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MEDAL WINNERS

Vestas propelled medium-speed drivetrain technology into the onshore mainstream with its groundbreaking EnVentus platform announced in early 2019.

The first two variants have a rating of 5.6MW with rotor diameters of 150 and 162 metres, the former due to operate as a prototype soon.

The Danish manufacturer recognised the need for a global modular turbine architecture in response to market-driven conditions back in 2012.

The modular approach offered inherent advantages in standardisation and repetitive tasks for significant manufacturing cost savings.

The main principle of the EnVentus platform is the compact semi-integrated medium-speed drivetrain.

Other product-specific features include a modular main shaft front-flange with multiple bolt circles radiuses to accommodate various hub sizes, and a modular main-shaft housing adapter flange for mounting the two-stage planetary gearbox (with journal bearings) and PMG sub-assembly.

This allows matching various gearboxes with corresponding input torque levels and specific operating conditions. The fully sealed air-cooled PMG only contains the relatively cheaper and easier-to-obtain rare earth Neodymium for the magnets.

The V150-5.6MW is aimed at IEC S sites, and can be deployed at up to 8m/s mean wind speeds with a maximum turbulence level of 15%. Vestas claims an AEP improvement of around 17% over the yield of its V150-4.2MW turbine.

SILVER Enercon E-138 EP3

The EP3 platform is fundamental to Enercon’s ambitious technology transition, the design focusing on a cost-effective configuration optimised for mass, manufacturing, transport logistics, ease of installation, and lifetime costs.

A 3.5MW E-138 EP3 prototype was installed in February 2019, a few months after the E-126 variant, with a rapid ramp-up in production following immediately after.

EP3 innovations include a three-module concept, a cleverly segmented generator with a conceptual switch from "endless" multi-strand copper wires to pre-manufactured aluminium form coils. The E-138 operates at 690V instead of Enercon’s long-term 400V electrical system voltage, with an active power-electronic converter offering enhanced efficiency.

Set against the E-126 EP3 reference, head mass could be reduced by a further six tonnes to 250 tonnes through lowering generator volume and mass. An uprated 4.2MW E-138 is in development.

BRONZE Dongfang D4200-155

Dongfang Electric Wind Power Co (DEC) introduced high-speed geared turbines with DFIG in 2004, and direct-drive PMG from 2007.

The company boasts a comprehensive in-house production base for turbines, direct-drive generators and blades, which has expanded rapidly.

All its turbines for international markets are direct drive: 2.5MW and 3-4.5MW for onshore, 4MW, 7MW and 10MW for offshore.

The D4200-155 prototype was installed early in 2019 and forms part of the 4.XMW three-turbine platform, all featuring a fully enclosed active air-cooled outer rotor PMG.

Dongfang’s direct-drive track record since 2007 amounts to more than 1,200 operational turbines (mainly 2.5MW), and another 1,300 for delivery in 2019 and 2020.