A New Strategy for Selection of Switching Instant to Reduce Transformer Inrush Current in a Single-phase Grid-connected Photovoltaic System

作者：Abdelsalam Hany A^*; Abdelaziz Almoataz Y

来源：Electric Power Components and Systems, 2015, 43(11): 1297-1306.

DOI：10.1080/15325008.2015.1027424

• switching instant selection
• transformer inrush current reduction
• grid-connected photovoltaic system
• total harmonic distortion

Photovoltaic energy integration with the power system is increasing with the lack of fossil resources and developments in photovoltaic technology. Magnetizing inrush current occurs due to switching the transformer into service. Inrush current leads to shortage in the transformer lifetime and/or the operation of protection devices disconnecting the transformer. This article studies the impact of existing photovoltaic energy on the reduction of transformer inrush current. Photovoltaic power is utilized to reduce the inrush current by applying an opposite flux on the transformer, then connecting the transformer with the power network at a suitable switching instant of grid voltage waveform. The switching instant depends upon the flux produced in the transformer primary winding by the photovoltaic system. This article introduces a new strategy to determine the switching instant for reducing the transformer inrush current. The proposed method depends upon the monitoring of total harmonic distortion at different switching instants. The proposed method is appropriate for real-time applications. The proposed procedure is applied to a single-phase example and simulated in MATLABR2013a/SIMULINK (MathWorks, Natick, Massachusetts, USA). The simulation results show the suitable instant of switching to reduce the magnetizing inrush current and the corresponding total harmonic distortion.

• 出版日期2015-7-3