Single-shaft generator power station control method under host power limitation

Abstract

The invention discloses a single-shaft generator power station control method under host power limitation, and the method comprises the steps: correspondingly controlling the shaft generator rated output power through a preset relation between the shaft generator rated output power and the host rotation speed; by inputting the rotating speed of the main engine, the ship power station control system calculates the Line10 power limit value of the main engine, compares the current output power of the main engine with the Line10 power limit value of the main engine at the current rotating speed, and judges whether the residual power of the main engine is sufficient or not; the operation mode of the axle generator is controlled by judging the residual power of the main engine and the output of the axle generator; and judging whether the diesel generator needs to be started and correspondingly controlling the output load of the diesel generator according to the load condition of the shaft generator. The appropriate shaft generator operation mode can be selected according to the main engine rotating speed and the main engine load value, the shaft generator is used as many as possible to bear the ship power load, and the shaft generator can also be used when the main engine rotating speed is low.

Description

Technical Field

[0001] The present invention relates to a power station control method, in particular to a single-shaft generator power station control method under main engine power limitation, belonging to the technical field of ship power generation control. Background Art

[0002] With the development of green shipping technologies and the International Maritime Organization's increasing requirements for energy conservation and emissions reduction in the shipping industry, shaft generators have become increasingly popular with shipowners due to their significant advantages in utilizing excess main engine power and reducing maintenance costs. The main engines of ultra-large container ships are designed with a certain power margin to cope with variable sea conditions. Shaft generators can utilize this margin to cover the ship's electrical load. Under normal circumstances, shaft generators can only carry a certain amount of electrical load when the main engine has sufficient power. Continuing to use shaft generators when the main engine has insufficient power (such as during steering, in adverse sea conditions, or in other power-limited situations) will directly affect the main engine's maneuverability and have a certain impact on the ship's navigation safety.

[0003] How to maximize the operation of the shaft generator and maximize the use of the main engine power to bear the ship's electrical load in such a situation without affecting the normal operation of the main engine is a difficult problem. Therefore, it is necessary to design a reasonable shaft generator power station control method under the main engine residual power limit. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a control method for a single-shaft generator power station under host power limitation, ensuring that the shaft generator can also operate when the host power is limited, and maximize the utilization of the shaft generator when the host power margin is restored.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A control method for a single-shaft generator power station under host power limitation comprises the following steps:

[0007] S1, through the preset relationship between the shaft generator rated output power and the main engine speed, correspondingly control the shaft generator rated output power;

[0008] S2. By inputting the main engine speed, the ship power station control system calculates the main engine Line 10 power limit value, and compares the main engine's current output power with the main engine Line 10 power limit value at the current speed to determine whether the main engine's remaining power is sufficient;

[0009] S3. Control the operation mode of the shaft generator by judging the remaining power of the main engine and the output of the shaft generator;

[0010] S4. Determine whether the diesel generator needs to be started based on the load condition of the shaft generator and control the output load of the diesel generator accordingly.

[0011] Furthermore, step S1 is specifically as follows: when the main engine speed is not lower than the first speed setting value and not higher than the maximum operating speed, the rated output power of the shaft generator is controlled to be constant at the maximum value; when the main engine speed is lower than the first speed setting value and not lower than the minimum operating speed, the rated output power of the shaft generator is linearly related to the main engine speed and decreases as the main engine speed decreases; when the main engine speed is not lower than the maximum operating speed or lower than the minimum operating speed, the shaft generator stops working.

[0012] Furthermore, in step S2,

[0013] The relationship between the Line 10 power limit value of the main engine and the main engine speed can be confirmed by the following formula:

[0014] P=P0×Line10 (1)

[0015]

[0016] Among them, n is the current host speed, n o Line 10 limits the maximum host speed allowed, P is the power limit value corresponding to the current host speed, P0 is the maximum power that the host can output, and C2, C1, and C0 are constants.

[0017] Furthermore, when 0.40≤n / n0<0.60, C2=0.750, C1=0.030, C0=0.000;

[0018] When 0.60≤n / n0<0.96, C2=1.336, C1=-0.321, C0=0.000;

[0019] When 0.96≤n / n0<1.00, C2=0.000, C1=1.941, C0=-0.941.

[0020] Furthermore, step S3 is specifically as follows: when the main engine speed is not lower than the first speed setting value, the shaft generator selects the MAX operation mode or the equal sharing operation mode; when the main engine speed is lower than the first speed setting value, the shaft generator selects the equal sharing operation mode.

[0021] Furthermore, when the shaft generator selects the MAX operating mode, the ship's electrical load is borne by the shaft generator first, and the maximum load of the shaft generator at this time does not exceed 95% of the rated output power of the shaft generator. The remaining electrical load is borne by the diesel generator, and the minimum load of the diesel generator is not less than 30% of the rated output power of the diesel generator, and the maximum load of the diesel generator does not exceed 90% of the rated output power of the diesel generator;

[0022] When the shaft generator selects the equal-sharing operation mode, the ship's power load is evenly distributed to the shaft generator and the diesel generator, and the power borne by the shaft generator does not exceed 90% of the rated output power value of the shaft generator corresponding to the main engine speed at this time.

[0023] Furthermore, the step S4 is specifically as follows:

[0024] When the current load value of the main engine is not less than the Line 10 power limit value for 120 seconds, regardless of the operating mode of the shaft generator, the standby diesel generator will be controlled to start, the shaft generator operating mode will be changed to the equal sharing mode, the shaft generator load will be transferred to the diesel generator, and the main engine load limit overflow alarm will be issued;

[0025] When the shaft generator is in MAX operation mode, if the main engine speed is lower than the first speed setting value or the main engine current load value is higher than the main engine Line 10 power limit value, the shaft generator operation mode will be controlled to switch to the equalization operation mode, transferring the shaft generator load so that the on-grid generators share the ship's power load equally and start the standby diesel generator;

[0026] When the shaft generator is in the equal-sharing operation mode, if the ship power station continuously detects that the main engine speed is higher than the second speed judgment value and the main engine remaining power is greater than the first power judgment value for 120 seconds, the shaft generator will be controlled to operate in the MAX operation mode, and the diesel generator load will be transferred to the shaft generator or the diesel generator will be stopped.

[0027] Compared with the prior art, the present invention has the following advantages and effects: the present invention provides a single-shaft generator power station control method under main engine power limitation, which can select a suitable shaft generator operation mode according to the main engine speed and main engine load value, use the shaft generator as much as possible to bear the ship's power load, and can also use the shaft generator when the main engine speed is low; because the shaft generator uses the ship's main engine as a power source, its fuel utilization efficiency is better than that of a marine diesel generator, and the maintenance cost of the diesel generator is reduced; the present invention can ensure that the ship's power load is borne more by the shaft generator by monitoring the main engine speed, main engine output power and shaft generator operation load without affecting the normal operation of the ship's main engine, and can still better utilize the high-efficiency, low-emission, energy-saving and environmentally friendly shaft generator to reduce the ship's fuel consumption when the main engine speed is low, and has the characteristics of simple control, concise process, energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of a method for controlling a single-shaft generator power station under host power limitation.

[0029] Figure 2 The present invention provides a method for controlling a single-shaft generator power station under main engine power limitation, and shows a curve diagram of the relationship between the rated output power of the shaft generator and the main engine speed.

[0030] Figure 3 It is a main engine power limitation Line 10 curve diagram of a single-shaft generator power station control method under main engine power limitation of the present invention.

[0031] Figure 4 This is a ship power load distribution curve diagram in the shaft generator MAX operation mode of a single-shaft generator power station control method under main engine power limitation of the present invention. DETAILED DESCRIPTION

[0032] In order to elaborate on the technical solutions adopted by the present invention to achieve the predetermined technical purpose, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments, and the technical means or technical features in the embodiments of the present invention can be replaced without creative work. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0033] like Figure 1 As shown, a control method for a single-shaft generator power station under host power limitation of the present invention comprises the following steps:

[0034] S1. The rated output power of the shaft generator is controlled by the preset relationship between the rated output power of the shaft generator and the main engine speed.

[0035] like Figure 2 As shown, when the main engine speed is not lower than the first speed setting value of 51rpm and not higher than the maximum operating speed, the rated output power of the shaft generator is controlled to be constant at the maximum value of 4300kW; when the main engine speed is lower than the first speed setting value of 51rpm and not lower than the minimum operating speed of 20rpm, the rated output power of the shaft generator is linearly related to the main engine speed and decreases as the main engine speed decreases; when the main engine speed is not lower than the maximum operating speed of 70rpm or lower than the minimum operating speed of 20rpm, the shaft generator stops working.

[0036] S2. By inputting the main engine speed, the ship power station control system calculates the main engine Line 10 power limit value, and compares the main engine's current output power with the main engine Line 10 power limit value at the current speed to determine whether the main engine's remaining power is sufficient.

[0037] The relationship between the Line 10 power limit value of the main engine and the main engine speed can be confirmed by the following formula:

[0038] P=P0×Line10 (1)

[0039]

[0040] Among them, n is the current host speed, n o Line 10 limits the maximum host speed allowed, which is 70 rpm in this embodiment. It is the power limit value corresponding to the current host speed. P0 is the maximum power that the host can output. C2, C1 and C0 are constants.

[0041] When 0.40≤n / n0<0.60, C2=0.750, C1=0.030, C0=0.000;

[0042] When 0.60≤n / n0<0.96, C2=1.336, C1=-0.321, C0=0.000;

[0043] When 0.96≤n / n0<1.00, C2=0.000, C1=1.941, C0=-0.941.

[0044] like Figure 3As shown in the figure, the Line 10 value of the main engine changes in three stages as the main engine speed increases. Overall, the Line 10 value is positively correlated with the main engine speed. When the main engine speed is between 67.2 rpm and 70 rpm, the Line 10 value changes linearly with the main engine speed. When the main engine speed is between 28 rpm and 42 rpm and 42 rpm and 67.2 rpm, the Line 10 value of the main engine changes quadratically with the main engine speed. Regardless of the main engine speed, there is a unique corresponding Line 10 value.

[0045] S3. Control the operation mode of the shaft generator by judging the remaining power of the main engine and the output of the shaft generator.

[0046] When the main engine speed is not lower than the first speed setting value of 51 rpm, the shaft generator selects the MAX operation mode or the equal sharing operation mode; when the main engine speed is lower than the first speed setting value of 51 rpm, the shaft generator selects the equal sharing operation mode.

[0047] When the shaft generator selects the MAX operating mode, the ship's electrical load is borne by the shaft generator first, and the maximum load of the shaft generator at this time does not exceed 95% of the rated output power of the shaft generator, that is, 4085kW. The remaining electrical load is borne by the diesel generator, and the minimum load of the diesel generator is not less than 30% of the rated output power of the diesel generator, and the maximum load of the diesel generator does not exceed 90% of the rated output power of the diesel generator.

[0048] When the shaft generator selects the equal-sharing operation mode, the ship's power load is evenly distributed to the shaft generator and the diesel generator, and the power borne by the shaft generator does not exceed 90% of the rated output power value of the shaft generator corresponding to the main engine speed at this time.

[0049] like Figure 4 As shown, since the minimum load borne by a ship's diesel generators is 1290kW (4300kW * 30%), when the shaft generators are in MAX mode and the total ship load is greater than 4085kW but less than 5375kW, the diesel generators carry 1290kW of the load, with the shaft generators carrying the remainder. When the total ship load exceeds 5375kW, the shaft generators carry 4085kW of the load, with the diesel generators carrying the remainder. Furthermore, the diesel generator overload threshold is 3870kW. When the total ship load exceeds 7955kW, the remaining load after the shaft generators are evenly distributed among multiple diesel generators. This means the shaft generators carry 4080kW of the load, with the remaining load evenly distributed among the diesel generators.

[0050] S4. Determine whether the diesel generator needs to be started based on the load condition of the shaft generator and control the output load of the diesel generator accordingly.

[0051] When the main engine speed is less than 51rpm, the shaft generator can only be in the equal-sharing operation mode. When the ship power station continuously monitors that the main engine load is not less than the main engine Line 10 limit value for 120s, it will control the standby generator to start, further sharing the shaft generator load to reduce the main engine load.

[0052] When the current load value of the main engine is not less than the Line 10 power limit value of the main engine for 120 seconds, regardless of the operating mode of the shaft generator, the standby diesel generator will be controlled to start, the operating mode of the shaft generator will be changed to the equal sharing mode, the load of the shaft generator will be transferred to the diesel generator, and the main engine load limit overflow alarm will be issued.

[0053] When the shaft generator is in MAX operation mode, if the main engine speed is lower than the first speed setting value of 51rpm or the current load value of the main engine is higher than the main engine Line 10 power limit value, the shaft generator operation mode will be controlled to switch to equal sharing operation mode, the shaft generator load will be transferred, and the shaft generator and the diesel generator will share the ship's power load equally, so that the grid generator will share the ship's power load equally and start the standby diesel generator.

[0054] When the shaft generator is in the equal-sharing operation mode, if the ship power station continuously detects that the main engine speed is higher than the second speed judgment value of 54rpm and the main engine residual power is greater than the first power judgment value of 6500kW for 120s, the shaft generator will be controlled to operate in the MAX operation mode, and the diesel generator load will be transferred to the shaft generator, so that the ship's power load is borne by the shaft generator as much as possible. Figure 4 Determine whether to start the diesel generator and the power load the diesel generator must bear. The remaining power of the main engine is the Line 10 power limit of the main engine minus the current load value of the main engine. This value indicates the power value that the main engine can still bear at the current speed.

[0055] The second speed judgment value for the main engine is greater than the first speed setting value, and the first power judgment value is greater than the maximum rated output power of the shaft generator. This is to prevent instantaneous load or speed fluctuations in the main engine from causing repeated switching of the shaft generator operating mode. Both the second speed judgment value and the first power judgment value can be adjusted within the ship's power station control system to achieve better control of the shaft generator operating mode. Similarly, the 120-second continuous monitoring before switching the shaft generator operating mode to MAX mode is also to ensure that the main engine load is indeed sufficient. This delay can also be adjusted within the ship's power station control system.

[0056] The present invention provides a single-shaft generator power station control method under main engine power limitation. The method can select a suitable shaft generator operation mode according to the main engine speed and the main engine load value, use the shaft generator as much as possible to bear the ship's power load, and can also use the shaft generator when the main engine speed is low. Since the shaft generator uses the ship's main engine as a power source, its fuel utilization efficiency is better than that of a marine diesel generator, and the maintenance cost of the diesel generator is reduced. The present invention can ensure that the ship's power load is borne more by the shaft generator by monitoring the main engine speed, main engine output power and shaft generator operation load without affecting the normal operation of the ship's main engine, and can still better utilize the high-efficiency, low-emission, energy-saving and environmentally friendly shaft generator to reduce the ship's fuel consumption when the main engine speed is low. It has the characteristics of simple control, concise process, energy saving and emission reduction.

[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A control method for a single-shaft generator power station under host power limitation, characterized in that The following steps are involved: S1, through the preset relationship between the shaft generator rated output power and the main engine speed, correspondingly control the shaft generator rated output power; S2. By inputting the main engine speed, the ship power station control system calculates the main engine Line 10 power limit value, and compares the main engine's current output power with the main engine Line 10 power limit value at the current speed to determine whether the main engine's remaining power is sufficient; S3. Control the operation mode of the shaft generator by judging the remaining power of the main engine and the output of the shaft generator; S4. Determine whether the diesel generator needs to be started based on the load condition of the shaft generator and control the output load of the diesel generator accordingly.

2. The method for controlling a single-shaft generator power station under host power limitation according to claim 1, characterized in that: The step S1 specifically includes: when the main engine speed is not lower than the first speed setting value and not higher than the maximum operating speed, controlling the rated output power of the shaft generator to be constant at the maximum value; when the main engine speed is lower than the first speed setting value and not lower than the minimum operating speed, the rated output power of the shaft generator is linearly related to the main engine speed and decreases as the main engine speed decreases; when the main engine speed is not lower than the maximum operating speed or lower than the minimum operating speed, the shaft generator stops working.

3. The method for controlling a single-shaft generator power station under host power limitation according to claim 1, characterized in that: In the step S2, The relationship between the Line 10 power limit value of the main engine and the main engine speed can be confirmed by the following formula: P=P0×Line10 (1) Among them, n is the current host speed, n o Line 10 limits the maximum host speed allowed, P is the power limit value corresponding to the current host speed, P0 is the maximum power that the host can output, and C2, C1, and C0 are constants.

4. The method for controlling a single-shaft generator power station under host power limitation according to claim 3, characterized in that: When 0.40≤n / n0<0.60, C2=0.750, C1=0.030, C0=0.000; When 0.60≤n / n0<0.96, C2=1.336, C1=-0.321, C0=0.000; When 0.96≤n / n0<1.00, C2=0.000, C1=1.941, C0=-0.

941.

5. The method for controlling a single-shaft generator power station under host power limitation according to claim 1, characterized in that: The step S3 is specifically as follows: when the main engine speed is not lower than the first speed setting value, the shaft generator selects the MAX operation mode or the equal sharing operation mode; when the main engine speed is lower than the first speed setting value, the shaft generator selects the equal sharing operation mode.

6. The method for controlling a single-shaft generator power station under host power limitation according to claim 5, characterized in that: When the shaft generator is in MAX operation mode, the ship's electrical load is borne by the shaft generator first, and the maximum load of the shaft generator does not exceed 95% of the rated output power of the shaft generator. The remaining electrical load is borne by the diesel generator, and the minimum load of the diesel generator is not less than 30% of the rated output power of the diesel generator, and the maximum load of the diesel generator does not exceed 90% of the rated output power of the diesel generator; When the shaft generator selects the equal-sharing operation mode, the ship's power load is evenly distributed to the shaft generator and the diesel generator, and the power borne by the shaft generator does not exceed 90% of the rated output power value of the shaft generator corresponding to the main engine speed at this time.

7. The method for controlling a single-shaft generator power station under host power limitation according to claim 1, characterized in that: The step S4 is specifically as follows: When the current load value of the main engine is not less than the Line 10 power limit value for 120 seconds, regardless of the operating mode of the shaft generator, the standby diesel generator will be controlled to start, the shaft generator operating mode will be changed to the equal sharing mode, the shaft generator load will be transferred to the diesel generator, and the main engine load limit overflow alarm will be issued; When the shaft generator is in MAX operation mode, if the main engine speed is lower than the first speed setting value or the main engine current load value is higher than the main engine Line 10 power limit value, the shaft generator operation mode will be controlled to switch to the equalization operation mode, transferring the shaft generator load so that the on-grid generators share the ship's power load equally and start the standby diesel generator; When the shaft generator is in the equal-sharing operation mode, if the ship power station continuously detects that the main engine speed is higher than the second speed judgment value and the main engine remaining power is greater than the first power judgment value for 120 seconds, the shaft generator will be controlled to operate in the MAX operation mode, and the diesel generator load will be transferred to the shaft generator or the diesel generator will be stopped.

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