11.0 Maintenamce

92

The oil system should be checked for leaks and if it is equipped with a filter this should be replaced every year.

11.4Power Distribution System/Controls

Main Control Enclosure:

The panel should be inspected annually for burns, cracks and discoloration.

The relays should be inspected annually for burned out coils and contacts.

The calibration of the speed sensor circuit should be checked annually using a laptop computer and a programming cable to read the speed value into the PLC memory and by executing a rotor jog. The speed sensor signal frequency should be close to 1500 (50Hz) or 1800 (60Hz). Acceptable speed sensor signal frequency range lies between 1490 and 1510 (50 Hz) or 1790 and 1810 (60 Hz). If the signal frequency lies outside of this range see Appendix H for the calibration procedure.

Similarly, the anemometers and their circuits should be checked for faults.

Tripped circuit breakers should be checked for and if found AOC should be notified before resetting.

Dynamic Brake Capacitor Box:

The panel should be checked monthly for burns, cracks or discoloration, especially the heavy gauge wiring and the capacitors.

The fuses and indicating lights on the front panel of the power factor correction capacitor box should be checked. If any fuses have tripped, AOC should be notified before replacing them and restarting the machine.

Dynamic Brake Resistor Box:

The panel should be checked monthly for burns, cracks or discoloration.

The resistor coils should be checked for excessive oxidation.

The wiring should be checked for insulation damage.

For a large-scale installation, regularly needed maintenance items can be identified from an analysis of the maintenance records. A 5% sample of wind turbines can serve as a base to identify frequently needed items and determine their life expectancies. The analysis can include (but is not limited to):

Annual energy production figures for the sampled machines.

Resistance across each generator winding (minimum value 1.48 M-ohms (see IEEE Std 43-1974)).

Gearbox oil analysis for water and particulate contamination (metallic or other suspended abrasives).

Periodic inspection of main shaft, gears, bearings and other gearbox components, as well as generator rotor and bearings.

NOTICE: Use of the material contained in this document is subject to the warning on page Iv and the disclaimer on page v of this document.

DOC012R02

AOC 15/50 User Manual

Nov 2001

Page 100
Image 100
AOC 15 user manual Power Distribution System/Controls