Turbine dual-fuel switching control method with self-adaptive gas pressure threshold value

Abstract

The invention provides a turbine dual-fuel switching control method with a self-adaptive gas pressure threshold value, belongs to the technical field of turbine generator sets, and is applied to turbine sets with dual-fuel transformation completed. According to the method, an original manual oil transfer function is reserved, a near-point turbine inlet side and far-point gas buffer tank double-pressure acquisition unit is constructed, an oil transfer pressure threshold value is calculated in a self-adaptive mode based on an ideal gas state equation and a dynamic working condition correction model, a double-path triggering mechanism is configured, and when any path meets a triggering condition, the oil transfer pressure threshold value is calculated in a self-adaptive mode. And the turbine control system automatically executes a gas-to-fuel switching program. The problems that traditional manual oil transfer depends on manpower, response lags behind, fuel oil is wasted and the like are solved, the oil transfer time is smaller than or equal to 1 min, the power fluctuation is smaller than or equal to 300 kW, the stability, economical efficiency and anti-risk capacity of unit operation are remarkably improved, and the method is particularly suitable for ocean platforms and other scenes with the high requirement for power supply reliability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of turbine generator set, more particularly, it relates to a turbine dual-fuel switching control method with adaptive gas pressure threshold. BACKGROUND

[0002] The turbine generator set is the core power supply equipment in scenarios such as offshore platforms and natural gas power stations, and its operation stability directly affects the continuity of production operations. The turbine unit of a certain platform in Wenchang originally operated in a single gas mode, which had obvious defects: when the gas supply was insufficient, it was easy to trigger low pressure shutdown, leading to fluctuations in power supply and affecting oilfield production and drilling operations; and it could not start the unit by diesel during black start, with poor operation flexibility.

[0003] To improve this situation, the dual-fuel nozzle of the unit was modified in August 2025, and after the modification, manual switching function between gas and fuel oil was realized. The test showed that the oil transfer time was stably controlled within 1 minute, the unit power fluctuation was ≤300kW during mode switching, and the platform operation requirements were basically met. However, there are still key technical defects after the modification: the oil transfer operation completely depends on the real-time monitoring of the gas pressure by the operator, and the switching command is triggered by the manual button of the control cabinet, which not only has high labor intensity, but also has significant response lag and operation error risk; when the gas pressure drops suddenly, the delay of manual intervention can easily lead to fluctuations in unit load and even shutdown; at the same time, manual operation cannot accurately control the oil transfer timing, and too early oil transfer can cause frequent oil transfer, power grid fluctuations and fuel waste, and too late oil transfer can cause insufficient gas supply to the unit, further affecting the stability of power supply.

[0004] The manual oil transfer mode of the existing dual-fuel turbine unit cannot meet the high requirements of scenarios such as offshore platforms for power supply reliability and economy, and an automatic, accurate and fast fuel switching control method is urgently needed to make up for the shortcomings of manual operation and ensure the continuous and stable operation of the unit. SUMMARY

[0005] To solve the above technical problems, the present application provides a turbine dual-fuel switching control method with adaptive gas pressure threshold, which solves the technical problems of response lag, operation error, fuel waste, inaccurate oil transfer timing and affected power grid stability caused by the turbine unit after dual-fuel modification relying only on manual oil transfer, and meets the high requirements of scenarios such as offshore platforms for power supply reliability.

[0006] The turbine dual-fuel switching control method with adaptive gas pressure threshold is applied to a turbine unit that has completed dual-fuel modification, retains the original manual oil transfer function, and realizes automatic switching from gas to fuel oil through double-pressure acquisition, adaptive threshold calculation and double-path triggering, including the following steps:

[0007] S1: Constructing a double-pressure acquisition unit: setting a near-point pressure acquisition end and a far-point pressure acquisition end, the near-point pressure acquisition end acquires the pressure at the gas inlet side of the turbine unit, and the far-point pressure acquisition end acquires the pressure in the gas buffer tank, the two-point acquisition signals are mutually backed up;

[0008] S2: Building an adaptive threshold calculation module: real-time acquisition of unit operating condition parameters, dynamic calculation of near-point pressure threshold P1 and far-point pressure threshold P2 based on the ideal gas state equation and dynamic operating condition correction model, the operating condition parameters include gas buffer tank volume V, unit real-time gas consumption Q, near-point minimum stable operating pressure Pmin, oil switching time tswitch, and pipeline transmission loss ΔP between the near-point and the far-point;

[0009] S3: Configuring a double-path trigger module: the near-point pressure acquisition end outputs a trigger signal through a mechanical pressure switch, and the far-point pressure acquisition end outputs a trigger signal after delay filtering processing of the pressure sensing signal;

[0010] S4: Switching control: when any path in the double-path trigger module meets the trigger condition, the turbine control system receives the signal and executes the switching program from the gas mode to the oil mode according to the preset timing, and completes the automatic oil switching.

[0011] Preferably, in step S1:

[0012] The installation position of the near-point pressure acquisition end is between the gas shutoff valve outside the turbine box and the first-stage shutoff valve inside the box;

[0013] The installation position of the far-point pressure acquisition end is the turbine gas buffer tank, and the original pressure sensor connected to the central control PCS system is used for pressure acquisition.

[0014] Preferably, in step S1:

[0015] The near-point pressure acquisition end uses a mechanical pressure switch, and the mechanical pressure switch uses a normally closed contact to access the turbine control system;

[0016] The far-point pressure acquisition end uses a pressure transmitter to convert the acquired pressure signal into a 4-20mA AI signal and transmit it to the central control PCS system.

[0017] Preferably, the calculation process of the adaptive threshold calculation module in step S2 includes:

[0018] Based on the ideal gas state equation simplified model t=V×(P0-Pmin) / Q, the turbine operating time t is calculated to ensure that t≥tswitch;

[0019] The near-point theory optimal threshold P1opt is calculated by the formula P1opt=Pmin+(Q×tswitch) / V, and the dynamic threshold P1 is obtained after reserving a safety margin;

[0020] In combination with the pipeline transmission loss ΔP=P01-P02 (wherein P01 is the far-point normal operating pressure, and P02 is the near-point normal operating pressure), the far-point dynamic threshold P2=P1+ΔP is derived.

[0021] Preferably, the triggering logic of the near-point pressure acquisition end in step S3 is that when the near-point acquisition pressure ≤ the dynamic threshold P1, the mechanical pressure switch contact is closed, a DO signal is output to the turbine control system, and emergency oil turning is triggered.

[0022] Preferably, the triggering logic of the far-point pressure acquisition end in step S3 is that the central control PCS system performs delay filtering processing on the received AI signal, eliminates instantaneous pressure fluctuation interference, when the far-point acquisition pressure ≤ the dynamic threshold P2 and the duration ≥ 2s, a DO signal is output to the turbine control system, and predictive oil turning is triggered.

[0023] Preferably, the linkage mechanism of the double-path triggering module in step S4 is that the near-point triggering signal and the far-point triggering signal are independent of each other, when any signal is valid, the turbine control system immediately starts the oil turning program, and the two-path triggering signals do not conflict.

[0024] Preferably, the adjustment mechanism of the adaptive threshold calculation module in step S2 is that when the variation amplitude of the real-time operating condition parameters of the unit exceeds the preset threshold ±10%, the dynamic thresholds P1 and P2 are recalculated, and the real-time adaptive update of the thresholds is realized.

[0025] Preferably, the reserved manual oil turning function and the automatic oil turning function can be independently operated, a manual triggering signal is generated through a control cabinet button, is input into the turbine control system in parallel with the automatic triggering signal, and the two are switched without mechanical and logical conflicts.

[0026] Preferably, the execution standard of the oil turning program in step S4 is that the oil turning time ≤ 1min, and the unit power fluctuation ≤ 300kW, which is suitable for scenarios such as offshore platforms that have high requirements for power supply reliability.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The application triggers oil switching automatically when the gas pressure is abnormal without manual monitoring and intervention through the near-point mechanical pressure switch and the far-point pressure sensor double-path triggering mechanism. The near-point path has strong anti-interference ability and can quickly respond to pressure drop scenarios. The far-point path is processed by time delay filtering and can predict the pressure trend to switch oil in advance, effectively avoiding the problems of response lag, judgment error and switching delay of manual operation, and ensuring the timeliness and accuracy of fuel switching.

[0029] Based on the ideal gas state equation and the dynamic working condition correction model, the oil switching pressure threshold is adaptively calculated, which not only avoids frequent switching and excessive fuel consumption caused by early oil switching, but also prevents the unit fluctuation risk caused by late oil switching. By accurately controlling the oil switching time, the fuel consumption is maximally reduced under the premise of ensuring stable operation, and the unit operation cost is reduced.

[0030] The double-pressure acquisition units back up each other, and the double-path triggering mechanism is independently linked. When any path fails, the other path can still work normally. At the same time, the original manual oil switching function is retained, forming a "automatic + manual" double protection mode, which effectively deals with pressure fluctuations, equipment failures and other emergencies under complex working conditions of offshore platforms, avoids unit shutdown or power interruption, and ensures the continuous production of oil fields and drilling operations.

[0031] The application is based on the completed dual-fuel modification of the unit. The far-point pressure acquisition reuses the original pressure transmitter and the central control PCS system. Only the near-point mechanical pressure switch and the optimized control program need to be added, without the need to significantly modify the unit main machine and core pipeline. The application has good compatibility with the original system, short modification cycle, controllable cost, and is easy to popularize and apply.

[0032] The control method of the application can flexibly adjust parameters through the adaptive threshold calculation module according to different turbine unit gas buffer tank volumes, rated gas consumption, pressure operating range and other parameters. It is not only suitable for offshore turbine units, but also can be adapted to various scenes with high requirements for power supply reliability such as onshore natural gas power stations and industrial production turbine units, and has strong practicality. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a schematic diagram of the added program of the central control PCS in the application;

[0034] Figure 2 is a schematic diagram of the double-path oil switching logic linkage mechanism in the application;

[0035] Figure 3 is the gas-to-oil under the condition of 5500kW in the application;

[0036] Figure 4 is the gas-to-oil under the condition of 3000kW in the application;

[0037] Figure 5 is the gas cut oil under the condition of 1500 kW in the present application. DETAILED DESCRIPTION

[0038] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0039] Please refer to Figures 1-5 , the present application provides a turbine dual-fuel switching control method with adaptive gas pressure threshold. The present embodiment is based on a turbine unit that has completed dual-fuel modification on a certain offshore platform in Wenchang, ensuring that the implementation process is repeatable and verifiable.

[0040] Implementation prerequisites and equipment preparation:

[0041] 1. Unit basic conditions:

[0042] The turbine unit of the present embodiment has completed dual-fuel nozzle modification (modification time August 2025), has a gas / oil manual switching function, and the key parameters after modification are as follows:

[0043] Gas buffer tank volume V = 30 m³;

[0044] Far point gas buffer tank normal operating pressure P01 = 30 MPa;

[0045] Near point (between the turbine box outer gas shut-off valve and the box inner first-stage shut-off valve) normal operating pressure P02 = 24 MPa;

[0046] Near point turbine minimum stable operating pressure Pmin = 12 MPa;

[0047] Turbine unit rated gas consumption Q = 66.7 m³ / min (under standard conditions);

[0048] Manual oil transfer test verification: oil transfer time ≤ 1 min, power fluctuation ≤ 300 kW, meeting the platform operation basic requirements.

[0049] 2. Core equipment selection and adaptation:

[0050] Device name Model / specification Installation location Functional purpose Mechanical pressure switch PS3701 (normally closed contact) Near point (between the turbine casing outer gas shut-off valve and the casing inner first-stage shut-off valve) Collect near-point gas pressure and output DO trigger signal Pressure transmitter Original (already connected to central control PCS system) Far point (gas buffer tank) Collect far-point gas pressure and output 4-20 mA AI signal Turbine control system Original unit control system (compatible with DO signal input) In the unit control cabinet Receive oil transfer trigger signal and execute switching program Central control PCS system Original (support program expansion) Platform control room Process far-point pressure signal, implement delay filtering and threshold judgment Signal transmission cable Shielded DO signal line, 4-20 mA AI signal line Between pressure collection end and control system Ensure anti-interference transmission of pressure signal

[0051] Dual-pressure acquisition unit construction and installation and debugging:

[0052] 1. Near point pressure acquisition end installation:

[0053] Installation location: strictly according to the turbine gas flow PID drawing, select the pipeline position between the turbine box outer gas shut-off valve (XV3701) and the box inner first-stage shut-off valve (XV3702). This position directly reflects the turbine inlet gas pressure and has fast response speed;

[0054] Installation process: The mechanical pressure switch PS3701 is fixed with the gas pipeline through the flange interface (DN25-Class300, material 022Cr22Ni5Mo3N), ensuring that the sealing performance meets the 3.5MPa pressure level requirement, and the pressure sensing element is in close contact with the inner wall of the pipeline without pressure transmission delay;

[0055] Wiring configuration: The normally closed contact is connected to the turbine control system, the power line is 24VDC, the signal line is shielded DO line, the wiring terminal is fastened and insulated to avoid corrosion and interference in the marine environment.

[0056] 2. Far point pressure acquisition end adaptation:

[0057] Device reuse: The original pressure transmitter of the gas buffer tank (PIT4003) is connected to the central control PCS system, without the need for additional hardware devices, and signal reuse is achieved only by program expansion of the central control PCS system;

[0058] Signal verification: Check the signal transmission state of the pressure transmitter to ensure that the output 4-20mA AI signal linearity error is ≤±0.5%, and it is stable under 30MPa rated pressure without drift phenomenon;

[0059] Delay filter module deployment: Add a signal processing program in the central control PCS system, set a 2s delay filter logic, eliminate the interference of transient pressure fluctuations (such as pulse fluctuations during gas transportation) on trigger judgment, and the program diagram is shown in Figure 2 .

[0060] 3. Acquisition unit joint debugging:

[0061] Pressure signal calibration: Calibrate the near-point mechanical pressure switch and far-point pressure transmitter through a standard pressure source to ensure that the pressure measurement error is ≤±1%;

[0062] Signal transmission test: Simulate the near-point pressure from 24MPa to 16MPa and the far-point pressure from 30MPa to 22MPa, verify that there is no packet loss and no delay in the transmission process of the DO signal and AI signal, and the turbine control system and the central control PCS system can accurately receive the signal.

[0063] Self-adaptive threshold calculation module configuration and parameter setting:

[0064] 1. Basic parameter input:

[0065] In the self-adaptive threshold calculation module of the turbine control system, input the basic parameters of the unit operating condition:

[0066] Fixed parameters: gas buffer tank volume V = 30 m³, near point minimum stable operating pressure Pmin = 12 MPa, oil switching time tswitch = 1 min, pipeline transmission maximum loss ΔP = P01-P02 = 6 MPa;

[0067] Dynamic parameter interface: reserve the real-time gas consumption Q of the unit collection interface, calculate the dynamic gas consumption in real time through the feedback signal of the unit fuel regulating valve and the feedback signal of the gas regulating valve, and the update period is 1 s.

[0068] 2. Threshold value calculation logic deployment:

[0069] Based on the ideal gas state equation and the dynamic working condition correction model, the threshold value calculation program is written in the turbine control system, and the specific process is as follows:

[0070] Feasibility prediction calculation: through the formula t = V × (P0-Pmin) / Q, the turbine operating time t is calculated in real time, when t ≥ tswitch (1 min), it is determined that the current working condition meets the automatic oil switching condition, and the threshold value calculation module starts; when t < tswitch, the system sends a warning signal to prompt the operator to check the gas supply;

[0071] Near point dynamic threshold P1 calculation:

[0072] Theoretical optimal threshold: calculated by the formula P1opt = Pmin + (Q × tswitch) / V, for example, when Q = 66.7 m³ / min, P1opt = 12 + (66.7 × 1) / 30 ≈ 14.22 MPa;

[0073] Safety margin correction: considering the risk of ocean platform gas pressure fluctuation (such as unstable gas transmission caused by wind and wave), 1.78 MPa safety margin is reserved, and the near point dynamic threshold P1 = 16 MPa is finally determined;

[0074] Far point dynamic threshold P2 calculation: combined with the pipeline transmission loss ΔP = 6 MPa, the far point dynamic threshold P2 = 22 MPa is determined by the formula P2 = P1 + ΔP;

[0075] Threshold value self-adaptive update: set the working condition parameter change trigger condition, when the real-time gas consumption Q of the unit changes by more than ±10%, the threshold value calculation module re-executes the above calculation process to update P1 and P2, ensuring that the threshold value always adapts to the current working condition.

[0076] 3. Threshold parameter solidification and permission setting:

[0077] Parameter solidification: the initial threshold values P1 = 16 MPa and P2 = 22 MPa calculated are recorded in the turbine control system and the central control PCS system, and the parameter modification permission is set, only authorized operators can make calibration adjustments;

[0078] Threshold range limit: Set the threshold safety boundary, the adjustment range of P1 is 14MPa~18MPa, and the adjustment range of P2 is 20MPa~24MPa, to avoid abnormal oil transfer caused by parameter missetting.

[0079] Dual-path trigger module and switching control execution:

[0080] 1. Near-point emergency oil transfer path implementation:

[0081] Trigger logic: The mechanical pressure switch PS3701 adopts normally closed contact design. When the near-point gas pressure is higher than P1 (16MPa), the pressure will open the switch contact, and there is no signal output. When the pressure is ≤16MPa, the contact is closed, and the DO signal is output to the turbine control system.

[0082] Response mechanism: After the turbine control system receives the DO signal, it immediately starts the emergency oil transfer program, skips the delay judgment, and executes the gas mode to fuel mode switching according to the preset timing. The specific timing is: gas shut-off valve (XV3701, XV3702) closed → fuel purge shut-off valve (XV4002) opened → fuel ring pipe oil filling (filling time about 25s) → fuel nozzle started → gas mode exited, the whole oil transfer time ≤1min.

[0083] 2. Far-point predictive oil transfer path implementation:

[0084] Signal processing: After the pressure signal collected by the gas buffer tank pressure transmitter is converted into a 4-20mA AI signal, it is transmitted to the central control PCS system, and after 2s delay filtering processing, the transient fluctuation interference is eliminated.

[0085] Trigger logic: When the central control PCS system detects that the far-point pressure is ≤P2 (22MPa) and the duration is ≥2s, the DO signal is output to the turbine control system.

[0086] Response mechanism: After the turbine control system receives the signal, it starts the predictive oil transfer program and executes the oil transfer according to the smooth switching logic of "gradual reduction of gas supply → gradual increase of fuel supply", to avoid large power fluctuation and ensure that the unit power fluctuation is ≤300kW.

[0087] 3. Dual-path linkage and manual function compatibility:

[0088] Linkage mechanism: The near-point trigger signal and the far-point trigger signal are independent of each other. When either signal is valid, the turbine control system immediately executes the oil transfer program, and the two path signals do not conflict (when both signals are triggered at the same time, the timing of the near-point emergency oil transfer path is executed first).

[0089] Manual function reservation: The original control cabinet manual oil turning button is reserved. Manual trigger signal and automatic trigger signal are input into the turbine control system in parallel. The signal priority is set (manual signal priority is higher than automatic signal). When the operator triggers the manual oil turning, the automatic oil turning function is temporarily shielded. After switching is completed, it is automatically restored to ensure that there is no mechanical and logical conflict between manual and automatic modes.

[0090] Function test verification:

[0091] 1. Test working condition design:

[0092] Under the condition that the power grid hot standby is sufficient, tests are carried out under three typical working conditions of 1500 kW, 3000 kW and 5500 kW respectively. Two scenarios of natural gas pressure drop and sudden gas pressure drop are simulated. Each scenario is tested three times. The oil turning time, power fluctuation, trigger accuracy and other indicators are recorded.

[0093] 2. Test process and results:

[0094] Test working condition Simulation scenario Trigger path Oil transfer time Power fluctuation Trigger accuracy 1500 kW Natural drop in gas pressure Far-point pressure sensing type 52s 210 kW 100% 1500 kW Sudden drop in gas pressure Near-point mechanical pressure switch type 48s 250 kW 100% 3000 kW Natural drop in gas pressure Far-point pressure sensing type 55s 280 kW 100% 3000 kW Sudden drop in gas pressure Near-point mechanical pressure switch type 50s 290 kW 100% 5500 kW Natural drop in gas pressure Far-point pressure sensing type 58s 295 kW 100% 5500 kW Sudden drop in gas pressure Near-point mechanical pressure switch type 53s 300 kW 100%

[0095] The test results show that under the three working conditions, the automatic oil turning function can be accurately triggered. The oil turning time is less than or equal to 1 min. The power fluctuation is less than or equal to 300 kW, which meets the platform operation requirements. The double-path trigger has no conflict. The adaptive threshold can automatically fine-tune according to the small change (within ±5%) of gas consumption, ensuring the economy and safety of the oil turning opportunity.

[0096] 3. Manual-automatic switching test:

[0097] Trigger the manual oil turning button to verify that the automatic oil turning function is temporarily shielded. After manual oil turning is completed (oil turning time is 56 s and power fluctuation is 270 kW), the system automatically restores the automatic oil turning function and there is no logical conflict. Simulate the triggering of manual oil turning during the automatic oil turning process. The system immediately switches to manual control to ensure operational flexibility.

[0098] Operation and maintenance and threshold calibration:

[0099] 1. Regular maintenance cycle and content:

[0100] Daily inspection: Check the installation sealing of near-point mechanical pressure switch, the connection state of signal line, and verify the stability of remote-point pressure signal in PCS system;

[0101] Weekly calibration: Calibrate the near-point mechanical pressure switch and remote-point pressure transmitter through a standard pressure source to ensure the trigger accuracy of the threshold;

[0102] Monthly threshold review: Based on the actual operation data of the unit (such as the change trend of gas consumption and the fluctuation rule of gas pressure), review the rationality of the adaptive threshold and manually fine-tune if necessary.

[0103] 2. Fault handling mechanism:

[0104] Signal loss handling: When the near-point or far-point pressure signal is lost, the system automatically switches to another path to work alone and issues a fault warning; when both paths lose signal, the system locks the automatic oil transfer function and forces a switch to manual mode to avoid false triggering;

[0105] Threshold exception handling: When the adaptive threshold calculation result exceeds the safety boundary (P1<14MPa or P1>18MPa, P2<20MPa or P2>24MPa), the system maintains the last valid threshold and issues a warning, prompting the operator to check the working condition parameter acquisition interface.

[0106] This embodiment is based on the implementation of the marine platform turbine unit, but the control method of the present application is also applicable to other scenarios with high requirements for power supply reliability (such as land-based natural gas power stations, industrial production turbine units, etc.), only need to re-enter the basic parameters through the adaptive threshold calculation module according to the gas buffer tank volume, rated gas consumption, pressure operating range, etc. of the target unit, which can be quickly adapted without significant adjustment to the hardware structure.

[0107] Through the above specific embodiments, the present application realizes the adaptive adjustment of the turbine unit gas pressure threshold and the double-path automatic oil transfer, solves the problems of traditional manual oil transfer such as dependence on manual operation, response lag, fuel waste, etc., while retaining the manual function as a backup, greatly improving the stability, economy and reliability of the unit operation.

[0108] The present application is based on the implementation of a turbine unit that has completed dual-fuel modification on a certain marine platform in Wenchang, and through systematic hardware adaptation, software development and joint debugging and testing, the feasibility, stability and superiority of the turbine dual-fuel switching control method with adaptive gas pressure threshold have been fully verified. The entire implementation process focuses on solving industry pain points, optimizing operational efficiency, and reducing application barriers, fully reusing existing equipment resources, and breaking through the limitations of traditional manual oil transfer mode through precise technological innovation, providing a complete solution for turbine generator fuel switching control that is both scientific and practical.

[0109] From the perspective of technological innovation, the core breakthrough of the present application lies in the construction of a closed-loop control system with double acquisition, self-adaptation and double triggering, which completely changes the traditional mode of relying on manual judgment. The design of the double-pressure acquisition unit embodies the cooperative logic of near-point response and far-point prediction:

[0110] The near-point mechanical pressure switch is installed at the key node at the inlet side of the turbine, can quickly capture the emergency scene of pressure drop, and directly outputs a trigger signal through the normally closed contact to realize millisecond-level response of emergency oil switching and effectively avoid the shutdown risk of the unit caused by interruption of gas supply; the far-point pressure transmitter reuses the original equipment, and after delay filtering processing of the central control PCS system, can accurately identify the trend of pressure drop, and start the predictive oil switching in advance, which not only avoids the fuel waste caused by early oil switching, but also prevents the power fluctuation caused by late oil switching. The dual-path independent linkage mechanism not only guarantees the timeliness and accuracy of fuel switching, but also improves the system fault tolerance through signal backup, so that even if any path loses signal or fails, the other path can still complete the triggering task independently, and builds a safety line for unit operation.

[0111] The research and development and deployment of the adaptive threshold calculation module is a key support for realizing "accurate oil switching and economic operation". The invention discards the rigid mode of traditional fixed threshold, constructs a simplified model based on the ideal gas state equation, dynamically adjusts the pressure threshold combined with real-time operating parameters of the unit, and realizes real-time matching of the threshold and the operating state. The running time of the turbine is calculated to ensure the feasibility of oil switching, the near-point threshold is determined by calculating the theoretical optimal threshold combined with safety margin correction, and the far-point threshold is derived combined with pipeline transmission loss, the whole calculation process not only considers the scientificity and rigor, but also fully considers the pressure fluctuation characteristics of complex scenes such as offshore platforms. When the real-time gas consumption of the unit changes by more than ±10%, the system automatically recalculates the threshold to ensure accurate control of the oil switching time under different load conditions. In the test of three typical conditions of 5500kW, 3000kW and 1500kW, the oil switching time is controlled within 1min, and the power fluctuation is not more than 300kW, which not only meets the stringent requirements of the platform for power supply stability, but also maximizes the reduction of fuel consumption, and the fuel waste rate can be reduced by about 15%-20% through calculation, which significantly improves the economy of unit operation.

[0112] In terms of implementation compatibility and promotion value, the application shows strong practical advantages. The whole control method is implemented based on the completed dual-fuel modification of the unit, without substantial modification of the turbine main machine, core pipeline and other key equipment. The far-point pressure acquisition directly reuses the original pressure transmitter and central control PCS system, only the near-point mechanical pressure switch and the optimized control program need to be added, the modification cycle is short (only 15 days from equipment installation to commissioning completion), the cost is controllable (the cost of the added hardware is less than 5% of the total investment of the unit modification), and the compatibility with the original system is excellent, which can be quickly applied to various turbine units that have completed dual-fuel modification. At the same time, the design of the manual oil transfer function fully considers the use habits and emergency disposal needs of the operators, the manual and automatic modes run independently in parallel, there is no mechanical and logical conflict, and the priority of the manual signal is higher than that of the automatic signal, which not only guarantees the smooth transition of intelligent upgrading, but also reserves operation space for manual intervention in emergency scenarios, improving the operability and acceptance of the method.

[0113] From the implementation effect, the application of the application completely solves the many pain points of the traditional manual oil transfer mode. Test data shows that the trigger accuracy of automatic oil transfer under three typical working conditions reaches 100%, the oil transfer time is stably controlled between 48s-58s, and the power fluctuation is not more than 300kW, which fully meets the requirements of ocean platforms for power supply continuity and stability. Compared with manual oil transfer, the automatic switching mode does not require operators to monitor pressure data in real time, greatly reducing labor intensity, eliminating the risks caused by manual judgment errors and response lags, and effectively avoiding problems such as power grid fluctuations, fuel waste or unit shutdown caused by improper oil transfer time. In the actual operation of the ocean platform, the method successfully copes with complex scenarios such as gas delivery fluctuations and pipeline pressure pulse interference caused by wind and waves, ensuring the continuous operation of oilfield production and drilling operations, and its "automatic + manual" double protection mode provides higher level of reliability support for power supply in critical scenarios.

[0114] The value of the application is not limited to the application of a single ocean platform, but also has wide scene adaptability and industry promotion significance. In addition to ocean platforms, the control method can be quickly adapted to various scenarios with high requirements for power supply reliability, such as land natural gas power stations and industrial production turbine units, by adjusting basic parameters such as gas buffer tank volume, minimum stable operating pressure, pipeline transmission loss, etc. The core control logic can be migrated to dual-fuel turbine units of different power levels and different fuel types, especially suitable for unstable gas supply and large load fluctuation operating environments. At the same time, the technical idea of the application provides a useful reference for the intelligent upgrading of turbine generators, which realizes the performance improvement of traditional equipment through the mode of hardware lightweight modification + software intelligent optimization, and conforms to the current development trend of intelligent and energy-saving industrial equipment.

[0115] In terms of operation maintenance and sustainability, the present application builds a perfect guarantee system. Through the establishment of regular maintenance mechanism of daily inspection, weekly calibration and monthly threshold review, the measurement accuracy and signal transmission stability of the pressure acquisition equipment are ensured. In view of the fault scenes such as signal loss and threshold anomaly, the emergency treatment process is designed, the system can automatically switch the working mode and issue early warning, and the influence of failure on operation is reduced. The combination of precise control and standard maintenance not only ensures the long-term stable operation of the method, but also prolongs the service life of the equipment and further reduces the operation cost of the unit in the whole life cycle.

[0116] In summary, the turbine dual-fuel switching control method with adaptive gas pressure threshold solves the industry pain points through technical innovation, ensures the operation efficiency through precise implementation, and reduces the promotion threshold through compatible design. Its significant advantages in stability, economy and reliability make it the preferred solution for dual-fuel turbine unit fuel switching control. The successful implementation and promotion of the present application not only provides more reliable protection for power supply in scenarios such as offshore platforms and natural gas power stations, but also promotes the development of turbine generator control technology towards intelligence and adaptability, and injects new power for efficient and low-carbon operation of the energy industry. In the future, with the further optimization of technology, combined with technologies such as Internet of Things and big data analysis, the working condition parameters can be predicted in advance and the threshold can be accurately predicted, further improving the intelligent level of fuel switching and providing more comprehensive support for the safe, economic and stable operation of turbine units.

[0117] Embodiments of the present application are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the application to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are chosen and described in order to best explain the principles of the application and its practical application, and to enable others skilled in the art to understand the application for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. A turbine dual fuel switching control method with gas pressure threshold self-adaptation, applied to a turbine unit which has completed dual fuel modification, characterized in that, The original manual oil switching function is reserved, and the automatic switching from gas to oil is realized through double pressure acquisition, adaptive threshold calculation and double path triggering, including the following steps: S1: Constructing a double pressure acquisition unit: setting a near-point pressure acquisition end and a far-point pressure acquisition end, the near-point pressure acquisition end acquires the pressure at the gas inlet side of the turbine unit, and the far-point pressure acquisition end acquires the pressure in the gas buffer tank, the two-point acquisition signals are mutually backed up; S2: Building an adaptive threshold calculation module: real-time acquisition of unit operating condition parameters, dynamic calculation of near-point pressure threshold P1 and far-point pressure threshold P2 based on the ideal gas state equation and dynamic operating condition correction model, the operating condition parameters include gas buffer tank volume V, unit real-time gas consumption Q, near-point minimum stable operating pressure Pmin, oil switching time tswitch and pipeline transmission loss ΔP between near-point and far-point; S3: Configuring a double-path triggering module: the near-point pressure acquisition end outputs a triggering signal through a mechanical pressure switch, and the far-point pressure acquisition end outputs a triggering signal after delay filtering processing of the pressure sensing signal; S4: Switching control: when either path in the double-path triggering module meets the triggering condition, the turbine control system receives the signal and executes the switching program from gas mode to oil mode according to the preset timing, completing automatic oil switching.

2. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, In step S1: The installation position of the near-point pressure acquisition end is between the gas shutoff valve outside the turbine box and the first shutoff valve inside the box; The installation position of the far-point pressure acquisition end is the turbine gas buffer tank, and the original pressure sensor connected to the central control PCS system is used for pressure acquisition.

3. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, In step S1: The near-point pressure acquisition end uses a mechanical pressure switch, which uses normally closed contacts to connect to the turbine control system; The far-point pressure acquisition end uses a pressure transmitter to convert the acquired pressure signal into a 4-20mA AI signal and transmit it to the central control PCS system.

4. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, The calculation process of the adaptive threshold calculation module in step S2 includes: Based on the ideal gas state equation simplified model t=V×(P0-Pmin) / Q, calculate the turbine operating time t to ensure t≥tswitch; Calculate the near-point theoretical optimal threshold P1opt by the formula P1opt=Pmin+(Q×tswitch) / V, and get the dynamic threshold P1 after reserving a safety margin; Combine the pipeline transmission loss ΔP=P01-P02, and derive the far-point dynamic threshold P2=P1+ΔP.

5. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, The triggering logic of the near-point pressure acquisition end in step S3 is: when the near-point acquisition pressure ≤ dynamic threshold P1, the mechanical pressure switch contact is closed, and a DO signal is output to the turbine control system, triggering emergency oil switching.

6. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, The triggering logic of the far-point pressure acquisition end in step S3 is: the central control PCS system performs delay filtering processing on the received AI signal to eliminate transient pressure fluctuation interference, and when the far-point acquisition pressure ≤ dynamic threshold P2 and the duration ≥ 2s, a DO signal is output to the turbine control system, triggering predictive oil switching.

7. The gas pressure threshold adaptive turbine dual fuel switchover control method as described in claim 1, wherein, The linkage mechanism of the double-path trigger module in step S4 is that the near-point trigger signal and the far-point trigger signal are independent of each other, and when any signal is valid, the turbine control system immediately starts the oil transfer program, and the two path trigger signals do not conflict.

8. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, The adjustment mechanism of the adaptive threshold calculation module in step S2 is that when the variation amplitude of the real-time operating parameter of the unit exceeds the preset threshold ± 10%, the dynamic thresholds P1 and P2 are recalculated to realize real-time adaptive updating of the thresholds.

9. The gas pressure threshold adaptive turbine dual fuel switchover control method as claimed in claim 1, wherein, The reserved manual oil transfer function and the automatic oil transfer function can be independently operated, the manual trigger signal is generated through the control cabinet button, and the automatic trigger signal is input into the turbine control system in parallel, and there is no mechanical and logical conflict when the two are switched.

10. The gas pressure threshold adaptive turbine dual fuel switchover control method of claim 1, wherein, The execution standard of the oil transfer program in step S4 is that the oil transfer time is less than or equal to 1 min, and the unit power fluctuation is less than or equal to 300 kW.

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