Page 20 - Industrial Plants

Fig 7 - The frequency adjustment function

the contrary Grid-forming inverter with an differences caused by fluctuations in generation and
independent internal frequency can establish grids loads. Adjustment is used to smooth this difference.
and strengthen operating grids. This contributes to In the event of an imbalance between generation
the Smart Digital Storage suitable for large RES and load, there is a variation in the frequency at
accommodation. which the speed regulators of the generators react
and with greater speed the storage systems for this
Frequency Regulation to support purpose. This function is even more important with
the grid a weak grid or in off grid applications because the
With RES penetration Storage is an essential tool for rapid change of sun and or wind could cause
respecting the quality of the service (frequency, unacceptable output variations of the power supply.
voltage) guaranteeing inertia and short-circuit
power: SAET had an important experience of this Integrated Minigrid
type (see Fig. 7) in Austria with EVN and Verbund. Microgrids are electricity distribution systems
containing loads and distributed energy resources,
The regulation is used to reconcile the instantaneous (such as distributed generators, storage devices, or

The function Grid Firming is implemented in the
application of Fig 8 as described below:
1. the EMS measures the real-time power
output of the wind farm
2. From this value the EMS calculates the
correction power output of the BESS to
smoothen the total output
3. A dead band is set in order to avoid BESS
active power exchange caused by minimal
fluctuations of the wind production

The total output (green) is significantly
smoothed. Without BESS the output would
have been the one of the wind farm (orange).

Fig 8 The frequency adjustment function

INDUSTRIAL PLANTS - May 2022
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