Energy storage capacity and installation time planning method considering fault rate change

Abstract

The invention discloses an energy storage capacity and installation time planning method considering fault rate change. The method comprises the following steps: 1, dividing an energy storage normal operation state into a healthy state and an aging state; 2, establishing a fault rate function of the energy storage aging stage at the moment t; 3, establishing an energy storage three-state space model considering an aging state; 4, performing equivalence on the energy storage three-state space model to obtain an energy storage fault rate function of the mth period; 5, proposing a main function relationship among the maximum energy storage charging and discharging power, the cycle index, the environment temperature and the failure rate; 6, calculating the energy storage additional capacity and the energy storage installation time in the mth period; and 7, correcting the energy storage installation time by using the sensitivity correction index. According to the method, the influence of the fault rate change of the energy storage aging state on the energy storage capacity is considered, the energy storage capacity of each period is added, and the installation time of each period is corrected, so that the energy storage capacity of the next period is re-planned, and the reliability of a power system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system planning, and specifically relates to a method for planning energy storage capacity and installation time based on energy storage aging stage failure rate identification and power grid reliability sensitivity analysis. Background Art

[0002] With the improvement of the power market and the demand for energy transformation, new energy sources are connected to the power grid on a large scale. Energy storage devices are playing an increasingly important role in balancing the load of the power grid, participating in peak load regulation and frequency regulation, improving the utilization rate of renewable energy, and responding to power grid failures. As an important part of the power system, the capacity configuration and installation time planning of energy storage devices directly affect the reliability of the power system. In order to ensure that the energy storage system can quickly respond to sudden loads and power grid failures and maximize the utilization of energy storage resources, scientific and reasonable capacity configuration and installation time planning should be carried out for energy storage.

[0003] At present, the planning method for the capacity and installation time of energy storage devices often plans the energy storage capacity and its installation time at different time stages based on the load forecast results and the capacity balance relationship. However, this method ignores the impact of the energy storage aging stage, the endurance of the energy storage, and the increase in the energy storage failure rate on the capacity configuration. It only configures the capacity and plans the installation time for the energy storage without considering the change in the failure rate during the aging stage, and cannot add the corresponding capacity in time to meet the reliable operation of the power system. Therefore, in order to meet the reliable operation of the power system, it is of great significance to study the impact of the change in the failure rate of the energy storage aging stage on the energy storage capacity configuration. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned technology and propose a method for planning energy storage capacity and installation time taking into account changes in failure rate, so that on the basis of energy storage capacity and installation time planning, the impact of changes in failure rate of energy storage aging state on energy storage capacity can be considered, the energy storage capacity of each cycle can be added, and the installation time of each cycle can be corrected, so as to realize the re-planning of energy storage capacity for the next cycle, improve the reliability of the power system, and provide strong support for energy storage planning.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme:

[0006] The method for planning energy storage capacity and installation time taking into account changes in failure rate of the present invention is characterized in that it comprises the following steps:

[0007] Step S1: The normal operation state of the energy storage is divided into a healthy state and an aging state, and the change from the healthy state directly to the fault state is recorded as a random fault, and the change from the healthy state to the fault state after the aging state is recorded as an aging fault;

[0008] Step S2: Select Weibull distribution as the failure rate model of energy storage aging stage, and use the recursive least squares method with forgetting factor to identify the parameters of the failure rate model of energy storage aging stage, so as to establish Failure rate function of energy storage aging stage at time ;

[0009] Step S3: Establish a three-state space model of energy storage taking into account the aging state and introduce the random failure ratio , thus obtaining Failure rate function of energy storage from healthy state to fault state at any moment , define the likelihood coefficient , thus obtaining the failure rate function from healthy state to aging state ;

[0010] Step S4: Equivalence the three-state space model of energy storage to a two-state space model, and according to the equal probability of the states before and after the equivalence, the equal frequency of transition to the fault state, and the frequency balance of the aging state, obtain Failure rate function of energy storage at each moment , and discretize it to get Energy storage failure rate function of cycles ;

[0011] Step S5: taking the number of cycles, ambient temperature, and failure rate as influencing factors of energy storage capacity attenuation, respectively establishing sub-function relationship between the maximum charge and discharge power of energy storage and each influencing factor, thereby obtaining a main function relationship between the maximum charge and discharge power and each sub-function relationship;

[0012] Step S6: Calculate the energy storage in the first Maximum power ratio per cycle , thus obtaining The additional capacity of energy storage in a cycle , and calculate the Installation time of energy storage in one cycle ;

[0013] Step S7: Establish the Power grid reliability index considering the aging stage under a cycle , and make the capacity added by energy storage cycle by cycle continuous, thus establishing the first The sensitivity of the grid reliability index to the energy storage failure rate, energy storage additional capacity and time in the aging stage is expressed analytically under the cycle, and the The increment of the grid reliability index taking into account the aging stage in the cycle , get the The corrected time of energy storage in the first cycle is obtained Corrected energy storage installation time under each cycle.

[0014] The method for planning energy storage capacity and installation time taking into account changes in failure rate according to the present invention is also characterized in that step S2 comprises:

[0015] Step S2-1: Take the logarithm of both sides of the failure rate model in the energy storage aging stage, and use formula (1) to construct a fitting polynomial:

[0016] (1)

[0017] In formula (1), for the current moment; for Failure rate function from energy storage aging state to failure state at any moment; , The first constants are and the second constant An estimated value of

[0018] Step S2-2: Use the recursive least squares method with forgetting factor to calculate the two parameters in equation (1): and Perform identification and obtain two estimates and , and substitute it into the failure rate model of the energy storage aging stage, so as to establish The failure rate function from the energy storage aging state to the failure state at the moment, that is, the failure rate function of the energy storage aging stage :

[0019] (2).

[0020] Furthermore, the step S3 includes:

[0021] Step S3-1: Establishing a three-state space model of energy storage taking into account the aging state, including: Failure rate function from the healthy state to the aging state of energy storage at any moment , Failure rate function from energy storage aging state to failure state at time , Failure rate function of energy storage from healthy state to fault state at any moment , the repair rate from fault state to healthy state ;

[0022] Step S3-2: Introducing random failure ratio , and thus use formula (3) to construct Failure rate function of energy storage from healthy state to fault state at any moment :

[0023] (3)

[0024] In formula (3), for The failure rate function of the energy storage from the normal state to the fault state at any moment, that is, the failure rate function of the energy storage;

[0025] Step S3-3: The state transition rate of the energy storage from the healthy state to the aging state and then to the fault state is recorded as , and use formula (4) to construct the constraint conditions:

[0026] (4)

[0027] Step S3-4: Define the likelihood coefficient Indicates the possibility of the energy storage developing from an aging state to a fault state, and , then use formula (5) to construct Failure rate function from the healthy state to the aging state of energy storage at any moment :

[0028] (5).

[0029] Further, the step S4 includes:

[0030] Step S4-1: Equating the energy storage three-state space model taking into account the aging state to a two-state space model, including: Failure rate function from normal state to fault state of energy storage at time , Repair rate from fault state to normal state ;

[0031] Step S4-2: Using formula (6) to obtain Failure rate function from normal state to fault state of energy storage at time :

[0032] (6)

[0033] Step S4-3: Use formula (7) to obtain Failure rate function of energy storage under cycles :

[0034] (7)

[0035] In formula (7), Indicates the total time period of each cycle; Is a positive integer.

[0036] Furthermore, the step S5 comprises:

[0037] Step S5-1: According to the experimental data, the maximum charge and discharge power and the number of energy storage cycles are obtained. The sub-function relationship of ;

[0038] Step S5-2: Measuring the standard temperature of the environment Corresponding maximum charge and discharge power As the reference value, use formula (8) to obtain any ambient temperature The ratio of the maximum charging and discharging power of energy storage to the reference value :

[0039] (8)

[0040] In formula (8), Ambient temperature The corresponding maximum charge and discharge power;

[0041] The sub-function relationship between the maximum charge and discharge power and the ambient temperature is established using formula (9):

[0042] (9)

[0043] In formula (9), is the maximum charge and discharge power; For one cycle Typical temperature sets; is the probability of any typical temperature set appearing in a cycle;

[0044] Step S5-3: Use formula (10) to establish The sub-function relationship between the maximum charge and discharge power of energy storage and the failure rate under a cycle is:

[0045] (10)

[0046] Step S5-4: Use formula (11) to construct Maximum charge and discharge power of energy storage under a cycle The main function relationship with each sub-function is:

[0047] (11)

[0048] In formula (11), , , are 3 fitting coefficients; is the average number of charge and discharge times in one cycle.

[0049] Further, the step S6 includes:

[0050] Step S6-1: Obtain the Maximum charge and discharge power of energy storage under a cycle The maximum charge and discharge power of the energy storage in the first cycle The ratio of Maximum power ratio per cycle ;

[0051] Step S6-2: Calculate the energy storage in the first The comprehensive maximum power ratio under the cycle ;

[0052] (12)

[0053] In formula (12), is a function of the maximum power ratio; For the The additional capacity of energy storage in a cycle, For energy storage The comprehensive maximum power ratio under each cycle;

[0054] Step S6-3: Use formula (13) to obtain The additional capacity of energy storage in a cycle :

[0055] (13)

[0056] In formula (13), is the maximum power ratio of energy storage in the first cycle, and ; The capacity added for the first cycle, i.e. the capacity initially configured for energy storage;

[0057] Step S6-4: Use formula (14) to obtain Installation time of energy storage in one cycle :

[0058] (14)

[0059] In formula (14), It is the installation time of energy storage in the first cycle, that is, the installation time of the initial configuration of energy storage.

[0060] Further, the step S7 includes:

[0061] Step S7-1: Based on fault enumeration and probability weighting algorithm, use formula (15) to construct the first Power grid reliability index considering the aging stage under a cycle :

[0062] (15)

[0063] In formula (15): For the The set of fault moments in a cycle; Indicates In the cycle When the energy storage fails, The probability that the energy storage is operating normally at all times, and ; express Failure rate function of energy storage at each moment; express Load increment at a given moment; is the repair rate from the fault state to the normal state, and ;

[0064] Step S7-2: Use equation (16) and equation (17) to establish The sensitivity of the grid reliability index to the energy storage failure rate and time under the aging stage is expressed analytically:

[0065] (16)

[0066] (17)

[0067] Step S7-3: According to the previous The additional capacity of energy storage in a cycle is constructed using the Lagrange interpolation method. Time interpolation polynomial , in order to achieve the continuous capacity increase of energy storage cycle by cycle;

[0068] Step S7-4: Use equation (18) to establish The sensitivity of the grid reliability index to the energy storage failure rate under the aging stage is expressed analytically as follows:

[0069] (18)

[0070] Step S7-5: Use equation (19) to establish The increment of power grid reliability index considering the aging stage in the cycle :

[0071] (19)

[0072] Step S7-6: Use formula (20) to obtain Correction time of energy storage per cycle :

[0073] (20)

[0074] Step S7-7: Use formula (21) to obtain Corrected energy storage installation time under one cycle :

[0075] (twenty one)

[0076] In formula (21), For the The installation time of energy storage under each cycle.

[0077] An electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the energy storage capacity and installation time planning method, and the processor is configured to execute the program stored in the memory.

[0078] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the energy storage capacity and installation time planning method when the computer program is executed by a processor.

[0079] Compared with the prior art, the present invention has the following beneficial effects:

[0080] 1. The present invention provides a method for planning energy storage capacity and installation time taking into account changes in failure rate. The method can consider the impact of the energy storage device's aging stage, which is the end of its service life and the increase in failure rate, on the energy storage capacity configuration, establish a failure rate model for the energy storage aging stage, and use the recursive least squares method with a forgetting factor to identify the parameters of the failure rate model to obtain the failure rate function for the energy storage aging stage, thus providing a basis for obtaining the failure rate function for energy storage.

[0081] 2. The present invention provides a method for planning energy storage capacity and installation time that takes into account changes in failure rate. When establishing a state space model, the normal operating state of energy storage is divided into a healthy state and an aging state. A three-state space model of energy storage that takes into account the aging state can be established. According to the failure rate function of the aging stage and the equivalent of the state space, the failure rate function of the energy storage is obtained, which provides a basis for reliability analysis of energy storage.

[0082] 3. The present invention provides a method for planning energy storage capacity and installation time that takes into account changes in failure rate. It can propose a power grid reliability index that takes into account the aging stage and derive an analytical expression of the sensitivity of the reliability index to the energy storage failure rate, energy storage additional capacity and time, calculate the increment of the power grid reliability index, and obtain the corrected time of energy storage, thereby correcting the installation time of energy storage and improving the reliability of energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 is a flow chart of the present invention;

[0084] Figure 2 It is a curve diagram of the failure rate change of the energy storage from the stable operation stage to the aging stage of the present invention;

[0085] Figure 3 The energy storage three-state space model diagram and its equivalents taking into account the aging state of the present invention;

[0086] Figure 4 This is the energy storage installation time correction diagram of the present invention. DETAILED DESCRIPTION

[0087] In this embodiment, a method for planning energy storage capacity and installation time that takes into account changes in failure rate is to propose a failure rate model for energy storage aging stage and identify its parameters, to establish a three-state space model of energy storage that takes into account aging status to derive the failure rate function of energy storage, to propose the main function relationship between the maximum charge and discharge power of energy storage and the number of cycles, ambient temperature and failure rate, to calculate the maximum power ratio of energy storage cycle to plan the capacity of energy storage device, to conduct reliability assessment and sensitivity analysis on energy storage device that takes into account aging status, to correct the installation time of energy storage, and to effectively improve the reliability of energy storage capacity configuration. Specifically, if Figure 1 As shown, the method comprises the following steps:

[0088] Step S1: The normal operating state of the energy storage is divided into a healthy state and an aging state, and the change from the healthy state directly to the fault state is recorded as a random fault, which is mainly caused by external factors, such as human error. The change from the healthy state to the fault state after the aging state is recorded as an aging fault, which is mainly caused by internal factors, such as the natural aging of the energy storage with the increase of operating time;

[0089] Step S2: Select Weibull distribution as the failure rate model of the energy storage aging stage, deform the failure rate model, construct a fitting polynomial that satisfies the least squares method, and use the recursive least squares method with forgetting factor to identify the parameters of the failure rate model of the energy storage aging stage, so as to establish Failure rate function of energy storage aging stage at time .

[0090] Step S2-1: The failure rate of energy storage changes from the stable operation stage to the aging stage as follows Figure 2 As shown, the stable operation stage corresponds to the healthy state, and the aging stage corresponds to the aging state. Considering that the failure rate of energy storage in the aging stage increases over time, the Weibull distribution is introduced, and the failure rate model of energy storage in the aging stage is established using formula (1):

[0091] (1)

[0092] In formula (1), for the current moment; for Failure rate function from energy storage aging state to failure state at any moment; is the first constant; is the second constant, and At this time, the failure rate has an upward characteristic, which meets the changing characteristics of the energy storage failure rate in the aging stage.

[0093] Step S2-2: Take the logarithm of both sides of the failure rate model in the energy storage aging stage, and use formula (2) to construct a fitting polynomial:

[0094] (2)

[0095] In formula (2), , The first constants are and the second constant The estimated value of .

[0096] Step S2-3: Write equation (2) into vector form:

[0097] (3)

[0098] In formula (3), is the output vector; is the information vector; is the parameter vector to be identified.

[0099] Step S2-4: Define the indicator function is the sum of the distances from each point to the fitting polynomial. In order to weaken the impact of data saturation, the forgetting factor is introduced , in order to reduce the effect of old data, the error sum of squares is constructed using formula (4) :

[0100] (4)

[0101] Step S2-5: The least square method requires the minimum sum of squared errors, and minimizes formula (4), so as to obtain the recursive least square identification formula with forgetting factor using formula (5):

[0102] (5)

[0103] In formula (5), is the parameter estimate; is the gain vector; is the identity matrix; is the covariance matrix; is the forgetting factor, which is usually between 0.95 and 1.

[0104] Step S2-6: Setting initial values , and let ,in is a sufficiently small positive real vector or a zero vector, is a sufficiently large positive real number, is the identity matrix;

[0105] Step S2-7: By continuously obtaining new energy storage failure rates, substituting the newly obtained data into formula (5) for iteration, and continuously correcting the original estimation results, the parameter and , and use formula (6) to get the estimated value and :

[0106] (6)

[0107] Step S2-8: Put the two estimated values and Substitute into the failure rate model, and then use formula (7) to establish The failure rate function from the energy storage aging state to the failure state at the moment, that is, the failure rate function of the energy storage aging stage :

[0108] (7)

[0109] Step S3: Establish a three-state space model of energy storage taking into account the aging state and introduce the random failure ratio , thus obtaining Failure rate function of energy storage from healthy state to fault state at any moment , define the likelihood coefficient , thus obtaining the failure rate function from healthy state to aging state .

[0110] Step S3-1: Establish a three-state space model of energy storage taking into account the aging state, such as Figure 3 As shown, including: HC, AC, FC are the health state, aging state and fault state of energy storage respectively; Failure rate function from the healthy state to the aging state of energy storage at any moment ; Failure rate function from energy storage aging state to failure state at time ; Failure rate function of energy storage from healthy state to fault state at any moment ; Repair rate from fault state to healthy state ;

[0111] Step S3-2: Introducing random failure ratio , and thus use formula (8) to construct Failure rate function of energy storage from healthy state to fault state at any moment :

[0112] (8)

[0113] In formula (8), for The failure rate function of the energy storage from the normal state to the fault state at any moment, that is, the failure rate function of the energy storage;

[0114] Step S3-3: The state transition rate of the energy storage from the healthy state to the aging state and then to the fault state is recorded as Considering that the aging state may not develop into a fault, the constraint condition is constructed using formula (9):

[0115] (9)

[0116] Step S3-4: Define the likelihood coefficient Indicates the possibility of the energy storage developing from an aging state to a fault state, and , then use formula (10) to construct Failure rate function from the healthy state to the aging state of energy storage at any moment :

[0117] (10)

[0118] Step S4: Equivalence the three-state space model of energy storage to a two-state space model, and obtain the following according to the equal probability of the states before and after the equivalence, the equal frequency of transition to the fault state, and the frequency balance of the aging state: Failure rate function of energy storage at each moment , and discretize it to get Energy storage failure rate function of cycles .

[0119] Step S4-1: Equivalently convert the energy storage three-state space model taking into account the aging state into a two-state space model, such as Figure 3 As shown, including: UP and FC are the normal state and fault state of energy storage respectively; Failure rate function from normal state to fault state of energy storage at time , the repair rate from fault state to normal state ;

[0120] Step S4-2: The state probabilities before and after the equal value are equal, the frequencies of transition to the fault state before and after the equal value are equal, and the aging state frequency is balanced, as shown in equations (11), (12), and (13):

[0121] (11)

[0122] (12)

[0123] (13)

[0124] In formula (11), , are the state probabilities of energy storage healthy state and energy storage aging state respectively; is the state probability of the energy storage in normal operation, through the state transition rate matrix of the energy storage , using formula (14) to obtain the state probability of energy storage in normal operation:

[0125] (14)

[0126] Step S4-3: Combine equation (11), equation (12), and equation (13) and convert , , Substituting into equation (11), equation (12), and equation (13), we can obtain equation (15) Failure rate function from normal state to fault state of energy storage at time :

[0127] (15)

[0128] Step S4-4: Set the energy storage failure rate In the time interval Integrate and average the values, and use formula (16) to get Failure rate function of energy storage per cycle :

[0129] (16)

[0130] In formula (16), Indicates the total time period of each cycle; is a positive integer;

[0131] Step S5: Taking the number of cycles, ambient temperature, and failure rate as influencing factors of energy storage capacity attenuation, sub-function relationship equations between the maximum charge and discharge power of energy storage and each influencing factor are established respectively, so as to obtain the main function relationship equation between the maximum charge and discharge power and each sub-function relationship.

[0132] Step S5-1: Each charge and discharge process of the energy storage will reduce its maximum charge and discharge power. According to the experimental data, the maximum charge and discharge power and the number of energy storage cycles are obtained using formula (17). The sub-function relationship of is:

[0133] (17)

[0134] In the formula, is the maximum charge and discharge power; , , are three fitting coefficients, which can be obtained based on the charging and discharging power distribution data of the same type of energy storage at the provided external temperature and the probability of temperature occurrence in one cycle.

[0135] Step S5-2: Measuring the standard temperature of the environment Corresponding maximum charge and discharge power As the reference value, use formula (18) to obtain any ambient temperature The ratio of the maximum charging and discharging power of energy storage to the reference value :

[0136] (18)

[0137] In formula (18), Ambient temperature The corresponding maximum charge and discharge power.

[0138] The sub-function relationship between the maximum charge and discharge power and the ambient temperature is established using formula (19):

[0139] (19)

[0140] In formula (19), For one cycle Typical temperature sets; is the probability of any typical temperature set appearing in a cycle.

[0141] Step S5-3: Use formula (20) to establish The sub-function relationship between the maximum charge and discharge power of energy storage and the failure rate under a cycle is:

[0142] (20)

[0143] Step S5-4: Use formula (21) to construct Maximum charge and discharge power of energy storage under a cycle The main function relationship with each sub-function is:

[0144] (twenty one)

[0145] In formula (21), is the average number of charge and discharge times in one cycle.

[0146] Step S6: Calculate the energy storage in the first Maximum power ratio per cycle , thus obtaining The additional capacity of energy storage in a cycle , and calculate the Installation time of energy storage in one cycle .

[0147] Step S6-1: Obtain the Maximum charge and discharge power of energy storage under a cycle The maximum charge and discharge power of the energy storage in the first cycle The ratio of the energy storage in the first Maximum power ratio per cycle :

[0148] (twenty two)

[0149] Step S6-2: Use equation (23) to construct the relationship between the energy storage capacity decay and the energy storage capacity addition in each cycle:

[0150] (twenty three)

[0151] In formula (23), is the maximum power ratio of energy storage in the first cycle, ; is a positive integer, and ; The capacity added for the first cycle, i.e. the capacity initially configured for energy storage; For the The additional capacity of energy storage in each cycle.

[0152] Step S6-3: Write formula (24) according to formula (23). For the convenience of expression, introduce the first The comprehensive maximum power ratio of each cycle :

[0153] (twenty four)

[0154] Step S6-4: Derivation of energy storage in the first The comprehensive maximum power ratio under the cycle ;

[0155] (25)

[0156] In formula (25), is a function of the maximum power ratio, For the The additional capacity of energy storage in a cycle, For energy storage The comprehensive maximum power ratio under each cycle.

[0157] Step S6-5: Combine equation (24) and equation (25) to obtain The additional capacity of energy storage in a cycle :

[0158] (26)

[0159] Step S6-6: Use formula (27) to obtain Installation time of energy storage in one cycle :

[0160] (27)

[0161] In formula (27), It is the installation time of energy storage in the first cycle, that is, the installation time of the initial configuration of energy storage.

[0162] Step S7: Establish the Power grid reliability index considering the aging stage under a cycle , the capacity of energy storage added period by period is continuous, thus establishing the The sensitivity of the grid reliability index to the energy storage failure rate, energy storage additional capacity and time in the aging stage is expressed analytically under the cycle, and the The increment of the grid reliability index taking into account the aging stage in the cycle , get the The corrected time of energy storage in the first cycle is obtained Corrected energy storage installation time under each cycle.

[0163] Step S7-1: Based on fault enumeration and probability weighting algorithm, use formula (15) to construct the first Power grid reliability index considering the aging stage under a cycle :

[0164] (28)

[0165] In formula (28): For the The set of fault moments in a cycle; Indicates In the cycle When the energy storage fails, The probability that the energy storage is operating normally at all times, and ; express Failure rate function of energy storage at each moment; express Load increment at a given moment; is the repair rate from fault state to normal state, ;

[0166] Step S7-2: Use equation (29) and equation (30) to establish The sensitivity of the grid reliability index to the energy storage failure rate and time under the aging stage is expressed analytically:

[0167] (29)

[0168] (30)

[0169] Step S7-3: According to the previous The additional capacity of energy storage in a cycle is constructed using the Lagrange interpolation method. Time interpolation polynomial , in order to achieve the continuous capacity increase of energy storage cycle by cycle;

[0170] (31)

[0171] Step S7-4: Use equation (32) to establish The sensitivity of the grid reliability index to the energy storage failure rate under the aging stage is expressed analytically as follows:

[0172] (32)

[0173] Step S7-5: Use equation (33) to establish The increment of power grid reliability index considering the aging stage in the cycle :

[0174] (33)

[0175] Step S7-6: Use equation (34) to obtain Correction time of energy storage per cycle :

[0176] (34)

[0177] Step S7-7: Use equation (35) to obtain Corrected energy storage installation time under one cycle ,like Figure 4 As shown, the capacity allocated for energy storage; For the The capacity required for energy storage in a cycle. If no additional capacity is required in this cycle, then ; For the The installation time of energy storage before correction in each cycle; For the Corrected energy storage installation time under a cycle:

[0178] (35)

[0179] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0180] In this embodiment, a computer-readable storage medium stores a computer program on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

Claims

1. A method for planning energy storage capacity and installation time taking into account changes in failure rate, characterized in that: The following steps are involved: Step S1: The normal operation state of the energy storage is divided into a healthy state and an aging state, and the change from the healthy state directly to the fault state is recorded as a random fault, and the change from the healthy state to the fault state after the aging state is recorded as an aging fault; Step S2: Select Weibull distribution as the failure rate model of energy storage aging stage, and use the recursive least squares method with forgetting factor to identify the parameters of the failure rate model of energy storage aging stage, so as to establish Failure rate function of energy storage aging stage at time ; Step S3: Establish a three-state space model of energy storage taking into account the aging state and introduce the random failure ratio , thus obtaining Failure rate function of energy storage from healthy state to fault state at any moment , define the likelihood coefficient , thus obtaining the failure rate function from healthy state to aging state ; Step S4: Equivalence the three-state space model of energy storage to a two-state space model, and according to the equal probability of the states before and after the equivalence, the equal frequency of transition to the fault state, and the frequency balance of the aging state, obtain Failure rate function of energy storage at each moment , and discretize it to get Energy storage failure rate function of cycles ; Step S5: taking the number of cycles, ambient temperature, and failure rate as influencing factors of energy storage capacity attenuation, respectively establishing sub-function relationship between the maximum charge and discharge power of energy storage and each influencing factor, thereby obtaining a main function relationship between the maximum charge and discharge power and each sub-function relationship; Step S6: Calculate the energy storage in the first Maximum power ratio per cycle , thus obtaining The additional capacity of energy storage in a cycle , and calculate the Installation time of energy storage in one cycle ; Step S7: Establish the Power grid reliability index considering the aging stage under a cycle , and make the capacity added by energy storage cycle by cycle continuous, thus establishing the first The sensitivity of the grid reliability index to the energy storage failure rate, energy storage additional capacity and time in the aging stage is expressed analytically under the cycle, and the The increment of the grid reliability index taking into account the aging stage in the cycle , get the The corrected time of energy storage in the first cycle is obtained Corrected energy storage installation time under each cycle.

2. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 1, characterized in that: The step S2 comprises: Step S2-1: Take the logarithm of both sides of the failure rate model in the energy storage aging stage, and use formula (1) to construct a fitting polynomial: (1) In formula (1), for the current moment; for Failure rate function from energy storage aging state to failure state at any moment; , The first constants are and the second constant An estimated value of Step S2-2: Use the recursive least squares method with forgetting factor to calculate the two parameters in equation (1): and Perform identification and obtain two estimates and , and substitute it into the failure rate model of the energy storage aging stage, so as to establish The failure rate function from the energy storage aging state to the failure state at the moment, that is, the failure rate function of the energy storage aging stage : (2)。 3. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 2, characterized in that: The step S3 comprises: Step S3-1: Establishing a three-state space model of energy storage taking into account the aging state, including: Failure rate function from the healthy state to the aging state of energy storage at any moment , Failure rate function from energy storage aging state to failure state at time , Failure rate function of energy storage from healthy state to fault state at any moment , the repair rate from fault state to healthy state ; Step S3-2: Introducing random failure ratio , and thus use formula (3) to construct Failure rate function of energy storage from healthy state to fault state at any moment : (3) In formula (3), for The failure rate function of the energy storage from the normal state to the fault state at any moment, that is, the failure rate function of the energy storage; Step S3-3: The state transition rate of the energy storage from the healthy state to the aging state and then to the fault state is recorded as , and use formula (4) to construct the constraint conditions: (4) Step S3-4: Define the likelihood coefficient Indicates the possibility of the energy storage developing from an aging state to a fault state, and , then use formula (5) to construct Failure rate function from the healthy state to the aging state of energy storage at any moment : (5)。 4. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 3, characterized in that: The step S4 comprises: Step S4-1: Equating the energy storage three-state space model taking into account the aging state to a two-state space model, including: Failure rate function from normal state to fault state of energy storage at time , Repair rate from fault state to normal state ; Step S4-2: Using formula (6) to obtain Failure rate function from normal state to fault state of energy storage at time : (6) Step S4-3: Use formula (7) to obtain Failure rate function of energy storage under cycles : (7) In formula (7), Indicates the total time period of each cycle; Is a positive integer.

5. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 4, characterized in that: The step S5 comprises: Step S5-1: According to the experimental data, the maximum charge and discharge power and the number of energy storage cycles are obtained. The sub-function relationship of ; Step S5-2: Measuring the standard temperature of the environment Corresponding maximum charge and discharge power As the reference value, use formula (8) to obtain any ambient temperature The ratio of the maximum charging and discharging power of energy storage to the reference value : (8) In formula (8), Ambient temperature The corresponding maximum charge and discharge power; The sub-function relationship between the maximum charge and discharge power and the ambient temperature is established using formula (9): (9) In formula (9), is the maximum charge and discharge power; For one cycle Typical temperature sets; is the probability of any typical temperature set appearing in a cycle; Step S5-3: Use formula (10) to establish The sub-function relationship between the maximum charge and discharge power of energy storage and the failure rate in a cycle is: (10) Step S5-4: Use formula (11) to construct Maximum charge and discharge power of energy storage under a cycle The main function relationship with each sub-function is: (11) In formula (11), , , are 3 fitting coefficients; is the average number of charge and discharge times in one cycle.

6. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 5, characterized in that: The step S6 comprises: Step S6-1: Obtain the Maximum charge and discharge power of energy storage under a cycle The maximum charge and discharge power of the energy storage in the first cycle The ratio of Maximum power ratio per cycle ; Step S6-2: Calculate the energy storage in the first The comprehensive maximum power ratio under the cycle ; (12) In formula (12), is a function of the maximum power ratio; For the The additional capacity of energy storage in a cycle, For energy storage The comprehensive maximum power ratio under each cycle; Step S6-3: Use formula (13) to obtain The additional capacity of energy storage in a cycle : (13) In formula (13), is the maximum power ratio of energy storage in the first cycle, and ; The capacity added for the first cycle, i.e. the capacity initially configured for energy storage; Step S6-4: Use formula (14) to obtain Installation time of energy storage in one cycle : (14) In formula (14), It is the installation time of energy storage in the first cycle, that is, the installation time of the initial configuration of energy storage.

7. A method for planning energy storage capacity and installation time taking into account changes in failure rate according to claim 6, characterized in that: The step S7 comprises: Step S7-1: Based on fault enumeration and probability weighting algorithm, use formula (15) to construct the first Power grid reliability index considering the aging stage under a cycle : (15) In formula (15): For the The set of fault moments in a cycle; Indicates In the cycle When the energy storage fails, The probability that the energy storage is operating normally at all times, and ; express Failure rate function of energy storage at each moment; express Load increment at a given moment; is the repair rate from the fault state to the normal state, and ; Step S7-2: Use equation (16) and equation (17) to establish The sensitivity of the grid reliability index to the energy storage failure rate and time under the aging stage is expressed analytically: (16) (17) Step S7-3: According to the previous The additional capacity of energy storage in a cycle is constructed using the Lagrange interpolation method. Time interpolation polynomial , in order to achieve the continuous capacity increase of energy storage cycle by cycle; Step S7-4: Use equation (18) to establish The sensitivity of the grid reliability index to the energy storage failure rate under the aging stage is expressed analytically as follows: (18) Step S7-5: Use equation (19) to establish The increment of power grid reliability index considering the aging stage in the cycle : (19) Step S7-6: Use formula (20) to obtain Correction time of energy storage per cycle : (20) Step S7-7: Use formula (21) to obtain Corrected energy storage installation time under one cycle : (21) In formula (21), For the The installation time of energy storage under each cycle.

8. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the energy storage capacity and installation time planning method described in any one of claims 1-7, and the processor is configured to execute the program stored in the memory.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the energy storage capacity and installation time planning method described in any one of claims 1 to 7 are executed.

Images