Calculation Methods for Expanding the Capacity of Cascade Hydropower Stations

Abstract

The present invention provides a method for calculating the expansion planning of cascade hydropower stations, which relates to the technical field of the expansion planning of hydropower stations. By judging whether each hydropower station in the cascade hydropower stations can be expanded, the expandable hydropower stations to be expanded are obtained and sorted according to the cascade. Taking the last expandable hydropower station planned for expansion as the iterative object, iteration is carried out. By using the regulating storage capacity, the average peak shaving hours in the dry season and the average annual peak shaving hours of the next-level hydropower station required by the iterative object, the number of expansion units of the iterative object is judged. In this way, all the expandable hydropower stations to be expanded are iterated to obtain the overall expansion capacity of the river, solving the problem that the existing calculation scheme for the expansion capacity of hydropower stations ignores the matching of cascade diverted flow and leads to water abandonment in the power station. The present invention is applicable to the expansion planning and design of cascade hydropower stations.

Description

Technical Field

[0001] This invention relates to the field of hydropower station expansion technology, and in particular to a method for planning and calculating the expansion of cascade hydropower stations. Background Technology

[0002] Existing research on hydropower station expansion mainly focuses on the potential assessment of individual power stations, lacking in-depth consideration of the interconnectedness of river cascades. For example, CN114400716A discloses a method for selecting the capacity of hydropower station units for expansion, which ignores the balance of upstream and downstream cascade flow. This can easily lead to a mismatch in the flow of upstream and downstream power stations after the expansion of cascade hydropower stations, thus causing water wastage problems. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a method for calculating the expansion plan of cascade hydropower stations, which solves the problem of water wastage caused by neglecting the matching of cascade reference flow in existing hydropower station expansion capacity calculation schemes.

[0004] The technical solution adopted by this invention to solve the above-mentioned technical problems is a method for calculating the expansion planning of cascade hydropower stations, comprising the following steps: S1. Determine whether each hydropower station in the cascade hydropower station can be expanded, obtain the hydropower stations that can be expanded, and sort them according to the cascade. S2. The last hydropower station planned for expansion is used as the iteration object; S3. Get the current number of expansion units for the iterating object; S4. The calculation of the iteration object requires the regulating reservoir capacity of the next-level hydropower station, the average peak-shaving hours during the dry season, and the annual utilization hours after the expansion of the generator. S5. If the iterative object requires the regulating reservoir capacity of the next-level hydropower station to be greater than the regulating reservoir capacity of the next-level hydropower station, or the average peak-shaving hours during the dry season are less than the set average peak-shaving hours during the dry season, or the annual utilization hours after expansion are less than the set annual utilization hours after expansion, then the current number of expansion units is reduced by one to obtain the new current number of expansion units. S3 to S5 are repeated until the iterative object requires the regulating reservoir capacity of the next-level hydropower station to be no greater than the regulating reservoir capacity of the next-level hydropower station, the average peak-shaving hours during the dry season to be no less than the set average peak-shaving hours during the dry season, and the annual utilization hours after expansion to be no less than the set annual utilization hours after expansion. The number of expansion units of the iterative object is obtained, and the expansion planning of the iterative object is completed. S6. Take the previous hydropower station that is planned for expansion of the last planned hydropower station as the new iteration object, and repeat S3 to S6 until all planned hydropower stations have completed their expansion plans.

[0005] Furthermore, the method also includes: S7, calculating the expansion capacity of each expandable hydropower station, expansion capacity = number of expansion units × single unit capacity, and summing them to obtain the total expansion capacity of the cascade hydropower stations, and outputting the number of cascade hydropower stations that can be expanded, the capacity of each cascade hydropower station, and the total capacity of the cascade hydropower stations.

[0006] Furthermore, the rules for determining whether each hydropower station in a cascade hydropower station can be expanded include: if the development method of the next level hydropower station is diversion type or low-head riverbed type, then the current hydropower station cannot be expanded.

[0007] Furthermore, the initial value of the current number of expansion units is the maximum number of expansion units.

[0008] Furthermore, the formula for calculating the regulating reservoir capacity required by the next-level hydropower station for the iterative object is as follows: Regulating reservoir capacity required by the next-level hydropower station for the iterative object = (Total reference flow of the iterative object - Total reference flow of the next-level hydropower station) × Set annual average daily peak-shaving hours × 0.36, Total reference flow = Existing reference flow + Current expansion reference flow, Current expansion reference flow = Current number of expansion units × Single unit reference flow.

[0009] Furthermore, the formula for calculating the average peak-shaving hours during the dry season is: Average peak-shaving hours during the dry season = 24 ÷ installed capacity after expansion, installed capacity after expansion = installed capacity after expansion ÷ average output during the dry season of the designed dry year.

[0010] Furthermore, the annual utilization hours after expansion = multi-year average annual power generation ÷ capacity after expansion, capacity after expansion = capacity before expansion + capacity after expansion, and capacity after expansion = number of expansion units × single unit capacity.

[0011] The beneficial effects of this invention are as follows: This invention provides a method for calculating the expansion plan of cascade hydropower stations. By determining whether each level of the cascade hydropower station can be expanded, the method identifies the hydropower stations that can be expanded and sorts them according to the cascade. Taking the last hydropower station to be expanded as the iteration object, the method iterates through the required regulating reservoir capacity of the next level hydropower station, the average peak-shaving hours during the dry season, and the annual average peak-shaving hours to determine the number of units that can be expanded. This process is repeated for all the hydropower stations that can be expanded to obtain the overall expansion capacity of the river. This solves the problem of existing hydropower station expansion capacity calculation schemes neglecting the matching of cascade reference flow, which leads to water wastage by the power station. In this invention, a reverse iterative logic is used to calculate the downstream reservoir capacity's ability to accept the upstream expansion flow and the average peak-shaving hours during the dry season. The calculation is repeatedly iterated and verified to scientifically determine the optimal expansion scale for each cascade. This effectively balances the overall benefits of the basin with the regulating potential of individual stations. While making full use of existing facilities and reducing water wastage during the flood season, it improves the effective capacity of the power grid through precise flow matching, providing stable regulation support for the new power system. Attached Figure Description

[0012] Figure 1 This is a flowchart illustrating a method for calculating the expansion of a cascade hydropower station, as provided by this invention. Detailed Implementation

[0013] This invention addresses the problem of power station water energy loss caused by neglecting cascade linkage in existing hydropower station expansion planning, and provides a calculation method for cascade hydropower station expansion planning, such as... Figure 1 As shown, it includes the following steps: S1. Determine whether each hydropower station in the cascade hydropower station can be expanded, obtain the hydropower stations that can be expanded, and sort them according to the cascade.

[0014] Specifically, the rules for determining whether each hydropower station in a cascade hydropower station can be expanded include: if the development method of the next hydropower station is diversion type or low-head riverbed type, then the current hydropower station cannot be expanded.

[0015] S2. The last hydropower station planned for expansion is used as the iteration object.

[0016] S3. Get the current number of expansion units of the iterating object.

[0017] Specifically, the initial value of the current number of expansion units is the maximum number of expansion units.

[0018] S4. The calculation of the iteration object requires the regulating reservoir capacity of the next-level hydropower station and the average peak-shaving hours during the dry season.

[0019] Specifically, the formula for calculating the regulating reservoir capacity required by the next-level hydropower station for the iterative object is as follows: Regulating reservoir capacity required by the next-level hydropower station for the iterative object = (Total reference flow of the iterative object - Total reference flow of the next-level hydropower station) × Set annual average daily peak-shaving hours × 0.36, Total reference flow = Existing reference flow + Current expansion reference flow, Current expansion reference flow = Current number of expansion units × Single unit reference flow.

[0020] The formula for calculating the average peak-shaving hours during the dry season is: Average peak-shaving hours during the dry season = 24 ÷ installed capacity after expansion, installed capacity after expansion = installed capacity after expansion ÷ average output during the dry season of the designed dry year.

[0021] S5. If the iterative object requires the regulating reservoir capacity of the next-level hydropower station to be greater than the regulating reservoir capacity of the next-level hydropower station, or the average peak-shaving hours during the dry season are less than the set average peak-shaving hours during the dry season, or the annual utilization hours after expansion are less than the set annual utilization hours after expansion, then the current number of expansion units is reduced by one to obtain the new current number of expansion units. S3 to S5 are repeated until the iterative object requires the regulating reservoir capacity of the next-level hydropower station to be no greater than the regulating reservoir capacity of the next-level hydropower station, the average peak-shaving hours during the dry season to be no less than the set average peak-shaving hours during the dry season, and the annual utilization hours after expansion to be no less than the set annual utilization hours after expansion. The number of expansion units of the iterative object is obtained, and the expansion planning of the iterative object is completed.

[0022] Specifically, for the same hydropower station facing expansion, the number of expansion units is verified by adjusting reservoir capacity, average peak-shaving hours during the dry season, and annual utilization hours after expansion. This ensures that each planned expandable hydropower station can meet the reservoir capacity and average peak-shaving hours requirements during the dry season after expansion, thus guaranteeing peak-shaving capacity while improving hydropower utilization. The set annual utilization hours after expansion can be 1825 hours.

[0023] S6. Take the previous hydropower station that is planned for expansion of the last planned hydropower station as the new iteration object, and repeat S3 to S6 until all planned hydropower stations have completed their expansion plans.

[0024] Example: Taking a 10-level hydropower station as an example, this invention will be further explained. The 2nd, 4th, 8th, and 9th level hydropower stations are planned for expansion. First, taking the 9th level hydropower station as the iterative object, with the maximum number of expansion units as the initial value, the regulating reservoir capacity and average peak-shaving hours during the dry season required by the 10th level non-expandable hydropower station for the 9th level hydropower station are calculated. Since the 10th level is a non-expandable hydropower station, its regulating reservoir capacity is a known constant. Therefore, the required regulating reservoir capacity of the 10th level hydropower station is determined by the 9th level hydropower station. The relationship between the regulating reservoir capacity of the non-expandable hydropower station and the regulating reservoir capacity of the 10th-level non-expandable hydropower station, and the relationship between the average peak-shaving hours of the 9th-level hydropower station during the dry season and the set average peak-shaving hours during the dry season, are used to determine whether the number of additional generating units for the 9th-level hydropower station meets the requirements. If not, the number of generating units is reduced by one, and the requirement is checked again until the number of additional generating units for the 9th-level hydropower station meets the requirements. This process uniquely determines the regulating reservoir capacity of the 9th-level hydropower station. Then, the 8th-level hydropower station is used as the iteration object to obtain the number of additional generating units for the 8th-level hydropower station that meets the requirements. The 4th-level hydropower station is used as the iteration object to obtain the number of additional generating units for the 4th-level hydropower station that meets the requirements. The 2nd-level hydropower station is used as the iteration object to obtain the number of additional generating units for the 2nd-level hydropower station that meets the requirements. This process completes the expansion planning for all expandable hydropower stations that are planned for expansion.

Claims

1. A method for calculating the expansion planning of a cascade hydropower station, characterized in that, The method comprises the following steps: S1, judging whether each cascade hydropower station in the cascade hydropower station can be expanded, obtaining the expandable hydropower stations to be expanded, and sorting according to the cascade; S2, taking the last expandable hydropower station to be expanded as an iteration object; S3, obtaining the current expansion number of the iteration object; S4, calculating the regulation storage capacity of the next cascade hydropower station required by the iteration object, the average peak shaving hours in the dry season, and the annual utilization hours after expansion; S5, if the regulation storage capacity of the next cascade hydropower station required by the iteration object is greater than the regulation storage capacity of the next cascade hydropower station, or the average peak shaving hours in the dry season is less than the set average peak shaving hours in the dry season, or the annual utilization hours after expansion is less than the set annual utilization hours after expansion, then the current expansion number is reduced by one as a new current expansion number, and S3 to S5 are repeated until the regulation storage capacity of the next cascade hydropower station required by the iteration object is not greater than the regulation storage capacity of the next cascade hydropower station, the average peak shaving hours in the dry season is not less than the set average peak shaving hours in the dry season, and the annual utilization hours after expansion is not less than the set annual utilization hours after expansion, the expansion number of the iteration object is obtained, and the expansion planning of the iteration object is completed; S6, taking the last expandable hydropower station to be expanded as a new iteration object, and repeating S3 to S6 until the expansion planning of all expandable hydropower stations to be expanded is completed.

2. The method according to claim 1, characterized in that, Further comprising: S7, calculating the expansion capacity of each expandable hydropower station, expansion capacity = expansion number × single machine capacity, summing up, obtaining the total expansion capacity of the cascade hydropower station, and outputting the cascade number of the expandable hydropower station, the capacity of each cascade hydropower station, and the total capacity of the cascade hydropower station.

3. The method according to claim 1, characterized in that, The rule for judging whether each cascade hydropower station in the cascade hydropower station can be expanded comprises: if the development mode of the next cascade hydropower station is diversion type or low water head river bed type, the current hydropower station cannot be expanded.

4. The method according to claim 1, characterized in that, The initial value of the current expansion number is the maximum expansion number.

5. The method of claim 1, wherein, The calculation formula of the regulation storage capacity of the next cascade hydropower station required by the iteration object is: regulation storage capacity of the next cascade hydropower station required by the iteration object = (total reference flow of the iteration object - total reference flow of the next cascade hydropower station) × set average daily peak shaving hours × 0.36, total reference flow = existing reference flow + current expansion reference flow, current expansion reference flow = current expansion number × single machine reference flow.

6. The method of claim 1, wherein, The calculation formula of the average peak shaving hours in the dry season is: average peak shaving hours in the dry season = 24 ÷ expansion after installed capacity ratio, expansion after installed capacity ratio = expansion after installed capacity ÷ design dry year dry season average output.

7. The method of claim 1, wherein, The annual utilization hours after expansion = multi-year average annual power generation ÷ expansion after capacity, expansion after capacity = expansion before capacity + expansion capacity, expansion capacity = expansion number × single machine capacity. The annual utilization hours after expansion = multi-year average annual power generation ÷ expansion after capacity, expansion after capacity = expansion before capacity + expansion capacity, expansion capacity = expansion number × single machine capacity.

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