Design method of system for additionally installing axle generator on operating ship

Abstract

The invention relates to a method for designing a system for adding an axle generator to an operating ship, which comprises the following steps of: 1, carrying out ship characteristic analysis, demand matching and original ship parameter acquisition, namely carrying out original ship 3D (three-dimensional) scanning and surveying and mapping, collecting original ship mechanical and electrical parameters, and determining the capacity and rotating speed range of the axle generator according to an electrical load and the residual power of a main engine; 2, system design, including shaft system dynamic analysis, power control system control logic matching, short-circuit current calculation and selective protection analysis; 3, designing equipment, including model selection and parameter determination of a shaft motor, a frequency converter and an isolation transformer; 4, onshore system joint debugging tests including a single machine performance test and a parallel operation function test; and 5, real ship installation, debugging and inspection, including equipment installation, insulation detection, monitoring alarm function test and trial flight inspection. According to the invention, the design flow of the added shaft-driven motor system is standardized, the stability of the shaft-driven motor system and the reliability of equipment are improved, and the operation risk of a real ship is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship power system modification, in particular to a design method of installing an axle generator system on an operating ship, which is suitable for modifying an operating ship to realize energy saving and consumption reduction and meet the carbon emission limitation of International Maritime Organization (IMO) through installing an axle generator. BACKGROUND

[0002] With the strict limitation of International Maritime Organization (IMO) on ship carbon emission (EEXI, CII index) and the realistic pressure of ship fuel cost accounting for 50-60% of operating cost, the axle generator technology is promoted to be a key path for energy saving and consumption reduction. The technology can reduce auxiliary machine operation time through generating power by using surplus power of the main engine, realize annual fuel saving of 10-15%, and reduce oil consumption and maintenance cost, which has significant economic and environmental benefits. It has become an important research direction and application hotspot for large ship modification and new ship type.

[0003] At present, the axle generator system for new ships has formed relatively perfect specification standards and design criteria, while the specification standards for installing the axle generator system on operating ships are vacant, and the design standards and installation quality are uneven, which leads to the risk of mechanical structure and electrical system after installation.

[0004] In the prior art, the patent document (CN104978446A) discloses a ship integrated power system integrated design method, but it is aimed at the overall design of the power system of a new ship, does not involve the special needs of installing the axle generator on an operating ship (such as original ship parameter collection, 3D scanning, non-extraction shaft installation), and does not consider the compatibility of shafting dynamic analysis and the original ship power grid; the patent document (CN105539722A) discloses a method for evaluating the installation skills of ship main engine and shafting, which focuses on the evaluation of the installation skills of the main engine and shafting, only involves the measurement and adjustment of installation parameters, does not involve the design process, power control logic and test verification of the axle generator system, and cannot solve the systematic problems of installing on an operating ship.

[0005] Therefore, there is an urgent need for a design method for installing an axle generator system on an operating ship, which can improve the economy, reliability and environmental protection of the ship through standardized process, adaptive system, equipment selection and optimization control strategy. The technology popularization needs to combine the international regulation dynamics and ship type characteristics, continuously optimize the system compatibility and operation convenience, and provide core support for the low-carbon transformation of the shipping industry. SUMMARY

[0006] The purpose of the present application aims to solve the demand of installing shaft generator on operating ships to meet the restrictions of carbon emissions (EEXI, CII index), and provides a design method of installing shaft generator system on operating ships, which analyzes the characteristics of operating ships and matches the demand, combines with 3D scanning and mapping of real ships, carries out design of shaft generator system selection and arrangement, power electronics and control system, shafting dynamic characteristic analysis, and carries out system verification through land system debugging test. The design method suitable for installing shaft generator on operating ships is proposed, which provides a new design idea for standardization of installing shaft generator on operating ships.

[0007] To achieve the above purpose, the technical scheme of the present application is: a design method of installing shaft generator system on operating ships, the system comprising a half-type shaft generator, a frequency conversion cabinet, an isolation transformer, a star point switch cabinet, a shaft generator access screen and a UPS uninterrupted power supply, the method comprising the following steps:

[0008] Step one, ship characteristic analysis and demand matching and original ship parameter collection, including carrying out 3D scanning and mapping of the original ship, collecting original ship mechanical and electrical parameters, determining the shaft generator capacity and speed range according to the electrical load and the remaining power of the main engine;

[0009] Step two, system design, including shafting dynamic analysis, power control system control logic matching, short-circuit current calculation and selective protection analysis of the installed shaft generator;

[0010] Step three, equipment design, including type selection and parameter determination of the shaft generator, frequency converter and isolation transformer;

[0011] Step four, land system debugging test, including single machine performance test and parallel operation function test;

[0012] Step five, real ship installation, debugging and inspection, including equipment installation, insulation detection, monitoring and alarm function test and trial inspection.

[0013] Further, in step one, the range of 3D scanning and mapping of the original ship includes the engine room, shafting, control room and access port; the original mechanical parameters include the main engine power / speed, shafting size; the original electrical parameters include auxiliary machine parameters, electrical system diagram and power load calculation book.

[0014] Further, in step one, the shaft generator capacity is selected according to the total electrical load of the ship navigation working condition, and the load coefficient is 0.7-0.85; the shaft generator power generation speed range is 0.7-0.9 times of the main engine continuous service power speed.

[0015] Further, in step two, the shafting dynamic analysis includes torsional vibration, longitudinal vibration and alignment calculation, specifically: torsional vibration: the resonance speed range is outside the shaft generator power generation speed range, and the combined amplitude at the generator rotor under rated working condition is not greater than 3.5° electric angle; longitudinal vibration: the longitudinal vibration amplitude is not greater than the allowable amplitude; alignment: all bearings are under positive and negative load under static state, the bearing load is not less than 20% of the total weight of all adjacent spans, and is not greater than the specified value or the manufacturer's specified value; the above calculations all meet the requirements of the classification society.

[0016] Further, in step two, the power control system control logic matching includes: the coordinated control of the shaft generator in the ship power station involves power distribution, frequency / voltage regulation and multi-working condition switching, solves the influence of main engine speed fluctuation on power grid stability, and cooperates with auxiliary generator set; the frequency of the shaft generator output is stabilized through the frequency conversion cabinet, the differential characteristic matching with the diesel generator is realized, and the power sharing and reactive power compensation when grid connected are ensured; the heavy load inquiry standby machine scheme is adopted for the original ship high-power equipment, and the impact of large current on the shaft island mode is reduced.

[0017] Further, in step two, the short-circuit current calculation and selective protection analysis includes: considering the short-circuit current calculation when one shaft generator and one generator are running in parallel under navigation working condition; checking the withstand capacity of the original distribution board switch and the newly added switch to meet the requirements of the classification society.

[0018] Further, in step three, the shaft generator is an upper and lower half type permanent magnet or electrically excited synchronous generator added to the non-extraction shaft, and the rated output power is determined according to the system efficiency of 0.92-0.93, and the no-load back electromotive force of the highest speed of the generator is not more than 820V.

[0019] Further, in step three, the frequency converter is AFE active front-end frequency converter or DFE diode front-end frequency converter, which adopts water-cooled type, the machine side module considers 1.1 times overload margin, and the network side module has short-circuit current support capacity of 2 times rated current 2s.

[0020] Further, in step four, the land-based system joint debugging test includes: ship-mounted equipment: the motor, frequency converter and transformer are sent to the land-based test site for installation and debugging; single machine performance test: 25%-50%-75%-100% load test, steady-state voltage fluctuation rate ±6%-10%, frequency fluctuation rate ±5%; sudden increase and sudden decrease test: 0-33%-66%-100% and 100%-0 load test, transient voltage fluctuation rate ±20%, recovery time 1.5s, frequency fluctuation rate ±10%, recovery time 5s; parallel function test: parallel, load transfer test is carried out by manual and automatic combination of the distribution board, to ensure power sharing and grid stability.

[0021] Further, in step five, the real ship installation includes: hoisting the equipment to the installation position, welding the base of the shaft motor and the frequency converter to the ship body; fixing the split type expansion sleeve flange on the original ship shaft, rotating the lower half motor rotor to the lower side after connecting it with the expansion sleeve flange, installing the other half rotor, adjusting the anchor bolts to make the axial clearances of the front and rear ends of the motor consistent, and aligning the stator and rotor; installing the jack according to the calculation book to ensure that the jacking force is perpendicular to the shaft center line, and the deviation between the measured bearing load and the theoretical value is within ±20%; the real ship debugging includes insulation detection: the insulation resistance is not less than 1MΩ, monitoring alarm function test and shaft switch cabinet interlocking and protection function test; the trial test includes: shaft generator island operation test: the main engine runs at a speed range of 68-84 rpm, and runs at 100% load for 1 hour respectively, and records the voltage, current, frequency and power factor parameters; diesel generator and shaft generator manual parallel operation and splitting test to ensure smooth load transfer; shaft generator fault automatic standby generator test and large load start-stop test to verify the system stability.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. Targeted adaptation to operating ships: through 3D scanning and original ship parameter acquisition, the spatial limitations and equipment characteristics of the operating ship are accurately matched, solving the problem that the new ship design method is not suitable for the modification scene;

[0024] 2. Improve system stability: shafting dynamic analysis (torsional vibration, longitudinal vibration, centering) ensures the safety of the shafting, PMS control logic matching solves the influence of main engine speed fluctuation on the power grid, and short-circuit current calculation avoids equipment damage;

[0025] 3. Reduce installation difficulty: split type shaft motor realizes non-axle extraction installation, reduces the downtime of the ship, and reduces the modification cost;

[0026] 4. Shorten the verification period: on-land system debugging finds problems in advance, reduces the risk and time of sea trial, and reduces the cost of trial test;

[0027] 5. Meet the requirements of environmental protection and economy: through the shaft generator, the surplus power of the main engine is utilized to save fuel, meet the IMO carbon emission limit, and improve the operation efficiency.

[0028] In summary, through the design and analysis of the shaft generator system, the design elements of the system and the equipment, the system matching, the control strategy, the equipment selection, the calculation analysis, the on-land debugging and the real ship installation and debugging process are clarified. Further, the design process of the shaft generator system is further standardized, the stability of the shaft generator system and the reliability of the equipment are improved, and the risk of real ship operation is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The low-speed shaft generator system effect diagram of the operating ship of the shaft generator system design method for the operating ship of the present application;

[0030] Figure 2 Low-speed shaft generator system single-line diagram of the method for designing the shaft generator system added to the operating ship of the application;

[0031] Figure 3 Low-speed shaft generator system design flowchart of the method for designing the shaft generator system added to the operating ship of the application;

[0032] Figure 4 Half-split permanent magnet motor installation schematic diagram of the method for designing the shaft generator system added to the operating ship of the application;

[0033] Figure 5 Half-split permanent magnet motor structure schematic diagram of the method for designing the shaft generator system added to the operating ship of the application;

[0034] Figure 6 Land joint debugging schematic diagram of the method for designing the shaft generator system added to the operating ship of the application;

[0035] In the figure: 1-half-split shaft generator, 2-frequency conversion cabinet, 3-isolation transformer, 4-star point switch cabinet, 5-shaft generator access screen, 6-UPS uninterrupted power supply. DETAILED DESCRIPTION

[0036] The application will be further described below by means of a specific embodiment in combination with the accompanying drawings of the embodiment.

[0037] The method for designing the shaft generator system added to the operating ship of the application, the system composition is as shown in Figure 1 and Figure 2 , comprising: half-split shaft generator 1, frequency conversion cabinet 2, isolation transformer 3, star point switch cabinet 4, shaft generator access screen 5, UPS uninterrupted power supply 6. The steps of the design method are as follows:

[0038] Step one, ship characteristic analysis and demand matching and original ship parameter collection

[0039] Carry out original ship 3D scanning and mapping (machinery room, shafting, centralized control room, access port, etc.);

[0040] Original ship mechanical part: main engine parameter (power / rotational speed), shafting size, etc. Parameter collection;

[0041] Original ship electrical part: auxiliary machine parameter, electrical system diagram, power load calculation book, etc. Collection;

[0042] The shaft generator capacity is selected according to the power load demand of the ship and the remaining power of the main engine. Generally, the total power load in the navigation condition is calculated according to the power load calculation book, and the load coefficient is considered to be 0.7-0.85. The power of the original single generator set of the ship can also be referred to. The rotating speed range of the shaft generator can be selected according to 0.7-0.9 of the continuous service power rotating speed (CSR) of the main engine.

[0043] Step two, system design

[0044] (I) Shafting dynamic analysis

[0045] It includes torsional vibration, longitudinal vibration and alignment calculation. The calculation and analysis are carried out according to the moment of inertia of the shaft generator and the arrangement position.

[0046] Torsional vibration: the resonance rotating speed interval of the calculation result is outside the rotating speed range of the shaft generator; under the rated condition, the combined amplitude at the generator rotor shall not be greater than 3.5° (electrical angle);

[0047] Longitudinal vibration: the longitudinal vibration amplitude of the calculation result does not exceed the allowable amplitude:

[0048] Alignment: under static state, all bearings shall be under positive load, i.e. no bearing unloading phenomenon shall occur. The bearing load shall generally be not less than 20% of the total weight of all the weights between the adjacent two spans; the bearing load shall generally not exceed the specified value or the value specified by the manufacturer:

[0049] The above calculation shall meet the corresponding requirements of the classification society.

[0050] (II) Control logic matching of power control system (PMS)

[0051] The coordinated control of the shaft generator in the ship power station involves power distribution, frequency / voltage regulation and multi-condition switching. The core is to solve the influence of the main engine rotating speed fluctuation on the stability of the power grid, and to work cooperatively with the auxiliary generator set (such as the diesel generator).

[0052] (1) The input working parameters (such as power and rotating speed) of the shaft generator are subject to the working condition of the propeller of the main engine, and the output working parameters (such as voltage, current and frequency) shall meet the requirements of the power consuming equipment.

[0053] The output frequency of the shaft generator is proportional to the rotating speed of the main engine. The change of the rotating speed of the main engine in the fixed pitch propeller ship will lead to frequency deviation and voltage fluctuation, which needs to be stabilized by the frequency conversion cabinet.

[0054] The differential characteristic matching with the diesel generator is realized through the frequency conversion cabinet to ensure the power sharing and reactive power compensation when connected to the grid.

[0055] (2) For the high-power equipment (main engine oil pump, main air compressor) of the original ship direct start / star delta start, the heavy load interrogation start standby engine (diesel generator set) scheme is adopted to reduce the impact of high current on the shaft generator island mode and avoid power outage;

[0056] (III) Short-circuit current calculation and selective protection analysis for the addition of a shaft-driven generator

[0057] (1) Generally, the short-circuit current is calculated when a single shaft generator and a single generator are running in parallel under navigation conditions.

[0058] (2) Short-circuit current calculation: Verify whether the switches on the original distribution board meet the requirements, and calculate the newly added switches. Short-circuit calculation and selective protection meet the classification society requirements.

[0059] Step 3: Equipment Design

[0060] (I) Shaft-driven motor

[0061] Type: No shaft removal installation required; select a split-type permanent magnet or electrically excited synchronous generator for easy on-site installation. See attachment. Figure 3 .

[0062] Rated output power: Based on the determined power generation from the shaft-driven system to the AC grid, and taking a system efficiency of 0.92 to 0.93, determine the rated output power of the shaft-driven motor;

[0063] No-load back EMF: The no-load back EMF at the highest generating speed does not exceed 820V.

[0064] (II) Frequency Converter

[0065] Type: AFE (Active Front-End Inverter) or DFE (Diode Front-End Inverter), water-cooled;

[0066] Based on the motor output power / current / voltage within the speed range, configure the machine-side and grid-side modules. The machine-side module is designed with overload margin (1.1 times), and the grid-side module is designed with short-circuit current support capability (2 times rated current for 2s).

[0067] (III) Isolation Transformer

[0068] Considering a power factor of 0.8 and overload, select the rated capacity. Select the transformation ratio based on the inverter output and the grid voltage.

[0069] Step 4: Land-based system integration and testing, including single-unit performance testing and parallel operation function testing;

[0070] Step 5: Onboard installation, commissioning, and inspection, including equipment installation, insulation testing, monitoring and alarm function testing, and sea trial inspection.

[0071] Example:

[0072] As Figures 1 to 6 shown, the embodiment of the present application provides a kind of installation shaft motor system design method, comprising:

[0073] Equipment composition: half type shaft motor (1), frequency conversion cabinet (2), isolation transformer (3), star point switch cabinet (4), shaft launch access screen (5), UPS (6).

[0074] Main engine driving shaft is connected to star point switch cabinet and frequency conversion cabinet by the electricity of half type shaft motor, then is connected to shaft launch access screen by isolation transformer, and UPS provides control power supply of frequency conversion cabinet and shaft launch access screen.

[0075] In addition to the above embodiment, the design method of the present application is as follows:

[0076] Step one: ship characteristic analysis and demand matching and original ship parameter acquisition

[0077] Specifically, the original ship power system is configured with 3 600KW diesel generator sets and 1 120KW emergency generator set for 440V / 3 phase / 60HZ alternating current power grid. The power load calculation book lists 6 kinds of operating conditions (sea navigation, sea ballast water replacement, entering and leaving port, loading and unloading, berthing, emergency navigation), comprehensive analysis, shaft generator system is mainly applied in sea navigation condition, the load of sea navigation condition is about 494KW, the load coefficient 0.75 determines the shaft generator to the alternating current network side power 700KW,

[0078] Carry out original ship 3D scanning and surveying (machinery room, shafting, control room, access port, etc.), obtain the actual shaft diameter of intermediate shaft, according to the space and external dimensions of access port opening, original ship distribution board, machinery room and control room. Determine the maximum external dimensions of half type shaft motor, shaft launch access screen, frequency conversion cabinet, isolation transformer, star point switch cabinet and other equipment.

[0079] Step two: system design

[0080] Shafting dynamic analysis: including torsional vibration, longitudinal vibration, centering calculation. According to the moment of inertia of shaft motor and arrangement position, calculation and analysis are carried out.

[0081] Torsional vibration: shaft generator system is mainly applied in main engine normal operating condition, other single cylinder flameout and other special conditions mainly evaluate resonance speed and torsional vibration stress. The resonance speed range of this project is 40-48.5rpm, which is outside the shaft motor generation speed range of 68~84rpm. At the same time, the torsional vibration allowable stress of thrust shaft, intermediate shaft and propeller shaft should not exceed the specified value. In rated condition, the combined amplitude at the generator rotor is about 0.008 rad, and the electric angle is 0.14°, which is not greater than the specification requirement of 3.5°;

[0082] Longitudinal vibration: the calculated amplitude is not more than the allowable amplitude: the axial displacement value is not more than 3.00mm;

[0083] Centering: under static conditions, all bearings should be under positive load, i.e. no bearing unloading should occur. The bearing load should generally be not less than 20% of the total weight of all loads between the two adjacent spans; the bearing load should generally be not more than the specified value or the value specified by the manufacturer:

[0084] The above calculations should meet the corresponding requirements of the classification society.

[0085] Short-circuit current calculation and selective curve analysis: for the navigation condition, the short-circuit current calculation when a single shaft generator is connected with a generator. According to the IEC60909-0 4.3.1.1 formula, the maximum short-circuit current fed by the frequency converter is I"k=1.745KA, and R / X is taken as 0.1 to calculate that the maximum short-circuit current fed by the shaft generator is Ip=3.642KA. For the ballast condition, the short-circuit current calculation when a single shaft generator is connected with two generators. According to the IEC60909-0 4.3.1.1 formula, the maximum short-circuit current fed by the frequency converter is I"k=1.745KA, and R / X is taken as 0.1 to calculate that the maximum short-circuit current fed by the shaft generator is Ip=3.642KA.

[0086] The short-circuit current calculation results are all less than the maximum short-circuit current under the original ship's working condition, so the switches on the original distribution board all meet the requirements, and only the newly added switches are calculated.

[0087] Step three: equipment design

[0088] The rated output power of the shaft generator is determined as 750KW considering the 0.93 efficiency; the original ship's main engine type is MAN-B&W 5S60ME-C8.2Tier II, CSR: 8197kW x 93.7rpm, according to the (70%~90%) main engine CSR speed, the rated power output speed range of the motor of the project is selected as 68~84rpm. The project is a low-voltage variable frequency power generation application, and the final rated design parameters of the shaft generator are determined as 750KW / 68~84rpm, 690V, IC37W (water jacket cooling); according to the requirement of not extracting the shaft, the motor type is a half-type permanent magnet motor. Motor

[0089] The frequency converter adopts AFE, water cooling type, allows the maximum back electromotive force of the motor to be 808V@84rpm, the machine side module is selected to meet the continuous rated current of the motor 681A, the short-circuit support current of the grid side module meets 2s, has the functions of grid sampling and synchronization, and can ensure that the phase, frequency and voltage of the frequency converter output are synchronized with the grid.

[0090] According to the requirements of the power / voltage 700KW / 450V / 60HZ, power factor 0.8, the frequency converter output 660V, the selection capacity 880KVA, voltage ratio 660 / 450 isolation transformer.

[0091] Step four: land system debugging test

[0092] Shipment equipment (motor, frequency converter, transformer) and so on send to land test site, installation and debugging. Single machine performance (load test, sudden increase and sudden decrease test), parallel operation function (manual, automatic combination distribution board parallel operation, load transfer) test.

[0093] Load test: 25%-50%-75%-100% load, steady-state fluctuation rate: voltage (%) +6-10, frequency (%) ±5;

[0094] Sudden increase and sudden decrease test: 0-33%-66%-100% load, 100%-0 load. Transient fluctuation rate: voltage (%) ±20, recovery time (s) 1.5s, frequency (%) ±10, recovery time (s) 5s;

[0095] Through the debugging, the test that cannot be carried out in the terminal stage can be carried out on the entire shaft power generation system in the land debugging stage, the problems found are corrected in advance, the safety of sea trial is significantly improved, the sea trial time is shortened, and the sea trial fund expenditure is reduced.

[0096] Step five: real ship installation, debugging and inspection

[0097] Installation:

[0098] Equipment hoisting to installation position. The base of shaft generator and frequency converter is welded with the ship body;

[0099] The half expansion sleeve flange is fixed according to the positioning of the motor on the original ship shaft, the lower half motor rotor is connected with the expansion sleeve flange, the rotor is turned to the lower side by the disc shaft, the other half rotor is installed, the foot bolts are adjusted to make the axial clearance of the front and rear ends of the motor consistent, and the stator and rotor are aligned;

[0100] The jack is installed according to the specified position in the calculation book, and it is ensured that the jacking force is perpendicular to the shaft center line. The measured bearing load obtained by the rising and falling curves of the jacking is compared with the theoretical bearing load, which should be within the theoretical allowable range (±20%). After the inspection of the calculation book, the rotor air gap of the shaft generator is measured, and the allowable deviation is ≤10%;

[0101] The fixation of the motor is completed. The cable wiring of the motor, star point cabinet, frequency converter, shaft generator screen and other equipment is completed. The installation of the external cold water pipeline of the frequency converter and shaft generator is completed.

[0102] Debugging:

[0103] Insulation detection: measure the insulation resistance of the motor and transformer to ground with megohmmeter, generally the insulation resistance is not less than 1MΩ;

[0104] Monitoring alarm function test: verify the alarm function of the motor, frequency converter, transformer and other equipment;

[0105] Shaft switchgear function test: interlock function and protection function test;

[0106] Trial report:

[0107] Shaft generator island power generation operation: the main engine runs in the range of 68-84 rpm, among which 68 rpm, 75 rpm and 84 rpm run at 100% load for 1 hour, respectively, record parameters such as voltage, current, frequency and power factor, and monitor whether there is alarm and abnormal operation;

[0108] Diesel generator and shaft generator manual parallel operation and splitting: when a diesel generator is on the network, start the shaft generator, operate the shaft generator synchronization and grid closing switch on the control screen, then transfer the load to the shaft generator by operating the diesel generator speed switch, cut off the diesel generator main switch and stop the diesel generator. When the shaft generator is on the network, start a diesel generator, operate the diesel generator synchronization and grid closing switch on the main distribution board synchronization screen, then transfer the load to the diesel generator by operating the power reduction switch on the shaft generator switch cabinet, cut off the shaft generator main switch and operate the frequency converter to stop the diesel generator.

[0109] Shaft generator fault automatic standby machine: when the frequency of the power station changes beyond the limit value, a designated standby main generator will be automatically started to replace the shaft generator to supply power to the power grid.

[0110] Large load start-stop test: when the shaft generator supplies power, start and stop a large load on the ship to test the shaft generator island mode, which can maintain safe operation within the safe range.

[0111] In summary, the present application solves the key technical problems of installing shaft generators on operating ships through standardized design processes, improves system stability and economy, and has significant practical value.

Claims

1. A method for designing a system of operating a ship with an add-on shaft generator, the system comprising a split-half shaft generator, a frequency conversion cabinet, an isolation transformer, a star point switch cabinet, a shaft generator access screen, a UPS uninterruptible power supply, characterized in that, The method comprises the following steps: Step one, ship characteristic analysis and demand matching and original ship parameter collection, including developing original ship 3D scanning and mapping, collecting original ship mechanical and electrical parameters, determining shaft generator capacity and rotating speed range according to power load and main engine residual power; Step two, system design, including shafting dynamic analysis, power control system control logic matching, short circuit current calculation of shaft-mounted generator and selective protection analysis; Step three, equipment design, including selection and parameter determination of shaft-mounted generator, frequency converter and isolation transformer; Step four, land-based system commissioning test, including single machine performance test and parallel operation function test; Step five, real ship installation, commissioning and inspection, including equipment installation, insulation detection, monitoring and alarm function test and trial navigation inspection.

2. The method of designing a system for retrofitting a marine vessel with an axle generator system according to claim 1, wherein, In step one, the range of original ship 3D scanning and mapping includes engine room, shafting, control room and access hatch; original ship mechanical parameters include main engine power / rotating speed, shafting size; the original ship electrical parameters include auxiliary machine parameters, electrical system diagram and power load calculation book.

3. The method of designing a system for retrofitting a marine vessel with an axle generator system according to claim 1, wherein, In step one, the shaft generator capacity is selected according to the total power load under ship navigation working condition, and the load coefficient is 0.7-0.85; the shaft generator power generation rotating speed range is 0.7-0.9 times of the main engine continuous service power rotating speed.

4. The method of designing a retrofitting shaft generator system for an operating ship according to claim 1, wherein In step two, the shafting dynamic analysis includes torsional vibration, longitudinal vibration and centering calculation, specifically: torsional vibration: the resonance rotating speed interval is outside the shaft generator power generation rotating speed range, and the combined amplitude at the generator rotor under the rated working condition is not greater than 3.5° electric angle; longitudinal vibration: the longitudinal vibration amplitude is not greater than the allowable amplitude; centering: all bearings are under positive and negative load under static state, the bearing load is not less than 20% of the total weight between adjacent two spans, and is not greater than the specified value or the manufacturer's specified value; the above calculations all meet the requirements of the classification society.

5. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step two, the power control system control logic matching includes: the coordinated control of the shaft generator in the ship power station involves power distribution, frequency / voltage regulation and multi-working condition switching, solves the influence of main engine rotating speed fluctuation on the stability of the power grid, and cooperates with the auxiliary generator set; the frequency converter cabinet is used to stabilize the shaft generator output frequency, realizes the matching of the differential characteristics with the diesel generator, ensures the power sharing and reactive power compensation when parallel operation; the heavy load inquiry standby machine scheme is adopted for the original high-power equipment, so as to reduce the impact of large current on the shaft island mode.

6. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step two, the short circuit current calculation and selective protection analysis includes: the short circuit current calculation when a single shaft generator and a generator are parallel operated under navigation working condition; the withstand capacity of the original distribution board switch and the new switch is checked, and the requirements of the classification society are met.

7. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step three, the shaft generator is an upper and lower half type permanent magnet or electrically excited synchronous generator mounted without shaft extraction, and the rated output power is determined according to the system efficiency 0.92-0.93, and the no-load back electromotive force of the highest rotating speed is not greater than 820V.

8. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step three, the frequency converter is AFE active front end frequency converter or DFE diode front end frequency converter, and the water-cooled type is adopted; the machine side module considers 1.1 times overload margin, and the network side module has 2 times rated current 2s short circuit current support capacity.

9. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step four, the onshore system joint debugging test includes: the equipment is shipped to the onshore test site for installation and debugging; single machine performance test: 25%-50%-75%-100% load test, steady voltage fluctuation rate ±6%-10%, frequency fluctuation rate ±5%; sudden load and sudden unloading test: 0-33%-66%-100% and 100%-0 load test, transient voltage fluctuation rate ±20%, recovery time 1.5s, frequency fluctuation rate ±10%, recovery time 5s; and car function test: manual and automatic combination distribution board for parallel operation, load transfer test, to ensure power sharing and grid stability.

10. The method of designing a retrofitting shaft generator system for an operating marine vessel of claim 1, wherein, In step five, the real ship installation includes: the equipment is hoisted to the installation position, the base of the shaft motor and the frequency converter is welded with the ship body; the half expansion sleeve flange is fixed on the original ship shaft, the lower half motor rotor is connected with the expansion sleeve flange and rotated to the lower side, the other half rotor is installed, the foot bolts are adjusted to make the axial clearance of the motor front and rear end consistent, the stator and rotor are aligned; the jack is installed according to the calculation book, to ensure that the jacking force is perpendicular to the shaft center line, the measured bearing load and the theoretical value deviation is within ±20%; the real ship debugging includes insulation detection: insulation resistance is not less than 1MΩ, monitoring alarm function test and shaft switch cabinet interlocking and protection function test; trial report includes: shaft generator island operation test: the main engine runs at 68-84rpm speed range, respectively runs at 100% load for 1 hour, records the voltage, current, frequency, power factor parameters; diesel and shaft generator manual parallel operation and splitting test, to ensure smooth load transfer; shaft generator fault automatic starting test and large load starting and stopping test, to verify the system stability.

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