Emergency feathering safety device and method for wind turbine overspeed

Abstract

The present invention relates to the technical field of wind power generation, and in particular to an emergency feathering safety device and method for wind turbines overspeeding, wherein the safety device comprises a control unit and a safety chain system, wherein the control unit can receive a voltage signal and / or a communication signal from the safety chain system; the safety chain system comprises a slip ring, a speed detection relay, a hub relay, a pitch motor relay and a pitch motor, wherein the coils of the speed detection relay and the hub relay are connected in series with the slip ring; the normally closed contact of the hub relay is connected in series with the coil of the pitch motor relay, the normally open contact of the pitch motor relay is connected in series with the pitch motor, and the normally open contact of the pitch motor relay is connected in series with the pitch motor, and then connected in parallel with the normally closed contact of the hub relay and the coil of the pitch motor relay. The present invention detects the speed of the main shaft of the generator, and the speed sensor is placed in the cabin, so that the inspection and maintenance do not affect the operation of the wind blades, and the operation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to an emergency propeller feathering safety device and method for an overspeeding wind turbine generator. Background Art

[0002] In the control system of wind turbines, the safety chain system is an important means to ensure the safety of wind turbine operation. The safety chain of wind turbines plays a vital role in wind turbines. Logically, its priority is higher than the control level. The safety chain is used to ensure the safety protection device of the wind turbine when an accident occurs. When a major accident occurs, the safe action of the device is ensured to make the wind turbine shut down urgently. The safety chain can be divided into two levels: the first-level safety chain and the second-level safety chain. The first-level safety chain is mainly a safety protection device for the main control system. It is the core part of the entire wind turbine safety chain. It can quickly detect and take countermeasures to prevent the further expansion of the fault. The second-level safety chain is mainly a safety protection device for key components such as impellers. When a serious fault occurs in the wind turbine, it will trigger a series of safety protection components to make the wind turbine shut down urgently.

[0003] Some wind turbines now have safety chain technology composed of SSB pitch system: the wind turbine is monitored by the wind turbine master control at any time during operation to determine whether the wind turbine operation is abnormal; if the master control detects any abnormality in the states such as cable twist angle exceeding value, pitch communication interruption, vibration value exceeding limit, generator speed overspeed, emergency stop button pressed, PLC crash, etc., the safety chain will be triggered to make the wind turbine blades perform emergency stop and pitch-up action. The sequence of triggering the safety chain action is: the master control sends a command to the safety module, the normally open contact of the safety module relay is disconnected, the slip ring emergency stop changes from high level to low level, the pitch system relay is powered off, the battery-powered pitch motor is pitch-up, and the wind turbine stops.

[0004] Wind turbines use safety chains as the highest level of protection against runaways. When the safety chain is disconnected, the system will receive an EFC emergency pitch signal command. However, when the main control sends the safety chain disconnect EFC signal command, the variable pitch slip ring EFC, the communication signal channel and the corresponding brush channel are misaligned or the safety module relay contacts are stuck, and the EFC signal is clamped at a high potential by the power supply voltage. Even if the safety chain is disconnected, the EFC signal cannot disconnect the variable pitch system relay, resulting in the variable pitch system being unable to perform an emergency pitch retraction and shutdown in an emergency situation when the safety chain is disconnected.

[0005] Prior art CN208831143U discloses a protection device for monitoring the speed of a wind turbine rotor, including a wind turbine rotor, a variable pitch safety chain loop, an inclination sensor and a safety protection device; a inclination sensor is provided at the center axis hole of the hub body; the safety protection device includes a controller and a relay, and the normally closed contact of the relay is electrically connected to a node in the variable pitch safety chain loop, which solves the technical defects of the speed overspeed monitoring device in the safety chain loop that cannot play a protective role due to failures and other reasons and is costly in the prior art. However, the protection device uses an inclination sensor to monitor the speed of the wind turbine blades. The inclination sensor is installed around the impeller, and the impeller needs to be controlled to achieve maintenance, which is inconvenient to use.

[0006] Therefore, it is necessary to provide an emergency propeller-feathering safety device and method for wind turbines in overspeed, to ensure that the variable pitch system can also be shut down in an emergency when the safety chain is disconnected, and to facilitate maintenance. Summary of the invention

[0007] In order to solve the above technical problems existing in the prior art, the present invention provides an emergency propeller feathering safety device and method for a wind turbine when overspeeding, aiming to provide additional protection for the wind turbine in case of safety chain failure to ensure its safe operation.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] An emergency feathering safety device for a wind turbine generator when overspeeding comprises a control unit and a safety chain system, wherein the control unit is capable of receiving a voltage signal and / or a communication signal from the safety chain system; the safety chain system comprises a slip ring, a speed detection relay, a hub relay, a pitch motor relay and a pitch motor, wherein the slip ring is arranged in a nacelle, and the speed detection relay and the coil of the hub relay are both connected in series with the slip ring; the normally closed contact of the hub relay is connected in series with the coil of the pitch motor relay, and the normally open contact of the pitch motor relay is connected in series with the pitch motor, and the normally open contact of the pitch motor relay is connected in series with the pitch motor and then connected in parallel with the normally closed contact of the hub relay and the coil of the pitch motor relay.

[0010] Furthermore, the emergency feathering safety device for the wind turbine overspeeding also includes an audible and visual alarm, one end of which is connected in parallel between the speed detection relay and the slip ring, and the other end of which is connected to a low level.

[0011] Furthermore, the emergency propeller feathering safety device for overspeeding the wind turbine further comprises a central control room alarm, one end of which is connected between the speed detection relay and the slip ring.

[0012] Furthermore, the emergency propeller feathering safety device for wind turbine overspeed also includes a speed measuring instrument, which is used to detect the speed of the generator and send a signal to the control unit when the speed exceeds the overspeed shutdown value. The control unit issues an instruction to disconnect the normally open contact of the speed detection relay.

[0013] Furthermore, the speed measuring instrument includes a power supply, an induction magnet and a speed sensor, wherein the induction magnet is arranged on the surface of a high-speed shaft connected to the generator; the speed sensor is arranged corresponding to the induction magnet, and the power supply is used to power the speed sensor.

[0014] Furthermore, a slot is arranged on the surface of the high-speed shaft, an induction magnet is arranged in the slot, and a length direction of the induction magnet is parallel to the axis of the high-speed shaft.

[0015] Furthermore, the distance between the rotation speed sensor and the induction magnet is less than 2 cm.

[0016] The present invention also provides a method for emergency propeller feathering when a wind turbine is overspeeding, using the above-mentioned emergency propeller feathering safety device when a wind turbine is overspeeding, comprising:

[0017] S1. Install the emergency feathering safety device for the wind turbine overspeed: connect a speed detection relay in series on the electrical connection line between the EFC outlet of the slip ring and the hollow shaft of the main shaft, and install an induction magnet and a speed sensor;

[0018] S2, run with load and determine the overspeed shutdown value;

[0019] S3. The overspeed shutdown value is set by the control unit, and the automatic propeller feathering action is performed according to the set overspeed shutdown value.

[0020] Furthermore, the overspeed shutdown value is set to N, and the first speed threshold is set to ,and <N; in the process of monitoring the high-speed shaft speed, determine the speed n of the high-speed shaft and N, Relationship:

[0021] like , keep the state of the pitch motor unchanged, and regularly and continuously monitor the high-speed shaft speed;

[0022] like , the pitch motor starts to move the blades back to a position less than 91°;

[0023] like , the pitch motor will operate to retract the blades to the 91° position.

[0024] Furthermore, a second threshold is set ,and > N,

[0025] like , the pitch motor will operate to retract the blades to the 91° position;

[0026] like , while the pitch motor feathers the blades to return them, torque braking is applied to the generator to reduce the generator speed.

[0027] Furthermore, the pitch speed of the variable pitch motor is determined according to the value of n and the mass of a single wind blade. The mass of a single wind blade is set to M, the shortest distance between the center of gravity of the wind blade and the center of rotation of the wind blade is set to r, and the threshold is set to ,but:

[0028] , the pitch motor feathering speed is carried out according to the preset value, where a is a constant;

[0029] , the pitch motor feathering speed is b times the preset value, and the value range of b is .

[0030] Furthermore, in When the pitch motor feathering speed is carried out according to the preset value, the high-speed shaft speed n is collected in real time. When n exceeds the rated speed of the generator, the pitch motor feathering speed is carried out at b times the preset value.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention provides an emergency feathering safety device and method for wind turbines in overspeed, which adds a speed detection relay to the existing safety link, and at the same time, the coils of the speed detection relay and the hub relay are connected in series with the slip ring; the normally closed contact of the hub relay is connected in series with the coil of the variable pitch motor relay, and the normally open contact of the variable pitch motor relay is connected in series with the variable pitch motor. When the speed of the generator main shaft exceeds the overspeed shutdown value, the speed detection relay is disconnected, and then the hub relay is powered off, the hub relay is disconnected, the variable pitch motor relay is turned off, the variable pitch motor is powered, and the variable pitch motor is activated to retract the blades, achieving an emergency shutdown and avoiding runaway accidents. The present invention detects the speed of the generator main shaft, and the speed sensor is placed in the cabin, so that inspection and maintenance do not affect the operation of the blades, and the operation is convenient.

[0033] In addition, the entire safety device is placed in the cabin, and the wiring layout does not affect the operation of the fan blades. Therefore, the present invention can be applied to the equipment layout of various types of fans and meet the needs of various types of fan modifications.

[0034] The present invention also realizes propeller retraction adjustment at different speeds by judging the rotation speed of the main shaft of the generator set, thereby avoiding accidents. At the same time, it also takes into account accident prevention when the rotation speed reaches a certain limit, avoids further increase of the rotation speed and thus avoids risks in advance, thereby further improving the safety factor of the wind power generation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A connection principle diagram of the emergency propeller feathering safety device for a wind turbine generator in overspeed provided by the present invention.

[0036] Figure 2 A structural diagram of a wind turbine to which the emergency feathering safety device provided by the present invention is applied when a wind turbine overspeeds.

[0037] Figure 3 This is a schematic structural diagram of the emergency propeller feathering safety device for a wind turbine generator in overspeed provided by the present invention.

[0038] Description of reference numerals:

[0039] 1. Fan blades, 2. Cabin, 3. Blade cover, 4. Slip ring, 5. Speed ​​sensor, 6. High-speed shaft, 7. Generator, 8. Gearbox, 9. Cabin cabinet. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the protection scope of the present invention.

[0041] It should be noted that, unless otherwise specifically stated, the relative arrangements of components and steps, and numerical expressions set forth in these embodiments should not be construed as limiting the scope of the present invention.

[0042] The following description of the exemplary embodiments is merely illustrative and is not intended to limit the present invention and its application or use in any sense. Techniques, methods and devices known to ordinary technicians in the relevant field may not be discussed in detail here, but where applicable, these techniques, methods and devices should be considered as part of this specification.

[0043] The present invention provides an emergency propeller feathering safety device for a wind turbine generator in overspeed, comprising a control unit and a safety chain system, wherein the control unit is capable of receiving a voltage signal and / or a communication signal from the safety chain system; Figure 1As shown, the safety chain system includes a slip ring EFC, a speed detection relay ZSK, a hub relay-5K1, a pitch motor relay 6K1 and a pitch motor. The slip ring EFC is arranged in the cabin, and the speed detection relay ZSK and the coil of the hub relay-5K1 are both connected in series with the slip ring EFC; the normally closed contact of the hub relay-5K1 is connected in series with the coil of the pitch motor relay 6K1, and the normally open contact of the pitch motor relay 6K1 is connected in series with the pitch motor. After the normally open contact of the pitch motor relay 6K1 is connected in series with the pitch motor, it is connected in parallel with the normally closed contact of the hub relay-5K1 and the coil of the pitch motor relay 6K1.

[0044] The emergency feathering safety device for wind turbine overspeed also includes an audible and visual alarm, one end of which is connected in parallel between the speed detection relay ZSK and the slip ring EFC, and the other end of which is connected to a low level. It also includes a central control room alarm, one end of which is connected between the speed detection relay ZSK and the slip ring EFC, and the other end is connected to other circuits.

[0045] The emergency propeller feathering safety device for wind turbine overspeed also includes a speed measuring instrument, which is used to detect the speed of the generator and send a signal to the control unit when the speed exceeds the overspeed shutdown value. The control unit issues an instruction to disconnect the normally open contact of the speed detection relay.

[0046] like Figure 2 The figure shows the structure of a wind turbine in which an emergency feathering safety device is applied when a wind turbine generator is overspeeding. The tower is upright on the ground, a nacelle 2 is arranged on the top of the tower, a generator, a nacelle cabinet and other components are arranged inside the nacelle 2, a blade cover 3 is arranged at the front end of the nacelle 2, a hub and a control unit are arranged inside the blade cover 3, three wind blades 1 and a variable pitch motor corresponding to the wind blades 1 are arranged in the hub, and the control unit can control the start of the variable pitch motor through the emergency feathering safety device when the wind turbine generator is overspeeding according to the signal of the speed measuring instrument, thereby realizing the feathering operation.

[0047] like Figure 3 As shown, a generator 7 is arranged inside the nacelle 2, and the high-speed shaft 6 of the generator 7 is connected to a gearbox 8. The gearbox 8 is connected to the fan blades 1 in the blade cover 3 through the main shaft. The rotation of the fan blades 1 causes the main shaft to rotate, thereby realizing power generation. A slip ring 4 is arranged on one side of the high-speed shaft 6, and the speed detection relay ZSK is connected to the safety link of the hollow shaft in the center of the slip ring from the slip ring 4. The slip ring outlet is also connected to the control unit; a power supply is arranged in the nacelle cabinet 9 to supply power to the emergency propeller safety device when the wind turbine overspeeds. The speed measuring instrument includes a power supply, an induction magnet and a speed sensor 5. The induction magnet is arranged on the surface of the high-speed shaft 6 connected to the generator 7; the speed sensor 5 is arranged corresponding to the induction magnet, and the power supply is used to supply power to the speed sensor 5.

[0048] A slot is provided on the surface of the high-speed shaft 6, and an induction magnet is provided in the slot, and the length direction of the induction magnet is parallel to the axis of the high-speed shaft 6. The distance between the speed sensor 5 and the induction magnet is less than 2 cm.

[0049] When the high-speed shaft 6 rotates at normal speed, the safety chain circuit switch Figure 1 As shown, the system is in normal working condition. However, after the original safety system of the wind turbine main engine issued a command, the wind turbine failed to shut down. At this time, the emergency feathering safety device intervenes when the wind turbine overspeeds. When it detects that the speed of high-speed shaft 6 exceeds the set alarm upper limit, an emergency signal is triggered and the speed detection relay ZSK closing point will be disconnected. At this time, the emergency shutdown EFC circuit loses power. At the same time, the hub relay -5K1 is powered off, the pitch motor relay 6K1 contactor is closed, and the battery supplies power to the pitch motor, triggering the feathering action.

[0050] For setting the alarm upper limit, set different speed values ​​and disconnect the EFC signal at different speed values. Check that the speed detection relay ZSK can correctly trigger the alarm to ensure the accuracy of the alarm upper limit of the speed measuring instrument. For example, when the generator speed is set to 1200rpm, run it with load and observe the working condition of the unit and whether it is disconnected from the grid and shut down.

[0051] The final set value is slightly higher than the normal value, which has a dual protection effect. It can ensure that the generator can be shut down in time when overspeeding, and avoid the wrong shutdown caused by the set value being too low. By monitoring whether the EFC signal is activated or not, and the variable pitch system for different models, no matter when the speed detector detects that the speed reaches the set value, the EFC signal link will be automatically disconnected, thereby achieving the purpose of retracting the propeller to stop. This technology is not only applicable to various models, but also has a high degree of flexibility and reliability, which helps to improve work efficiency and safety.

[0052] The present invention also provides a method for emergency propeller feathering when a wind turbine is overspeeding, using the above-mentioned emergency propeller feathering safety device when a wind turbine is overspeeding, comprising:

[0053] S1. Install the emergency feathering safety device for the wind turbine overspeed: connect the speed detection relay ZSK in series on the electrical connection line between the EFC outlet of the slip ring 4 and the hollow shaft, and install the induction magnet and the speed sensor 5;

[0054] S2, run with load and determine the overspeed shutdown value (i.e. the alarm upper limit);

[0055] S3. The overspeed shutdown value is set by the control unit, and the automatic propeller feathering action is performed according to the set overspeed shutdown value.

[0056] Set the overspeed shutdown value to N and set the first speed threshold ,and <N; in the process of monitoring the high-speed shaft speed, determine the speed n of the high-speed shaft and N, Relationship:

[0057] like , keep the state of the pitch motor unchanged, and regularly and continuously monitor the high-speed shaft speed;

[0058] like , the pitch motor starts to move the blades back to a position less than 91°;

[0059] like , the pitch motor will operate to retract the blades to the 91° position.

[0060] The first threshold The value range of is set according to the overspeed shutdown value, and the preferred value is 0.8-0.9 times the overspeed shutdown value.

[0061] In addition, set the second threshold ,and > N,

[0062] like , the pitch motor will operate to retract the blades to the 91° position;

[0063] like , while the variable pitch motor feathers the blades to return to the pitch, torque braking is applied to the generator to reduce the generator speed. The value range of is preferably 1-1.1 times of the overspeed shutdown value, which does not include the case where it is equal to the overspeed shutdown value.

[0064] The pitch speed of the variable pitch motor is determined by the n value and the mass of a single wind blade. The mass of a single wind blade is set to M, the shortest distance between the center of gravity of the wind blade and the center of rotation of the wind blade is r, and the threshold is set ,but:

[0065] , the pitch motor feathering speed is set according to the preset value, The calculated value is the centrifugal force during the rotation of a single fan blade, where a is the ratio of the square of the fan blade angular velocity to the square of the fan blade rotation speed;

[0066] , the pitch motor feathering speed is b times the preset value, and the value range of b is .

[0067] For the threshold The selection can be set according to the overspeed shutdown value, that is, the centrifugal force calculated when the speed n is the overspeed shutdown value, which is 0.9-1.05 times of the centrifugal force.

[0068] exist When the pitch motor feathering speed is carried out according to the preset value, the high-speed shaft speed n is collected in real time. When n exceeds the rated speed of the generator, the pitch motor feathering speed is carried out at b times the preset value.

[0069] The above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, a person skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An emergency feathering safety device for a wind turbine generator when it is overspeeding, characterized in that: It comprises a control unit and a safety chain system, wherein the control unit is capable of receiving a voltage signal and / or a communication signal from the safety chain system; the safety chain system comprises a slip ring, a speed detection relay, a hub relay, a pitch motor relay and a pitch motor, wherein the slip ring is arranged in the cabin, and the coils of the speed detection relay and the hub relay are both connected in series with the slip ring; the normally closed contact of the hub relay is connected in series with the coil of the pitch motor relay, and the normally open contact of the pitch motor relay is connected in series with the pitch motor, and the normally open contact of the pitch motor relay is connected in series with the pitch motor and then connected in parallel with the normally closed contact of the hub relay and the coil of the pitch motor relay; The speed of the high-speed shaft is n, the mass of a single fan blade is M, the shortest distance between the center of gravity of the fan blade and the center of rotation of the fan blade is r, and the threshold is set ,but: , the feathering speed of the pitch motor is carried out according to the preset value, where a is the ratio of the square of the angular velocity of the wind blade to the square of the rotational speed of the wind blade; , the pitch speed of the variable pitch motor is b times the preset value, and the value range of b is : The emergency feathering safety device for wind turbine overspeed also includes a speed measuring instrument, which is used to detect the speed of the generator and send a signal to the control unit when the speed exceeds the overspeed shutdown value. The control unit issues an instruction to disconnect the normally open contact of the speed detection relay. The speed measuring instrument comprises an induction magnet and a speed sensor, wherein the induction magnet is arranged on the surface of a high-speed shaft connected to the generator; and the speed sensor is arranged corresponding to the induction magnet; Set the overspeed shutdown value to N and set the first speed threshold ,and <N; in the process of monitoring the high-speed shaft speed, determine the speed n of the high-speed shaft and N, Relationship: like , keep the state of the pitch motor unchanged, and regularly and continuously monitor the high-speed shaft speed; like , the pitch motor starts to move the blades back to a position less than 91°; First threshold The value range is 0.8-0.9 times the overspeed shutdown value; like , the pitch motor will operate to retract the blades to the 91° position; In addition, set the second threshold ,and > N, like , the pitch motor will operate to retract the blades to the 91° position; like , while the pitch motor feathers the blades to return to the pitch, torque braking is applied to the generator; for the second threshold The value range is 1-1.1 times the overspeed shutdown value.

2. The wind turbine overspeed emergency feathering safety device according to claim 1, characterized in that: The emergency propeller feathering safety device for overspeeding of the wind turbine also includes an audible and visual alarm, one end of which is connected in parallel between the speed detection relay and the slip ring, and the other end of which is connected to a low level.

3. The wind turbine overspeed emergency feathering safety device according to claim 1, characterized in that: The emergency propeller feathering safety device for overspeeding of the wind turbine generator further comprises a central control room alarm, one end of which is connected between the speed detection relay and the slip ring.

4. The wind turbine overspeed emergency feathering safety device according to claim 1, characterized in that: The rotation speed measuring instrument comprises a power supply, and the power supply is used for supplying power to the rotation speed sensor.

5. The wind turbine overspeed emergency feathering safety device according to claim 4, characterized in that: A slot is arranged on the surface of the high-speed shaft, an induction magnet is arranged in the slot, and a length direction of the induction magnet is parallel to the axis of the high-speed shaft; The distance between the rotation speed sensor and the induction magnet is less than 2 cm.

6. A method for emergency feathering of a wind turbine when overspeeding, using the emergency feathering safety device for wind turbine when overspeeding according to any one of claims 1 to 5, characterized in that: include: S1. Install the emergency feathering safety device for the wind turbine overspeed: connect a speed detection relay in series on the electrical connection line between the EFC outlet of the slip ring and the hollow shaft, and install an induction magnet and a speed sensor; S2, run with load and determine the overspeed shutdown value; S3. The overspeed shutdown value is set by the control unit, and the automatic propeller feathering action is performed according to the set overspeed shutdown value.

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