Power-frequency control method and system for hydropower-battery combined operation unit

Abstract

The present invention relates to power system frequency regulation control technology, and specifically to a power-frequency control method and system for a hydropower-battery co-operating unit. The control method involves three stages of the power-frequency control process of the frequency-regulating unit, namely, primary frequency regulation, secondary frequency regulation, and joint regulation control between primary and secondary frequency regulation. In the primary frequency regulation stage, the battery energy storage system adopts a virtual control strategy to assist conventional hydropower units in frequency regulation when the frequency deviation exceeds the frequency true regulation dead zone, and performs energy pullback when the frequency deviation re-enters the dead zone and meets certain conditions; in the secondary frequency regulation stage, the battery energy storage system adopts a difference compensation control method to assist conventional hydropower units in rapid power regulation; when primary and secondary frequency regulation instructions are received at the same time, the co-operating unit adopts a time-divided decoupling control strategy to avoid interference between control instructions. This method can help hydropower units and hydropower stations improve their own flexible regulation capabilities and alleviate the regulation burden of hydropower units.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system frequency regulation control, and in particular relates to a power-frequency control method and system for a hydropower-battery combined operation unit. Background Art

[0002] Hydropower is a type of high-quality power source in the power system. Its large capacity and flexible operation make it an important guarantee for the safe, stable and efficient operation of the power system. In the process of developing renewable energy, a development model of building a basin-type water, wind and solar multi-energy complementary base has been proposed. The role of hydropower is changing from a power supply to a power system regulator. It requires sufficient flexibility, durability and reliability to cope with random wind and solar output processes at any time. However, at the real-time control level focusing on the second time scale, this operation mode brings severe challenges to the operation of the hydropower system: one is the higher requirements for hydropower frequency regulation capabilities; the other is the heavier regulation burden of the hydropower system. In response to the above problems, the use of battery energy storage systems to assist in the regulation of hydropower systems may be an effective improvement measure. It is increasingly important to achieve the control goals of hydropower-battery joint operation safely, stably and efficiently.

[0003] The existing research on hydropower-battery combined operation control has the following main deficiencies: 1) Research object: Hydropower-battery combined operation units are a new type of hydropower flexibility transformation technology, and their integration mode, operation method and dynamic performance are yet to be studied; 2) Research focus: Most current research, especially on the localized integration of hydropower-batteries, discusses the joint control of hydropower stations and energy storage systems from the perspective of improving the frequency regulation capability of the power system, but rarely considers transformation measures at the unit level; 3) Control strategy: Existing research on the control strategy of hydropower-battery combined systems is almost entirely limited to the primary frequency regulation stage. However, the power-frequency control process of the frequency regulation system also includes multiple stages such as secondary frequency regulation and coordination of primary and secondary frequency regulation, which urgently need to be considered in an all-round way. Summary of the invention

[0004] The present invention provides a power-frequency control method and system for a hydropower-battery combined operation unit, which is used to solve the defect of frequency instability in the prior art caused by the continuous increase in the penetration rate of new energy to the power grid, improve the adjustment speed of conventional hydropower units, and effectively reduce the wear of hydropower units caused by frequent adjustments.

[0005] The present invention provides a power-frequency control method for a hydropower-battery combined operation unit, comprising the following steps:

[0006] S1 establishes a battery energy storage system based on virtual control technology to assist the primary frequency regulation control of hydropower units, including:

[0007] S1.1 treats the hydropower unit and the battery energy storage system as a combined unit for frequency response. The power controller of the battery energy storage system responds to the system frequency deviation at the synchronous generator bus of the hydropower unit. As the input value, the power feedback value of the speed regulator of the hydropower unit is the overall output power of the combined operation unit. ;

[0008] S1.2 establish primary frequency regulation control for hydropower units and battery energy storage system respectively;

[0009] S1.3 According to the system frequency deviation Whether it exceeds the frequency regulation dead zone , to pull back energy from the battery energy storage system;

[0010] S2 establishes secondary frequency regulation control of the battery energy storage system-assisted hydropower unit based on difference compensation control, including:

[0011] S2.1 puts the hydropower unit in power control mode, adopts PI type speed regulator, and sets the unit power regulation dead zone , set the interval time for sending commands ; The hydropower units in the combined operation units and the conventional hydropower units respond to the secondary frequency control instructions of the system The process is the same as;

[0012] S2.2 Formulate a power compensation control strategy for the battery energy storage system. When the hydropower unit responds to the power command, the actual output power of the hydropower unit With target instruction There is a difference, which is the power control target of the battery energy storage system. The battery energy storage system uses its power response to compensate for the output power of the combined operation unit.

[0013] S2.3 The hydropower unit and the battery energy storage system jointly respond to the secondary frequency modulation command. After the hydropower unit fully responds to the command, the output power of the battery energy storage system Gradually return to zero and prepare for the next auxiliary adjustment;

[0014] S3 uses a time-division decoupling control method to achieve coordinated control of primary and secondary frequency modulation, including:

[0015] The combined operation units only have a frequency deviation in the system The frequency regulation dead zone of the combined operation unit is less than that, and the unit switches to the secondary frequency regulation control during the initial period after the AGC command is put into operation. The unit is in the primary frequency regulation control mode during the rest of the time period.

[0016] According to a power-frequency control method for a hydropower-battery combined operation unit provided by the present invention, the primary frequency regulation control of the hydropower unit and the battery energy storage system is established separately, comprising:

[0017] S1.2.1 The primary frequency regulation control of the hydropower unit includes: the hydropower unit operates in power control mode and exceeds the frequency regulation dead zone System frequency deviation value According to the droop coefficient Converted into secondary frequency modulation control instructions , the sum of the power output of the hydropower unit and the battery energy storage system As the power feedback value of the speed regulator;

[0018] S1.2.2 The primary frequency regulation control of the battery energy storage system includes: exceeding the frequency regulation dead zone System frequency deviation Converted into power deviation signal according to virtual droop link and virtual inertia link ,Right now:

[0019]

[0020] in, is the virtual droop coefficient of the battery energy storage system, is the virtual inertia coefficient of the battery energy storage system, is a Laplace operator; the power control system adjusts the active power of the battery energy storage system according to the power deviation signal.

[0021] According to a power-frequency control method for a hydropower-battery combined operation unit provided by the present invention, the system frequency deviation Whether it exceeds the frequency regulation dead zone , energy recovery of the battery energy storage system includes:

[0022] S1.3.1 Set up an energy pullback controller, using a PI controller, where the control target is the ideal state of charge , the feedback value is the real-time state of charge of the battery energy storage system The output value of the energy pullback controller is the power adjustment value of the hydropower unit and the battery energy storage system. ;

[0023] S1.3.2 Setting the power adjustment value The rate limiter makes the power adjustment speed no greater than the real-time ramp rate of the hydropower unit; the power adjustment value after the rate limit As a target value, it is transmitted to the power control system of the battery energy storage system. It is synchronously input as the target value into the speed regulator of the hydropower unit in the power control mode;

[0024] S1.3.3 Set the energy pullback trigger condition and system frequency deviation Located in the frequency regulation dead zone The time within must be greater than a specific value ,when The time is greater than When , the energy pullback controller operates.

[0025] According to a power-frequency control method for a hydropower-battery combined operation unit provided by the present invention, the combined operation unit only has a power-frequency control method for a hydropower-battery combined operation unit. The frequency regulation dead zone of the combined operation unit is less than that of the combined operation unit, or the frequency regulation dead zone is switched to the secondary frequency regulation control in the initial period after the AGC command is put into operation, including:

[0026] Frequency deviation of the combined operation units in the system When the frequency is less than the dead zone of the frequency regulation of the combined operation unit, the secondary frequency regulation control is as follows: the frequency regulation unit does not perform frequency regulation, the primary frequency regulation process is not triggered, and the combined operation unit is based on the AGC power instruction of the automatic power control system. , that is, the hydropower unit tracks the target power and maintains a constant value according to the secondary frequency regulation power command;

[0027] In the initial period after the AGG instruction is put into operation, the secondary frequency control of the combined operation unit is as follows: Set the time threshold after the AGC instruction is put into operation , when the system issues a new AGC control command When the combined operation unit switches to the secondary frequency regulation mode and performs power tracking; when After a certain time, the combined operation unit responds to the power command of the system. If a small load disturbance occurs, the unit will adjust the frequency through the primary frequency regulation mode.

[0028] The present invention also provides a power-frequency control system for a hydropower-battery combined operation unit, the system comprising:

[0029] The primary frequency regulation control module is used to establish the primary frequency regulation control of the battery energy storage system-assisted hydropower unit based on virtual control technology;

[0030] A secondary frequency regulation control module is used to establish secondary frequency regulation control of the battery energy storage system-assisted hydropower unit based on difference compensation control;

[0031] The coordinated control module is used to realize the coordinated control of primary frequency modulation and secondary frequency modulation by adopting the time-division decoupling control method.

[0032] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a power-frequency control method for a hydropower-battery combined operation unit as described above is implemented.

[0033] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a power-frequency control method for a hydropower-battery combined operation unit as described in any one of the above.

[0034] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the power-frequency control method of any of the above-mentioned hydropower-battery combined operation units.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention is aimed at the new technical object of the combined operation unit integrating hydropower and battery as a whole, while taking into account the respective regulation characteristics and advantages of the hydropower unit and the battery energy storage system, and proposes a coordinated control method involving the whole process of power-frequency regulation, which includes three main stages: primary frequency regulation, secondary frequency regulation and joint regulation control between primary and secondary frequency regulation, and also considers the energy pullback of the battery energy storage system. This method can help hydropower units and hydropower stations improve their own flexible regulation capabilities, and alleviate the regulation burden of hydropower units, providing a new technical idea for the upgrading and transformation of hydropower systems. This method can effectively improve the regulation speed of conventional hydropower units, and at the same time can effectively reduce the wear of hydropower units caused by frequent regulation, and effectively deal with the frequency instability caused to the power grid due to the continuous increase in the penetration rate of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 is an operation schematic diagram of a hydropower-battery combined operation unit provided in an embodiment of the present invention;

[0038] Figure 2 This is a block diagram of primary frequency regulation control of a combined operation unit based on battery virtual control technology provided by an embodiment of the present invention;

[0039] Figure 3 is a block diagram of an energy pullback control loop of a battery energy storage system provided by an embodiment of the present invention;

[0040] FIG4 (a) is a response curve provided by an embodiment of the present invention when the No. 1 unit is a conventional hydropower unit;

[0041] FIG4( b ) is a response curve provided by an embodiment of the present invention when the No. 1 unit is transformed into a hydropower-battery combined operation unit;

[0042] Figure 5 It is a block diagram of secondary frequency regulation control of a combined operation unit based on difference compensation control provided by an embodiment of the present invention;

[0043] Figure 6 It is a secondary frequency modulation simulation response process of a hydropower-battery combined operation unit provided by an embodiment of the present invention;

[0044] Figure 7 It is a typical simulation response curve of the hydropower-battery combined operation unit provided in the embodiment of the present invention when performing primary and secondary frequency regulation and joint operation;

[0045] Figure 8 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] This embodiment proposes a power-frequency control method for a hydropower-battery combined operation unit. The method constructs a real-time operation control framework for the hydropower-battery combined operation unit, and proposes corresponding control methods for the battery energy storage system to assist the hydropower system in frequency regulation for the three stages of the single-machine power-frequency control process, namely, primary frequency regulation, secondary frequency regulation, and coordination of primary and secondary frequency regulation.

[0048] This embodiment is implemented by the following technical solution, a power-frequency control method of a hydropower-battery combined operation unit, comprising the following steps:

[0049] Step 1. Develop a primary frequency regulation control strategy for the battery energy storage system-assisted hydropower unit based on virtual control technology.

[0050] Step 1.1 The hydropower unit and the battery energy storage system are treated as a joint operation unit for frequency response. The power controller of the battery energy storage system is based on the system frequency deviation at the synchronous generator bus of the hydropower unit. As the input value, the power feedback value of the speed regulator is the overall output power of the combined operation unit. .

[0051] Step 1.2: Design a frequency regulation control strategy for the hydropower unit and the battery energy storage system respectively:

[0052] 1) For hydropower units: The hydropower units are running in power control mode and exceed the frequency regulation dead zone. System frequency deviation value According to the droop coefficient Converted into secondary frequency modulation control instructions , the sum of the power output of the hydropower unit and the battery energy storage system As the power feedback value of the speed regulator;

[0053] 2) For battery energy storage systems: exceeding the frequency regulation dead zone System frequency deviation value Convert the virtual droop link and virtual inertia link into a power deviation signal ,Right now:

[0054]

[0055] in, is the virtual droop coefficient of the battery energy storage system, is the virtual inertia coefficient of the battery energy storage system, is the Laplace operator. The power control system (PCS) will adjust the active power of the battery energy storage system according to the power deviation signal.

[0056] Step 1.3 Based on the system frequency deviation Whether it exceeds the frequency regulation dead zone Pull back energy from the battery energy storage system;

[0057] Step 1.3.1 Set up the energy pullback controller, using a PI control strategy where the control target is the ideal state of charge , the feedback value is the real-time state of charge of the battery energy storage system The controller output value is the power adjustment value of the hydropower unit and the battery energy storage system .

[0058] Step 1.3.2 Set the power adjustment value The rate limiter is used to adjust the power speed no faster than the real-time ramp rate of the hydropower unit. To maintain the power balance of the combined units, the power adjustment value after the rate limit is The target value is transmitted to the power control system PCS of the battery energy storage system. It will be synchronously input as the target value into the speed regulator of the hydropower unit in power control mode.

[0059] Step 1.3.3 Set the energy pullback trigger condition. In order not to affect the frequency regulation process of the combined operation unit, the system frequency deviation is in the frequency regulation dead zone. The time within must be greater than a specific value , that is, only when The time is greater than The energy pullback controller will only operate when

[0060] Step 2. Develop a secondary frequency regulation control strategy for the battery energy storage system-assisted hydropower unit based on difference compensation control.

[0061] In actual engineering applications, if a hydropower generating unit operates in power control mode, the actual power control instructions given to the unit by the superior dispatching agency are often not continuous, but a series of step instructions obtained through isochronous sampling based on the actual power deficit curve, that is, automatic generation control AGC (automatic power control system) instructions. Therefore, the secondary frequency regulation process of the hydropower unit is actually equivalent to a power step response at regular intervals.

[0062] Step 2.1 Formulate the secondary frequency control strategy for the hydropower unit. The hydropower unit is in power control mode and uses a PI type speed regulator to set the unit power regulation dead zone. To avoid frequent actions of the unit, set the interval time for sending instructions At this time, the hydropower units in the joint operation unit and the conventional hydropower units respond to the secondary frequency control command of the system The process is no different.

[0063] Step 2.2: Develop a power compensation control strategy for the battery energy storage system. When the hydropower unit responds to the power command, the actual output power of the hydropower unit With target instruction There is a difference, which is the power control target of the battery energy storage system. The battery energy storage system will use its rapid power response to compensate for the output power of the combined operation unit.

[0064] Step 2.3 The hydropower unit and the battery energy storage system jointly respond to the secondary frequency modulation command. After the hydropower unit fully responds to the command, the output power of the battery energy storage system Gradually return to zero and prepare for the next auxiliary adjustment.

[0065] Step 3. Use the time-division decoupling control method to achieve coordinated control of primary frequency modulation and secondary frequency modulation.

[0066] The control logic of primary frequency regulation and secondary frequency regulation of the combined operation unit is different, so the combined operation unit cannot achieve a simple superposition of primary frequency regulation and secondary frequency regulation signals; for the frequency regulation control process of the hydropower unit, there is also a situation where the primary frequency regulation and AGC control process cannot be unified. Therefore, considering that the main action time of the primary frequency regulation and the secondary frequency regulation do not overlap, and the adjustment targets have different focuses, the present invention sets a control strategy of time-division decoupling.

[0067] The combined operation units can only switch to the secondary frequency regulation control strategy in the following two situations. In the rest of the time period, the combined operation units are in the primary frequency regulation control mode:

[0068] 1) System frequency deviation Less than the frequency dead zone of the combined operation units;

[0069] At this time, the frequency regulating unit does not need to perform frequency regulation, and the frequency regulation process is not triggered. The joint operation unit needs to follow the AGC power instruction. , that is, the hydropower unit tracks the target power and maintains a constant value according to the secondary frequency regulation power instruction.

[0070] 2) During the initial period after the AGC instruction is put into use;

[0071] Set the time threshold after the AGC instruction is put into use , when the AGC control command issued by the system When the combined operation unit needs to immediately switch to the secondary frequency regulation mode and perform power tracking; when experiencing After a certain time, the combined operation unit has basically fully responded to the system power command. If a small load disturbance occurs at this time, the unit can adjust the frequency through the primary frequency regulation mode.

[0072] In the specific implementation, the power-frequency control of the combined operation unit composed of a Francis turbine generator set and a lithium-ion energy storage battery is used as a detailed description of this implementation method:

[0073] This embodiment is explained by a simulation model of a multi-energy complementary energy base containing a multi-machine hydropower station. The base is connected to the external power grid through a connecting line, and it is assumed that one of the hydropower stations contains the novel hydropower-battery combined operation unit. In this virtual simulation system, the multi-energy complementary energy base contains a hydropower station, a thermal power station, a photovoltaic power station and a wind farm. A 5MW battery energy storage system is connected in parallel to one of the 250MW mixed flow hydropower units in the target hydropower station to assist in regulation. The framework of the hydropower-battery combined operation unit is shown in the figure below. Figure 1 shown.

[0074] Step (1): Develop a primary frequency regulation control strategy for the battery energy storage system-assisted hydropower unit based on virtual control technology.

[0075] The block diagram of the primary frequency regulation control strategy of the combined operation unit based on battery virtual control technology is as follows Figure 2 System frequency deviation signal After the virtual droop link and virtual inertia link, it is converted into the power control signal of the battery energy storage system , PCS controls the output power of the energy storage battery Output power of hydropower unit The superposition together adjusts the frequency of the system.

[0076] Without considering the effect of the speed governor, that is, without considering the influence of the primary frequency regulation characteristics of the hydropower unit, due to its rotational inertia, the frequency response characteristics of the hydropower unit are:

[0077]

[0078] in, is the system frequency deviation, is the unit inertia time constant, is the damping coefficient, is the output power of the hydropower unit, is the load disturbance power, is the Laplace operator. In this embodiment, , .

[0079] Virtual control technology uses PCS to simulate the droop and inertia characteristics of synchronous motors so that energy storage batteries also have the ability to suppress system frequency deviations similar to synchronous motors. The present invention achieves this goal through a PD controller. When auxiliary batteries are configured, without considering nonlinear characteristics such as the dead zone of battery frequency regulation, the frequency response characteristics of the combined operation unit become:

[0080]

[0081] in, and are the virtual droop coefficient and virtual inertia coefficient of the battery, is the system frequency deviation, is the unit inertia time constant, is the damping coefficient, is the combined operating unit output power, is the load disturbance power, is the Laplace operator. In this embodiment, , The above formula shows that the inertia characteristic of the combined operation unit becomes , and the damping becomes It can be seen that virtual control technology can improve the unit from the inherent frequency response characteristics of the system. The energy pullback control loop of the battery energy storage system is as follows: Figure 3 shown.

[0082] Figure 4 (a) is the response curve when Unit 1# is a conventional hydropower unit, and Figure 4 (b) is the response curve when Unit 1# is converted into a hydropower-battery combined operation unit. As can be seen from Figure 4 (a), although the base frequency is finally kept stable due to the external large power grid, the reverse adjustment caused by the inertia of the water diversion system causes the conventional hydropower unit to start the next round of adjustment action due to the frequency oscillation phenomenon before the last frequency adjustment instruction is completed, and then the power change direction and the frequency change direction are unexpectedly kept consistent, which is very unfavorable for maintaining frequency stability and should be avoided as much as possible. In contrast, in Figure 4 (b), due to the rapid power support provided by the battery to offset the reverse adjustment of the hydropower unit, the power change direction and the frequency change direction of the combined operation unit show an obvious synchronous reverse trend, thereby suppressing the frequency fluctuation. This is also the fundamental reason why the combined operation unit can improve the system frequency regulation performance.

[0083] Step (2): Formulate a secondary frequency regulation control strategy for the battery energy storage system-assisted hydropower unit based on difference compensation control;

[0084] The block diagram of the secondary frequency regulation control strategy of the combined operation unit based on difference compensation control is as follows: Figure 5 The energy storage battery control loop in the combined operation unit is actually an open-loop control process, which means that the hydropower unit in the combined operation unit is no different from other conventional units in the system.

[0085] The hydropower unit can respond to the secondary frequency control command of the system in its conventional power control mode, that is, . Due to the inertia effect and water hammer effect of the hydropower unit, it cannot achieve the effect of instantaneous tracking, resulting in a dynamic power deviation. At this time, the battery energy storage system uses its rapid power response to compensate for the difference to assist the combined operation unit to achieve rapid power tracking. The output of the battery energy storage system will eventually return to zero due to the full response of the hydropower unit output, while also allowing the energy storage battery to avoid continuous power output. In this embodiment, the power regulation dead zone is taken , command sending interval .

[0086] Figure 6It is the secondary frequency regulation response process of the hydropower-battery combined operation unit. When facing the AGC control command corresponding to the step, in the initial stage of the disturbance, since the hydropower unit has not yet taken action and will undergo the reverse regulation response process, the hydropower unit has a large deviation at this time, which acts on the energy storage battery to make it output at the rated power, which can offset the reverse power to a certain extent, but whether it can be completely offset depends on the rated capacity of the battery; in the unit climbing stage, the hydropower unit itself can climb faster, and the superimposed battery rated power at this time helps to reduce the actual power deviation of the combined operation unit; in the approaching target stage, since the hydropower unit deviation is already less than the rated power of the energy storage battery at this time, the energy storage battery can quickly track the hydropower unit deviation within the controllable range, and stable tracking can be achieved after the power of the combined operation unit reaches the target power, which not only significantly increases the speed of the adjustment process, but also does not cause overshoot.

[0087] Step (3): Use the time-division decoupling control method to achieve coordinated control of primary and secondary frequency modulation

[0088] According to the main regulation purposes of primary frequency modulation and secondary frequency modulation, the control logic is set as follows:

[0089] 1) Every time a new control command is received, the combined operation unit first tracks the new power command through the secondary frequency control mode;

[0090] 2) After time, that is, after the unit has mostly responded to the power command, it switches to the primary frequency modulation control mode for fine-tuning;

[0091] 3) When the system frequency deviates Enter the set frequency adjustment dead zone After that, the combined operation unit switches to the secondary frequency control mode, so that the unit responds to the AGC power command and maintains a constant value, preparing for the next AGC power command;

[0092] In this embodiment, , .

[0093] Figure 7 This is a representative power response curve of the combined operation unit after adopting the control framework proposed by this method. Figure 7As shown, at about 225s, the combined operation unit received the previous power command, quickly entered the secondary frequency regulation control mode, and quickly responded to the unit output with a deviation of about 0.022pu. Soon after, most of the units responded to the power command; at about 231s, the unit switched to the primary frequency regulation control mode to respond to the system frequency. When the system frequency deviation was small enough, that is, at about 238s, the combined operation unit switched to the secondary frequency regulation control mode and continued to maintain the unit power change at around 0.022pu; at 240s, the unit received the next power command and continued to respond to the command quickly, thereby realizing the coordinated operation of the primary and secondary frequency regulation of the hydropower-battery combined operation unit.

[0094] This embodiment also provides a power-frequency control system for a hydropower-battery combined operation unit, including:

[0095] The primary frequency regulation control module is used to establish the primary frequency regulation control of the battery energy storage system-assisted hydropower unit based on virtual control technology;

[0096] A secondary frequency regulation control module is used to establish secondary frequency regulation control of the battery energy storage system-assisted hydropower unit based on difference compensation control;

[0097] The coordinated control module is used to realize the coordinated control of primary frequency modulation and secondary frequency modulation by adopting the time-division decoupling control method.

[0098] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor, a communications interface, a memory, and a communications bus, wherein the processor, the communications interface, and the memory communicate with each other via the communications bus. The processor may call the logic instructions in the memory to execute the power-frequency control method of the hydropower-battery combined operation unit.

[0099] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, 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, which is stored in a storage medium and includes 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 method 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 code.

[0100] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the power-frequency control method of the hydropower-battery combined operation unit provided by the above methods.

[0101] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the power-frequency control method of the hydropower-battery combined operation unit provided by the above-mentioned methods.

[0102] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0103] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power-frequency control method for a hydropower-battery combined operation unit, characterized in that: The following steps are involved: S1 establishes a battery energy storage system based on virtual control technology to assist the primary frequency regulation control of hydropower units, including: S1.1 treats the hydropower unit and the battery energy storage system as a combined unit for frequency response. The power controller of the battery energy storage system responds to the system frequency deviation at the synchronous generator bus of the hydropower unit. As the input value, the power feedback value of the speed regulator of the hydropower unit is the overall output power of the combined operation unit. ; S1.2 establish primary frequency regulation control for hydropower units and battery energy storage system respectively; S1.3 According to the system frequency deviation Whether it exceeds the frequency regulation dead zone , to pull back energy from the battery energy storage system; S2 establishes secondary frequency regulation control of the battery energy storage system-assisted hydropower unit based on difference compensation control, including: S2.1 puts the hydropower unit in power control mode, adopts PI type speed regulator, and sets the unit power regulation dead zone , set the interval time for sending commands ; The hydropower units in the combined operation units and the conventional hydropower units respond to the secondary frequency control instructions of the system The process is the same as; S2.2 Formulate a power compensation control strategy for the battery energy storage system. When the hydropower unit responds to the power command, the actual output power of the hydropower unit With target instruction There is a difference, which is the power control target of the battery energy storage system. The battery energy storage system uses its power response to compensate for the output power of the combined operation unit. S2.3 The hydropower unit and the battery energy storage system jointly respond to the secondary frequency modulation command. After the hydropower unit fully responds to the command, the output power of the battery energy storage system Gradually return to zero and prepare for the next auxiliary adjustment; S3 uses a time-division decoupling control method to achieve coordinated control of primary and secondary frequency modulation, including: The combined operation units only have a frequency deviation in the system The frequency regulation dead zone of the combined operation unit is less than that of the unit, or the unit switches to the secondary frequency regulation control during the initial period after the AGC command is put into operation. The unit is in the primary frequency regulation control mode during the rest of the time period.

2. The power-frequency control method of the hydropower-battery combined operation unit according to claim 1, characterized in that: The primary frequency regulation control of the hydropower unit and the battery energy storage system is established separately, including: S1.2.1 The primary frequency regulation control of the hydropower unit includes: the hydropower unit operates in power control mode and exceeds the frequency regulation dead zone System frequency deviation value According to the droop coefficient Converted into secondary frequency modulation control instructions , the sum of the power output of the hydropower unit and the battery energy storage system As the power feedback value of the speed regulator; S1.2.2 The primary frequency regulation control of the battery energy storage system includes: exceeding the frequency regulation dead zone System frequency deviation Converted into power deviation signal according to virtual droop link and virtual inertia link ,Right now: in, is the virtual droop coefficient of the battery energy storage system, is the virtual inertia coefficient of the battery energy storage system, is a Laplace operator; the power control system adjusts the active power of the battery energy storage system according to the power deviation signal.

3. The power-frequency control method of the hydropower-battery combined operation unit according to claim 2, characterized in that: According to the system frequency deviation Whether it exceeds the frequency regulation dead zone , energy recovery of the battery energy storage system includes: S1.3.1 Set up an energy pullback controller, using a PI controller, where the control target is the ideal state of charge , the feedback value is the real-time state of charge of the battery energy storage system The output value of the energy pullback controller is the power adjustment value of the hydropower unit and the battery energy storage system. ; S1.3.2 Setting the power adjustment value The rate limiter makes the power adjustment speed no greater than the real-time ramp rate of the hydropower unit; the power adjustment value after the rate limit As a target value, it is transmitted to the power control system of the battery energy storage system. It is synchronously input as the target value into the speed regulator of the hydropower unit in the power control mode; S1.3.3 Set the energy pullback trigger condition, system frequency deviation Located in the frequency regulation dead zone The time within must be greater than a specific value ,when The time is greater than When , the energy pullback controller operates.

4. The power-frequency control method of the hydropower-battery combined operation unit according to claim 1, characterized in that: The combined operation unit is only The frequency regulation dead zone of the combined operation unit is less than that of the combined operation unit, or the frequency regulation dead zone is switched to the secondary frequency regulation control in the initial period after the AGC command is put into operation, including: Frequency deviation of the combined operation units in the system When the frequency is less than the dead zone of the frequency regulation of the combined operation unit, the secondary frequency regulation control is as follows: the frequency regulation unit does not perform frequency regulation, the primary frequency regulation process is not triggered, and the combined operation unit is based on the AGC power instruction of the automatic power control system. , that is, the hydropower unit tracks the target power and maintains a constant value according to the secondary frequency regulation power command; In the initial period after the AGG instruction is put into operation, the secondary frequency control of the combined operation unit is as follows: Set the time threshold after the AGC instruction is put into operation , when the system issues a new AGC control command When the combined operation unit switches to the secondary frequency regulation mode and performs power tracking; when After a certain time, the combined operation unit responds to the power command of the system. If a small load disturbance occurs, the unit will adjust the frequency through the primary frequency regulation mode.

5. A power-frequency control system for a hydropower-battery combined operation unit, characterized in that: The system is used to implement the power-frequency control method of the hydropower-battery combined operation unit according to any one of claims 1 to 4; comprising: The primary frequency regulation control module is used to establish the primary frequency regulation control of the battery energy storage system-assisted hydropower unit based on virtual control technology; A secondary frequency regulation control module is used to establish secondary frequency regulation control of the battery energy storage system-assisted hydropower unit based on difference compensation control; The coordinated control module is used to realize the coordinated control of primary frequency modulation and secondary frequency modulation by adopting the time-division decoupling control method.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the power-frequency control method of the hydropower-battery combined operation unit as described in any one of claims 1 to 4 is implemented.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the power-frequency control method of the hydropower-battery combined operation unit as claimed in any one of claims 1 to 4 is implemented.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the power-frequency control method of the hydropower-battery combined operation unit as claimed in any one of claims 1 to 4 is implemented.

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