Multi-mode dynamic control method and system for offshore platform gas turbine generator set

Abstract

The invention relates to a multi-mode dynamic control method and system for an offshore platform gas turbine generator set. The method comprises the following steps: in a generator set grid-connected operation mode, based on a power closed-loop control mode, according to an external power set value, collecting active power and rotating speed signals of a generator set, and adjusting the fuel flow of a gas generator in real time, so that the rotating speed of a power turbine is synchronous with the frequency of a large power grid; under an offshore platform isolated network multi-generator network operation mode, based on a rotating speed droop control mode, load distribution is adjusted through the rotating speed of each generator set, and the stability of the platform frequency is maintained; under the offshore platform isolated network single-machine operation mode, based on the rotating speed indifference control mode, the rotating speed of a power turbine of a single generator set is kept constant; stable switching control among the operation modes is provided, and undisturbed switching is achieved. According to the invention, the problem of multi-mode control of the offshore platform in different power consumption scenes and the problem of reducing power consumption disturbance in the switching process in different scenes can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore platform gas turbine control, and in particular to a multi-mode dynamic control method and system for an offshore platform gas turbine generator set. Background Art

[0002] Offshore platforms are important operating terminals for offshore oil production. Offshore platforms are generally far away from the mainland. Associated gas (gas) is produced during offshore oil production. Several offshore platforms are built near an oil and gas field for joint production and equipped with multiple gas turbine generator sets for power generation. The stability of the platform's power supply directly affects whether the platform can carry out normal production activities.

[0003] Since shore power is connected to the land power grid and has high stability, in order to ensure that the platform can still produce normally after the failure of the platform's own generator set, shore power will be introduced into the platform's power supply system. However, this process will increase the electricity consumption during the production process of the offshore platform.

[0004] During the mining process, offshore platforms will generate a large amount of associated gas, which can be used as fuel for gas turbine generator sets to generate electricity. This power generation process not only reduces the platform's electricity expenditure on purchasing shore power, but also complies with national environmental protection and energy utilization policies due to the full use of associated gas and no direct emissions, which provides additional incentives for CNOOC. Therefore, under normal circumstances, the platform's electricity is mostly supplied by the platform's self-equipped generator sets.

[0005] When the platform generator set is used for power generation without shore power, there are two scenarios: multiple units generating electricity at the same time and a single unit generating electricity alone. When multiple units generate electricity at the same time, the balance of power distribution between units must be met; when a single gas turbine generator set is in operation, the stability of the platform's power frequency must be guaranteed (that is, when the power load fluctuates, the power turbine speed must be stable).

[0006] To ensure the stability of the platform's power consumption, the control system needs to perform smooth switching control when the above-mentioned power consumption scenarios change to reduce disturbances to the platform's power load. Summary of the invention

[0007] To this end, the present invention provides a multi-modal dynamic control method and system for an offshore platform gas turbine generator set, which can solve the multi-modal control problem under different power consumption scenarios of the offshore platform and the problem of reducing power disturbances during the switching process under different scenarios. On the basis of meeting various modal controls, through relevant state detection, the switching enable is automatically or manually triggered to meet the switching control.

[0008] In order to solve the above technical problems, the present invention provides a multi-mode dynamic control method for an offshore platform gas turbine generator set, comprising: In the grid-connected operation mode of the generator set, based on the power closed-loop control mode, according to the external power setting value, by collecting the active power and speed signals of the generator set, the fuel flow of the gas generator is adjusted in real time, so that the speed of the power turbine is synchronized with the grid frequency, thereby maintaining the output power stability; the grid-connected operation mode of the generator set is configured such that the power turbine is connected to the generator set through the gear box, and the stator AC of the generator set is connected to the grid AC; In the offshore platform isolated grid multi-machine network operation mode, based on the speed droop control mode, the load is distributed by adjusting the speed of each generator set to maintain the stability of the platform frequency; the offshore platform isolated grid multi-machine network operation mode is configured to disconnect the offshore platform from the shore power system, and multiple generator sets share the platform load; In the isolated grid single-machine operation mode of the offshore platform, the speed of the power turbine of the single generator set is maintained constant based on the speed difference control mode; the isolated grid single-machine operation mode of the offshore platform is configured that the offshore platform is not connected to the shore power system, and only one gas turbine generator set is in operation; Provide smooth switching control between various operating modes to achieve disturbance-free switching.

[0009] In one embodiment of the present invention, the smooth switching control includes: In the power closed-loop control mode, the control system preselects a load value that follows the active power acquisition value of the generator set; When the power closed-loop control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load of the speed droop control mode to achieve disturbance-free switching.

[0010] In one embodiment of the present invention, the smooth switching control further includes: In the speed droop control mode, the active power setpoint of the generator set follows the preselected load setpoint; When the speed droop control mode is switched to the power closed-loop control mode, the preselected load at the switching moment is used as the set value of the generator active power to achieve a power closed-loop.

[0011] In one embodiment of the present invention, the smooth switching control further includes: In the speed differenceless control mode, the control system preselects a load value to follow the generator active power acquisition value; When the speed zero-difference control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load in the speed droop control mode to achieve disturbance-free switching.

[0012] In one embodiment of the present invention, the smooth switching control further includes: When the speed droop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

[0013] In one embodiment of the present invention, the smooth switching control further includes: When the power closed-loop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

[0014] In one embodiment of the present invention, the smooth switching control further includes: In the speed difference-free control mode, the generator active power set value follows the generator active power acquisition value; When the speed differenceless control mode is switched to the power closed-loop control mode, the active power acquisition value of the generator set at the switching moment is used as the set value of the active power of the generator set to realize the power closed-loop.

[0015] In one embodiment of the present invention, it also includes: According to the system frequency, a given turbine speed of the power turbine is set, wherein in the offshore platform isolated network multi-machine network operation mode, the given turbine speed is dynamically allocated according to the droop characteristic curve of the unit; in the offshore platform isolated network single machine operation mode, the given turbine speed is a fixed value; Obtaining feedback turbine speed of the power turbine; Calculating a speed deviation value according to the given turbine speed and the feedback turbine speed; The PI controller generates a speed regulation signal according to the speed deviation value; Convert the speed regulation signal into a valve opening signal to control the fuel flow of the gas generator; A speed feedback signal is obtained, and according to the speed regulation signal and the speed feedback signal, an adjustment range of the speed regulation signal is made within a limiting loop.

[0016] In one embodiment of the present invention, it also includes: According to the shore power load demand, set the given power of the generator set; Obtain feedback power from the generator set; Calculating a power deviation value according to the given power and the feedback power; The PI controller generates a power regulation signal according to the power deviation value; Convert the power regulation signal into a valve opening signal for controlling the fuel flow of the gas generator; A power feedback signal is obtained, and an adjustment range of the power adjustment signal is made within a limiting loop according to the power adjustment signal and the power feedback signal.

[0017] The present invention also provides a multi-mode dynamic control system for an offshore platform gas turbine generator set, comprising: A power closed-loop control unit is used to adjust the fuel flow of the gas generator in real time in the power closed-loop control mode according to the external power setting value by collecting the active power and speed signals of the generator set in the power grid-connected operation mode, so as to synchronize the power turbine speed with the grid frequency, thereby maintaining the output power stability; the power grid-connected operation mode of the generator set is configured such that the power turbine is connected to the generator set through a gear box, and the stator AC of the generator set is connected to the grid AC; A speed droop control unit is used to distribute the load by adjusting the speed of each generator set to maintain the stability of the platform frequency in an offshore platform isolated grid multi-machine network operation mode based on a speed droop control mode; the offshore platform isolated grid multi-machine network operation mode is configured so that the offshore platform is disconnected from the shore power system and the platform load is shared by multiple generator sets; A speed differential control unit, used to maintain a constant speed of a power turbine of a single generator set based on a speed differential control mode in an isolated grid single machine operation mode of an offshore platform; the isolated grid single machine operation mode of the offshore platform is configured such that the offshore platform is not connected to the shore power system and only one gas turbine generator set is in operation; The disturbance-free switching unit is used to provide smooth switching control between various operating modes to achieve disturbance-free switching.

[0018] The above technical solution of the present invention has the following advantages compared with the prior art: The multi-mode dynamic control method and system of the offshore platform gas turbine generator set described in the present invention can complete the self-check of the unit before starting by configuring the large-grid mode control connected to shore power, the offshore platform isolated grid multi-machine networking mode control, the offshore platform single-machine power generation mode control, the high-speed current feedforward control in the single-machine mode, and the smooth switching control in multiple modes. According to the mode setting, the large-grid mode, the isolated grid mode or the single-machine mode is selected for normal starting. During operation, the control system performs real-time unit status detection. When an external abnormality is triggered or the operator manually triggers the mode switching, the unit's external output power is kept unchanged. By following the key parameters related to the previous mode, the calculation and distribution of the combustion calorific value, the smooth switching between different control modes is achieved.

[0019] The present invention satisfies the multi-modal control and online smooth switching functions of the gas turbine generator set on the offshore platform in different usage scenarios such as shore power grid connection, multi-machine isolated grid on the platform, and single-machine power generation, thereby stably ensuring the electricity demand for normal oil and gas production activities and personnel life on the offshore platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the multi-modal control and switching process of the present invention.

[0022] Figure 2 It is a schematic diagram of the control system architecture of the present invention.

[0023] Figure 3 It is a schematic diagram of the closed-loop control of the power turbine speed of the present invention.

[0024] Figure 4 It is a schematic diagram of power closed-loop control of the present invention.

[0025] Figure 5 It is the droop control adjustment characteristic curve of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0027] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0028] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0029] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0030] Example 2 Reference Figure 1 As shown, this embodiment provides a multi-mode dynamic control method for an offshore platform gas turbine generator set, comprising: In the grid-connected operation mode of the generator set, based on the power closed-loop control mode, according to the external power setting value, by collecting the active power and speed signals of the generator set, the fuel flow of the gas generator is adjusted in real time, so that the speed of the power turbine is synchronized with the grid frequency, thereby maintaining the output power stability; the grid-connected operation mode of the generator set is configured such that the power turbine is connected to the generator set through the gear box, and the stator AC of the generator set is connected to the grid AC; In the offshore platform isolated grid multi-machine network operation mode, based on the speed droop control mode, the load is distributed through the speed adjustment of each generator set to maintain the stability of the platform frequency; the offshore platform isolated grid multi-machine network operation mode is configured to disconnect the offshore platform from the shore power system, and multiple generator sets share the platform load; in this operation mode, since it is not interconnected with the large grid, the platform isolated grid frequency is guaranteed by the platform generator set, that is, speed closed-loop control is required; due to the different characteristics of gas turbine generators from different manufacturers and different series, the current unit cannot be set to fixed frequency (50Hz) control. Combined with the EMS (Energy Management System) system dispatch, the gas turbine generator set uses speed droop control; In the isolated grid single-machine operation mode of the offshore platform, the speed of the power turbine of a single generator set is maintained constant based on the speed difference-free control mode; the isolated grid single-machine operation mode of the offshore platform is configured such that the offshore platform is not connected to the shore power system, and only one gas turbine generator set is in operation; in this operation mode, in order to cope with the sudden increase or decrease of the external power load, high-speed current feedforward control is introduced; through high-speed current signal acquisition and corresponding relationship, compensation feedforward is introduced on the basis of the normal Np closed loop; Provide smooth switching control between various operating modes to achieve disturbance-free switching. When the control system switches between different modes, it collects key parameters of the mode before switching (such as power and speed) in real time and uses them as reference values ​​for subsequent modes. During the switching process, the control system follows the calculation and parameter calibration to avoid load fluctuations.

[0031] Before switching, key parameters (such as active power and speed) in the current mode are collected; when switching, the parameters at the switching moment are used as the input reference for the subsequent mode; disturbance-free switching between different modes is achieved to reduce load fluctuations. It adapts to various power supply modes of offshore platforms and improves the applicability of control system operation; through smooth switching control, load disturbances are significantly reduced during switching; high-speed current feedforward compensation in single-machine mode improves the dynamic response speed to load mutations.

[0032] Figure 1 The three operating modes and switching relationships of offshore platform gas turbine generator sets are shown: Mode 1 (interconnection with shore power, power closed-loop control): This mode ensures that the generator set operates synchronously with the grid frequency.

[0033] Mode 2 (isolated grid operation on offshore platform, multi-generator speed droop control): multiple units share the isolated grid load to maintain system frequency stability.

[0034] Mode 3 (single machine operation on offshore platform, zero speed control): The single machine is independently powered and the frequency is kept stable through zero speed control.

[0035] Switching process (marked by arrows): ①② Switching from large network mode to isolated network mode, or switching from isolated network back to large network mode; ③④ Switching between single machine and multiple machines in isolated network mode; ⑤⑥ Switching from single machine mode to large network mode, or switching from large network back to single machine mode.

[0036] Figure 2 This is a schematic diagram of the control system architecture. Specifically includes: Data acquisition module: including medium voltage electrical system, low voltage electrical system and DC electrical system. It is responsible for monitoring and collecting important parameters (such as voltage, current, power, etc.) in each electrical system and providing them to the electronic control cabinet through analog and discrete signals.

[0037] Generator and gearbox: The generator and gearbox form the core part of the power generation. The gearbox connects the turbine and generator by adjusting the speed ratio.

[0038] Auxiliary system: Provides auxiliary support for the operation of gas turbines and generator sets, including lubrication, cooling and gas transportation.

[0039] Electronic control cabinet: It is the core control unit of the entire system, responsible for processing data from each module and sending instructions to adjust the operating status of each device according to the control algorithm. It contains the following sub-modules: CNC A channel and CNC B channel are the main control modules and adopt dual-channel redundant design (A channel and B channel) to ensure high reliability of the system.

[0040] Independent over-speed protection device: protects the power turbine of the gas turbine from exceeding the set safe speed during operation.

[0041] ESD protection device: Emergency Shut Down (ESD), which stops the turbine operation in an emergency when a major fault occurs in the system.

[0042] Fuel and pilot control system: regulates the fuel supply and air flow of the gas turbine to ensure efficient and safe operation of the turbine.

[0043] Engine (including sensors): The engine is the core power unit of the gas turbine, and its operating status is monitored in real time through a variety of sensors.

[0044] Sensor signal: Pbc, Phg, Phy: pressure sensor signals, used to monitor the pressure of gas flow; Vc, Vt: speed sensor signals, monitoring the speed of the power turbine and generator; Toil, Toh: Temperature sensor signal, used to monitor the temperature of lubricating oil or gas; T6z, T6g, T6h: exhaust temperature sensor signal, monitoring the temperature distribution of turbine exhaust; Np: Turbine speed signal, which is the core parameter of speed closed-loop control.

[0045] Ignition device: responsible for igniting the gas and starting the working cycle of the gas turbine; Starting device: Provides mechanical energy when the gas turbine is first running to accelerate the turbine to the starting speed.

[0046] Sound and light alarm: Send out warning signals in case of fault or abnormal conditions.

[0047] Each module collects the operating status of the equipment through sensors and transmits analog and discrete signals to the electronic control cabinet. The electronic control cabinet executes the control algorithm through the CNC channel and ensures the safety of the system through protection devices (such as over-speed protection and ESD devices). The fuel regulation system, ignition device, etc. adjust the operating status according to the control signal and return the feedback signal to the control cabinet to form a closed loop. The system realizes remote monitoring through the monitoring computer, realizes manual operation through indicator lights and buttons, and provides abnormal prompts through sound and light alarms.

[0048] Specifically, the smooth switching control includes: In the power closed-loop control mode, the control system preselects a load value that follows the active power acquisition value of the generator set; When the power closed-loop control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load of the speed droop control mode to achieve disturbance-free switching.

[0049] Specifically, the smooth switching control includes: In the speed droop control mode, the active power setpoint of the generator set follows the preselected load setpoint; When the speed droop control mode is switched to the power closed-loop control mode, the preselected load at the switching moment is used as the set value of the generator active power to achieve a power closed-loop.

[0050] In the speed differenceless control mode, the control system preselects a load value to follow the generator active power acquisition value; When the speed zero-difference control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load in the speed droop control mode to achieve disturbance-free switching.

[0051] When the speed droop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

[0052] When the power closed-loop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

[0053] In the speed difference-free control mode, the generator active power set value follows the generator active power acquisition value; When the speed differenceless control mode is switched to the power closed-loop control mode, the active power acquisition value of the generator set at the switching moment is used as the set value of the active power of the generator set to realize the power closed-loop.

[0054] Figure 3 The schematic diagram of the closed-loop control of the power turbine speed is shown in Figure 1. According to the system frequency, the given turbine speed of the power turbine is set, wherein in the offshore platform isolated network multi-machine network operation mode, the given turbine speed is dynamically allocated according to the droop characteristic curve of the unit; in the offshore platform isolated network single machine operation mode, the given turbine speed is a fixed value; Obtaining feedback turbine speed of the power turbine; Calculating a speed deviation value ΔNp according to the given turbine speed and the feedback turbine speed; The PI controller generates a speed regulation signal according to the speed deviation value; Convert the speed regulation signal into a valve opening signal ΔNgr, which is used to control the fuel flow of the gas generator; A speed feedback signal is obtained, and according to the speed regulation signal and the speed feedback signal, an adjustment range of the speed regulation signal is made within a limiting loop.

[0055] Figure 4 It is a schematic diagram of power closed-loop control. Specifically, it also includes: According to the shore power load demand, set the given power of the generator set; Obtain feedback power from the generator set; Calculating a power deviation value according to the given power and the feedback power; The PI controller generates a power regulation signal according to the power deviation value; Convert the power regulation signal into a valve opening signal for controlling the fuel flow of the gas generator; A power feedback signal is obtained, and an adjustment range of the power adjustment signal is made within a limiting loop according to the power adjustment signal and the power feedback signal.

[0056] Figure 5 This is the droop control adjustment characteristic curve. This figure shows the speed droop characteristics in the isolated multi-machine mode. The horizontal axis represents the percentage of active power of the generator; the vertical axis represents the frequency (Hz).

[0057] It can be seen that the speed drops as the load increases, maintaining the dynamic balance of the system frequency; under different loads, the frequency adjustment range is 48Hz (96%) to 52Hz (104%). By adjusting the unit regulation amount (SP), the load balance of the isolated grid is maintained.

[0058] Example 2 Based on the same inventive concept, this embodiment provides a multi-modal dynamic control system for an offshore platform gas turbine generator set. The principle of solving the problem is similar to the method of multi-modal dynamic control of the offshore platform gas turbine generator set, and the repeated parts are not repeated here.

[0059] This embodiment provides a multi-mode dynamic control system for an offshore platform gas turbine generator set, including: A power closed-loop control unit is used to adjust the fuel flow of the gas generator in real time in the power closed-loop control mode according to the external power setting value by collecting the active power and speed signals of the generator set in the power grid-connected operation mode, so as to synchronize the power turbine speed with the grid frequency, thereby maintaining the output power stability; the power grid-connected operation mode of the generator set is configured such that the power turbine is connected to the generator set through a gear box, and the stator AC of the generator set is connected to the grid AC; A speed droop control unit is used to distribute the load by adjusting the speed of each generator set to maintain the stability of the platform frequency in an offshore platform isolated grid multi-machine network operation mode based on a speed droop control mode; the offshore platform isolated grid multi-machine network operation mode is configured so that the offshore platform is disconnected from the shore power system and the platform load is shared by multiple generator sets; A speed differential control unit, used to maintain a constant speed of a power turbine of a single generator set based on a speed differential control mode in an isolated grid single machine operation mode of an offshore platform; the isolated grid single machine operation mode of the offshore platform is configured such that the offshore platform is not connected to the shore power system and only one gas turbine generator set is in operation; The disturbance-free switching unit is used to provide smooth switching control between various operating modes to achieve disturbance-free switching.

[0060] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0061] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0062] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0063] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0064] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand 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.

Claims

1. A multi-mode dynamic control method for an offshore platform gas turbine generator set, characterized in that: include: In the grid-connected operation mode of the generator set, based on the power closed-loop control mode, according to the external power setting value, by collecting the active power and speed signals of the generator set, the fuel flow of the gas generator is adjusted in real time to synchronize the power turbine speed with the grid frequency, thereby maintaining the output power stability; The generator set parallel to the grid operation mode is configured such that the power turbine is connected to the generator set through the gear box, and the stator AC power of the generator set is connected to the grid AC power; In the offshore platform isolated network multi-machine network operation mode, based on the speed droop control mode, the speed of each generator set is adjusted to distribute the load and maintain the stability of the platform frequency; The offshore platform isolated grid multi-machine network operation mode is configured so that the offshore platform is disconnected from the shore power system, and the platform load is shared by multiple generator sets; In the isolated grid single-machine operation mode of the offshore platform, the speed of the power turbine of a single generator set is maintained constant based on the speed difference control mode; The offshore platform isolated grid single machine operation mode is configured such that the offshore platform is not connected to the shore power system and only one gas turbine generator set is in operation; Provide smooth switching control between various operating modes to achieve disturbance-free switching.

2. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control includes: In the power closed-loop control mode, the control system preselects a load value that follows the active power acquisition value of the generator set; When the power closed-loop control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load of the speed droop control mode to achieve disturbance-free switching.

3. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control further comprises: In the speed droop control mode, the active power setpoint of the generator set follows the preselected load setpoint; When the speed droop control mode is switched to the power closed-loop control mode, the preselected load at the switching moment is used as the set value of the generator active power to achieve a power closed-loop.

4. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control further comprises: In the speed differenceless control mode, the control system preselects a load value to follow the generator active power acquisition value; When the speed zero-difference control mode is switched to the speed droop control mode, the active power at the switching moment is used as the preselected load in the speed droop control mode to achieve disturbance-free switching.

5. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control further comprises: When the speed droop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

6. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control further comprises: When the power closed-loop control mode is switched to the speed zero-difference control mode, the frequency of the generator set is controlled to be 50 Hz, that is, the power turbine is maintained at a constant speed.

7. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: The smooth switching control further comprises: In the speed difference-free control mode, the generator active power set value follows the generator active power acquisition value; When the speed differenceless control mode is switched to the power closed-loop control mode, the active power acquisition value of the generator set at the switching moment is used as the set value of the active power of the generator set to realize the power closed-loop.

8. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: Also includes: According to the system frequency, a given turbine speed of the power turbine is set, wherein in the offshore platform isolated network multi-machine network operation mode, the given turbine speed is dynamically allocated according to the droop characteristic curve of the unit; in the offshore platform isolated network single machine operation mode, the given turbine speed is a fixed value; Obtaining feedback turbine speed of the power turbine; Calculating a speed deviation value according to the given turbine speed and the feedback turbine speed; The PI controller generates a speed regulation signal according to the speed deviation value; Convert the speed regulation signal into a valve opening signal to control the fuel flow of the gas generator; A speed feedback signal is obtained, and according to the speed regulation signal and the speed feedback signal, an adjustment range of the speed regulation signal is made within a limiting loop.

9. The multi-mode dynamic control method for an offshore platform gas turbine generator set according to claim 1, characterized in that: Also includes: According to the shore power load demand, set the given power of the generator set; Obtain feedback power from the generator set; Calculating a power deviation value according to the given power and the feedback power; The PI controller generates a power regulation signal according to the power deviation value; Convert the power regulation signal into a valve opening signal for controlling the fuel flow of the gas generator; A power feedback signal is obtained, and an adjustment range of the power adjustment signal is made within a limiting loop according to the power adjustment signal and the power feedback signal.

10. A multi-mode dynamic control system for an offshore platform gas turbine generator set, characterized in that: include: The power closed-loop control unit is used to adjust the fuel flow of the gas generator in real time based on the power closed-loop control mode and the external power setting value by collecting the active power and speed signals of the generator set in the power grid-connected operation mode, so as to synchronize the power turbine speed with the grid frequency and maintain the output power stability; The generator set parallel to the grid operation mode is configured such that the power turbine is connected to the generator set through the gear box, and the stator AC power of the generator set is connected to the grid AC power; The speed droop control unit is used to distribute the load by adjusting the speed of each generator set to maintain the stability of the platform frequency based on the speed droop control mode in the offshore platform isolated network multi-machine network operation mode; The offshore platform isolated grid multi-machine network operation mode is configured so that the offshore platform is disconnected from the shore power system, and the platform load is shared by multiple generator sets; The speed differential control unit is used to maintain the power turbine speed of a single generator set constant based on the speed differential control mode in the isolated network single machine operation mode of the offshore platform; The offshore platform isolated grid single machine operation mode is configured such that the offshore platform is not connected to the shore power system and only one gas turbine generator set is in operation; The disturbance-free switching unit is used to provide smooth switching control between various operating modes to achieve disturbance-free switching.

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