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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. [ABSTRACT FROM AUTHOR]

The rapid adoption of residential-scale photovoltaic (PV) systems in low-voltage (LV) networks combined with the falling prices of residential-scale battery energy storage (BES) systems is paving the way for a future in which customers could locally supply most of their energy needs. However, off-the-shelf (OTS) storage systems operate for the sole benefit of the customer (reducing grid imports). This means that charging might not occur during times of high PV generation, resulting in technical issues on LV and medium-voltage (MV) networks. This paper proposes an adaptive decentralized control strategy for residential-scale BES systems to reduce voltage and thermal issues whilst still benefiting customers. With this strategy, the power charging and discharging rates constantly adapt throughout the day based on clear-sky irradiance, PV generation, demand, and state of charge; significantly reducing reverse power flows and ensuring adequate storage capacity the next morning. A real Australian MV feeder with realistically modeled LV networks is studied using smart meter data. Results demonstrate that the proposed control strategy overcomes the limitations of the OTS BES. It is also shown that it can be as effective as an ideal optimization-based approach, being able to manage all technical issues without significantly affecting customers. [ABSTRACT FROM AUTHOR]

The growing adoption of residential photovoltaic (PV) systems around the world is presenting distribution network operators (DNOs) with technical challenges, particularly on low voltage (LV) networks. The need to mitigate these issues with simple yet effective measures in countries with high PV penetrations is likely to drive the adoption of limits on the very exports that affect this infrastructure. Defining the most adequate limit, however, requires understanding the tradeoffs between the technical benefits and the effects on PV owners. This paper proposes two methodologies: an optimal power flow (OPF) based technique to define the export limit that solves technical problems with minimal curtailment, and a Monte Carlo based analysis to investigate the spectrum of such tradeoffs considering different PV penetrations and export limits. A real U.K. residential LV network with 180 customers is analyzed using realistic 1-min resolution daily load and PV generation profiles across seasons. Results demonstrate that, for DNOs, the OPF-based approach is effective in determining the most technically adequate export limit. However, for policy makers, the spectrum of tradeoffs provided by the Monte Carlo approach can help defining export limits that reduce curtailment at the expense of partially mitigating technical issues. [ABSTRACT FROM AUTHOR]

• Services from DER will need to consider distribution network constraints. • Three core TSO-DSO coordination models are identified in the literature. • Main solution techniques to ensure distribution network integrity are identified. • Main gaps: 3-phase AC OPF, MV-LV networks and controllable network assets. • Scale and complexity of distribution networks requires distributed approaches. The volume of services procured by transmission system operators (TSOs) through distribution-connected resources, aka distributed energy resources (DER), has been increasing in recent years. Currently, distribution networks are assumed to be fully capable of dealing with the resulting power flows. However, this assumption will no longer be valid as the volume of DER services become significant. Therefore, distribution system operators (DSOs) need to have a more active role to ensure the integrity of the distribution network while facilitating DER services. To achieve this, adequate coordination between TSOs and DSOs is required. To help stakeholders understand the implications of different coordination models so they can be adopted or tailored to their needs, this paper identifies three core TSO-DSO coordination models from the many proposed in the literature, discussing the corresponding advantages, disadvantages and challenges. Furthermore, a mapping of the proposed solution techniques is carried out to identify research trends and gaps. [ABSTRACT FROM AUTHOR]

• Excess power from solar PV reduces aggregated net demand and causes the 'duck curve'. • Off-the-shelf batteries can reduce excess PV generation, but the extent is unknown. • Realistic bottom-up modeling provides more accurate aggregated net demands. • Commercially available off-the-shelf batteries still lead to 'duck curve' effects. • Adopting smart battery controllers can provide opportunities for long-term benefits. The declining cost of residential battery energy storage (BES) and photovoltaic (PV) systems enable customers to significantly reduce their energy dependency from the grid. By absorbing excess PV generation, BES systems could reduce impacts associated with the 'duck curve'. However, since off-the-shelf (OTS) BES systems are controlled for customer benefits, this absorption might be limited at times, resulting in similar duck curve effects. This work proposes a bottom-up modeling approach to demonstrate the system-level generation cost effects from residential BES systems. Using a modified IEEE 9-bus system with real anonymized smart meter data, results show that with the OTS BES control, the overall reduction in system net demand due to peak PV generation still occurs which leads to baseload generation shutting off, incurring additional costs. Alternatively, the adoption of smarter BES controls aimed at mitigating impacts on distribution networks by reducing PV exports can bring significant system-level generation cost reductions. [ABSTRACT FROM AUTHOR]