Grid-connected distributed generation sources interfaced

with voltage source inverters (VSIs) need to be disconnected

the grid under: 1) excessive dc-link voltage 2) excessive ac

currents and 3) loss of grid-voltage synchronization. In this paper,

the control of single- and two-stage grid-connected VSIs in photovoltaic

(PV) power plants is developed to address the issue of

inverter disconnecting under various grid faults. Inverter control

incorporates reactive power support in the case of voltage sags

based on the grid codes’ (GCs) requirements to ride-through the

faults and support the grid voltages. A case study of a 1-MW

system simulated in MATLAB/Simulink software is used to illustrate

the proposed control. Problems that may occur during grid

faults along with associated remedies are discussed. The results

presented illustrate the capability of the system to ride-through

different types of grid faults.-Grid-connected distributed generation sources interfaced

with voltage source inverters (VSIs) need to be disconnected

the grid under: 1) excessive dc-link voltage　2) excessive ac

currents　and 3) loss of grid-voltage synchronization. In this paper,

the control of single- and two-stage grid-connected VSIs in photovoltaic

(PV) power plants is developed to address the issue of

inverter disconnecting under various grid faults. Inverter control

incorporates reactive power support in the case of voltage sags

based on the grid codes’ (GCs) requirements to ride-through the

faults and support the grid voltages. A case study of a 1-MW

system simulated in MATLAB/Simulink software is used to illustrate

the proposed control. Problems that may occur during grid

faults along with associated remedies are discussed. The results

presented illustrate the capability of the system to ride-through

different types of grid faults.