Abstract:
Power systems are becoming more vulnerable to different faults due to high penetration
of various renewable energy based distributed generators known as inverter based distributed generator (IBDG). It has become a great challenge to keep the system stable
and to keep the fault current at a manageable range during a short circuit fault. High
fault current insists system designer to install high rated protection equipments which
increases the overall cost of the system. While connecting an IBDG system to the grid,
it’s protection scheme must be considered because of this fault current problem. In this
work, a bridge type fault current limiter (BFCL) with a proper control of the whole system has been proposed as a solution to the high fault current problems of IBDG systems.
The BFCL is connected to the AC side of IBDG system and a proper controller is designed and implemented to control the reactance of BFCL. Voltage at point of common
coupling (PCC) is used as input to the BFCL activation controller. Outer controller loop
is proposed to control the DC link voltage of IBDG whereas an inner current controller
is designed to control the power exchange between AC and DC side of IBDG. Both
the balanced and unbalanced faults are applied in the AC side of the IBDG system to
demonstrate the effectiveness of the proposed controller. Finally the proposed strategy is
compared with series dynamic braking resistor (SDBR) and conventional method to see
the effectiveness of the proposed strategy.