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.

The energy transition comes along with an increase of voltage variations especially on the LV (Low Voltage) network due to photovoltaic (PV) generation influence. In the scope of the French smart grid demonstrator GreenLys, and in order to limit these variations, an OLTC (On Load Tap Changer) has been experimented in a secondary substation in Lyon since November 2015. It has been associated through PLC (Power Line Communication) with several voltage sensors wisely placed on the LV network to get a precise vision of the voltage on the network fed by the transformer. This paper describes the voltage regulation infrastructure implemented and its main outcomes.

ERDF "ERABLE" project aims at creating value from the large amount of data from smart meters in terms of distribution network planning and power quality improvement. The prototype presented in this paper, consists in automatically running a "playback", day after day, of the system. This is made possible by projecting the individual measured load curves on the network models imported from the ERDF GIS into DIgSILENT PowerFactory. The tool builds dashboards and "snapshots" of each LV network element enabling network resizing or phasebalancing for voltage quality enhancement purpose. The system was used during the 2012 winter on 350 LV networks processing 11 000 individual load curves. Phasebalancing operations are currently being handled on the field.

This study contemplates the possibility of estimating in near real-time the extreme voltages (minimum and maximum phase-to-neutral voltages) in a low voltage (LV) network using some, but as little as possible, advanced metering infrastructure (AMI) data. The main target application is to control an on-load tap changer at a secondary substation (medium voltage/LV substations) so as to maintain adequate voltage in the entire downstream LV network. The authors focus on the practical problem that consists in choosing the customers whose (AMI-based) voltage measurements will be used as inputs to the voltage control. They propose a method for the selection of customers that is based solely on statistical load profiles (without the need to resort to past AMI data) and they assess it using real-world data from 38 different French urban and semi-urban LV networks. The authors' results show that working with simple load profiles instead of large amounts of past AMI data is acceptable, and that in most cases, choosing only a set of about ten customers at most is sufficient to guarantee an almost negligible level of error in the estimation of the minimum and maximum voltages in the LV network.

Optimising the normal opened points of its MV feeders allows ERDF, the main French distribution network operator, to reduce its losses to approximately 2%, while adopting a summer/winter scheme for its (V)HV/MV substations should allow another rapid reduction of 2% but at the cost of a degradation in supply quality whose acceptability remains to be discussed. The adoption of new MV/LV transformers will also allow new and significant savings whose effects will appear progressively. The experiments and complimentary studies to come will allow ERDF to judge if it is opportune to modify the voltage system to operate the MV network at the lowest possible voltage level with the prospect of gains in the order of 1%. The connection of decentralised generation is shown to be unfavourable overall in terms of losses, except in the case of a connection very close to a (V)HV/MV substation.