Dynamic Modeling of Microgrid
for Grid Connected and Intentional Islanding Operation
ABSTRACT:
Microgrid is defined as the cluster of
multiple distributed generators (DGs) such as renewable energy sources that
supply electrical energy. The connection of microgrid is in parallel with the
main grid. When microgrid is isolated from remainder of the utility system, it
is said to be in intentional islanding mode. In this mode, DG inverter system
operates in voltage control mode to provide constant voltage to the local load.
During grid connected mode, the Microgrid operates in constant current control
mode to supply preset power to the main grid. The main contribution of this
paper is summarized as
1) Design of a network based
control scheme for inverter based sources, which provides proper current
control during grid connected mode and voltage control during islanding mode.
2) Development of an algorithm
for intentional islanding detection and synchronization controller required
during grid reconnection.
3) Dynamic modeling and simulation are
conducted to show system behavior under proposed method using SIMULINK.
From the simulation results using Simulink dynamic
models, it can be shown that these controllers provide the microgrid with a
deterministic and reliable connection to the grid.
KEYWORDS:
1.
Distributed
generation (DG)
2.
grid connected operation
3.
intentional islanding operation and islanding
detection
4.
Microgrid
5.
Synchronization
6.
voltage source converter (VSC)
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.1. Dynamic model of microgrid
with controller.
CONCLUSION:
Current
and voltage Control techniques have been developed for grid connected and
intentional islanding modes of operation using PI controllers. An intentional
islanding detection algorithm responsible for switching between current control
and voltage control is developed using logical operations and proved to be
effective. The reconnection algorithm coupled with the synchronization
controller enabled the DG to synchronize itself with the grid during grid
reconnection. The performance of the microgrid with the proposed controllers
and algorithms has been analyzed by conducting simulation on dynamic model
using SIMULINK. The simulation results presented here confirms the
effectiveness of the control scheme.
REFERENCES:
[1] L. Shi, M.Y.
Lin Chew. “A review on sustainable design of renewable energy systems,” science
direct journal present in Renewable and Sustainable Energy Reviews, Vol.
16, Issue 1, 2012, pp. 192–207.
[2] Q. Lei, Fang Zheng Peng, Shuitao Yang. “Multi loop control method for
high performance microgrid inverter through load voltage and current decoupling
with only output voltage feedback,” IEEE Trans. power. Electron, vol.
26, no. 3, 2011, pp. 953–960.
[3] J. Selvaraj and N. A. Rahim, “Multilevel inverter for grid-connected
PV system employing digital PI controller,” IEEE Trans. Ind. Electron., vol.
56, no. 1, 2009, pp. 149–158.
[4] I. J. Balaguer, Fang Zheng Peng, Shuitao Yang, Uthane Supatti Qin
Lei. “Control for grid connected and intentional islanding modes of operations
of distributed power generation,” IEEE Trans. Ind. Electron., vol. 56,
no. 3, 2009, pp. 726–736.
[5] R. J. Azevedo,
G.I. Candela, R. Teodorescu, P.Rodriguez , I.E-Otadui “Microgrid connection
management based on an intelligent connection agent,” 36th annual conference
on IEEE industrial electronics society, 2010, pp. 3028–3033.
