GE 1.5 Yaw system

The purpose of the yaw system is to keep the nacelle facing into the wind. It does this two ways:

-Actively driving the nacelle into the wind. -Passively with the yaw puck assemblies.

When does the yaw system track wind?

-Begins tracking the wind at 2.2 m/s* (P6.01) or -Generator speed >100 rpm.

Faults

-Cable twisting left/right -yaw position at max turns -yaw tooth encoding malfunction -yawing wrong direction -wind vane/ano defect -yaw limit switch activated -yaw motor overtemp -yaw runaway

Yaw Brake System

-Hold the nacelle facing into the wind -Hold tension against the drive pinions to reduce noise and chatter from gear engagement -Consists of 12 puck assemblies -Active Brake System

Yaw sensors

-Inductive Sensors -The sensors send a pulse to the PLC via the WETA card and allow it to count the teeth of the slew ring

Yaw sensors allow the PLC calculate the....

-The exact position of nacelle in relation to north -Information for cable untwisting -If shadow casting limits have been exceeded

Three operational modes control the motors:

-Wind direction tracking -Cable untwisting -Manual Operation

Where can the yaw system prevent movement in the wind turbine?

-Yaw out of the wind to stop rotor movement -Yaw brake keeps the WTG pointed into the wind -Yaw motor brakes keep the yaw motors from turning

At what point does the WTG untwist when idling or spinning?

1.8 turns

At what point does the WTG untwist for all states other than extreme winds?

2 turns

At what wind speed does the WTG start tracking the wind?

2.2 m/s. Parameter could be increased due to foghorning

What temperature causes the turbine to fault

90 degrees celsius

What does the yaw drive exactly do?

A heavy duty pinion on the drive output shaft engages with the outer teeth of the slewing ring.

Yaw motor overtemperature

An on-site check is necessary to determine whether there is a fault in the PTC, the Thermistor relay or the PLC, or if the motors are really too hot. If so, the cause of overheating must be found, e.g. excessively high mechanical loading, etc.

24 VAC powers...

Ano/Wv heaters (stepped down from 230 VAC)

230 VAC

Brake release voltage

When is wind direction tracking deactivated?

Conversely it will be deactivated if the average wind speed is lower than the yaw start wind.

24 VDC P24SW

K1 and K2 coil voltage

Cable twisting left/right (P_YawCableTwistStopRevs) or P_YawCableTwistUnwindingRevs)

Nacelle is reversed automatically by the PLC.

690 VAC

Power to the yaw motors

At what point does the twist switch engage and stop the WTG from yawing altogether?

Storm shutdown - signal from anemometer showing winds over limit - PLC evaluates - shuts down WTG.

230 VAC powers...

T4- Power for Ano/Wv heaters

Wind center signal

Tells whether the angle between the wind direction and nacelle is positive or negative. Wind center signal is calculated based on wind vane direction input.

Yaw runaway (P_YawRunawayMax).

The yaw brake system (yaw friction system) is not working correctly. The electromagnetic brakes of the yaw motors are not working correctly.

Anemometer defect

Troubleshoot anemometer circuit. Check all connections. R&R anemometer.

Yaw position at max turns (P_YawCableTwistEndingRevs)

Troubleshoot possibly reset yaw to zero

Wind vane defect (P_NRGTypeWindVaneEnable)

Troubleshoot wind vane circuit. Check for loose connections. R&R wind vane.

When is wind direction tracking activated?

When the wind speed exceeds the yaw start wind speed or if the generator speed is greater than 100 rpm.

Wind direction tracking

Wind direction tracking is activated dependent on the wind center signal, which tells whether the angle between the wind direction and nacelle is positive or negative.

When will the PLC track the wind?

Wind speeds ≥ 2.2 m/s

Operation of the yaw system:

controlled by a wind direction sensor (wind vane) & corresponding software.

Over twist switch engages...

faults WTG and shuts off the yaw.

High winds untwist engages...

for one revouloution-EM and automatically untwists the WTG.

Slewing ring

part of a bearing with the slew ring part (the outer ring) mounted to the top of the tower with the moving (the inner ring) mounted to the bottom of the bedplate.

Yaw Tooth Encoding Malfunction

sensors faulty or dirty, incorrect adjustment, broken leads, fault in PLC module.

Yaw Drive

takes the high speed lower torque output of the motor and reduce the speed while increasing the torque proportionally

Low winds untwist engages...

to 0 degrees-EM and automatically untwists the WTG.

How does the yaw system interact Mechanically?

•Mechanically the yaw system interacts through the bedplate. -The yaw drives are mounted to the bedplate. -The bedplate via the pucks rides on the slewing ring -The slewing ring is mounted to the top of tower.

How does the yaw system interact electrically?

•The yaw system interacts electrically with other components through the PLC. -Wind vane/anemometer -Motor control -E-Stop locks out yaw commands by shutting off P24SW with 13K3

The PLC will continue to track the wind unless:

•There is a grid failure •The turbine is in manual yaw •The turbine is untwisting