Comparison of impedance behavior of UVRT-Container with medium voltage grid simulator in case of unsymmetrical voltage dip

Abstract

1This paper presents the concept of electrical testing, such as under voltage ride through (UVRT) of wind turbines on test bench using Power Electronics Grid Simula-tor (PEGS). PEGS can emulate an artificial medium voltage grid up to 36kV. One of the PEGS capabilities is to add artificial series impedance to the voltage source in fa-vor of changing the virtual short circuit power at the point of common coupling (PCC). In order to verify the test bench UVRT tests it is essential to show if PEGS is capable to emulate same grid behavior and characteristics as UVRT-Container. Later, a com-parison of the simulation results of the developed PEGS test to the UVRT-Container test is presented. In case of a two-phase fault emulated by UVRT-Container, the im-pedance seen by the faulted and un-faulted phases are changed during the fault due to additional short circuit impedance connected to the grid. The aim of this paper is to show that the PEGS can emulate the impedance for each phase during unsymmet-rical faults.