A Double-Fed Wind Turbine Overspeed Protection System and Method

Abstract

The present invention discloses a double-fed wind turbine overspeed protection system and method, including a PLC controller, an overspeed protector, a first speed sensor for detecting the low-speed shaft speed of the wind turbine, a second speed sensor for detecting the high-speed shaft speed of the wind turbine, and a power supply for providing electrical energy. The input end of the PLC controller is connected to the output ends of the first speed sensor and the second speed sensor. The input end of the overspeed protector is connected to the output ends of the first speed sensor and the second speed sensor. The output end of the PLC controller is connected to the control end of the wind turbine. The PLC controller is connected to the overspeed protector. This system and method can ensure that the wind turbine does not overspeed during operation and improve the safety of the wind turbine operation.

Description

Technical Field

[0001] The invention belongs to the field of wind power generation, and relates to an overspeed protection system and method for a doubly-fed wind turbine generator set. Background Art

[0002] In recent years, with the continuous growth of the installed capacity of wind turbine generators in China and the continuous increase of the operation time of old units, the situation of overspeed of wind turbine generators caused by different reasons is increasing, and the most serious is the occurrence of tower collapse accidents. In order to avoid large accidents caused by overspeed, when overspeed occurs, the wind turbine generator set can detect overspeed and take necessary measures to prevent the accident from expanding. Summary of the Invention

[0003] The purpose of the invention is to overcome the shortcomings of the above-mentioned prior art, and provide an overspeed protection system and method for a doubly-fed wind turbine generator set, which can ensure that the wind turbine generator set does not overspeed during operation and improve the operation safety of the wind turbine generator set.

[0004] To achieve the above purpose, the overspeed protection system for a doubly-fed wind turbine generator set of the invention includes a PLC controller, an overspeed protector, a first speed sensor for detecting the speed of the low-speed shaft of the wind turbine generator set, a second speed sensor for detecting the speed of the high-speed shaft of the wind turbine generator set, and a power supply for providing electric energy. The input end of the PLC controller is connected to the output ends of the first speed sensor and the second speed sensor. The input end of the overspeed protector is connected to the output ends of the first speed sensor and the second speed sensor. The output end of the PLC controller is connected to the control end of the wind turbine generator set. The PLC controller is connected to the overspeed protector.

[0005] The first speed sensor is an inductive sensor, and the first speed sensor is composed of two proximity switches installed on the low-speed shaft.

[0006] The second speed sensor is an encoder installed on the motor side.

[0007] The distance between the probe of the first speed sensor and the low-speed shaft is 6.4 mm.

[0008] The overspeed protection method for a doubly-fed wind turbine generator set of the invention includes the following steps:

[0009] The first speed sensor detects the rotational speed information of the low-speed shaft of the wind turbine in real time and sends the rotational speed information of the low-speed shaft of the wind turbine to the PLC controller and the overspeed protector. The PLC controller determines whether the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the low-speed shaft. When the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the low-speed shaft, it controls the wind turbine to perform a shutdown operation. The overspeed protector determines whether the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the low-speed shaft. When the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the low-speed shaft, it generates a first alarm command and sends the first alarm command to the PLC controller. The PLC controller triggers the safety chain according to the first alarm command and starts an emergency stop command to stop the rotation of the wind turbine.

[0010] The second speed sensor detects the rotational speed information of the high-speed shaft of the wind turbine in real time and sends the rotational speed information of the high-speed shaft of the wind turbine to the PLC controller and the overspeed protector. The PLC controller determines whether the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the high-speed shaft. When the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the high-speed shaft, it controls the wind turbine to perform a shutdown operation. The overspeed protector determines whether the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the high-speed shaft. When the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the high-speed shaft, it generates a second alarm command and sends the second alarm command to the PLC controller. The PLC controller triggers the safety chain according to the second alarm command and starts an emergency stop command to stop the rotation of the wind turbine.

[0011] The rotational speed alarm value of the low-speed shaft is greater than the preset maximum rotational speed value of the low-speed shaft; the rotational speed alarm value of the high-speed shaft is greater than the preset maximum rotational speed value of the high-speed shaft.

[0012] The present invention has the following beneficial effects:

[0013] When the overspeed protection system and method for a doubly-fed wind turbine unit of the present invention are specifically operated, a two-stage protection method is adopted to protect the wind turbine unit. Among them, the PLC controller determines whether the rotational speeds of the high-speed shaft and the low-speed shaft are normal. When they are abnormal, the PLC controller controls the wind turbine to stop rotating. When the PLC controller cannot normally control the wind turbine to stop rotating, the rotational speeds of the high-speed shaft and the low-speed shaft continue to increase. The overspeed protector determines whether the rotational speeds of the high-speed shaft and the low-speed shaft exceed the warning value. When the rotational speed of the high-speed shaft exceeds the warning value or when the rotational speed of the low-speed shaft exceeds the warning value, the wind turbine is forced to stop rotating through an emergency shutdown command to ensure that the wind turbine does not experience overspeed during operation, improve the operating safety of the wind turbine, and avoid the expansion of accidents.

[0014] Furthermore, the first rotational speed sensor consists of two proximity switches, which has a relatively low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the schematic diagram of the present invention.

[0016] Among them, 1 is the first rotational speed sensor, 2 is the second rotational speed sensor, 3 is the overspeed protector, and 4 is the PLC controller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings:

[0018] Reference Figure 1 , the overspeed protection system of the doubly-fed wind turbine generator set described in the present invention includes a PLC controller 4, an overspeed protector 3, a first rotational speed sensor 1 for detecting the rotational speed of the low-speed shaft of the wind turbine generator set, a second rotational speed sensor 2 for detecting the rotational speed of the high-speed shaft of the wind turbine generator set, and a power supply for providing electric energy. The input end of the PLC controller 4 is connected to the output ends of the first rotational speed sensor 1 and the second rotational speed sensor 2. The input end of the overspeed protector 3 is connected to the output ends of the first rotational speed sensor 1 and the second rotational speed sensor 2. The output end of the PLC controller 4 is connected to the control end of the wind turbine generator set. The PLC controller 4 is connected to the overspeed protector 3.

[0019] The first rotational speed sensor 1 is an inductive sensor, and the first rotational speed sensor 1 consists of two proximity switches installed on the low-speed shaft. The distance between the probe of the first rotational speed sensor 1 and the low-speed shaft is 6.4 mm. The second rotational speed sensor 2 is an encoder installed on the motor side.

[0020] The parameters of the proximity switches are shown in Table 1:

[0021] Table 1

[0022] Dimension M18 / L = 70 Inductive distance 8mm (f) Material Special steel Operating voltage 10~36V (DC) Frequency 200Hz Load current 100mA

[0023] The operating parameters of the overspeed protector 3 are shown in Table 2:

[0024] Table 2

[0025]

[0026]

[0027] The overspeed protection method of the doubly-fed wind turbine generator set described in the present invention includes the following steps:

[0028] The first speed sensor 1 detects the rotational speed information of the low-speed shaft of the wind turbine in real time and sends the rotational speed information of the low-speed shaft of the wind turbine to the PLC controller 4 and the overspeed protector 3. The PLC controller 4 determines whether the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the low-speed shaft. When the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the low-speed shaft, it controls the wind turbine to perform a shutdown operation; the overspeed protector 3 determines whether the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the low-speed shaft. When the rotational speed of the low-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the low-speed shaft, it generates a first alarm instruction and sends the first alarm instruction to the PLC controller 4. The PLC controller 4 triggers the safety chain according to the first alarm instruction and starts an emergency stop command, causing the wind turbine to stop rotating;

[0029] The second speed sensor 2 detects the rotational speed information of the high-speed shaft of the wind turbine in real time and sends the rotational speed information of the high-speed shaft of the wind turbine to the PLC controller 4 and the overspeed protector 3. The PLC controller 4 determines whether the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the high-speed shaft. When the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the preset maximum rotational speed of the high-speed shaft, it controls the wind turbine to perform a shutdown operation; the overspeed protector 3 determines whether the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the high-speed shaft. When the rotational speed of the high-speed shaft of the current wind turbine is greater than or equal to the rotational speed alarm value of the high-speed shaft, it generates a second alarm instruction and sends the second alarm instruction to the PLC controller 4. The PLC controller 4 triggers the safety chain according to the second alarm instruction and starts an emergency stop command, causing the wind turbine to stop rotating.

[0030] Wherein, the rotational speed alarm value of the low-speed shaft is greater than the preset maximum rotational speed value of the low-speed shaft; the rotational speed alarm value of the high-speed shaft is greater than the preset maximum rotational speed value of the high-speed shaft.

[0031] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Any simple modifications, equivalent changes or decorations made by those skilled in the art using the disclosed technical content all fall within the protection scope of the present invention.

Claims

1. A double-fed wind turbine overspeed protection method, characterized in that, Based on a double-fed wind turbine overspeed protection system, the double-fed wind turbine overspeed protection system includes a PLC controller (4), an overspeed protector (3), a first speed sensor (1) for detecting the low-speed shaft speed of the wind turbine, a second speed sensor (2) for detecting the high-speed shaft speed of the wind turbine, and a power supply for providing electrical energy. The input end of the PLC controller (4) is connected to the output ends of the first speed sensor (1) and the second speed sensor (2). The input end of the overspeed protector (3) is connected to the output ends of the first speed sensor (1) and the second speed sensor (2). The output end of the PLC controller (4) is connected to the control end of the wind turbine. The PLC controller (4) is connected to the overspeed protector (3). It includes the following steps: The first speed sensor (1) detects the speed information of the low-speed shaft of the wind turbine in real time and sends the speed information of the low-speed shaft of the wind turbine to the PLC controller (4) and the overspeed protector (3). The PLC controller (4) judges whether the current speed of the low-speed shaft of the wind turbine is greater than or equal to the preset maximum low-speed shaft speed. When the current speed of the low-speed shaft of the wind turbine is greater than or equal to the preset maximum low-speed shaft speed, it controls the wind turbine to perform a shutdown operation. The overspeed protector (3) judges whether the current speed of the low-speed shaft of the wind turbine is greater than or equal to the low-speed shaft speed alarm value. When the current speed of the low-speed shaft of the wind turbine is greater than or equal to the low-speed shaft speed alarm value, it generates a first alarm instruction and sends the first alarm instruction to the PLC controller (4). The PLC controller (4) triggers the safety chain according to the first alarm instruction and starts an emergency stop command to stop the rotation of the wind turbine. The second speed sensor (2) detects the speed information of the high-speed shaft of the wind turbine in real time and sends the speed information of the high-speed shaft of the wind turbine to the PLC controller (4) and the overspeed protector (3). The PLC controller (4) judges whether the current speed of the high-speed shaft of the wind turbine is greater than or equal to the preset maximum high-speed shaft speed. When the current speed of the high-speed shaft of the wind turbine is greater than or equal to the preset maximum high-speed shaft speed, it controls the wind turbine to perform a shutdown operation. The overspeed protector (3) judges whether the current speed of the high-speed shaft of the wind turbine is greater than or equal to the high-speed shaft speed alarm value. When the current speed of the high-speed shaft of the wind turbine is greater than or equal to the high-speed shaft speed alarm value, it generates a second alarm instruction and sends the second alarm instruction to the PLC controller (4). The PLC controller (4) triggers the safety chain according to the second alarm instruction and starts an emergency stop command to stop the rotation of the wind turbine.

2. The overspeed protection method for a doubly-fed wind turbine generator set according to claim 1, wherein, The low-speed shaft speed alarm value is greater than the preset maximum low-speed shaft speed value; the high-speed shaft speed alarm value is greater than the preset maximum high-speed shaft speed value.

3. The overspeed protection method for a doubly-fed wind turbine generator set according to claim 1, characterized in that, The first speed sensor (1) is an inductive sensor, and the first speed sensor (1) is composed of two proximity switches installed on the low-speed shaft.

4. The overspeed protection method for a doubly-fed wind turbine generator set according to claim 1, wherein The second speed sensor (2) is an encoder installed on the motor side.

5. The overspeed protection method for a doubly-fed wind turbine generator set according to claim 1, characterized in that The distance between the probe of the first speed sensor (1) and the low-speed shaft is 6.4 mm.

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