An optimization method for the spinning reserve rate of a wind power integrated power system

Abstract

The present invention provides a method for optimizing the spinning reserve rate of a power system containing wind power, which includes the following steps: calculating the outage loss according to the reliability of each power generation system in the power system; calculating the power generation investment operation cost and the wind power abandonment cost of the power system according to the spinning reserve rate and the peak shaving capacity of the power system; comparing the increase value of the power generation investment operation cost and the wind power abandonment cost with the decrease value of the outage loss; if there is a deviation between the increase value and the decrease value, adjusting the spinning reserve rate of the power system; until there is no deviation between the increase value and the decrease value, determining the current spinning reserve rate of the power system as the optimal spinning reserve rate. The present invention can comprehensively and overall consider the comprehensive cost of power system reliability, valley peak shaving capacity, investment economic cost required for reserve and the cost of wind abandonment, can obtain the optimal spinning reserve rate of the power system containing wind power, thereby can reduce the comprehensive power generation cost of the power system and improve the operation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and particularly to an optimization method for the spinning reserve rate of a power system containing wind power. Background Art

[0002] In a power system, in order to ensure stable and reliable power supply, a certain reserve capacity is usually reserved to prevent random failures of generating units and transmission structures or unexpected fluctuations in load. The large-scale grid connection of wind power has a great impact on the selection of the spinning reserve rate of the power system. The main aspects include the following two points: 1) The required reserve capacity increases. Due to the influence of natural factors, wind power has large intermittency and random volatility. Therefore, when the proportion of wind power in the power grid increases, in order to ensure sufficient power supply at the maximum load, the spinning reserve capacity needs to increase with the increase of the wind power capacity. 2) It is difficult to adjust the power peak of the power grid. Wind power has the characteristic of reverse peak regulation, that is, the output rate is relatively low during peak power consumption periods and relatively high during low power consumption periods. And some of the spinning reserve capacity is thermal power units that are only switched on and off once within a day. As the spinning reserve capacity increases due to the increase of the wind power capacity, the output of thermal power during low valleys also increases. This makes it more likely to have difficulties in insufficient peak regulation capacity when wind power generates a large amount during low load valleys. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides an optimization method for the spinning reserve rate of a power system containing wind power, which can comprehensively consider the comprehensive cost of power system reliability, low valley peak regulation capacity, investment economic cost required for reserve, and curtailment cost of wind power, and can obtain the optimal spinning reserve rate of the power system containing wind power, thereby reducing the comprehensive power generation cost of the power system and improving the operation efficiency.

[0004] The technical solution adopted by the present invention is as follows:

[0005] An optimization method for the spinning reserve rate of a power system containing wind power, comprising the following steps: calculating the power outage loss according to the reliability of each power generation system in the power system; calculating the power generation investment operation cost and the curtailment cost of wind power of the power system according to the spinning reserve rate and peak regulation capacity of the power system; comparing the increase value of the power generation investment operation cost and the curtailment cost of wind power with the decrease value of the power outage loss; if there is a deviation between the increase value and the decrease value, adjusting the spinning reserve rate of the power system; until there is no deviation between the increase value and the decrease value, determining the current spinning reserve rate of the power system as the optimal spinning reserve rate.

[0006] Calculate the power outage loss according to the following formula:

[0007] F a = CFL·EENS

[0008] Wherein, Fa For the power outage loss, CFL is the cost of power outage loss per unit of electricity, and EENS is the reduction in electricity consumption by users due to system unreliability, where

[0009]

[0010] where T is the research period, P(F i ) is the occurrence probability of the failure state F of the power generation system i i and DNS(F i ) represents the power shortage caused by the lack of sufficient capacity of the power generation equipment to meet all load demands when the power generation system i is in the failure state F i .

[0011] The power generation investment and operation cost is calculated according to the following formula:

[0012]

[0013] where F b is the power generation investment and operation cost, P i is the installed capacity of the i-th unit in the power system, K i is the annual cost per kilowatt of installed capacity of the i-th unit, β i is the annual fixed operation rate of the i-th unit, n is the investment payback period, N is the number of units in the power system that are in the on state, M is the number of units in the power system that are in the off state, and r is the discount rate.

[0014] The curtailment cost of wind power is calculated according to the following formula:

[0015]

[0016] where F c is the curtailment cost of wind power, and β0 is the on-grid electricity price, where

[0017]

[0018] where AP OW (x) is defined as the curtailed wind power that meets the peak shaving capacity constraint at the x-th time period under a specific spinning reserve rate, and AE OW is the corresponding curtailed wind power volume.

[0019] If there is a deviation between the increased value and the decreased value, then adjust the spinning reserve rate of the power system, specifically including: if the increased value is greater than the decreased value, then decrease the spinning reserve rate of the power system; if the increased value is less than or equal to the decreased value, then increase the spinning reserve rate of the power system.

[0020] Wherein, if the absolute value of the difference between the increased value and the decreased value is greater than a preset threshold, it is determined that there is a deviation between the increased value and the decreased value.

[0021] Advantages of the present invention:

[0022] The present invention first calculates the power outage loss according to the reliability of each power generation system in the power system, and calculates the power generation investment operation cost and the wind power abandonment cost of the power system according to the spinning reserve rate and the peak shaving capacity of the power system. Then, it compares the increased value of the power generation investment operation cost and the wind power abandonment cost with the decreased value of the power outage loss. If there is a deviation between the increased value and the decreased value, it adjusts the spinning reserve rate of the power system until there is no deviation between the increased value and the decreased value, and determines the current spinning reserve rate of the power system as the optimal spinning reserve rate. Thus, comprehensively considering the comprehensive cost of power system reliability, valley peak shaving capacity, investment economic cost required for reserve and wind abandonment cost, the optimal spinning reserve rate of the power system with wind power can be obtained, thereby reducing the comprehensive power generation cost of the power system and improving the operation efficiency. Description of the drawings

[0023] Figure 1 is a flowchart of the method for optimizing the spinning reserve rate of a wind power-integrated power system according to an embodiment of the present invention;

[0024] Figure 2 is a flowchart of the method for optimizing the spinning reserve rate of a wind power-integrated power system according to a specific embodiment of the present invention. Detailed implementation manners

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] The method for optimizing the spinning reserve rate of a wind power-integrated power system according to an embodiment of the present invention aims to optimize the spinning reserve rate of the power system, that is, the ratio of the spinning reserve capacity to the total capacity, to obtain the optimal spinning reserve rate.

[0027] As Figure 1 shown, the method for optimizing the spinning reserve rate of a wind power-integrated power system according to an embodiment of the present invention includes the following steps:

[0028] S1, calculating the power outage loss according to the reliability of each power generation system in the power system.

[0029] The power system in the embodiment of the present invention includes one or more wind power systems and one or more other power generation systems, and the other power generation systems may include thermal power systems, hydropower systems, etc. Each power generation system in the embodiment of the present invention corresponds to a generating set.

[0030] The requirements for the power generation reliability level of the power system have a direct impact on the economy and reliability of the power system. A high reliability standard can improve the ability of the power system to cope with uncertainties such as accidents, but it will lead to an increase in the investment and operation costs of the power generation system; a low reliability standard can reduce the investment and operation costs of the power generation system, but it will increase the risk of damaging the national economy and have an adverse impact on social life. In order to reasonably balance the relationship between the two and maximize the comprehensive benefits of the power generation system, input-output analysis should be carried out. The improvement of the spinning reserve capacity helps to improve the power generation reliability level of the system, and thus the social benefits brought about by the improvement of the reliability level. Since social benefits are difficult to measure quantitatively, generally, the reduction of power outage loss is mainly used to measure the output.

[0031] The expected demand not served (EDNS) represents the expected value of the power lost due to power supply shortage caused by forced outages of generating units in the power system, and can be expressed by the following formula:

[0032]

[0033] where P(F i ) is the probability of the occurrence of the failure state F i of the generating system i, and DNS(F i ) represents the power shortage caused by the lack of sufficient capacity of the generating equipment to meet all load demands in the generating system i in the failure state F i .

[0034] Multiplying the expected demand not served by the duration of a certain research period can obtain the expected energy not served (EENS) during this research period, which can be expressed by the following formula:

[0035]

[0036] where T is the research period, generally taking 8760 hours for the whole year.

[0037] EENS is the reduction in the electricity consumption of users due to the unreliability of the system, so the power outage loss can be calculated based on this. Calculating this indicator requires considering the hourly load changes, and generally, the load duration curve (LDC) is used as the load model.

[0038] The power outage loss F a can be expressed as:

[0039] Fa = CFL·EENS

[0040] Among them, CFL is the electricity quantity per unit, for example, the cost of power outage loss per kilowatt-hour. The magnitude of this value is S times the local power generation ratio. The selection of the S value is related to the local gross domestic product and is generally below 7.

[0041] S2, calculate the power generation investment operation cost and the wind power curtailment cost of the power system according to the spinning reserve rate and peak shaving capacity of the power system.

[0042] Different system spinning reserve rates correspond to different system power generation investment operation costs. At the same time, the starting mode corresponding to the system spinning reserve rate also restricts the peak shaving capacity of the system. Due to the reverse peak shaving characteristics of wind power and the invariance of part of the spinning reserve capacity within a day, when the growth of wind power scale and the increase of spinning reserve rate lead to the over-limit period of the above constraints, it is necessary to reduce the grid-connected scale of wind power during this period to ensure the safe and stable operation of the power system, that is, curtail wind power to ensure that the peak shaving capacity meets the requirements.

[0043] The power generation investment operation cost of the power system includes investment cost and fixed operation cost. The power generation investment operation cost F b The calculation formula is as follows:

[0044]

[0045] Among them, P i is the installed capacity of the i-th unit in the power system, K i is the annual cost per kilowatt of installed capacity of the i-th unit, β i is the annual fixed operation rate of the i-th unit, n is the investment payback period, N is the number of units in the power system in the on-state, M is the number of units in the power system in the off-state, r is....

[0046] The wind power curtailment quantity AE OW can be considered as the integral of the wind power generation power that needs to be reduced to meet the peak shaving capacity constraint in each time period. Define AP OW (x) as the wind power curtailment power that meets the peak shaving capacity constraint in the x-th time period under a specific spinning reserve rate. The corresponding wind power curtailment quantity AE OW is:

[0047]

[0048] Among them, each time period takes 1 hour, and T takes 8760.

[0049] The annual wind power curtailment cost can be further calculated according to the on-grid electricity price β0 and converted into an equivalent investment loss through the annual value / present value conversion factor, denoted as the wind power curtailment cost F c :

[0050]

[0051] S3. Compare the increase in the power generation investment operation cost and the wind power curtailment cost with the decrease in the power outage loss.

[0052] For a power system with wind power, when determining the most appropriate spinning reserve capacity under the condition of meeting the basic power and electricity balance, the comprehensive power generation cost F of the system should be minimized. NB The comprehensive power generation cost F is defined as the sum of the power generation investment operation cost, the wind power curtailment cost, and the power outage loss of the power system, that is

[0053]

[0054] Let P Σ be the sum of the on - line capacities of all units in the system. It is certain that a coefficient ρ can be found such that:

[0055]

[0056] Then the calculation formula of the comprehensive power generation cost F NB can be simplified to:

[0057] F NB = CFL·EENS + ρ·P Σ + C·AE OW

[0058] In this formula, the first term is the power outage loss, which is related to the on - line mode of the system; the second term is the power generation investment operation cost, including the annual cost of the system installed capacity investment and the annual fixed operation cost, which is related to the system installed capacity scale and the on - line mode; the third term is the wind power curtailment cost, which is related to the system peak - shaving ability. At the same time, it is assumed that the required installed capacity scale of the system is equal to the on - line capacity plus the shutdown reserve capacity, that is, it is assumed that there are no idle units, and no maintenance is arranged under the peak mode.

[0059] To find the extreme value of F NB and the corresponding optimal installed capacity reserve ratio, take the partial derivative of the above formula and set the partial derivative value equal to 0, we have:

[0060]

[0061] Replace the partial derivative with the difference, then the above formula can be modified to:

[0062]

[0063] The condition for the optimal installed capacity is thus obtained as:

[0064] CFL·ΔEENS + C·ΔAE OW = ΔP Σ ·ρ

[0065] Wherein, CFL·ΔEENS is the reduced value of power outage loss, and C·ΔAE OW is the increased value of the cost of wind power curtailment, and ρ·ΔP Σ is the increased value of the power generation investment operation cost. The increased value and reduced value in the embodiments of the present invention can be the change situation of a research period relative to the previous research period. It can be seen from this formula that when starting to increase the spinning reserve rate under the condition of insufficient system on-line capacity, the increased power generation investment operation cost and the cost of wind power curtailment are less than the power outage loss, that is, CFL·ΔEENS + C·ΔAE OW < ρ·ΔP Σ , and at this time, increasing the spinning reserve rate is beneficial. When the two are equal, it is not cost-effective to continue to increase. Similarly, when starting to reduce the on-line capacity under the condition of too high system spinning reserve rate, the reduced value of the power generation investment operation cost and the cost of wind power curtailment is greater than the increased value of the power outage loss, and at this time, reducing the on-line capacity is reasonable. When the reduced value of the power generation investment operation cost and the cost of wind power curtailment is equal to the increased value of the power outage loss, it is not cost-effective to continue to reduce the on-line capacity.

[0066] Therefore, the system that satisfies the equality of the increased value of the operation and curtailment cost and the reduced value of the power outage loss should be the system with the lowest comprehensive power generation cost and the most reasonable reliability. Its corresponding on-line capacity corresponds to the optimal reserve rate of the system, and its corresponding expected power shortage time is the optimal reliability index of the system.

[0067] S4. If there is a deviation between the increased value and the reduced value, adjust the spinning reserve rate of the power system.

[0068] According to the above conclusion, if the increased value is greater than the reduced value, reduce the spinning reserve rate of the power system; if the increased value is less than or equal to the reduced value, increase the spinning reserve rate of the power system.

[0069] In an embodiment of the present invention, if the absolute value of the difference between the increased value and the reduced value is greater than a preset threshold, it is determined that there is a deviation between the increased value and the reduced value. Or, if the percentage difference between the increased value and the reduced value is greater than a preset percentage, it is determined that there is a deviation between the increased value and the reduced value.

[0070] After adjusting the spinning reserve rate of the power system, return to steps S1 to S3, and execute the above cost calculation and comparison process again.

[0071] S5. Until there is no deviation between the increased value and the reduced value, determine the current spinning reserve rate of the power system as the optimal spinning reserve rate.

[0072] In a specific embodiment of the present invention, as Figure 2 shown, the method for optimizing the spinning reserve rate of a power system with wind power includes the following steps:

[0073] S201, Calculate initialization and parameter setting. In this step, each parameter can be initialized and set, such as the research period, the failure rate of the power generation system, the installed capacity of the unit, and the annual cost, etc.

[0074] S202, Conduct the calculation of power outage losses.

[0075] S203, Conduct the calculation of power generation investment and operation costs.

[0076] S204, Combine the peak shaving capacity constraint to calculate the curtailment cost of wind power.

[0077] S205, Determine whether the absolute value of the difference between the increase value of the power generation investment and operation costs and the curtailment cost of wind power and the decrease value of the power outage losses is greater than the preset threshold. If so, execute step S206; if not, execute step S209.

[0078] S206, Determine whether the increase value of the power generation investment and operation costs and the curtailment cost of wind power is greater than the decrease value of the power outage losses. If so, execute step S207; if not, execute step S208.

[0079] S207, Reduce the spinning reserve rate. After this step, return to step S202.

[0080] S208, Increase the spinning reserve rate. After this step, return to step S202.

[0081] S209, Determine the value of the total spinning reserve rate in the planned horizon year.

[0082] According to the method for optimizing the spinning reserve rate of a wind power - integrated power system according to an embodiment of the present invention, first calculate the power outage losses according to the reliability of each power generation system in the power system, and calculate the power generation investment and operation costs and the curtailment cost of wind power of the power system according to the spinning reserve rate and peak shaving capacity of the power system. Then compare the increase value of the power generation investment and operation costs and the curtailment cost of wind power with the decrease value of the power outage losses. If there is a deviation between the increase value and the decrease value, adjust the spinning reserve rate of the power system until there is no deviation between the increase value and the decrease value, and determine the current spinning reserve rate of the power system as the optimal spinning reserve rate. Thus, comprehensively considering the comprehensive cost of the power system reliability, valley peak shaving capacity, investment economic cost required for reserve, and curtailment cost of wind power, the optimal spinning reserve rate of the wind power - integrated power system can be obtained, thereby reducing the comprehensive power generation cost of the power system and improving the operation efficiency.

[0083] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more unless specifically defined otherwise.

[0084] In the present invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0086] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0087] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0088] Logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with such instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, as the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0089] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following techniques known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0090] Those of ordinary skill in the art can understand that all or part of the steps carried out in implementing the above-described embodiment methods can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0091] In addition, in each of the embodiments of the present invention, the functional units can be integrated in a processing module, or each unit can exist physically alone, or two or more units can be integrated in a module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0092] The storage medium mentioned above can be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for optimizing the spinning reserve rate of a wind power integrated power system, characterized in that It includes the following steps: Calculate the outage loss according to the reliability of each power generation system in the power system; Calculate the power generation investment operation cost and the wind power curtailment cost of the power system according to the spinning reserve rate and peak shaving capacity of the power system. Curtailing wind power means reducing the grid-connected scale of wind power to ensure the safe and stable operation of the power system; Compare the increase value of the power generation investment operation cost and the wind power curtailment cost with the decrease value of the outage loss; If there is a deviation between the increase value and the decrease value, adjust the spinning reserve rate of the power system; Until there is no deviation between the increase value and the decrease value, determine the current spinning reserve rate of the power system as the optimal spinning reserve rate; Calculate the outage loss according to the following formula: F a = CFL·EENS Among them, F a is the power outage loss, CFL is the cost of power outage loss per unit of electricity, and EENS is the reduction in electricity consumption by users due to system unreliability. Among them, Among them, T is the research period, P(F i ) is the occurrence probability of the fault state F of the power generation system i i , and DNS(F i ) represents the power shortage caused by the fact that the power generation equipment of the power generation system i does not have sufficient capacity to meet all load demands in the fault state F i ​ Calculate the power generation investment operation cost according to the following formula: Among them, F b is the power generation investment operation cost, P i is the installed capacity of the i-th unit in the power system, K i is the annual cost per kilowatt installed capacity of the i-th unit, β i is the annual fixed operation rate of the i-th unit, n is the investment payback period, N is the number of units in the power system that are in the on state, M is the number of units in the power system that are in the off state, and r is the discount rate. Calculate the wind power curtailment cost according to the following formula: Among them, F c is the curtailment cost of wind power, and β0 is the on-grid electricity price, where Among them, AP OW (x) is defined as the wind power curtailment power that meets the peak shaving capacity constraint in the x-th period under a specific spinning reserve rate, and AE OW is the corresponding wind power curtailment amount.

2. The method for optimizing the spinning reserve rate of a wind power integrated power system according to claim 1, wherein, If there is a deviation between the increase value and the decrease value, adjust the spinning reserve rate of the power system, specifically including: If the increase value is greater than the decrease value, reduce the spinning reserve rate of the power system; If the increase value is less than or equal to the decrease value, increase the spinning reserve rate of the power system.

3. The method for optimizing the spinning reserve rate of a wind power - integrated power system according to claim 2, wherein, Wherein, If the absolute value of the difference between the increase value and the decrease value is greater than a preset threshold, it is determined that there is a deviation between the increase value and the decrease value.

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