Online extraction method for power characteristic curve of guide vane of hydroelectric generating set

Abstract

The invention discloses an online extraction method for a guide vane power characteristic curve of a hydroelectric generating set, and the method comprises the following steps: obtaining water head data, hydroelectric generating set operation state monitoring data and power generation plan data, and forming a parameter database; for any hydroelectric generating set, after the grid connection moment, extracting time sequence data of the hydroelectric generating set within continuous 10 seconds when the opening degree of the guide vane is not changed from the parameter database, and generating an initial power characteristic point serving as a power characteristic curve of the guide vane of the hydroelectric generating set based on the time sequence data; after the active power target value of the hydroelectric generating set is completed every time, time sequence data within continuous 10 seconds after completion are extracted from a parameter database, and a plurality of other power characteristic points are formed; sequencing according to the opening degrees of the guide vanes and calculating the integrity of the power characteristic curve of the guide vanes; and performing five-order polynomial curve fitting on the power characteristic points of which the completeness of the guide vane power characteristic curve is greater than 90% to form the power characteristic curve of the guide vane of the hydroelectric generating set.

Description

Technical Field

[0001] The invention relates to the technical field of hydropower unit regulation, and in particular to an online extraction method for a guide vane power characteristic curve of a hydropower unit. Background Art

[0002] There are many large hydropower plants distributed in the southwest of my country. As the scale of installed capacity of new energy sources continues to grow, the peak-shaving and frequency-regulating effects of these large hydropower plants will become increasingly important. The fast and disturbance-free automatic power generation control capabilities of large hydropower units are conducive to smoothing the fluctuations in the output of new energy sources such as wind power and photovoltaics, and stabilizing the frequency of the power grid. When the system frequency or the power demand of the power grid changes, the dispatching AGC master station sends the dispatching AGC set value to the hydropower plant AGC substation through the telecontrol transmission channel, and the hydropower plant AGC substation controls the total power of the entire plant to achieve a correct response to the dispatching AGC set value. After the plant-wide AGC server or AGC control device receives the AGC set value issued by the dispatch, the plant-wide AGC server sends the unit AGC distribution value to each unit that has been put into single-machine AGC; the unit LCU realizes closed-loop control of the unit's active power. The block diagram of the unit's active power control in the opening mode is as follows: Figure 1 shown.

[0003] The grid dispatching agency requires hydropower plants to invest in AGC functions and has clear regulations on the AGC response time, regulation rate, and regulation accuracy indicators. However, the AGC regulation rate and regulation accuracy of hydropower plants are greatly affected by the actual power generation head, making it difficult for the AGC regulation pass rate to meet the dispatching agency's requirements. Under different head heights, there are large differences in the characteristic curves of the relationship between the output of the hydropower unit and the guide vane opening of the unit, resulting in the regulation performance of the hydropower unit being greatly affected by the actual head height during actual operation. When the head is high, the AGC regulation rate is fast, which is prone to large overshoot and poor regulation accuracy; when the head is low, the AGC regulation rate is slow, the overshoot is small, and the regulation accuracy is high.

[0004] There is an obvious nonlinear characteristic between the output of the hydropower unit and the guide vane opening. The guide vane power characteristic curves of the unit under different water heads are obviously different, such as Figure 2 As shown in the figure, the power increment corresponding to the unit guide vane increment at different load sections and different head heights is significantly different, which makes the AGC adjustment rate vary greatly. The rich guide vane power characteristic data is of practical significance for setting the unit active control parameters and optimizing the unit operation.

[0005] At present, the test method is used to measure the guide vane-power characteristic data of the unit. During the test, the whole plant AGC and the unit AGC need to be shut down, and the remote dispatch needs to coordinate and adjust the power generation plan. During the test, the unit active setting value is manually modified continuously, resulting in drastic changes in the output of the whole plant, which is not conducive to the frequency stability of the power grid system. Therefore, the power plant only has the guide vane-power characteristic data of the unit under a small amount of water head.

[0006] In view of this, this application is hereby filed. Summary of the invention

[0007] In view of the above-mentioned prior art, the present invention provides an online extraction method for the power characteristic curve of the guide vane of a hydropower unit, mainly to solve the technical problems existing in the above-mentioned background technology.

[0008] To achieve the above object, the technical solution of the embodiment of the present invention is implemented as follows:

[0009] An online extraction method for a guide vane power characteristic curve of a hydropower unit, the method comprising the following steps:

[0010] Obtain water head data, hydropower unit operation status monitoring data, power generation plan data, and form a parameter database;

[0011] For any hydropower unit, after the grid connection time, the time series data of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change is extracted from the parameter database, and the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit is generated based on the time series data;

[0012] After each adjustment of the active power target value of the hydropower unit is completed according to the AGC instruction of the whole plant, the time series data within 10 seconds after the completion is extracted from the parameter database to form a plurality of other power characteristic points;

[0013] After disconnection or continuous operation for 24 hours, the upstream and downstream water level data are filtered by sliding average, the head change of the day is analyzed, and the guide vane opening is sorted and the integrity of the guide vane power characteristic curve is calculated;

[0014] A fifth-order polynomial curve fitting is performed on the power characteristic points of the guide vane power characteristic curve whose integrity is greater than 90% to form the guide vane power characteristic curve of the hydropower unit.

[0015] Preferably, the time series data includes guide vane opening, unit active power, and water head height.

[0016] Preferably, generating the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit specifically includes: respectively obtaining the mean of the guide vane opening, the unit active power, and the gross head data in the time series data of the period as the starting point of the guide vane power characteristic curve of the hydropower unit, recorded as (y ctg_x , P ctg_x , H ctg_x ), where y ctg_x is the average guide vane opening of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change, P ctg_x H is the average active power of the hydropower unit within 10 seconds when the guide vane opening does not change. ctg_xIt is the average water head height of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change.

[0017] Preferably, when the hydropower unit actually generates active power P act Enter the unit active power setting value P set When the active power target value of the hydropower unit is within the dead zone of ±0.01Pe, the adjustment is completed.

[0018] Preferably, a plurality of other power characteristic points are formed, specifically including: intercepting the time series data of the guide vane opening, active power of the unit, and upstream and downstream water heads of the unit for 10 consecutive seconds after the adjustment of the hydropower unit is completed, and respectively obtaining the mean of the guide vane opening, active power of the unit, and gross water head data in this section of the time series data as other discrete points of the guide vane power characteristic curve of the hydropower unit, recorded as (y k_x , P k_x , H k_x ), where y k_x P is the average guide vane opening of the hydropower unit within 10 seconds after the unit is regulated. k_x H is the average active power of the hydropower unit within 10 seconds after the adjustment is completed. k_x It is the average water head height within 10 seconds after the hydropower unit is adjusted.

[0019] Preferably, after the unit decoupling order is issued or the unit has been running continuously for 24 hours, the time series data of the upstream and downstream water levels of the power station are subjected to sliding average filtering, the degree of head change on that day is analyzed, and the guide vane power characteristic points located in the head range obtained from the start-up of the unit to the current moment are sorted from small to large according to the guide vane opening.

[0020] Preferably, the guide vane power characteristic curve integrity is calculated by the following formula:

[0021] D=(y max -y min ) / 100

[0022] where y max is the maximum guide vane opening within the water head range, y max It is the minimum value of the guide vane opening within the head range.

[0023] Preferably, if the completeness of the guide vane power characteristic curve in the head interval is greater than 90%, a fifth-order polynomial curve fitting is performed on all guide vane power characteristic points in the head interval, and the fitting curves formed by multiple head intervals constitute the guide vane-power characteristic curve.

[0024] The beneficial effects of the present invention are as follows: by extracting and analyzing the guide vane-power characteristic data of the hydropower unit online, the problem of insufficient data collection in the traditional test method is solved, the grid frequency fluctuation caused by the withdrawal of the whole plant AGC and the unit AGC is avoided, and the automation level and operation efficiency of the hydropower plant are significantly improved; by sorting the guide vane-power characteristic points obtained from the start-up of the unit to the current moment, and fitting the data with a completeness greater than 90% with a fifth-order polynomial, a more accurate guide vane-power characteristic curve is generated. This high-precision curve not only reflects the nonlinear characteristics of the unit under different head conditions, but also provides a scientific basis for optimizing control parameters. According to the fitted curve, the optimal guide vane opening can be quickly found to achieve the best power generation efficiency and response speed, while reducing unnecessary energy consumption and equipment wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the block diagram of the active power control of the unit in the opening mode;

[0026] Figure 2 The corresponding relationship between the unit output and the guide vane of the hydropower unit under different water heads;

[0027] Figure 3 A flow chart of an online extraction method of a guide vane power characteristic curve of a hydropower unit provided in an embodiment of the present application;

[0028] Figure 4 It is the flow diagram for extracting discrete points of the guide vane-power characteristic curve when the active power set value of the unit changes. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, the expression "some embodiments" is related to a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0030] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0031] It should be understood that the present invention can be implemented in different forms and should not be interpreted as being limited to the embodiments proposed herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and the scope of the present invention will be fully conveyed to those skilled in the art. And the purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present invention. When used herein, the singular forms of "one", "one" and "said / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "compose" and / or "include" when used in this specification determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "inside", "outside", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0033] In order to fully understand the present invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by the present invention. The optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0034] Please refer to the attached Figure 3 to Figure 4 , the present application provides a method for online extraction of the guide vane power characteristic curve of a hydropower unit, and a method for online extraction of the guide vane power characteristic curve of the unit under different water heads based on the real-time operation data of the unit. Obtain the active setting value, actual active value, guide vane feedback of the hydropower unit, and head signals of the upstream and downstream of the power plant. After each change in the active setting value, the active power of the unit is judged by the scanning method to enter the target range of the active setting value and the guide vane is no longer changing, and a guide vane-power discrete point is extracted. The degree of change of the water level upstream and downstream of the power plant is judged from the start-up to shutdown of the unit or 24 hours as a cycle. If the degree of change is less than the threshold, the guide vane-power discrete points in this cycle are merged into a guide vane-power characteristic table under one water head; the guide vane-power characteristic table is fitted by a polynomial fitting method to obtain a guide vane-power characteristic curve. The method specifically includes the following steps:

[0035] S1. Obtain water head data, hydropower unit operation status monitoring data, power generation plan data, and form a parameter database. This process is for parameter setting and data collection. The hydropower unit operation status monitoring data includes guide vane opening data. For other data, specifically, obtain today's power generation plan curve issued by the dispatcher, the planned value P of the whole plant at a certain moment sch , and consider the spinning reserve capacity P res Calculate the number of power plants in operation at each time n sch， n sch equal The symbol for rounding up.

[0036] For the water head data, the upstream and downstream water head measurement data from 00:00 to 23:59 of the previous day were obtained, and the upstream and downstream water head measurement signals were filtered using a sliding average filter. The upstream and downstream filtered data at the same time were subtracted to obtain the gross water head data from 00:00 to 23:59 of the previous day, and the water head change rate Δh within 1 hour was calculated hour by hour. 1h And the maximum change of water head yesterday

[0037]

[0038] Determine yesterday's water head amplitude Is it greater than Δhstep , if it is greater than, it means that the water head changes greatly within a day; if it is less than, it means that the water head changes less within a day. When the water head changes greatly within a day, the estimated water head change Δh step Required actual t = Δh step / Δh 1h .

[0039] In addition, during this process, it is also necessary to calculate the maximum variation between the highest head (Hmax) and the lowest head (Hmin) of the hydropower plant, and then divide this variation by the preset number of head segments M to obtain the change step size of each head segment. This step is to divide the head range into multiple discrete intervals to facilitate subsequent data collection and analysis.

[0040] The parameter database is built through the data generated by the above process.

[0041] S2. For any hydropower unit, after the grid-connected moment, extract the time series data of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change from the parameter database, and generate the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit based on the time series data, wherein the time series data includes the guide vane opening, the unit active power, and the water head height;

[0042] S3, after each adjustment of the active power target value of the hydropower unit is completed according to the AGC instruction of the whole plant, the time series data within 10 seconds after the completion is extracted from the parameter database to form a plurality of other power characteristic points;

[0043] S4. After decoupling or continuous operation for 24 hours, perform sliding average filtering on the upstream and downstream water level data, analyze the water head changes on that day, sort by guide vane opening and calculate the integrity of the guide vane power characteristic curve;

[0044] S5. Perform fifth-order polynomial curve fitting on the power characteristic points of the guide vane power characteristic curve whose integrity is greater than 90% to form the guide vane power characteristic curve of the hydropower unit.

[0045] In an optional embodiment, generating the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit specifically includes: obtaining the mean of the guide vane opening, the unit active power, and the gross head data in the time series data of the period respectively as the starting point of the guide vane power characteristic curve of the hydropower unit, recorded as (y ctg_x , P ctg_x , H ctg_x ), where y ctg_x is the average guide vane opening of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change, P ctg_x H is the average active power of the hydropower unit within 10 seconds when the guide vane opening does not change. ctg_x It is the average water head height of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change.

[0046] In an optional implementation, when the total active power command of the whole plant AGC changes, the whole plant AGC sends a new active power target value to unit X. After the active power target value of the unit changes, the guide vane opening of the unit changes to respond to the whole plant AGC command. When the hydropower unit actually generates active power P act Enter the unit active power setting value P set When the active power target value of the hydropower unit is within the dead zone of ±0.01Pe, the adjustment is completed.

[0047] In an optional embodiment, multiple other power characteristic points are formed, specifically including: intercepting the time series data of the guide vane opening, active power of the unit, and upstream and downstream water heads of the hydropower unit for 10 consecutive seconds after the adjustment is completed, and respectively obtaining the mean of the guide vane opening, active power of the unit, and gross water head data in this time series data as other discrete points of the guide vane power characteristic curve of the hydropower unit, recorded as (y k_x , P k_x , H k_x ), where y k_x P is the average guide vane opening of the hydropower unit within 10 seconds after the unit is regulated. k_xH is the average active power of the hydropower unit within 10 seconds after the adjustment is completed. k_x It is the average water head height within 10 seconds after the hydropower unit is adjusted.

[0048] Each time the unit active power target value changes, multiple other discrete points can be obtained.

[0049] In an optional implementation, after the unit decoupling order is issued or the unit has been running continuously for 24 hours, the upstream and downstream water levels of the power station are subjected to sliding average filtering, the degree of head change on the day is analyzed, and the water head interval [H] obtained from the start-up of the unit to the current moment is obtained. ctg_X ,H ctg_X + Δhstep ], sort the guide vane power characteristic points in the interval from small to large according to the guide vane opening, and count the number of discrete points in each interval. If the number of discrete points in a head interval is small, it means that the guide vane-power characteristic data of the interval is incomplete, and more loads need to be allocated to the units that have collected relatively complete guide vane-power characteristic data, so as to complete the construction of the entire curve as soon as possible. The completeness of the guide vane power characteristic curve can be calculated by the following formula:

[0050] D=(y max -y min ) / 100

[0051] where y max is the maximum guide vane opening within the water head range, y max It is the minimum value of the guide vane opening within the head range.

[0052] In an optional embodiment, if the completeness of the guide vane power characteristic curve in the water head interval is greater than 90%, a fifth-order polynomial curve fitting is performed on all guide vane power characteristic points in the water head interval, and the fitting curves formed by multiple water head intervals are used as the basis to form the hydropower generator unit in (H ctg_X + Δhstep ) / 2 guide vane-power characteristic curve under water head.

[0053] Finally, use the head height or date to query the power characteristic curve of the unit.

[0054] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An online extraction method for the power characteristic curve of the guide vane of a hydropower unit, characterized in that: The method comprises the following steps: Obtain water head data, hydropower unit operation status monitoring data, power generation plan data, and form a parameter database; For any hydropower unit, after the grid connection time, the time series data of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change is extracted from the parameter database, and the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit is generated based on the time series data; After each adjustment of the active power target value of the hydropower unit is completed according to the AGC instruction of the whole plant, the time series data within 10 seconds after the completion is extracted from the parameter database to form a plurality of other power characteristic points; After disconnection or continuous operation for 24 hours, the upstream and downstream water level data are filtered by sliding average, the head change of the day is analyzed, and the guide vane opening is sorted and the integrity of the guide vane power characteristic curve is calculated; A fifth-order polynomial curve fitting is performed on the power characteristic points of the guide vane power characteristic curve whose integrity is greater than 90% to form the guide vane power characteristic curve of the hydropower unit.

2. The online extraction method of the guide vane power characteristic curve of a hydropower unit according to claim 1 is characterized in that: The time series data include guide vane opening, unit active power, and water head height.

3. The online extraction method of the guide vane power characteristic curve of a hydropower unit according to claim 2 is characterized in that: Generate the starting power characteristic point of the guide vane power characteristic curve of the hydropower unit, specifically including: respectively obtain the mean of the guide vane opening, unit active power, and gross head data in the time series data of the period as the starting point of the guide vane power characteristic curve of the hydropower unit, denoted as (y ctg_x , P ctg_x , H ctg_x ), where y ctg_x P is the average guide vane opening of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change. ctg_x H is the average active power of the hydropower unit within 10 seconds when the guide vane opening does not change. ctg_x It is the average water head height of the hydropower unit within 10 consecutive seconds when the guide vane opening does not change.

4. The online extraction method of the guide vane power characteristic curve of a hydropower unit according to claim 3 is characterized in that: When the hydropower unit actually generates active power P act Enter the unit active power setting value P set When the active power target value of the hydropower unit is within the dead zone of ±0.01Pe, the adjustment is completed.

5. The method for online extraction of guide vane power characteristic curve of a hydropower unit according to claim 4, characterized in that: Form multiple other power characteristic points, specifically including: intercepting the time series data of the guide vane opening, active power of the unit, and upstream and downstream water head of the hydropower unit for 10 seconds after the adjustment is completed, and respectively calculating the mean of the guide vane opening, active power of the unit, and gross water head data in this time series data as other discrete points of the guide vane power characteristic curve of the hydropower unit, recorded as (y k_x , P k_x , H k_x ), where y k_x P is the average guide vane opening of the hydropower unit within 10 seconds after the unit is regulated. k_x H is the average active power of the hydropower unit within 10 seconds after the adjustment is completed. k_x It is the average water head height within 10 seconds after the hydropower unit is adjusted.

6. The method for online extraction of guide vane power characteristic curve of a hydropower unit according to claim 5, characterized in that: After the unit decoupling order is issued or the unit has been running continuously for 24 hours, the time series data of the upstream and downstream water levels of the power station are subjected to sliding average filtering to analyze the degree of head change on that day, and the guide vane power characteristic points within the head range obtained from the start-up of the unit to the current moment are sorted from small to large according to the guide vane opening.

7. The method for online extraction of guide vane power characteristic curve of a hydropower unit according to claim 6, characterized in that: The completeness of the guide vane power characteristic curve is calculated by the following formula: D=(y max -y min ) / 100 where y max is the maximum guide vane opening within the water head range, y max It is the minimum value of the guide vane opening within the head range.

8. The method for online extraction of guide vane power characteristic curve of a hydropower unit according to claim 7, characterized in that: If the completeness of the guide vane power characteristic curve in the head interval is greater than 90%, a fifth-order polynomial curve fitting is performed on all guide vane power characteristic points in the head interval, and the fitting curves formed by multiple head intervals constitute the guide vane-power characteristic curve.

Images