A control method for a gas engine in an oil and gas production environment

Abstract

This invention discloses a gas engine control method for oil and gas extraction environments, belonging to the field of engine control technology. The method acquires control signals from the operating equipment in real time and compares them with a preset load characteristic database to identify the operating condition type and predict the load change curve. Before applying impact loads, it sends a speed pre-adjustment command to the electronic speed governor and synchronously adjusts the excitation response. When the predicted load exceeds the available margin of a single unit, it performs multi-unit peak shaving allocation based on the real-time available margin of each unit. Simultaneously, it calculates an intake air density correction coefficient based on sudden changes in environmental parameters to compensate for the pre-adjustment amount and executes safety interlocks based on combustible gas concentration levels. This invention achieves coordinated control of impact load pre-adjustment, multi-unit economic peak shaving, environmental adaptive compensation, and safety interlocks, improving the stability, economy, and safety of power supply at oil and gas extraction sites.

Description

Technical Field

[0001] This invention belongs to the field of engine control technology, specifically relating to a control method for a gas engine in an oil and gas extraction environment. Background Technology

[0002] In the oil and gas extraction sector, remote well sites typically use gas generator sets as the primary power source, utilizing associated gas at the wellhead or pipeline natural gas to drive drilling rigs, mud pumps, top drives, and other working equipment. Existing control strategies for gas generator sets are mostly designed based on steady-state conditions in plains areas. There is a lack of real-time data interaction between the engine control unit and the electrical equipment control unit, making it impossible to predict load changes in advance based on the control signals from the working equipment. This leads to air-fuel ratio mismatch and ignition timing lag when impact loads are applied, causing engine speed response lag, severe fluctuations in grid frequency and voltage, and even misfires or knocks. Furthermore, when multiple units operate in parallel, the load is only distributed equally according to active power, without considering the real-time availability margin of each unit, differences in gas consumption rates, and combustion boundary margins. This results in insufficient peak-shaving flexibility and low overall economic efficiency, and there is a risk that the unit operating point will approach the misfire or knock boundary. In addition, existing control systems lack a linkage response mechanism for fluctuations in the calorific value of gas at oil and gas extraction sites, sudden environmental changes such as high altitude and low pressure, high dust and air filter blockage, and the risk of combustible gas leaks, making it difficult to balance operational safety and power supply stability. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a gas engine control method for oil and gas extraction environments, which aims to maintain a high-efficiency operating state by coordinating the adjustment of combustion parameters of single and multiple engines according to changes in conditions.

[0004] The technical solution adopted in this invention is as follows:

[0005] In a first aspect, the present invention provides a gas engine control method for oil and gas extraction environments, comprising the following steps:

[0006] Real-time acquisition of control signals from oil and gas extraction site equipment and operating parameters from the generator output side;

[0007] The collected control signals are compared with the operating parameters and the preset load characteristic library to identify the current operating condition type and predict the load change curve and the actual load application time within a set time period in the future.

[0008] Based on the predicted load change curve and the current real-time availability margin of the unit, determine the speed pre-adjustment command, ignition advance angle pre-adjustment command, and air-fuel ratio pre-adjustment command.

[0009] Before the predicted load is actually applied to the engine crankshaft, a speed pre-adjustment command is sent to the electronic governor, an ignition advance angle pre-adjustment command is sent to the engine control unit, an air-fuel ratio pre-adjustment command is sent to the electronic throttle and gas control valve, and an excitation response adjustment command is sent to the generator control unit.

[0010] When the predicted load exceeds the real-time availability margin of the current units, peak shaving allocation of multiple units is performed based on the real-time availability margin of each parallel unit.

[0011] In conjunction with the first aspect, the present invention provides a first embodiment of the first aspect, which compares the collected control signals with operating parameters and a preset load characteristic library, including:

[0012] Extract the inverter frequency setpoint, programmable logic controller operating mode command, and hydraulic system pressure feedback value from the control signals;

[0013] The extracted parameters are matched with the standard control signal characteristics of four typical working conditions in the load feature library: drilling rig tripping, mud pump loading, top drive start-up, and conventional steady-state operation.

[0014] When the matching degree exceeds the preset threshold, the current operating condition type is determined, and the corresponding standard load change curve is called as the prediction benchmark.

[0015] In conjunction with the first aspect, the present invention provides a second embodiment of the first aspect, which predicts the load change curve and the actual load application time within a future set time period, including:

[0016] Based on the standard load change curve corresponding to the current operating condition, and combined with the rate of change and duration of the control signal, calculate the predicted load gap value within the future set time, and predict the actual time when the load is applied.

[0017] The gas calorific value correction coefficient is calculated based on the real-time air-fuel ratio and gas flow rate change rate fed back by the wide-range oxygen sensor, and the load gap prediction value is corrected accordingly.

[0018] The set time is determined based on the sum of the engine speed response lag period, the mechanical response lag period of the gas valve and electronic throttle, and the generator excitation response lag period.

[0019] In conjunction with the first aspect, the present invention provides a third embodiment of the first aspect, which determines the engine speed pre-adjustment command, the ignition advance angle pre-adjustment command, and the air-fuel ratio pre-adjustment command, including:

[0020] Based on the predicted load gap, engine rated speed, current unit real-time availability margin, ambient intake air density correction factor, and fuel gas calorific value correction factor, the speed pre-adjustment target increment is determined according to the following relationship:

[0021] ;

[0022] in, To pre-adjust the target increment for the rotational speed, The load-speed coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. The engine's rated speed. This is the correction factor for the calorific value of the gas. This is the environmental intake air density correction factor;

[0023] The combustion boundary margin is determined based on the distance between the current operating point and the calibrated misfire and knock boundaries. The ignition advance angle pre-adjustment target increment is determined according to the combustion boundary margin correction function. The air-fuel ratio pre-adjustment target increment is determined according to the ambient intake air density correction coefficient and the fuel gas calorific value correction coefficient.

[0024] In conjunction with the third embodiment of the first aspect, the present invention provides a fourth embodiment of the first aspect, which determines the combustion boundary margin based on the distance between the current operating point and the calibrated misfire boundary and detonation boundary, and determines the ignition advance angle pre-adjustment target increment according to the following relationship:

[0025] ;

[0026] in, To pre-adjust the target increment for ignition advance angle, The load-ignition coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. This is the reference ignition advance angle for the current operating condition. This is a combustion boundary margin correction function. It takes a positive value when the combustion boundary margin is greater than the preset safety threshold, and a negative value or zero when it is less than the preset safety threshold.

[0027] In conjunction with the first aspect, the present invention provides a fifth embodiment of the first aspect, which sends a coordinated pre-adjustment command before the predicted load is actually applied to the engine crankshaft, including:

[0028] The pre-adjustment trigger advance is determined based on the engine mechanical response lag period, the gas valve and electronic throttle mechanical response lag period, and the electrical system signal transmission lag period. At the pre-adjustment trigger advance moment when the predicted load is actually applied in front of the engine crankshaft, an air-fuel ratio pre-adjustment command is sent to the electronic throttle and gas control valve, an ignition advance angle pre-adjustment command is sent to the engine control unit, a speed pre-adjustment command is sent to the electronic governor, and an excitation response acceleration command is simultaneously sent to the generator control unit to increase the response rate of the excitation regulator by a preset ratio.

[0029] In conjunction with the first aspect, the present invention provides a sixth embodiment of the first aspect, which further includes a safety interlocking step:

[0030] Real-time acquisition of combustible gas concentration and engine combustion status parameters at the perimeter of the unit, including exhaust temperature, in-cylinder combustion pressure and air-fuel ratio fluctuation.

[0031] When the concentration of combustible gas reaches the warning threshold, the engine load rate is limited to a preset ratio and the cooling fan speed is increased.

[0032] When the concentration of combustible gas reaches the danger threshold, an orderly shutdown is carried out by first unloading and reducing the load to idle speed and then cutting off the gas supply.

[0033] When the combustion state parameters exceed the misfire boundary or knock boundary, the combustion protection action of delaying the ignition advance angle and enriching the air-fuel ratio is executed first.

[0034] The safety level switching setting has a hysteresis, which is the difference between the threshold for triggering a level increase when the concentration rises and the threshold for triggering a level decrease when the concentration falls, to avoid frequent switching of control strategies due to concentration fluctuations.

[0035] In conjunction with the first aspect, the present invention provides a seventh embodiment of the first aspect, which further includes an environmental change coupling adjustment step during the operation of the gas engine, as detailed below:

[0036] Real-time data collection of ambient atmospheric pressure, ambient temperature, air filter pressure difference, and gas intake pressure;

[0037] When environmental parameters change abruptly relative to the start-up calibration reference value and the change exceeds the preset environmental threshold, calculate the environmental intake air density correction coefficient.

[0038] Based on the gas intake pressure, the gas calorific value correction coefficient is calculated according to the real-time gas flow rate and feedback from the wide-range oxygen sensor.

[0039] The real-time available margin is corrected based on the ambient intake density correction coefficient and the fuel calorific value correction coefficient to match the available margin with the abrupt changes in ambient intake conditions and fuel calorific value.

[0040] The air-fuel ratio pre-adjustment command, ignition advance angle pre-adjustment command, and speed pre-adjustment target increment are determined based on the corrected real-time availability margin.

[0041] In conjunction with the seventh embodiment of the first aspect, the present invention provides an eighth embodiment of the first aspect, which calculates the ambient air intake density correction coefficient, including:

[0042] The altitude air density correction factor is calculated based on the ratio of real-time atmospheric pressure to the starting calibration reference atmospheric pressure, and the ratio of real-time ambient temperature to the starting calibration reference ambient temperature.

[0043] The air filter clogging correction factor is calculated based on the ratio of the real-time air filter differential pressure to the maximum allowable air filter differential pressure.

[0044] The ambient air density correction factor is obtained by multiplying the altitude air density correction factor by the air filter blockage correction factor.

[0045] In conjunction with the first aspect, the present invention provides a ninth embodiment of the first aspect, wherein, under the condition of multiple units supplying power to the same oil and gas well site power grid in parallel, each unit calculates its own gas consumption rate, real-time availability margin, and combustion boundary margin between the current operating point and the fire and detonation boundaries in real time, and interacts with the controller local area network bus.

[0046] Based on the differences in gas consumption rates among the units, the load of each unit is dynamically allocated according to the principle of equal incremental rate. The allocated load of each unit does not exceed the real-time available margin of the corresponding unit after reduction by the environmental intake air density correction coefficient. The combustion boundary margin between the operating point of each unit and the fire and detonation boundaries is not lower than the preset safety threshold. During the start-up and shutdown switching or load adjustment of the units, the rate of change of the load of a single unit per unit time is limited to not exceeding the preset rate threshold. When the fluctuation amplitude of the grid frequency exceeds the preset threshold, the load transfer is suspended.

[0047] In a second aspect, the present invention provides a system applied to the above-mentioned gas engine control method for oil and gas extraction environment, including an environment perception module, a load characteristic identification module, an engine control unit, a generator control unit and a multi-machine collaborative main control unit;

[0048] The environmental sensing module includes an atmospheric pressure sensor, an air filter differential pressure sensor, a combustible gas concentration detector, an ambient temperature sensor, and a gas pressure sensor, which are used to collect atmospheric pressure, air filter differential pressure, combustible gas concentration, ambient temperature, and gas intake pressure in the oil and gas extraction environment.

[0049] The load characteristic identification module is located on the generator output side and the control end of the working equipment. It is used to collect electrical parameters, gas flow, electronic throttle opening and wide-range oxygen sensor feedback, and to identify impact load events.

[0050] The engine control unit calculates the ambient intake air density correction coefficient and the gas calorific value correction coefficient based on the parameters collected by the environmental perception module, and performs adaptive compensation for the gas supply, air-fuel ratio and ignition timing, and sends a coordinated pre-adjustment command based on the impact load identification result.

[0051] The generator control unit synchronously adjusts the excitation response rate according to the coordinated pre-adjustment command;

[0052] The multi-machine collaborative main control unit communicates bidirectionally with the engine control unit and generator control unit of each unit through the controller area network bus, and performs economical load distribution under the condition of multi-machine parallel operation.

[0053] The beneficial effects of this invention are as follows:

[0054] This invention collects control signals from the working equipment and compares them with a preset load feature library to predict the load change curve in advance. Before the impact load is actually applied to the engine crankshaft, it sends air-fuel ratio, ignition advance angle and speed coordinated pre-adjustment commands based on the misfire / knock boundary margin, and simultaneously adjusts the excitation response to optimize the engine combustion parameters in advance, reduce the frequency drop, voltage sag and misfire or knock risk in the early stage of impact load application, and improve power supply stability.

[0055] This invention dynamically allocates power based on the real-time availability margin, gas consumption rate and combustion boundary margin of each unit under the condition of multiple units operating in parallel, and limits the load transfer rate and grid frequency fluctuations to avoid overload of a single unit, long-term low-load operation or operation point approaching the combustion danger boundary, thereby improving the gas economy and the uniformity of unit service life in the parallel operation of multiple units.

[0056] This invention monitors parameters such as atmospheric pressure, ambient temperature, air filter pressure difference, and gas intake pressure in real time during operation. When environmental conditions change abruptly relative to the starting calibration reference value, it calculates the ambient intake density correction coefficient and the gas calorific value correction coefficient and corrects the pre-adjustment of combustion parameters to match the engine output power with the changed ambient intake conditions and gas calorific value, thus avoiding combustion deterioration and power reduction under conditions of high altitude, air filter blockage, or fluctuating gas calorific value.

[0057] This invention collects real-time data on the concentration of combustible gases and combustion status parameters around the unit and responds in stages. At the warning level, it limits the load rate and enhances ventilation; at the danger level, it performs orderly shutdown; and at the abnormal combustion level, it implements ignition advance angle delay and air-fuel ratio enrichment protection. By linking environmental safety monitoring with engine combustion control strategies, this invention reduces the operational risks caused by combustible gas leaks or abnormal combustion at oil and gas extraction sites. Attached Figure Description

[0058] Figure 1 This is a flowchart of the gas engine impact load coordinated pre-adjustment method in an embodiment of the present invention;

[0059] Figure 2 This is a logic diagram of the multi-unit parallel peak-shaving allocation method in an embodiment of the present invention;

[0060] Figure 3 This is a flowchart of the environmental mutation coupling adjustment method in an embodiment of the present invention;

[0061] Figure 4This is a photograph of the gas engine being tested on a test bench in Embodiment 2 of the present invention;

[0062] Figure 5 The load characteristic curve of the gas engine in Embodiment 2 of the present invention;

[0063] Figure 6 This is a comparison curve of the sudden acceleration and deceleration speed regulation performance in Embodiment 2 of the present invention;

[0064] Figure 7 This is a schematic diagram of the detonation determination criteria in Embodiment 3 of the present invention;

[0065] Figure 8 This is a schematic diagram of the fire malfunction determination criteria in Embodiment 3 of the present invention;

[0066] Figure 9 This is a schematic diagram of combustion boundary margin control in Embodiment 3 of the present invention. Detailed Implementation

[0067] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0069] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0070] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0071] In the description of this application, it should be noted that the use of terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These terms are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the use of terms such as "first" and "second" in the description of this application is only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0072] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this application does not imply that the component is required to be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0073] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0074] Example 1:

[0075] This embodiment discloses a gas engine control method for oil and gas extraction environments, referring to... Figure 1 Specifically, it provides a full-cycle control scheme for a single gas generator set at an oil and gas extraction site, from pre-start-up, normal operation, high-load response to orderly shutdown.

[0076] In one implementation, the control system includes a load characteristic identification module, an engine control unit, a generator control unit, and a multi-machine collaborative main control unit. The load characteristic identification module is located on the generator output side and the control terminals of the working equipment, and collects inverter frequency setpoints, programmable logic controller operating mode commands, hydraulic system pressure feedback values, gas flow feedback values, and electronic throttle opening feedback values ​​via hardwiring or an industrial communication interface. The engine control unit and the generator control unit establish bidirectional real-time communication via a controller area network bus.

[0077] The control method in this embodiment includes the following steps:

[0078] The system collects control signals, operating parameters, and combustion status parameters of the equipment used in oil and gas extraction sites in real time. Control signals include inverter frequency settings, programmable logic controller (PLC) operating mode commands, and hydraulic system pressure feedback values. Operating parameters include three-phase current, three-phase voltage, active power, reactive power, power factor, and grid frequency from the generator output side. Combustion status parameters include air-fuel ratio from a wide-range oxygen sensor, in-cylinder combustion pressure from a cylinder pressure sensor, exhaust temperature from a turbine exhaust temperature sensor, and the actual ignition advance angle.

[0079] The collected control signals, operating parameters, and combustion status parameters are compared with a preset load characteristic library to identify the current operating condition type and predict the load change curve within a set future time period. The load characteristic library contains standard control signal characteristics and standard load change curves for four typical operating conditions: drilling rig tripping, mud pump loading, top drive start-up, and conventional steady-state operation.

[0080] Based on the predicted load change curve, the current real-time availability margin of the unit, the ambient intake air density correction coefficient, and the gas calorific value correction coefficient, the air-fuel ratio pre-adjustment command, ignition advance angle pre-adjustment command, and speed pre-adjustment command are determined. The real-time availability margin is the difference between the unit's rated power and the current actual output power.

[0081] Before the predicted load is actually applied to the engine crankshaft, an air-fuel ratio pre-adjustment command is sent to the electronic throttle and gas control valve, an ignition advance angle pre-adjustment command is sent to the engine control unit, a speed pre-adjustment command is sent to the electronic governor, and an excitation response adjustment command is sent to the generator control unit.

[0082] When the predicted load exceeds the real-time availability margin of the current unit, peak shaving allocation of multiple units is performed based on the real-time availability margin, gas consumption rate and combustion boundary margin of each parallel unit.

[0083] After the system is powered on, the pre-start procedure is also included: completing the self-test of communication between the sensor and the actuator, collecting parameters such as oil pressure, coolant temperature, battery voltage and gas intake pressure to determine the start access, and unlocking the start permission after the parameters meet the preset threshold; after receiving the start command, dynamically calculating the preheating time based on the ambient temperature and battery temperature, controlling the intake preheating device to perform preheating, controlling the engine to ignite and maintain idle speed after preheating is completed, and gradually increasing the speed and loading after the electrical parameters meet the stable conditions.

[0084] As one implementation method, the specific thresholds for determining start-up access are: engine oil pressure not lower than a preset pressure value, coolant temperature not lower than a preset temperature value, battery voltage not lower than a preset voltage value, and gas intake pressure within a preset pressure range. When all parameters simultaneously meet the corresponding thresholds, the start-up access conditions are deemed met, and engine start-up permission is unlocked.

[0085] Upon receiving the shutdown command, the following orderly shutdown steps are executed: first, the generator is gradually unloaded to no load, and then the engine is kept running at idle speed. During the idle speed operation, the cooling intensity is adjusted according to the temperature difference between the cooling water outlet temperature and the ambient temperature. When the cooling water outlet temperature drops to within the preset threshold, the gas supply is cut off.

[0086] During unloading, the engine control unit maintains the power grid frequency fluctuations within a preset frequency threshold. During idling, the cooling fan speed is dynamically adjusted based on the temperature difference between the coolant outlet temperature and the ambient temperature. As one implementation method, when the coolant outlet temperature drops below a preset temperature, the gas supply is cut off; after the gas supply is cut off, the cooling system continues to operate for a preset duration to prevent high-temperature carbon buildup in the unit.

[0087] In one implementation, the load characteristic identification module is connected to the control terminals of the drilling rig, mud pump, and top drive via hardwiring or industrial Ethernet to directly read the inverter frequency setpoint and programmable logic controller (PLC) operating mode instructions. Alternatively, the electrical parameters of the generator output side can be indirectly acquired through current and voltage transformers, and the high-speed sampling unit within the load characteristic identification module can calculate the active power change rate and power factor.

[0088] Working principle and operation process:

[0089] Under normal operating conditions, the engine control unit maintains steady-state speed regulation based on the current actual output power, while the generator control unit maintains closed-loop voltage regulation.

[0090] When drilling rigs, mud pumps, or top drives are about to start, the frequency setting of the inverter or the pressure feedback value of the hydraulic system at their control terminals changes first. This change precedes the actual mechanical load applied to the engine crankshaft. After the load characteristic identification module detects the change in the control signal, it compares it with the load characteristic library, identifies the operating condition type, and calls up the corresponding standard load change curve.

[0091] As one implementation method, the construction of the load characteristic library includes the following steps: collecting historical control signal data of drilling rigs, mud pumps, and top drives in typical operating cycles; extracting statistical characteristics of the rate of change of inverter frequency setpoint, the rise slope of hydraulic system pressure feedback value, and duration under each working condition; normalizing the statistical characteristics of each working condition to form a standard control signal characteristic vector; and establishing a mapping relationship between each working condition and the standard load change curve.

[0092] During matching, the similarity between the real-time acquired control signal feature vector and the standard feature vector is calculated. When the similarity exceeds a preset matching threshold, the current operating condition type is determined, and the corresponding standard load change curve is used as the prediction benchmark. The preset matching threshold is dynamically set according to the fluctuation range of the control signal for each operating condition to avoid false triggering during steady-state operation.

[0093] The engine control unit calculates the target speed increment based on the predicted load shortfall, the current real-time availability margin of the unit, the ambient intake air density correction factor, and the fuel gas calorific value correction factor, according to the following relationship:

[0094] ;

[0095] in, To pre-adjust the target increment for the rotational speed, The load-speed coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. The engine's rated speed. This is the correction factor for the calorific value of the gas. This is the correction factor for the ambient air intake density.

[0096] Then calculate the target increment for ignition advance angle adjustment according to the following relationship:

[0097] ;

[0098] in, To pre-adjust the target increment for ignition advance angle, The load-ignition coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. This is the reference ignition advance angle for the current operating condition. This is a combustion boundary margin correction function. It takes a positive value when the combustion boundary margin is greater than the preset safety threshold, and a negative value or zero when it is less than the preset safety threshold.

[0099] Simultaneously, based on the ambient intake air density correction coefficient and the gas calorific value correction coefficient, the air-fuel ratio pre-adjustment target increment is determined, and a coordinated pre-adjustment command is sent to the electronic throttle, gas control valve, electronic governor, and engine control unit before the predicted load is actually applied.

[0100] The generator control unit synchronously receives the excitation response acceleration command and improves the excitation current response rate. As a result, at the moment the load is actually applied, the engine speed has been increased in advance, the air-fuel ratio has been optimized in advance, the ignition advance angle has been adjusted in advance, and the generator excitation has been enhanced in advance, thus suppressing frequency drops, voltage dips, and combustion abnormalities.

[0101] Example 2:

[0102] This embodiment verifies the control method for a single gas generator set under impact loads such as drilling rig tripping and mud pump loading in a standard well site environment for oil and gas extraction. The test environment was atmospheric pressure of approximately 95 kPa, ambient temperature of approximately 20°C, and atmospheric humidity of approximately 6 g / kg.

[0103] As one implementation method, the test used a certain type of 12L gas engine with a rated power of about 300kW, a rated speed of 1500r / min, a compression ratio of about 12:1, matched with a high-pressure gas control system, and equipped with an ECU, gas control valve, electronic throttle, wide-range oxygen sensor and surge valve.

[0104] Reference Figure 4 The photos show the actual test setup of the gas engine on the test bench, demonstrating the actual connection status of the engine with the control system, calibration software, and communication tools.

[0105] During the load characteristic calibration phase, refer to Figure 5 The engine load characteristic curve shows that the unit's rated power generation is approximately 250kW, the engine's maximum mechanical power is approximately 280kW, the minimum gas consumption rate is approximately 210g / kWe.h, the engine's turbine inlet exhaust temperature meets the design target requirements, and the NOx emissions under all operating conditions meet the requirements. Table 1 shows the test data at partial load points:

[0106] Table 1. Partial load test data for a certain type of gas engine

[0107] 1500 1680 250 240 320 495 0.7 43 24.0° 1500 1580 235 232 305 482 0.7 42 24.8° 1500 1450 215 215 288 485 0.7 40 25.2° 1500 1280 190 192 260 488 0.7 38 25.6° 1500 1100 165 165 235 495 0.71 36 26.0° 1500 920 138 142 208 490 0.71 34 26.2° 1500 740 110 118 178 500 0.72 32 26.6° 1500 560 85 92 150 505 0.73 30 26.8° 1500 380 58 72 128 525 0.75 27 27.0° 1500 200 32 48 110 535 0.82 23 26.0°

[0108] During the speed regulation performance calibration phase, refer to Figure 6 The comparison curves of sudden speed increase and decrease performance show that under a sudden increase of approximately 80kW, the frequency deviation is controlled at approximately -8%, and the recovery time is approximately 0.4s; under a sudden increase of approximately 120kW (approximately 40% of rated load), the frequency deviation is approximately -11%, and the recovery time is approximately 0.8s; under a sudden decrease of approximately 80kW, the frequency deviation is approximately 8%, and the recovery time is approximately 0.5s; under a sudden decrease of approximately 120kW, the frequency deviation is approximately 10%, and the recovery time is approximately 0.7s.

[0109] During the speed regulation performance calibration phase, refer to Figure 6 The speed regulation performance curves for sudden increase and decrease show that the unit meets the requirements of the main power standard for sudden increase frequency deviation ≥ -12% and recovery time ≤ 3s under sudden increase and decrease power conditions of about 80kW and about 120kW, and for sudden decrease frequency deviation ≤ 10% and recovery time ≤ 3s. Moreover, the unit responds quickly under small load sudden increase conditions.

[0110] In conjunction with the control method of this invention, before the drilling rig applies the impact load, the load characteristic identification module collects the control signal changes by hard-wired, such as the frequency setting value of the drilling rig control system inverter jumping from low frequency to high frequency and the hydraulic system pressure feedback value increasing at a certain rate. After comparing with the load characteristic database, it is identified as a drilling rig-type impact load event.

[0111] The set time is determined based on the sum of the engine speed response lag period, the mechanical response lag period of the gas valve and electronic throttle, and the generator excitation response lag period.

[0112] As one implementation method, the speed response lag period is the time required for the engine to reach 90% of the target speed from receiving the speed command; the mechanical response lag period of the gas valve and electronic throttle is the time required for the actuator to reach 90% of the target opening from receiving the opening command; and the generator excitation response lag period is the time required for the excitation regulator to reach 90% of the target output voltage from receiving the command. The pre-adjustment trigger advance is determined based on the sum of the above three factors to ensure that the engine combustion parameters and generator excitation have been adjusted before the actual application of the impact load.

[0113] The engine control unit predicts a load shortfall of approximately 60kW within the next 2.0 seconds based on the standard load change curve. The current real-time available capacity of the unit is approximately 80kW. The gas calorific value correction factor and the ambient intake air density correction factor are both set to 1.0. The load-speed coupling coefficient, calibrated on a test bench, is set to 0.24. The target speed pre-adjustment increment is calculated using Equation 1 in the embodiment, yielding a target speed pre-adjustment increment of approximately 180 r / min. Approximately 1.5 seconds before the actual application of the impact load, the engine control unit sends a speed pre-adjustment command to the electronic governor, increasing the target speed from the current approximately 1200 r / min to approximately 1380 r / min.

[0114] Simultaneously, based on the current operating condition point calibrated reference ignition advance angle of approximately 24° BTDC and the combustion boundary margin, the target increment for ignition advance angle pre-adjustment is calculated according to the relationship in Example 2. The load-ignition coupling coefficient is calibrated to 0.08, and the combustion boundary margin correction function is set to 1.0. The calculated target increment for ignition advance angle pre-adjustment is approximately 2°. An ignition advance angle pre-adjustment command is sent to the engine control unit, resulting in an ignition advance angle of approximately 26° BTDC. An air-fuel ratio pre-adjustment command is also sent to the electronic throttle and gas control valve, adjusting the air-fuel ratio from approximately 0.73 to approximately 0.71. Simultaneously, an excitation response acceleration command is sent to the generator control unit, increasing the excitation response rate by approximately 30% from the reference value.

[0115] After the actual application of the impact load, the unit's output power steadily increased from about 220kW to about 280kW, the grid frequency fluctuation was controlled within ±0.25Hz, the voltage sag was about 4%, the in-cylinder burst pressure did not exceed the low knock intensity threshold, and the recovery time was about 0.4s, meeting the requirements for continuous operation of well site equipment.

[0116] After sending the coordinated pre-adjustment command, the engine control unit collects the actual engine speed, air-fuel ratio, and in-cylinder combustion pressure in real time. When the actual speed increase rate is less than 80% of the preset rate, additional fuel gas compensation is added; when the actual speed overshoot exceeds the preset overshoot threshold, the fuel gas supply is reduced to prevent the speed from skyrocketing; when the in-cylinder combustion pressure exceeds the low knock intensity threshold, combustion protection actions of ignition advance angle retardation and air-fuel ratio enrichment are executed.

[0117] After sending the coordinated pre-adjustment command, the engine control unit collects the actual engine speed, air-fuel ratio, and in-cylinder combustion pressure in real time, forming a closed-loop feedback of the pre-adjustment effect. When the actual speed increase rate is less than 80% of the preset rate, additional fuel gas compensation is added; when the actual speed overshoot exceeds the preset overshoot threshold, the fuel gas supply is reduced to prevent the speed from skyrocketing; when the in-cylinder combustion pressure exceeds the low knock intensity threshold, combustion protection actions such as ignition advance angle retarding and air-fuel ratio enrichment are executed; when the in-cylinder combustion pressure is lower than the misfire threshold or the exhaust temperature drops abnormally, combustion recovery actions such as ignition advance angle advancing and air-fuel ratio enrichment are executed.

[0118] Example 3:

[0119] This embodiment verifies the combustion boundary control and high / low speed switching stability of a gas engine under a high-load continuous operation scenario.

[0120] The test environment was as follows: intake resistance less than 6 kPa, exhaust back pressure less than 10 kPa, engine coolant temperature approximately 75°C to 85°C, intercooler temperature approximately 20°C to 25°C, atmospheric pressure approximately 100 kPa, ambient temperature approximately 25°C, ambient humidity approximately 10 g / kg, fuel gas source pressure approximately 500 kPa to 700 kPa, and fuel gas source calorific value approximately 33 MJ / Nm³.

[0121] As one implementation method, the test used a certain type of 20L gas engine, 6 cylinders, rated power of about 400kW, rated speed of 1500r / min, compression ratio of about 12.5:1, Miller cycle, matched with medium pressure intake closed loop control system, and equipped with ECU, gas control valve, electronic throttle, wide range oxygen sensor, surge valve, combustion analyzer and cylinder pressure sensor.

[0122] During the boundary demarcation phase for fire and detonation, refer to Figure 7 The diagram illustrating the detonation criteria shows the concepts of detonation analysis window and intensity threshold.

[0123] Under a certain high load power, based on the cylinder pressure curve and engine operating sound, the knock analysis starts at approximately 0°CA and ends at approximately 40°CA, setting a low knock intensity threshold P. low With high detonation intensity threshold P high The knock ratio threshold R% is determined to be a knock event when the peak cylinder pressure exceeds the low knock intensity threshold and the knock ratio exceeds the threshold.

[0124] Reference Figure 8 The diagram illustrating the misfire determination criteria demonstrates the concept of the IMEP threshold. It sets the misfire IMEP threshold M based on a comprehensive assessment of cylinder pressure curves, exhaust temperature, and engine speed changes. low With slow burning IMEP threshold M high When the IMEP is below the misfire threshold or above the slow combustion threshold, it is determined to be an abnormal combustion event.

[0125] Reference Figure 9 The combustion boundary margin control diagram illustrates the control logic of the safe operating area and calibration point. At 100% load, the knock margin for each power range is controlled above the preset safety threshold (e.g., not less than 6°CA), meeting usage requirements.

[0126] During the engine performance calibration phase, the engine has a rated power of approximately 400kW, a 110% overload power of approximately 440kW, a fuel consumption rate of approximately 195g / kWh, a thermal efficiency of approximately 39% based on fuel calorific value, and a maximum throttle opening of approximately 40%, meeting the speed regulation performance requirements within the operating window. Refer to the following two tables:

[0127] Table 2 Schematic diagram of combustion boundary determination criteria

[0128] Detonation detection Detonation analysis starting angle °CA Approximately 0 Detonation detection End angle of detonation analysis °CA Approximately 40 Detonation detection Low knock intensity threshold Bar Set to P low ]] Detonation detection High detonation intensity threshold Bar Set to P high ]] Detonation detection Knock ratio threshold % Set to R% Fire determination Fire IMEP threshold Bar Set to M low ]]> Fire determination Slow Burning IMEP Threshold Bar Set to M high ]]

[0129] Table 3 Key performance parameters of a certain type of large-displacement gas engine

[0130] Rated power Approximately 400 kW 110% overload power Approximately 440 kW Rated speed 1500 rpm Compression ratio Approximately 12.5:1 - Gas consumption rate Approximately 195 g / kWh Thermal efficiency Approximately 39 % Maximum throttle opening Approximately 40 % Knock margin in each load section Not lower than the preset safety threshold °CA

[0131] In conjunction with the control method of this invention, under a certain high-load continuous operation condition, the load characteristic identification module collects the real-time feedback values ​​of gas flow rate and air-fuel ratio from the wide-range oxygen sensor, and calculates the gas calorific value correction coefficient. The calibrated calorific value is approximately 33 MJ / Nm³. 3 When the real-time estimated calorific value deviates from the calibration value, the gas calorific value correction factor is equal to the ratio of the calibration calorific value to the real-time estimated calorific value, and the load gap prediction value is corrected.

[0132] When predicting load changes, the engine control unit determines the combustion boundary margin based on the distance between the current operating point and the calibrated misfire and knock boundaries.

[0133] Reference Figure 9 With a reference ignition advance angle of approximately 24° BTDC at 100% load point and sufficient knock margin (e.g., approximately 7° CA), the combustion boundary margin is sufficient. The load-ignition coupling coefficient is calibrated to be within the range of 0.05 to 0.10, and the combustion boundary margin correction function is taken as a coefficient greater than 1.0. The allowable ignition advance angle pre-adjustment target increment is approximately 2°, and the pre-adjusted ignition advance angle is approximately 26° BTDC.

[0134] When a sudden increase in load causes the combustion margin to drop below a preset safety threshold, the combustion margin correction function takes a coefficient less than 1.0, limiting the ignition advance angle pre-adjustment to approximately 1°. Simultaneously, an air-fuel ratio enrichment command is sent to the electronic throttle and gas control valve, adjusting the air-fuel ratio from approximately 0.71 to approximately 0.69 to ensure that the in-cylinder combustion pressure does not exceed the low knock intensity threshold. When the in-cylinder combustion pressure falls below the misfire IMEP threshold or an abnormal drop in exhaust temperature is determined to indicate a misfire trend, the combustion margin correction function takes a coefficient greater than 1.0, allowing an increase in the ignition advance angle pre-adjustment and simultaneously enriching the air-fuel ratio to raise the in-cylinder combustion temperature and restore stable combustion.

[0135] In multi-unit parallel operation, the multi-unit collaborative main control unit dynamically allocates load according to the principle of equal incremental rate, and the combustion boundary margin between the operating point of each unit and the fire and detonation boundaries is not lower than the preset safety threshold. When the combustion boundary margin of a unit drops to near the preset safety threshold, the main control unit suspends the allocation of new load to that unit and prioritizes the transfer of load to units with sufficient combustion boundary margin to avoid the operating point approaching the detonation or fire hazard zone.

[0136] Example 4:

[0137] This embodiment verifies load characteristic calibration, power generation efficiency, and multi-unit peak-shaving allocation strategies under the dry environment of an oil and gas extraction site. The test environment is an atmospheric pressure of approximately 95 kPa, an ambient temperature of approximately 20°C, and an atmospheric humidity of approximately 4 g / kg.

[0138] As one implementation method, the test used a certain type of 15L gas engine with a rated power of about 320kW, a rated speed of 1500r / min, a compression ratio of about 11.5:1, matched with a high-pressure gas control system, and equipped with an ECU, gas injection system, ignition system, electronic throttle, wide-range oxygen sensor and surge valve.

[0139] During the load characteristic and performance calibration phase, the rated power generation is approximately 280kW, the maximum mechanical power of the engine is approximately 300kW, the minimum gas consumption rate is approximately 200g / kWe.h, and the gas consumption rate is approximately 0.28Nm. 3 / kW.h, with a rated power point power generation efficiency of approximately 38%. The engine turbine exhaust temperature meets the design target requirements, and the exhaust temperature of each cylinder meets the technical requirements.

[0140] Table 4. Partial load test data of a certain type of medium-displacement gas engine

[0141] 1500 1850 280 210 260 665 0.69 40 29.0° 1500 1750 265 205 248 668 0.69 39 29.0° 1500 1620 245 192 235 662 0.69 38 29.0° 1500 1500 228 180 220 660 0.69 37 29.0° 1500 1380 210 168 208 662 0.7 36 29.0° 1500 1250 190 155 195 665 0.71 34 29.5° 1500 1120 170 140 182 670 0.72 33 30.0° 1500 980 150 128 170 670 0.74 31 30.0° 1500 850 130 115 158 672 0.76 29 30.5° 1500 720 110 102 148 670 0.78 27 31.0°

[0142] The power generation efficiency trends of each power segment match the load characteristics. The power generation efficiency at the rated power point is about 38%, and the efficiency of partial load decreases as the load rate decreases.

[0143] When the load is suddenly increased by about 80kW (about 29% of the rated load), the speed drops to about 1430rpm, and the recovery time is about 3.0s; when the load is suddenly increased by about 120kW (about 43% of the rated load), the speed drops to about 1410rpm, and the recovery time is about 3.5s; when the load is suddenly increased by about 150kW (about 54% of the rated load), the speed drops to about 1380rpm, and the recovery time is about 3.8s; when the load is suddenly reduced by about 80kW, the speed rises to about 1570rpm, and the recovery time is about 1.2s; when the load is suddenly reduced by about 120kW, the speed rises to about 1575rpm, and the recovery time is about 1.4s; when the load is suddenly reduced by about 150kW, the speed rises to about 1600rpm, and the recovery time is about 1.6s.

[0144] Table 5. Speed ​​regulation performance data of a certain type of medium-displacement gas turbine engine under sudden acceleration and deceleration.

[0145] A sudden increase of approximately 80kW (30%) Approximately 1430 Approximately 3.0 ≥1350rpm, ≤5s A sudden increase of approximately 120kW (40%) Approximately 1410 Approximately 3.5 ≥1350rpm, ≤5s A sudden increase of approximately 150kW (50%) Approximately 1380 Approximately 3.8 ≥1350rpm, ≤5s Approximately 80kW (30%) was suddenly unloaded. Approximately 1570 Approximately 1.2 ≤1680rpm, ≤5s Approximately 120kW (40%) was unloaded suddenly. Approximately 1575 Approximately 1.4 ≤1680rpm, ≤5s Approximately 150kW (50%) was unloaded suddenly. Approximately 1600 Approximately 1.6 ≤1680rpm, ≤5s

[0146] All of the above indicators meet the G2 performance level standard.

[0147] In conjunction with the control method of this invention, in the parallel operation of multiple generators in an oil and gas well site under dry conditions, three gas generator sets of the same or different models are configured to form an islanded microgrid. The engine control unit of each generator set calculates the local gas consumption rate, real-time availability margin, and combustion boundary margin between the current operating point and the misfire and detonation boundaries in real time, and interacts with the multi-generator collaborative main control unit through the controller area network bus.

[0148] As a theoretical calculation example based on the load characteristics data of a single unit, a remote well site is equipped with three gas generator units with a rated power of approximately 320kW operating in parallel, with a total load demand of approximately 700kW. Unit A is a new unit with approximately 500 hours of operation, a gas consumption rate of approximately 0.20kg / kWh, currently operating at approximately 300kW, with a real-time available margin of approximately 20kW and a combustion boundary margin of approximately 9°CA; Unit B has been operating for approximately 4000 hours, with a gas consumption rate of approximately 0.24kg / kWh, currently operating at approximately 250kW, with a real-time available margin of approximately 70kW and a combustion boundary margin of approximately 8°CA; Unit C has been operating for approximately 10000 hours, with an equivalent rated power of approximately 288kW after introducing an aging factor of 0.90, currently operating at approximately 150kW, a gas consumption rate of approximately 0.27kg / kWh, a real-time available margin of approximately 138kW, and a combustion boundary margin of approximately 7°CA.

[0149] The equal incremental rate load allocation includes: fitting a characteristic curve of the unit's gas consumption rate as a function of load based on the gas consumption rate data of each unit at different load points; calculating the marginal gas consumption rate of each unit at the current load point, i.e., the slope of the characteristic curve at the current load point; and iteratively adjusting the load allocation ratio of each unit with the goal of making the marginal gas consumption rates of each unit equal. During the iteration process, if the load allocation value of a unit exceeds its maximum allowable load after being limited by the real-time availability margin, or causes the combustion boundary margin of the unit to fall below the preset safety threshold, then the load of that unit is locked to its maximum allowable load or safety boundary load, and the remaining load demand is redistributed by other units according to the equal incremental rate principle.

[0150] The multi-unit collaborative control unit dynamically allocates the load of each unit based on the differences in gas consumption rates and according to the principle of equal incremental rate. Unit A undertakes approximately 300kW, Unit B undertakes approximately 250kW, and Unit C undertakes approximately 150kW. At this time, the marginal gas increment of each unit tends to be equal, and the combustion boundary margin of each unit is not lower than the preset safety threshold.

[0151] As one implementation method, if the load of unit B is allocated to approximately 330kW according to the principle of equal incremental rate, but the combustion boundary margin at this load point will drop to 5°CA, then the main control unit will prioritize the execution of combustion boundary constraints, limiting the load of unit B to approximately 320kW, and transferring the remaining approximately 10kW load to unit C. At this time, the marginal gas consumption rate of unit C is slightly higher than that of unit B, but it ensures that none of the units enter the combustion hazard zone.

[0152] The mud pump suddenly started operating, with a predicted load shortfall of approximately 150kW, exceeding the real-time availability margin of Unit A. The main control unit initiated load transfer: Unit A's load was increased from approximately 300kW to approximately 320kW, reaching its upper limit, absorbing an increase of approximately 20kW; the remaining approximately 130kW load was allocated to Units B and C according to a uniform incremental rate principle. Unit B's load was increased from approximately 250kW to approximately 320kW, and Unit C's load was increased from approximately 150kW to approximately 210kW. The transfer rate was approximately 10% of rated power per minute. During the transfer, the grid frequency fluctuated by ±0.2Hz, without triggering the shutdown condition. Based on the load characteristic data, Unit B's gas consumption rate at approximately 320kW load point was approximately 205g / kWh, and Unit C's gas consumption rate at approximately 210kW load point was approximately 210g / kWh, both within the economic load zone.

[0153] After the transfer was completed, Unit A's load was approximately 320kW, Unit B's load was approximately 320kW, and Unit C's load was approximately 210kW, with a total load of approximately 850kW. The total gas consumption was approximately 197.5kg / h, compared to approximately 201.2kg / h for the even distribution strategy (approximately 283kW each), resulting in a gas saving of approximately 3.7kg per hour and an energy saving rate of approximately 1.8%. Furthermore, none of the units entered the fire or detonation hazard zone.

[0154] Preferably, during unit start-up / shutdown switching or load adjustment, the rate of change of load of a single unit within a unit time is limited to not exceeding a preset rate threshold. As one implementation method, the preset rate threshold is approximately 10% of rated power per minute. Another alternative is to dynamically adjust based on the magnitude of grid frequency fluctuations: when frequency fluctuations exceed ±0.2Hz, load transfer is suspended and the current state is maintained until the frequency recovers.

[0155] Example 5:

[0156] This embodiment corresponds to the coupled control strategy in the aforementioned control method when environmental abrupt changes and shock loads occur simultaneously, referring to... Figure 2 and Figure 3 This paper provides an optimization solution for a special scenario where sudden changes in harsh environmental conditions are superimposed on large-load power fluctuations of working equipment.

[0157] As one implementation method, this special scenario includes: a sudden drop in atmospheric pressure at high altitudes, rapid clogging of air filters in low-temperature environments, fluctuations in the calorific value of fuel gas, and simultaneous impact load demands such as drilling rig tripping or mud pump loading.

[0158] The coupling control strategy in this embodiment includes the following steps:

[0159] When the environmental sensing module detects that changes in atmospheric pressure, ambient temperature, air filter pressure differential, or gas pressure relative to the start-up calibration reference value exceed preset environmental thresholds, it first calculates the ambient intake air density correction coefficient and the gas calorific value correction coefficient, and then corrects the current real-time availability margin of the unit based on these coefficients. The corrected real-time availability margin is equal to the original real-time availability margin multiplied by the ambient intake air density correction coefficient and then divided by the gas calorific value correction coefficient. As one implementation, the original real-time availability margin is the difference between the unit's rated power and the current actual output power. For example, when the rated power is approximately 400kW and the current operating power is approximately 100kW, the original real-time availability margin is approximately 300kW. When the ambient intake air density correction coefficient is lower than 0.85, it is determined to be a severe environmental degradation, and the real-time availability margin is linearly reduced by the coefficient.

[0160] The load characteristic identification module synchronously acquires control signals from the working equipment, identifies impact load events, and predicts the load gap. Based on the corrected real-time availability margin and the predicted load gap, the engine control unit determines the initial air-fuel ratio pre-adjustment command, the initial ignition advance angle pre-adjustment command, and the initial speed pre-adjustment target increment.

[0161] Furthermore, the initial air-fuel ratio pre-adjustment command, the initial ignition advance angle pre-adjustment command, and the initial speed pre-adjustment target increment are further corrected based on the ambient intake air density correction coefficient and the fuel gas calorific value correction coefficient.

[0162] In one implementation method, the second-corrected engine speed preset target increment is equal to the initial engine speed preset target increment divided by the ambient intake air density correction coefficient and then multiplied by the fuel gas calorific value correction coefficient. The second-corrected ignition advance angle preset target increment is reverse-corrected according to the fuel gas calorific value correction coefficient. When the fuel gas calorific value correction coefficient is greater than 1.1, the ignition advance angle preset amount is reduced to suppress knocking. The second-corrected air-fuel ratio preset command is positive-corrected according to the ambient intake air density correction coefficient. When the ambient intake air density correction coefficient is less than 0.85, the air-fuel ratio is enriched to maintain combustion stability. When the ambient intake air density correction coefficient is less than 0.85, the compensation ratio of the fuel gas supply is also increased simultaneously to match the preset engine output power with the changed ambient intake conditions and fuel gas calorific value.

[0163] When the corrected real-time availability margin is still insufficient to cover the predicted load gap after the second correction, the multi-unit collaborative control unit immediately triggers multi-unit peak shaving allocation. Based on the corrected real-time availability margin, gas consumption rate, and combustion boundary margin reported by each unit, the control unit recalculates the equal incremental rate load allocation scheme, prioritizing the allocation of the new load to units with higher ambient air density correction coefficients, gas calorific value correction coefficients close to 1.0, sufficient real-time availability margins, and sufficient combustion boundary margins.

[0164] As one implementation method, if the grid frequency fluctuation exceeds ±0.3Hz during the load transfer process, the load transfer is suspended, and the units with pre-adjusted combustion parameters first bear the impact load. The allocation plan is then implemented again after the frequency stabilizes.

[0165] Another alternative is to prioritize limiting the load rate of units in areas of sudden change in harsh environment when the combustible gas concentration detector detects that the methane concentration has reached the warning threshold, and transfer the load to units with relatively stable environmental conditions and sufficient combustion boundary margin, so as to achieve a balance between safety and efficiency.

[0166] The coupling control strategy in this embodiment follows a progressive logic: environmental perception corrects available margin, load forecast determines pre-adjustment amount, secondary correction compensates for environmental deviation, and multi-machine peak shaving as a fallback.

[0167] The environmental perception module prioritizes responding to sudden environmental changes because the ambient intake air density and the calorific value of the fuel directly determine the actual work capacity of the unit. If the available margin is not corrected in time, subsequent load forecasting and pre-adjustment calculations will be based on an incorrect power reference, resulting in insufficient or excessive pre-adjustment. The load characteristic identification module responds synchronously to the impact load forecast because the application time of the impact load is determined by the operating equipment control signal and is independent of the environmental changes. Based on the available margin and pre-adjustment after the two corrections, the engine control unit determines whether to trigger multi-engine peak shaving, forming a four-layer collaborative closed loop of environment-load-combustion-multi-engine.

[0168] At a high-altitude gas field, approximately 3000m above sea level and with an ambient temperature of around -15℃, the air filter pressure differential suddenly increased from its normal value to a higher value during unit operation, while the gas pressure fluctuated from its normal value to a lower value. Simultaneously, the drilling rig was performing a tripping operation, with a predicted load shortfall of approximately 400kW. A large-displacement gas engine with a rated power of approximately 400kW and a compression ratio of approximately 12.5:1, using the Miller cycle, was employed.

[0169] After adopting the coupled control strategy of this embodiment, the system first corrects the real-time available margin from approximately 550kW to approximately 480kW. The target increment of the engine speed pre-adjustment after the second correction is increased by approximately 15%. The ignition advance angle pre-adjustment is reduced from approximately 3° under normal operating conditions to approximately 2° to suppress knocking. The air-fuel ratio pre-adjustment is adjusted from approximately -0.02 under normal operating conditions to approximately -0.03 to enrich the mixture, and the fourth standby unit is triggered to connect to the grid. During the application of the impact load, the grid frequency fluctuation is controlled within ±0.4Hz, the in-cylinder explosion pressure does not exceed the low knock intensity threshold, and no shutdown or tripping events occur.

[0170] It should be understood that the parameters in the above examples are only examples under specific implementation conditions, and in actual applications, they can be adaptively adjusted according to the unit model, well site environment, and load characteristics. Another alternative is to prioritize starting the standby unit in hot standby mode when the predicted load gap exceeds the real-time availability margin of a single unit and all parallel units are under high load, rather than simply relying on load transfer, in order to ensure grid stability.

[0171] This invention is not limited to the optional embodiments described above, and anyone can derive other various forms of products based on the inspiration of this invention. The specific embodiments described above should not be construed as limiting the scope of protection of this invention; the scope of protection of this invention should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A gas engine control method for oil and gas extraction environments, characterized in that, Includes the following steps: Real-time acquisition of control signals from oil and gas extraction site equipment and operating parameters from the generator output side; The collected control signals are compared with the operating parameters and the preset load characteristic library to identify the current operating condition type and predict the load change curve and the actual load application time within a set time period in the future. Based on the predicted load change curve and the current real-time availability margin of the unit, determine the speed pre-adjustment command, ignition advance angle pre-adjustment command, and air-fuel ratio pre-adjustment command. Before the predicted load is actually applied to the engine crankshaft, a speed pre-adjustment command is sent to the electronic governor, an ignition advance angle pre-adjustment command is sent to the engine control unit, an air-fuel ratio pre-adjustment command is sent to the electronic throttle and gas control valve, and an excitation response adjustment command is sent to the generator control unit. When the predicted load exceeds the real-time availability margin of the current units, peak shaving allocation of multiple units is performed based on the real-time availability margin of each parallel unit.

2. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: The collected control signals are compared with operating parameters and a preset load characteristic library, including: Extract the inverter frequency setpoint, programmable logic controller operating mode command, and hydraulic system pressure feedback value from the control signals; The extracted parameters are matched with the standard control signal characteristics of four typical working conditions in the load feature library: drilling rig tripping, mud pump loading, top drive start-up, and conventional steady-state operation. When the matching degree exceeds the preset threshold, the current operating condition type is determined, and the corresponding standard load change curve is called as the prediction benchmark.

3. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: Predict the load change curve and the actual load application time within a specified future time period, including: Based on the standard load change curve corresponding to the current operating condition, and combined with the rate of change and duration of the control signal, calculate the predicted load gap value within the future set time, and predict the actual time when the load is applied. The gas calorific value correction coefficient is calculated based on the real-time air-fuel ratio and gas flow rate change rate fed back by the wide-range oxygen sensor, and the load gap prediction value is corrected accordingly. The set time is determined based on the sum of the engine speed response lag period, the mechanical response lag period of the gas valve and electronic throttle, and the generator excitation response lag period.

4. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: Determine the engine speed preset command, ignition advance angle preset command, and air-fuel ratio preset command, including: Based on the predicted load gap, engine rated speed, current unit real-time availability margin, ambient intake air density correction factor, and fuel gas calorific value correction factor, the speed pre-adjustment target increment is determined according to the following relationship: ； in, To pre-adjust the target increment for the rotational speed, The load-speed coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. The engine's rated speed. This is the correction factor for the calorific value of the gas. This is the environmental intake air density correction factor; The combustion boundary margin is determined based on the distance between the current operating point and the calibrated misfire and knock boundaries. The ignition advance angle pre-adjustment target increment is determined according to the combustion boundary margin correction function. The air-fuel ratio pre-adjustment target increment is determined according to the ambient intake air density correction coefficient and the fuel gas calorific value correction coefficient.

5. The gas engine control method for oil and gas extraction environments according to claim 4, characterized in that: The combustion boundary margin is determined based on the distance between the current operating point and the calibrated misfire and detonation boundaries. The target increment for ignition advance angle is determined according to the following relationship: ； in, To pre-adjust the target increment for ignition advance angle, The load-ignition coupling coefficient is... This is the predicted load gap value. This represents the current real-time availability margin of the generating units. This is the reference ignition advance angle for the current operating condition. This is a combustion boundary margin correction function. It takes a positive value when the combustion boundary margin is greater than the preset safety threshold, and a negative value or zero when it is less than the preset safety threshold.

6. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: Sending coordinated pre-adjustment commands before the predicted load is actually applied to the engine crankshaft, including: The pre-adjustment trigger advance is determined based on the engine mechanical response lag period, the gas valve and electronic throttle mechanical response lag period, and the electrical system signal transmission lag period. At the pre-adjustment trigger advance moment when the predicted load is actually applied in front of the engine crankshaft, an air-fuel ratio pre-adjustment command is sent to the electronic throttle and gas control valve, an ignition advance angle pre-adjustment command is sent to the engine control unit, a speed pre-adjustment command is sent to the electronic governor, and an excitation response acceleration command is simultaneously sent to the generator control unit to increase the response rate of the excitation regulator by a preset ratio.

7. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: It also includes safety interlocking steps: Real-time acquisition of combustible gas concentration and engine combustion status parameters at the perimeter of the unit, including exhaust temperature, in-cylinder combustion pressure and air-fuel ratio fluctuation. When the concentration of combustible gas reaches the warning threshold, the engine load rate is limited to a preset ratio and the cooling fan speed is increased. When the concentration of combustible gas reaches the danger threshold, an orderly shutdown is carried out by first unloading and reducing the load to idle speed and then cutting off the gas supply. When the combustion state parameters exceed the knocking boundary, combustion protection actions of ignition advance angle delay and air-fuel ratio enrichment are executed; when the combustion state parameters exceed the misfire boundary, combustion recovery actions of ignition advance angle advance and air-fuel ratio enrichment are executed. The safety level switching setting has a hysteresis, which is the difference between the threshold for triggering a level increase when the concentration rises and the threshold for triggering a level decrease when the concentration falls, to avoid frequent switching of control strategies due to concentration fluctuations.

8. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: The operation of a gas turbine engine also includes a process for adjusting to sudden environmental changes, as detailed below: Real-time data collection of ambient atmospheric pressure, ambient temperature, air filter pressure difference, and gas intake pressure; When environmental parameters change abruptly relative to the start-up calibration reference value and the change exceeds the preset environmental threshold, calculate the environmental intake air density correction coefficient. Based on the gas intake pressure, the gas calorific value correction coefficient is calculated according to the real-time gas flow rate and feedback from the wide-range oxygen sensor. The real-time available margin is corrected based on the ambient intake density correction coefficient and the fuel calorific value correction coefficient to match the available margin with the abrupt changes in ambient intake conditions and fuel calorific value. The air-fuel ratio pre-adjustment command, ignition advance angle pre-adjustment command, and speed pre-adjustment target increment are determined based on the corrected real-time availability margin.

9. The gas engine control method for oil and gas extraction environments according to claim 8, characterized in that: The calculation of the ambient air intake density correction factor includes: The altitude air density correction factor is calculated based on the ratio of real-time atmospheric pressure to the starting calibration reference atmospheric pressure, and the ratio of real-time ambient temperature to the starting calibration reference ambient temperature. The air filter clogging correction factor is calculated based on the ratio of the real-time air filter differential pressure to the maximum allowable air filter differential pressure. The ambient air density correction factor is obtained by multiplying the altitude air density correction factor by the air filter blockage correction factor.

10. The gas engine control method for oil and gas extraction environments according to claim 1, characterized in that: When multiple units are connected in parallel to supply power to the same oil and gas well site power grid, each unit calculates its own gas consumption rate, real-time availability margin, and combustion boundary margin between the current operating point and the fire and detonation boundaries in real time, and interacts with each other through the controller local area network bus. Based on the differences in gas consumption rates among the units, the load of each unit is dynamically allocated according to the principle of equal incremental rate. The allocated load of each unit does not exceed the real-time available margin of the corresponding unit after reduction by the environmental intake air density correction coefficient. The combustion boundary margin between the operating point of each unit and the fire and detonation boundaries is not lower than the preset safety threshold. During the start-up and shutdown switching or load adjustment of the units, the rate of change of the load of a single unit per unit time is limited to not exceeding the preset rate threshold. When the fluctuation amplitude of the grid frequency exceeds the preset threshold, the load transfer is suspended.

Images