CN218771279U - Non-contact type shaft current active release device for generator of wind turbine generator - Google Patents

Abstract

The utility model discloses a non-contact shaft current active release device of a wind turbine generator, which comprises a power-on ring, a power-on needle and an adjustable voltage source; the power leading ring is arranged on a rotating shaft of the generator and is close to a bearing of the generator, the needle tip of the conductive needle is close to and points to the power leading ring, the needle foot end of the conductive needle is electrically connected with the input end of an adjustable voltage source through a wire, and the output end of the adjustable voltage source is grounded; the utility model discloses an arrange near the generator bearing external most advanced conductive needle and the epaxial electricity of generator commentaries on classics between the ring plus voltage for when axle voltage does not exceed bearing oil film breakdown voltage, just appear most advanced conductive needle and draw and be punctured between the ring, the axle current is from this release, the utility model discloses can not produce too big pressure drop, contactless nothing simultaneously wears and does not need to be changed, can not pollute fluid, has the universality, need not change generator bearing type model, and intensity, life-span and with higher costs all more have the advantage.

Description

Non-contact type shaft current active release device for generator of wind turbine generator

Technical Field

The utility model belongs to the technical field of the technique of wind turbine generator shaft current release and specifically relates to indicate a wind turbine generator non-contact axle current initiative release.

Background

During the rotation of the generator, unbalanced magnetic flux acts on the rotating shaft to generate induced electromotive force, and shaft voltage is formed. When the shaft voltage reaches a certain value, an oil film is broken down, and shaft current is formed through the bearing inner ring, the bearing roller, the bearing outer ring, the bearing seat and the like. If the metal of the generator bearing is directly contacted without an insulating oil film, the shaft current can continuously pass through the bearing, but the shaft current is smaller, and the bearing is not greatly influenced. Generally, oil film lubrication is adopted for a generator bearing, an extremely thin oil film is formed between an inner ring and an outer ring of the bearing and a roller, and the oil film is an insulator, so that a voltage difference exists between a rotating shaft of the generator and a bearing seat, a structure similar to a capacitor is formed, and shaft current cannot be formed. However, as time becomes longer, the rotating shaft of the generator accumulates charges, the voltage difference becomes larger and larger, and when the shaft voltage exceeds the breakdown voltage of the oil film, the oil film is broken down by current to form a closed loop. Because the rotating shaft, the bearing and the bearing seat are all made of metal, the loop resistance is very small, even if the shaft voltage is only tens of volts, the area of a breakdown area is small, and therefore, the shaft current with extremely high current density can be generated at a moment of breakdown. Although the duration of the shaft current is short, on one hand, the breakdown can instantaneously destroy an oil film, so that metal between the inner ring and the outer ring of the bearing and the rolling body is in direct contact, and the abrasion is accelerated. On the other hand, the contact surface of the oil film breakdown part of the inner ring and the outer ring of the bearing and the rolling body is small, and the shaft current is large, so that high temperature can be generated instantly, burn is easily caused, and the service life of the bearing is shortened. In the past, the generator bearing has the phenomenon of electric erosion, and the operation and the service life of the generator are influenced.

To avoid damage to the generator bearings from shaft currents, there are generally two solutions. The first method is to connect a carbon brush on a rotating shaft of a generator to guide shaft current out and avoid breakdown of a bearing oil film, but the carbon brush needs to be replaced periodically in the method, and when the rotating shaft is longer and the carbon brush is far away from the generator bearing, the voltage difference between the generator bearing and the ground is still higher, and the risk of breakdown of the generator bearing oil film still exists; in addition, if the generator bearing adopts oil injection lubrication, a carbon brush cannot be installed nearby, otherwise, dust abraded by the carbon brush enters the oil. The other method is to adopt an insulating bearing, and an insulating material coating is added on the inner ring side or the outer ring side of the generator bearing to thoroughly insulate and block, so that the generator bearing cannot form shaft current; however, for heavy duty bearings, the insulating material coating of the outer race may not withstand excessive external loads and may be damaged, resulting in bearing runout. In addition, the cost of the insulated bearing is also high. Therefore, the insulation bearing is not very suitable for bearing a wind generating set with large load and long service life.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the not enough among the prior art, provide a wind turbine generator non-contact axle current initiative release, through arranging external most advanced conductive needle near the generator bearing and the epaxial induced voltage ring of generator commentaries on classics between external voltage for when axle voltage does not exceed bearing oil film breakdown voltage, just appear most advanced conductive needle and the induced voltage ring between being punctured, the axle current is from this release.

In order to achieve the above object, the present invention provides a technical solution: a non-contact shaft current active release device of a wind turbine generator comprises a power-on ring, a power-on pin and an adjustable voltage source; the electricity leading ring is installed on a rotating shaft of the generator and close to a bearing of the generator, the tip end of the electricity conducting needle is close to and points to the electricity leading ring, the pin end of the electricity conducting needle is electrically connected with the input end of the adjustable voltage source through a wire, and the output end of the adjustable voltage source is grounded.

Further, the generator comprises a rotating shaft, a bearing and a bearing seat; the bearing is provided with two bearings which are respectively arranged at two ends of the rotating shaft and comprise a bearing inner ring, a bearing roller and a bearing outer ring, the bearing roller is arranged between the bearing inner ring and the bearing outer ring, the bearing inner ring is connected with the rotating shaft, the bearing outer ring is matched with the bearing seat, and the bearing seat is grounded.

Further, the electricity-leading ring is a low-resistance electricity-leading ring.

Further, the electricity-leading needle is high temperature resistant electricity-leading needle.

Compared with the prior art, the utility model, have following advantage and beneficial effect:

1. the installation position of the utility model is close to the bearing, which can not generate too large pressure drop, and avoid that the pressure drop of the path is too large and the voltage difference enough to break through the bearing oil film is still accumulated as the carbon brush is too far;

2. the utility model has the advantages that the carbon brush does not need to be replaced due to non-contact and non-abrasion, does not pollute oil, is too tight to be mounted on a bearing compared with a carbon brush scheme, and can pollute the oil due to abrasive dust generated by abrasion of the carbon brush when oil spraying lubrication is adopted, and the carbon brush needs to be replaced periodically;

3. the utility model discloses have the universality, need not change generator bearing type model, or do any change to generator bearing itself, compare in insulating bearing, all more have an advantage in intensity, life-span and the cost of primary generator bearing.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic diagram of a generator shaft and bearing system.

Fig. 3 is a generator equivalent circuit diagram based on the present invention.

Fig. 4 is a generator shaft voltage variation graph according to the present invention.

Detailed Description

The present invention will be further described with reference to the following specific embodiments.

Referring to fig. 1, the non-contact shaft current active release device for the generator of the wind turbine generator provided by the embodiment includes a power ring, a power pin and an adjustable voltage source, and the device includes two groups of active release devices respectively installed at the front end and the rear end of a rotating shaft 4 of the generator;

in the shaft current active release device positioned at the front end of a rotating shaft 4 of a generator, a power guiding ring 1a is arranged at the front end of the rotating shaft 4 and is close to a generator bearing 5a positioned at the front end of the rotating shaft, the needle tip end of a conductive needle 2a is close to and points to the power guiding ring 1a, the needle pin end of the conductive needle 2a is electrically connected with the negative electrode of an adjustable voltage source 3a through a lead, and the positive electrode of the adjustable voltage source 3a is grounded; in the shaft current active release device positioned at the rear end of a rotating shaft 4 of a generator, a leading ring 1b is arranged at the rear end of the rotating shaft 4 and is close to a generator bearing 5b positioned at the rear end of the rotating shaft 4, the needle tip end of a conductive needle 2b is close to and points to the leading ring 1b, the needle foot end of the conductive needle 2b is electrically connected with the positive electrode of an adjustable voltage source 3b through a lead, the negative electrode of the adjustable voltage source 3b is grounded, wherein the leading ring is made of low-resistance conductive metal, and the conductive needle is made of high-temperature-resistant conductive metal; through the two groups of shaft current active release devices, the shaft current can be actively released no matter the shaft voltage is at a high level or a low level.

Referring to FIG. 2, a schematic diagram of a generator shaft and bearing system is shown. The generator comprises a rotating shaft 4, a bearing and a bearing seat 6; the bearing has two to install respectively in the front and back both ends of pivot 4, is front bearing and rear bearing, and both all include bearing inner race 501, bearing roller 502 and bearing outer lane 503, bearing roller 502 sets up between bearing inner race 501 and bearing outer lane 503, bearing inner race 501 is connected with pivot 4, bearing outer lane 503 and bearing frame 6 cooperation, bearing frame 6 ground connection. Wherein, the bearing oil film forms a very thin insulating layer between the bearing inner ring 501 and the bearing roller 502, and between the bearing roller 502 and the bearing outer ring 503, and the generator rotating shaft 4 and the bearing seat 6 can not conduct the shaft current at this time.

Referring to fig. 3, which is a diagram of an equivalent circuit of a generator based on an active shaft current release device, C1 is a front bearing equivalent capacitor, C2 is a front tip equivalent capacitor, C3 is a rear bearing equivalent capacitor, C4 is a rear tip equivalent capacitor, U1 is an adjustable voltage source near a front bearing, and U2 is an adjustable voltage source near a rear bearing; the bearing and the bearing oil film are regarded as a bearing equivalent capacitor, the electricity leading ring and the conducting pin are regarded as a tip equivalent capacitor, and when the zero voltage of the shaft and the grounding is greater than the breakdown voltage of the bearing equivalent capacitor, the bearing oil film breaks down to form shaft current instantly.

The principle of the utility model lies in that the conductive needle is supplied with power by the adjustable voltage source, the voltage difference at the two ends of the equivalent capacitance of the tip end is increased, and the tip end of the conductive needle can increase the electric field intensity nearby, so that the equivalent capacitance at the tip end is easier to be punctured, and in addition, the conductive needle is also very close to the leading ring, which is also beneficial to be punctured; as long as the equivalent capacitance of the tip is punctured to form shaft current in advance compared with the equivalent capacitance of the bearing, the bearing is protected from shaft current, and the occurrence of electric corrosion damage is avoided. Different from a common capacitor breakdown variable path, after the bearing equivalent capacitor and the tip equivalent capacitor are broken down instantly to generate shaft current, the voltage difference is rapidly reduced, then the initial state is rapidly recovered, and the equivalent capacitor condition is changed back again.

Referring to fig. 4, a graph of a change in shaft voltage of a generator based on an active shaft current release device is shown, where a is a breakdown voltage difference between a conductive pin and a current-carrying ring at a front bearing, b is a front bearing oil film breakdown voltage, c is a shaft voltage change curve, d is a rear bearing oil film breakdown voltage, e is a breakdown voltage difference between a conductive pin and a current-carrying ring at a rear bearing, f is a conductive pin voltage at a rear bearing, and g is a conductive pin voltage at a front bearing; the voltage variation range of the ground voltage on the rotating shaft is between-15V and +15V, the breakdown voltage difference of the bearing is +12V or-12V, the voltage difference of the front bearing conductive pin to the ground is-5V, and the voltage difference of the rear bearing conductive pin to the ground is +5V. The breakdown voltage difference between the conductive pin and the electricity leading ring is 10V, and the following 3 conditions exist:

case 1 no discharge: when the shaft voltage is between-5V and +5V, the shaft voltage is smaller than the bearing breakdown voltage and the conductive needle breakdown voltage, so that the breakdown condition cannot exist, and the shaft can normally work;

case 2 front bearing discharge: when the shaft voltage is higher than or equal to +5V, the voltage of the front bearing conductive pin is-5V, the voltage difference between the front bearing conductive pin and the front bearing conductive pin is higher than 10V and is more than or equal to the breakdown voltage between the conductive pin and the electricity leading ring, so that breakdown occurs, and the shaft current active releasing device releases the shaft current to protect the front bearing. Since the oil film breakdown voltage of the front bearing is 12V, the shaft current is released when the shaft voltage reaches 5V, so that the oil film breakdown of the front bearing cannot occur. After the shaft current is released, the shaft voltage is instantly changed back to be near zero voltage, and the shaft voltage continues to be slowly accumulated again;

case 3 rear bearing discharge: similarly, when the shaft voltage is lower than or equal to-5V, the voltage of the rear bearing conductive pin is +5V, the voltage difference between the rear bearing conductive pin and the rear bearing conductive pin is higher than 10V and is more than or equal to the breakdown voltage between the conductive pin and the electricity leading ring, so that breakdown occurs, the shaft current active release device releases the shaft current, and the rear bearing is protected; and the oil film breakdown voltage of the rear bearing is +/-12V, so that the oil film breakdown of the rear bearing cannot occur, the shaft voltage returns to the vicinity of zero voltage after the shaft current is released, and the shaft voltage continues to be slowly accumulated again.

Without the shaft current release device, when the shaft voltage exceeds the breakdown voltage of the oil film of the bearing, the bearing generates the shaft current, and the electric erosion damage is generated for a long time.

The above-mentioned embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, so that all the changes made according to the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims (4)

1. The utility model provides a wind turbine generator non-contact axle current initiative release which characterized in that: the device comprises an electrifying ring, an electrifying needle and an adjustable voltage source; the electricity leading ring is installed on a rotating shaft of the generator and close to a bearing of the generator, the tip end of the electricity conducting needle is close to and points to the electricity leading ring, the pin end of the electricity conducting needle is electrically connected with the input end of the adjustable voltage source through a wire, and the output end of the adjustable voltage source is grounded.

2. The active release device of non-contact shaft current of wind turbine generator according to claim 1, characterized in that: the generator comprises a rotating shaft, a bearing and a bearing seat; the bearing is provided with two bearings which are respectively arranged at two ends of the rotating shaft and comprise a bearing inner ring, a bearing roller and a bearing outer ring, the bearing roller is arranged between the bearing inner ring and the bearing outer ring, the bearing inner ring is connected with the rotating shaft, the bearing outer ring is matched with the bearing seat, and the bearing seat is grounded.

3. The active release device of non-contact shaft current of wind turbine generator according to claim 1, characterized in that: the electricity-leading ring is a low-resistance electricity-leading ring.

4. The active release device of non-contact shaft current of wind turbine generator according to claim 1, characterized in that: the conductive needle is a high-temperature resistant conductive needle.

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