Test Bench for the Investigation of Resonances in Low-Voltage Grids

Inhalt:
Resonances are an increasing problem in low-voltage grids. By the growing amount of grid-connected power electronics, many loads are no longer having an (resistive-)inductive behaviour, but a (resistive-) capacitive behaviour, caused by the capacitive line filter, especially during low load periods. In combination with the inductive behaviour of e.g. transformers and cables, resonant circuits can occur, which can be excited by harmonic voltages. Furthermore, the afore mentioned decreasing number of resistive loads results in a decreasing natural damping of the resonance circuits which in turn can increase resonance problems additionally. Due to this reasons, the investigation of resonance phenomena as well as resonance damping (active via voltage source inverters) are getting more and more into the focus of academia and industry. This article describes the setup and the operation of a test bench for the investigation of resonances in low-voltage grids.