CN105240214A - Safety circuit for overspeed protection of wind turbine generating set - Google Patents

Abstract

The invention provides a safety circuit for overspeed protection of a wind turbine generating set. The safety circuit comprises three gyroscopes, a controller and an alarm relay, wherein the gyroscopes are uniformly distributed and installed on a hub and are in signal connection with the controller; the controller is in control connection with the alarm relay; and contacts of the alarm relay are in series connection with the safety circuit of a pitch-varying system of the wind turbine generating set. The safety circuit has the following advantages: whether a current fan is in an overspeed state is directly detected. A main control system is not required to detect overspeed and then send a command for feathering to the pitch-varying system any longer, so that the problem that feathering cannot be carried out correctly when a variable pitch is in an overspeed state and a runaway accident is caused due to virtual connection of circuits at slip rings of the fan or other positions or due to other disturbances is avoided.

Description

A kind of safety circuit for Wind turbines overspeed protection

Technical field

The invention belongs to aerogenerator unit safe technical field, especially relate to a kind of safety circuit for Wind turbines overspeed protection.

Background technique

Overspeed protection is the important ring in aerogenerator unit safe chain, its objective is to prevent blower fan generation driving, causing blade broken, and blower fan such as to topple at the severe safety problem.

In the prior art, it is generally by being installed on main shaft that Wind turbines detects hypervelocity, the encoder of high speed shaft or generator afterbody detects Transmitted chains rotating speed, and when this rotating speed exceedes a certain safe threshold, Wind turbines can be communicated by master control system or hardwire theft-resistant link chain circuit requirements pitch-controlled system carries out feathering.

But in actual motion, owing to no matter being communication between master control system and change oar or adopting hardwire theft-resistant link chain loop all can pass through slip ring, when there is slip ring carbon brush and slip ring bad connection is good or the fault such as the circuit virtual connection at other positions time, the feathering order likely causing pitch-controlled system not receive master control system sending, still normally drive oar to run, finally cause the too fast generation driving of rotation speed of fan.

Summary of the invention

In view of this, the present invention is intended to propose a kind of safety circuit for Wind turbines overspeed protection, correctly can not perform feathering to avoid the change oar caused because of circuit virtual connection or other interference because of blower fan slip ring or other positions when exceeding the speed limit.

For achieving the above object, technological scheme of the present invention is achieved in that

For a safety circuit for Wind turbines overspeed protection, comprise three and be uniformly distributed the gyroscope be installed on wheel hub, controller and alarming relay; Described gyroscope signal connection control device, described controller control connection alarming relay, the safety circuit of the pitch-controlled system self of the contact series access Wind turbines of described alarming relay.

Further, described controller performs following steps:

First, the hub rotation speed accekeration under the current rotating speed that reception gyroscope detects in real time is 4 ~ 20mA signal;

Afterwards, according to calibration value, 4 ~ 20mA signal is converted to corresponding tachometer value ω, described controller performs following computer program:

First average, if three gyroscope values of feedback of a certain moment are divided into I ₁, I ₂, I ₃, ask the mean value I of three values of feedback as follows:

$I=\frac{I1+I2+I3}{3}---\left(1\right)$

Again according to following formula, calculate the rotational speed omega of current correspondence:

$\mathrm{\ω}=\sqrt[2]{\frac{a1+(I-4)\×(a2-a1)/(20-4)}{r}}---\left(2\right)$

In formula: rotating speed acceleration parameter a corresponding when gyrostatic value of feedback is 4mA ₁, be rotating speed acceleration parameter a corresponding during 20mA ₂, the distance r of gyroscope distance hub centre, and over speed of rotation protection setting value ω ₀;

Afterwards, tachometer value ω and over speed of rotation are protected setting value ω ₀compare: as ω > ω ₀time, controller C drives alarming relay k break contact; As ω≤ω ₀time, controller C drives alarming relay K adhesive contact.

Further, described controller is arranged in pitch-controlled system.

Further, described three gyroscopes are uniformly distributed on the main shaft end face that is installed in wheel hub.

Relative to prior art, the present invention has following advantage:

(1) whether directly in wheel hub, detect current blower fan is in overspeed condition, and no longer need to detect to exceed the speed limit by master control system to send order request pitch-controlled system feathering again, whether pitch-controlled system oneself can detect blower fan and exceed the speed limit, avoid because of blower fan slip ring or other positions because of circuit virtual connection or other disturb the change oar caused correctly can not perform feathering when exceeding the speed limit and runaway accident occur; Thus improve the safety and reliability of fan operation;

(2) and adopt the hardware cost paid of the program significantly lower than the scheme of existing employing encoder, have more economical.

Accompanying drawing explanation

The accompanying drawing forming a part of the present invention is used to provide a further understanding of the present invention, and schematic description and description of the present invention, for explaining the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings:

Fig. 1 is the circuit theory diagrams of safety circuit described in the embodiment of the present invention;

Fig. 2 is the mounting point schematic diagram of gyroscope described in the embodiment of the present invention in wheel hub;

The processor flow chart that Fig. 3 is controller described in the embodiment of the present invention.

Embodiment

It should be noted that, when not conflicting, the embodiment in the present invention and the feature in embodiment can combine mutually.

Below with reference to the accompanying drawings and describe the present invention in detail in conjunction with the embodiments.

For a safety circuit for Wind turbines overspeed protection, as shown in Figure 1, comprise three and be uniformly distributed gyroscope s1, s2, s3 of being installed on wheel hub, controller C and alarming relay K; Described gyroscope s1, s2, s3 signal connection control device C, the safety circuit of the contact series access pitch-controlled system self of described controller C control connection alarming relay K, described alarming relay K.

During installation, gyroscope s1, s2, s3 being uniformly distributed according to position is as shown in Figure 2 installed in wheel hub, because gyroscope s1, s2, s3 are mutually 120 ° of distributions in wheel hub, adding and offsetting of the rotating speed acceleration therefore measured by them is subject to the impact of gravity accleration; The distance of gyroscope s1, s2, s3 distance hub centre point as parameter r by being set in the controller C of measure loop, for the current rotating speed that converts; Described controller C can be arranged in pitch-controlled system.

Described controller C performs following steps:

First, the hub rotation speed accekeration under the current rotating speed that reception gyroscope s1, s2, s3 detect in real time is 4 ~ 20mA signal;

Afterwards, according to calibration value, 4 ~ 20mA signal is converted to corresponding tachometer value ω, concrete, as shown in Figure 3, described controller C performs following computer program:

First average, if three gyroscope values of feedback of a certain moment are divided into I ₁, I ₂, I ₃, ask the mean value I of three values of feedback as follows:

$I=\frac{I1+I2+I3}{3}---\left(1\right)$

Again according to following formula, calculate the rotational speed omega of current correspondence:

$\mathrm{\ω}=\sqrt[2]{\frac{a1+(I-4)\×(a2-a1)/(20-4)}{r}}---\left(2\right)$

In formula: rotating speed acceleration parameter a corresponding when gyrostatic value of feedback is 4mA ₁, be rotating speed acceleration parameter a corresponding during 20mA ₂, the distance r of gyroscope distance hub centre, and over speed of rotation protection setting value ω ₀;

Afterwards, tachometer value ω and over speed of rotation are protected setting value ω ₀compare:

When this tachometer value ω exceedes the over speed of rotation protection setting value ω of setting ₀time, i.e. ω > ω ₀time, controller C drives alarming relay k break contact, because this contact is by the safety circuit of access pitch-controlled system self of connecting, when contact disconnects, pitch-controlled system is feathering immediately, avoids blower fan hypervelocity driving;

As ω≤ω ₀time, controller C drives alarming relay K adhesive contact, becomes oar and normally runs.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. for a safety circuit for Wind turbines overspeed protection, it is characterized in that: comprise three and be uniformly distributed the gyroscope be installed on wheel hub, controller and alarming relay; Described gyroscope signal connection control device, described controller control connection alarming relay, the safety circuit of the pitch-controlled system self of the contact series access Wind turbines of described alarming relay.

2. the safety circuit for Wind turbines overspeed protection according to claim 1, is characterized in that: described controller performs following steps:

First, the hub rotation speed accekeration under the current rotating speed that reception gyroscope detects in real time is 4 ~ 20mA signal;

Afterwards, according to calibration value, 4 ~ 20mA signal is converted to corresponding tachometer value ω, described controller performs following computer program:

First average, if three gyroscope values of feedback of a certain moment are divided into I ₁, I ₂, I ₃, ask the mean value I of three values of feedback as follows:

$I=\frac{I_1+I_2+I_3}{3}---\left(1\right)$

Again according to following formula, calculate the rotational speed omega of current correspondence:

$\mathrm{\ω}=\sqrt[2]{\frac{a1+(I-4)\×(a2-a1)/(20-4)}{r}}---\left(2\right)$

In formula: rotating speed acceleration parameter a corresponding when gyrostatic value of feedback is 4mA ₁, be rotating speed acceleration parameter a corresponding during 20mA ₂, the distance r of gyroscope distance hub centre, and over speed of rotation protection setting value ω ₀;

Afterwards, tachometer value ω and over speed of rotation are protected setting value ω ₀compare: as ω > ω ₀time, controller C drives alarming relay k break contact; As ω≤ω ₀time, controller C drives alarming relay K adhesive contact.

3. the safety circuit for Wind turbines overspeed protection according to claim 1, is characterized in that: described controller is arranged in pitch-controlled system.

4. the safety circuit for Wind turbines overspeed protection according to claim 1, is characterized in that: described three gyroscopes are uniformly distributed on the main shaft end face that is installed in wheel hub.