; S403. Calculate the arithmetic average of N - 2 data to obtain the smoothed water head WH smooth , and use it as the operating water head of the power station.

[0015] A water head measurement and correction method for a hydrogenerator provided by the present invention has the following beneficial effects: 1. A variety of water level measurement devices, such as pressure water level gauges, ultrasonic water level sensors, water gauges, and video monitoring equipment, work together to obtain water level data from different principles and perspectives. The multiple methods complement each other, effectively reducing the possible errors of a single measurement method, making the measurement results closer to the actual water level, and thus greatly improving the accuracy of head calculation.

[0016] 2. In the head selection process, by comparing the head differences in different acquisition cycles, conducting head correlation analysis, and setting head priorities, etc., abnormal data can be effectively excluded. When a certain measurement device fails or is interfered with, resulting in abnormal data, such as the head measured by the pressure water level gauge in a certain cycle being too different from that in other cycles, by comparing with the data in the previous acquisition cycle, it can be determined that the data is not credible and avoided from participating in the calculation; when multiple heads are all credible, if there is a certain head with a too large difference from other heads, it can also be judged as not credible to ensure the reliability of the finally selected head data. Even if multiple heads are all not credible, the head of the centralized control center can be used as a backup, further ensuring the reliability of the measurement.

[0017] 3. The sliding median average filtering method is used to smooth the credible head. By continuously updating the data queue, removing the maximum and minimum values, and then taking the arithmetic average, the noise and sudden interference signals in the measurement process can be effectively filtered out. For example, in actual operation, there may be short-term water level fluctuations or momentary interference of the measurement equipment. After this filtering process, the obtained operating head data is more stable and accurate, providing a reliable basis for the stable operation and precise scheduling of the power station.

[0018] 4. Accurate and reliable head measurement provides key data support for the scheduling and operation of the power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a flowchart of the method of the present invention; Figure 2 It is a diagram of the head calculation steps; Figure 3 It is a flowchart of the selection of credible head. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0023] As Figure 1 shown, a method for measuring and correcting the water head of a hydrogenerator includes the following steps: S1. Installation of multiple water level measuring devices.

[0024] The water level measuring devices include a pressure type water level gauge, an ultrasonic water level sensor, a water gauge and a video monitoring device supporting the water gauge.

[0025] Specifically, (1) install a pressure type water level gauge at the elevation h p1 in a region with smooth water flow and no sediment accumulation in the upper reaches of the hydropower station; (2) install an ultrasonic water level sensor at the elevation h r1 on the upstream side of the dam crest of the hydropower station; (3) install a water gauge and a supporting video monitoring device on the riverbank in the upper reaches of the hydropower station; (4) install a pressure type water level gauge at the elevation h p2 in a region with smooth water flow and no sediment accumulation in the lower reaches of the hydropower station; (5) install an ultrasonic water level sensor at the elevation h r2 on the downstream side of the dam crest of the hydropower station; (6) install a water gauge and a supporting video monitoring device on the riverbank in the lower reaches of the hydropower station. The above-mentioned sensors and video monitoring systems transmit electrical signals and video streams to the computer monitoring system of the hydropower station through media such as optical fibers and cables.

[0026] S2. Water head calculation: As Figure 2 shown, the upstream and downstream water levels are calculated based on the corresponding water level data obtained by the multiple water level measuring devices in step S1, and the water head is the difference between the upstream and downstream water levels, obtaining multiple calculated water heads.

[0027] The calculation process of the upstream and downstream water levels by the pressure type water level gauge is: upstream water level , downstream water level , in the above formula 、 are the pressure signals of the pressure type water level gauges deployed upstream and downstream respectively, is the local atmospheric pressure, is the liquid density of the Yangtze River, is the local acceleration of gravity.

[0028] The calculation process of calculating the upstream and downstream water levels through the ultrasonic water level sensor is: upstream water level , downstream water level , where: 、 are the round-trip time differences of the sound pulses from the upstream and downstream ultrasonic transmitters to the liquid surface respectively, is the propagation speed of sound.

[0029] The process of calculating the upstream and downstream water levels by the water gauge and the supporting video monitoring equipment is as follows: Collect the water gauge image I and perform preprocessing, including grayscale conversion, binarization, denoising, etc., to obtain the enhanced image I′ = Preprocess(I), extract the text region R closest to the water level line = TextDetection(I′), and a text detection model can be used for extraction. For example, the EAST text detection model can be used, and then text recognition is performed to obtain the water level value H v = TextRecognition(R). Specifically, text recognition is performed through a text recognition model, such as CRNN, to obtain the upstream and downstream water levels H v1 、H v2 .

[0030] According to different water level measurement devices, calculate the difference between the upstream and downstream water levels to obtain various calculated water heads. The sampling and the upstream and downstream water level calculation periods are both set to 1 s to obtain the water head ΔH of the pressure type water level gauge p = H p1 - H p2 , the water head ΔH of the ultrasonic water level sensor r = H r1 - H r2 , the water head ΔH of the video monitoring v = H v1 - H v2 .

[0031] S3. Water head selection: As Figure 3 shown, select the credible water heads from the multiple groups of calculated water heads obtained in step S2.

[0032] The water head selection includes the following operations: Compare the calculated water heads of each type with the water heads calculated from the data of the previous acquisition period, calculate the difference in water heads between the two periods. If the absolute value of the difference in a certain water head is less than 1 m, it is determined that the water head collected by the corresponding water level measurement device is credible; otherwise, it is not credible. If the water head is not credible, enter the locked state, and the data measured by the corresponding water level measurement device does not participate in the water head calculation process.

[0033] When multiple water heads are all credible, in this embodiment, when three water heads are all credible, perform a correlation analysis on the multiple water heads. When there is one and only one case where the absolute value of the difference between a certain water head and the other water heads is greater than the threshold δ, that is, ∃x∈{ΔH p ,ΔH r ,ΔH v},∀y∈{ΔH p ,ΔH r ,ΔH v}\{x},∣x−y∣>δ, it is determined that this water head is not credible, enter the locked state, and the data measured by the corresponding water level measurement device does not participate in the water head calculation process. The threshold δ is set to 1 m.

[0034] When there is at least 1 kind of credible water head, set the water head priority to obtain the highest-priority and credible water head WH.

[0035] The water head priority is that the water head ΔH of the ultrasonic water level sensor r > the water head ΔH of the video surveillance v > the water head ΔH of the pressure type water level gauge p .

[0036] When multiple water heads are all not credible, use the water head H at the centralized control center c as the credible water head WH. The priority of the water head H at the centralized control center c is lower than that of the three water heads.

[0037] The locked state of the water head can be unlocked by the operator's order in the monitoring system.

[0038] S4. Water head filtering: Filter the credible water heads selected in step S3, and use the filtered credible water heads as the operating water heads of the power station.

[0039] Use the sliding median average filtering method to smooth the credible water head WH, and the operation is as follows: S401. Take N credible water heads WH as a queue. Each time a new data is sampled, it is put into the end of the queue, and an original data at the head of the queue is deleted. N is generally set to 20; S402. Remove the maximum and minimum values in the queue and do not participate in the average calculation; S403. Calculate the arithmetic average of N - 2 data to obtain the smoothed water head WH smooth, and use it as the operating head of the power station.

[0040] Compared with the conventional head measurement and selection methods of existing hydropower stations, the present invention adds various head measurement methods, greatly increasing the accuracy and reliability of head calculation.

[0041] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring and correcting the water head of a hydro-generator, characterized in that It includes the following steps: S1. Install a variety of water level measuring devices; S2. Head calculation: Calculate the upstream and downstream water levels through the corresponding water level data obtained by the variety of water level measuring devices in step S1. The head is the difference between the upstream and downstream water levels, and a variety of calculated heads are obtained; S3. Head selection: Select from the multiple groups of calculated heads obtained in step S2 to select a credible head; S4. Head filtering: Filter the credible head selected in step S3, and use the filtered credible head as the operating head of the power station.

2. A water turbine generator head measurement and correction method according to claim 1, characterized in that, In the said step S1, the water level measuring device includes a pressure type water level gauge, an ultrasonic water level sensor, a water gauge and a video monitoring device supporting the water gauge.

3. A water turbine generator head measurement and correction method according to claim 2, characterized in that, The pressure water level gauge is installed at the elevation h in the upstream area of the hydropower station p1 and at the elevation h in the upstream area of the hydropower station p2 ; the ultrasonic water level sensor is installed at the elevation h on the upstream side of the dam crest of the hydropower station r1 and at the elevation h on the downstream side of the dam crest of the hydropower station r2 ; the water gauge and the video monitoring equipment supporting the water gauge are installed at the riverside of the downstream basin of the hydropower station.

4. A method for measuring and correcting the water head of a hydrogenerator according to claim 2, characterized in that, In the step S2, the calculation process of the upstream and downstream water levels by the pressure water level gauge is as follows: the upstream water level , the downstream water level . In the above formula and are the pressure signals of the pressure water level gauges deployed upstream and downstream respectively, is the local atmospheric pressure, is the liquid density of the Yangtze River, is the local acceleration of gravity; The head calculated from the data collected by the pressure water level gauge is ΔH p =H p1 -H p2 , which is called the head of the pressure water level gauge.

5. A water turbine generator head measurement and correction method according to claim 2, characterized in that, In the step S2, the calculation process of calculating the upstream and downstream water levels by the ultrasonic water level sensor is as follows: the upstream water level , the downstream water level , where: and are the round-trip time differences of the acoustic pulses from the upstream and downstream ultrasonic transmitters to the liquid surface respectively, is the propagation speed of sound; The head calculated from the data collected by the ultrasonic water level sensor is ΔH r =H r1 -H r2 , which is called the head of the ultrasonic water level sensor.

6. A method for measuring and correcting the water head of a hydro-generator according to claim 2, characterized in that, In the step S2, the process of calculating the upstream and downstream water levels through the water gauge and the supporting video monitoring device is as follows: collecting the water gauge image I and performing preprocessing to obtain the enhanced image I′, extracting the text area closest to the water level line, and performing text recognition to obtain the water level value H v , thereby obtaining the upstream and downstream water levels H v1 , H v2 ; The head calculated using the data collected by the video surveillance device is ΔH v =H v1 -H v2 , which is called the video surveillance head.

7. A water turbine generator head measurement and correction method according to claim 2, characterized in that, In the said step S3, the head selection includes the following operations: Compare each calculated head with the head calculated from the data of the previous acquisition period, calculate the head difference between the two periods. If the absolute value of a certain head difference is less than 1m, it is determined that the head collected by the corresponding water level measuring device is credible; otherwise, it is not credible. If the head is not credible, it enters the locked state, and the data measured by the corresponding water level measuring device does not participate in the head calculation process; When multiple heads are all credible, conduct a correlation analysis on the multiple heads. When there is only one head whose absolute value of the difference from the other heads is greater than the threshold δ, determine that this head is not credible and enter the locked state; When there is at least 1 credible head, set the head priority to obtain the head WH with the highest priority and credibility; When multiple water heads are not credible, the water head H of the centralized control center c is used as the credible water head WH.

8. A method for measuring and correcting the water head of a hydrogenerator according to claim 7, characterized in that, The water head priority is the water head ΔH of the ultrasonic water level sensor r > the water head ΔH of the video surveillance v > the water head ΔH of the pressure type water level gauge p .

9. A water turbine generator head measurement and correction method according to claim 7, characterized in that, The threshold δ is set to 1m.

10. A method for measuring and correcting the water head of a hydrogenerator according to claim 7, characterized in that, In the said step S4, use the sliding median average filtering method to smooth the credible head WH, and the operation is as follows: S401. Take N credible heads WH as a queue. Each time a new data is sampled, it is put into the end of the queue, and the original data at the head of the queue is deleted; S402. Remove the maximum and minimum values in the queue and do not participate in the average calculation; S403. Calculate the arithmetic mean of N - 2 data to obtain the smoothed water head WH smooth , and use it as the operating water head of the power station.

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