A method and system for monitoring the water level of a hydro-generator top cover

Abstract

The present application belongs to the field of liquid level measurement, and relates to a water level monitoring method and system for a top cover of a hydroelectric generating set, comprising the following steps: S1, obtaining float switch water level information, first liquid level transmitter water level information and second liquid level transmitter water level information; S2, obtaining a first liquid level transmitter measurement value and a second liquid level transmitter measurement value; S3, if the judgment result is no, then performing start-stop control of a drainage pump according to the first liquid level transmitter measurement value and the second liquid level transmitter measurement value; if the judgment result is yes, then obtaining a float switch water level switch value, and selecting the float switch water level switch value and the first liquid level transmitter measurement value or the float switch water level switch value and the second liquid level transmitter measurement value to perform start-stop control of the drainage pump. The present application solves the problems of low reliability and low accuracy of existing top cover water level monitoring by using a float switch and two liquid level transmitters to perform start-stop control of the drainage pump with three options for two.

Description

Technical Field

[0001] This invention relates to the field of liquid level measurement, and specifically discloses a method and system for monitoring the water level on the top cover of a hydro-generator unit. Background Technology

[0002] Due to factors such as water supply for the main shaft seal lubrication and backflow at the runner seal, water continuously accumulates inside the top cover of the hydroelectric generator unit in hydropower stations. To ensure the safe operation of the turbine unit and prevent accidents caused by rising water levels leading to flooding of the top cover and the turbine generator unit, it is necessary to drain the accumulated water from the top cover in a timely manner. Therefore, a highly reliable drainage method is extremely necessary. However, to properly drain the water from the top cover, the drainage pump needs to be controlled based on the detected water level. Therefore, a highly reliable and accurate water level monitoring method is a prerequisite for the normal drainage process. Currently, traditional top cover water level monitoring methods often rely on a single water level float switch or level transmitter to measure and monitor the water level. Therefore, traditional top cover water level monitoring methods mainly have the following problems:

[0003] (1) Low reliability. Using a single water level measuring element can lead to problems such as component quality issues, aging after long-term operation, harsh operating environment, and inadequate maintenance, resulting in inaccurate water level measurement and low reliability of water level monitoring, which in turn affects the normal operation of drainage.

[0004] (2) Low accuracy. The working environment of the water level monitoring element inside the top cover is poor, and the mechanical vibration during the operation of the hydro-generator unit will cause the water level inside the top cover to fluctuate. The vibration of the top cover will cause the accumulated water to impact the side wall of the top cover, resulting in the instability of the transmitter that measures the water pressure to reflect the water level, that is, the water level measurement will deviate, affecting the accuracy of water level monitoring. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for monitoring the water level on the top cover of a hydro-generator unit, thereby solving the problems of low reliability and low accuracy in existing top cover water level monitoring systems.

[0006] The specific solution of the present invention is as follows:

[0007] A method for monitoring the water level on the top cover of a hydro-generator unit includes the following steps:

[0008] S1. Obtain the water level information of the float switch, the water level information of the first level transmitter, and the water level information of the second level transmitter;

[0009] S2. After verifying the correctness of the measurements of the first and second level transmitters based on the water level information of the first and second level transmitters respectively, the measured values ​​of the first and second level transmitters are obtained by median filtering.

[0010] S3. Determine whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information. If the determination result is negative, control the start and stop of the drainage pump based on the measurement values ​​of the first and second level transmitters. If the determination result is positive, obtain the float switch water level switch quantity. Based on the float switch water level switch quantity, the measurement values ​​of the first and second level transmitters, select the combination of the float switch water level switch quantity and the measurement value of the first or second level transmitters to control the start and stop of the drainage pump.

[0011] In some embodiments, the start / stop control of the drainage pump is performed by selecting the float switch level switch quantity and the measured value of the first level transmitter or the float switch level switch quantity and the measured value of the second level transmitter, including:

[0012] Determine whether the difference between the measured value of the first level transmitter and the measured value of the second level transmitter is less than or equal to the deviation set value. If the determination result is no, then the start and stop control of the drainage pump is based on the level switch quantity of the float switch and the measured value of the first level transmitter.

[0013] If the judgment result is yes, then it is determined whether the float switch level switch quantity is equal to the value measured by the first level transmitter. If the judgment result is no, then the start and stop control of the drainage pump is based on the float switch level switch quantity and the value measured by the first level transmitter. If the judgment result is yes, then the start and stop control of the drainage pump is based on the float switch level switch quantity and the value measured by the second level transmitter.

[0014] In some embodiments, the start-stop control of the drainage pump is based on the level switch input of the float switch and the measurement value of the first level transmitter, including:

[0015] The system checks whether the float switch level indicator and the first level transmitter reading have reached the pump start setting. If the float switch level indicator has reached the pump start setting, the system controls the drainage pump to start and drain water. After the drainage pump drains water, the system checks whether the float switch level indicator has reached the pump stop setting. If the result is yes, the system controls the drainage pump to stop working. If the result is no, the drainage pump continues to drain water.

[0016] If the judgment result is that the value measured by the first level transmitter has reached the pump start setting value, then the drain pump is controlled to start and drain water based on the value measured by the first level transmitter. After the drain pump drains water, it is judged whether the value measured by the first level transmitter has reached the pump stop setting value. If the judgment result is yes, the drain pump is controlled to stop working. If the judgment result is no, the drain pump continues to drain water.

[0017] In some embodiments, determining whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information includes:

[0018] The float switch water level information includes the pump stop water level float signal, the main pump start water level float signal, the first standby pump start water level float signal, the second standby pump start water level float signal, and the high water level alarm float signal;

[0019] Based on the water level from low to high, the system determines whether the float switch water level information is sequentially: pump stop water level float signal, main pump start water level float signal, first standby pump start water level float signal, second standby pump start water level float signal, and high water level alarm float signal. If the determination result is yes, the float switch passes the correctness test of each float action logic; if the determination result is no, the float switch fails the correctness test of each float action logic.

[0020] In some embodiments, the accuracy of the measurements of the first and second level transmitters is verified based on the water level information from the first and second level transmitters, respectively, including:

[0021] Based on the water level information from the first and second level transmitters, the upper and lower limit amplitude tests, the jump test of the measured values ​​before and after the cycle, and the test of no change in the measured values ​​within the cumulative cycle are performed on the first and second level transmitters respectively.

[0022] In some embodiments, a second water level alarm step is further included, the second water level alarm step comprising:

[0023] Based on the measurements from the first level transmitter, the second level transmitter, and the acquired third level transmitter, a water level deviation alarm signal, a water level sensor fault alarm signal, and a water level abnormal change alarm signal are generated, respectively. Water level deviation alarm, water level sensor fault alarm, and water level abnormal change alarm are then triggered according to the water level deviation alarm signal, water level sensor fault alarm signal, and water level abnormal change alarm signal, respectively.

[0024] In some embodiments, the acquired third level transmitter measurement includes:

[0025] The water level information of the third level transmitter is obtained. After verifying the accuracy of the measurement of the third level transmitter based on the water level information, the measurement value of the third level transmitter is obtained by median filtering.

[0026] In some embodiments, the verification of the accuracy of the measurement value of the third level transmitter includes:

[0027] Based on the water level information from the third level transmitter, the upper and lower limit amplitude tests, the jump test of the measured value before and after the cycle, and the test of no change in the measured value within the cumulative cycle are performed on the third level transmitter.

[0028] This invention also relates to a water level monitoring system for the top cover of a hydro-generator unit, comprising:

[0029] The data acquisition module is used to collect water level information from the float switch, the first level transmitter, the second level transmitter, and the third level transmitter.

[0030] The liquid level transmitter measurement acquisition module is used to verify the correctness of the measurements of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter based on the water level information of the first liquid level transmitter, the water level information of the second liquid level transmitter, and the water level information of the third liquid level transmitter, and then obtain the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter respectively through the median filtering method.

[0031] The drainage pump start / stop control module is used to determine whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information. If the determination result is negative, the drainage pump is started / stopped based on the measurement values ​​of the first and second level transmitters. If the determination result is positive, the float switch water level switch quantity is obtained, and the drainage pump is started / stopped based on the float switch water level switch quantity, the measurement values ​​of the first and second level transmitters, or the float switch water level switch quantity and the measurement value of the second level transmitter.

[0032] In some embodiments, a second water level alarm module is further included, which is used to generate a water level deviation alarm signal, a water level sensor fault alarm signal, and a water level abnormal change alarm signal based on the measurement values ​​of the first water level transmitter, the second water level transmitter, and the third water level transmitter, respectively, and to perform water level deviation alarm, water level sensor fault alarm, and water level abnormal change alarm based on the water level deviation alarm signal, the water level sensor fault alarm signal, and the water level abnormal change alarm signal, respectively.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. This invention uses a float switch and two level transmitters, employing a three-to-two selection method to control the start and stop of the drainage pump. This solves the problems of low accuracy and reliability in water level monitoring caused by faults or inaccurate water level measurement deviations of a single water level measuring element. By using multi-point water level monitoring elements with different principles, it solves the problem of water level measurement failure caused by faults in a single water level measuring element or equipment failure under specific working conditions due to a single principle, thus improving the accuracy and reliability of top cover water level monitoring.

[0035] 2. A second water level alarm is generated through three level transmitters, and one level transmitter is not involved in the start / stop control of the drainage pump but is directly used for water level alarm, realizing multiple monitoring and alarm. When the first water level alarm fails, an alarm can be triggered in time through the second water level alarm, which improves the redundancy and reliability of the top cover water level monitoring. Attached Figure Description

[0036] Figure 1 This is a flowchart of a method for monitoring the water level on the top cover of a hydro-generator unit according to an embodiment of the present invention.

[0037] Figure 2 This is a block diagram of a water level monitoring system for the top cover of a hydro-generator unit according to an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0039] A method for monitoring the water level on the top cover of a hydro-generator unit, such as Figure 1 As shown, it includes the following steps:

[0040] S1. Obtain the water level information of the float switch and the water level information of each level transmitter;

[0041] Water level information at corresponding monitoring points is collected in real time using multiple water level measuring elements. There are four water level measuring elements: one float switch and three level transmitters. The three level transmitters are designated as the first, second, and third level transmitters, and the water level information from each transmitter includes the water level information from the first, second, and third level transmitters. In the circular water storage area of ​​the top cover, the four water level monitoring elements are evenly distributed along the circumference. There are four water level information points: the float switch water level, the first level transmitter water level, the second level transmitter water level, and the third level transmitter water level.

[0042] A float switch and any two level transmitters are used to control the start and stop of the drainage pump to achieve drainage control. A first and second level transmitter are preset to control the start and stop of the drainage pump. By deploying multiple level measuring elements, the redundancy of the top cover water level monitoring can be improved, reducing the risk of low accuracy and reliability of drainage due to the failure of a single level measuring element, which is present when only a single element is deployed.

[0043] In top-cover drainage, there is a possibility of the drainage pump malfunctioning or failing to start. The requirements for malfunction and failure to start are contradictory. Since a failure to start the drainage pump can cause a serious accident, preventing failure to start is a priority. Therefore, for the three water level measuring elements involved in controlling the drainage pump start—two level transmitters and a float switch—at least two water level measuring elements participate in the pump start control. The logic is that when a start signal from any water level measuring element arrives, the drainage pump is started; when a stop signal from the water level measuring element that triggered the start signal arrives, the drainage pump stops. This avoids situations where a single water level measuring element malfunctions or its measurement is inaccurate or unreliable, preventing the timely start of the drainage pump to remove water accumulated in the top cover.

[0044] Three level transmitters are used for water level alarms. One level transmitter is not involved in the start / stop control of the drainage pump and is used directly for water level alarms. The third level transmitter is preset to be used directly for water level alarms and is not involved in the start / stop control of the drainage pump. By performing logical operations on the water level information measured by the three level transmitters to generate water level alarm signals, the accuracy and reliability of the top cover water level monitoring can be improved. At the same time, it can cope with situations where a single water level monitoring element fails, or the drainage pump experiences power failure, shutdown, or other malfunctions, resulting in the inability to monitor the water level inside the top cover, thus realizing multiple monitoring of the water level inside the top cover.

[0045] Among them, the float switch is a liquid level control device that uses a magnetic float to trigger a signal as the liquid level rises and falls. It achieves liquid level monitoring and signal transmission by driving the switch action through magnetic force. Its working principle is that the float switch consists of a float, a magnet and a switching unit. When the liquid level in the container changes, the float rises and falls accordingly. When the float approaches the switching unit, it triggers the internal magnetic reed switch on / off control circuit to realize the detection and transmission of liquid level signals.

[0046] A level transmitter is an industrial device that measures liquid level based on the principle of hydrostatic pressure. It converts changes in liquid pressure into a standard electrical signal output. Its working principle is based on the proportional relationship between liquid hydrostatic pressure and height. When the liquid level rises, the pressure on the sensor diaphragm increases, and this displacement change is converted into an electrical signal output. The level transmitter is a water level sensor.

[0047] S2. Based on the water level information of each level transmitter, the correctness of the measurement value of each level transmitter is checked. If a level transmitter passes the correctness of the measurement value, the measurement value of the level transmitter is obtained by median filtering. If a level transmitter fails the correctness of the measurement value, the first water level alarm is issued for the level transmitter.

[0048] The water level information of each level transmitter is as follows: water level information of the first level transmitter, water level information of the second level transmitter, and water level information of the third level transmitter. The water level information of the first level transmitter corresponds to the first level transmitter, the water level information of the second level transmitter corresponds to the second level transmitter, and the water level information of the third level transmitter corresponds to the third level transmitter.

[0049] S21. Based on the water level information of each level transmitter, perform upper and lower limit amplitude tests on each level transmitter. If a level transmitter passes the upper and lower limit amplitude test, proceed to the next step. If a level transmitter fails the upper and lower limit amplitude test, issue the first water level alarm for that level transmitter.

[0050] Determine whether the water level information of a certain level transmitter falls between the upper and lower limits of the corresponding level transmitter. If the determination result is yes, the level transmitter corresponding to the water level information passes the upper and lower limit test and proceeds to the next step; if the determination result is no, the level transmitter corresponding to the water level information fails the upper and lower limit test, a first water level alarm signal for the level transmitter is generated, and a first water level alarm is issued for the level transmitter based on the first water level alarm signal.

[0051] S22. Based on the water level information of each level transmitter, perform a jump test on the measurement value of each level transmitter before and after the cycle. If a level transmitter passes the jump test on the measurement value of each cycle, proceed to the next step. If a level transmitter fails the jump test on the measurement value of each cycle, issue the first water level alarm for that level transmitter.

[0052] The system determines whether the difference between the current cycle's water level information and the previous cycle's water level information of a certain level transmitter exceeds a first threshold. If the result is yes, it indicates that the difference between the current cycle's water level information and the previous cycle's water level information is too large, causing a water level jump. Therefore, the level transmitter fails the inter-cycle measurement jump test, and a first water level alarm signal is generated. Based on this first water level alarm signal, the system performs the following steps on the level transmitter: A water level alarm is triggered. If the water level jumps, the test for jumps between previous and next cycle measurements fails. This is because the water level inside the top cover increases slowly, so a sudden, large increase in water level inside the top cover is impossible. If the result is negative, it means that the difference between the water level information of the current cycle and the water level information of the previous cycle of a certain level transmitter is not large, and the increase in water level inside the top cover is within the normal range without a jump. In this case, the level transmitter passes the test for jumps between previous and next cycle measurements and proceeds to the next step.

[0053] S23. Based on the water level information of each level transmitter, perform a cumulative periodic test to check if the measured value of each level transmitter has no change. If a level transmitter passes the cumulative periodic test, proceed to the next step. If a level transmitter fails the cumulative periodic test, issue a first water level alarm for that level transmitter.

[0054] The system determines whether the current water level information of a certain level transmitter is equal to the water level information of the previous water level within the cumulative period. If the determination result is yes, it means that the water level information of the certain level transmitter has not changed within the cumulative period, and the certain level transmitter has failed the test of no change in measured value within the cumulative period. A first water level alarm signal is generated for the certain level transmitter, and a first water level alarm is issued for the certain level transmitter based on the first water level alarm signal. If the water level has not changed within the cumulative period, it fails the test of no change in measured value within the cumulative period because the water accumulation inside the top cover is slowly and continuously increasing, so the water accumulation inside the top cover cannot remain unchanged. If the determination result is no, it means that the water level information of the certain level transmitter has changed within the cumulative period, and the certain level transmitter has passed the test of no change in measured value within the cumulative period, and proceeds to the next step.

[0055] After a level transmitter passes a measurement accuracy check, its measured level is obtained by median filtering based on the level information provided by the transmitter. Specifically, the first level transmitter, after passing a measurement accuracy check based on its level information, obtains its measured level through median filtering; the second level transmitter, after passing a measurement accuracy check based on its level information, obtains its measured level through median filtering; and the third level transmitter, after passing a measurement accuracy check based on its level information, obtains its measured level through median filtering.

[0056] Median filtering is a non-linear smoothing technique that sets the gray value of each pixel to the median of the gray values ​​of all pixels within a certain neighborhood window of that pixel.

[0057] S3. Based on the float switch water level information, determine whether the float switch has passed the correctness check of the operation logic of each float. If the determination result is no, then control the start and stop of the drainage pump according to the measurement value of the first level transmitter and the measurement value of the second level transmitter, and issue the first water level alarm. If the determination result is yes, obtain the float switch water level switch quantity, and based on the float switch water level switch quantity, the measurement value of the first level transmitter and the measurement value of the second level transmitter, select the float switch water level switch quantity and the measurement value of the first level transmitter or the float switch water level switch quantity and the measurement value of the second level transmitter to control the start and stop of the drainage pump.

[0058] Based on the water level information of the float switch, determine whether the float switch has passed the logic correctness check of each float's action, specifically including:

[0059] The float switch includes multiple floats arranged sequentially. Along the top cover, from bottom to top, are: a pump stop level float, a main pump start level float, a first standby pump start level float, a second standby pump start level float, and a high level alarm float. The float switch provides water level information including pump stop level float signals and pump start level float signals. The pump start level float signals include signals for the main pump start, the first standby pump start, the second standby pump start, and the high level alarm float.

[0060] Based on the water level from low to high, the system determines whether the float switch water level information is sequentially: pump stop water level float signal, main pump start water level float signal, first standby pump start water level float signal, second standby pump start water level float signal, and high water level alarm float signal. If the determination result is yes, it indicates that the operation logic of each float of the float switch is correct, and the float switch passes the test of the correctness of the operation logic of each float. The float switch can participate in the start-stop control of the drainage pump and proceed to the next step. If the determination result is no, it indicates that the operation logic of each float of the float switch is disordered, and the float switch fails the test of the correctness of the operation logic of each float. The float switch cannot work normally, cannot participate in the start-stop control of the drainage pump, and generates a first water level alarm signal for the float switch. The first water level alarm is then triggered based on the first water level alarm signal of the float switch.

[0061] For example, when the water level inside the top cover is low, the float switch water level information should be the pump stop water level float signal. However, if the obtained float switch water level information is any one of the following: the main pump start water level float signal, the first standby pump start water level float signal, the second standby pump start water level float signal, or the high water level alarm float signal, it indicates that the float switch's float action logic is incorrect and the float switch cannot work properly. In this case, the float switch fails the correctness test of each float action logic and generates a first water level alarm signal. The first water level alarm is then triggered based on the first water level alarm signal.

[0062] Alternatively, if the water level inside the top cover is higher than the water level near the top cover, the float switch water level information should be a high water level alarm float signal. However, if the obtained float switch water level information is any one of the following: pump stop water level float signal, main pump start water level float signal, first standby pump start water level float signal, or second standby pump start water level float signal, it indicates that the float switch's float action logic is incorrect and the float switch cannot work properly. In this case, the float switch fails the correctness test of each float action logic and generates a first water level alarm signal for the float switch. The first water level alarm is then triggered based on the first water level alarm signal for the float switch.

[0063] The start and stop control of the drainage pump is based on the readings from the first and second level transmitters, specifically including:

[0064] The system determines whether the values ​​measured by the first and second level transmitters have reached the pump start setting value. If the first level transmitter value has reached the pump start setting value, the first level transmitter participates in the start-stop control of the drainage pump. The drainage pump is started to drain water according to the value measured by the first level transmitter, thus realizing pump start control. After the drainage pump drains water, the system determines whether the first level transmitter value has reached the pump stop setting value. If the result is yes, the drainage pump stops working. If the result is no, the drainage pump continues to drain water.

[0065] If the judgment result is that the value measured by the second level transmitter reaches the pump start setting value, the second level transmitter participates in the start and stop control of the drainage pump. Based on the value measured by the second level transmitter, the drainage pump is started to drain water, thus realizing the pump start control. After the drainage pump drains water, it is judged whether the value measured by the second level transmitter reaches the pump stop setting value. If the judgment result is yes, the drainage pump stops working. If the judgment result is no, the drainage pump continues to drain water.

[0066] Based on the float switch level indicator, the readings from the first and second level transmitters, the start / stop control of the drainage pump is selected by combining the float switch level indicator with the reading from the first or second level transmitter. Specifically, this includes:

[0067] Determine whether the difference between the measured value A of the first level transmitter and the measured value B of the second level transmitter is less than or equal to the deviation set value, i.e., |AB|≤ the deviation set value, which can be 10cm. If the determination result is no, the float switch and the first level transmitter participate in the start-stop control of the drainage pump. The start-stop control of the drainage pump is performed based on the water level switch quantity of the float switch and the measured value of the first level transmitter, and a first water level alarm signal of the level transmitter is generated. The first water level alarm is triggered based on the first water level alarm signal of the level transmitter.

[0068] If the judgment result is yes, then it is determined whether the float switch level switch quantity C is equal to the measured value A of the first level transmitter, i.e., C=A; if the judgment result is no, then the float switch and the first level transmitter participate in the start-stop control of the drainage pump, and the start-stop control of the drainage pump is performed based on the float switch level switch quantity and the measured value of the first level transmitter, and a first level alarm signal of the level transmitter is generated, and a first level alarm is triggered based on the first level alarm signal of the level transmitter; if the judgment result is yes, then the float switch and the second level transmitter participate in the start-stop control of the drainage pump, and the start-stop control of the drainage pump is performed based on the float switch level switch quantity and the measured value of the second level transmitter.

[0069] Note that the equality between the float switch level reading and the first level transmitter reading includes both absolute equality and relative equality. Relative equality means that the float switch level reading and the first level transmitter reading are considered equal within a preset range.

[0070] The start / stop control of the drainage pump is based on the level switch input of the float switch and the measurement value of the first level transmitter, including:

[0071] The system determines whether the float switch level switch quantity and the value measured by the first level transmitter have reached the pump start setting value. If the result is that the float switch level switch quantity has reached the pump start setting value, the float switch participates in the start and stop control of the drainage pump. The system controls the drainage pump to start and drain water according to the float switch level switch quantity, thus realizing the pump start control. After the drainage pump drains water, the system determines whether the float switch level switch quantity has reached the pump stop setting value. If the result is yes, the system controls the drainage pump to stop working. If the result is no, the drainage pump continues to drain water.

[0072] If the judgment result is that the value measured by the first level transmitter reaches the pump start setting value, the first level transmitter participates in the start and stop control of the drainage pump. Based on the value measured by the first level transmitter, the drainage pump is started to drain water, thus realizing the pump start control. After the drainage pump drains water, it is judged whether the value measured by the first level transmitter reaches the pump stop setting value. If the judgment result is yes, the drainage pump is controlled to stop working. If the judgment result is no, the drainage pump continues to drain water.

[0073] The start / stop control of the drainage pump is based on the level switch output of the float switch and the measurement value of the second level transmitter, including:

[0074] The system determines whether the level switch output of the float switch and the measured value of the second level transmitter have reached the pump start setting value. If the result is that the level switch output of the float switch has reached the pump start setting value, the float switch participates in the start and stop control of the drainage pump. The drainage pump is started to drain water according to the level switch output of the float switch, thus realizing the pump start control. After the drainage pump drains water, the system determines whether the level switch output of the float switch has reached the pump stop setting value. If the result is yes, the drainage pump is controlled to stop working. If the result is no, the drainage pump continues to drain water.

[0075] If the judgment result is that the value measured by the second level transmitter reaches the pump start setting value, the second level transmitter participates in the start and stop control of the drainage pump. Based on the value measured by the second level transmitter, the drainage pump is controlled to start and drain water, thus realizing pump start control. After the drainage pump drains water, it is judged whether the value measured by the second level transmitter reaches the pump stop setting value. If the judgment result is yes, the drainage pump is controlled to stop working. If the judgment result is no, the drainage pump continues to drain water.

[0076] By using a float switch and two level transmitters, and employing a three-to-two selection method for the start-stop control of the drainage pump, the problem of low accuracy and reliability in water level monitoring caused by faulty or inaccurate water level measurement of a single water level measuring element is solved. This eliminates the possibility of pump failure due to situations where the measurement value passes the accuracy test but is stuck, has excessive deviation, or shows no change when controlling the start-stop of the drainage pump using a single water level measuring element, which could further prevent the drainage of water from the top cover. By using multi-point water level monitoring elements with different principles, the problem of water level measurement failure caused by faulty single water level measuring elements or equipment failure under specific operating conditions due to a single principle is solved, thus improving the accuracy and reliability of water level monitoring of the top cover.

[0077] S4. Generate a second alarm signal based on the measured values ​​of each level transmitter to trigger a second water level alarm.

[0078] The measured values ​​of each level transmitter are the measured values ​​of the first level transmitter, the second level transmitter, and the third level transmitter, respectively. The second alarm signal includes the water level deviation alarm signal, the water level sensor fault alarm signal, and the water level abnormal change alarm signal. The second water level alarm includes the water level deviation alarm, the water level sensor fault alarm, and the water level abnormal change alarm.

[0079] S41. Generate a water level deviation alarm signal based on the measured values ​​of each level transmitter to perform a water level deviation alarm.

[0080] Based on the water level measurements from the first, second, and third level transmitters, the maximum and minimum water level measurements from the level transmitters are obtained. It is then determined whether the difference between the maximum and minimum water level measurements exceeds a second threshold. If the result is yes, a water level deviation alarm signal is generated to trigger a water level deviation alarm. If the result is no, no water level deviation alarm signal is generated, and no water level deviation alarm is triggered.

[0081] Simultaneously, it determines whether the difference between any two level transmitters exceeds a third threshold. If the result is yes, a level deviation alarm signal is generated; otherwise, no alarm signal is generated. The difference between any two level transmitters refers to the difference between the level readings of the first and second level transmitters, the difference between the level readings of the first and third level transmitters, and the difference between the level readings of the second and third level transmitters.

[0082] S42. Generate a water level sensor fault alarm signal based on the measured values ​​of each level transmitter to trigger a water level sensor fault alarm.

[0083] The system determines whether the water level readings of the first, second, and third level transmitters are within the measurement range. If the result is negative, it indicates that the water level reading of one of the level transmitters is abnormal, or that the water level readings of the three transmitters are inconsistent, indicating a fault in the level transmitter. In this case, a water level sensor fault alarm signal is generated. If the result is positive, it indicates that the water level reading of one of the level transmitters is normal. In this case, no water level sensor fault alarm signal is generated, and no water level sensor fault alarm is triggered.

[0084] S43. Generate an alarm signal for abnormal water level changes based on the measured values ​​of each level transmitter to trigger an alarm for abnormal water level changes.

[0085] Based on the water level readings of each level transmitter in the current cycle, determine whether the difference between the water level reading of the current level transmitter in the current cycle and the water level reading of the previous cycle is greater than a fourth threshold. If the determination result is yes, it indicates that the water level reading of the level transmitter has risen or fallen rapidly in the current cycle, resulting in an abnormal water level change, and an abnormal water level change alarm signal is generated to trigger an alarm. If the determination result is no, no abnormal water level change alarm signal is generated, and no abnormal water level change alarm is triggered.

[0086] Simultaneously, based on the current water level measurement value of a certain level transmitter, it is determined whether the difference between the current water level measurement value and the previous water level measurement value is greater than the fifth threshold. If the determination result is yes, it indicates that the fluctuation range of the water level measurement value of a certain level transmitter is too large at a certain moment, and an abnormal water level change has occurred. In this case, an abnormal water level change alarm signal is generated to trigger an alarm. If the determination result is no, no abnormal water level change alarm signal is generated, and no abnormal water level change alarm is triggered.

[0087] The second water level alarm is generated by three level transmitters, and one level transmitter is not involved in the start / stop control of the drainage pump but is directly used for water level alarm, realizing multiple monitoring and alarm. When the first water level alarm fails, the second water level alarm can be triggered in time, which improves the redundancy and reliability of the top cover water level monitoring.

[0088] This invention also relates to a water level monitoring system for the top cover of a hydro-generator unit, used in the aforementioned method for monitoring the water level of the top cover of a hydro-generator unit, such as... Figure 2 As shown, it includes:

[0089] The data acquisition module is used to collect water level information from the float switch, the first level transmitter, the second level transmitter, and the third level transmitter.

[0090] The liquid level transmitter measurement acquisition module is used to verify the correctness of the measurements of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter based on the water level information of the first liquid level transmitter, the water level information of the second liquid level transmitter, and the water level information of the third liquid level transmitter, and then obtain the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter respectively through the median filtering method.

[0091] The drainage pump start / stop control module is used to determine whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information. If the determination result is negative, the drainage pump is started / stopped based on the measurement values ​​of the first and second level transmitters. If the determination result is positive, the float switch water level switch quantity is obtained, and the drainage pump is started / stopped based on the float switch water level switch quantity, the measurement values ​​of the first and second level transmitters, or the float switch water level switch quantity and the measurement value of the second level transmitter.

[0092] The first water level alarm module is used to generate a first water level alarm signal based on the water level information of the float switch, the water level information of the first liquid level transmitter, the water level information of the second liquid level transmitter, and the water level information of the third liquid level transmitter, and to perform a first water level alarm based on the first water level alarm signal. The first water level alarm signal includes the first water level alarm signal of the first liquid level transmitter, the first water level alarm signal of the second liquid level transmitter, the first water level alarm signal of the third liquid level transmitter, the first water level alarm signal of the float switch, and the first water level alarm signal of the liquid level transmitter.

[0093] The second water level alarm module is used to generate water level deviation alarm signals, water level sensor fault alarm signals, and water level abnormal change alarm signals based on the measurements of the first water level transmitter, the second water level transmitter, and the third water level transmitter. Based on the water level deviation alarm signals, water level sensor fault alarm signals, and water level abnormal change alarm signals, water level deviation alarms, water level sensor fault alarms, and water level abnormal change alarm signals are generated respectively.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for monitoring the water level on the top cover of a hydro-generator unit, characterized in that, Includes the following steps: S1. Obtain the water level information of the float switch, the water level information of the first level transmitter, and the water level information of the second level transmitter; S2. After verifying the correctness of the measurements of the first and second level transmitters based on the water level information of the first and second level transmitters respectively, the measured values ​​of the first and second level transmitters are obtained by median filtering. S3. Determine whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information. If the determination result is no, control the start and stop of the drainage pump based on the measurement values ​​of the first and second level transmitters. If the determination result is yes, obtain the float switch water level switch quantity. Based on the float switch water level switch quantity, the measurement values ​​of the first and second level transmitters, select the float switch water level switch quantity and the measurement value of the first or second level transmitters to control the start and stop of the drainage pump. The method of selecting the float switch level switch value and the measurement value of the first level transmitter or the float switch level switch value and the measurement value of the second level transmitter to control the start and stop of the drainage pump includes: Determine whether the difference between the measured value of the first level transmitter and the measured value of the second level transmitter is less than or equal to the deviation set value. If the determination result is no, then the start and stop control of the drainage pump is based on the level switch quantity of the float switch and the measured value of the first level transmitter. If the judgment result is yes, then it is determined whether the float switch level switch quantity is equal to the value measured by the first level transmitter. If the judgment result is no, then the start and stop control of the drainage pump is based on the float switch level switch quantity and the value measured by the first level transmitter. If the judgment result is yes, then the start and stop control of the drainage pump is based on the float switch level switch quantity and the value measured by the second level transmitter.

2. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 1, characterized in that, The start / stop control of the drainage pump based on the float switch level switch input and the measurement value of the first level transmitter includes: The system checks whether the float switch level indicator and the first level transmitter reading have reached the pump start setting. If the float switch level indicator has reached the pump start setting, the system controls the drainage pump to start and drain water. After the drainage pump drains water, the system checks whether the float switch level indicator has reached the pump stop setting. If the result is yes, the system controls the drainage pump to stop working. If the result is no, the drainage pump continues to drain water. If the judgment result is that the value measured by the first level transmitter has reached the pump start setting value, then the drain pump is controlled to start and drain water based on the value measured by the first level transmitter. After the drain pump drains water, it is judged whether the value measured by the first level transmitter has reached the pump stop setting value. If the judgment result is yes, the drain pump is controlled to stop working. If the judgment result is no, the drain pump continues to drain water.

3. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 1, characterized in that, The step of determining whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information includes: The float switch water level information includes the pump stop water level float signal, the main pump start water level float signal, the first standby pump start water level float signal, the second standby pump start water level float signal, and the high water level alarm float signal. Based on the water level from low to high, the system determines whether the float switch water level information is sequentially: pump stop water level float signal, main pump start water level float signal, first standby pump start water level float signal, second standby pump start water level float signal, and high water level alarm float signal. If the determination result is yes, the float switch passes the correctness test of each float action logic; if the determination result is no, the float switch fails the correctness test of each float action logic.

4. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 1, characterized in that, The verification of the accuracy of the measurements from the first and second level transmitters, based on the water level information from the first and second level transmitters respectively, includes: Based on the water level information from the first and second level transmitters, the upper and lower limit amplitude tests, the jump test of the measured values ​​before and after the cycle, and the test of no change in the measured values ​​within the cumulative cycle are performed on the first and second level transmitters, respectively.

5. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 1, characterized in that, It also includes a second water level alarm step, which includes: Based on the measurements from the first level transmitter, the second level transmitter, and the acquired third level transmitter, a water level deviation alarm signal, a water level sensor fault alarm signal, and a water level abnormal change alarm signal are generated, respectively. Water level deviation alarm, water level sensor fault alarm, and water level abnormal change alarm are then triggered according to the water level deviation alarm signal, water level sensor fault alarm signal, and water level abnormal change alarm signal, respectively.

6. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 5, characterized in that, The acquired third level transmitter readings include: The water level information of the third level transmitter is obtained. After verifying the accuracy of the measurement of the third level transmitter based on the water level information, the measurement value of the third level transmitter is obtained by median filtering.

7. The method for monitoring the water level on the top cover of a hydro-generator unit according to claim 6, characterized in that, The accuracy verification of the third level transmitter's readings includes: Based on the water level information from the third level transmitter, the upper and lower limit amplitude tests, the jump test of the measured value before and after the cycle, and the test of no change in the measured value within the cumulative cycle are performed on the third level transmitter.

8. A water level monitoring system for the top cover of a hydro-generator unit, characterized in that, A method for monitoring the water level on the top cover of a hydro-generator unit according to any one of claims 1-7, comprising: The data acquisition module is used to collect water level information from the float switch, the first level transmitter, the second level transmitter, and the third level transmitter. The liquid level transmitter measurement acquisition module is used to verify the correctness of the measurements of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter based on the water level information of the first liquid level transmitter, the water level information of the second liquid level transmitter, and the water level information of the third liquid level transmitter, and then obtain the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter, and the third liquid level transmitter respectively through the median filtering method. The drainage pump start / stop control module is used to determine whether the float switch has passed the correctness check of the operation logic of each float ball based on the float switch water level information. If the determination result is negative, the drainage pump is started / stopped based on the measurement values ​​of the first and second level transmitters. If the determination result is positive, the float switch water level switch quantity is obtained, and the drainage pump is started / stopped based on the float switch water level switch quantity, the measurement values ​​of the first and second level transmitters, or the float switch water level switch quantity and the measurement value of the second level transmitter.

9. A water level monitoring system for the top cover of a hydro-generator unit according to claim 8, characterized in that: It also includes a second water level alarm module, which is used to generate a water level deviation alarm signal, a water level sensor fault alarm signal, and a water level abnormal change alarm signal based on the measurement values ​​of the first water level transmitter, the second water level transmitter, and the third water level transmitter, respectively. Based on the water level deviation alarm signal, the water level sensor fault alarm signal, and the water level abnormal change alarm signal, water level deviation alarm, water level sensor fault alarm, and water level abnormal change alarm are respectively used to perform water level deviation alarm, water level sensor fault alarm, and water level abnormal change alarm.

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