2024年3月16日发(作者：斐鸿禧)
IV – Part 1 7.8 Yaw System Chapter 7
GL 2010 Page 7-25
7.8 Yaw System
7.8.1 General
(1) This section applies to the yaw system of wind
turbines as described below. In the event of other
designs, the wording shall apply with the necessary
changes.
(2) The design of the yaw system shall be verified
for proper function in accordance with the system
concept.
(3) The torque necessary to make the nacelle track
the wind is provided by a yaw motor with the associ-
ated yaw gearbox (rotary drive). The torque is trans-
mitted by the yaw teeth from the yaw pinion to the
yaw bearing.
(4) The nacelle is supported on the tower head
either by a friction yaw bearing or by a roller yaw
bearing. The rotating of the nacelle around the tower
axis is usually braked either by a brake in the yaw
motor and/or by yaw brakes acting on a brake disc
fixed to the tower head or the nacelle.
(5) To exclude damages caused by alternating
stresses at the yaw teeth due to oscillating motions
around the tower axis, a constantly acting residual
brake torque should be applied, either by the innate
and load-dependent friction torque of the yaw bearing
or by an additional yaw brake system.
7.8.2 Assessment documents
(1) General information on the assessment docu-
ments to be submitted is given in Section 7.1.
(2) For the components of the yaw system, type
sheets, specifications and assembly drawings shall be
submitted.
(3) Assembly and sectional drawings, including the
associated parts lists and if applicable individual-part
drawings, shall be submitted together with a descrip-
tion explaining the functional principle of the yaw
system.
(4) The calculations (including input data for the
calculation, presentation of the results with the rele-
vant safety margins) for the verification of the com-
ponents of the yaw system shall be presented.
(5) For the evaluation of the yaw teeth, the individ-
ual-part drawings of the yaw pinion shaft and the yaw
bearing teeth are required, as well as individual-part
drawings of the planet carrier and the gearbox hous-
ing at the output of the yaw gearbox.
(6) The analysis of
−
the yaw gearbox teeth
−
the yaw bearing teeth
−
the load capacity considering the fatigue loads
−
the static strength against tooth breakage and
pitting
−
fatigue and static strength analysis for the output
shaft of the yaw gearbox and for the connecting
elements
of a yaw system with a yaw gearbox shall meet the
requirements posed within the documentation as per
Section 7.8.4.1.
7.8.3 Loads to be applied
(1) For the calculation of the loading of the yaw
system, the design loads as per Chapter 4 shall be
applied.
(2) For the fatigue strength analysis of the yaw
gears, the load duration distributions (LDD) and the
load spectra shall be used. A distinction shall be made
between operation with and without yawing. For
operation with yawing, innate and load-dependent
yaw bearing friction torque as well as gyroscopic
torque of the rotor at rated yaw and rotor speed shall
be considered in the fatigue strength analysis (see
Section 4.3.4.1, para 10.
(3) The static strength analysis – with and without
operation of the yaw system – shall be performed for
the design loads of the dimensioning load case as per
Chapter 4. If applicable, the following additional
dimensioning loads shall be considered:
−
the maximum torque of the yaw motor brakes for
the static strength analysis of the yaw gearbox,
the yaw bearing teeth and the connecting ele-
ments according to Section 7.8.4.2
−
If yaw motors are directly switched to the grid
without application of soft-start switches or fre-
quency converters, the static strength analysis for
the teeth and the shaft connections of the yaw
gearbox shall be performed by applying three ti-
mes the rated yaw motor torque. The occurrence
of peak torques at three times the rated motor
torque in direct-switched yaw motors shall be
Chapter 7 7.8 Mechanical Brakes and Locking Devices IV – Part 1
Page 7-26
considered also in the fatigue strength analysis of
the gears and their shaft connections.
(4) For the static strength analysis, an application
factor of K
A
= 1.0 is used.
(5) When determining the number of load cycles
or the load duration per tooth occurring during yaw-
ing, the specifications in Section 4.3.3.1 shall be used
as a basis. Operation of the yaw system shall be con-
sidered to occur during 10 % of the turbine’s service
life.
7.8.4 Verification of the yaw system
7.8.4.1 Yaw gearbox
(1) The gear load capacity calculation of the yaw
gearbox and yaw teeth shall be based on ISO
6336:2006.
(2) The calculation of the load capacity from the
fatigue loads shall be performed according to ISO
6336-6:2006 using the LDD or using an equivalent
torque derived from the LDD according to ISO 6336-
6:2006, Annex A. The Palmgren-Miner sum used in
the service life calculation shall be less than or equal
to 1.
(3) Furthermore, an analysis of the fatigue and
static strength against tooth breakage and pitting in
compliance with the safety factors according to Table
7.8.1 and Table 7.8.2 is also required.
(4) According to ISO 6336-5:2003, the predomi-
nant alternating load on the gears shall be considered.
A reduction factor of 0.7 for the respective S/N curve
shall be used. More favourable values may be used,
e.g. based on ISO 6336-3:2006, Annex B.
Table 7.8.1 Safety factors for the fatigue strength
analysis
Minimum safety
for yaw gearbox and yaw Gearbox
Yaw
bearing teeth
teeth
Surface durability S
H
1.0 1.10
Tooth root breakage S
F
1.15 1.25
GL 2010
Table 7.8.2 Safety factors for the static strength
analysis
Minimum safety
for yaw gearbox and yaw Gearbox
Yaw
bearing teeth
teeth
Surface durability S
H
1.0 1.10
Tooth root breakage S
F
1.1 1.2
(5) For the output shaft of the yaw gearbox and for
the connecting elements, a fatigue strength analysis
and a static strength analysis shall be submitted. The
analyses shall be performed in accordance with DIN
743, DIN 6892 and DIN 7190, or equivalent codes.
(6) Strength analyses for yaw gearbox housings
and planet carriers may be necessary (see Section
7.1.1.4).
7.8.4.2 Connecting elements
Strength analyses for bolted connections are neces-
sary wherever the bolts are essential to the distribu-
tion of forces (see Section 6.5).
7.8.4.3 Yaw bearing
(1) For the calculation and design of the yaw bear-
ing, reference is made to Section 7.3.
(2) The turbine manufacturer and/or the supplier of
the blade bearing shall verify that the surrounding
construction of the yaw bearing is adequate for the
function of the yaw bearing.
(3) The seals shall be so protected that they are not
damaged by the prevailing environmental conditions.
Note:
It should be possible to exchange the seal of the yaw
bearing in the installed condition.
7.8.4.4 Lubrication system
(1) It shall be shown that an adequate film of lu-
bricant is always provided on the flanks of the yaw
bearing teeth and also between the balls or rollers and
the track surface of the yaw bearing for all operational
modes of the wind turbine.
(2) For the teeth of the yaw bearing, a lubrication
system is mandatory in general. The functionality of
the lubrication system shall be documented (installa-
tion plan, lubrication intervals, lubricant distribution).
IV – Part 1 7.8 Yaw System Chapter 7
GL 2010
(3) Appropriate collecting reservoirs should be
provided to accommodate excess quantities of lubri-
cant from the yaw teeth as well as from the yaw bear-
ing.
7.8.4.5 Yaw brake
(1) Notes on the calculation of brakes are given in
Section 7.5.
(2) If a permanent application of a braking mo-
ment is required according to the system concept, the
function of the brakes shall also be ensured in the
event of failure of the power supply.
Page 7-27
7.8.4.6 Additional verifications
(1) In the case of systems with electrical actuating
yaw motors, Chapter 8 shall also be considered.
(2) For the verification of the hydraulic system,
Section 7.9 shall be considered.
Note:
According to section 4.5.4.3, para 3 the yaw system
may be applied for testing of the Load Relevant con-
trol and safety system Functions (LRF).
2024年3月16日发(作者：斐鸿禧)
IV – Part 1 7.8 Yaw System Chapter 7
GL 2010 Page 7-25
7.8 Yaw System
7.8.1 General
(1) This section applies to the yaw system of wind
turbines as described below. In the event of other
designs, the wording shall apply with the necessary
changes.
(2) The design of the yaw system shall be verified
for proper function in accordance with the system
concept.
(3) The torque necessary to make the nacelle track
the wind is provided by a yaw motor with the associ-
ated yaw gearbox (rotary drive). The torque is trans-
mitted by the yaw teeth from the yaw pinion to the
yaw bearing.
(4) The nacelle is supported on the tower head
either by a friction yaw bearing or by a roller yaw
bearing. The rotating of the nacelle around the tower
axis is usually braked either by a brake in the yaw
motor and/or by yaw brakes acting on a brake disc
fixed to the tower head or the nacelle.
(5) To exclude damages caused by alternating
stresses at the yaw teeth due to oscillating motions
around the tower axis, a constantly acting residual
brake torque should be applied, either by the innate
and load-dependent friction torque of the yaw bearing
or by an additional yaw brake system.
7.8.2 Assessment documents
(1) General information on the assessment docu-
ments to be submitted is given in Section 7.1.
(2) For the components of the yaw system, type
sheets, specifications and assembly drawings shall be
submitted.
(3) Assembly and sectional drawings, including the
associated parts lists and if applicable individual-part
drawings, shall be submitted together with a descrip-
tion explaining the functional principle of the yaw
system.
(4) The calculations (including input data for the
calculation, presentation of the results with the rele-
vant safety margins) for the verification of the com-
ponents of the yaw system shall be presented.
(5) For the evaluation of the yaw teeth, the individ-
ual-part drawings of the yaw pinion shaft and the yaw
bearing teeth are required, as well as individual-part
drawings of the planet carrier and the gearbox hous-
ing at the output of the yaw gearbox.
(6) The analysis of
−
the yaw gearbox teeth
−
the yaw bearing teeth
−
the load capacity considering the fatigue loads
−
the static strength against tooth breakage and
pitting
−
fatigue and static strength analysis for the output
shaft of the yaw gearbox and for the connecting
elements
of a yaw system with a yaw gearbox shall meet the
requirements posed within the documentation as per
Section 7.8.4.1.
7.8.3 Loads to be applied
(1) For the calculation of the loading of the yaw
system, the design loads as per Chapter 4 shall be
applied.
(2) For the fatigue strength analysis of the yaw
gears, the load duration distributions (LDD) and the
load spectra shall be used. A distinction shall be made
between operation with and without yawing. For
operation with yawing, innate and load-dependent
yaw bearing friction torque as well as gyroscopic
torque of the rotor at rated yaw and rotor speed shall
be considered in the fatigue strength analysis (see
Section 4.3.4.1, para 10.
(3) The static strength analysis – with and without
operation of the yaw system – shall be performed for
the design loads of the dimensioning load case as per
Chapter 4. If applicable, the following additional
dimensioning loads shall be considered:
−
the maximum torque of the yaw motor brakes for
the static strength analysis of the yaw gearbox,
the yaw bearing teeth and the connecting ele-
ments according to Section 7.8.4.2
−
If yaw motors are directly switched to the grid
without application of soft-start switches or fre-
quency converters, the static strength analysis for
the teeth and the shaft connections of the yaw
gearbox shall be performed by applying three ti-
mes the rated yaw motor torque. The occurrence
of peak torques at three times the rated motor
torque in direct-switched yaw motors shall be
Chapter 7 7.8 Mechanical Brakes and Locking Devices IV – Part 1
Page 7-26
considered also in the fatigue strength analysis of
the gears and their shaft connections.
(4) For the static strength analysis, an application
factor of K
A
= 1.0 is used.
(5) When determining the number of load cycles
or the load duration per tooth occurring during yaw-
ing, the specifications in Section 4.3.3.1 shall be used
as a basis. Operation of the yaw system shall be con-
sidered to occur during 10 % of the turbine’s service
life.
7.8.4 Verification of the yaw system
7.8.4.1 Yaw gearbox
(1) The gear load capacity calculation of the yaw
gearbox and yaw teeth shall be based on ISO
6336:2006.
(2) The calculation of the load capacity from the
fatigue loads shall be performed according to ISO
6336-6:2006 using the LDD or using an equivalent
torque derived from the LDD according to ISO 6336-
6:2006, Annex A. The Palmgren-Miner sum used in
the service life calculation shall be less than or equal
to 1.
(3) Furthermore, an analysis of the fatigue and
static strength against tooth breakage and pitting in
compliance with the safety factors according to Table
7.8.1 and Table 7.8.2 is also required.
(4) According to ISO 6336-5:2003, the predomi-
nant alternating load on the gears shall be considered.
A reduction factor of 0.7 for the respective S/N curve
shall be used. More favourable values may be used,
e.g. based on ISO 6336-3:2006, Annex B.
Table 7.8.1 Safety factors for the fatigue strength
analysis
Minimum safety
for yaw gearbox and yaw Gearbox
Yaw
bearing teeth
teeth
Surface durability S
H
1.0 1.10
Tooth root breakage S
F
1.15 1.25
GL 2010
Table 7.8.2 Safety factors for the static strength
analysis
Minimum safety
for yaw gearbox and yaw Gearbox
Yaw
bearing teeth
teeth
Surface durability S
H
1.0 1.10
Tooth root breakage S
F
1.1 1.2
(5) For the output shaft of the yaw gearbox and for
the connecting elements, a fatigue strength analysis
and a static strength analysis shall be submitted. The
analyses shall be performed in accordance with DIN
743, DIN 6892 and DIN 7190, or equivalent codes.
(6) Strength analyses for yaw gearbox housings
and planet carriers may be necessary (see Section
7.1.1.4).
7.8.4.2 Connecting elements
Strength analyses for bolted connections are neces-
sary wherever the bolts are essential to the distribu-
tion of forces (see Section 6.5).
7.8.4.3 Yaw bearing
(1) For the calculation and design of the yaw bear-
ing, reference is made to Section 7.3.
(2) The turbine manufacturer and/or the supplier of
the blade bearing shall verify that the surrounding
construction of the yaw bearing is adequate for the
function of the yaw bearing.
(3) The seals shall be so protected that they are not
damaged by the prevailing environmental conditions.
Note:
It should be possible to exchange the seal of the yaw
bearing in the installed condition.
7.8.4.4 Lubrication system
(1) It shall be shown that an adequate film of lu-
bricant is always provided on the flanks of the yaw
bearing teeth and also between the balls or rollers and
the track surface of the yaw bearing for all operational
modes of the wind turbine.
(2) For the teeth of the yaw bearing, a lubrication
system is mandatory in general. The functionality of
the lubrication system shall be documented (installa-
tion plan, lubrication intervals, lubricant distribution).
IV – Part 1 7.8 Yaw System Chapter 7
GL 2010
(3) Appropriate collecting reservoirs should be
provided to accommodate excess quantities of lubri-
cant from the yaw teeth as well as from the yaw bear-
ing.
7.8.4.5 Yaw brake
(1) Notes on the calculation of brakes are given in
Section 7.5.
(2) If a permanent application of a braking mo-
ment is required according to the system concept, the
function of the brakes shall also be ensured in the
event of failure of the power supply.
Page 7-27
7.8.4.6 Additional verifications
(1) In the case of systems with electrical actuating
yaw motors, Chapter 8 shall also be considered.
(2) For the verification of the hydraulic system,
Section 7.9 shall be considered.
Note:
According to section 4.5.4.3, para 3 the yaw system
may be applied for testing of the Load Relevant con-
trol and safety system Functions (LRF).