Energy storage power duration curve estimation method

Abstract

The application discloses a kind of energy storage power duration curve estimation methods, specifically according to the following steps implementation: according to the planning level year load, wind power, photovoltaic output time series, conventional unit maximum, minimum adjustable, calculate new energy blocked output;Through day minimum energy storage capacity, calculate energy storage capacity minimum point, through minimum energy storage power and energy storage charge-discharge constraint condition, calculate energy storage capacity maximum point;Through energy storage capacity maximum point and minimum point, obtain energy storage power duration curve;According to the planning level year new energy utilization rate calculation error requirement, obtain equivalent energy storage capacity maximum value, obtain energy storage power duration approximate curve.The method disclosed by the application, by the calculation of equivalent energy storage capacity maximum point and energy storage capacity minimum point, can effectively explain the equivalent efficacy of various energy storage technologies in meeting new energy utilization rate index, and provides a theoretical analysis tool for the rational planning of various energy storage technologies.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology and relates to a method for estimating the duration curve of energy storage power. Background Technology

[0002] Accelerating the construction of a new power system dominated by new energy sources and gradually increasing the proportion of new energy is an inherent requirement for achieving carbon peaking and carbon neutrality. As the installed capacity of new energy sources continues to increase while the installed capacity of conventional power sources such as thermal power gradually decreases, system flexibility resources are becoming increasingly scarce. To achieve a balance between power generation and consumption and solve the problem of power shifting in time and space, improving system flexibility through energy storage is an inevitable trend in the development of new power systems. Energy storage, as one of the important technologies and basic equipment for building new power systems, can significantly improve the system's power regulation and capacity support capabilities through reasonable allocation of energy storage scale. Therefore, conducting research on the relationship between energy storage and power duration in power systems, thereby providing scientific planning for the overall configuration of energy storage capacity in power systems, is of great significance.

[0003] Currently, the calculation of energy storage capacity, energy storage power, and energy storage duration in systems containing new energy sources faces the following problems: Given a clear new energy utilization rate target, the most widely used method is to repeatedly calculate the energy storage capacity to meet the given new energy utilization target using time-series or stochastic production simulations. On the one hand, this method relies on repeated production simulation optimization, resulting in time-consuming and repetitive calculations, often leading to over-sizing of energy storage capacity, and failing to fully utilize the statistical characteristics of new energy curtailment. On the other hand, this method cannot obtain a quantitative relationship between energy storage power and duration, causing considerable inconvenience for subsequent system electricity cost analysis. More importantly, the same new energy utilization rate target can be achieved with different energy storage capacities, necessitating the use of the relationship between energy storage power and duration curves to guide the rational planning of energy storage capacity. Summary of the Invention

[0004] The purpose of this invention is to provide a method for estimating the energy storage power duration curve. This method proposes an energy storage power duration curve estimation method by calculating the minimum and maximum points of the energy storage capacity of the power system. Furthermore, by reasonably selecting the energy storage capacity, the power supply needs of the power system can be met.

[0005] The technical solution adopted in this invention is a method for estimating the duration curve of energy storage power, which specifically includes the following steps:

[0006] Step 1: Based on the planned annual load, wind power, and photovoltaic power output time series, and the maximum and minimum adjustable capacity of conventional units, calculate the power output of renewable energy sources under obstruction.

[0007] Step 2: Calculate the minimum energy storage capacity based on the minimum daily energy storage capacity required to meet the new energy utilization rate target.

[0008] Step 3: Calculate the maximum energy storage capacity point based on the minimum daily energy storage power that meets the new energy utilization rate index.

[0009] Step 4: Obtain the energy storage power duration curve function based on the maximum and minimum points of the energy storage capacity;

[0010] Step 5: Based on the error requirements of the system's new energy utilization rate index, the maximum point of the equivalent energy storage capacity is obtained, and the approximate curve of energy storage power duration is obtained.

[0011] The invention is further characterized by:

[0012] The specific process of step 1 is as follows:

[0013] Step 1.1 proposes a novel power system abandonment mechanism based on the net load curve, specifically as follows:

[0014] For systems with access to new energy sources, the power generation and consumption constraints that must be met during operation are shown in the following formula (1):

[0015] p gen (t)+p new (t)=p l (t) (1);

[0016] Where, p gen (t) represents the output of the conventional unit, p l (t) represents the original load output, p gen (t) represents the output of new energy sources;

[0017] Define the net load curve as The value is the original load curve minus the new energy curve p. new(t) As shown in formula (2) below:

[0018]

[0019] From the perspective of renewable energy consumption, the reason for the curtailment of electricity is that the minimum output of conventional units is greater than the net load curve, as shown in the following formula (3):

[0020]

[0021] Where, p gen,min This indicates the minimum adjustable force of a conventional unit.

[0022] Step 1.2, calculate the power output of the new energy source under obstruction, specifically as follows:

[0023] Let p be the output of the new energy source when it is blocked. new,lose (t), at a certain moment, the power of the new energy source is blocked as shown in the following formula (4):

[0024]

[0025] The specific process of step 2 is as follows:

[0026] Step 2.1, calculate the minimum daily energy storage capacity to meet the utilization rate of new energy sources, specifically:

[0027] Let the system calculation or sampling step size be ΔT, and let Q be the daily blocked power of the new energy source. new,lose (t), then the amount of renewable energy wasted on a certain day is Q. new,lose As shown in formula (5) below:

[0028]

[0029] Where T is the length of a day, the daily abandoned electricity in a year is obtained by formula (5) and sorted in ascending order to obtain the annual abandoned electricity curve of new energy. Let the energy storage capacity in the system be S, and the theoretical annual power generation of the new energy source be Q. new Then the new energy utilization rate η can be obtained from formulas (6) to (8):

[0030]

[0031]

[0032]

[0033] Where, p new Let D be the daily power generation from renewable energy sources, and N be the number of days in a year and the length of a year, given a renewable energy consumption target. Based on this, let S be the minimum daily energy storage capacity required to meet the utilization rate of new energy sources. new,lose，min We can obtain the following from formula (9):

[0034]

[0035] Step 2.2, solve for the minimum point of the system's energy storage capacity, specifically:

[0036] Define the minimum energy storage capacity S min To calculate the step size ΔT and the maximum energy storage power point P s,max The point is defined here, with coordinates [ΔT, P]. s,max This is called the minimum point of energy storage capacity, as shown in formula (10):

[0037] S min =ΔT×P s,max (10);

[0038] At sampling time ΔT = 1, the energy storage capacity S obtained by equation (9) new,lose，minThis represents the minimum energy storage capacity and the maximum energy storage power, P. s,max Numerically, this represents the minimum energy storage capacity.

[0039] S min =S new,lose，min (11);

[0040] P s,max =S new,lose，min (12).

[0041] The specific process of step 3 is as follows:

[0042] Step 3.1, calculate the minimum energy storage capacity required to meet the needs of renewable energy consumption, specifically:

[0043] By analyzing the 8760 curve of blocked power from renewable energy sources and arranging the curves in ascending order, we obtain the annual blocked power duration curve for renewable energy sources. Let the energy storage capacity be P. s The minimum energy storage capacity required to meet the needs of renewable energy consumption is P. s,new,min It satisfies formulas (13) and (14):

[0044]

[0045]

[0046] Step 3.2, solve for the minimum daily energy storage duration corresponding to the minimum energy storage capacity, specifically:

[0047] For new energy systems without internal network constraints, considering energy storage facilities to be charged and discharged daily, the main constraints are:

[0048] The energy storage charging and discharging power constraints are as follows:

[0049] 0≤P ch ≤P s,R (15);

[0050] 0≤P disch ≤P s,R (16);

[0051] In the formula: P ch P is the equivalent charging power of energy storage in the system. disch P is the equivalent discharge power. s,R This is the equivalent rated power;

[0052] The daily charging capacity constraints for energy storage are as follows:

[0053]

[0054] In the formula: δ represents the overall charging and discharging efficiency of the energy storage device;

[0055] The annual charge and discharge capacity constraints for energy storage are as follows:

[0056]

[0057] By combining equations (13)-(18), we can obtain the minimum energy storage duration T that satisfies the given new energy utilization rate index. s,new,min :

[0058]

[0059] Step 3.3, solve for the maximum point of the system's energy storage capacity, specifically:

[0060] Define the maximum energy storage capacity S max Minimum energy storage capacity P s,min And the maximum energy storage duration T s,max As shown in formula (20), the coordinate point [T] is now determined. s,max ,P s,min This is called the energy storage capacity maxima point.

[0061] S max =T s,max ×P s,min (20);

[0062] Obviously, the minimum energy storage power P s,min And the maximum point of energy storage duration T s,max This can be represented as (21) and (22):

[0063] P s,min =P s,new,min (twenty one);

[0064] T s,max =T s,new,min (twenty two).

[0065] The specific process of step 4 is as follows:

[0066] Since the energy storage power that meets certain new energy utilization rate indicators decreases with the increase of energy storage time, the power value for each duration is obtained by multiple calculations using the following formula (23):

[0067]

[0068] The specific process of step 5 is as follows:

[0069] The capacity corresponding to the improved minimum energy storage power is redefined as the equivalent maximum energy storage value, expressed as:

[0070] S max,eq =T s,max,eq ×P s,min,eq (twenty four);

[0071] In the formula: T s,max,eq P represents the equivalent maximum energy storage duration. s,min,eq The equivalent minimum energy storage power is then expressed as:

[0072]

[0073] If the maximum energy storage capacity is greater than the minimum equivalent energy storage capacity, and the difference between the two is:

[0074] σ=S max -S min (26);

[0075] When the difference σ is small, the energy storage power duration function relationship can be approximated as:

[0076]

[0077] Let S be the energy storage capacity configured in the system. max,eq After approximation, the daily increase in energy storage capacity can be fully charged, and the utilization rate of new energy sources is closer to the target utilization rate. The largest partial quantity is denoted as κ, and is represented as

[0078]

[0079] In the planning process, it is required that [ΔT,T] s,max,eq If the deviation κ between the calculated new energy utilization rate and the actual utilization rate for the energy storage capacity configured in the interval is no greater than θ percentage points, then by using equation (28), the condition for satisfying equation (27) can be obtained as follows:

[0080]

[0081] Setting the equation in formula (29) to equality, we obtain the equivalent maximum energy storage duration T. s,max,eq and equivalent minimum energy storage power P s,min,eq ;

[0082] As can be seen from equation (29), as the amount of new energy power generation in the system increases, the difference between the maximum and minimum allowable energy storage capacity increases, that is, the applicability of equation (27) is better.

[0083] The beneficial effects of this invention are as follows:

[0084] 1. The method proposed in this invention can quickly obtain an approximate curve function of the energy storage power duration curve by calculating the maximum and minimum points of energy storage capacity. For the first time, the above relationship is quantified in the form of a mathematical expression. Its principle is intuitive, easy to understand, has good applicability, and is easy to calculate.

[0085] 2. The method proposed in this invention can guide the planning and configuration of energy storage capacity at the level of new energy power plants, as well as in municipal, provincial, and regional power grids containing new energy sources. It is of great significance for improving the level of new energy consumption, meeting the power system's supply security requirements, and promoting the healthy and sustainable development of the energy storage industry.

[0086] 3. The method proposed in this invention can effectively illustrate the equivalent efficacy of various energy storage technologies in meeting the new energy utilization rate indicators, without deliberately requiring energy storage technologies to reach a specified energy storage duration. This helps various energy storage technologies to give full play to their respective special effects, provides theoretical analysis means for the rational planning of various energy storage technologies, and provides quantitative analysis methods for reducing the energy storage configuration cost of power systems. Attached Figure Description

[0087] Figure 1 This is a flowchart of the energy storage power duration curve estimation method of the present invention;

[0088] Figure 2 This is an illustration of the mechanism of new energy curtailment based on the net load curve in a new type of power system with new energy as the main body, proposed by the energy storage power duration curve estimation method of this invention;

[0089] Figure 3 This is a schematic diagram illustrating the calculation of the minimum daily energy storage capacity that meets the new energy utilization rate index, proposed by the energy storage power duration curve estimation method of this invention.

[0090] Figure 4 This is a schematic diagram illustrating the calculation of the minimum energy storage power required to meet the utilization rate of new energy, as proposed by the energy storage power duration curve estimation method of this invention.

[0091] Figure 5 This is an illustration of the energy storage power duration estimation method proposed in this invention, which calculates the energy storage power duration estimation curve by using the maximum and minimum points of energy storage capacity.

[0092] Figure 6 This is a diagram illustrating the difference between the energy storage power duration curve that actually meets the new energy utilization index proposed by the energy storage power duration curve estimation method of this invention and the energy storage power duration curve proposed by the estimation method.

[0093] Figure 7 This invention provides an energy storage power duration curve that simultaneously meets the new energy utilization rate index and the system supply guarantee requirements, based on the energy storage power duration curve estimation method proposed in this invention. Detailed Implementation

[0094] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0095] This invention presents a method for estimating the energy storage power duration curve. Based on meeting the requirements of new energy utilization rate indicators, it proposes a method for estimating the energy storage power duration curve, the process of which is as follows: Figure 1 As shown, the specific steps are as follows:

[0096] Step 1: Based on the curtailment mechanism of the new power system, calculate the curtailed power of the system; based on the planned annual load, wind power, and photovoltaic output time series, and the maximum and minimum adjustable capacity of conventional units, analyze the curtailment mechanism based on the net load curve, and calculate the hindered output of new energy sources. The mechanism is detailed in [link to relevant documentation]. Figure 2 As shown.

[0097] Step 1.1 proposes a novel power system abandonment mechanism based on the net load curve:

[0098] For systems with access to new energy sources, the power generation and consumption constraints that must be met during operation are given by equation (1). Where p gen (t) represents the output of the conventional unit, p l (t) represents the original load output, p gen (t) represents the output of new energy sources.

[0099] p gen (t)+p new (t)=p l (t) (1);

[0100] Define the net load curve as Its value is the original load curve minus the new energy curve, as shown in formula (2).

[0101]

[0102] From the perspective of renewable energy consumption, the reason for power curtailment is that the minimum output of conventional generating units is greater than the net load curve, which can be expressed as formula (3). gen,min This indicates the minimum adjustable value for a conventional unit.

[0103]

[0104] Step 1.2, Calculate the power output of the new energy source under obstruction.

[0105] Optionally, let p be the output power of the new energy source when it is blocked. new,lose (t), the power of the new energy source is blocked at a certain moment, which can be expressed as formula (4).

[0106]

[0107] Step 2: Calculate the minimum daily energy storage capacity based on the minimum daily energy storage capacity required to meet the renewable energy utilization rate target; plot the annual continuous curve of daily renewable energy curtailment using the renewable energy obstruction power curve, then calculate the minimum daily energy storage capacity required to meet the renewable energy utilization rate target, and calculate the minimum energy storage capacity point. The mechanism is described in [link to article]. Figure 3 As shown.

[0108] Step 2.1, calculate the minimum daily energy storage capacity to meet the renewable energy utilization rate:

[0109] Let the system calculation or sampling step size be ΔT (this invention calculates based on 1 hour, and the calculation step size can be further reduced as needed). The blocked power output of new energy sources for 8760 hours throughout the year is calculated to obtain the blocked power curve of new energy sources. Let Q be the daily blocked power output of new energy sources. new,lose If (t), then the amount of renewable energy abandoned on a certain day can be expressed as formula (5).

[0110]

[0111] (5) In the formula: T is the length of a day. The daily amount of abandoned electricity in a year is obtained by using formula (5) and sorted in ascending order to obtain the annual abandoned electricity curve of new energy. Let the energy storage capacity in the system be S, and the theoretical annual power generation of the new energy source be Q. new Then the utilization rate of new energy η can be obtained by formula (6).

[0112]

[0113]

[0114]

[0115] In equations (6) and (7), D is the number of days in a year, and N is the length of a year. Given a new energy consumption target... Based on this, let S be the minimum daily energy storage capacity required to meet the utilization rate of new energy sources. new,lose，min Its value can be obtained by formula (9).

[0116]

[0117] Step 2.2, Solve for the minimum point of the system's energy storage capacity.

[0118] Define the minimum energy storage capacity S min To calculate the step size ΔT and the maximum energy storage power point P s,max The point is defined here, with coordinates [ΔT, P]. s,max This is called the minimum point of energy storage capacity, as shown in formula (10).

[0119] S min =ΔT×P s,max (10);

[0120] Its physical meaning is: if the energy storage capacity is at its minimum value, within the time interval [0, ΔT], the energy storage power is greater than or equal to P. s,maxUnder these conditions, the utilization rate of new energy sources does not change with the increase of energy storage power; that is, the product of energy storage power and duration is always equal to the minimum value of energy storage capacity, forming an inverse proportional function.

[0121] Obviously, when the sampling time ΔT = 1, the energy storage capacity S obtained by equation (9) is... new,lose，min This represents the minimum energy storage capacity and the maximum energy storage power, P. s,max Numerically, this represents the minimum energy storage capacity.

[0122] S min =S new,lose，min (11);

[0123] P s,max =S new,lose，min (12);

[0124] Step 3: Calculate the maximum energy storage capacity point based on the minimum daily energy storage power required to meet the renewable energy utilization rate target; plot the annual continuous curve of renewable energy obstruction power using the renewable energy obstruction power curve, calculate the minimum energy storage power required to meet the renewable energy utilization rate, and calculate the maximum energy storage capacity point. The principle is explained in [link to article]. Figure 4 As shown:

[0125] Step 3.1: Calculate the minimum energy storage capacity required to meet the needs of renewable energy consumption.

[0126] By arranging the 8760 curves of blocked power from renewable energy sources in ascending order, we obtain the annual blocked power duration curve for renewable energy sources. Let the energy storage capacity be P. s The minimum energy storage capacity required to meet the needs of renewable energy consumption is P. s,new,min It satisfies formulas (13) and (14).

[0127]

[0128]

[0129] Step 3.2: Solve for the minimum daily energy storage duration corresponding to the minimum energy storage capacity;

[0130] For new energy systems without internal network constraints, considering energy storage facilities to be charged and discharged daily, the main constraints are:

[0131] Energy storage charging and discharging power constraints:

[0132] 0≤P ch ≤P s,R (15);

[0133] 0≤P disch ≤P s,R (16);

[0134] In the formula: P ch P is the equivalent charging power of energy storage in the system. disch P is the equivalent discharge power. s,R This is the equivalent rated power.

[0135] Energy storage daily charging capacity constraint

[0136]

[0137] In the formula: δ represents the overall charging and discharging efficiency of the energy storage device.

[0138] Annual charge and discharge capacity constraints for energy storage

[0139]

[0140] By combining equations (13)-(18), the minimum energy storage duration T that satisfies the given new energy utilization rate index can be obtained. s,new,min .

[0141]

[0142] Step 3.3, solve for the maximum energy storage capacity of the system:

[0143] Define the maximum energy storage capacity S max Minimum energy storage capacity P s,min And the maximum energy storage duration T s,max As shown in formula (20), the coordinates [T] are determined here. s,max ,P s,min This is called the maximum energy storage capacity point.

[0144] S max =T s,max ×P s,min (20);

[0145] Its physical meaning is that, given a fixed minimum energy storage power, there must be a correspondingly large energy storage duration T. s,max , by P s,min and T s,max The determined energy storage capacity meets the requirements of the new energy utilization rate index, and the energy storage duration is greater than T. s,max Under these circumstances, the utilization rate of new energy sources remains unchanged.

[0146] Obviously, the minimum energy storage power P s,min And the maximum point of energy storage duration T s,max This can be represented as (21) and (22).

[0147] P s,min =P s,new,min (twenty one);

[0148] T s,max =T s,new,min (twenty two);

[0149] It should be noted that the maximum energy storage capacity can be calculated by using the minimum energy storage power required to meet the utilization rate of new energy sources. In practice, since the minimum energy storage capacity corresponding to the consumption of new energy sources is relatively small and the energy storage duration is relatively long, the maximum energy storage capacity can be calculated by using the energy storage power corresponding to the supply guarantee demand or by controlling the maximum energy storage duration to about 6-8 hours (currently, the configuration duration of electrochemical energy storage is generally about 2-4 hours and pumped storage is about 6-8 hours).

[0150] Step 4: Based on the maximum and minimum energy storage capacity points, propose the functional relationship of the energy storage power-duration curve; based on the maximum and minimum energy storage capacity points determined in Steps 2 and 3 that meet the requirements of new energy utilization indicators, obtain the energy storage power-duration curve. The principle is as follows: Figure 5 As shown.

[0151] Generally, the energy storage power that meets a certain new energy utilization rate index decreases as the energy storage duration increases (it should be noted that a certain energy storage power corresponds to a minimum energy storage duration, and the energy storage capacity determined by the product of the two is the minimum capacity that meets the given new energy utilization rate. Therefore, the energy storage power-duration function relationship mentioned here is actually the lower boundary point that meets the new energy utilization rate index. Points located above the energy storage power-duration curve are all points that meet the index. The function relationship in this paper refers to the lower boundary). The relationship between the two is constrained by many factors, and the power value under each duration can only be calculated multiple times, as shown in equation (23):

[0152]

[0153] In the three-piece function of formula (23):

[0154] First paragraph: When the energy storage duration is between [0, ΔT], the energy storage power duration forms an inverse proportional function, and the product of the two is equal to the minimum point of the energy storage capacity.

[0155] Second paragraph: Energy storage duration is located in [ΔT, T] s,max When the value is between ], it can be obtained by solving formulas (15)-(19). The corresponding minimum energy storage time can be obtained by solving different energy storage powers to form a set of lower boundary values. The calculation process is complicated and time-consuming.

[0156] Third paragraph: Energy storage duration is located in [T] s,max When the value is between [+∞], the energy storage power does not change with the energy storage duration and remains at the minimum energy storage power, which is a straight line.

[0157] Step 5: Based on the error requirements of the system's new energy utilization rate index, the maximum point of the equivalent energy storage capacity is obtained, resulting in an approximate curve of energy storage power duration. Furthermore, the applicability of the curve is expanded to meet the power system's supply guarantee needs. The principle is explained in [link to article]. Figure 6 As shown.

[0158] The energy storage capacity determined by the minimum energy storage power is generally too large, and the actual energy storage capacity at the configuration point is often much smaller than the maximum energy storage capacity. Therefore, it is necessary to increase the minimum energy storage power and reduce the energy storage capacity configuration. The capacity corresponding to the increased minimum energy storage power is then redefined as the equivalent maximum energy storage value, expressed as:

[0159] S max,eq =T s,max,eq ×P s,min,eq (twenty four);

[0160] In the formula: T s,max,eq P represents the equivalent maximum energy storage duration. s,min,eq Equivalent minimum energy storage capacity.

[0161] Then equation (23) can be expressed as

[0162]

[0163] Generally, the maximum energy storage capacity is greater than the minimum equivalent energy storage capacity. If the difference between the two is...

[0164] σ=S max -S min (26);

[0165] When the difference σ is small, the energy storage power-duration function relationship can be approximated as follows:

[0166]

[0167] Obviously, when the energy storage duration is in the range [ΔT, T] s,max,eq When the energy storage capacity is between 1 / 2 and 2 / 3, the new energy utilization rate calculated using equation (27) is relatively higher than the actual utilization rate. Let S be the energy storage capacity configured in the system. max,eq After approximation, the daily increase in energy storage capacity can be fully charged. The maximum deviation of the new energy utilization rate from the target utilization rate η is denoted as κ, and expressed as...

[0168]

[0169] In the planning process, it is required that [ΔT,T] s,max,eq If the deviation κ between the calculated new energy utilization rate and the actual utilization rate for the energy storage capacity configured in the interval is no greater than θ percentage points, then by using equation (28), the condition for satisfying equation (27) can be obtained as follows:

[0170]

[0171] In Order (29) The equivalent maximum energy storage duration T can be obtained. s,max,eq and equivalent minimum energy storage power P s,min,eq .

[0172] As can be seen from equation (29), as the amount of new energy power generation in the system increases, the difference between the maximum and minimum allowable energy storage capacity increases, that is, the applicability of equation (27) is better.

[0173] The emphasis here is that although equation (27) is for obtaining the energy storage power-duration relationship to meet the new energy utilization rate index, it is only necessary to meet the minimum energy storage capacity required for system supply guarantee of S. l,gap，min and minimum energy storage power P l,gap,min Including the energy storage power duration curve obtained above, equation (24) can be extended to an energy storage power duration curve that simultaneously meets the new energy utilization rate index and the system supply guarantee requirements. This is crucial for the energy storage capacity configuration of a new power system with new energy as the main body. The principle is explained in [link to relevant documentation]. Figure 7 As shown.

Claims

1. A method for estimating the duration curve of energy storage power, characterized in that: Specifically, the steps include the following: Step 1: Based on the planned annual load, wind power, and photovoltaic power output time series, and the maximum and minimum adjustable capacity of conventional units, calculate the power output of renewable energy sources under obstruction. Step 2: Calculate the minimum energy storage capacity based on the minimum daily energy storage capacity required to meet the new energy utilization rate target. Step 3: Calculate the maximum energy storage capacity point based on the minimum daily energy storage power that meets the new energy utilization rate index. Step 4: Obtain the energy storage power duration curve function based on the maximum and minimum points of the energy storage capacity; the specific process of step 4 is as follows: Since the energy storage power that meets certain new energy utilization rate indicators decreases with the increase of energy storage time, the power value for each duration is obtained by multiple calculations using the following formula (1): （1）； in, This represents the stored energy power at time t. This indicates the maximum energy storage duration. Indicates the minimum energy storage capacity. The step size is represented by t, and the time interval is represented by t. Step 5: Based on the error requirements of the system's new energy utilization rate index, obtain the maximum point of the equivalent energy storage capacity, and obtain the approximate curve of energy storage power duration; the specific process of step 5 is as follows: redefine the capacity corresponding to the minimum energy storage power after the improvement as the maximum value of the equivalent energy storage, expressed as: （2）； In the formula: Indicates the equivalent maximum energy storage duration. The equivalent minimum energy storage power is then expressed as: （3）； If the maximum energy storage capacity is greater than the minimum equivalent energy storage capacity, and the difference between the two is: （4）； When the difference When the value is relatively small, the energy storage power duration function relationship is approximately as follows: （5）； Assume the system is configured with energy storage capacity. After approximation, the daily increase in energy storage capacity can be fully charged, and the utilization rate of new energy sources is closer to the target utilization rate. The largest partial large quantity is denoted as , represented as （6）； Where D is the number of days in a year. This represents the theoretical annual power generation from new energy sources; In the planning process, it is required that... Deviation between the calculated renewable energy utilization rate and the actual utilization rate for energy storage capacity configured in the interval Not greater than If the percentage point is 1, then through equation (6), the condition for satisfying equation (5) is: （7）； Setting the equation in formula (7) to equality, we obtain the equivalent maximum energy storage duration. and equivalent minimum energy storage power As shown in equation (7), as the amount of new energy power generation in the system increases, the difference between the maximum and minimum allowable energy storage capacity increases, which means that the applicability of equation (5) is better.

2. The method for estimating the energy storage power duration curve according to claim 1, characterized in that: The specific process of step 1 is as follows: Step 1.1 proposes a novel power system abandonment mechanism based on the net load curve, specifically as follows: For systems with access to new energy sources, the power generation and consumption constraints that must be met during operation are shown in the following formula (8): （8）； in, This indicates the output of the conventional generating unit. Indicates the output of the original load. This indicates the contribution of new energy sources; Define the net load curve as , The value is the original load output curve minus the new energy output curve. As shown in the following formula (9): （9）； From the perspective of renewable energy consumption, the reason for the curtailment of electricity is that the minimum output of conventional generating units is greater than the net load curve, as shown in the following formula (10): （10）； in, This indicates the minimum output of a conventional unit; Step 1.2, calculate the power output of the new energy source under obstruction, specifically as follows: Record the obstruction of new energy power output At a certain moment, the output of new energy sources was hindered. As shown in the following formula (11): （11）。 3. The method for estimating the energy storage power duration curve according to claim 2, characterized in that: The specific process of step 2 is as follows: Step 2.1, calculate the minimum daily energy storage capacity to meet the utilization rate of new energy sources, specifically: Let the system calculation or sampling step size be... Record the daily power consumption of new energy sources as Then, the amount of renewable energy wasted on a certain day As shown in the following formula (12): （12）； in, T The length of a day is used to calculate the daily amount of abandoned electricity in a year using formula (12) and sort them in ascending order to obtain the annual abandoned electricity curve of new energy. Let the energy storage configuration capacity in the system be . S The theoretical annual power generation of new energy sources is Then the utilization rate of new energy We can obtain the following from formulas (13) to (15): （13）； （14）； （15）； in, This is the daily power generation from new energy sources. D It is the number of days in a year. N It is a one-year period, given a target for renewable energy consumption. Based on this, the minimum daily energy storage capacity required to meet the utilization rate of new energy sources is denoted as... The result can be obtained from formula (16): （16）； Step 2.2, solve for the minimum point of the system's energy storage capacity, specifically: Define the minimum value of energy storage capacity To calculate the step size and the maximum point of energy storage power A definite point, here the coordinates of the point. This is called the minimum point of energy storage capacity, as shown in formula (17): （17）； At sampling time When, the energy storage capacity obtained by equation (16) This represents the minimum energy storage capacity and the maximum energy storage power. Numerically, this represents the minimum energy storage capacity. （18）； （19）。 4. The method for estimating the energy storage power duration curve according to claim 3, characterized in that: The specific process of step 3 is as follows: Step 3.1, calculate the minimum energy storage capacity required to meet the needs of renewable energy consumption, specifically: By analyzing the 8760 curve of blocked power from renewable energy sources and arranging the curves in ascending order, we obtain the annual blocked power duration curve for renewable energy sources. Let the energy storage capacity be denoted as The minimum energy storage capacity required to meet the needs of new energy consumption is It satisfies formulas (20) and (21): （20）； （21）； Step 3.2, solve for the minimum daily energy storage duration corresponding to the minimum energy storage capacity, specifically: For new energy systems without internal network constraints, considering energy storage facilities to be charged and discharged daily, the main constraints are: The energy storage charging and discharging power constraints are as follows: （22）； （23）； In the formula: The equivalent charging power for energy storage in the system. For equivalent discharge power, This is the equivalent rated power; The daily charging capacity constraints for energy storage are as follows: （24）； In the formula: δ This indicates the overall charging and discharging efficiency of the energy storage device; The annual charge and discharge capacity constraints for energy storage are as follows: （25）； in, This indicates that the output of new energy sources is hindered; By combining equations (20) and (25), we can obtain the minimum energy storage duration that satisfies the given new energy utilization rate index. : （26）； Step 3.3, solve for the maximum point of the system's energy storage capacity, specifically: Define the maximum energy storage capacity Minimum energy storage capacity and maximum energy storage duration As shown in formula (27), the coordinate points are now determined. This is called the energy storage capacity maxima point. （27）； Obviously, minimum energy storage capacity and the maximum point of energy storage duration Represented as (28) and (29): （28）； （29）。

Images