Low Voltage Ride Through Controller for a Multi-Machine Power System Using a Unified Interphase Power Controller

Abstract

In recent years, grid-connected photovoltaic (PV) power generations have become the most extensively used energy resource among other types of renewable energies. Increasing integration of PV sources into the power network and their dynamic performances under fault conditions is an important issue for grid code requirements. In this paper, a PV source as a unified interphase power controller (UIPC) is used to enhance the low voltage ride through (LVRT) and transient stability of a multi-machine power system. The suggested PV-based UIPC consists of two series voltage inverters and a parallel inverter. The UIPC injects the required active and reactive power to prevent voltage drop under grid fault conditions. Accordingly, a dynamic control system is designed based on proportional-integral (PI) controllers for the PV-based UIPC to operate in both normal and fault conditions. Simulations are done using Matlab/Simulink software, and the performance of the PV-based UIPC is compared with the conventional unified power flow controller (UPFC). The results of this study indicate the more favorable impact of the PV-based UIPC on the system compared to UPFC in improving LVRT capabilities and transient stability.

Improving Transient Stability of a Synchronous Generator Using UIPC with a Unified Control Scheme

“…Here, the UIPC only protects the SCIG-based wind farm in case of faults occurring in the grid. A similar study [12] compares the efficacy of both UIPC and UPFC in enhancing the LVRT capability of a sample grid, including PV generation with the occurrence of faults. Here, since the UIPC is connected in series with the PV farm to control its power flow, thus, the transient stability of the SGs was not investigated.…”