Digitalizing the Electrical Grid: The Smart Rural Grid

By Ramon Gallart

Smart Rural Grid” derives from the more general concept of Smart Grid. A Smart Grid is usually referred to as an energy supply system that is managed by means of advanced information technology, allowing improved control of both, the supply and the demand side of the energy market. This challenge is especially pronounced in rural areas. The technology applied can help to prevent failures and loss of electricity, and to make it easier to find and repair failures when parts of the distribution grid suffer outage. For such a purpose, it is necessary to introduce the quasi-grid concept to explain and apply other ways to create a grid without new electrical infrastructures or network reinforcement investments.

Energy from a disparate set of sources can be routed and rerouted to where it is needed during the flash of a second. In urban areas, the distribution grid usually has several alternative ways to route electricity from the producers to the consumers in private homes, industries, hospitals, and more. If one part of the distribution grid goes down, electricity can be routed another way, so the consumer will not be affected. The Smart Rural Grid project focuses on challenges that are specific for rural areas with few alternative distribution routes for electricity.

Estabanell Energia has more than 50 percent of his network in rural areas. In 2013 we noticed that there was a growth of the distributed generation in such places, while the shape-tree topography of the rural networks was not suitable for creating a true Smart Grid. For solving this issue, avoiding the traditional solution of creating new networks, we focused on power electronics solutions, for which we needed specific partners. After the creation of a pan-European consortium, the project was presented to the FP7 funding of the European Commission. The total cost of the project is 4.944.690€, of which 3.239.539€ have been funded by the EC. This is a three-year project, ending in June 2017.

Therefore, smart rural distribution grids have to be designed, planned, maintained and – if necessary - repaired in different ways than smart urban distribution grids.

Smart Rural Grid project goals

• To develop an Intelligent distribution power router (IDPR).
• To develop and improve new power line communications (PLC) technology for rural distribution network and apply a robust communication network that allows managing distributed energy resources (DERs) and IDPRs.
• To create a data and energy control system that manages local micro-production and IDPR units. These systems are based on bidirectional powers and information flows re-dispatching power generation to optimize the whole.
• Integration of new smart grid technologies. It consists of establishing the defined protocols for the real-time communications between new devices (IDPR, RTU and Industrial PC).
• An energy storage system (ESS) that enables new operation modes and increases continuity of supply.

Therefore, the Smart Rural Grid project emerges as a response to such necessities. The SRG project will explore and in turn show how to exploit the convergence between electricity and telecom networks. The work undertaken aims to show how utilities can operate more efficiently and to interconnect energy prosumers to enable a multi-directional flow of energy. The SRG Project explores the best way to make the transition from the current rural distribution network to the new using the Smart Grid technologies and associated business concepts.

The solution to digitalize the electrical rural grid, is based to segment the grid into substantially self-sustaining cells, then control the flow of energy between those cells using controlled, scheduled energy flows thanks to an intelligent distribution power router (IDPR) that is a four-wire parallel active filter that is enhanced with distributed intelligence. The aim is to optimize the use of distributed resources in any operation mode allowing to route the energy according to the needs of unbalanced grids and to improve quality of service (in terms of continuity of supply and quality of waveforms).

This segmentation can be done gradually in the Low Voltage network, the Medium Voltage one, or in both. Any failure on the SRG can give self-healing capabilities to start to work in a dynamic island mode because the electrical border are depending constrains identified using the electrical management system. The independent cells or systems located in each secondary substation, with mutually synchronized phases and frequencies are connected using the IDPR composed of power converters which exchange electric energy between selected parts of network by supplying specified energy directly through power converters to the designated endpoint defined by an address.

In each secondary substation there are power equipment control devices called local controllers (LC) and transformers controllers (TC) that are used to transfer information and thereby control power equipment such as generators and energy storage devices. They are assisted by a local energy management system (LEMS) that has data transactions among energy management systems to forecast and give essential support for operational decision-making. During the late fall, the file format for data transaction between servers and SCADA was validated and the work has been completed.

Therefore, we believe that the outcomes of the project will facilitate the growth of the distributed generation in non-urban areas, based on a disruptive change in the management of the LV networks.

For a downloadable copy of  November 2016 eNewsletter which includes this article, please visit the IEEE Smart Grid Resource Center.

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