A method for detecting efficiency of a hydroelectric generating unit

Abstract

The application relates to the technical field of hydropower unit detection methods, and discloses a hydropower unit efficiency detection method, which comprises the following steps: step one: acquiring basic data for efficiency detection, the installation elevation (h1, h2) of the hydropower unit equipment, wherein h1 is the center elevation of the installation position of a meter at a volute pressure measuring point, h2 is the center elevation of the installation position of a meter at a tail water pressure measuring point, and the latitude of the installation position of the unit; the hydropower unit efficiency detection method can output the calculation efficiency and the calculation error in real time, provides data support for real-time trend analysis and historical trend analysis of the operation efficiency of the hydropower unit, and is convenient for technicians to monitor and analyze the operation efficiency of the unit under various working conditions; the detection method is combined with a remote real-time online monitoring and analysis system, real-time acquisition data and historical storage data are closely matched, various working conditions in the actual operation process of the hydropower unit can be covered, and the input parameter conditions are optimized to facilitate the determination of the operation efficiency of the hydropower unit.

Description

Technical Field

[0001] This invention relates to the technical field of hydropower unit testing methods, specifically to a method for testing the efficiency of hydropower units. Background Technology

[0002] Small hydropower can not only improve the energy structure and increase energy supply, but also protect the ecological environment and reduce greenhouse gas emissions. However, the output characteristics of small hydropower are closely related to the amount of power generation and fluctuate greatly, especially for run-of-river small hydropower stations. Current small hydropower stations are usually composed of several small-capacity generators, and even the capacity of each generator is not exactly the same. Their operating efficiency varies with the output of the generators. When the total power generation of a small hydropower station is constant, it is desirable to maximize the total output of all generators in the small hydropower station. That is, it is necessary to reasonably allocate the power generation among the units of the small hydropower station to optimize the operating efficiency of the generators in the station. This requires the optimization of the allocation scheme by detecting the operating efficiency of the hydropower units of small hydropower stations. This scheme specifically involves a method for detecting the efficiency of hydropower units.

[0003] However, existing methods for detecting the efficiency of hydropower units cannot output the calculated efficiency and calculation error in real time. The data support for real-time trend analysis and historical trend analysis of the operating efficiency of hydropower units is insufficient, making it difficult for technicians to monitor and analyze the operating efficiency of the turbine under various operating conditions. It is also impossible to closely integrate real-time collected data with historical stored data, and it cannot cover various operating conditions in the actual operation of hydropower units, which is not conducive to determining the operating efficiency of hydropower units. Summary of the Invention

[0004] The main objective of this invention is to provide a method for detecting the efficiency of hydropower units, which can effectively solve the problems mentioned in the background art, such as the inability to output calculated efficiency and calculation errors in real time, insufficient support from real-time trend analysis and historical trend analysis of hydropower unit operating efficiency, difficulty for technicians to monitor and analyze the operating efficiency of the turbine under various operating conditions, inability to closely coordinate real-time collected data with historical stored data, inability to cover various operating conditions in the actual operation of hydropower units, and difficulty in determining the operating efficiency of hydropower units.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for testing the efficiency of a hydropower unit includes the following steps:

[0007] Step 1: Obtain basic data for efficiency testing, including the turbine unit equipment installation elevation (h1, h2), where h1 is the center elevation of the meter installation location at the spiral casing pressure test point, h2 is the center elevation of the meter installation location at the tailrace pressure test point, and the latitude of the unit installation location. The cross-sectional area s1 of the pipe at the inlet pressure test point of the unit's spiral casing, and the cross-sectional area s2 of the pipe at the outlet pressure test point of the unit's tailwater pipe.

[0008] Step 2: Design a data storage history database to obtain the sample data required for online calculation. Through the access interfaces of the real-time database and the history database, design a custom relational table for vibration-related data in the form of an extended plug-in application. Periodically store the raw data of monitoring point active power, unit flow rate, volute inlet pressure, tailrace outlet pressure, guide vane opening, unit frequency, upstream water level, downstream water level, power factor, water temperature and other data obtained from the real-time database into the custom data table.

[0009] Step 3: Sample parameter acquisition and calculation process. The absolute pressure values ​​of the volute and tailwater, the water density at the volute and tailwater, and the working head sample parameters are calculated to obtain the unit flow parameters and unit power parameters.

[0010] Step 4: Determine the validity of the sample data. The accuracy of the efficiency calculation process depends on the validity of the sample data acquisition process. The primary condition is to determine whether the unit's operating conditions are stable. The criteria for determination depend on whether there are significant fluctuations in parameters such as the unit's active power, operating head, and rotational speed.

[0011] Step 5: Calculation Results and Error Analysis. In the process of calculating turbine efficiency, various sample data need to be acquired. These sample data include direct measurement data and indirect measurement data. Indirect measurement data is obtained indirectly from multiple direct measurement data through a certain functional relationship. Due to limitations in measurement methods, instruments, and other tools, the direct measurement data acquired by the hydropower unit's data acquisition and monitoring control system generally contains errors. These errors will be reflected in the indirect measurement data. Without providing the reliability of the sample parameter acquisition results, the quality of the measurement results cannot be fully reflected. Therefore, the errors of each direct measurement quantity are analyzed, and the errors of the indirect measurement quantities are derived.

[0012] Preferably, in step three, the absolute pressure of the volute and tailwater is calculated using the formula p = p1 + p0(h0 - h1 / 900) / h0, where p is the absolute pressure, p1 is the gauge pressure, p0 is the standard atmospheric pressure, h0 is the water column under standard atmospheric pressure, and h1 is the center elevation of the pressure gauge installation location.

[0013] Preferably, in step three, the formulas for calculating the water density ρ1 at the volute, the water density ρ2 at the tailwater, and the average water density ρ are ρ1=ρ0+k(p wk / 100-10) / 10, ρ2=ρ0+k(p ws / 100-10) / 10, ρ=(ρ1+ρ2) / 2, where: p wk and p wsρ0 represents the absolute pressure at the volute and tailwater outlet, respectively; k is the density calculation baseline value; and ρ0 is the density calculation correction factor.

[0014] Preferably, the calculation formula for obtaining the working head is as follows: In the formula: Let p1 be the average pressure at the volute inlet, p2 be the average pressure at the tailrace inlet, and q be the acceleration due to gravity. m This refers to the unit's flow rate.

[0015] Preferably, the process of acquiring the unit flow parameters uses an ultrasonic flow meter. Considering the large diameter of the turbine inlet steel pipe, a multi-channel flow measurement method is used in the measurement, and a cross-path arrangement is adopted. The two sound paths at the same elevation are installed at opposite angles to improve the measurement accuracy. The accuracy of the flow meter acquisition directly affects the accuracy of the efficiency calculation results.

[0016] Preferably, in the process of obtaining the unit power parameters, the active power output by the generator is the output power of the hydraulic unit, which is one of the important data for calculating the efficiency of the hydraulic unit. The accuracy of its measurement depends on the measurement method and the precision of the measuring instruments used. Since the hydro-generator has a large capacity and high voltage, when performing three-phase active power measurement, the power meter cannot be directly connected to the bus, but the three-phase power is measured through voltage transformers and current transformers.

[0017] Preferably, the specific judgment criteria in step four are as follows: the difference in the active power of the unit within 10 minutes should not exceed ±1.5% of the average active power of the unit within that period, i.e., (peak active power / 2) / average active power, and the ratio of active power change should be ≤ ±1.5%; the change in hydraulic specific energy within 10 minutes should not exceed ±1.0% of the average value, i.e., (unit working head - unit average working head) / unit average working head, and the ratio of hydraulic specific energy change should be ≤ ±1.0%; the change in unit speed within 10 minutes should not exceed ±0.5% of the average value, i.e., (peak unit frequency / 2) / average unit frequency, and the ratio of speed change should be ≤ ±0.5%.

[0018] Preferably, the error analysis method employs the function increment method, assuming that the input parameters are directly measurable quantities (x1, x2, ..., x...). n If the standard error of y is (δx1, δx2, ..., δxx), then the error of each directly measured quantity causes an error δy in the indirectly measured quantity y. i + =f(x1+δx1,x2+δx2,…,x i +δx i , ..., x n +δx n )-f(x1, x2, ..., xi , ..., x n ) or δy i - =f(x1-δx1,x2-δx2,…,x i -δx i , ..., x n -δx n )-f(x1, x2, ..., x i , ..., x n ), the average value of the absolute value of the error δx i The standard error δy caused by y i =(|δy i + |+|δy i - |) / 2, since each directly measured quantity is independent of the others, the total standard error of the indirect measured quantity y is...

[0019] Preferably, during the process of calculating the efficiency of the water turbine, whether the calculation results meet the application requirements and whether they are reliable can be directly determined by error indicators. At the same time, data that meet the error indicators can be extracted for subsequent application analysis.

[0020] Preferably, the analysis method relies on a remote real-time online monitoring and analysis system, which closely integrates real-time collected data with historical stored data. The required data can cover various operating conditions in the actual operation of the turbine, optimizing the judgment of input parameter conditions and the error analysis of output results.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention enables intelligent online monitoring and analysis, and can output the calculation efficiency and calculation error in real time during the detection process of hydropower units. It provides data support for real-time trend analysis and historical trend analysis of the operating efficiency of hydropower units, making it easier for technicians to monitor and analyze the operating efficiency of the turbine under various operating conditions.

[0023] Furthermore, by combining the detection method with a remote real-time online monitoring and analysis system, and by closely coordinating real-time data acquisition with historical data storage, it is possible to cover various operating conditions in the actual operation of hydropower units, and optimize input parameter conditions to facilitate the determination of hydropower unit operating efficiency. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for detecting the efficiency of a hydropower unit according to the present invention;

[0025] Figure 2 This is a flowchart illustrating the sample parameter acquisition process of a hydropower unit efficiency testing method according to the present invention. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0028] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Example

[0033] like Figure 1-2 As shown, a method for detecting the efficiency of a hydropower unit includes the following steps:

[0034] Step 1: Obtain basic data for efficiency testing, including the turbine unit equipment installation elevation (h1, h2), where h1 is the center elevation of the meter installation location at the spiral casing pressure test point, h2 is the center elevation of the meter installation location at the tailrace pressure test point, and the latitude of the unit installation location. The cross-sectional area s1 of the pipe at the inlet pressure test point of the unit's spiral casing, and the cross-sectional area s2 of the pipe at the outlet pressure test point of the unit's tailwater pipe.

[0035] Step 2: Design a data storage history database to obtain the sample data required for online calculation. Through the access interfaces of the real-time database and the history database, design a custom relational table for vibration-related data in the form of an extended plug-in application. Periodically store the raw data of monitoring point active power, unit flow rate, volute inlet pressure, tailrace outlet pressure, guide vane opening, unit frequency, upstream water level, downstream water level, power factor, water temperature and other data obtained from the real-time database into the custom data table.

[0036] Step 3: Sample parameter acquisition and calculation process. The absolute pressure values ​​of the volute and tailwater, the water density at the volute and tailwater, and the working head sample parameters are calculated to obtain the unit flow parameters and unit power parameters.

[0037] Step 4: Determine the validity of the sample data. The accuracy of the efficiency calculation process depends on the validity of the sample data acquisition process. The primary condition is to determine whether the unit's operating conditions are stable. The criteria for determination depend on whether there are significant fluctuations in parameters such as the unit's active power, operating head, and rotational speed.

[0038] Step 5: Calculation Results and Error Analysis. In the process of calculating turbine efficiency, various sample data need to be acquired. These sample data include direct measurement data and indirect measurement data. Indirect measurement data is obtained indirectly from multiple direct measurement data through a certain functional relationship. Due to limitations in measurement methods, instruments, and other tools, the direct measurement data acquired by the hydropower unit's data acquisition and monitoring control system generally contains errors. These errors will be reflected in the indirect measurement data. Without providing the reliability of the sample parameter acquisition results, the quality of the measurement results cannot be fully reflected. Therefore, the errors of each direct measurement quantity are analyzed, and the errors of the indirect measurement quantities are derived.

[0039] The formula for calculating the absolute pressure of the volute and tailwater in step three is as follows:

[0040] p = p1 + p0(h0 - h1 / 900) / h0

[0041] In the formula: p is the absolute pressure, p1 is the gauge pressure, p0 is the standard atmospheric pressure, h0 is the water column under standard atmospheric pressure, and h1 is the center elevation of the pressure gauge installation position.

[0042] The formulas for calculating the water density ρ1 at the volute, the water density ρ2 at the tailwater, and the average water density ρ in step three are as follows:

[0043] ρ1=ρ0+k(p wk / 100-10) / 10, ρ2=ρ0+k(p ws / 100-10) / 10,ρ=(ρ1+ρ2) / 2

[0044] In the formula: p wk and p ws ρ0 represents the absolute pressure at the volute and tailwater outlet, respectively; k is the density calculation baseline value; and ρ0 is the density calculation correction factor.

[0045] The formula for calculating the working head is:

[0046]

[0047] In the formula: Let p1 be the average pressure at the volute inlet, p2 be the average pressure at the tailrace inlet, and q be the acceleration due to gravity. m This refers to the unit's flow rate.

[0048] The process of acquiring the unit's flow parameters uses an ultrasonic flow meter. Considering the large diameter of the turbine's inlet steel pipe, a multi-channel flow measurement method is used in the measurement. A cross-path arrangement is adopted, with two sound paths at the same elevation installed at opposite angles to improve measurement accuracy. The accuracy of the flow meter's acquisition directly affects the accuracy of the efficiency calculation results.

[0049] In the process of obtaining the power parameters of the unit, the active power output by the generator is the output power of the hydraulic unit, which is one of the important data for calculating the efficiency of the hydraulic unit. The accuracy of its measurement depends on the measurement method and the precision of the measuring instruments used. Since the hydro-generator has a large capacity and high voltage, when performing three-phase active power measurement, the power meter cannot be directly connected to the bus. Instead, the three-phase power is measured through voltage transformers and current transformers.

[0050] The specific judgment criteria in step four are as follows: the difference in the active power of the unit within 10 minutes shall not exceed ±1.5% of the average active power of the unit within that period, i.e., (peak active power / 2) / average active power, and the ratio of active power change should be ≤ ±1.5%; the change in hydraulic specific energy within 10 minutes shall not exceed ±1.0% of the average value, i.e., (unit working head - unit average working head) / unit average working head, and the ratio of hydraulic specific energy change should be ≤ ±1.0%; the change in unit speed within 10 minutes shall not exceed ±0.5% of the average value, i.e., (peak unit frequency / 2) / average unit frequency, and the ratio of speed change should be ≤ ±0.5%.

[0051] The error analysis method uses the function increment method, assuming that the input parameters are directly measurable quantities (x1, x2, ..., x...). n The standard error of is (δx1, δx2, ..., δx) n If the error of each directly measured quantity causes an error δy in the indirectly measured quantity y, then the error of each directly measured quantity y will cause an error δy in the indirectly measured quantity y. i + =f(x1+δx1,x2+δx2,…,xi+δx i , ..., x n +δx n )-f(x1, x2, ..., x i , ..., x n ) or δy i - =f(x1-δx1,x2-δx2,…,x i -δx i , ..., x n -δx n )-f(x1, x2, ..., x i , ..., x n ), the average value of the absolute value of the error δx i The standard error δy caused by y i =(|δy i + |+|δy i - |) / 2, since each directly measured quantity is independent of the others, the total standard error of the indirect measured quantity y is...

[0052] In the process of calculating the efficiency of a water turbine, whether the calculation results meet the requirements of the application and whether they are reliable can be directly judged by the error index. At the same time, data that meet the requirements of the error index can be extracted for subsequent application analysis.

[0053] In this embodiment, the analysis method relies on a remote real-time online monitoring and analysis system, which closely combines real-time collected data with historical stored data. The required data can cover various operating conditions in the actual operation of the turbine, optimizing the judgment of input parameter conditions and the error analysis of output results.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting the efficiency of a hydropower unit, characterized in that: Includes the following steps: Step 1: Query and obtain basic data for efficiency testing, including the center elevation of the pressure gauge installation location at the spiral casing of the turbine unit. The center elevation of the pressure gauge installation location at the tailwater pressure test point The latitude of the unit's installation location The cross-sectional area of ​​the pipe at the pressure testing point of the unit's volute inlet. Cross-sectional area of ​​the pressure test point at the outlet pipe of the unit's tailwater pipe ; Step 2: Design a data storage history database, obtain the sample data required for online calculation, and design a custom relational table for vibration-related data through the access interface of the real-time database and the historical database in the form of an extended plug-in application. Periodically store the data information of active power, unit flow, volute inlet pressure, tailrace outlet pressure, guide vane opening, unit frequency, upstream water level, downstream water level, power factor, and water temperature obtained from the real-time database into the custom data table as raw data. Step 3: Sample parameter acquisition and calculation process. The absolute pressure values ​​of the volute and tailwater, the water density at the volute and tailwater, and the working head sample parameters are calculated to obtain the unit flow parameters and unit power parameters. The formula for calculating the absolute value of the volute pressure in step three. In the formula: For absolute pressure, For measuring pressure, Standard atmospheric pressure The water column at standard atmospheric pressure. The elevation of the center of the meter installation location at the volute pressure measurement point; Water density at the volute in step three Water density at the tailrace Average water density The calculation formula is , , In the formula: and These are the absolute pressures at the volute and tailrace outlet, respectively. As a baseline value for density calculation, Calculate the correction factor for density; Step 4: Determine the validity of the sample data. The accuracy of the efficiency calculation process depends on the validity of the sample data acquisition process. The primary condition is to determine whether the unit's operating conditions are stable. The criteria for determination depend on whether there are significant fluctuations in the parameters of the unit's active power, operating head, and rotational speed. Step 5: Calculation Results and Error Analysis. In the process of calculating turbine efficiency, various sample data need to be obtained. These sample data include direct measurement data and indirect measurement data. Indirect measurement data is obtained indirectly from multiple direct measurement data through a certain functional relationship. Due to limitations in measurement methods, instruments, and related tools, the direct measurement data acquired by the hydropower unit's data acquisition and monitoring control system generally contains errors. These errors will be reflected in the indirect measurement data. Without providing the reliability of the sample parameter acquisition results, the quality of the measurement results cannot be fully reflected. Therefore, the errors of each direct measurement quantity are analyzed, and the errors of the indirect measurement quantities are derived. The error analysis method adopts the function increment method, assuming that the input parameters are directly measurable quantities. The standard error is Then the error of each directly measured quantity causes the error of the indirect measured quantity y. and Take the average of the absolute values ​​of the errors. The standard error of y Since the direct measurements are independent of each other, the total standard error of the indirect measurement y is... .

2. The method for detecting the efficiency of a hydropower unit according to claim 1, characterized in that: The process of acquiring the unit's flow parameters uses an ultrasonic flow meter. Considering the large diameter of the turbine's inlet steel pipe, a multi-channel flow measurement method is used in the measurement. A cross-path arrangement is adopted, with two sound paths at the same elevation installed at opposite angles to improve measurement accuracy. The accuracy of the flow meter's acquisition directly affects the accuracy of the efficiency calculation results.

3. The method for detecting the efficiency of a hydropower unit according to claim 1, characterized in that: In the process of obtaining the power parameters of the unit, the active power output by the generator is the output power of the hydraulic unit, which is one of the important data for calculating the efficiency of the hydraulic unit. The accuracy of its measurement depends on the measurement method and the precision of the measuring instruments used. Since the hydro-generator has a large capacity and high voltage, when performing three-phase active power measurement, the power meter cannot be directly connected to the bus. Instead, the three-phase power is measured through voltage transformers and current transformers.

4. The method for detecting the efficiency of a hydropower unit according to claim 1, characterized in that: The specific judgment criteria in step four are as follows: the difference in active power of the unit within 10 minutes shall not exceed ±1.5% of the average active power of the unit within that period, i.e., (peak active power / 2) / average active power, and the ratio of active power change should be ≤ ±1.5%; the change in hydraulic specific energy within 10 minutes shall not exceed ±1.0% of the average value, i.e., (unit working head - unit average working head) / unit average working head, and the ratio of hydraulic specific energy change should be ≤ ±1.0%; the change in unit speed within 10 minutes shall not exceed ±0.5% of the average value, i.e., (peak unit frequency / 2) / average unit frequency, and the ratio of speed change should be ≤ ±0.5%.

5. The method for detecting the efficiency of a hydropower unit according to claim 1, characterized in that: In the process of calculating the efficiency of a water turbine, whether the calculation results meet the application requirements and are reliable can be directly determined by the error index. At the same time, data that meet the error index requirements can be extracted for subsequent application analysis.

6. The method for detecting the efficiency of a hydropower unit according to claim 1, characterized in that: The error analysis method relies on a remote real-time online monitoring and analysis system, which closely integrates real-time collected data with historical stored data. The required data can cover various operating conditions in the actual operation of the turbine, optimizing the judgment of input parameter conditions and the error analysis of output results.

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