A method for analyzing power grid peak shaving demand considering grid structure

Abstract

A grid peak shaving demand analysis method of a grid structure is provided in the present application, which is proposed by considering the grid constraint and quantifying the system source and load supply and demand contradiction from the "source-grid-load" level more comprehensively, and optimizing the limited source and load supply and demand balance relationship. The most peak shaving demand is released through the peak shaving resource demand scheduling model, and the maximum accommodation space is generated through the peak shaving resource supply model, and then the total regional peak shaving resource supply and demand balance scheduling model is used to obtain the interconnection line interactive power, the interconnection system peak shaving power demand value and the interconnection system peak shaving capacity demand value. In order to make full use of the system peak shaving capacity and reduce the abandoned wind, the model considers the deep peak shaving effect of the unit to stabilize the safe operation of the grid. The present application can provide a peak shaving algorithm, reduce the abandoned wind as much as possible, and improve the grid peak shaving pressure. It has the advantages of scientific and reasonable, strong adaptability and good effect.

Description

Technical Field

[0001] This invention relates to the field of peak shaving in system grid structures, and is a method for analyzing the peak shaving demand of power grids that takes into account grid structures. Background Technology

[0002] Wind power output is characterized by randomness, volatility, and anti-peak-shaving issues. Therefore, large-scale grid connection of wind power poses a significant challenge to grid peak shaving and safe and stable operation. To address the prominent contradiction between system source and load, it is necessary to analyze and quantify the actual supply and demand contradiction of system source and load, and to calculate the grid peak-shaving demand under the existing peak-shaving resource operation conditions. However, current literature does not specifically study peak-shaving demand models and analysis methods based on the "source-grid-load" model. Instead, it focuses on optimizing the configuration of energy storage systems based on the specific peak-shaving requirements of the relevant grid to achieve optimal operation. As the primary step in the quantitative investigation of grid peak-shaving issues, conducting grid peak-shaving demand analysis considering the grid structure has important guiding significance. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a scientific, reasonable, applicable, and effective method for analyzing the peak-shaving demand of power grids that takes into account the grid structure.

[0004] The objective of this invention is achieved through the following technical solution: a method for analyzing the peak-shaving demand of a power grid considering the grid structure, characterized in that the method includes the following: 1) Constructing an equivalent interconnected system peak-shaving scheduling model Based on the analysis framework of the power grid peak-shaving demand mechanism and scheduling model considering the grid structure, an equivalent interconnected system peak-shaving scheduling model is constructed, namely: establishing a peak-shaving resource supply scheduling model, a peak-shaving resource demand scheduling model, and a total regional peak-shaving resource supply and demand balance scheduling model respectively. ① Peak-shaving resource demand scheduling model: With the maximum peak-shaving resource demand as the objective, release the maximum amount of peak-shaving demand; ② Peak-shaving resource supply scheduling model: With the goal of maximizing the supply of peak-shaving resources, it generates the largest possible acceptance space; ③ Overall regional peak-shaving resource supply and demand balance scheduling model: The difference period is obtained by using the peak-shaving demand set and demand period and the peak-shaving supply set and supply period. Then, iterative correction is carried out through peak-shaving supply and demand balance. Finally, the optimized tie-line interaction power, peak-shaving power demand value of interconnected system and peak-shaving capacity demand value of interconnected system are obtained at the intersection. 2) Optimize the objective function (a) Objective function of peak-shaving resource demand scheduling model Based on the maximum demand for peak-shaving resources The objective function is to release the maximum peak-shaving demand. The objective function is as follows: (1) (2) In the formula, For peak-shaving resource demand curve; Let the power flowing from B to A in the transmission line be defined as the positive direction; This represents the minimum technical output value for Unit B in Region B. Equivalent load curve for region B; (b) Objective function of peak-shaving resource supply scheduling model Maximum supply of peak-shaving resources The objective function is to generate the maximum accept space for peak-shaving demand, and its objective function is as follows: (3) (4) In the formula, For peak-shaving resource demand curve; This represents the power flowing from A to B along the transmission line. This represents the minimum technical output value for Unit A in Region A. Equivalent load curve for region A; 3) Optimization model solution method (a) Solution method for peak-shaving resource demand scheduling model From the preliminary calculation of the peak-shaving resource demand curve At the maximum value, the transmission line's maximum limit Downward peak-shaving resource supply power line ; Calculate when the peak-shaving resource demand power line is The set of peak-shaving resource requirements at that time is shown in Equation (5); (5) In the formula, - Power lines for peak shaving resources With curve The time intervals corresponding to the intersections; Equation (5) is used to determine whether the peak-shaving resource demand set exceeds the peak-shaving resource supply set. If it does, then let... Iterate until the constraints are met. The final output is a set of peak-shaving resource requirements. and peak demand periods - ; The iteration step size, A positive number close to 0; (b) Solution method for peak-shaving resource supply scheduling model From the preliminary calculation of the peak-shaving resource supply curve At the minimum value, the maximum value of the transmission line. Upward peak-shaving resource supply power line Calculate when the peak-shaving resource supply power line is The set of peak-shaving resource supply at that time is shown in Equation (6); (6) Equation (6) is used to determine whether the supply set of peak-shaving resources exceeds the demand set of peak-shaving resources. If it does, then let... Iterate until the constraints are met. The final output is a collection of peak-shaving resource supplies. and peak-shaving resource supply periods - ; 4) Constraints (a) System power balance constraints (7) In the formula, , and These are the actual output values ​​of thermal power units and wind power units, and the system load value, respectively. (b) Tie line power constraints (8) (c) Output constraints of thermal power units (9) In the formula, , For the first Minimum and maximum output values ​​of Taiwan's thermal power units For the region The Middle Actual output value of Taiwan thermal power units This represents the maximum power output of a thermal power unit. (d) Wind power output constraints (10) In the formula, , For the first Minimum and maximum output values ​​of typhoon generator units For the region The Middle Actual output value of the typhoon generator unit.

[0005] This invention presents a grid peak-shaving demand analysis method considering the grid structure. It comprehensively quantifies the source-load supply-demand contradiction at the "source-grid-load" level, taking into account grid constraints, and optimizes the constrained source-load supply-demand balance. It utilizes a peak-shaving resource demand scheduling model to release the maximum peak-shaving demand and a peak-shaving resource supply model to generate the maximum acceptance space. Then, it obtains the interconnection line interaction power, interconnected system peak-shaving power demand, and interconnected system peak-shaving capacity demand values ​​through a total regional peak-shaving resource supply-demand balance scheduling model. To more fully utilize the system's peak-shaving capacity and reduce wind curtailment, the model considers the deep peak-shaving effect of generating units to stabilize the safe operation of the grid. This invention provides a peak-shaving algorithm to minimize wind curtailment and improve grid peak-shaving pressure. It has the advantages of being scientifically sound, highly adaptable, and effective. Attached Figure Description

[0006] Figure 1 For example: A schematic diagram considering the impact of grid structure on power grid peak-shaving demand; Figure 2 For example: a schematic diagram of an interconnected power system structure; Figure 3 For: Time-series curve of peak power demand in interconnected systems; Figure 4 Here is a schematic diagram of the overall regional peak-shaving demand scheduling set of the interconnected system; Figure 5 Here is a framework diagram for analyzing a power grid peak-shaving and dispatching model that considers the power grid structure. Figure 6 For: Typical daily load and wind power data of the overall power system Figure 7 Here is a diagram showing the load and wind power data for Area A of the interconnected system. Figure 8 For example: Load and wind power data diagram for Area B of the interconnected system; Figure 9 Here is a schematic diagram of the overall power system's peak-shaving operation. Figure 10 For example: A schematic diagram considering the peak-shaving power demand of the interconnected system under the grid structure; Figure 11 For example: A diagram illustrating the peak-shaving power demand of the interconnected system; Figure 12 Here is a graph showing the cross-connection power curves under different tie-line power constraints. Figure 13 For example: Peak-shaving power demand curves of interconnected systems under different tie-line power constraints. Detailed Implementation

[0007] The following description, using accompanying drawings and implementation examples, further illustrates the power grid peak-shaving demand analysis method considering the grid structure proposed in this invention.

[0008] Reference Figure 1 , Figure 2 , Figure 3 Figure 4 and Figure 5 The present invention provides a method for analyzing the peak-shaving demand of a power grid considering the grid structure, comprising the following: 1) Construct an equivalent mutual system peak-shaving scheduling model To optimize the peak-shaving demand of the power grid while considering the grid structure and maximize the balance between power sources, grid, and loads, based on the aforementioned analysis framework of the peak-shaving demand mechanism and scheduling model considering the grid structure, peak-shaving resource supply scheduling model, peak-shaving resource demand scheduling model, and overall regional peak-shaving resource supply-demand balance scheduling model are established for the interconnected system constructed in two equivalent regions: ① Peak-shaving resource demand scheduling model: With the maximum peak-shaving resource demand as the objective, release the maximum amount of peak-shaving demand; ② Peak-shaving resource supply scheduling model: aiming to generate the maximum acceptance space with the maximum supply of peak-shaving resources as the objective; ③ Overall Regional Peak-Shaving Resource Supply-Demand Balance Scheduling Model: Difference time periods are derived by using the peak-shaving demand set and demand periods, as well as the peak-shaving supply set and supply periods. These differences are then iteratively corrected through peak-shaving supply-demand balance. Finally, the optimized tie-line interaction power, interconnected system peak-shaving power demand, and interconnected system peak-shaving capacity demand at the intersection are obtained.

[0009] 2) Optimize the objective function (a) Objective function of peak-shaving resource demand scheduling model Based on the maximum demand for peak-shaving resources The objective function is to release the maximum peak-shaving demand, as shown in equations (1) and (2).

[0010] (1) (2) In the formula, For peak-shaving resource demand curve; Let the power flowing from B to A in the transmission line be defined as the positive direction; This represents the minimum technical output value for Unit B in Region B. Equivalent load curve for region B.

[0011] (b) Objective function of peak-shaving resource supply scheduling model Maximum supply of peak-shaving resources The objective function is to generate the maximum peak demand acceptance space, as shown in equations (3) and (4).

[0012] (3) (4) In the formula, For peak-shaving resource demand curve; This represents the power flowing from A to B along the transmission line. This represents the minimum technical output value for Unit A in Region A. Equivalent load curve for region A; 3) Optimization model solution method (a) Solution method for peak-shaving resource demand scheduling model From the preliminary calculation of the peak-shaving resource demand curve At the maximum value, the transmission line's maximum limit Downward peak-shaving resource supply power line ; Calculate when the peak-shaving resource demand power line is The set of peak-shaving resource requirements at that time is shown in Equation (5).

[0013] (5) In the formula, - Power lines for peak shaving resources With curve The time interval corresponding to the intersection.

[0014] Equation (5) is used to determine whether the peak-shaving resource demand set exceeds the peak-shaving resource supply set. If it does, then let... ( Iterate for a step size (where the iteration step size is the step size) until the constraints are met. , It is a positive number close to 0. The final output is the set of peak-shaving resource requirements. and peak demand periods - .

[0015] (b) Solution method for peak-shaving resource supply scheduling model From the preliminary calculation of the peak-shaving resource supply curve At the minimum value, the maximum value of the transmission line. Upward peak-shaving resource supply power line .

[0016] Calculate when the peak-shaving resource supply power line is The set of peak-shaving resource supply at that time is shown in Equation (6).

[0017] (6) Equation (6) is used to determine whether the supply set of peak-shaving resources exceeds the demand set of peak-shaving resources. If it does, then let... Iterate until the constraints are met. The final output is a collection of peak-shaving resource supplies. and peak-shaving resource supply periods - .

[0018] 4) Constraints (a) System power balance constraints (7) In the formula, , and These represent the actual output values ​​of thermal power units and wind power units, and the system load values, respectively.

[0019] (b) Tie line power constraints (8) (c) Output constraints of thermal power units (9) In the formula, , For the first Minimum and maximum output values ​​of Taiwan's thermal power units For the region The Middle Actual output value of Taiwan thermal power units This represents the maximum power output of a thermal power unit.

[0020] (d) Wind power output constraints (10) In the formula, , For the first Minimum and maximum output values ​​of typhoon generator units For the region The Middle Actual output value of the typhoon generator unit.

[0021] The actual calculation uses a total installed capacity of 8712MW for thermal power units in the entire power system, with 4356MW installed capacity in both regions. The minimum output of each unit is set at 50%. Region A has a lower proportion of renewable energy and therefore less peak-shaving issues. Region B, however, has a high proportion of wind power penetration (30%), making peak-shaving more challenging. Relevant loads and operating parameters for both regions are provided below. Figure 6 , Figure 7 and Figure 8 .

[0022] By taking, for example Figure 9The overall power system peak-shaving operation shown indicates that the calculated peak-shaving power / electricity demand and wind curtailment rate are the same as those calculated for the interconnected system, verifying the equivalence of the analysis perspectives of the interconnected system and the overall power system.

[0023] Compared to the grid peak-shaving scenario without considering the grid structure, the system wind curtailment rate under the determined tie-line power constraint increases to 31.96%, according to... Figure 10 and Figure 11 The peak-shaving power and electricity demand curves of the interconnected system shown show that the peak-shaving power demand is 37349.3MW and the peak-shaving electricity demand is 9337.3MWh, which is an increase of 5.7% compared with the peak-shaving situation of the power grid without considering the grid structure.

[0024] from Figure 12 , 13 It can be seen that although the optimized coordination of power supplies in various regions of the interconnected system has alleviated the supply-demand balance and weakened the impact of grid constraints, resulting in an increase in peak-shaving supply space in region A to accommodate the greater demand released by region B as tie-line power constraints and interactive power increase, the peak-shaving power / capacity demand of the interconnected system gradually decreases. However, this still cannot change the reality that the increased peak-shaving demand caused by the increase in grid constraints. Therefore, it is necessary to further address this issue by adopting new regulation methods such as deep peak shaving of units and the application of energy storage technology.

[0025] Table 1 shows a comparison of peak-shaving variations in interconnected systems under different tie-line power constraints: Table 1. Comparison of Peak Shaving Variations in Interconnected Systems under Different Tie-Line Power Constraints

[0026] Table 1 shows that as the power limit of the tie line increases, the space for wind power acceptance in the interconnected system shrinks, and the wind curtailment rate continues to rise with a larger upward trend. Especially when the tie line power limit is 100MW, the wind curtailment rate reaches 33.3%, an increase of 10.2% compared to the case without considering the grid structure. This causes the expected peak-shaving power and capacity requirements of the interconnected system to gradually increase, reaching a maximum of 405.6MW and 101.4MWh, respectively. Therefore, compared to the increasingly large grid base, the impact of the grid structure on peak-shaving issues cannot be ignored.

[0027] The above analysis shows that the grid peak-shaving demand analysis method proposed in this invention, which considers the grid structure, can effectively reduce the wind curtailment rate and ensure the stable and safe operation of the system. It also has greater reference value for future combined thermal and wind power generation.

[0028] The calculation conditions, illustrations, tables, etc. in the embodiments of this invention are only used to further illustrate the invention and are not exhaustive. They do not constitute a limitation on the scope of protection of the claims. Those skilled in the art, based on the inspiration gained from the embodiments of this invention, can conceive of other substantially equivalent alternatives without creative effort, all of which are within the scope of protection of this invention.

Claims

1. A method for analyzing peak-shaving demand in a power grid considering its grid structure, characterized in that, The method Includes the following: 1) Constructing an equivalent interconnected system peak-shaving scheduling model Based on the analysis framework of the power grid peak-shaving demand mechanism and scheduling model considering the grid structure, an equivalent interconnected system peak-shaving scheduling model is constructed, namely: establishing a peak-shaving resource supply scheduling model, a peak-shaving resource demand scheduling model, and a total regional peak-shaving resource supply and demand balance scheduling model respectively. ① Peak-shaving resource demand scheduling model: With the maximum peak-shaving resource demand as the objective, release the maximum amount of peak-shaving demand; ② Peak-shaving resource supply scheduling model: With the goal of maximizing the supply of peak-shaving resources, it generates the largest possible acceptance space; ③ Overall regional peak-shaving resource supply and demand balance scheduling model: The difference period is obtained by using the peak-shaving demand set and demand period and the peak-shaving supply set and supply period. Then, iterative correction is carried out through peak-shaving supply and demand balance. Finally, the optimized tie-line interaction power, peak-shaving power demand value of interconnected system and peak-shaving capacity demand value of interconnected system are obtained at the intersection. 2) Optimize the objective function (a) Objective function of peak-shaving resource demand scheduling model Based on the maximum demand for peak-shaving resources The objective function is to release the maximum peak-shaving demand. The objective function is as follows: (1) (2) In the formula, For peak-shaving resource demand curve; Let the power flowing from B to A in the transmission line be defined as the positive direction; This represents the minimum technical output value for Unit B in Region B. Equivalent load curve for region B; (b) Objective function of peak-shaving resource supply scheduling model Maximum supply of peak-shaving resources The objective function is to generate the maximum accept space for peak-shaving demand, and its objective function is as follows: (3) (4) In the formula, For peak-shaving resource demand curve; This represents the power flowing from A to B along the transmission line. This represents the minimum technical output value for Unit A in Region A. Equivalent load curve for region A; 3) Optimization model solution method (a) Solution method for peak-shaving resource demand scheduling model From the preliminary calculation of the peak-shaving resource demand curve At the maximum value, the transmission line's maximum limit. Downward peak-shaving resource supply power line ; Calculate when the peak-shaving resource demand power line is The set of peak-shaving resource requirements at that time is shown in Equation (5); (5) In the formula, - Power lines for peak shaving resources With curve The time intervals corresponding to the intersections; Determine whether the aforementioned peak-shaving resource demand set exceeds the peak-shaving resource supply set. If it does, then let... Iterate until the constraints are met. The final output is a set of peak-shaving resource requirements. and peak demand periods - ; The iteration step size, A positive number close to 0; (b) Solution method for peak-shaving resource supply scheduling model From the preliminary calculation of the peak-shaving resource supply curve At the minimum value, the maximum value of the transmission line. Upward peak-shaving resource supply power line Calculate when the peak-shaving resource supply power line is The set of peak-shaving resource supply at that time is shown in Equation (6); (6) Determine whether the aforementioned peak-shaving resource supply set exceeds the peak-shaving resource demand set. If it does, then let... Iterate until the constraints are met. The final output is a collection of peak-shaving resource supplies. and peak-shaving resource supply periods - ; 4) Constraints (a) System power balance constraints (7) In the formula, , and These are the actual output values ​​of thermal power units and wind power units, and the system load value, respectively. (b) Tie line power constraints (8) (c) Output constraints of thermal power units (9) In the formula, , For the first Minimum and maximum output values ​​of Taiwan's thermal power units For the region The Middle Actual output value of Taiwan thermal power units This represents the maximum power output of a thermal power unit. (d) Wind power output constraints (10) In the formula, , For the first Minimum and maximum output values ​​of typhoon generator units For the region The Middle Actual output value of the typhoon generator unit.

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