Coordinated voltage control scheme for Flemish LV distribution grids utilising OLTC transformers and D-STATCOMs

The incorporation of on-load tap changers (OLTCs) in secondary distribution transformers has been proposed as alternative technology to prevent the violation of the voltage statutory limits in Flemish low-voltage (LV) distribution grids. Under high penetration levels of distributed generation (DG), this device can partly eliminate those violations increasing the voltage unbalances when independent tap-changing control per phase is applied. This presentation describes a coordinative scheme for the regulation of positive and negative sequence voltages utilizing OLTC transformers and distributed static synchronous compensator (D-STATCOM) devices. From the results, it was concluded that the proposed scheme can fully remediate the over-voltage violations via active power control and decrease the voltage unbalances considerably via reactive power management.