Control circuits

Taking into account IEC 61400-1:2005 Wind turbines - Part 1: Design requirements (EN 61400-1:2005); the design of the electrical system for the wind turbine must satisfy the requirements of IEC 60204-1, i.e. the wind turbine must include suitable devices to provide protection against those malfunctions in the wind turbine and the electrical grid to which it is connected that could result in unsafe conditions or states.

To address this requirement, it is recommendable to also operate control circuits as an IT system with insulation monitoring, as in this way insulation faults in a control circuit are detected at an early stage and the possible tripping of a fuse and the failure of the controller on a 2nd fault is prevented. The response value for an insulation monitoring device is set in the high kΩ range. This means, e.g., control errors due to insulation faults on the sensitive inputs of the PLCs can be prevented.