Assessment of the MV/LV on-load tap changer technology as a way to increase LV hosting capacity for photovoltaic power generators

This paper assesses the use of voltage measurements obtained from advanced metering infrastructure (AMI) to control an on-load tap changer (OL1TC with five or nine tap positions) located at the secondary substation, with the aim of increasing the hosting capacity of the low voltage (LV) network for photovoltaic power generators. The future growth of photovoltaic power generators is simulated with and without OLTC on 631 real-world LV networks located in Lyon(**) (France) and we study the maximum growth before a constraint occurs. The results surprisingly show that, although all our test networks are taken from the same geographical area, there is a large variation from one LV network to the other regarding how the MV/LV OLTC affects their hosting capacity. Indeed, this hosting capacity may be increased significantly in a few networks while the gain is modest or non-existent in the others. Another important finding is that, for the networks we studied, the OLTC with nine tap positions does not substantially increase the hosting capacity when compared with the one with five tap positions.