A method for checking rationality of power plant generation plan adjustment

Abstract

The application provides a method for checking rationality of power generation plan adjustment of a hydropower station, comprising the following steps: S1, determining a safe and stable operation area of a unit according to a gross water head at a temporary adjustment plan time of a power grid, and taking into account an influence of subsequent water head changes; S2, unit output distribution and stable operation checking; and S3, reservoir safe operation checking. The method can check whether the adjusted power generation plan meets the safe and stable operation of the unit and the reservoir according to the current gross water head by introducing a margin coefficient of the influence of water head changes on the unit output, take into account the influence of subsequent water head changes, avoid the unit operation in a vibration area, reasonably distribute the output, fully utilize the power generation efficiency of the unit, and reduce the start-stop times of the unit.

Description

Technical Field

[0001] This invention relates to the field of hydropower station optimization scheduling technology, and in particular to a method for verifying the rationality of hydropower station power generation plan adjustments. Background Technology

[0002] Large hydropower stations typically have advantages such as large installed capacity and fast power output regulation, and play a major role in peak and valley regulation in the power grid's energy structure. Therefore, some hydropower stations adjust their power generation plans very frequently within a day in order to cooperate with the power grid's power regulation. However, the adjusted power generation plan often leads to the units operating in the vibration zone, affecting the safety and stability of the units. Furthermore, the changes in the water flow from the upstream reservoir cause the power generation head to change constantly, which may also lead to the units entering the vibration zone.

[0003] Large hydropower stations generally have multiple functions such as flood control, power generation, and ecological protection. While striving to maximize power generation benefits, flood control, ecological protection, and reservoir safety should also be taken into account. Therefore, hydropower stations are subject to strict constraints from many conditions during operation, such as outflow, hourly and daily water level fluctuations. Adjustments to the power generation plan may lead to the breach of various constraints on reservoir operation and affect reservoir safety.

[0004] Therefore, how to ensure the safe operation of the generating units and reservoirs while maximizing the power generation efficiency of the generating units when the power generation plan of a hydropower station is frequently adjusted is an urgent problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for verifying the rationality of the adjustment of the power generation plan of a hydropower station. By introducing a margin coefficient for the impact of head changes on the unit output, the stable operating zone of the unit is accurately determined, and the unit output is reasonably calculated and allocated to ensure the safety of the reservoir.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for verifying the rationality of adjustments to the power generation plan of a hydropower station, comprising the following steps:

[0007] S1. Determine the safe and stable operating zone of the unit based on the gross head at the time of the temporary adjustment plan of the power grid, and take into account the impact of subsequent head changes;

[0008] S2. Unit output distribution and stable operation verification;

[0009] S3. Verification of safe operation of reservoirs.

[0010] In a preferred embodiment, step S1 includes the following steps:

[0011] S1.1. Based on the generator model and adjustment time, and considering the generator set's gross head output curve, determine the safe and stable operating range of the computer unit, as shown in the following formula:

[0012]

[0013] In the formula, N min To adjust the minimum stable output of the unit corresponding to the planned gross head; N max To adjust the maximum stable output of the unit corresponding to the planned gross head; N d and N d * These represent the stable output of a single generating unit without considering head variation and with considering head variation, respectively; N e K is the rated output of a single unit; K is the margin factor, used to reflect the impact of head changes on the unit's output in subsequent periods.

[0014] S1.2 Each hydropower station sets a margin coefficient K based on its actual conditions and the actual inflow and outflow from the reservoir. When the inflow is large, the outflow is small, and the head shows a significant increasing trend, K takes a relatively large value; when the inflow is small, the outflow is large, and the head shows a significant decreasing trend, K takes a relatively small value. The safe and stable operating range of the unit after taking into account the head changes is as follows:

[0015]

[0016] In a preferred embodiment, step S2 includes the following steps:

[0017] S2.1 When the water head shows an increasing trend (K≥1), according to the original plan N... t The adjusted plan ΔN and the total adjustment time point T, and the minimum number of units required to start at each planned time point are calculated as follows:

[0018]

[0019] N t N t+1 ...N t+T The plan before adjustment is given for each time point from t to t+T; n t ,n t+1 ...n t+T The minimum number of machines started at each time point from t to t+T is the nearest integer value.

[0020] When the water head shows a decreasing trend (0 < K < 1), use K*N max Replace N max Then, equation (3) is used to calculate the minimum number of machines required to start at each planned time point;

[0021] S2.2 The output distribution of a single unit at each planned time point is calculated as follows:

[0022]

[0023] If N d N d+1 ...N d+T If all values ​​meet the requirements of the safe and stable operation zone in step S1.2, proceed to the next step; if any value does not meet the requirements, submit a modification request to the power grid dispatch center, and then repeat steps S2.1 and S2.2 until the requirements of the safe and stable operation zone in step S1.2 are met, and then proceed to the next step.

[0024] S2.3, Verify the minimum number of machines n to be started at each time point from t to t+T. t ,n t+1 ...n t+T The verification process for whether frequent start-stop events exist is as follows:

[0025]

[0026] If the inequality is true, it means that the unit is frequently starting and stopping at adjacent times. In this case, a modification request is submitted to the power grid dispatch, and then the process from S2.1 to S2.3 is repeated until the inequality is no longer true and the next process begins.

[0027] In the preferred embodiment, the reservoir safety operation verification in S3 includes hourly reservoir water level fluctuation verification, daily reservoir water level fluctuation verification, and ecological flow verification.

[0028] In the preferred embodiment, in step S3, the real-time inbound flow Q during the adjustment plan period is used as the basis. r Water consumption rate λ s Adjusted average hourly power output N sp Hourly average gate discharge flow Q sz and the hourly fluctuation limit Δh of water level sx The hourly water level fluctuation of the reservoir was checked, as follows:

[0029] First, using the reservoir's water level and capacity curve, we can find the flow rate Δq required for a 1cm change in reservoir water level per hour during planned adjustments. Then, we can determine the hourly water level fluctuation. If Δh s <Δh sx If the requirement is met, proceed to the daily water level fluctuation check of the reservoir; if Δh s >Δh sx If the power generation plan is not modified, the power grid dispatching department will request a modification. Then, the hourly water level fluctuation check in S2 and S3 will be repeated until the requirements are met, and then the daily water level fluctuation check will begin.

[0030] In the preferred embodiment, in step S3, the predicted inflow rate Q is... rp Daily average water consumption rate λ rp The adjusted daily power output N rp Average daily gate discharge flow Qrz and the daily water level fluctuation limit Δh rx The daily variation of reservoir water level is checked, as follows:

[0031] First, using the reservoir's water level and capacity curve, we can find the flow rate Δq required for a 1cm change in reservoir water level per hour during planned adjustments. Then, we can determine the daily water level fluctuation. If Δh r <Δh rx If Δh meets the requirements, proceed to ecological flow verification; r >Δh rx If the power generation plan is not modified, the power grid dispatching department will request modification of the power generation plan. Then, the hourly and daily water level fluctuation checks in S2 and S3 will be repeated until the requirements are met, at which point the ecological flow check will begin.

[0032] In the preferred embodiment, in step S3, based on the average daily water consumption rate λ rp The adjusted daily power output N rp Average daily gate discharge flow Q rz and ecological flow limit Q st The ecological flow verification is performed as follows:

[0033] If λ rp *N rp +Q rz >Q st If the plan is adjusted to meet the requirements, it can be executed; if λ rp *N rp +Q rz <Q st If the planned adjustment does not meet the requirements, an application must be made to the power grid dispatch center to modify the power generation plan. Then, the S2 and S3 processes are repeated until the requirements are met before execution.

[0034] The present invention provides a method for verifying the rationality of adjustments to a hydropower station's power generation plan, which has the following beneficial effects:

[0035] 1. This invention can fully consider changes in water head when the power grid temporarily adjusts the power generation plan, quickly and accurately calculate the safe and stable operating range of the hydropower station unit, and calculate and adjust the output according to the constraints of reservoir water level fluctuation and flow rate to ensure the safety of the reservoir.

[0036] 2. This invention, through reasonable calculation and distribution of power output, allows the hydropower unit to operate at the upper limit of the stable range as much as possible, fully utilizes the power generation efficiency of the generator unit, and avoids frequent start-ups and shutdowns of the unit.

[0037] 3. This invention can be widely used in hydropower stations where power generation plans are frequently adjusted, ensuring the safe operation of hydropower station units and reservoirs while optimizing unit operating conditions. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] Figure 1 This is an overall flowchart of the present invention;

[0040] Figure 2 Flowchart for generator set output allocation;

[0041] Figure 3 Flowchart for verifying constraints and limitations in reservoir operation;

[0042] Figure 4 This is a graph showing the gross head output of unit A at power station A.

[0043] Figure 5 A daily planned output curve for Power Plant A; Detailed Implementation

[0044] Combination Figures 1-3 The specific embodiments of the present invention will be described in further detail below.

[0045] A method for verifying the rationality of adjustments to a hydropower station's power generation plan includes the following steps:

[0046] S1. Based on the gross head at the time of the temporary power grid adjustment plan, determine the safe and stable operating zone of the generating unit, taking into account the impact of subsequent head changes. This specifically includes the following steps:

[0047] S1.1. Based on the generator model and adjustment time, and considering the generator set's gross head output curve, determine the safe and stable operating range of the computer unit, as shown in the following formula:

[0048]

[0049] In the formula, N min To adjust the minimum stable output of the unit corresponding to the planned gross head; N max To adjust the maximum stable output of the unit corresponding to the planned gross head; N d and N d * These represent the stable output of a single generating unit without considering head variation and with considering head variation, respectively; N e K represents the rated output of a single unit; K is the margin factor, used to reflect the impact of head changes on the unit's output in subsequent periods.

[0050] S1.2 Each hydropower station sets a margin coefficient K based on its actual conditions and the actual inflow and outflow from the reservoir. When the inflow is large, the outflow is small, and the head shows a significant increasing trend, K takes a relatively large value; when the inflow is small, the outflow is large, and the head shows a significant decreasing trend, K takes a relatively small value. The safe and stable operating range of the unit after taking into account the head changes is as follows:

[0051]

[0052] S2. Unit output distribution and stable operation verification, including the following steps:

[0053] S2.1 When the water head shows an increasing trend (K≥1), according to the original plan N... t The adjusted plan ΔN and the total adjustment time point T, and the minimum number of units required to start at each planned time point are calculated as follows:

[0054]

[0055] In the formula, N t N t+1 ...N t+T The plan before adjustment is given for each time point from t to t+T; n t ,n t+1 ...n t+T The minimum number of machines started at each time point from t to t+T is the nearest integer value.

[0056] When the water head shows a decreasing trend (0 < K < 1), use K*N max Replace N max Then, equation (3) is used to calculate the minimum number of machines required to start at each planned time point.

[0057] S2.2 The output distribution of a single unit at each planned time point is calculated as follows:

[0058]

[0059] If N d N d+1 ...N d+T If all values ​​meet the requirements of the safe and stable operation zone in step S1.2, proceed to the next process; if any value does not meet the requirements, submit a modification request to the power grid dispatch center, and then repeat steps S2.1 and S2.2 until the requirements of the safe and stable operation zone in step S1.2 are met, and then proceed to the next process.

[0060] S2.3, Verify the minimum number of machines n to be started at each time point from t to t+T. t ,n t+1 ...n t+T The verification process for whether frequent start-stop events exist is as follows:

[0061]

[0062] If the inequality holds true, it indicates frequent start-ups and shutdowns of generating units at adjacent time points. A modification request is then submitted to the grid dispatch center, and processes S2.1 through S2.3 are repeated until the inequality no longer holds true, proceeding to the next process. The minimum number of generating units in operation at each adjacent time point is checked using process S2.3.

[0063] Preferably, the hydropower station is divided into two single stations, left and right bank. Based on the load demand of the power grid, the adjusted stations can be categorized as follows: adjustment of either the left or right bank station; adjustment of both left and right bank stations; or mutual transfer between left and right bank stations. When adjusting either the left or right bank station, the S2.1–S2.3 process is performed according to the head change trend. When both left and right bank stations can be adjusted, the S2.1–S2.3 process is performed on both left and right bank stations respectively, based on the head change trend. The station on the left and right bank is selected as the planned adjustment station by comparing the safe and stable operation zone of the units and the number of unit start-ups and shutdowns, with fewer modification requests to the power grid dispatch center. When the left and right bank stations are transferred to each other, the adjustment plan ΔN of the transferring station is negative, and the adjustment plan ΔN of the transferred station is positive. The S2.1–S2.3 process is performed on both left and right bank stations respectively, based on the head change trend.

[0064] S3. Verification of reservoir safety operation. Verification of reservoir safety operation includes verification of hourly water level fluctuations, daily water level fluctuations, and ecological flow.

[0065] S3.1, Based on the real-time inbound flow Q during the adjustment period. r Water consumption rate λ s Adjusted average hourly power output N sp Hourly average gate discharge flow Q sz and the hourly fluctuation limit Δh of water level sx The hourly water level fluctuation of the reservoir was checked, as follows:

[0066] First, using the reservoir's water level and capacity curve, we can find the flow rate Δq required for a 1cm change in reservoir water level per hour during planned adjustments. Then, we can determine the hourly water level fluctuation. If Δh s <Δh sx If the requirement is met, proceed to the daily water level fluctuation check of the reservoir; if Δh s >Δh sx If the power generation plan is not modified, an application will be made to the power grid dispatch center. Then, S2 and S3.1 will be repeated until the requirements are met, and then the daily fluctuation of the reservoir water level will be checked.

[0067] S3.2, Based on the predicted inflow rate Q rp Daily average water consumption rate λrp The adjusted daily power output N rp Average daily gate discharge flow Q rz and the daily water level fluctuation limit Δh rx The daily variation of reservoir water level is checked, as follows:

[0068] First, using the reservoir's water level and capacity curve, we can find the flow rate Δq required for a 1cm change in reservoir water level per hour during planned adjustments. Then, we can determine the daily water level fluctuation. If Δh r <Δh rx If Δh meets the requirements, proceed to ecological flow verification; r >Δh rx If the power generation plan is not modified, a request is made to the power grid dispatch center. Then, steps S2, S3.1, and S3.2 are repeated until the requirements are met, at which point the process proceeds to ecological flow verification.

[0069] S3.3, Based on the average daily water consumption rate λ rp The adjusted daily power output N rp Average daily gate discharge flow Q rz and ecological flow limit Q st The ecological flow verification is performed as follows:

[0070] If λ rp *N rp +Q rz >Q st If the plan is adjusted to meet the requirements, it can be executed; if λ rp *N rp +Q rz <Q st If the planned adjustment does not meet the requirements, an application must be made to the power grid dispatch center to modify the power generation plan. Then, the S2 and S3 processes are repeated until the requirements are met before execution.

[0071] Taking Power Station A as an example, the current inflow to the reservoir is large, the outflow is small, and the spillway gates are all closed. The daily water level fluctuation limit Δh of the reservoir is [not specified]. rx The ecological flow limit is 2m, Q st 1160m 3 / s, with no hourly water level fluctuation limit requirement, the current power grid has temporarily increased the planned power generation ΔN of the left bank single plant of Power Station A from 1:00 to 7:00 by 300,000 kW, and the current gross head H a The predicted inflow rate is 126.1 m. rp 5900m 3 / s, average daily water consumption rate λ rp It is 8.86m 3 / s / 10,000 kW, average daily power output of the power station before adjustment (N) rp * is 4.32 million kW, Nrp The flow rate Δq required for a 1 cm change in reservoir water level per hour is 241 m³. 3 / s.

[0072] According to the hair water head H a 126.1m, combined Figure 4 The generator set's gross head output curve, calculated from the data, indicates that the safe and stable operating range of the unit is 53.74 ≤ N. d ≤84.49 (ten thousand kW).

[0073] Considering the large inflow and small outflow from the reservoir, resulting in an increasing head, and to ensure stable unit operation, a margin coefficient K = 1.05 is set based on a comprehensive assessment of water level changes. The safe and stable operating range of the unit after considering head changes is: K*N min (=56.43)≤N d ≤K*N max (=88.71)≤N e (=85).

[0074] Furthermore, the stable operating range of the unit is obtained: 56.43≤N d ≤84.49 (ten thousand kW).

[0075] Based on the determined stable operating area and Figure 5 Calculate the minimum number of generating units to be started at each time point (1:00 to 7:00) during the power generation plan adjustment:

[0076]

[0077] The minimum number of units that can be started calculated by the above formula is rounded up to the nearest integer value:

[0078]

[0079] Furthermore, calculate the output allocation of a single unit at each planned adjustment point:

[0080]

[0081] Verify whether the output of each unit falls within the stable operating range at each time point: N d(4:00～6:45) =45<56.43, N d(7:00) =55 < 56.43, which does not meet the requirements. Therefore, an application should be made to the power grid dispatching department for a minimum increase of 530,000 kW in the power generation plan from 4:00 to 6:45 and a minimum increase of 330,000 kW in the power generation plan from 7:00 to meet the requirements for stable operation of the unit.

[0082] Furthermore, verify whether there are frequent start-stop times for the minimum number of machines started at each time point: n 1:00～3:15 =n 3:30～3:45 =n 4:00～6:15 =n7:00 =2, there is no frequent start-up and shutdown of the unit, which meets the requirements.

[0083] Furthermore, the daily variation of the reservoir water level is checked, as follows:

[0084]

[0085] Daily fluctuation of reservoir water level

[0086] Δh r =1.97<Δh rx =2, then the requirement is met.

[0087] Furthermore, the ecological flow of the reservoir was verified, as follows:

[0088] If λ rp *N rp =442.39 * 8.86 = 3919 > Q st =1160 (m3 / s), then the plan adjustment meets the requirements and can be executed.

Claims

1. A method for verifying the rationality of adjustments to a hydropower station's power generation plan, characterized in that, Includes the following steps: S1. Determine the safe and stable operating zone of the unit based on the gross head at the time of the temporary adjustment plan of the power grid, and take into account the impact of subsequent head changes; S2. Unit output distribution and stable operation verification, including the following steps: S2.1 When the water head shows an increasing trend, that is... hour, This is the margin factor, based on the plan before adjustment. Adjustment plan and the total time point of adjustment The minimum number of units required to be started at each planned time point is calculated as follows: （3）； in, for Plans before adjustments at each point in time; for The minimum number of units started at each time point is rounded up to the nearest integer value. To adjust the maximum stable output of the unit corresponding to the planned gross head; When the water head shows a decreasing trend, that is When, use replace Then, equation (3) is used to calculate the minimum number of machines required to start at each planned time point; S2.2 The output distribution of a single unit at each planned time point is calculated as follows: （4）； like If all values ​​meet the requirements of the safe and stable operation zone in step S1, proceed to the next step; if any value does not meet the requirements, submit a modification request to the power grid dispatch center, and then repeat steps S2.1 and S2.2 until the requirements of the safe and stable operation zone are met, and then proceed to the next step. S2.3, Verification Minimum number of units started at each time point The verification process for whether frequent start-stop events exist is as follows: （5）； If the inequality is true, it means that the unit is frequently starting and stopping at adjacent times. In this case, a modification request is submitted to the power grid dispatch, and then the process of S2.1 to S2.3 is repeated until the inequality is no longer true and the next process is entered. S3. Verification of safe operation of reservoirs, including verification of hourly water level fluctuations, daily water level fluctuations, and ecological flow. Based on real-time inbound flow during the adjustment period Water consumption rate Adjusted average hourly output of the power station Hourly average gate discharge and hourly water level fluctuation limits The hourly water level fluctuation of the reservoir was checked, as follows: First, using the reservoir's water level and capacity curve, we can find the flow rate required for a 1cm change in the reservoir's water level per hour during the planned adjustment. The hourly fluctuation of the reservoir water level ,like If the requirement is met, proceed to the daily water level fluctuation check of the reservoir; if If the power generation plan is not modified, the power grid dispatching department will request a modification. Then, the hourly water level fluctuation check in S2 and S3 will be repeated until the requirements are met, and then the daily water level fluctuation check will begin.

2. The method for verifying the rationality of hydropower station power generation plan adjustments according to claim 1, characterized in that, S1 includes the following steps: S1.

1. Based on the generator model and adjustment time, and considering the generator set's gross head output curve, determine the safe and stable operating range of the computer unit, as shown in the following formula: （1）； In the formula, To adjust the minimum stable output of the unit corresponding to the gross head at the planned time; To adjust the maximum stable output of the unit corresponding to the planned gross head; and The stable output of a single unit is calculated by considering both head variation and head variation. Rated output of a single unit; This is a margin factor used to reflect the impact of head changes on unit output in subsequent periods; S1.2 Each hydropower station shall set a margin coefficient based on the actual conditions within the station and the actual inflow and outflow of water from the reservoir. When the inflow is large, the outflow is small, and the water head shows a significant increasing trend, Take the relatively larger value; when the inflow is smaller, the outflow is larger, and the head shows a significant decreasing trend. Taking a relatively smaller value, the safe and stable operating range of the unit after considering head changes is shown below: （2）。 3. The method for verifying the rationality of hydropower station power generation plan adjustments according to claim 1, characterized in that, In step S3, based on the predicted inflow rate... Daily average water consumption rate The adjusted daily power output of the power station Average daily gate discharge and daily water level fluctuation limits The daily variation of reservoir water level is checked, as follows: First, using the reservoir's water level and capacity curve, we can find the flow rate required for a 1cm change in the reservoir's water level per hour during the planned adjustment. The daily fluctuation of the reservoir water level ,like If the requirement is met, proceed to ecological flow verification; if If the power generation plan is not modified, the power grid dispatching department will request modification of the power generation plan. Then, the hourly and daily water level fluctuation checks in S2 and S3 will be repeated until the requirements are met, at which point the ecological flow check will begin.

4. The method for verifying the rationality of hydropower station power generation plan adjustments according to claim 1, characterized in that, In S3, based on the average daily water consumption rate The adjusted daily power output of the power station Average daily gate discharge and ecological flow limits The ecological flow verification is performed as follows: like If the plan is adjusted to meet the requirements, it can be executed; if If the planned adjustment does not meet the requirements, an application must be made to the power grid dispatch center to modify the power generation plan. Then, the S2 and S3 processes are repeated until the requirements are met before execution.

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