Visit windpowermonthlyevents.com for the latest on our upcoming conferences and webcasts

The Vestas V164 and drivetrain choice

DENMARK: Senior product manager Vestas V164-platform Anders Bach Andersen explained the main decision process behind the drivetrain choice, whereby initially three potential options were evaluated, and medium-speed geared emerged as the winner.

The choice for a rear-mounted generator is explained by O&M-preference for a modular design with high degree of ‘plug and play’ valid to all main and most minor components. Also at built in systems for separating and joining drivetrain components without requiring a jack-up vessel before commencing actual hoist operations and for securing components alignment.

The drivetrain selection process considered multiple aspects including Cost of Energy, time-to-market, expected customer preferences, technology maturity and market acceptance, and supply chain capacity and risk.

The evaluation’s baseline was a high-speed geared up scaling of the V112-3.0MW incorporating a four-stage gearbox. However, assessment showed it unlikely that the design would achieve preset reliability targets and was therefore deselected.

Second option was a direct drive system with separate main shaft, integrated bearing housing, and rear-mounted generator. Basic motivation was reducing the number of mechanical parts, but ‘to the expense’ of more electrical parts.

The third medium-speed geared concept design features a three-stage planetary gearbox with flanged connections between main shaft housing, gearbox and generator. This layout proved much more compact compared to baseline, by meeting comparable targets with direct drive regarding modular design and ease of main components exchange.

For these remaining options, direct drive and medium speed, a decision was made for a rear-mounted generator. This choiceis explained by O&M-preference for a modular design with high degree of ‘plug and  play’ valid to all main and most minor components. Also preferred were built in systems for separating and joining drivetrain components without  requiring a jack-up vessel before commencing actual hoist operations and for securing components alignmen.

The final business case is represented by a graph showing customer internal rate of return on investment (IRR; %) versus drivetrain replacement rate for direct drive versus medium-speed. The Vestas study main conclusions favour of medium speed, claiming:

  1. Medium speed offers the highest IRR if drive train replacement rates are assumed zero for both options;
  2. The difference in slope follows the assumption that a larger direct drive failure would require full generator exchange, whereas a medium-speed failure only requires replacement of the generator or gearbox;
  3. Only with a very high number of medium-speed replacements, direct drive offers higher IRR.

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Windpower Monthly Events

Search more than 4,500 companies in the Windpower Directory

Latest Jobs

[DAYS_LEFT] DAYS Subscribe Now

Left of your Windpower Monthly free trial

Your free trial Subscribe Now

to Windpower Monthly has expired