A method and device for selecting embedded cables in the gearbox of a wind turbine generator set

Abstract

This invention belongs to the field of wind power generation technology, specifically relating to a method and device for selecting pre-embedded cables for wind turbine gearboxes. The method first calculates the corresponding effective operating current based on the wind turbine blade load and the cyclic operating characteristics of the pitch system. Then, based on cable laying methods, cable insulation materials, temperature correction, and cable grouping correction in standards, it determines the current carrying capacity of a single core cable for each cable cross-sectional area. Finally, it compares the single-core cable current carrying capacity value with the final operating current required by the pitch system to determine the final single-core cable cross-sectional area. This invention, based on the cyclic load characteristics of the wind turbine pitch system and considering the cable laying method and ambient temperature, optimizes the single-core cable cross-sectional area, selecting a more suitable pre-embedded cable specification for the gearbox while ensuring the safe and reliable operation of the wind turbine, effectively reducing the occurrence of wind turbine operation failures.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation technology, specifically relating to a method and device for selecting pre-embedded cables for wind turbine gearboxes. Background Technology

[0002] The drivetrain of a doubly-fed induction generator (DFIG) wind turbine consists of major components such as the gearbox and generator. The three pitch control systems within the rotor are powered via pre-embedded cables in the gearbox, passing through pitch slip rings from within the nacelle cabinet. The selection of the current-carrying capacity of the pre-embedded cables in the gearbox directly determines the safety and reliability of the wind turbine system. A reasonable and effective calculation method can ensure the safe and reliable operation of the wind turbine. Therefore, the specifications of the pre-embedded cables in the gearbox directly affect the stability and safety of the pitch control system.

[0003] Currently, competition among wind turbine manufacturers is fierce, and the cost of wind turbines is continuously decreasing, making cost reduction a top priority. With the development of wind turbines, the trend towards larger blades has become established, and the power required for pitch drive systems is constantly increasing. When selecting pre-embedded cables for wind turbine gearboxes, the power of the three pitch motors in the pitch system is generally summed, and the current value is determined by dividing the summed power by the power factor and voltage. Then, the cable specifications are determined based on this current value in conjunction with the "GB50217-2018 Power Engineering Cable Design Standard". This method of calculating the single-core cross-sectional area of ​​the cable can easily lead to two situations: First, the selected single-core cross-sectional area is too large, resulting in high cable costs. The intense competition in the wind turbine market is unfavorable; the second scenario is that the "GB50217-2018 Power Engineering Cable Design Standard" is only an average result based on experience and historical data. The actual environment in which cables are located is complex and variable. For example, for multi-core cables, the cores will interfere with each other. This interference will make the actual current carrying capacity rating lower than the current carrying capacity rating in the "GB50217-2018 Power Engineering Cable Design Standard". This will result in the single-core cross-sectional area of ​​the cable selected by directly using the "GB50217-2018 Power Engineering Cable Design Standard" being too small, resulting in lower safety. Summary of the Invention

[0004] The purpose of this invention is to provide a method and device for selecting pre-embedded cables for wind turbine gearboxes, in order to solve the problems of high cable cost caused by excessively large single-core cross-sectional areas of cables selected by existing methods, or low safety caused by excessively small single-core cross-sectional areas.

[0005] To address the aforementioned technical problems, this invention provides a method for selecting pre-embedded cables for wind turbine gearboxes, comprising the following steps:

[0006] 1) Based on the rated power of all pitch motors in the pitch system of the wind turbine generator set, calculate the theoretical operating current I of the pitch system. 理论 ;

[0007] 2) The theoretical operating current I of the pitch system 理论 With the set reduction factor k 折减 Multiplying these components yields the effective operating current I of the pitch system after reducing the theoretical operating current. 有效 The reduction factor k 折减 The coefficient is set to account for the fact that the various pitch motors in the pitch system are not simultaneously at their rated power, and 0 < k 折减 <1;

[0008] 3) Select the insulation material and laying method of the cable that are compatible with the pitch system, and determine the rated single-circuit current carrying capacity corresponding to various cross-sectional areas of the cable under this insulation material and laying method.

[0009] 4) Compare the rated current carrying capacity of a single circuit with the set correction coefficient k 校正 Multiply by the product to calculate the single-circuit current-carrying capacity correction value, thus obtaining the single-circuit current-carrying capacity correction value corresponding to various cross-sectional areas of the cable; k 校正 >0;

[0010] 5) Compare the effective operating current I of the pitch system 有效 And the current carrying capacity correction value for each single loop, select one that is greater than or equal to the effective operating current I of the pitch system. 有效 And with the effective operating current I of the pitch system 有效 The cross-sectional area corresponding to the closest single-circuit current carrying capacity correction value is used to select the gearbox pre-embedded wire specifications based on the determined cable cross-sectional area.

[0011] The beneficial effects are as follows: When calculating the operating current of the pitch system, this invention considers the periodic operation characteristics of the blade load of the wind turbine pitch system and sets a reduction factor based on this characteristic. This reduction factor is used to calculate the effective operating current of the pitch system. Then, the laying method and insulation material of the wind turbine pitch system cables are taken into account to determine the rated single-circuit current carrying capacity corresponding to various cable cross-sectional areas. The rated single-circuit current carrying capacity is then corrected to calculate the corrected single-circuit current carrying capacity value. Finally, the effective operating current of the pitch system is compared with each corrected single-circuit current carrying capacity value to select the most suitable cable cross-sectional area, thus completing the selection of the gearbox pre-embedded cable specifications. The entire method of this invention is simple in principle, and the determined current carrying capacity of the pitch system power supply cable can meet the normal operation of the wind turbine. Moreover, the selected single-core cable cross-sectional area is more suitable than the cable cross-sectional area determined by the method of calculating the cumulative power of the three pitch motors of the wind turbine, thereby solving the problems of high cable cost caused by an excessively large single-core cable cross-sectional area or low safety caused by an excessively small single-core cable cross-sectional area.

[0012] Furthermore, in step 1), when calculating the theoretical operating current of the pitch system, it is also necessary to consider the set power supply voltage adjustment coefficient. Therefore, the theoretical operating current of the pitch system is:

[0013]

[0014] In the formula, I 理论 The theoretical operating current of the pitch system is represented by P; the rated power of all pitch motors is represented by U; and the three-phase supply voltage is represented by U. k represents the power factor of the pitch motor. 电压 This represents the power supply voltage regulation coefficient, which is the coefficient representing the actual fluctuation of the power supply voltage at the wind turbine site.

[0015] Its beneficial effects are as follows: This invention takes into account the actual situation and uses the set power supply voltage adjustment coefficient to calculate the theoretical operating current of the pitch system, thereby improving the accuracy of the calculation of the theoretical operating current of the pitch system.

[0016] Furthermore, the correction coefficients set in step 4) include the temperature correction coefficient k. 温度 The temperature correction coefficient k 温度 A coefficient, k, is set to account for the influence of ambient temperature on the insulation material of the cable. 温度 >0.

[0017] Its beneficial effects are as follows: considering that different ambient temperatures will affect the cable current, a temperature correction coefficient is set, and the rated current carrying capacity of a single circuit is corrected by using the set temperature correction coefficient.

[0018] Furthermore, the correction factors set in step 4) include the cable grouping correction factor k.成组 The cable grouping correction factor k 成组 To account for the influence between the cores of a multi-core cable when the laying method is selected, a coefficient is set, where 0 < k. 成组 ≤1.

[0019] Its beneficial effects are as follows: considering that the cores in a multi-core cable will be affected by each other, such as the compression between the cables, a cable grouping correction factor is set, and the single-circuit current carrying capacity rating is corrected by using the cable grouping correction factor.

[0020] Furthermore, the set correction factors also include cable grouping correction factors k. 成组 The cable grouping correction factor k 成组 To account for the influence between the cores of a multi-core cable when the laying method is selected, a coefficient is set, where 0 < k. 成组 ≤1; and the correction factor is the temperature correction factor k. 温度 Cable grouping correction factor k 成组 The product of.

[0021] Its beneficial effects are as follows: a temperature correction coefficient is set to take into account the influence of different ambient temperatures on cable current, and a cable grouping correction coefficient is set to take into account the mutual influence between the cores in a multi-core cable. Both factors are taken into account to correct the rated current carrying capacity of a single circuit, ensuring the accuracy of the calculation.

[0022] Furthermore,

[0023] Furthermore, k 电压 =0.9.

[0024] Furthermore, when the insulation material is PVC copper and the ambient temperature is 50°C, k 温度 =0.71.

[0025] Furthermore, when the laying method involves multi-core cables within cable trays and the number of multi-core cable trays is 2, k 成组 =1.

[0026] To solve the above-mentioned technical problems, the present invention also provides a wind turbine generator gearbox pre-embedded cable selection device, including a processor, which is used to execute computer program instructions to implement the wind turbine generator gearbox pre-embedded cable selection method described above, and achieve the same beneficial effects as the method. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the wind turbine pitch system of the present invention;

[0028] Figure 2 This is a flowchart of the method for selecting pre-embedded cables for wind turbine generator gearboxes according to the present invention;

[0029] Figure 3 The diagram shows the laying method from the "GB50217-2018 Standard for Cable Design in Power Engineering" used in this invention.

[0030] Figure 4 This is a cable current carrying capacity table diagram for the corresponding laying method in the "GB50217-2018 Electric Power Engineering Cable Design Standard" used in this invention;

[0031] Figure 5 This is a table of environmental temperature correction coefficients from the "GB50217-2018 Standard for Design of Cables for Power Engineering" used in this invention;

[0032] Figure 6 This is a table of correction coefficients for multi-core cables in the "GB50217-2018 Standard for Design of Cables for Power Engineering" used in this invention;

[0033] Figure 7 This is a structural diagram of the wind turbine generator gearbox pre-embedded cable selection device of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of this invention.

[0035] Example of selection method for pre-embedded cables in wind turbine gearbox:

[0036] The structural schematic diagram of the wind turbine pitch system described in this embodiment is as follows: Figure 1 As shown, the pitch system of a wind turbine generator (also known as a wind turbine) mainly consists of three independent pitch drives, three independent pitch gearboxes, and three independent pitch motors. For this pitch system, as... Figure 2 As shown, the specific process of the gearbox pre-embedded cable selection method (i.e., the wind turbine generator gearbox pre-embedded cable selection method of the present invention) is as follows:

[0037] Step 1: Sum the rated power of the three independent pitch motors in the wind turbine generator pitch system to obtain the summed power P:

[0038] P = 3 * P r (1)

[0039] In the formula, P r This indicates the rated power of each individual pitch motor.

[0040] Step two: Based on the accumulated power calculated in step one, and combined with the three-phase supply voltage, pitch motor power factor, and supply voltage regulation coefficient, calculate the theoretical operating current I of the pitch system. 理论 :

[0041]

[0042] In the formula, U represents the three-phase power supply voltage; k represents the power factor of the pitch motor. 电压 This represents the power supply voltage regulation coefficient, which is the coefficient representing the actual fluctuation of the power supply voltage at the wind turbine site. Generally, a fluctuation of ±10% is considered normal. In this embodiment, k... 电压 =0.9.

[0043] Step 3: Based on the periodic operation characteristics of the pitch system, i.e., the position of the three blades of the wind turbine is different at any given time, and the force load on the three blades is also different, therefore the output power of the three pitch motors is not simultaneously at the rated power. Based on this characteristic, a reduction factor is set, and the product of the theoretical operating current of the pitch system and the reduction factor is taken as the effective operating current I of the pitch system. 有效 :

[0044] I 有效 =k 折减 *I 理论 (3)

[0045] In the formula, k 折减 This represents the reduction factor, 0 < k 折减 <1, In this embodiment

[0046] Step 4: Select the insulation material and laying method of the cable that are compatible with the pitch system. According to the "GB50217-2018 Power Engineering Cable Design Standard", refer to the table to determine the rated single-circuit current carrying capacity corresponding to various cross-sectional areas of the cable under this insulation material and laying method.

[0047] In this embodiment, the cable insulation material is PVC copper, and the cable is laid as a multi-core cable directly inside the pre-reserved conduit of the gearbox, referring to Table 52-B1 of the "GB50217-2018 Power Engineering Cable Design Standard" for "Other Laying Methods with the Same Current Carrying Capacity—Multi-core Cable in a Cable Tray". Figure 3 As shown. Further refer to... Figure 4 From this, the corresponding single-loop current carrying capacity ratings for various cross-sectional areas are selected, and the selected data are marked with boxes. It should be noted that the multiple cross-sectional areas and their corresponding single-loop current carrying capacity ratings selected here are based on the theoretical operating current I of the pitch system calculated in step two. 理论 The list has been roughly selected.

[0048] Step 5: Given the selected cable insulation material, refer to the table in "GB50217-2018 Standard for Design of Cables for Power Engineering" to determine the temperature correction factor; this temperature correction factor k... 温度 A coefficient, k, is set to account for the influence of ambient temperature on the insulation material of the cable. 温度 >0.

[0049] In this embodiment, when the ambient temperature of the gearbox's embedded cable is 50°C, according to... Figure 5 The table shows the temperature correction coefficient (marked with a dashed box) when the insulation material is PVC or copper. 温度 It is 0.71.

[0050] Step Six: Given the selected cable laying method, refer to the table in "GB50217-2018 Power Engineering Cable Design Standard" to determine the cable grouping correction factor; this cable grouping correction factor k 成组 To account for the influence between the cores of a multi-core cable when the laying method is selected, a coefficient is set, where 0 < k. 成组 ≤1.

[0051] In this embodiment, when the laying method is that the multi-core cable is in the cable tray and the number of multi-core cable trays is 2, according to Figure 6 From the table, the cable grouping correction factor, marked with a dashed box, is obtained, i.e., k. 成组 The value is 1.

[0052] Step 7: Based on the obtained temperature correction coefficient k 温度 Cable grouping correction factor k 成组 The rated current carrying capacity of each single loop obtained in step four is corrected, that is, the temperature correction factor k is first adjusted. 温度 Cable grouping correction factor k 成组 Multiply to obtain the correction coefficient k 校正=k 温度 *k 成组 Then, the rated current carrying capacity of each single circuit is compared with the correction factor k. 校正 Multiply these values ​​to obtain the single-circuit current-carrying capacity correction value corresponding to various cross-sectional areas of the cable.

[0053] Step 8: Convert the effective operating current I of the pitch system from Step 3. 有效 Compare the current-carrying capacity correction values ​​of each single loop obtained in step seven, and select those that are greater than or equal to the effective operating current I of the pitch system. 有效 And with the effective operating current I of the pitch system 有效 The cross-sectional area corresponding to the closest single-circuit current carrying capacity correction value is the cross-sectional area specification of the single-core copper cable for the gearbox pre-embedded cable. After correction, it means that the safety margin of the selected cable cross-sectional area is larger, that is, the cross-sectional area should be larger than that without correction, so that the selected cable has a higher safety margin.

[0054] For example, targeting Figure 4 The single-loop current carrying capacity correction values ​​calculated from the selected data are shown in Table 1. The effective operating current I of the pitch system is calculated accordingly. 有效 When the value is 50A, 50 falls between 40.47 and 53.96 in column 3 of Table 1. Therefore, the cross-sectional area corresponding to 53.96 should be selected, which is 16mm². 2 .

[0055] Table 1

[0056] Cross-sectional area Single-circuit current carrying capacity rating Single-loop current carrying capacity correction value 1.0 13.5 9.585 1.5 17.5 12.425 2.5 24 17.04 4 32 22.72 6 41 29.11 10 57 40.47 16 76 53.96 25 96 68.16 35 119 84.49 50 144 102.24

[0057] In steps four through seven of this embodiment, the "GB50217-2018 Standard for Cable Design in Power Engineering" was used. Of course, using the updated standard is more accurate when the standard is updated. The various data stored in this standard, including the rated single-circuit current carrying capacity corresponding to various cable cross-sectional areas, temperature correction coefficients, and cable grouping correction coefficients, are all optimal values ​​obtained using experience and historical data. Of course, these parameters in the table can also be adaptively modified according to actual conditions, and then the modified parameters can be used for selecting the pre-embedded cables for the gearbox.

[0058] In summary, the principle of this invention is simple. First, based on the wind turbine blade load and the cyclic operating characteristics of the pitch system, the corresponding operating current of the pitch system is optimized. Then, according to the cable laying method, cable material, temperature correction, and cable grouping correction in the "GB50217-2018 Power Engineering Cable Design Standard," the current carrying capacity of the corresponding single-core cable under each cable cross-sectional area is determined. Finally, the final single-core cable cross-sectional area is determined by comparing the single-core cable current carrying capacity value with the final operating current required by the pitch system. This calculation method, based on the cyclic load characteristics of the wind turbine pitch system and considering the cable laying method and ambient temperature, optimizes the single-core cable cross-sectional area. Under the premise of ensuring the safe and reliable operation of the wind turbine, it selects a more suitable gearbox pre-embedded cable specification type, effectively reducing wind turbine operation failures, lowering wind turbine component costs, and improving market competitiveness.

[0059] Example of a wind turbine gearbox pre-embedded cable selection device:

[0060] An embodiment of the wind turbine generator gearbox pre-embedded cable selection device of the present invention is as follows: Figure 7 As shown, it includes a memory, a processor, and an internal bus. The processor and memory communicate and interact with each other via the internal bus. The memory includes at least one software function module stored in the memory. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby implementing the wind turbine gearbox pre-embedded cable selection method described in the embodiment of the present invention.

[0061] The processor can be a microprocessor (MCU), a programmable logic device (FPGA), or other processing devices. The memory can be any type of memory that stores information using electrical energy, such as RAM and ROM; it can also be any type of memory that stores information using magnetic energy, such as hard disks, floppy disks, magnetic tapes, magnetic core memory, bubble memory, and USB flash drives; it can also be any type of memory that stores information using optical methods, such as CDs and DVDs; and of course, it can also be other types of memory, such as quantum memory and graphene memory.

[0062] Specific implementation methods have been given above, but the present invention is not limited to the described implementation methods. The basic idea of ​​the present invention lies in the above basic scheme. For those skilled in the art, designing various modified models, formulas, and parameters based on the teachings of the present invention does not require creative effort. Changes, modifications, substitutions, and variations made to the implementation methods without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for selecting embedded cables in the gearbox of a wind turbine generator set, characterized in that, Includes the following steps: 1) Based on the rated power of all pitch motors in the pitch system of the wind turbine generator set, calculate the theoretical operating current of the pitch system. ; 2) The theoretical operating current of the pitch system With the set reduction factor Multiplying these components yields the effective operating current of the pitch system after reducing the theoretical operating current. The reduction factor The coefficient is set to account for the fact that the various pitch motors in the pitch system are not simultaneously at their rated power. ; 3) Select the insulation material and laying method of the cable that are compatible with the pitch system, and determine the rated single-circuit current carrying capacity corresponding to various cross-sectional areas of the cable under this insulation material and laying method; 4) Compare the rated current carrying capacity of a single circuit with the set correction factor. Multiply by the product to calculate the single-circuit current carrying capacity correction value, thereby obtaining the single-circuit current carrying capacity correction value corresponding to various cross-sectional areas of the cable; ; 5) Compare the effective operating current of the pitch system And the current carrying capacity correction value for each single loop, select one that is greater than or equal to the effective operating current of the pitch system. And with the effective operating current of the pitch system The cross-sectional area corresponding to the closest single-circuit current carrying capacity correction value is used to select the gearbox pre-embedded wire specifications based on the determined cable cross-sectional area.

2. The method for selecting embedded cables in the gearbox of a wind turbine generator set according to claim 1, characterized in that, In step 1), when calculating the theoretical operating current of the pitch system, it is also necessary to consider the set power supply voltage adjustment coefficient. Therefore, the theoretical operating current of the pitch system is: ； In the formula, This represents the theoretical operating current of the pitch control system; This represents the rated power of all pitch motors; Indicates the three-phase power supply voltage; Indicates the power factor of the pitch motor; This represents the power supply voltage regulation coefficient, which is the coefficient representing the actual fluctuation of the power supply voltage at the wind turbine site.

3. The method for selecting embedded cables in the gearbox of a wind turbine generator set according to claim 1, characterized in that, The correction factors set in step 4) include the temperature correction factor. Cable grouping correction factor The temperature correction coefficient A coefficient is set to account for the influence of ambient temperature on the insulation material of the cable. The cable grouping correction coefficient To account for the influence between the cores of the cable when the selected laying method is used and the cable is a multi-core cable, a coefficient is set. Furthermore, the correction factor is a temperature correction factor. Cable grouping correction factor The product of.

4. The method for selecting embedded cables for wind turbine gearboxes according to any one of claims 1 to 3, characterized in that, 。 5. The method for selecting embedded cables in the gearbox of a wind turbine generator set according to claim 2, characterized in that, 。 6. The method for selecting embedded cables in the gearbox of a wind turbine generator set according to claim 3, characterized in that, When the insulation material is PVC copper and the ambient temperature is 50℃ .

7. The method for selecting embedded cables in the gearbox of a wind turbine generator set according to claim 3, characterized in that, When the multi-core cable is laid in a cable tray and the number of multi-core cable trays is 2, .

8. A device for selecting pre-embedded cables for wind turbine generator gearboxes, characterized in that, Includes a processor, which executes computer program instructions to implement the method for selecting pre-embedded cables for wind turbine gearboxes as described in any one of claims 1 to 7.

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