Energy distribution: networks and smart grids

Distribution networks     

Acea Distribuzione is the Group company which holds the Ministerial concession for the management of the electricity distribution network serving Rome and Formello, covering around 29,000 km and capable of serving roughly 2.7 million resident inhabitants.

In terms of volumes of electricity distributed, around 12,000 GWh per year, Acea is the third leading Italian operator in the sector. Table No. 81 shows the main plant figures.

Table No.81 – Overhead and underground distribution lines and plants: numbers (2010-2012)

Type Unit of measurement 2010 2011 2012
Plants and outputs
HV/HV - HV/MV primary sub-stations No. 68 68 69
HV/HV and HV/MV transformers No. 173 174 173
Power transformation MVA 7,623 7,693 7,750
Secondary sub-stations running No. 12,982 12,979 13,030
MV/MV - MV/LV transformers No. 12,567 12,671 12,749
Transformation capacity MVA 5,750 5,845 5,953
Overhead and underground networks
High voltage networks - overhead lines Km 372 372 372
High voltage networks - underground lines Km 241 241 241
Medium voltage networks - overhead lines Km 494 488 475
Medium voltage networks - underground lines Km 9,526 9,705 9,775
Low voltage networks - overhead lines Km 1,697 1,689 1,683
Low voltage networks - underground lines Km 16,997 17,148 17,324

Energy losses on the network, due mainly to the heating of the conductors as a result of the Joules effect, come to around 6.4% of total energy conveyed, in line with the average values in Italy (see the Environmental accounts for greater details).

The preparatory activities for the launch of work concerning reorganisation of the high (150 kV) and very high (220 and 380 kV) voltage distribution and transmission network continued in 2012, according to the Memorandum of Intent signed by Acea Distribuzione, Rome City Council and Terna SpA. The project envisages the construction of 123 km of new overhead lines and the demolition of nearly 300 km of overhead lines existing in an area which passes through a good 11 protected natural areas. The objective is to obtain the prescribed authorisations in 2013 and plan the launch of the work for the following year.

Smart grids  

Acea Distribuzione presented the AEEG with a smart grid project in November 2010, which was chosen and included among the pilot projects receiving incentives98. The application of the innovative technology concerns a network already running in the Malagrotta - Ponte Galeria area and represents the first step in a more extensive network modernisation plan. The pilot project was launched in January 2011; work continued during 2012 and will be completed during the first half of 2013, a little later than expected. The related box illustrates the stage of completion and the work carried out during the year for each of the six main sections.

Another project devised by Acea Distribuzione for the purpose of improving the performances of the networks thanks to the evolution and integration of the operating systems dedicated to their management is the Smart-network Management System. Thanks to the innovative contents it features, the project was presented in 2010 to the Ministry for economic development with application to access the financial subsidies envisaged by the fund for technological innovation (FIT); following the positive conclusion of the contractual stage, in July 2012 the company presented the final project (see box for further details).

98 See Resolution ARG/elt 12/11.

Box - Acea Distribuzione’s Smart grid pilot project: stage of completion in 2012

Acea Distribuzione’s Smart grid project is divided up into the following six main sections:

  1. MV network automation(evolved automatic selection of section fault; handling of the distributed generators - remote tripping and calibration change) – the installation of the field apparatus was completed and the evolved automation was brought into service on a distributor without distributed generation. During the second half of 2012, tests were carried out in the testing field (care of CP Flaminia) and the installations in the field necessary for the running of the evolved automation on the distributors with distributed generation.
    The stage of completion at the end of 2012 was 95%. The field tests for the distributors with distributed generation will be completed by March 2013.
  2. monitoring of the MV and LV network –the monitoring chapter in 2012 achieved completion with the installation, test & inspection and bringing onto stream of all the apparatus necessary for the acquisition of the electrical and environmental magnitudes relating to the MV and BV networks. The stage of completion at year end was 100%.
  3. new criteria for managing the MV network (load flow management; optimisation of the voltage profiles; minimisation of the losses) – during 2012, the “RSE Vocant” optimiser model was implemented in the remote-control system; the tests carried out in the field had a positive outcome. Collaboration with La Sapienza University in Rome made it possible to define, develop and validate a genetic algorithm for the topological optimisation of the network which takes into account the minimisation of the losses, the load forecasts and the supply on the network. The stage of completion at the end of 2012 was 85%. During the first half of 2013, the field tests will be completed;
  4. e-car & storage (smart storage; MV network management and control system with interface for photovoltaic plant, electric vehicle and thyristor voltage regulator equipment -TVR) – during the year, the first phase of the project was completed with the installation of the storage system co-ordinated with a photovoltaic plant and with recharging stations. During 2012, analysis was carried out on the functioning of the complex and the test & inspection was carried out on the connection of the stations installed with a control center (known as Office Center) so as to experiment the remote management of the same. The installation of the TVR device is envisaged during 2013 with the related interface towards Acea Distribuzione’s Electric Operations Centre for the regulation of the voltage on the MT distributor on which installation is envisaged. The stage of completion at year end was 100%.
  5. primary station diagnostics – with regard to the CP diagnostics, the aspects envisaged both with regard to the field and centre were completely installed; the testing and streamlining stage for the system concluded in the first few months of 2012.  The stage of completion at year end was 100%.
  6. identification of the trigger point for transitory faults - the field installation phase has concluded and the installation at the centre (CEDET) of a monitoring and control station for the entire system has been completed. The monitoring stage ended in the second half of 2012. The stage of completion at the end of 2012 was 100%.

Box - The technological innovation project “Smart-network Management System”

The Smart-network Management System (SMS): technological evolution in the management of the electricity distribution network project essentially came about due to the need to integrate and evolve the operating system for the management of the electricity networks for the purpose of improving the performances of said networks, in accordance with the quality objectives established by sector legislation. In fact, it is well known that over the space of the last decade the AEEG has issued numerous resolutions which, overall, define important improvements to be achieved with regard to the quality and efficiency of the electricity distribution service.

As a result of its innovative contents, the project falls within the regulations established at national level for the support of technological innovation and, therefore, in June 2010, Acea Distribuzione presented the Ministry for economic development with an application for access to the financial subsidies availing of the fund for technological innovation (FIT), as per the envisaged procedures. The project, which has duration of three years and is divided up into several sub-projects aimed at making the most of and developing the initiatives already established by the company for improving the continuity of the electricity service and increasing the operating efficiency, was - with regard to the preliminary and layout phases - effectively launched in July 2010. At the end of 2010, the Ministry formalised the go-ahead as per the procedures envisaged Italian Ministerial Decree dated 14 December 2009. This procedure has continued since then: during 2011, operating activities were launched for the sub-projects along with their systematic monitoring and, at year end, the contractual phase with the Ministry was launched. Further to a specific focus meeting with the scientific committee of the Ministry, Acea Distribuzione presented a report aimed at specifying the contents and the innovative nature of the initiative, as well as the assimilation of certain guidelines. The negotiation stage had a positive outcome and in July 2012 Acea Distribuzione was able to present the final project proposal, for a total amount of around Euro 11.6 million. In December 2012, the first appraisal visit was made by the Ministerial representatives, carried out with the aim for Acea Distribuzione of providing a response to a number of requests for further information by January 2013.