Davide Della Giustina

Use case analysis of real-time low voltage network management

Real-time low voltage network management is becoming possible thanks to massive smart meter rollouts, integration of them to distribution network management systems and utilization of distributed energy resources in distribution network management. Nowadays low voltage network management is emerging by integrating automatic meter infrastructure to centralized systems like SCADA/DMS. European project INTEGRIS is proposing a distributed approach based on hybrid and meshed communication. The paper is focused on low voltage network management use cases developed within the context of INTEGRIS and their ICT requirements to test the level of performance provided by the ICT architecture developed in the mentioned project.

Hybrid Communication Network for the Smart Grid: Validation of a Field Test Experience

The business of distribution system operators is rapidly evolving as the distribution grid is hosting more distributed energy resources. Technology for monitoring, control, and protecting the grid is progressively pervading the lower segment of the network. These changes require a performing communication infrastructure to enable data exchange among the control centers of the grid. The 7th Framework Program European Project INTEGRIS proposes a hybrid infrastructure-based on broadband power line (BPL), Wi-Fi, and fiber optics (FO)-to enable services for grid management. This mix of technologies provides a balanced tradeoff between investments and benefits, meeting most of the requirements of the smart grid. This paper investigates the technologies that could be adopted and describes the experimental assessment performed in an operational environment in Italy. Using this installation, transfer time, time synchronization accuracy, dependability, and throughput are evaluated and analyzed over a long-term campaign. Results show that the FO is the best communication media, able to provide a two-way latency of 3 ms (95 percentile), whereas BPL has a two-way latency of 57 ms (95 percentile -4 hops). Those results confirm that a careful selection of the technologies is required to satisfy requirements of smart grid.

Electrical distribution system state estimation: measurement issues and challenges

The distribution grid is the infrastructure that transports electrical energy generated by large plants that are long distances away to the final user. A typical distribution grid consists of High-to-Medium Voltage (HV/MV) transformation centers; the MV grid; Medium-to-Low Voltage (MV/LV) transformation centers; and the LV grid, both three-phase and single-phase. Residential and commercial customers are mainly connected to the LV, while large industrial facilities are connected to the MV.

Testing low voltage network state estimation in RTDS environment

The low voltage network operating environment is going through changes. The simultaneous introduction of intermittent renewable energy production and customer requirements for increased power quality and supply reliability are forcing utilities to rethink the role of low voltage networks. With recent advances in smart grid technology, low voltage network automation is emerging as a viable option to traditional network investments. Congestion management and demand response, for example, can be used to keep the network currents and voltages within acceptable limits. In order to control the network, we must first have a comprehensive view on the state of the network. In this paper, the low voltage network monitoring concept proposed by the FP7 European project INTEGRIS is tested. Real-Time Digital Simulator (RTDS) is used to test how well the measurements from secondary substations and smart meters can be combined in a state estimator to get a real-time view of the network state.

Testing the Broadband Power Line communication for the Distribution grid management in a real operational environment

Distribution System Operators are working to improve and extend the level of control of their grid, as response to the new challenges of integrating distribution renewable sources and improving the quality of their service. In doing so, they need also to face up to the problem of reaching their transformer stations via a suitable communication technology, which can guarantee a balanced tradeoff between investments - in terms of cost and time for installation - and benefits - in term of performances (bandwidth, transfer time, reliability and availability). The paper describes real-life experiments carried out by A2A Reti Elettriche SpA - an Italian Distribution System Operator - with the Medium Voltage Broadband Power Line communication (MV-BPL), which is considered one of the most interesting communication technology for Smart Grid applications. Some preliminary results are reported. The paper also describes the hybrid communication - MV-BPL and high rate wireless - defined by the 7th Framework Program European Project INTEGRIS as a way to improve the performance of the MV-BPL.

Experimental characterization of time synchronization over a heterogeneous network for Smart Grids

Nowadays, the growing presence of distributed energy resources (DER) makes the management of the distribution grid more complex, thus requiring distributed monitoring and controlling capabilities. The deployment of locally distributed intelligent devices over a large area involves a high performance network infrastructure (typically based on heterogeneous communication technologies) in order to provide the most appropriate level of communication. In addition, monitoring and control applications need a common sense of time to coordinate the activities among distributed devices, but accurate time synchronization in a heterogeneous network is still a challenge. Network Time Protocol (NTP) can distribute time information with accuracy in the order of milliseconds on a Wide Area Network (WAN). In this work, an experimental characterization of NTP synchronization performance on a real network for Smart Grids has been done. The first analysis highlights the synchronization capabilities span from 1 ms to 20 ms depending on the technology adopted for the deployment of the network (e.g. fiber optics links, BPL links and Wi-Fi).

Smart meters as part of a sensor network for monitoring the low voltage grid

Traditional low voltage grids are equipped with meters for the accounting of the energy consumed by customers. Recently, the use of electronic meters offers the possibility of the remote reading. This paper deals with smart sensing: a second-generation Smart Meters replacing traditional metering device, and the first generation of electronic meters, in order to extract a richer and near real-time information. This information in then transferred on a fast communication network where is needed. In other words, the Smart Meters deployed over the distribution grid create a Sensor Network used for grid control and management. The intelligent unit employed in the proposed system is able to communicate using standard metering protocols like DLMS/COSEM, allowing high-level integration with systems that use this information for both billing and customer relationship management - as is today with Automatic Meter Management systems - and for the technical management of the LV power infrastructure like Distribution Management Systems. The paper presents a pilot installation in a real grid of the smart sensor network composed about 50 new-generation Smart Meters using fast - broad-band - communication. The network of Smart Meters has been used to monitor, during a measurement campaign of two months, the Power Quality of a part of the distribution grid. During the campaign, the grid voltage is below the 5 % of the nominal value only for the 3 % of the time, despite the large presence of distributed renewable resources.

Real-Time Low Voltage Network Monitoring—ICT Architecture and Field Test Experience

Traditionally, distribution network monitoring has been focused on primary substations (i.e., high voltage/medium voltage level), whereas low voltage (LV) network has not been monitored at all. With rapid growth and penetration of distributed energy resources in LV grids, there is growing interest in extending the real-time monitoring to LV level. The framework program FP7 European Project INTEGRIS proposes an integrated real-time LV network monitoring solution and implements it in a cost-efficient way. This solution integrates smart metering data with secondary substation measurements to get a more accurate and real-time view about LV grid, uses “decentralized” distribution management architecture to optimize data flow, and uses International Electrotechnical Commission 61850 Standard-based interfaces to improve interoperability. This paper focuses on information and communications technology perspective, explains the implementation details of this monitoring solution, and presents its functionality/performance testing results from two distribution system operator field trials and from real-time digital simulator laboratory.

SmartDomoGrid: Reference architecture and use case analyses for a grid-customer interaction

The evolution of the electrical energy system toward a smart model has already started. Smart metering, electric vehicles, renewable resources, transmission and distribution advanced grid automation are some example of this ongoing change. A further step in this process is the interaction between final customers - often residential - and the distribution grid. Those customers shall provide new services to the distribution utility which can help them to better and more safely manage the grid. The SmartDomoGrid project - cofounded by the Italian Ministry of Economic Development - is aimed at designing, implementing and testing a possible scheme for the grid-customer interaction in a real operation environment. The paper is focused on the architecture and several use cases proposed and analyzed within the project.

Experimental performance characterization of a meshed network for the Smart Grid

Telecommunication is a prerequisite for the Smart Grid. Several technologies are available on the market, but there is not a general agreement about which of them, or combination of them, that can enable most of the services for the distribution grid automation. The paper describes the approach of 7th Framework Program European Project INTEGRIS which relies on the hypothesis that there is not a single technology with an optimal trade-off between cost of investment and performances for all use cases and topologies of a distribution grid. It rather suggests to mesh several technologies (with focus on the Broadband Power Line, the Wi-Fi and the Fiber Optics) to cover all the segment of the distribution grid. This concept has been experimentally validated in two field demonstrators in Italy and in Spain. This paper presents the results of tests on the latency and the throughput.