DNV GL employs the following methods to obtain the required grid data:
- Power quality measurement
- Grid protection measurement: The grid protection system can be checked at the device itself or on a test bench with a test procedure run to obtain reaction times and values, e.g. under-voltage or over-frequency.
- Fault ride-through: A voltage dip unit and a system to measure voltage and current at different points inside the voltage dip unit, grid and device are installed at the device to measure its reaction to a grid fault.
- Electromagnetic compatibility: HSE regulations require a short-term manned measurement to be conducted to determine electromagnetic levels.
- Grid monitoring: A small grid surveillance device installed in the substation to monitor the site’s correct behaviour in the event of grid failure is regularly checked by DNV GL staff and details of high frequency data occurring during a grid failure reported to the client.
- Small devices: Electrical measurements similar to those for utility-scale devices can be conducted either in the field or on a test bench.