An online evaluation method for cooling performance of wind turbine nacelle

Abstract

The present invention belongs to the field of wind power generation technology and relates to an online evaluation method for the cooling performance of a wind turbine nacelle. The method comprises the following steps: obtaining coolant hot-end temperature data and coolant cold-end temperature data during actual operation of the wind turbine nacelle; performing a difference calculation on the coolant hot-end temperature data and the coolant cold-end temperature data to obtain a coolant temperature difference; inputting the coolant hot-end temperature data, the coolant cold-end temperature data, and the coolant temperature difference into a constructed evaluation model to provide an early warning of the wind turbine nacelle's cooling performance; the evaluation model stores the coolant hot-end temperature alarm threshold, the coolant cold-end temperature alarm threshold, and the coolant temperature difference alarm threshold under typical operating conditions. The method quantifies the heat dissipation performance of the wind turbine nacelle, using the three indicators as a reference, and comprehensively considering the magnitude of the indicators to classify and discuss faults. The method provides guidance for wind turbine operation and maintenance personnel to conduct targeted on-site inspections, thereby reducing corresponding operation and maintenance costs. The method is relatively low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation, and in particular relates to an online evaluation method for the cooling performance of a wind turbine nacelle. Background Art

[0002] As wind turbines develop towards larger capacity and higher parameters, the rated power of electrical components such as inverters and generators inside the nacelle is also increasing. During operation, electrical components will generate a lot of heat. If the heat generated by the electrical components is greater than their heat dissipation, the cabin temperature will gradually rise, causing the electrical components to over-temperature alarm. Long-term high temperatures can easily cause electrical components in the cabin to malfunction and shut down, resulting in power generation loss and significantly affecting the service life of the electrical components. It is necessary to monitor such temperatures and strictly control them within a reasonable range.

[0003] Wind turbine nacelles are primarily cooled by air or liquid. Liquid cooling is typically used to improve the nacelle's heat transfer capacity, using liquid as the heat exchange medium. The liquid, pressurized by a water pump, flows through the nacelle's air-to-coolant heat exchanger, absorbing heat from the air before flowing through the air-to-coolant heat exchanger outside the nacelle to dissipate the heat. The heat dissipation performance of the nacelle determines the lifespan of the equipment. Wind turbines operate in relatively harsh environments, and during high-temperature periods, the heat dissipation of electrical components within the nacelle, such as the inverter and generator, requires particular monitoring. However, current methods rely on manual evaluation to determine if overheating is occurring, lacking online, real-time assessment and early warning capabilities. Summary of the Invention

[0004] The purpose of the present invention is to provide an online evaluation method for the cooling performance of a wind turbine nacelle, so as to solve the technical problem that the prior art relies on manual judgment of whether the temperature is overheated and lacks online real-time evaluation and early warning means.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for online evaluation of cooling performance of a wind turbine nacelle comprises the following steps:

[0007] S1. Obtaining the coolant hot-end temperature data and the coolant cold-end temperature data during the actual operation of the wind turbine nacelle;

[0008] S2. Calculate the difference between the coolant hot-end temperature data and the coolant cold-end temperature data to obtain the coolant temperature difference;

[0009] S3. Inputting the coolant hot-end temperature data, the coolant cold-end temperature data, and the coolant temperature difference into the constructed evaluation model to provide an early warning of the wind turbine nacelle cooling performance;

[0010] The evaluation model stores the coolant hot-end temperature alarm threshold, coolant cold-end temperature alarm threshold, and coolant temperature difference alarm threshold under typical working conditions.

[0011] Furthermore, when the difference between the coolant hot end temperature data and the coolant hot end temperature alarm threshold is greater than zero, a warning message is issued;

[0012] Or, when the difference between the coolant cold end temperature data and the coolant cold end temperature alarm threshold is greater than zero, a warning message is issued;

[0013] Or, when the difference between the coolant temperature difference and the coolant temperature difference alarm threshold is greater than zero, a warning message is issued;

[0014] Or, when the coolant temperature difference is less than zero, a warning message is issued.

[0015] Furthermore, in S3, the construction process of the evaluation model includes the following steps:

[0016] S3.1. Establish a wind turbine nacelle cooling system simulation device;

[0017] S3.2. Using the fan power generation and ambient temperature as boundary conditions, filter the fan coolant hot-end temperature data and coolant cold-end temperature data under each typical operating condition;

[0018] S3.3. Calculate the average temperature of the coolant hot end and the average temperature of the coolant cold end under each typical operating condition;

[0019] Calculate the average coolant temperature difference under each typical working condition based on the average coolant hot end temperature and the average coolant cold end temperature;

[0020] S3.4. Calculate the standard deviation of the coolant hot-end temperature under each typical operating condition based on the average coolant hot-end temperature obtained in S3.3 and the coolant hot-end temperature data obtained in S3.2.

[0021] Calculate the standard deviation of the coolant cold end temperature under each typical operating condition based on the average coolant cold end temperature obtained in S3.3 and the coolant cold end temperature data obtained in S3.2;

[0022] Calculate the standard deviation of the coolant temperature difference under each working condition based on the average coolant hot end temperature, the average coolant cold end temperature, and the coolant average temperature difference;

[0023] S3.5. Calculate the coolant hot-end temperature alarm threshold based on the average coolant hot-end temperature obtained in S3.3 and the coolant hot-end temperature standard deviation obtained in S3.4;

[0024] The coolant cold end temperature alarm threshold is calculated based on the coolant cold end temperature average value obtained in S3.3 and the coolant cold end temperature standard deviation value obtained in S3.4;

[0025] The coolant temperature difference alarm threshold is calculated based on the coolant average temperature difference value obtained in S3.3 and the standard deviation value of the coolant temperature difference obtained in S3.4.

[0026] Furthermore, in S3.1, the wind turbine nacelle cooling system simulation device includes the nacelle inverter cabinet cooling system and the generator cooling system, specifically:

[0027] The two branches of the engine room inverter cabinet cooling system and the generator cooling system are connected in parallel to the coolant main line. A first temperature sensor is installed at the coolant pump outlet to measure the coolant cold end temperature;

[0028] After the coolant flows through the branches of the inverter cabinet and the generator branch and fully absorbs heat, it is collected at the coolant trunk line. A second temperature sensor is installed here to measure the temperature of the coolant hot end.

[0029] Furthermore, the nacelle inverter cabinet cooling system specifically comprises: installing n heat exchange plates in the inverter cabinet inside the nacelle, where n is greater than or equal to 3; connecting valve switches at the coolant inlet and outlet of each heat exchange plate to control the coolant flow rate; and connecting the n heat exchange plates in parallel to a solenoid valve master switch to control the coolant flow rate in the branch circuit;

[0030] The slip ring and the generator are connected in series to form the generator cooling system. The generator cooling system is connected to the coolant branch. A balancing valve is installed at the coolant inlet of the generator cooling system to adjust the pressure of the coolant in the branch. The coolant outlet of the generator system is connected to a valve switch to control the on and off of the generator cooling branch.

[0031] Further, S3.2 is specifically:

[0032] Within the preset range of the wind turbine's rated power, a total of x typical power values ​​are selected, and the power generation data within the range of ±0.5% around the typical power value is classified into the typical power range;

[0033] Within the preset range of ambient temperature, a total of y typical ambient temperature values ​​are selected, and the ambient temperature data within the range of ±0.5°C around the typical ambient temperature value is included in the typical temperature value range;

[0034] After screening, outlier data are removed, and the fan coolant hot-end temperature data and coolant cold-end temperature data under x*y typical working conditions are obtained.

[0035] Furthermore, the calculation formulas for S3.3, the average temperature of the coolant hot end, the average temperature of the coolant cold end, and the average temperature difference of the coolant under each typical operating condition are as follows:

[0036]

[0037] Where H i is the average temperature of the coolant hot end under the i-th working condition, C i is the average temperature of the coolant cold end under the i-th working condition, θ i is the average temperature difference of the coolant under the i-th working condition, is the coolant hot end temperature value under the i-th working condition, is the coolant cold end temperature value under the i-th working condition, m i is the number of data items filtered under the i-th working condition.

[0038] Furthermore, in S3.4, the calculation formulas for the standard deviation of the coolant hot-end temperature, the standard deviation of the coolant cold-end temperature, and the standard deviation of the coolant temperature difference under each typical operating condition are as follows:

[0039]

[0040] in, is the standard deviation of the coolant hot end temperature under the i-th working condition, is the standard deviation of the coolant hot end temperature under the i-th working condition, is the standard deviation of the coolant temperature difference under the i-th working condition.

[0041] Furthermore, the calculation formulas for the coolant hot end temperature alarm threshold, the coolant cold end temperature alarm threshold, and the coolant temperature difference alarm threshold in S3.5 are:

[0042]

[0043]

[0044]

[0045] In the formula, the value of k is an integer greater than or equal to 3. is the coolant hot end temperature alarm threshold under the i-th working condition, The coolant cold end temperature alarm threshold under the i-th working condition, is the coolant temperature difference alarm threshold under the i-th working condition.

[0046] Furthermore, in S1, the cabin average temperature value is also obtained;

[0047] The evaluation model calculates the temperature efficiency based on the average cabin temperature, the coolant hot-end temperature data, and the coolant cold-end temperature data. The calculation method stored in the evaluation model is shown in the following formula:

[0048]

[0049] Where, Et is the temperature efficiency value; T0 is the average temperature value in the cabin; T1 is the coolant cold end temperature data; T2 is the coolant hot end temperature data.

[0050] Compared with the prior art, the present invention has the following beneficial technical effects:

[0051] The present invention discloses an online evaluation method for the cooling performance of a wind turbine cabin, proposes an online evaluation method for the cooling performance of a wind turbine cabin, can monitor and evaluate the cooling performance health of the cabin in real time, comprehensively compares the coolant temperature and its temperature difference temperature, can evaluate the cooling condition of the cabin, provides guidance for wind power operation and maintenance personnel to conduct targeted maintenance on site, and reduces the corresponding operation and maintenance costs; the cost is low, and the health of the cabin cooling performance can be evaluated online, effectively reducing the failure shutdown and power generation loss caused by cabin overheating; the evaluation model stores the coolant hot end temperature alarm threshold, the coolant cold end temperature alarm threshold and the coolant temperature difference alarm threshold under typical working conditions, quantifies the heat dissipation performance of the wind turbine cabin, and refers to the three indicators at the same time, and comprehensively considers the size of the indicators to carry out classification discussion of faults.

[0052] Furthermore, the wind turbine cabin cooling system simulation device includes a cabin inverter cabinet cooling system and a generator cooling system. The systems within the wind turbine cabin that generate a lot of heat mainly include: the generator system, the inverter cabinet system, and the gearbox system. The generator system and the inverter cabinet system have high temperatures and require coolant cooling. When designing the cooling system, wind turbine manufacturers usually integrate the two components to save costs. The gearbox system is cooled with lubricating oil. For direct-drive wind turbines without a gearbox system, gearbox cooling is not considered. The simulation of the present invention also takes practical issues into consideration. Therefore, both the cabin inverter cabinet cooling system and the generator cooling system are added to the simulation device, resulting in more realistic simulated cooling data.

[0053] Furthermore, the present invention uses fan power generation and ambient temperature as boundary conditions to screen fan coolant hot-end and coolant cold-end temperature data under various typical operating conditions. This is because natural wind speeds fluctuate in real time, leading to variable fan operating conditions. The fan cooling system generates varying amounts of heat under different operating conditions, and the corresponding warning thresholds should also change dynamically due to the varying coolant temperature and temperature difference values. Therefore, the proposed method divides the fan operating conditions into intervals, allowing for targeted assessment and early warning of the fan's cooling status under different operating conditions.

[0054] Furthermore, the present invention introduces a temperature efficiency evaluation metric to assess cabin cooling performance. Temperature efficiency is a key indicator for evaluating cabin heat dissipation performance. The calculation results can be used to determine cabin coolant degradation and identify sensors with abnormal coolant temperatures, facilitating precise guidance for operators on targeted replenishment and replacement of cabin coolant, as well as replacement and repair of temperature sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Schematic diagram of a flow chart of an online evaluation method for cooling performance of a wind turbine nacelle according to the present invention;

[0056] Figure 2 A schematic diagram of the construction process of the evaluation model of the present invention;

[0057] Figure 3 It is the overall flow chart of the present invention;

[0058] Figure 4 This is a schematic diagram of the installation of a wind turbine cabin coolant temperature sensor according to the present invention;

[0059] Figure 5 This is a structural block diagram of a terminal device provided in an embodiment of the present invention.

[0060] The meanings of the reference numerals are as follows:

[0061] 1. Heat exchange plate; 2. First temperature sensor; 3. Second temperature sensor; 4. Solenoid valve; 5. Generator; 6. Slip ring; 7. Balancing valve; 8. Valve switch; 9. Pressure gauge; 10. Pressure storage tank; 11. Safety valve; 12. Heat exchanger; 13. Three-phase valve; 14. Coolant pump;

[0062] 101. Processor; 102. Input device; 103. Output device; 104. Memory; 105. Bus. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following is a further detailed description with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0064] The components described and illustrated in the drawings and embodiments of the present invention may be arranged and designed in a variety of different configurations. Therefore, the detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. All other embodiments derived by those skilled in the art based on the drawings and embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0065] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that a process, element, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to the process, element, method, article or apparatus.

[0066] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0067] like Figure 1 and Figure 3 As shown, the present invention discloses an online evaluation method for the cooling performance of a wind turbine nacelle, comprising the following steps:

[0068] S1. Obtaining the coolant hot-end temperature data and the coolant cold-end temperature data during the actual operation of the wind turbine nacelle;

[0069] S2. Calculate the difference between the coolant hot-end temperature data and the coolant cold-end temperature data to obtain the coolant temperature difference;

[0070] S3. Inputting the coolant hot-end temperature data, the coolant cold-end temperature data, and the coolant temperature difference into the constructed evaluation model to provide an early warning of the wind turbine nacelle cooling performance;

[0071] The evaluation model stores the coolant hot-end temperature alarm threshold, coolant cold-end temperature alarm threshold, and coolant temperature difference alarm threshold under typical working conditions.

[0072] like Figure 2 As shown in Figure 2, the establishment of the evaluation model specifically includes the following steps:

[0073] S3.1、Establish Figure 4 The wind turbine nacelle cooling system simulation device shown:

[0074] The wind turbine nacelle cooling system simulation device includes the nacelle inverter cabinet cooling system and the generator cooling system;

[0075] Engine room inverter cabinet cooling system: n (n ≥ 3) heat exchange plates 1 of the same model are installed in the inverter cabinet inside the engine room. The coolant inlet and outlet of each heat exchange plate 1 are each connected to a valve switch 8 of the same model to control the flow rate of the coolant. The n heat exchange plates 1 are connected in parallel.

[0076] Each of the n heat exchange plates 1 is connected in parallel to a solenoid valve 4 master switch to control the flow rate of the coolant in the branch. A vent is left at the converging branch of each parallel branch to facilitate the discharge of gas mixed with the coolant during the heat exchange process of each heat exchange plate 1, and at the same time has the function of balancing the pressure of each branch pipeline.

[0077] The slip ring 6 is connected in series with the generator 5 to form a generator cooling system connected to the coolant branch. A balancing valve 7 is installed at the coolant inlet and outlet of the generator cooling system to adjust the pressure of the coolant in the branch. A valve switch 8 is connected to the coolant outlet of the generator cooling system to control the on and off of the cooling branch of the generator 5.

[0078] The two branches of the cabin inverter cabinet cooling system and the generator cooling system are connected in parallel to the coolant main line. A first temperature sensor 2 is installed at the outlet of the coolant pump 14 to measure the coolant cold end temperature T1. The coolant flows through the branches of the inverter cabinet and the generator 5 branches and fully absorbs heat before being collected at the coolant main line. A second temperature sensor 3 is installed here to measure the coolant hot end temperature T2.

[0079] The coolant main line is equipped with a pressure gauge 9, a pressure storage tank 10, a safety valve 11, a heat exchanger 12, a balancing valve 7, a three-phase valve 13, and a coolant pump 14 in sequence from the coolant hot end temperature of the second temperature sensor 3 to the coolant cold end temperature of the first temperature sensor 2. The heat exchanger 12 is connected in parallel to the coolant main line, the inlet of the heat exchanger 12 is connected between the outlet of the safety valve 11 and the inlet of the balancing valve 7, and the outlet of the heat exchanger 12 is connected to the three-phase valve 13. The heat of the coolant is fully exchanged with the air at the atmospheric ambient temperature in the heat exchanger 12, and a vent is left.

[0080] The pressure gauge 9 is used to display the pressure of the coolant in the pipeline; the pressure storage tank 10 is used to store excess coolant; the safety valve 11 is used to keep the pipeline pressure below the set value and release the pressure if it exceeds the limit; the heat exchanger 12 is used for the coolant to dissipate heat by convection with the air after absorbing heat; the balancing valve 7 is used to adjust the pressure balance in the pipeline; the three-phase valve 13 ensures that the fluid can flow in and out of the three apertures; the coolant pump 14 is used to pressurize the liquid in the pipeline.

[0081] S3.2. Using the fan power generation and ambient temperature as boundary conditions, filter the fan coolant hot-end temperature data and coolant cold-end temperature data under each typical operating condition;

[0082] For a wind turbine, the steady-state data under various operating conditions are screened using the turbine's power generation and ambient temperature as boundary conditions. The specific principles for screening steady-state operating condition data are as follows:

[0083] Within the range of 60% to 100% of the rated power of the fan generator, 41 typical power values ​​were selected at intervals of 1%. The power generation data within the range of ±0.5% of the typical power value was included in the typical power range. Within the ambient temperature range of 5°C to 45°C, 41 typical ambient temperature values ​​were selected at intervals of 1°C. The ambient temperature data within the range of ±0.5°C of the typical ambient temperature value was included in the typical temperature value range. After screening, outlier data were removed, resulting in 1,681 fan coolant hot-end temperature and coolant cold-end temperature data under typical operating conditions.

[0084] S3.3. Calculate the average temperature of the coolant hot end and the average temperature of the coolant cold end under each typical operating condition;

[0085] Calculate the average coolant temperature difference under each typical working condition based on the average coolant hot end temperature and the average coolant cold end temperature;

[0086] The calculation formula is as follows:

[0087]

[0088] Where H i is the average temperature of the coolant hot end under the i-th working condition, C i is the average temperature of the coolant cold end under the i-th working condition, θ i is the average temperature difference of the coolant under the i-th working condition, is the coolant hot end temperature value under the i-th working condition, is the coolant cold end temperature value under the i-th working condition, m i is the number of data items filtered under the i-th working condition.

[0089] S3.4. Calculate the standard deviation of the coolant hot-end temperature under each typical operating condition based on the average coolant hot-end temperature obtained in S3.3 and the coolant hot-end temperature data obtained in S3.2.

[0090] Calculate the standard deviation of the coolant cold end temperature under each typical operating condition based on the average coolant cold end temperature obtained in S3.3 and the coolant cold end temperature data obtained in S3.2;

[0091] Calculate the standard deviation of the coolant temperature difference under each working condition based on the average coolant hot end temperature, the average coolant cold end temperature, and the coolant average temperature difference;

[0092] The calculation formula is as follows:

[0093]

[0094] is the standard deviation of the coolant hot end temperature under the i-th working condition, is the standard deviation of the coolant hot end temperature under the i-th working condition, is the standard deviation of the coolant temperature difference under the i-th working condition.

[0095] S3.5. Set three alarm thresholds for coolant hot-end temperature, coolant cold-end temperature, and coolant temperature difference based on normal distribution. The specific calculation basis is as follows:

[0096]

[0097]

[0098]

[0099] In the formula, the value of k is an integer greater than or equal to 3. is the coolant hot end temperature alarm threshold under the i-th working condition, is the coolant cold end temperature alarm threshold under the i-th working condition, is the coolant temperature difference alarm threshold under the i-th working condition.

[0100] like Figure 3 As shown in the figure, the evaluation model subtracts the coolant hot end temperature, coolant cold end temperature, and coolant temperature difference during actual operation from the alarm threshold under typical working conditions, and performs online evaluation based on the difference. The specific evaluation rules are as follows:

[0101] When the difference between the coolant hot-end temperature and the coolant cold-end temperature and the corresponding alarm threshold is much greater than zero, an early warning message is issued, suggesting that the operator focus on checking whether the sensor is damaged;

[0102] When the difference between the coolant temperature difference and the coolant temperature difference alarm threshold is greater than zero, a warning message is issued;

[0103] When the coolant temperature difference is less than zero, an early warning message is issued, and the operating personnel are advised to focus on checking whether the temperature sensor is installed upside down.

[0104] More preferably, in S1, the cabin average temperature value is also obtained, and the evaluation model calculates the temperature efficiency based on the cabin average temperature value, the coolant hot end temperature data, and the coolant cold end temperature data; the calculation method stored in the evaluation model is shown in the following formula:

[0105]

[0106] Where, E tis the temperature efficiency value; T0 is the average temperature value in the cabin; T1 is the temperature value of the coolant cold end; T2 is the temperature value of the coolant hot end. The temperature efficiency of the heat dissipation system is generally between 1 and 2.

[0107] Cabin cooling performance is evaluated based on temperature efficiency, a key indicator of cabin heat dissipation performance. A higher temperature efficiency indicates greater heat removal from the cabin and better cabin cooling.

[0108] For temperature efficiency, when the coolant hot-end temperature and the coolant cold-end temperature are both within the alarm threshold range and the temperature efficiency value is less than 1.2, it is considered that the heat exchange effect in the cabin is poor. At the same time, observe the changes in the coolant temperature difference. If the temperature difference is around 5°C (a large amount of data is statistically analyzed for normal heat exchange temperature differences, and the letter Tn can be used instead for different models), it means that the coolant heat transfer coefficient has decreased. Focus on checking whether the coolant has deterioration caused by impurity particle contamination; if the temperature difference is much greater than 5°C, focus on checking whether the coolant has leakage, blockage, etc., which may cause a decrease in coolant flow; if the temperature difference is greater than zero but much less than 5°C, focus on checking whether heating components such as the inverter and generator are damaged.

[0109] like Figure 5 As shown, the present invention also provides a terminal device, including a memory 104, a processor 101, an input device 102, an output device 103, a bus 105, and a computer program stored in the memory 104 and executable on the processor 101. When the processor 101 executes the computer program, the steps of the above-mentioned method for online evaluation of the cooling performance of a wind turbine cabin are implemented.

[0110] The method for online evaluation of wind turbine nacelle cooling performance according to the present invention may be implemented entirely in hardware, entirely in software, or in a combination of software and hardware. Furthermore, the present invention may be implemented as a computer program product embodied on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for online evaluation of cooling performance of a wind turbine nacelle, characterized in that: The following steps are involved: S1. Obtaining the coolant hot-end temperature data and the coolant cold-end temperature data during the actual operation of the wind turbine nacelle; S2. Calculate the difference between the coolant hot-end temperature data and the coolant cold-end temperature data to obtain the coolant temperature difference; S3. Inputting the coolant hot-end temperature data, the coolant cold-end temperature data, and the coolant temperature difference into the constructed evaluation model to provide an early warning of the wind turbine nacelle cooling performance; The evaluation model stores the coolant hot-end temperature alarm threshold, coolant cold-end temperature alarm threshold, and coolant temperature difference alarm threshold under typical working conditions; In S1, the average cabin temperature value is also obtained; The evaluation model calculates the temperature efficiency based on the average cabin temperature, the coolant hot-end temperature data, and the coolant cold-end temperature data. The calculation method stored in the evaluation model is shown in the following formula: Where, E t is the temperature efficiency value; T0 is the average temperature value in the cabin; T1 is the coolant cold end temperature data; T2 is the coolant hot end temperature data; In S3, the evaluation model construction process includes the following steps: S3.

1. Establish a wind turbine nacelle cooling system simulation device; S3.

2. Using the fan power generation and ambient temperature as boundary conditions, filter the fan coolant hot-end temperature data and coolant cold-end temperature data under each typical operating condition; S3.

3. Calculate the average temperature of the coolant hot end and the average temperature of the coolant cold end under each typical operating condition; Calculate the average coolant temperature difference under each typical working condition based on the average coolant hot end temperature and the average coolant cold end temperature; S3.

4. Calculate the standard deviation of the coolant hot-end temperature under each typical operating condition based on the average coolant hot-end temperature obtained in S3.3 and the coolant hot-end temperature data obtained in S3.

2. Calculate the standard deviation of the coolant cold end temperature under each typical operating condition based on the average coolant cold end temperature obtained in S3.3 and the coolant cold end temperature data obtained in S3.2; Calculate the standard deviation of the coolant temperature difference under each working condition based on the average coolant hot end temperature, the average coolant cold end temperature, and the coolant average temperature difference; S3.

5. Calculate the coolant hot-end temperature alarm threshold based on the average coolant hot-end temperature obtained in S3.3 and the coolant hot-end temperature standard deviation obtained in S3.4; The coolant cold end temperature alarm threshold is calculated based on the coolant cold end temperature average value obtained in S3.3 and the coolant cold end temperature standard deviation value obtained in S3.4; The coolant temperature difference alarm threshold is calculated based on the coolant average temperature difference value obtained in S3.3 and the standard deviation value of the coolant temperature difference obtained in S3.

4.

2. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 1, characterized in that: When the difference between the coolant hot end temperature data and the coolant hot end temperature alarm threshold is greater than zero, an early warning message is issued; Or, when the difference between the coolant cold end temperature data and the coolant cold end temperature alarm threshold is greater than zero, a warning message is issued; Or, when the difference between the coolant temperature difference and the coolant temperature difference alarm threshold is greater than zero, a warning message is issued; Or, when the coolant temperature difference is less than zero, a warning message is issued.

3. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 1, characterized in that: In S3.1, the wind turbine nacelle cooling system simulation device includes the nacelle inverter cabinet cooling system and the generator cooling system, specifically: The two branches of the cabin inverter cabinet cooling system and the generator cooling system are connected in parallel to the coolant main line, and a first temperature sensor (2) is installed at the outlet of the coolant pump (14) for measuring the coolant cold end temperature; The coolant flows through each branch of the frequency converter cabinet and the generator (5) branch and fully absorbs heat before being collected at the coolant trunk line, where a second temperature sensor (3) is installed to measure the temperature of the coolant hot end.

4. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 3, characterized in that: The engine room frequency converter cabinet cooling system specifically comprises: installing n heat exchange plates (1) in the frequency converter cabinet inside the engine room, where n is greater than or equal to 3; connecting a valve switch (8) at the coolant inlet and outlet of each heat exchange plate (1) to control the flow rate of the coolant; and connecting the n heat exchange plates (1) in parallel; and connecting the n heat exchange plates (1) in parallel to a solenoid valve (4) master switch to control the flow rate of the coolant in the branch circuit; The slip ring (6) and the generator (5) are connected in series to form a generator cooling system. The generator cooling system is connected to the coolant branch. A balancing valve (7) is installed at the coolant inlet of the generator cooling system to adjust the pressure of the coolant in the branch. The coolant outlet of the generator cooling system is connected to a valve switch (8) to control the on-off of the cooling branch of the generator (5).

5. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 1, characterized in that: S3.2, specifically: Within the preset range of the wind turbine's rated power, a total of x typical power values ​​are selected, and the power generation data within the range of ±0.5% around the typical power value is included in the typical power range; Within the preset range of ambient temperature, a total of y typical ambient temperature values ​​are selected, and the ambient temperature data within the range of ±0.5°C around the typical ambient temperature value is included in the typical temperature value range; After screening, outlier data are removed, and the fan coolant hot-end temperature data and coolant cold-end temperature data under x*y typical working conditions are obtained.

6. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 1, characterized in that: S3.

3. The calculation formulas for the average coolant hot-end temperature, the average coolant cold-end temperature, and the average coolant temperature difference under each typical operating condition are: ； Where, H i For the i The average temperature of the coolant hot end under each working condition is C i For the i The average temperature of the coolant cold end under each working condition is For the i The average temperature difference of the coolant under each working condition is For the i The coolant hot end temperature value under each working condition is: For the i The coolant cold end temperature value under each working condition is: For the i The number of data items filtered under each working condition.

7. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 6, characterized in that: In S3.4, the calculation formulas for the standard deviation of the coolant hot-end temperature, the standard deviation of the coolant cold-end temperature, and the standard deviation of the coolant temperature difference under each typical operating condition are as follows: ； in, For the i The standard deviation of the coolant hot end temperature under each working condition is: For the i The standard deviation of the coolant hot end temperature under each working condition is: For the i The standard deviation of the coolant temperature difference under different working conditions.

8. The online evaluation method for cooling performance of a wind turbine nacelle according to claim 7, characterized in that: In S3.5, the calculation formulas for the coolant hot-end temperature alarm threshold, coolant cold-end temperature alarm threshold, and coolant temperature difference alarm threshold are: ； In the formula, the value of k is an integer greater than or equal to 3. For the i The coolant hot end temperature alarm threshold under each working condition, No. i The coolant cold end temperature alarm threshold under each working condition, For the i Coolant temperature difference alarm threshold under different working conditions.

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