Conservation Voltage Reduction (CVR) has been traditionally applied adopting moderate settings at primary substations and when distributed generation was uncommon. However, as new infrastructure is deployed across Europeanstyle MV and LV networks, driven by increasing photovoltaic (PV) penetration levels, the opportunity arises to develop more advanced CVR schemes. This work proposes a centralized, threephase AC OPF-based CVR scheme that, using monitoring, onload tap changers (OLTCs) and capacitors across MV and LV, actively manages voltages to minimize energy consumption, even with high PV penetration, whilst considering MV-LV constraints. To tackle scalability issues brought by discrete variables, a twostage approach is proposed to solve the OPF as a non-linear programming problem (relaxing integer variables). A process that continuously checks customer voltages is adopted to trigger the optimization only when needed. Moreover, CVR benefits are not only quantified at a network level but also for customers, providing useful insights to policy makers. The proposed control is assessed using a realistic, unbalanced UK residential MV-LV network (2,400+ customers) with high PV penetration, and 1-min resolution time-varying profiles and load models. Results demonstrate that the proposed control effectively coordinates voltage regulation in MV and LV levels throughout the day, minimizing energy imports for all customers.

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The number of residential consumers with solar PV and batteries, aka prosumers, has been increasing in recent years. Incentives now exist for prosumers to operate their batteries in more profitable ways than self-consumption mode. However, this can increase prosumer exports or imports, resulting in power flows that can lead to voltage and thermal limit violations in distribution networks. This work proposes a framework for Distribution Network Operators (DNOs) to ensure the integrity of MV-LV networks by using dynamic operating limits for prosumers. Periodically, individual prosumers send their intended operation (net exports/imports) as determined by their local control to the DNO who then assesses network integrity using smart meter data and a power flow engine. If a potential violation is detected, their maximum operating limits are determined based on a three-phase optimal power flow that incorporates network constraints and fairness aspects. A real Australian MV feeder with realistically modelled LV networks and 4,500+ households is studied, where prosumers' local controls operate based on energy prices. Time-series results demonstrate that the proposed framework can help DNOs ensure network integrity and fairness across prosumers. Furthermore, it unlocks larger profitability for prosumers compared with the use the 5kW fixed export limit adopted in Australia.

Distributed energy resources (DER), such as, photovoltaic systems and batteries, are becoming common among households. Although the main objective is reducing electricity imports (bills), they could also provide system-level services via an aggregator. However, the more DER provide services, the more important is ensuring that the corresponding operation does not result in network issues. To help DER aggregators understand the implications of network constraints, an AC optimal power flow-based methodology is proposed to quantify the effects that three-phase low voltage (LV) and medium voltage (MV) network constraints can have on the volume of services that can be provided for a given horizon, and the potential benefits from using DER reactive power capabilities. Using a convex multi-period formulation that avoids binary variables for batteries and incorporates voltage-dependent load models, the methodology maximizes DER exports (services) for service-related periods and household self-consumption for other periods (reducing bills). Different service periods are assessed to explore the extent of services throughout the day. Results using a realistic UK MV-LV network with 2400+ households, show that aggregator services can be highly overestimated when neglecting MV-LV network constraints, are influenced by voltage-demand load characteristics, and that exploiting DER reactive power capabilities can significantly unlock further services.

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