A power balance calculation method for cascade hydropower stations in a power system

Abstract

The application provides a cascade hydropower station group power balance calculation method in a power system, and relates to the technical field of power system planning. The application comprises three steps of obtaining characteristic values of cascade power station output and overall output process after balance, calculating preliminary output distribution based on power proportion, and calculating output redistribution after rationality judgment. The application can solve the problem of cascade hydropower station output distribution after power system balance, and considers the hydraulic connection between cascade hydropower stations during distribution, so that the distributed output is more reasonable and accurate, and each cascade hydropower station can fully exert its capacity and power benefit, which is a scientific, reasonable and effective calculation method.

Description

Technical Field

[0001] This invention belongs to the field of power system planning, and specifically relates to a method for calculating the power balance of a cascade hydropower station group in a power system. Background Technology

[0002] Power balance is a crucial aspect of power system planning and design, as well as power source planning and design. It forms the foundation for justifying the necessity and scale of power plant construction and is a key guideline for power plant generation. When cascade hydropower stations participate in the power system balance, the output after runoff regulation is typically included in the overall balance calculation. While the overall power system balance yields the output of the cascade hydropower stations, the balance output of each individual station is not calculated. The balance output of each cascade station within the power system forms the basis for benefit analysis and scale justification, and is also a vital reference for guiding each station to generate power to meet the needs of the power system. Therefore, calculating the power balance of a group of cascade hydropower stations within a power system is of great significance.

[0003] However, current power balance studies rarely delve into the output allocation of cascade hydropower stations in power systems, and mainly focus on the overall participation of the cascade in the balance. Summary of the Invention

[0004] Based on the background technology, this invention proposes a method for calculating the power balance of a cascade hydropower station group in a power system. This method not only solves the problem of power output allocation of cascade hydropower stations after the power system is balanced, but also considers the hydraulic connection between cascade hydropower stations during the allocation, making the allocated power output more reasonable and accurate. This allows each cascade hydropower station to fully utilize its capacity and power efficiency, making it a scientific, reasonable and effective calculation method.

[0005] The technical solution of the present invention: A method for calculating the power balance of a cascade hydropower station group in a power system includes three steps: obtaining the output characteristic values ​​of the cascade power stations and the overall output process after balance; calculating the initial output allocation based on the power ratio; and calculating the output redistribution after rationality judgment.

[0006] The first step involves obtaining the characteristic values ​​of the output of cascade hydropower stations and the overall output process after balancing. Based on the calculation results of joint runoff regulation of cascade hydropower stations, the average output of each cascade hydropower station within a unified balancing period (represented by a month) is obtained. The expected output of each cascade hydropower station is determined according to the system maintenance schedule, standby schedule, and the obstruction situation of each cascade hydropower station within the month. Forced output of the cascade hydropower stations is further deducted, where forced output refers to the greater of the minimum stable operating output of a single unit and the ecological base load. After deduction, the monthly average output and expected output of each cascade hydropower station are obtained for allocation calculations, where average output represents electricity and expected output represents capacity. The average output and expected output of each cascade hydropower station are summed to obtain the overall average output and expected output of the cascade, as shown below: (Formula 1) (Formula 2) In the formula: , The figures are the projected and average output of the entire cascade hydropower project in a given month, in MW; This refers to the serial numbers of the cascade hydropower stations. The number of cascade hydropower stations; , The first The projected and average output (MW) of a cascade hydropower station in a certain month; the projected and average outputs here are output characteristic values ​​after deducting forced output.

[0007] After balancing the cascade hydropower stations as a whole in the power system, the generation position of the entire cascade in terms of monthly power load and the hourly power output within the month are obtained. The sum of the forced output of each cascade hydropower station is then deducted to obtain the hourly power output of the entire cascade for allocation. ,in This represents the time of the month. If the month has 30 days, then the total time is 720 hours.

[0008] The second step is the preliminary power output allocation calculation based on the electricity ratio. The hourly power output of the entire cascade hydropower station within the month, obtained after balancing, is initially allocated according to the average monthly power output weight of each cascade hydropower station, as follows: (Formula 3) In the formula: The first in the cascade hydropower project After the initial allocation of the hydropower stations, the first MW (Power Utility) is constantly being exerted.

[0009] If the output of each cascade hydropower station after allocation is less than or equal to the expected output for the month, that is... If the power output allocation is reasonable, then by further superimposing the forced power output of each cascade hydropower station in that month, we can obtain the hourly power output process of each cascade hydropower station in the power system for that month, as follows: (Formula 4) In the formula: The first in the cascade hydropower project The first hydropower station after the power system balance distribution The output at all times, MW; For the first The forced output of the hydropower station in that month was MW; The meaning of the result.

[0010] The third step is the recalculation of output allocation after the rationality assessment. If the output allocation after the initial allocation in the second step results in an output distribution at any power station at any time... The output is greater than the power plant's expected output. If the initial allocation result in the second step is unreasonable, the output needs to be recalculated. The specific approach is as follows: ① Calculate the monthly average power output rate of each cascade hydropower station. The calculation uses the average output rate after deducting forced output and the expected output rate. The cascade hydropower stations are then reordered from smallest to largest. The specific calculation is as follows: (Formula 5) In the formula: To arrange by power output from smallest to largest Average power output of No. 1 power station.

[0011] ② First, the power station ranked 1 is allocated. The projected and average output of power station 1 are divided into two parts. One part of the projected and average output is used to find a position within the overall cascade power output for power balance, ensuring that the average output rate of the remaining average and projected output of power station 1 is equal to the average output rate of power station 2. This calculation was obtained through trial and error. The trial calculation approach is as follows: For power station 1, the projected output is gradually increased from zero. A position is found at the top of the overall cascade output. The projected output is then used to cut across the top of the overall output, and electricity is used to fill the upper output area. This yields the partial output process of power station 1 within the overall cascade output. When exerting effort in a certain anticipated manner If the average output rate calculated from the remaining average output and the expected output of Power Station No. 1 is equal to that of Power Station No. 2, then the average output and expected output of both parts are calculated. The remaining average output and expected output of Power Station No. 1 are then superimposed with those of Power Station No. 2 to form a new Power Station No. 2'. The expected output of Power Station No. 1 and the expected output of Power Station No. 2' included in Power Station No. 2' are calculated as follows: (Formula 6) (Formula 7) (Formula 8) In the formula: The planned power output (MW) for Power Station 1, which is included in the new Power Station 2'; The projected output (MW) of Power Station No. 1 is used to locate its position in the overall power output of the cascade system. To contribute MW to the planned power output of the new power station No. 2'.

[0012] ③ For the new No. 2' power station, its allocation method is the same as that of No. 1 power station described in Part ②. The expected output and average output are divided into two parts. The power balance is carried out by using part of the expected output and average output in the remaining overall output of the cascade, so as to obtain the expected output of the No. 2' power station to find its position in the overall output of the cascade. and part of the power output process The remaining total output of the cascade needs to be reduced by the output already allocated to Power Station No. 1, so that the remaining average output of the new Power Station No. 2' is equal to the expected output. The calculated average power output is equal to that of Power Station No. 3. The trial calculation approach is the same as described in Part ② above. Then, the remaining average and projected power output of the new Power Station No. 2' are superimposed with that of Power Station No. 3 to form the new Power Station No. 3'. For the new Power Station No. 2', the projected power output that achieves positional balance within the overall cascade power output is determined. The projected output of both Power Station 1 and Power Station 2 can be calculated based on their respective proportions of the projected output of the new Power Station 2', as follows: (Formula 9) In the formula, For sorting ( The No. 2 power station is used in the new No. 2' power station to find the expected output in the overall output of the cascade, which is MW.

[0013] The calculated remaining power output of power plants 1 and 2, which will be used to form a new power plant 3' with power plant 3, is as follows: (Formula 10) In the formula, For sorting ( The projected output of Power Station No. 3' in the new Power Station No. 3' is MW.

[0014] The expected output of Power Station No. 3 is obtained by superimposing the expected output of Power Station No. 3'. The specific formula is as follows: (Formula 11) (Formula 12) By further repeating the trial calculation approach described in Part ②, we can obtain the expected output of the new power station No. 3' in finding its position for balance within the overall cascade output. and part of the power output process ④ By repeating the above steps one by one, the expected output of the new power station (n-1)' and the expected output of power stations 1 to (n-1) in the new power station (n-1)' can be obtained. At the same time, the partial output process of the new power station (n-1)' in finding its position and achieving equilibrium in the overall output of the cascade can be obtained. The average output and expected output of the remaining part of power station (n-1)' are superimposed with power station n to form a new power station n'. The remaining total power generation output is... The allocation is carried out in power plants numbered 1 through n.

[0015] ⑤ Further, based on the partial power output processes of power stations 1 and 2' to (n-1)' in the overall cascade power output, and the projected power outputs of power stations 1 to (n-1) in 2' to (n-1)', combined with the remaining projected power outputs of power stations 1 to (n-1) in the new power station n' and the remaining overall cascade power output, and considering the forced output of each cascade hydropower station, the hourly power output process of each cascade hydropower station within the month, after the power system's power balance, considering the cascade hydraulic connection, can be calculated. The specific formula is as follows: (Formula 13) (Formula 14) In the formula: To rank Power Station No. 1 after the power system balance distribution The output at all times, MW; After finding a position for balance in the overall output of the cascade power station No. 1, the [number]th [unit / stage] The output at all times, MW; for After finding its position and balancing its overall output across the cascade power station, the [number] power station... The output at all times, MW; For Power Station No. 1 The projected output of Power Station No. 1, in MW; for The projected output of Power Station No. 1 is MW; for No. 1 power station The projected output of Power Station No. 1, in MW; The remaining cascade stages as a whole when reaching the last power station in the sequence. MW (Power Utility) is constantly being exerted.

[0016] This allows us to obtain the hourly output of each hydropower station in the cascade hydropower station group within a month after the power system is balanced. Calculating the output for each month yields the hourly output for the year.

[0017] Beneficial effects The proposed method for calculating the power balance of a cascade hydropower station group in a power system fills the gap in the method for calculating the hourly output of a single cascade hydropower station in power balance calculations. It is clear in its approach, innovative in its methodology, and reasonable in its implementation. The calculation method involves calculating the average output of each hydropower station within a unified balancing period (generally monthly, ten-day, or weekly, with monthly being the representative in this scheme) based on the joint runoff regulation method of the cascade hydropower stations with hydraulic connections. This determines the expected output within each balancing period. The cascade hydropower stations first participate in the power system balancing as a whole, yielding the overall power generation output process after the cascade is balanced. Then, based on the ratio of the expected output to the average output within each cascade power station's balancing period, the overall output process is rationally allocated to each cascade power station, taking into account power generation and capacity utilization. This invention considers the hydraulic connections and coordinated operation between cascade hydropower stations, while fully taking into account the simultaneous utilization of the capacity and power generation benefits of each cascade hydropower station. It can calculate the hourly output process of each cascade hydropower station after the power system achieves power balance, providing an important foundation for the benefit analysis and scale demonstration of cascade hydropower stations. It also serves as an important reference for guiding each cascade hydropower station to generate electricity in accordance with the power system's needs. This invention is mainly used to allocate the output of each cascade hydropower station based on the overall output of the cascade hydropower station group after the power system has achieved power balance. This method considers the hydraulic connections between cascade hydropower stations, enabling coordinated operation. Under the premise of regulation by the leading cascade reservoirs, it optimizes the power generation scheduling mode of each cascade, reduces the downstream cascade regulation reservoir capacity demand and water level fluctuations, and avoids additional water wastage in the downstream cascade. Attached Figure Description

[0018] Appendix Figure 1 Overall conceptual diagram of the invention; Appendix Figure 2 The flowchart and approach for calculating the third step Appendix Figure 3 A chart showing the characteristic values ​​and ranking of the output of a cascade hydropower station in a certain month; Appendix Figure 4 This is a schematic diagram showing the hourly output results of a cascade hydropower station after a certain month's balance. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example. A method for calculating the power balance of a cascade hydropower station group in a power system, such as... Figure 1 As shown, the process includes: first, obtaining the characteristic values ​​of the output of the cascade power stations and the overall output process after balancing; second, calculating the initial output allocation based on the power ratio; and third, calculating the output redistribution after a rationality judgment.

[0021] The first step specifically involves obtaining the characteristic values ​​of the output of the cascade hydropower stations and the overall output process after balancing. Based on the calculation results of joint runoff regulation of the cascade hydropower stations, the average output of each cascade hydropower station within a unified balancing period (represented by a month) is obtained. The expected output of each cascade hydropower station is determined according to the system maintenance schedule, standby schedule, and the obstruction situation of each cascade hydropower station within the month. The forced output of the cascade hydropower stations is further deducted to obtain the following: Figure 3 The figures for each cascade hydropower station are used for allocation calculations, showing the average monthly output and projected output of each station. Average output represents electricity generation, and projected output represents capacity. The average output of the entire cascade is obtained by summing the average and projected outputs of each station. and expected effort .

[0022] After balancing the cascade hydropower stations as a whole in the power system, the generation position of the entire cascade in terms of monthly power load and the hourly power output within the month are obtained. The sum of the forced output of each cascade hydropower station is then deducted to obtain the hourly power output of the entire cascade for allocation. ,in This represents the time of the month. If the month has 30 days, then the total time is 720 hours.

[0023] The second step involves calculating the hourly output of each cascade power station within the month based on the preliminary allocation of power generation ratio and average output ratio. The specific formula is as follows: ; In the formula: The first in the cascade hydropower project After the initial allocation of the hydropower stations, the first MW (Power Utility) is constantly being exerted.

[0024] If the output of each cascade hydropower station is allocated All are less than or equal to the expected output for the month. If the power output allocation is reasonable, then by further superimposing the forced power output of each cascade hydropower station in that month, we can obtain the hourly power output process of each cascade hydropower station in the power system for that month, specifically: ; In the formula: The first in the cascade hydropower project The first hydropower station after the power system balance distribution The output at all times, MW; For the first The forced output of the hydropower station in that month was MW; The meaning of the result.

[0025] The third step specifically involves the recalculation of output redistribution after the rationality assessment. The specific calculation approach and steps are as follows: Figure 2 As shown.

[0026] The power redistribution calculation following the aforementioned rationality assessment first calculates the monthly average power output rate of each cascade power station. ,Right now And reorder the cascade power stations from smallest to largest, such as Figure 3 As shown.

[0027] The power output redistribution calculation following the aforementioned rationality assessment first allocates power to the No. 1 power station. The expected and average power output of No. 1 power station are divided into two parts. Specifically, for No. 1 power station, the expected output is gradually increased from zero. At the top of the overall cascade output, the expected output is used to cut across the top of the overall output, and the uppermost output area is filled using electricity. This yields the partial power output process of No. 1 power station within the overall cascade output. When exerting effort in a certain anticipated manner If the average output rate calculated from the remaining average output and the expected output of Power Station No. 1 is equal to that of Power Station No. 2, then the average output and expected output of both parts are calculated. The remaining average output and expected output of Power Station No. 1 are then superimposed with those of Power Station No. 2 to form a new Power Station No. 2'. The expected output of Power Station No. 1 and the expected output of Power Station No. 2' included in Power Station No. 2' are calculated as follows:

[0028]

[0029]

[0030] In the formula: The planned power output (MW) for Power Station 1, which is included in the new Power Station 2'; The projected output (MW) of Power Station No. 1 is used to locate its position in the overall power output of the cascade system. To contribute MW to the planned power output of the new power station No. 2'.

[0031] Furthermore, for the new No. 2' power station, its allocation method is the same as that of the aforementioned No. 1 power station, to obtain the expected output of the No. 2' power station in finding its position to balance the overall output of the remaining cascade. and part of the power output process The remaining total output of the cascade needs to be reduced by the output already allocated to Power Station No. 1, and the remaining average output of the new Power Station No. 2' is compared with the expected output. The calculated average power output rate is equal to that of Power Station No. 3. Therefore, the remaining average and projected output of New Power Station No. 2' are superimposed with those of Power Station No. 3 to form a new New Power Station No. 3'. For New Power Station No. 2', the projected output that achieves positional balance within the overall cascade output is determined. The projected output of both Power Station 1 and Power Station 2 can be calculated based on their respective proportions of the projected output of the new Power Station 2', as follows:

[0032] In the formula, For sorting ( The No. 2 power station is used in the new No. 2' power station to find the expected output in the overall output of the cascade, which is MW.

[0033] Furthermore, the projected output of the remaining power from power plants 1 and 2, to be used in conjunction with power plant 3 to form a new power plant 3', is calculated as follows: ; In the formula, For sorting ( The projected output of Power Station No. 3' in the new Power Station No. 3' is MW.

[0034] The expected output of Power Station No. 3 Superimposing these values ​​yields the projected output of the new power station No. 3'. .

[0035] By repeating the aforementioned allocation approach, we can obtain the expected output of the new power station No. 3' in finding its position to achieve overall power output balance within the cascade system. and part of the power output process By repeating the aforementioned steps and calculating one by one, the expected output of the new power station (n-1)' and the expected output of power stations 1 to (n-1) in the new power station (n-1)' can be obtained. At the same time, the partial output process of the new power station (n-1)' in finding its position and achieving equilibrium in the overall output of the cascade can also be obtained. The remaining output of power station (n-1)' is superimposed with that of power station n to form a new power station n', and the total remaining power output of the cascade is [data missing]. The allocation is carried out in power plants numbered 1 through n.

[0036] Based on the partial power output processes of power stations 1 and 2' to (n-1)' in the overall cascade power output, and the projected power outputs of power stations 1 to (n-1) in power stations 2' to (n-1)', combined with the remaining projected power outputs of power stations 1 to (n-1) in the new power station n' and the remaining overall cascade power output, and considering the forced output of each cascade hydropower station, the hourly power output process of each cascade hydropower station within the month, after the power system's power balance, considering the cascade hydraulic connection, can be calculated. The specific formula is as follows:

[0037]

[0038] In the formula: To rank Power Station No. 1 after the power system balance distribution The output at all times, MW; After finding a position for balance in the overall output of the cascade power station No. 1, the [number]th [unit / stage] The output at all times, MW; for After finding its position and balancing its overall output across the cascade power station, the [number] power station... The output at all times, MW; For Power Station No. 1 The projected output of Power Station No. 1, in MW; for The projected output of Power Station No. 1 is MW; for No. 1 power station The projected output of Power Station No. 1, in MW; The remaining cascade stages as a whole when reaching the last power station in the sequence. MW (Power Utility) is constantly being exerted.

[0039] like Figure 4 As shown, when n is 6 and the corresponding output characteristic value in the figure is obtained, the hourly output process of each cascade hydropower station within the month after the power system power balance is obtained by following the above steps.

[0040] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for calculating the power balance of a cascade hydropower station group in a power system, characterized in that: The first step is to obtain the characteristic values ​​of the output of the cascade power stations and the overall output process after balancing; The second step is to perform preliminary output allocation calculations based on the proportion of electricity consumption. The third step is to recalculate the output allocation after the rationality assessment. The first step is to obtain the average output of each cascade hydropower station within a unified balancing period represented by a month, based on the joint runoff regulation calculation results of the cascade hydropower stations. Then, the expected output of each cascade hydropower station is determined according to the system maintenance schedule, standby schedule, and the obstruction situation of each cascade hydropower station within the month. Finally, the forced output of the cascade hydropower stations is deducted. Forced output refers to the greater of the minimum stable operating output of a single unit and the ecological base load. After deduction, the monthly average output and expected output of each cascade hydropower station used for allocation calculations are obtained. The average output represents electricity generation, and the expected output represents capacity. Both the projected output and the average output are output characteristic values ​​after deducting the forced output, used to obtain the output characteristic values ​​of the cascade power stations: The average output and expected output of each cascade hydropower station are summed to obtain the overall average output and expected output of the cascade, as shown below: In the formula: , The figures are the projected and average output of the entire cascade hydropower project in a given month, in MW; These are the serial numbers of the cascade hydropower stations. This refers to the number of cascade hydropower stations; , The first The projected and average monthly output (MW) of a cascade hydropower station; The overall force output process after achieving equilibrium: After balancing the cascade hydropower stations as a whole in the power system, the generation position of the entire cascade in terms of monthly power load and the hourly power output within the month are obtained. The sum of the forced output of each cascade hydropower station is then deducted to obtain the hourly power output of the entire cascade for allocation. ,in For the time of that month; The second step is to perform preliminary power output allocation calculations based on the proportion of electricity consumed: The overall hourly power generation output of the cascade hydropower stations, obtained after balancing, will be initially allocated according to the average monthly power output weight of each cascade hydropower station, as follows: In the formula: The first in the cascade hydropower project After the initial allocation of the hydropower stations, the first The output at all times, MW; If the output of each cascade hydropower station after allocation is less than or equal to the expected output for the month, that is... If the power output allocation is reasonable, the forced power output of each cascade hydropower station in that month is further superimposed to obtain the hourly power output process of each cascade hydropower station in the power system for that month, as follows: In the formula: The first in the cascade hydropower project The first hydropower station after the power system balance distribution The output at all times, MW; For the first The forced output of the hydropower station in that month was MW; The meaning of the result; The third step is the recalculation of output redistribution after the rationality assessment: If the output after the initial allocation in the second step is the same as the output allocated by any power station at any time... The output is greater than the power plant's expected output. ,Right now If the initial allocation result in the second step is unreasonable, the output needs to be recalculated. The calculation method is as follows: ① Calculate the monthly average power output rate of each cascade hydropower station. The calculation uses the average output rate after deducting forced output and the expected output rate. The cascade hydropower stations are then reordered from smallest to largest. The specific calculation is as follows: In the formula: To arrange by power output from smallest to largest Average power output of No. 1 power station; ② First, the power station ranked 1 is allocated. The expected output and average output of the power station 1 are divided into two parts. One part of the expected output and average output is placed in the overall power generation output of the cascade to balance the power, so that the average output rate of the remaining average output and expected output of the power station 1 is equal to the average output rate of the power station 2. The calculation for ② was obtained through trial and error. The trial and error method is as follows: To determine the partial output process of Power Station No. 1 as it gradually increases its output from zero to the expected value, the position at the top of the overall cascade output is located. The uppermost point of the overall output is then cut according to the expected output, and electricity is used to fill the upper output area. This yields the partial output process of Power Station No. 1 within the overall cascade output. When exerting effort in a certain anticipated manner If the average output of the remaining average output of Power Station No. 1 is equal to the average output calculated from the expected output, then the average output and expected output of the two parts can be obtained by trial calculation. The remaining average output and expected output of Power Station 1 are superimposed with those of Power Station 2 to form a new Power Station 2'. ③ For the new No. 2' power station, its allocation method is the same as that of No. 1 power station described in Part ②. The expected output and average output are divided into two parts. The power balance is carried out by using part of the expected output and average output in the remaining overall output of the cascade, so as to obtain the expected output of the No. 2' power station to find its position in the overall output of the cascade. and part of the power output process The remaining total output of the cascade needs to be reduced by the output already allocated to Power Station No. 1, so that the remaining average output of the new Power Station No. 2' is equal to the expected output. The calculated average output rate is equal to that of Power Station No.

3. The trial calculation method is the same as described in Part ② above. Then, the remaining average output and expected output of Power Station No. 2' are superimposed with those of Power Station No. 3 to form a new Power Station No. 3'. ④ By repeating the above steps one by one, the expected output of the new power station (n-1)' and the expected output of power stations 1 to (n-1) in the new power station (n-1)' can be obtained. At the same time, the partial output process of the new power station (n-1)' in finding its position and achieving equilibrium in the overall output of the cascade can be obtained. The average output and expected output of the remaining part of the (n-1)' power station are superimposed with the output of the n' power station to form a new n' power station. The total output of the remaining power source is... The allocation will be carried out in power plants 1 through n; ⑤ Further, based on the partial power output processes of power stations 1 and 2' to (n-1)' in the overall cascade power output, and the projected power outputs of power stations 1 to (n-1) in 2' to (n-1)' respectively, combined with the remaining projected power outputs of power stations 1 to (n-1) in the new power station n' and the remaining overall cascade power output, and also combined with the forced power output of each cascade hydropower station, the hourly power output process of each cascade hydropower station within the month, considering the cascade hydraulic connection, can be calculated after the power system's power balance is achieved. After obtaining the hourly power output process of each cascade hydropower station in the cascade hydropower station group within the month after the power system is balanced, the hourly power output process within the year can be obtained by calculating each month.

2. The method for calculating the power balance of a cascade hydropower station group in a power system according to claim 1, characterized in that: The projected output of Power Station 1, which is included in Power Station 2', and the projected output of Power Station 2' are calculated as follows: In the formula: The planned power output (MW) for Power Station 1, which is included in the new Power Station 2'; The projected output (MW) of Power Station No. 1 is used to locate its position in the overall power output of the cascade system. To contribute MW to the planned output of the new power station No. 2'; For the new power station No. 2', the expected output for finding a balance in the overall output of the cascade system. The projected output of both Power Station 1 and Power Station 2 can be calculated based on their respective proportions of the projected output of the new Power Station 2', as follows: In the formula, For sorting ( In the new power station No. 2', the expected output (MW) is used to first find the positional balance in the overall output of the cascade. The calculated projected output of the remaining power from power plants 1 and 2, to be used in conjunction with power plant 3 to form a new power plant 3', is as follows: In the formula, For sorting ( The projected output of power station ) in the new power station 3', MW; The expected output of Power Station No. 3 is obtained by superimposing the expected output of Power Station No. 3'. The specific formula is as follows: By repeating the trial calculation method described in Part ②, we can obtain the expected output of the new power station No. 3' in finding its position for balance in the overall output of the cascade. and part of the power output process ④ By repeating the above steps one by one, the expected output of the new power station (n-1)' and the expected output of power stations 1 to (n-1) in the new power station (n-1)' can be obtained. At the same time, the partial output process of the new power station (n-1)' in finding its position and achieving equilibrium in the overall output of the cascade can be obtained. The average output and expected output of the remaining part of the (n-1)' power station are superimposed with the output of the n' power station to form a new n' power station. The total output of the remaining power source is... The allocation will be carried out in power plants numbered 1 through n; Considering the hourly power output process within a month for the cascade hydraulic connection, the calculation formula is as follows: In the formula: To rank Power Station No. 1 after the power system balance distribution The output at all times, MW; After finding a position for balance in the overall output of the cascade power station No. 1, the [number]th [unit / stage] The output at all times, MW; for After finding its position and balancing its overall output across the cascade power station, the [number] power station... The output at all times, MW; For Power Station No. 1 The projected output of Power Station No. 1, in MW; for The projected output of Power Station No. 1 is MW; for No. 1 power station The projected output of Power Station No. 1, in MW; The remaining cascade stages as a whole when reaching the last power station in the sequence. MW (Power Utility) is constantly being exerted.

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