In power system, there are three modes of microgrid control. 1)Master-slave mode 2)Peer-to-peer mode 3)Combined mode

1. Distributed Generation and
Micro grid
ASSIGNMENT
• Submitted By,
Bhavisha Patel

2. TOPIC
 Write a Note on Different Controlling Modes of Micro
grid.

3. Micro grid control modes
Master – Slave Mode
Peer to Peer Mode
Combined Mode
1
2
3

4. Master - Slave Mode
• In master–slave mode, different DGs within a micro grid are controlled with
different methods and assigned with different functions, as shown in Figure 1.
One or more DGs act as the master while the others as the slave. In grid-
connected operation, all DGs are under P/Q control.
• In islanded operation, the master DG switches to V/f control to provide voltage
and frequency reference for other DGs.

5. Figure 1: Architecture of micro grid under master–slave control

6. • To enable quick transfer between control modes, the following forms of DG
could be used as master DGs:
1. DGs of randomness such as PV and wind;
2. ES, Micro-turbine, fuel cell, and other stable and easily controlled DGs; and
3. DG + ES, for example, PV + ES or PV + fuel cell.
• The third form is advantageous over the first two in that it can make best use
of quick charge and discharge functions of ES and the capability of DGs in
maintaining islanded operation of the micro grid for an extended time.

7. Peer-to-peer mode
• Peer-to-peer mode is a control strategy based on ideas of “plug-and-play” and
“peer-to-peer” used in power electronic technologies. In this mode, all DGs in
the micro grid are equal and there is no master or slave DG.
• All DGs participate in regulation of active power and reactive power in a preset
control mode to maintain stability of the system voltage and frequency.
• Droop control is adopted in the peer-to-peer mode, with the architecture shown
in Figure 2. In this mode, all DGs under droop control participate in voltage and
frequency regulation of the micro grid in islanded operation.

8. Figure 2: Architecture of micro grid under peer-to-peer control.

9. Combined mode
• Master–slave control and peer-to-peer control have advantages and
disadvantages. A micro grid may contain multiple types of DGs, such as DG of
randomness (e.g., PV and wind), or stable and easily controlled DG or ES
(e.g., micro turbine and fuel cell).
• Control characteristics differ greatly for different types of DG. Apparently, a
single control mode cannot meet the operation requirements of a micro grid. In
view of the dispersive DGs and loads within a micro grid, different control
strategies may be adopted for different types of DGs, that is, master–slave
control and peer-to-peer control could be used in conjunction in a micro grid.