Hydropower station multi-unit isolated network operation and frequency control method and system

Abstract

The invention discloses a hydropower station multi-unit isolated network operation and frequency control method and system, and relates to the technical field of power system frequency control, and the method comprises the steps: determining the number of units connected to an isolated network according to the total capacity of the isolated network, and distributing unit roles; adjusting unit frequency through a first strategy, and transferring load through a first method; and optimizing the isolated network system based on the isolated network parameters. According to the hydropower station multi-unit isolated network operation and frequency control method provided by the invention, the operation stability of the system is improved by setting the graded frequency dead zones on the speed regulators of the frequency modulation units, and the anti-interference capability and stability of the system are improved by transferring the load between the frequency modulation units and monitoring and avoiding the vibration zones; the difference adjustment rate and the frequency dead zone of the unit are set to be 0, it is ensured that the system can still maintain the stable frequency when the load is low, the economical efficiency and the operation efficiency of the isolated network system are improved, and better effects are achieved in the aspects of stability, economical efficiency and operation efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of power system frequency control, and in particular to a method for isolated grid operation and frequency control of multiple units in a hydropower station. Background Art

[0002] In modern power systems, power grids usually rely on wide area networks to achieve stable power supply and load distribution. However, in some special circumstances, such as power grid maintenance, natural disasters or independent power supply needs in remote areas, the power system may be divided into isolated grids, that is, small networks independent of the main grid. In isolated grid operation, the frequency and voltage of the system are easily affected by external disturbances and load changes, which puts higher requirements on power stability. At present, hydropower stations are widely used in power supply under isolated grid mode. Since the speed regulators and monitoring systems of hydropower stations have good regulation capabilities and response speeds, they play a key role in maintaining frequency stability and load balance in isolated grids. In recent years, in order to cope with the complex operating conditions under isolated grid mode, power regulation technology and frequency control methods have gradually developed, but still face many technical bottlenecks.

[0003] At present, the frequency control in the isolated grid mode of the hydropower station mainly relies on the method of single unit carrying load. The regulation ability of this method can barely achieve basic frequency stability in the isolated grid system with small load demand, but it exposes obvious deficiencies in the larger isolated grid that requires multiple units to carry load together. First, the existing technology lacks an effective control method for the load distribution of multi-unit isolated grids, which easily leads to load fluctuations between units and may even cause frequency oscillation, making it difficult for the system to remain stable. Secondly, the control of a single speed regulator cannot coordinate the operation of multiple units. When the frequency fluctuates greatly, asynchronous operation may occur between the units, such as some units are in power generation mode, while other units accidentally enter the phase adjustment state, which seriously affects the stability of the system. In addition, the existing frequency control technology mainly relies on manual adjustment, does not have dynamic automatic adjustment function, and lacks the ability to adapt to abnormal states such as vibration zone and phase adjustment, making it difficult for the system to adjust to a stable state in time when the frequency deviates greatly, posing a safety hazard. Therefore, the existing technology cannot meet the needs of accurate frequency regulation and coordinated operation of multiple units under complex isolated grid conditions. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing cloud service platform calculation method has the problems of unclear load distribution between units, large frequency fluctuations, lack of dynamic automatic adjustment function, and how to optimize the stability of frequency control in multi-unit isolated network mode.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for isolated grid operation and frequency control of multiple units in a hydropower station, comprising determining the number of units to be incorporated into the isolated grid according to the total capacity of the isolated grid and allocating the roles of the units; adjusting the unit frequency through a first strategy and transferring the load through a first method; and optimizing the isolated grid system based on the isolated grid parameters.

[0007] As a preferred scheme of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the method of determining the number of units to be connected to the isolated grid according to the total capacity of the isolated grid includes determining the number of units to be connected to the isolated grid according to the total capacity of the isolated grid, and adjusting the power of the units.

[0008] As a preferred solution of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the allocation of unit roles includes comparing the total capacity of part of the isolated grid with the capacity of a single unit to allocate the unit roles.

[0009] As a preferred solution of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the frequency adjustment of the units through the first strategy includes stabilizing the frequency fluctuation of the isolated grid system by limiting the integral output and change rate of the frequency deviation.

[0010] As a preferred solution of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the load transfer by the first method includes transferring the load by the first method when an abnormal operating state occurs in the isolated grid.

[0011] As a preferred solution of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the optimization of the isolated grid system includes switching the frequency regulating units when the capacity of the isolated grid system changes.

[0012] As a preferred solution of the method for isolated grid operation and frequency control of multiple units in a hydropower station described in the present invention, the optimization of the isolated grid system also includes optimizing the isolated grid system by decoupling redundant units or shutting them down.

[0013] Another object of the present invention is to provide a hydropower station multi-unit isolated grid operation and frequency control system, which can enable the system to respond quickly when the frequency deviates through an automatic adjustment module, solving the current problem of lack of adaptive adjustment mechanism.

[0014] As a preferred solution for the multi-unit isolated grid operation and frequency control system of the hydropower station described in the present invention, it includes: a role allocation module, an automatic adjustment module, and an isolated grid optimization module; the role allocation module is used to determine the number of units to be incorporated into the isolated grid according to the total capacity of the isolated grid and allocate unit roles; the automatic adjustment module is used to adjust the unit frequency through a first strategy and transfer the load through a first method; the isolated grid optimization module is used to optimize the isolated grid system based on the isolated grid parameters.

[0015] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that the processor executes the computer program to implement the steps of a method for isolated grid operation and frequency control of multiple units in a hydropower station.

[0016] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of a method for isolated grid operation and frequency control of multiple units in a hydropower station.

[0017] Beneficial effects of the present invention: The multi-unit isolated grid operation and frequency control method of a hydropower station provided by the present invention ensures that each frequency-modulating unit has a slight parameter difference when adjusting the frequency by setting a graded frequency dead zone on the speed regulator of the frequency-modulating unit, thereby improving the operating stability of the system; by transferring the load between the frequency-modulating units and monitoring and avoiding the vibration zone, it is ensured that the system does not enter the frequency vibration zone or phase-modulating state during operation, thereby improving the anti-interference ability and stability of the system; the frequency-modulating units are increased or decreased in real time according to the load changes, so as to achieve a dynamic balance of power and frequency in the system, and ensure the frequency and load stability in the isolated grid operation; by setting the adjustment rate and frequency dead zone of the unit to 0, it is ensured that the system can still maintain frequency stability at low load, thereby improving the economy and operating efficiency of the isolated grid system; the present invention achieves better results in terms of stability, economy and operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0019] Figure 1 The present invention provides an overall flow chart of a method for isolated grid operation and frequency control of multiple units in a hydropower station according to the first and second embodiments of the present invention.

[0020] Figure 2A diagram of the coordination relationship between a multi-unit isolated grid load monitoring system and a speed regulator of a hydropower plant provided in accordance with a multi-unit isolated grid operation and frequency control method of the first and second embodiments of the present invention.

[0021] Figure 3 A schematic diagram of frequency dead zone switching in an isolated grid mode of a speed regulator of a hydropower station multi-unit isolated grid operation and frequency control method provided in the first and second embodiments of the present invention.

[0022] Figure 4 An isolated grid regulation structure diagram of a hydropower station multi-unit isolated grid operation and frequency control method provided for the first and second embodiments of the present invention.

[0023] Figure 5 An overall module diagram of a multi-unit isolated grid operation and frequency control system for a hydropower station provided in accordance with the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0024] 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.

[0025] Example 1

[0026] Reference Figure 1-Figure 4 , which is an embodiment of the present invention, provides a method for isolated grid operation and frequency control of multiple units in a hydropower station, comprising:

[0027] S1: Determine the number of units to be incorporated into the isolated grid based on the total capacity of the isolated grid and assign the roles of the units.

[0028] Furthermore, determining the number of units to be connected to the isolated grid according to the total capacity of the isolated grid includes determining the number of units to be connected to the isolated grid according to the total capacity of the isolated grid and adjusting the power of the units.

[0029] It should be noted that the total capacity of the units to be put into the isolated grid system must be greater than the estimated total load of the isolated grid. According to the total capacity of the isolated grid, the number of units to be incorporated into the isolated grid is determined. 60%-80% of the total unit capacity is the total load of the isolated grid system. The unit's main electrical connections are transferred to the isolated grid system. The unit's speed governor is in the isolated grid mode. The isolated grid parameters are retrieved, including PID, adjustment rate and frequency dead zone. The speed governor is in the isolated grid mode, which is characterized by the control target being the given frequency. The main control task of the speed governor is to detect the deviation between the grid frequency and 50Hz, and input the deviation into the PID unit for calculation and output to complete the unit power adjustment. By adjusting the power of each machine's speed governor, the power imbalance in the system is eliminated and the system frequency is consistent with 50Hz.

[0030] Furthermore, allocating the roles of the units includes comparing the total capacity of the partial isolated network with the capacity of the individual units to allocate the roles of the units.

[0031] It should be noted that if the unit capacity of the unit is 80% ≥ 10% of the total load capacity, that is, one unit is in frequency regulation mode, when i is the minimum, it is expressed as:

[0032]

[0033] Among them, P i is the capacity of a single unit, P f For the estimated total load power, if the capacity of a single machine is 80% < 10% of the total capacity, calculate whether the capacity of the two machines is met. If 80% of the total capacity of the two machines is ≥10%, that is, let the two machines be in frequency regulation mode. The two machines do not meet the requirement. If 80% of the total capacity of the three machines is ≥10%, that is, let the three machines be in frequency regulation mode. If there are more than 3 units, it means that the selected single machine capacity is too small. This selection method should be stopped and a unit with a larger single machine capacity should be reselected.

[0034] Example 2

[0035] Reference Figure 1-Figure 4 , which is an embodiment of the present invention, provides a method for isolated grid operation and frequency control of multiple units in a hydropower station, comprising:

[0036] S2: Adjust the unit frequency through the first strategy and transfer the load through the first method.

[0037] Furthermore, regulating the unit frequency through the first strategy includes stabilizing the frequency fluctuation of the isolated grid system by limiting the integral output and the change rate of the frequency deviation.

[0038] In the embodiment of the present application, the first strategy is the frequency deviation adjustment limiting strategy. If the unit assumes the role of frequency regulation, the speed regulator should be in the frequency regulation mode. When the speed regulator is in the frequency regulation mode, the frequency dead zone automatically switches to the small dead zone 1, which is generally 0.1Hz. If it is in the base load mode, its frequency dead zone automatically switches to the large dead zone 2, which is generally 0.5Hz.

[0039] After the speed governor enters the isolated grid, in the early stage of the large grid transitioning to the isolated grid, the speed governor clears the opening setting, and under the two effects of frequency PID and opening clearing, the guide vanes are quickly closed to suppress the increase in unit speed;

[0040] The frequency PID of the whole process always participates in the regulation with 50Hz as the target. Under the isolated grid, the power regulation intervention of the speed regulator lockout monitoring;

[0041] After switching to the isolated network, the PID parameters, bp, frequency dead zone and opening limit are automatically switched to the parameters set in the isolated network;

[0042] In order to prevent excessive integral calculations during large frequency difference adjustment, when the frequency overshoot requires secondary callback, excessive reverse integral will cause the problem of slow adjustment. The integral output size in the PID unit is limited. When the power load segment of a single machine is 0%-20%Pe, the DB limit range is ±10%, when the power load segment of a single machine is 20%-40%Pe, the DB limit range is ±15%, when the power load segment of a single machine is 40%-60%Pe, the DB limit range is ±20%, when the power load segment of a single machine is 60%-80%Pe, the DB limit range is ±25%, when the power load segment of a single machine is 80%-100%Pe, the DB limit range is ±30%. While limiting the size, it is also necessary to ensure the margin of full power adjustment of the unit. The calculated cumulative value Y of the input frequency difference of the integral link i Do a partial value transfer, that is, transfer it to a new variable and define the new variable as Y M , when the frequency difference is less than the dead zone, the current Y i Assign to Y M , Y i Reassign the value to 0 and set Y i Restricted to DB range;

[0043] In the PID total output link, a speed limit is set to limit the slope of the change, slow down the output speed in large fluctuation regulation, and prevent the system from causing chain adjustment and frequent adjustment of other units due to excessive power response of a single unit and excessive changes in system frequency.

[0044] In an optional embodiment, the first strategy may also be implemented in other ways, such as a multi-level integral control strategy, where different integral adjustment response levels are set for different frequency deviation amplitudes through multi-level integral control to achieve rapid suppression and stable control of frequency deviation;

[0045] When the system detects the frequency deviation of the isolated grid, it automatically triggers different levels of integral control parameters according to the deviation size. For small frequency deviation (less than 0.2Hz), the system only triggers the basic integral response to maintain the low rate of frequency change. For medium deviation (0.2-0.5Hz), the intermediate integral response is activated to adjust the frequency change rate. For large frequency deviation (greater than 0.5Hz), the system starts the advanced integral response to control the rapid return of the frequency through fast integral adjustment and amplitude limitation.

[0046] In order to prevent over-regulation in frequency regulation, integral limit and rate control are set at each response level. When the frequency difference is small, the integral amplitude is limited to ±5% to ensure the stability of frequency fluctuation. When the frequency difference is medium, the limit is adjusted to ±10%, and when the frequency difference is large, it is limited to ±20%. The limit setting under the advanced response ensures that the system can operate stably even when the frequency difference is large, avoiding frequency oscillation caused by excessive response of frequency regulation.

[0047] The frequency dead zone in the strategy will be dynamically adjusted according to the amplitude of the frequency deviation. When the system enters a small frequency difference range, the frequency dead zone of the frequency regulating unit will be automatically reduced to 0.05Hz to finely control the frequency. When the frequency difference is large, the dead zone will be widened to above 0.1Hz to ensure that the system can quickly restore the frequency target.

[0048] Furthermore, transferring the load by the first method includes transferring the load by the first method when an abnormal operating state occurs in the isolated grid.

[0049] In the embodiment of the present application, the first method is an isolated grid automatic load distribution and frequency modulation method. The frequency regulation and active power balance of the entire isolated grid system are automatically completed by the speed governor. Since multiple machines are loaded, there is no information exchange between the speed governors of the units. Some speed governors may be in a phase adjustment state, or the units may be operating in a vibration zone. However, the turbine is not allowed to operate under these two working conditions for a long time. The control system overcomes the abnormal state through the isolated grid automatic load distribution and frequency modulation method.

[0050] Assuming that the No. 1 frequency regulating unit is in the vibration zone and the No. 2 unit is carrying the base load, in the computer monitoring system in the central control room, one person single-handedly and single-step issues a load increase command to the speed governor of No. 1 unit, and another person single-handedly and single-step issues a load reduction command to the speed governor of No. 2 unit, until the No. 1 unit leaves the vibration zone and the No. 2 unit is also out of the vibration zone, and the load is transferred synchronously, slowly and equally, which can ensure that there is no large fluctuation in frequency and can also save the abnormal unit.

[0051] In an optional embodiment, the first method may also be implemented in other ways, such as an adaptive load priority transfer method, which intelligently selects the optimal load transfer path according to the load demand and unit status monitored in real time by the system to reduce frequency fluctuations and improve the response speed of the system;

[0052] The system is equipped with a real-time monitoring unit for the load, frequency fluctuation and abnormal operation status of all units in the isolated grid. When the load of the isolated grid changes abnormally, or a unit is overloaded, phase-shifted or operates in a vibration zone, the monitoring unit will give priority to recording the load information of the abnormal unit and mark it as an object to be processed.

[0053] Under abnormal conditions, the adaptive load priority transfer method prioritizes the transfer of overloaded or over-frequency units according to load demand. When the system load increases and there is a trend of frequency overshoot, the frequency-regulating units are given priority to perform the "load reduction" operation, and the excess load is distributed to the base load units that are not overloaded, thereby alleviating the pressure on the frequency-regulating units. At the same time, for units that are in a phase-shifting state due to insufficient load, the "load increase" command is triggered first to restore their load from the phase-shifting state to the normal power generation state, thereby improving the stability of the entire system.

[0054] The adaptive load priority transfer method optimizes the calculation of the load transfer path through an algorithm to ensure that each load transfer does not cause excessive frequency fluctuations. The system calculates the minimum load transfer amount and transfer path based on the current frequency deviation and the load conditions of each unit to avoid frequency oscillations caused by uneven or excessive load transfer. The system also supports gradual load transfer, that is, allocating larger loads into multiple steps to avoid drastic frequency fluctuations caused by a one-time transfer.

[0055] S3: Optimize the isolated grid system based on the isolated grid parameters.

[0056] Furthermore, the optimization of the isolated grid system includes switching the frequency regulating units when the capacity of the isolated grid system changes.

[0057] It should be noted that if the capacity of the isolated grid system changes and the active power of the frequency-modulating unit gradually exceeds 90% of the rated load, the second unit will be put into frequency modulation mode. When the second unit is ready to be put into use, the monitoring system sends a frequency modulation order to Unit 2. At this time, the frequency dead zone of Unit 2 is switched to 0.1Hz, and the monitoring system sends a frequency dead zone increase order to Unit 1, making the dead zone greater than 0.1Hz and greater than the dead zone of Unit 2, thus completing the role conversion.

[0058] Furthermore, optimizing the isolated grid system also includes optimizing the isolated grid system by decoupling redundant units or shutting them down.

[0059] It should be noted that if the frequency of the isolated grid system deviates greatly from the rated value in steady state, the operator will monitor the system on the computer in the central control room and issue a frequency dead zone reduction command to the unit No. 1 in the frequency regulation function. The gradient of each step of the speed governor is 0.01Hz / step. After each issuance, the frequency is observed, and then issued again and observed again until the requirements are met.

[0060] If the load of the isolated grid system is less than 30% of the capacity of one unit and other units are not needed for grid operation, the remaining units will be de-energized or shut down, leaving one unit to generate electricity. The speed regulator differential rate of the remaining unit will be set to 0, and the frequency dead zone will be reduced to 0.

[0061] Example 3

[0062] An embodiment of the present invention provides a method for isolated grid operation and frequency control of multiple units in a hydropower station. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0063] A simulated isolated grid system consisting of four hydropower station units was established. The total load of the simulated isolated grid was estimated to be 30MW. The system operated at a frequency of 50Hz. Two of the units were frequency-modulating units and the other two were base-load units. This experiment adjusted the frequency dead zone and load transfer operation of the frequency-modulating units to test the frequency response effect and stability of the system under different load changes and system interferences.

[0064] Based on the set value of the total load of the isolated grid, two of the four units are set as frequency-regulating units (units 1 and 2) for real-time frequency regulation, and the other two units (units 3 and 4) are used as base load units to maintain stable output to support the system load. The frequency dead zone of the frequency-regulating units is set to 0.1Hz and 0.2Hz, which are suitable for conditions with large and small load changes respectively. The base load units maintain constant output to enhance system inertia and reduce frequency fluctuations.

[0065] A PID automatic adjustment program is set for the frequency modulation unit, and the frequency target is 50Hz. When the load in the system suddenly increases by 10MW, the frequency modulation unit responds immediately, and the PID adjustment unit transfers the load according to the frequency deviation to restore frequency stability. The "increase load" command is executed on unit 1 to gradually increase the output power until the system frequency recovers to 50Hz. In addition, the system simulates frequency interference within 30 minutes, observes the frequency fluctuation range and response time, and dynamically adjusts the frequency dead zone of the frequency modulation unit by automatically monitoring the frequency and load fluctuation amplitude to optimize the accuracy of load transfer. Assume that after the system has been operating normally for 10 minutes, the load suddenly decreases by 5MW. At this time, the system automatically reduces the frequency dead zone of unit 1 from 0.1Hz to 0.05Hz to further improve the adjustment accuracy and reduce the frequency deviation, and records the frequency deviation changes of the system under different load conditions.

[0066] As shown in Table 1, when the system load increases by 10MW, the frequency modulation unit responds quickly, the frequency only drops to 49.85Hz, and recovers to 50Hz through load transfer within 15 seconds, which shows that the present invention has efficient frequency recovery capability. In the case of similar load mutation, the conventional system usually has large frequency fluctuation and longer recovery time. The present invention greatly reduces the frequency deviation and shortens the recovery time through reasonable frequency dead zone setting and PID adjustment strategy. When the load decreases by 5MW, the frequency dead zone of the frequency modulation unit is automatically reduced to 0.05Hz, which improves the adjustment accuracy and controls the frequency deviation within ±0. .1Hz, ensuring that the system frequency fluctuation amplitude is extremely small when the load is reduced, thereby avoiding system instability caused by rapid frequency fluctuations. Compared with the adjustment method in the traditional isolated network mode, it is more accurate and stable, and fully reflects the adaptive optimization ability of the present invention under complex load conditions. The data of the continuous interference test show that the frequency modulation unit can dynamically adjust the frequency under a small frequency difference, and the frequency recovery time is controlled within 3 seconds, indicating that the system of the present invention has excellent stability when dealing with external disturbances. The traditional isolated network control system often requires manual operation for frequency adjustment after interference, and the adjustment accuracy and response speed are not as good as the automatic control mode of the present invention.

[0067] Table 1 Experimental data table

[0068]

[0069] Example 4

[0070] Reference Figure 5 , which is an embodiment of the present invention, provides a hydropower station multi-unit isolated network operation and frequency control system, including: a role allocation module, an automatic adjustment module, and an isolated network optimization module.

[0071] The role allocation module is used to determine the number of units to be incorporated into the isolated network according to the total capacity of the isolated network and allocate the roles of the units; the automatic adjustment module is used to adjust the unit frequency through the first strategy and transfer the load through the first method; the isolated network optimization module is used to optimize the isolated network system based on the isolated network parameters.

[0072] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it 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, server, or network device, etc.) to perform all or part of the steps of the methods of 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. Various media that can store program codes.

[0073] 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.

[0074] 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 processing in another suitable manner as necessary, and then stored in a computer memory.

[0075] 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, multiple 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. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0076] 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 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 method for isolated grid operation and frequency control of multiple units in a hydropower station, characterized in that: include: Determine the number of units to be incorporated into the isolated grid based on the total capacity of the isolated grid and assign the roles of the units; adjusting the unit frequency by a first strategy and transferring the load by a first method; Based on the isolated grid parameters, the isolated grid system is optimized.

2. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 1, characterized in that: Determining the number of units to be incorporated into the isolated grid according to the total capacity of the isolated grid includes determining the number of units to be incorporated into the isolated grid according to the total capacity of the isolated grid, and adjusting the power of the units.

3. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 2, characterized in that: The allocation of unit roles includes comparing the total capacity of part of the isolated network with the capacity of a single unit of the unit, and allocating the unit roles.

4. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 3, characterized in that: The regulating of the unit frequency by the first strategy includes stabilizing the frequency fluctuation of the isolated grid system by limiting the integral output and the change rate of the frequency deviation.

5. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 4, characterized in that: The transferring of load by the first method includes transferring the load by the first method when an abnormal operating state occurs in an isolated grid.

6. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 5, characterized in that: The optimization of the isolated grid system includes switching the frequency regulating units when the capacity of the isolated grid system changes.

7. The method for isolated grid operation and frequency control of multiple units in a hydropower station according to claim 6, characterized in that: The optimization of the isolated grid system also includes optimizing the isolated grid system by decoupling redundant units or shutting them down.

8. A system using the method for isolated grid operation and frequency control of multiple units in a hydropower station as claimed in any one of claims 1 to 7, characterized in that: Including role allocation module, automatic adjustment module, and isolated network optimization module; The role allocation module is used to determine the number of units to be incorporated into the isolated network according to the total capacity of the isolated network and allocate the roles of the units; The automatic adjustment module is used to adjust the unit frequency through a first strategy and transfer the load through a first method; The isolated network optimization module is used to optimize the isolated network system based on the isolated network parameters.

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 for isolated grid operation and frequency control of multiple units in a hydropower station described in 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 for isolated grid operation and frequency control of multiple units in a hydropower station described in any one of claims 1 to 7 are implemented.

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