The Needs to Control Microgrids.
Technical needs to control the complex Microgrids
National reserves
Grid operators (Elia) have a cascade of different reserves to balance the grid, leading to different demand-response programs offered by a number of aggregators in Belgium.
- R1: primary reserve (Frequency Containment Reserve).
- R2: secondary reserve (automatic frequency recovery reserve aFRR)
- R3: Tertiary reserve (manual frequency recovery reserve mFRR)
European Grid Code Requirements
If the Elia voltage > the maximum allowable value (defined by the Grid Code) then the decentralized generation plant must reduce the Elia voltage by absorbing reactive power (according to a curve)
If the Elia grid voltage drops below a certain value (defined by the Grid Code), the decentralized generation plant must increase the Elia voltage by increasing reactive power.
Important to know: the frequency in Europe is unique to the 28 member countries and is very stable, but the voltage is highly variable over time and depending on location and therefore must be permanently adjusted.
Microgrid must be able to operate in all operating modes
- Grid connected operation of the microgrid (driven by various parameters such as government incentives, energy trading, carbon footprint, etc.).
- Island mode (in case of grid quality problems, congestion, capacity tariffs, ....)
- The challenge for automation is to switch between Net-connected and Island mode of operation
- Controlled switching from network operation to island operation of hybrid microgrid
- Uncontrolled switching from grid-connected to islanded operation of hybrid microgrid due to disconnection from main distribution
- Uncontrolled switching from grid-connected to islanded operation of the hybrid microgrid due to ground faults in the grid
Grid parallel versus islanding of microgrids
Net coupled operation of Microgrid:
- Active power control + reactive power control
- Island mode of Microgrid
- Frequency control, Voltage control, active load distribution, reactive load distribution
- The challenge is to switch asset control of all production and storage assets of the Micron network between different control modes and create a fast-response load shedding system to prevent blackouts.
- Need for an integrated automation platform for control:
- Power production/storage act
- Power distribution system with intelligent load control