New energy station primary frequency modulation control method and system

Abstract

The invention relates to the technical field of power system analysis and control, in particular to a primary frequency modulation control method and system for a new energy station, and the method comprises the steps: calculating and judging whether a grid-connected point frequency value is between an upper limit and a lower limit of a primary frequency modulation dead zone according to a load frequency relation, if yes, forwarding an execution unit; judging whether the grid-connected point frequency value is between a primary frequency modulation allowable minimum value and a primary frequency modulation dead zone upper limit, if so, calculating an active power vacancy value of the new energy station and a primary frequency modulation power target value of the new energy station, and forwarding to an execution unit; and judging whether the grid-connected point frequency value is between the primary frequency modulation dead zone lower limit and the primary frequency modulation allowable maximum value, if so, calculating the active power vacancy value of the new energy station and the primary frequency modulation power target value of the new energy station, and forwarding to the execution unit, and if not, stopping the execution unit. The system frequency drop is reduced, the stability of the power grid frequency and the system robustness are improved, and a new guidance method is provided for primary frequency modulation control of an energy field station.

Description

Technical Field

[0001] The present invention relates to the technical field of power system analysis and control, and in particular to a primary frequency regulation control method and system for a new energy station. Background Art

[0002] In recent years, with the intensification of the global energy crisis and the emergence of environmental problems, new energy power generation technologies represented by wind and light have received more and more attention. Unlike traditional synchronous generators, the output of new energy has a certain degree of randomness and volatility. The large-scale grid connection of new energy power generation devices has brought a large amount of power disturbance to the system, which has increased the frequency regulation demand of the system. Limited by the capacity and regulation speed of the units, the frequency regulation capacity of the synchronous units in the system is limited. In order to pursue high primary energy utilization, new energy units are needed for frequency regulation. If the new energy units cannot participate in the system frequency regulation, the system may face the problem of insufficient frequency regulation capacity and excessive steady-state frequency deviation.

[0003] Frequency, as an important indicator of power quality, plays an important role in the safe and stable operation of the power system. Therefore, controlling frequency fluctuations within a small range is one of the main goals of the safe and stable operation of the power system. Coal-fired power units ignore the load frequency characteristics in the primary frequency regulation due to their large capacity, large moment of inertia, and small system frequency fluctuations. After large-capacity and high-proportion new energy sources were connected to the power grid, the power structure has changed greatly. The proportion of traditional power grid frequency response resources has gradually decreased, and the pressure of frequency regulation and the risk of safe operation have continued to increase. There is an urgent need for new energy to participate in the rapid response of the power grid and improve the level of frequency risk prevention and control of large power grids. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention is proposed.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions, a new energy station primary frequency regulation control method, comprising:

[0006] List expressions based on load-frequency relationships;

[0007] Make a judgment to determine whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency modulation dead zone;

[0008] A second judgment is made based on the result of the first judgment.

[0009] As a preferred solution of the primary frequency regulation control method of a new energy station described in the present invention, the expression listed according to the load-frequency relationship is expressed as:

[0010]

[0011] Among them, P loadIndicates the active power corresponding to the system frequency f, P loadN Indicates that the system frequency is f N The corresponding active power, a0, a i They are the types of loads P loadN The proportionality coefficient is n, n is the number of load types, f is the system frequency, f N is the rated frequency of the system.

[0012] As a preferred scheme of the primary frequency regulation control method of a new energy station described in the present invention, wherein: the judgment of whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency regulation dead zone includes, if yes, forwarding to the execution unit; if not, judging whether the frequency value of the grid connection point is between the minimum allowable value of the primary frequency regulation and the upper limit of the primary frequency regulation dead zone; if yes, calculating the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station, and forwarding to the execution unit.

[0013] As a preferred solution of the primary frequency regulation control method of a new energy station described in the present invention, if the grid connection point frequency value is between the upper and lower limits of the primary frequency regulation dead zone, that is, the grid connection point frequency satisfies f min <f<f l , adjust the active power shortage of the primary frequency regulation of the new energy station, expressed as:

[0014]

[0015] Among them, ΔP l is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f l It is the upper limit of the primary frequency modulation dead zone;

[0016] The target value of primary frequency regulation power of new energy stations is:

[0017] P l1 =P0+ΔP lmax

[0018] Among them, P l1 is the target value of the primary frequency regulation power of the new energy station, P0 is the initial value of active power, ΔP lmax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

[0019] As a preferred scheme of the primary frequency regulation control method of a new energy station described in the present invention, the secondary judgment includes judging whether the frequency value of the grid connection point is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation. If so, the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station are calculated and forwarded to the execution unit. If not, the execution unit does not act.

[0020] As a preferred solution of the primary frequency regulation control method of a new energy station described in the present invention, if the grid connection point frequency value is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation, that is, the grid connection point frequency satisfies f u <f<f max , adjust the active power shortage of primary frequency regulation at new energy stations.

[0021] As a preferred solution of the primary frequency regulation control method of a new energy station described in the present invention, wherein: the adjustment of the primary frequency regulation active power shortage of the new energy station is expressed as:

[0022]

[0023] Among them, ΔP u is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f u It is the upper limit of the primary frequency modulation dead zone.

[0024] The target value of primary frequency regulation power of new energy stations is:

[0025] P u1 =P0-ΔP umax

[0026] Among them, P u1 is the target value of primary frequency regulation power of new energy station, ΔP umax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

[0027] As a preferred solution of the primary frequency regulation control system of a new energy station described in the present invention, it includes: a calculation module, a primary judgment module, and a secondary judgment module.

[0028] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and wherein the processor implements the steps of any one of the methods for primary frequency regulation control of a new energy station when executing the computer program.

[0029] 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 any one of the methods described in a primary frequency regulation control method for a new energy station are implemented.

[0030] Beneficial effects of the invention: The present invention proposes a primary frequency regulation control method for a new energy station. The participation of new energy stations in the primary frequency regulation of the power grid is rapid, but its output is unstable. The participation of new energy stations in the primary frequency regulation of the power grid mostly adopts the active power-frequency droop control method, but does not consider the impact of load frequency characteristics on the participation of new energy stations in the primary frequency regulation of the power grid. As the proportion of new energy stations as primary frequency regulation power sources in the power grid gradually increases, compared with traditional thermal power, the addition of new energy stations reduces the reliability of the primary frequency regulation of the power grid. Therefore, it is of great significance to consider the frequency characteristics of the load. Aiming at the shortcomings of the conventional primary frequency regulation mechanism of new energy stations, the present invention considers the impact of load frequency characteristics on primary frequency regulation on the basis of conventional primary frequency regulation, optimizes the primary frequency regulation method, reduces the system frequency drop, enhances the anti-disturbance ability of the system frequency, and improves the stability of the system frequency, providing a new guidance method for primary frequency regulation control of energy stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 A flow chart of a primary frequency regulation control method for a new energy station provided in accordance with an embodiment of the present invention.

[0033] Figure 2 A schematic diagram of system frequency comparison before and after low-frequency primary frequency regulation optimization of a primary frequency regulation control method for a new energy station provided by an embodiment of the present invention.

[0034] Figure 3 A schematic diagram of system frequency comparison before and after high-frequency primary frequency regulation optimization of a primary frequency regulation control method for a new energy station provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Reference Figure 1-Figure 3, which is the first embodiment of the present invention, and provides a primary frequency modulation control method for a new energy station, comprising:

[0038] like Figure 1 As shown, a method for primary frequency regulation control of a new energy station is shown, and the steps are as follows:

[0039] Step 1: List the expressions based on the load-frequency relationship. Ignoring voltage fluctuations, the relationship between system frequency and load active power is:

[0040]

[0041] Among them, P load Indicates the active power corresponding to the system frequency f, P loadN Indicates the active power corresponding to the system frequency fN, a0, a i They are the types of loads P loadN The proportionality coefficient is n, n is the number of load types, f is the system frequency, f N is the rated frequency of the system.

[0042] Step 2: Determine whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency regulation dead zone. If so, forward it to the execution unit. If not, determine whether the frequency value of the grid connection point is between the minimum value allowed by the primary frequency regulation and the upper limit of the primary frequency regulation dead zone. If so, calculate the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station, and forward it to the execution unit.

[0043] If the grid connection point frequency value is between the upper and lower limits of the primary frequency modulation dead zone, that is, the grid connection point frequency satisfies f min <f<f l At this time, the active power deficit of the primary frequency regulation of the new energy station is adjusted to:

[0044]

[0045] Among them, ΔP l is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f l It is the upper limit of the primary frequency modulation dead zone.

[0046] The target value of primary frequency regulation power of new energy stations is:

[0047] P l1 =P0+ΔP lmax

[0048] Among them, P l1 is the target value of the primary frequency regulation power of the new energy station, P0 is the initial value of active power, ΔP lmax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

[0049] If f<f min The maximum active power shortage of the new energy station in the primary frequency regulation is the maximum adjustment amount of the current active power increase of the new energy station.

[0050] Step 3: Determine whether the frequency value of the grid connection point is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation. If so, calculate the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station, and forward it to the execution unit. If not, the execution unit does not act.

[0051] If the frequency value of the grid connection point is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation, that is, the grid connection point frequency satisfies f u <f<f max At this time, the active power deficit of the primary frequency regulation of the new energy station is adjusted to:

[0052]

[0053] Among them, ΔP u is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f u It is the upper limit of the primary frequency modulation dead zone.

[0054] The target value of primary frequency regulation power of new energy stations is:

[0055] P u1 =P0-ΔP umax

[0056] Among them, P u1 is the target value of primary frequency regulation power of new energy station, ΔP umax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

[0057] If f>f max The maximum active power surplus of the new energy station in the first frequency regulation is the maximum regulation amount of the current active power reduction of the new energy station.

[0058] The following is an explanation with reference to a specific example, using two inverter-type micro power sources for comparative verification, one of which uses conventional droop control for primary frequency modulation control method, and the other uses the optimized primary frequency modulation control method proposed in this article that takes into account the load frequency characteristics. The simulation time is set to 4s. At t=0~4s, the lighting load P1=10kW and the air-conditioning load P2=20kW are connected. The lighting load is independent of the frequency, and the air-conditioning load is proportional to the first power of the frequency. At t=1.5s, the motor load P3=25kW is connected, and the motor load is proportional to the third power of the frequency. At t=0~2.5s, the system is in grid-connected mode, and at t=2.5~4s, the system is in off-grid mode. Using the method proposed in this invention, the results are as follows: Figure 2-Figure 3 As shown, it can be seen that no matter it is low-frequency primary frequency modulation or high-frequency primary frequency modulation, the system frequency after optimization is significantly improved compared with before optimization, which verifies the effectiveness of the method proposed in the present invention.

[0059] Example 2

[0060] The second embodiment of the present invention is different from the previous embodiment in that:

[0061] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0062] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0063] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0064] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0065] Example 3

[0066] The third embodiment of the present invention provides a primary frequency regulation control system for a new energy station, which is characterized by comprising a calculation module, a primary judgment module, and a secondary judgment module.

[0067] The calculation module lists the expressions according to the load-frequency relationship;

[0068] A primary judgment module performs a primary judgment to determine whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency modulation dead zone;

[0069] The secondary judgment module performs secondary judgment based on the result of the primary judgment.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A primary frequency modulation control method for a new energy station, characterized in that: include, List expressions based on load-frequency relationships; Make a judgment to determine whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency modulation dead zone; A second judgment is made based on the result of the first judgment.

2. A new energy station primary frequency modulation control method as claimed in claim 1, characterized in that: The expression listed according to the load-frequency relationship is expressed as: Among them, P load Indicates the active power corresponding to the system frequency f, P loadN Indicates the active power corresponding to the system frequency fN, a0, a i They are the types of loads P loadN The proportionality coefficient is n, n is the number of load types, f is the system frequency, f N is the rated frequency of the system.

3. A new energy station primary frequency modulation control method as claimed in claim 2, characterized in that: The method of judging whether the frequency value of the grid connection point is between the upper and lower limits of the primary frequency regulation dead zone includes: if so, forwarding to the execution unit; if not, judging whether the frequency value of the grid connection point is between the minimum value allowed by the primary frequency regulation and the upper limit of the primary frequency regulation dead zone; if so, calculating the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station, and forwarding to the execution unit.

4. A new energy station primary frequency modulation control method as claimed in claim 3, characterized in that: If the grid connection point frequency value is between the upper and lower limits of the primary frequency modulation dead zone, that is, the grid connection point frequency satisfies f min <f<f l , adjust the active power shortage of the primary frequency regulation of the new energy station, expressed as: Among them, ΔP l is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f l It is the upper limit of the primary frequency modulation dead zone; The target value of primary frequency regulation power of new energy stations is: P l1 =P0+ΔP lmax Among them, P l1 is the target value of the primary frequency regulation power of the new energy station, P0 is the initial value of active power, ΔP lmax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

5. A new energy station primary frequency modulation control method as claimed in claim 4, characterized in that: The secondary judgment includes judging whether the frequency value of the grid connection point is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation. If so, calculating the active power shortage value of the new energy station and the primary frequency regulation power target value of the new energy station, and forwarding it to the execution unit. If not, the execution unit does not act.

6. A new energy station primary frequency modulation control method as claimed in claim 5, characterized in that: If the frequency value of the grid connection point is between the lower limit of the primary frequency regulation dead zone and the maximum value allowed by the primary frequency regulation, that is, the grid connection point frequency satisfies f u <f<f max , adjust the active power shortage of primary frequency regulation at new energy stations.

7. A new energy station primary frequency modulation control method as claimed in claim 6, characterized in that: The adjustment of the primary frequency regulation active power deficit of the new energy station is expressed as: Among them, ΔP u is the active power shortage of the primary frequency regulation of the new energy station, δ is the frequency regulation error rate of the primary frequency regulation of the new energy station, and f u It is the upper limit of the primary frequency modulation dead zone. The target value of primary frequency regulation power of new energy stations is: P u1 =P0-ΔP umax Among them, P u1 is the target value of primary frequency regulation power of new energy station, ΔP umax It is the maximum power shortage calculated when the primary frequency deviation of the current new energy station is the largest.

8. A system based on a primary frequency modulation control method for a new energy station according to any one of claims 1 to 7, characterized in that: It includes a calculation module, a primary judgment module, and a secondary judgment module.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. 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 method according to any one of claims 1 to 7 are implemented.

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