Sealed drive survives in wind turbines

The environment inside the cabinet of ABB's ACS800-77LC convertors is protected against dust, salt and extreme temperatures.

ABB's new drive for wind turbines combines advanced technology with totally enclosed cabinet construction.

The active and passive power-converting components and controlling electronics are liquid-cooled and enclosed by the cabinet construction with no air inlet or outlet openings.

This ensures that harsh ambient conditions do not infiltrate the cabinet and the electronics are stabilised.

The environment inside the cabinet is protected against dust, salt and extreme temperatures.

The ACS800-77LC convertors are part of ABB's wind turbine drive family.

"This convertor, which transfers AC power from the turbine generator through to the utility or transmission switchgear, also can be configured in various ways to optimise the number of power modules needed, as a function of the wind power or turbine speed/velocity to the generator", according to Ari Hedemaki, Product Line Manager, ABB Low Voltage Drives, North America.

"This modular, parallel convertor/inverter module configuration also enables wind turbine owners to optimise efficiency - and the system is completely redundant, in that the convertors will continue to operate at partial load, even if one of the inverter modules in the system goes offline for some reason".

From 1.5MW upwards, a full convertor system can be configured from two or three individual subsystems, which can be operated together, or one at a time.

This approach provides redundancy, as well as the freedom to choose the optimum location of the frequency convertor within a turbine system.

The liquid-cooled convertor is available for full convertor systems with permanent magnet or asynchronous generators and for doubly-fed asynchronous generators covering powers up to 5MW as standard.

Higher ratings are engineered according to customer demand.

The liquid-cooled convertor is equipped with the latest software and hardware developments to support the grid compliance of an individual turbine in any given locale.

Compliance with local grid codes is essential and highly dependant on the functionality of the frequency convertor.

ABB has extensive experience in providing convertors that support compliance of wind turbine with grid codes such as E.ON, R.E.E and FERC Order 661.

The new products are available with output ratings in the 1 to 5MW range.

As a result, the drive can be factory-installed by the turbine manufacturer or OEM, avoiding costly and time-consuming work on site.

Scalability means that the same modules can be used for different turbine designs, allowing easier maintenance and servicing and reduced training needs.

Direct Torque Control (DTC) is used to provide fast and accurate speed and torque control, without the need for pulse encoder feedback from the shaft.

DTC offers robust operating characteristics, high availability and reliability and high-quality output with low harmonics.

Thanks to DTC, the drives maintain good output quality in different wind conditions that vary from light to gusting and they also tolerate fluctuations in the power network.

The use of DTC also helps to decrease audible noise from the generator, which reduces the overall environmental impact.

Electrical and reactive power can be controlled independently.

PC-based tools make commissioning and service operations straightforward.

In addition to the normal fieldbus communications options, a built-in intelligent Ethernet module permits remote maintenance, monitoring and even control.

Diagnostic routines can be performed via the internet or a telecoms line and the module can trigger alarms in the event of a malfunction.

Remote access helps to reduce maintenance costs and minimise downtime.

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