Water-turbine generator set top cover water level monitoring method and system

Abstract

The invention belongs to the field of liquid level measurement, and relates to a water-turbine generator set top cover water level monitoring method and system, and the method comprises the following steps: S1, obtaining the water level information of a float switch, the water level information of a first liquid level transmitter and the water level information of a second liquid level transmitter; s2, obtaining a first liquid level transmitter measurement value and a second liquid level transmitter measurement value; s3, if the judgment result is no, starting and stopping control over the drainage pump is carried out according to the first liquid level transmitter measurement value and the second liquid level transmitter measurement value; if the judgment result is yes, the water level switching value of the float switch is obtained, and the water level switching value of the float switch and the measured value of the first liquid level transmitter or the water level switching value of the float switch and the measured value of the second liquid level transmitter are selected to conduct start-stop control over the drainage pump. Through the float switch and the two liquid level transmitters, two-out-of-three participates in starting and stopping control of the drainage pump, and the problems that existing top cover water level monitoring is low in reliability and accuracy are solved.

Description

Technical Field

[0001] The invention relates to the field of liquid level measurement, and in particular discloses a method and system for monitoring the water level of a top cover of a hydro-generator set. Background Art

[0002] The top cover of the hydroelectric generator set in a hydropower station is constantly filled with water due to the lubrication of the main shaft seal and the backflow of water at the runner seal. In order to ensure the safe operation of the turbine unit and prevent the water level from rising and causing the top cover and the turbine generator set to be flooded, the water in the top cover must be drained in time, so a highly reliable drainage method is extremely necessary. However, in order to drain the water in the top cover normally, the drainage pump must be controlled according to the detected water level. Therefore, a highly reliable and accurate water level monitoring method will be a necessary condition for the normal drainage of the drainage method. At present, the traditional top cover water level monitoring method often uses a single water level float switch or liquid level transmitter to measure and monitor the water level. Therefore, the traditional top cover water level monitoring method mainly has the following problems: (1) Low reliability. Using a single water level measuring element may lead to problems such as component quality issues, aging after long-term operation, harsh operating environment, and inadequate maintenance, resulting in problems such as single water level measuring element failure and inaccurate water level measurement offset. This leads to low reliability of water level monitoring, thus affecting the normal operation of drainage.

[0003] (2) Low accuracy. The poor working environment of the water level monitoring element in the top cover and the mechanical vibration during the operation of the hydro-generator set will cause the water level in the top cover to fluctuate. The vibration of the top cover causes the accumulated water to impact the side wall of the top cover, resulting in unstable measurement of the transmitter that reflects the water level by measuring water pressure, that is, water level measurement offset, affecting the accuracy of water level monitoring. Summary of the Invention

[0004] The object of the present invention is to provide a method and system for monitoring the water level of a top cover of a hydro-generator set, so as to solve the problems of low reliability and low accuracy of existing top cover water level monitoring.

[0005] The specific scheme of the present invention is as follows: A method for monitoring the water level of a hydro-generator top cover comprises the following steps: S1. Obtaining water level information of the float switch, the first liquid level transmitter, and the second liquid level transmitter; S2. After performing a correctness check on the measured values ​​of the first liquid level transmitter and the second liquid level transmitter based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter, respectively, obtaining the measured values ​​of the first liquid level transmitter and the second liquid level transmitter respectively by using a median filtering method; S3. Determine whether the float switch passes the logic correctness test of each float action based on the float switch water level information. If the judgment result is no, perform start and stop control of the drainage pump based on the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter. If the judgment result is yes, obtain the water level switch value of the float switch. Based on the water level switch value of the float switch, the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter, select the water level switch value of the float switch and the measurement value of the first liquid level transmitter or the water level switch value of the float switch and the measurement value of the second liquid level transmitter to perform start and stop control of the drainage pump.

[0006] In some embodiments, 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 start and stop the drainage pump includes: Determine whether the difference between the measured value of the first liquid level transmitter and the measured value of the second liquid level transmitter is less than or equal to the deviation set value. If the judgment result is not, start and stop control of the drainage pump is performed based on the water level switch value of the float switch and the measured value of the first liquid level transmitter; If the judgment result is yes, then determine whether the water level switch value of the float switch is equal to the measurement value of the first liquid level transmitter. If the judgment result is no, then control the start and stop of the drainage pump based on the water level switch value of the float switch and the measurement value of the first liquid level transmitter. If the judgment result is yes, then control the start and stop of the drainage pump based on the water level switch value of the float switch and the measurement value of the second liquid level transmitter.

[0007] In some embodiments, starting and stopping the drainage pump based on the water level switch value of the float switch and the measured value of the first liquid level transmitter includes: respectively judging whether the water level value of the float switch and the measured value of the first liquid level transmitter have reached the pump start setting value; if the judgment result shows that the water level value of the float switch has reached the pump start setting value, then controlling the drainage pump to start drainage according to the water level value of the float switch; after the drainage pump has drained water, judging whether the water level value of the float switch has reached the pump stop setting value; if the judgment result is yes, then controlling the drainage pump to stop working; if the judgment result is no, then controlling the drainage pump to continue drainage; If the judgment result is that the measured value of the first liquid level transmitter reaches the pump start setting value, the drainage pump is controlled to start and drain water based on the measured value of the first liquid level transmitter; after the drainage pump drains water, it is judged whether the measured value of the first liquid 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.

[0008] In some embodiments, determining whether the float switch passes the logic correctness test of each float action based on the float switch water level information includes: The water level information of the float switch includes the water level float signal of stopping the pump, the water level float signal of starting the main pump, the water level float signal of starting the first standby pump, the water level float signal of starting the second standby pump and the high water level alarm float signal; Based on the water level from low to high, determine whether the water level information of the float switch is, in sequence, 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. If the judgment result is yes, the float switch passes the logic correctness test of each float action; if the judgment result is no, the float switch fails the logic correctness test of each float action.

[0009] In some embodiments, performing a measurement accuracy check of the first liquid level transmitter and the second liquid level transmitter based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter, respectively, includes: Based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter, the upper and lower limit tests of the first liquid level transmitter and the second liquid level transmitter are respectively performed, the jump test of the measured values ​​before and after the cycle and the test of no change in the measured value within the cumulative cycle are performed.

[0010] In some embodiments, a second water level alarm step is further included, and the second water level alarm step includes: Based on the measurement value of the first liquid level transmitter, the measurement value of the second liquid level transmitter and the obtained measurement value of the third liquid level transmitter, a water level deviation alarm signal, a water level sensor failure alarm signal and a water level abnormal change alarm signal are generated respectively; and according to the water level deviation alarm signal, the water level sensor failure alarm signal and the water level abnormal change alarm signal, a water level deviation alarm, a water level sensor failure alarm and a water level abnormal change alarm are respectively performed.

[0011] In some embodiments, the third level transmitter measurement value obtained includes: The water level information of the third liquid level transmitter is obtained, and after the correctness of the measured value of the third liquid level transmitter is checked according to the water level information of the third liquid level transmitter, the measured value of the third liquid level transmitter is obtained by using a median filtering method.

[0012] In some embodiments, the correctness check of the measured value of the third liquid level transmitter includes: According to the water level information of the third liquid level transmitter, the upper and lower limit tests of the third liquid level transmitter, the jump test of the measured values ​​before and after the cycle, and the test of no change of the measured value within the cumulative cycle are respectively performed.

[0013] The present invention also relates to a water level monitoring system for a top cover of a hydro-generator set, comprising: A data acquisition module is used to collect water level information of the float switch, the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter; a liquid level transmitter measurement value acquisition module, configured to respectively verify the correctness of the measurement values ​​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 first liquid level transmitter measurement value, the second liquid level transmitter measurement value, and the third liquid level transmitter measurement value respectively through a median filtering method; The drainage pump start-stop control module is used to determine whether the float switch has passed the logic correctness test of each float action based on the float switch water level information. If the judgment result is no, the drainage pump start-stop control is performed according to the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter; if the judgment result is yes, the float switch water level switch value is obtained, and based on the float switch water level switch value, the first liquid level transmitter measurement value and the second liquid level transmitter measurement value, 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 are selected to perform the drainage pump start-stop control.

[0014] In some embodiments, a second water level alarm module is also included, which is used to generate a water level deviation alarm signal, a water level sensor failure alarm signal and a water level abnormal change alarm signal according to the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter, and to perform a water level deviation alarm, a water level sensor failure alarm and a water level abnormal change alarm based on the water level deviation alarm signal, the water level sensor failure alarm signal and the water level abnormal change alarm signal.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention uses a float switch and two liquid level transmitters, and adopts a three-choose-two method to participate in the start and stop control of the drainage pump, thereby solving the problem of low accuracy and low reliability of water level monitoring due to failure of a single water level measuring element and inaccurate water level measurement offset; through multi-point and different-principle water level monitoring elements, it solves the problem of water level measurement failure caused by failure of a single water level measuring element and failure of a single-principle equipment under specific working conditions, thereby improving the accuracy and reliability of top cover water level monitoring.

[0016] 2. The second water level alarm is performed through three liquid level transmitters, and one liquid level transmitter does not participate in the start and stop control of the drainage pump and is directly used for water level alarm, realizing multiple monitoring alarms. When the first water level alarm fails, the second water level alarm can be used in time to alarm, thereby improving the redundancy and reliability of the top cover water level monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of a method for monitoring the water level of a top cover of a hydro-generator set according to an embodiment of the present invention.

[0018] Figure 2The block diagram of a water level monitoring system for a hydro-generator cover according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] A method for monitoring the water level of a hydro-generator cover, such as Figure 1 As shown, the following steps are included: S1. Obtain the water level information of the float switch and each liquid level transmitter; Water level information from corresponding water level monitoring points is collected in real time using multiple water level measuring elements. These four elements consist of a float switch and three liquid level transmitters: the first, second, and third liquid level transmitters. Each transmitter provides water level information from the first, second, and third liquid level transmitters. Within the circular water storage area of ​​the top cover, the four water level monitoring elements are evenly spaced along the circumference. This provides four water level information sources: the float switch, the first, second, and third liquid level transmitters.

[0021] The float switch and any two level transmitters are used to control the start and stop of the drainage pump to achieve drainage control. The first and second level transmitters are preset to control the start and stop of the drainage pump. The deployment of multiple water level measuring elements improves the redundancy of the top cover water level monitoring and reduces the risk of low drainage accuracy and reliability caused by the failure of a single water level measuring element, which is common when only a single water level measuring element is deployed.

[0022] During top cover drainage, the drain pump may malfunction or fail to start. However, the requirements for malfunction and failure are conflicting. Since a failure to start the drain pump could cause a serious accident, preventing failure is a priority. Therefore, of the three water level measuring elements involved in controlling the drain pump's start—namely, two level transmitters and a float switch—at least two of them are involved in controlling the pump's start. The logic is that when a start signal arrives from any one of the water level measuring elements, the drain pump starts; when a stop signal arrives from the same water level measuring element that triggered the start signal, the drain pump stops. This prevents the drain pump from being able to start and drain the top cover water in a timely manner due to inaccurate and unreliable liquid level measurements caused by a single water level measuring element failure or measurement offset.

[0023] Three liquid level transmitters are used for water level alarms. One level transmitter is independent of the drainage pump start / stop control and is used directly for water level alarms. The third level transmitter is also pre-configured to be used directly for water level alarms and independent of the drainage pump start / stop control. By performing logical operations and generating water level alarm signals based on the water level information measured by the three level transmitters, the accuracy and reliability of top cover water level monitoring can be improved. This also addresses situations where a single water level monitoring component fails, or a drainage pump experiences a power outage or freeze, making it impossible to monitor the water level inside the top cover. This allows for multiple levels of water level monitoring inside the top cover.

[0024] 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, and realizes liquid level monitoring and signal transmission by driving the switch action by magnetic force; its working principle is that the float switch consists of a float, a magnet and a switch unit. When the liquid level in the container changes, the float rises and falls accordingly. When the float approaches the switch unit, it triggers the internal magnetic reed switch on-off control circuit to realize the detection and transmission of the liquid level signal.

[0025] A liquid level transmitter is an industrial device that measures liquid height based on the principle of liquid static pressure. It converts changes in liquid pressure into a standard electrical signal output. Its operating principle is to detect liquids by measuring the proportional relationship between static pressure and height. As the liquid level rises, the pressure on the sensor diaphragm increases, and the displacement change is converted into an electrical signal output. A liquid level transmitter is a water level sensor.

[0026] S2. Based on the water level information of each liquid level transmitter, the measurement accuracy of each liquid level transmitter is respectively checked. If a liquid level transmitter passes the measurement accuracy test, the measurement value of the liquid level transmitter is obtained by using the median filtering method. If a liquid level transmitter fails the measurement accuracy test, a first water level alarm is issued for the liquid level transmitter. The water level information of each liquid level transmitter is the first liquid level transmitter water level information, the second liquid level transmitter water level information and the third liquid level transmitter water level information. The first liquid level transmitter water level information corresponds to the first liquid level transmitter, the second liquid level transmitter water level information corresponds to the second liquid level transmitter, and the third liquid level transmitter water level information corresponds to the third liquid level transmitter.

[0027] S21. Perform upper and lower limit tests on each liquid level transmitter based on the water level information of each liquid level transmitter. If a liquid level transmitter passes the upper and lower limit tests, proceed to the next step. If a liquid level transmitter fails the upper and lower limit tests, issue a first water level alarm for the liquid level transmitter. Determine whether the water level information of a certain liquid level transmitter falls between the upper limit and the lower limit of the corresponding liquid level transmitter. If the judgment result is yes, the liquid level transmitter corresponding to the water level information of the certain liquid level transmitter passes the upper and lower limit inspections, and the next step is executed; if the judgment result is no, the liquid level transmitter corresponding to the water level information of the certain liquid level transmitter fails to pass the upper and lower limit inspections, and a first water level alarm signal of a certain liquid level transmitter is generated. According to the first water level alarm signal of the certain liquid level transmitter, a first water level alarm is issued to the certain liquid level transmitter.

[0028] S22. Perform a forward and backward cycle measurement value jump test on each liquid level transmitter based on the water level information of each liquid level transmitter. If a liquid level transmitter passes the forward and backward cycle measurement value jump test, execute the next step. If a liquid level transmitter fails the forward and backward cycle measurement value jump test, issue a first water level alarm for the liquid level transmitter. Determine whether the difference between the water level information of the current cycle of a certain level transmitter and the water level information of the previous cycle is greater than the first threshold value. If the judgment result is yes, it means that the difference between the water level information of the current cycle of a certain level transmitter and the water level information of the previous cycle is too large, and the water level jumps. The certain level transmitter fails the jump test of the measurement value before and after the previous cycle, and generates the first water level alarm signal of the certain level transmitter. The certain level transmitter is subjected to the first water level alarm signal. 1. Water level alarm; if the water level jumps, it fails the jump test of the previous and next cycle measurement value. This is because the water accumulation in the top cover increases slowly, so the water accumulation in the top cover cannot increase in a jump-like manner, that is, it cannot increase suddenly and significantly. If the judgment result is no, it means that the difference between the water level information of the current cycle of a certain liquid level transmitter and the water level information of the previous cycle is not large, and the increase of the water accumulation in the top cover does not increase in a jump-like manner within the normal range, then the certain liquid level transmitter passes the jump test of the previous and next cycle measurement value and executes the next step.

[0029] S23. Based on the water level information of each liquid level transmitter, a test is performed on each liquid level transmitter to see if the measured value has not changed within the cumulative period. If a liquid level transmitter passes the test to see if the measured value has not changed within the cumulative period, the next step is executed. If a liquid level transmitter fails to pass the test to see if the measured value has not changed within the cumulative period, the first water level alarm is issued for the liquid level transmitter.

[0030] Determine whether the water level information of a liquid level transmitter at the current moment is equal to the water level information of the liquid level transmitter at the previous moment within the cumulative period. If the judgment result is yes, it means that the water level information of the liquid level transmitter of a certain liquid level transmitter has not changed within the cumulative period, then the certain liquid level transmitter has not passed the test of no change in the measured value within the cumulative period, and a first water level alarm signal of a certain liquid level transmitter is generated. According to the first water level alarm signal of a certain liquid level transmitter, a first water level alarm is issued to the certain liquid level transmitter. If the water level has not changed within the cumulative period, the test of no change in the measured value within the cumulative period has not been passed because the accumulated water in the top cover increases slowly and continuously, so the accumulated water in the top cover cannot remain unchanged. If the judgment result is no, it means that the water level information of the liquid level transmitter of a certain liquid level transmitter has changed within the cumulative period, then the certain liquid level transmitter has passed the test of no change in the measured value within the cumulative period, and the next step is executed.

[0031] After a certain liquid level transmitter passes the measurement value correctness test, it uses the median filtering method to filter the measurement value based on the liquid level information of the liquid level transmitter to obtain the liquid level transmitter measurement value of the liquid level transmitter. That is, after the first liquid level transmitter passes the measurement value correctness test based on the first liquid level transmitter water level information, it uses the median filtering method to filter the measurement value to obtain the first liquid level transmitter water level measurement value; after the second liquid level transmitter passes the measurement value correctness test based on the second liquid level transmitter water level information, it uses the median filtering method to filter the measurement value to obtain the second liquid level transmitter water level measurement value; after the third liquid level transmitter passes the measurement value correctness test based on the third liquid level transmitter water level information, it uses the median filtering method to filter the measurement value to obtain the third liquid level transmitter water level measurement value.

[0032] Median filtering is a nonlinear smoothing technique that sets the grayscale value of each pixel to the median of the grayscale values ​​of all pixels within a certain neighborhood window of the point.

[0033] S3. Determine whether the float switch passes the logic correctness test of each float action based on the float switch water level information. If the judgment result is no, start and stop control of the drainage pump is performed based on the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter, and issue a first water level alarm. If the judgment result is yes, obtain the water level switch value of the float switch, and based on the water level switch value of the float switch, the measurement value of the first liquid level transmitter, and the measurement value of the second liquid level transmitter, select the water level switch value of the float switch and the measurement value of the first liquid level transmitter or the water level switch value of the float switch and the measurement value of the second liquid level transmitter to start and stop control of the drainage pump; Determine whether the float switch has passed the logic correctness test of each float action based on the float switch water level information, including: The float switch includes multiple floats arranged in sequence along the top cover. These include a pump-off float, a main pump-on float, a first backup pump-on float, a second backup pump-on float, and a high-water-level alarm float. The float switch's water level information includes pump-off and pump-on float signals. The pump-on float signals include the main pump-on, first backup pump-on, second backup pump-on, and high-water-level alarm signals.

[0034] Based on the water level from low to high, it is judged whether the water level information of the float switch is, in sequence, 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. If the judgment result is yes, it means that the action logic of each float of the float switch is correct, and the float switch passes the correctness test of each float action logic. The float switch can participate in the start and stop control of the drainage pump and executes the next step; if the judgment result is no, it means that the action logic of each float of the float switch is chaotic, and the float switch fails to pass the correctness test of each float action logic. The float switch cannot work normally and cannot participate in the start and stop control of the drainage pump, and generates a first water level alarm signal of the float switch. The first water level alarm of the float switch is issued according to the first water level alarm signal of the float switch.

[0035] For example, when the water level inside the top cover is low, the water level information of the float switch should be the pump-stop water level float signal. However, the water level information of the float switch obtained at this time is any one of 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, indicating that the float action logic of the float switch is incorrect and the float switch cannot work normally. The float switch fails the correctness test of each float action logic and generates the first water level alarm signal of the float switch. The first water level alarm of the float switch is issued according to the first water level alarm signal of the float switch.

[0036] Alternatively, when the water level inside the top cover is a high water level close to flooding the top cover, the water level information of the float switch should be a high water level alarm float signal, but the water level information of the float switch obtained at this time is any one of the pump stop water level float signal, the main pump start water level float signal, the first standby pump start water level float signal, and the second standby pump start water level float signal, indicating that the float action logic of the float switch is incorrect and the float switch cannot work normally. The float switch fails the correctness test of each float action logic and generates a first water level alarm signal of the float switch. The first water level alarm of the float switch is issued according to the first water level alarm signal of the float switch.

[0037] The start and stop control of the drainage pump is performed according to the measured values ​​of the first liquid level transmitter and the second liquid level transmitter, specifically including: It is judged respectively whether the measured value of the first liquid level transmitter and the measured value of the second liquid level transmitter reach the pump start setting value. If the judgment result is that the measured value of the first liquid level transmitter reaches the pump start setting value, the first liquid level transmitter participates in the start and stop control of the drainage pump, and controls the drainage pump to start and drain according to the measured value of the first liquid level transmitter to realize pump start control; after the drainage pump drains, it is judged whether the measured value of the first liquid 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.

[0038] If the judgment result is that the measured value of the second liquid level transmitter reaches the pump start setting value, the second liquid level transmitter participates in the start and stop control of the drainage pump, and controls the drainage pump to start and drain based on the measured value of the second liquid level transmitter to realize pump start control; after the drainage pump drains, it is judged whether the measured value of the second liquid 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.

[0039] Based on the water level switch value of the float switch, the measurement value of the first liquid level transmitter, and the measurement value of the second liquid level transmitter, the start and stop control of the drainage pump is performed by selecting the water level switch value of the float switch and the measurement value of the first liquid level transmitter or the water level switch value of the float switch and the measurement value of the second liquid level transmitter, specifically including: Determine whether the difference between the measured value A of the first liquid level transmitter and the measured value B of the second liquid level transmitter is less than or equal to the deviation set value, that is, |AB| ≤ the deviation set value, which can be 10cm. If the judgment result is no, the float switch and the first liquid level transmitter participate in the start and stop control of the drainage pump. The start and stop control of the drainage pump is performed based on the water level switch value of the float switch and the measured value of the first liquid level transmitter, and a first water level alarm signal of the liquid level transmitter is generated. The first water level alarm is issued according to the first water level alarm signal of the liquid level transmitter; If the judgment result is yes, then determine whether the water level switch value C of the float switch is equal to the measured value A of the first liquid level transmitter, that is, C=A; if the judgment result is no, then the float switch and the first liquid level transmitter participate in the start and stop control of the drainage pump, and the start and stop control of the drainage pump is performed based on the water level switch value of the float switch and the measured value of the first liquid level transmitter, and a first water level alarm signal of the liquid level transmitter is generated, and a first water level alarm is performed according to the first water level alarm signal of the liquid level transmitter. If the judgment result is yes, then the float switch and the second liquid level transmitter participate in the start and stop control of the drainage pump, and the start and stop control of the drainage pump is performed according to the water level switch value of the float switch and the measured value of the second liquid level transmitter.

[0040] Note that the equality between the water level switch value of the float switch and the measured value of the first liquid level transmitter includes absolute equality and relative equality. Relative equality means that the water level switch value of the float switch and the measured value of the first liquid level transmitter are considered equal within a preset range.

[0041] The start and stop control of the drainage pump is performed based on the water level switch value of the float switch and the measured value of the first liquid level transmitter, including: respectively judging whether the water level switch value of the float switch and the measured value of the first liquid level transmitter have reached the pump start setting value; if the judgment result is that the water level switch value 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, and controls the drainage pump to start and drain water according to the water level switch value of the float switch, thereby realizing pump start control; after the drainage pump has drained water, judging whether the water level switch value of the float switch has reached 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; If the judgment result is that the measured value of the first liquid level transmitter reaches the pump start setting value, the first liquid level transmitter participates in the start and stop control of the drainage pump, and controls the drainage pump to start and drain based on the measured value of the first liquid level transmitter to realize pump start control. After the drainage pump drains, it is judged whether the measured value of the first liquid 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.

[0042] The start and stop control of the drainage pump is carried out according to the water level switch value of the float switch and the measured value of the second liquid level transmitter, including: The float switch water level switch value and the second liquid level transmitter measurement value are judged respectively whether they have reached the pump start setting value. If the judgment result is that the float switch water level switch value has reached the pump start setting value, the float switch will participate in the start and stop control of the drainage pump. The drainage pump is controlled to start and drain water according to the float switch water level switch value to realize pump start control. After the drainage pump drains water, it is judged whether the float switch water level switch value has reached 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. If the judgment result is that the measured value of the second liquid level transmitter reaches the pump start setting value, the second liquid level transmitter participates in the start and stop control of the drainage pump, and controls the drainage pump to start and drain based on the measured value of the second liquid level transmitter to realize pump start control. After the drainage pump drains, it is judged whether the measured value of the second liquid 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.

[0043] Through a float switch and two liquid level transmitters, a three-choice two-out-of-three method is adopted to participate in the start and stop control of the drainage pump, which solves the problem of low accuracy and reliability of water level monitoring due to failure of a single water level measuring element, inaccurate water level measurement offset, etc., and eliminates the situation where the correctness test of the measured value is passed, but the measured value is stuck, the measured value deviation is too large, the measured value does not change, etc., which leads to the inability to start the pump, and further causes the inability to discharge the top cover water level; through multi-point and different principle water level monitoring elements, the problem of water level measurement failure caused by failure of a single water level measuring element, failure of equipment of a single principle under specific working conditions, etc. is solved, and the accuracy and reliability of top cover water level monitoring is improved.

[0044] S4. Generate a second alarm signal based on the measured values ​​of each liquid level transmitter to issue a second water level alarm.

[0045] The measured values ​​of each liquid level transmitter are the first liquid level transmitter measured value, the second liquid level transmitter measured value and the third liquid level transmitter measured value respectively. The second alarm signal includes a water level deviation alarm signal, a water level sensor failure alarm signal and a water level abnormal change alarm signal. The second water level alarm includes a water level deviation alarm, a water level sensor failure alarm and a water level abnormal change alarm.

[0046] S41, generating a water level deviation alarm signal based on the measured values ​​of each liquid level transmitter to perform a water level deviation alarm; According to the water level measurement value of the first liquid level transmitter, the water level measurement value of the second liquid level transmitter and the water level measurement value of the third liquid level transmitter, the maximum water level measurement value of the liquid level transmitter and the minimum water level measurement value of the liquid level transmitter are obtained, and it is determined whether the difference between the maximum water level measurement value of the liquid level transmitter and the minimum water level measurement value of the liquid level transmitter is greater than the second threshold value. If the judgment result is yes, a water level deviation alarm signal is generated to perform a water level deviation alarm. If the judgment result is no, no water level deviation alarm signal is generated and no water level deviation alarm is performed.

[0047] At the same time, a determination is made as to whether the difference between the two liquid level transmitters is greater than a third threshold. If so, a water level deviation alarm signal is generated to issue a water level deviation alarm. If not, no water level deviation alarm signal is generated, and no water level deviation alarm is issued. The difference between the two liquid level transmitters refers to the difference between the water level measurement value of the first liquid level transmitter and the water level measurement value of the second liquid level transmitter, the difference between the water level measurement value of the first liquid level transmitter and the water level measurement value of the third liquid level transmitter, and the difference between the water level measurement value of the second liquid level transmitter and the water level measurement value of the third liquid level transmitter.

[0048] S42, generating a water level sensor fault alarm signal according to the measured values ​​of each liquid level transmitter to perform a water level sensor fault alarm; Determine whether the water level measurement value of the first liquid level transmitter, the water level measurement value of the second liquid level transmitter and the water level measurement value of the third liquid level transmitter are within the measurement range respectively. If the judgment result is no, it means that the water level measurement value of a certain liquid level transmitter is abnormal, or the water level measurement values ​​of the three transmitters are inconsistent, and the liquid level transmitter fails. Then, a water level sensor fault alarm signal is generated to issue a water level sensor fault alarm; if the judgment result is yes, it means that the water level measurement value of a certain liquid level transmitter is a normal measurement value, then no water level sensor fault alarm signal is generated and no water level sensor fault alarm is issued.

[0049] S43. Generate an abnormal water level change alarm signal based on the measured values ​​of each liquid level transmitter to issue an abnormal water level change alarm.

[0050] Based on the water level measurement values ​​of each liquid level transmitter in the current cycle of a certain liquid level transmitter, it is judged whether the difference between the water level measurement value of the liquid level transmitter in the current cycle of the certain liquid level transmitter and the water level measurement value of the liquid level transmitter in the previous cycle is greater than the fourth threshold value. If the judgment result is yes, it means that the water level measurement value of the certain liquid level transmitter has risen or fallen rapidly in the current cycle, and an abnormal water level change has occurred. Then, an abnormal water level change alarm signal is generated to alarm the abnormal water level change; if the judgment result is no, no abnormal water level change alarm signal is generated, and no abnormal water level change alarm is issued.

[0051] At the same time, based on the water level measurement value of the liquid level transmitter at the current moment of a certain liquid level transmitter, it is judged whether the difference between the water level measurement value of the liquid level transmitter at the current moment of a certain liquid level transmitter and the water level measurement value of the liquid level transmitter at the previous moment is greater than the fifth threshold value. If the judgment result is yes, it means that the fluctuation amplitude of the water level measurement value of the certain liquid level transmitter at a certain moment is too large, and an abnormal water level change occurs, then an abnormal water level change alarm signal is generated to alarm the abnormal water level change; if the judgment result is no, no abnormal water level change alarm signal is generated, and no abnormal water level change alarm is performed.

[0052] The second water level alarm is performed through three liquid level transmitters, and one liquid level transmitter does not participate in the start and stop control of the drainage pump and is directly used for water level alarm, realizing multiple monitoring alarms. When the first water level alarm fails, the second water level alarm can be used in time to alarm, thereby improving the redundancy and reliability of the top cover water level monitoring.

[0053] The present invention also relates to a water level monitoring system for a hydro-generator top cover, which is used in the above-mentioned water level monitoring method for a hydro-generator top cover, such as Figure 2 Shown, including: A data acquisition module is used to collect water level information of the float switch, the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter; a liquid level transmitter measurement value acquisition module, configured to respectively verify the correctness of the measurement values ​​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 first liquid level transmitter measurement value, the second liquid level transmitter measurement value, and the third liquid level transmitter measurement value respectively through a median filtering method; The drainage pump start-stop control module is used to determine whether the float switch has passed the logic correctness test of each float ball action based on the float switch water level information. If the judgment result is no, the drainage pump is started and stopped according to the measurement values ​​of the first liquid level transmitter and the second liquid level transmitter. If the judgment result is yes, the float switch water level switch value is obtained. Based on the float switch water level switch value, the first liquid level transmitter measurement value and the second liquid level transmitter measurement value, 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 are selected to start and stop the drainage pump; a first water level alarm module, configured 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 according to the first water level alarm signal, wherein 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; The second water level alarm module is used to generate water level deviation alarm signals, water level sensor failure alarm signals and water level abnormal change alarm signals according to the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter, and to perform water level deviation alarms, water level sensor failure alarms and water level abnormal change alarms based on the water level deviation alarm signals, the water level sensor failure alarm signals and the water level abnormal change alarm signals.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for monitoring the water level of a hydro-generator top cover, characterized in that: The following steps are involved: S1. Obtaining water level information of the float switch, the first liquid level transmitter, and the second liquid level transmitter; S2. After performing a correctness check on the measured values ​​of the first liquid level transmitter and the second liquid level transmitter based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter, respectively, obtaining the measured values ​​of the first liquid level transmitter and the second liquid level transmitter respectively by using a median filtering method; S3. Determine whether the float switch passes the logic correctness test of each float action based on the float switch water level information. If the judgment result is no, perform start and stop control of the drainage pump based on the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter. If the judgment result is yes, obtain the water level switch value of the float switch. Based on the water level switch value of the float switch, the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter, select the water level switch value of the float switch and the measurement value of the first liquid level transmitter or the water level switch value of the float switch and the measurement value of the second liquid level transmitter to perform start and stop control of the drainage pump.

2. A method for monitoring the water level of a hydro-generator top cover according to claim 1, characterized in that: The method of 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 start and stop the drainage pump includes: Determine whether the difference between the measured value of the first liquid level transmitter and the measured value of the second liquid level transmitter is less than or equal to the deviation set value. If the judgment result is not, start and stop control of the drainage pump is performed based on the water level switch value of the float switch and the measured value of the first liquid level transmitter; If the judgment result is yes, then determine whether the water level switch value of the float switch is equal to the measurement value of the first liquid level transmitter. If the judgment result is no, then control the start and stop of the drainage pump based on the water level switch value of the float switch and the measurement value of the first liquid level transmitter. If the judgment result is yes, then control the start and stop of the drainage pump based on the water level switch value of the float switch and the measurement value of the second liquid level transmitter.

3. A method for monitoring the water level of a hydro-generator top cover according to claim 2, characterized in that: The start and stop control of the drainage pump based on the water level switch value of the float switch and the measured value of the first liquid level transmitter includes: respectively judging whether the water level value of the float switch and the measured value of the first liquid level transmitter have reached the pump start setting value; if the judgment result shows that the water level value of the float switch has reached the pump start setting value, then controlling the drainage pump to start drainage according to the water level value of the float switch; after the drainage pump has drained water, judging whether the water level value of the float switch has reached the pump stop setting value; if the judgment result is yes, then controlling the drainage pump to stop working; if the judgment result is no, then controlling the drainage pump to continue drainage; If the judgment result is that the measured value of the first liquid level transmitter reaches the pump start setting value, the drainage pump is controlled to start and drain water based on the measured value of the first liquid level transmitter; after the drainage pump drains water, it is judged whether the measured value of the first liquid 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.

4. The method for monitoring the water level of a hydro-generator top cover according to claim 1, characterized in that: The method of judging whether the float switch passes the logic correctness test of each float action according to the water level information of the float switch includes: The float switch water level information includes the water level float signal of stopping the pump, the water level float signal of starting the main pump, the water level float signal of starting the first standby pump, the water level float signal of starting the second standby pump and the high water level alarm float signal; Based on the water level from low to high, determine whether the water level information of the float switch is, in sequence, 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. If the judgment result is yes, the float switch passes the logic correctness test of each float action; if the judgment result is no, the float switch fails the logic correctness test of each float action.

5. The method for monitoring the water level of a hydro-generator top cover according to claim 1, characterized in that: The checking of the correctness of the measured values ​​of the first liquid level transmitter and the second liquid level transmitter based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter respectively includes: Based on the water level information of the first liquid level transmitter and the water level information of the second liquid level transmitter, the upper and lower limit 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 liquid level transmitter and the second liquid level transmitter respectively.

6. The method for monitoring the water level of a hydro-generator cover according to claim 1, characterized in that: The method further includes a second water level alarm step, wherein the second water level alarm step includes: Based on the measurement value of the first liquid level transmitter, the measurement value of the second liquid level transmitter and the obtained measurement value of the third liquid level transmitter, a water level deviation alarm signal, a water level sensor failure alarm signal and a water level abnormal change alarm signal are generated respectively; and according to the water level deviation alarm signal, the water level sensor failure alarm signal and the water level abnormal change alarm signal, a water level deviation alarm, a water level sensor failure alarm and a water level abnormal change alarm are respectively performed.

7. A method for monitoring the water level of a hydro-generator top cover according to claim 6, characterized in that: The obtained third liquid level transmitter measurement value includes: The water level information of the third liquid level transmitter is obtained, and after the correctness of the measured value of the third liquid level transmitter is checked according to the water level information of the third liquid level transmitter, the measured value of the third liquid level transmitter is obtained by using a median filtering method.

8. A method for monitoring the water level of a hydro-generator top cover according to claim 7, characterized in that: The correctness test of the measured value of the third liquid level transmitter includes: According to the water level information of the third liquid level transmitter, the upper and lower limit tests of the third liquid level transmitter, the jump test of the measured values ​​before and after the cycle, and the test of no change of the measured value within the cumulative cycle are respectively performed.

9. A water level monitoring system for a hydro-generator top cover, characterized in that: include: A data acquisition module is used to collect water level information of the float switch, the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter; a liquid level transmitter measurement value acquisition module, configured to respectively verify the correctness of the measurement values ​​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 first liquid level transmitter measurement value, the second liquid level transmitter measurement value, and the third liquid level transmitter measurement value respectively through a median filtering method; The drainage pump start-stop control module is used to determine whether the float switch has passed the logic correctness test of each float action based on the float switch water level information. If the judgment result is no, the drainage pump start-stop control is performed according to the measurement value of the first liquid level transmitter and the measurement value of the second liquid level transmitter; if the judgment result is yes, the float switch water level switch value is obtained, and based on the float switch water level switch value, the first liquid level transmitter measurement value and the second liquid level transmitter measurement value, 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 are selected to perform the drainage pump start-stop control.

10. The water level monitoring system for the top cover of a hydro-generator set according to claim 9, 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 failure alarm signal and a water level abnormal change alarm signal according to the measurement values ​​of the first liquid level transmitter, the second liquid level transmitter and the third liquid level transmitter, and to issue a water level deviation alarm, a water level sensor failure alarm and a water level abnormal change alarm based on the water level deviation alarm signal, the water level sensor failure alarm signal and the water level abnormal change alarm signal.

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