The low-voltage (LV) grid undergoes a major transformation, due to the expansion of renewable energy sources (RES), local storage, LED lighting and other devices powered by switching power electronics. These introduce new power quality problems. Due to the switching power electronics, the grid voltage and current will contain, next to harmonic frequencies, an increasing content of power conversion harmonics (PCH) in a frequency range up to 150 kHz and above. Moreover, both RES, grid connected inverters (GCI) and loads comprise switching non-linearity’s with a non-negligible capacitive behaviour. Consequently, the behaviour of the grid evolves from resistive-inductive into resistive-capacitive, creating low impedance paths for the PCH. As a consequence, these harmonics circulate in the LV grid, causing several problems. In addition, due to these new loads, the LV grid is characterized by a continuously changing impedance behaviour, making predictability more challenging. The mutual interactions between switching devices and the grid modify the system behaviour and decrease the grid robustness and the reliability of devices. Moreover, dedicated signalling over the grid, i.e. power line communication (PLC) and ripple control (RC), are affected. The objective is to mitigate these high frequency (HF) interferences (2 – 150 kHz) in the LV grid, by using decentralised or built-in HF power quality filters.
The objective of the project can be summarized as:
Development of innovative and robust filter concepts to mitigate HF interferences in the LV grid, taking into account PLC signals & non-linear loads, with the goal to improve the performance and reliability of the grid.
The expected result is to improve the performance and reliability of the grid and simultaneously allow control communication e.g. PLC and RC for LV grid operations. This requires the development of an innovative and robust filter tailored to handle frequency disturbances in the 2 to 150 kHz domain under a dynamic changing grid impedance environment of nowadays and future LV grids.