23 rd International Conference on Electricity Distribution Lyon, 15-18 June 2015 Paper 0246 CIRED 2015 1/5 INNOVATIVE SOLUTION OF SAFETY CORRIDOR DESIGN FOR OVERHEAD LINES: INCREASING RESILIENCE TO EXTREME WEATHER EVENTS WHILE PROVIDING ENVIRONMENTAL BENEFITS Ricardo PRATA Silvestre PEREIRA Miguel VIEIRA Maria Inês VERDELHO Portugal Portugal Portugal Portugal ricardo.prata@edp.pt silvestre.pereira@edp.pt miguel.vieira@florasul.pt mariaines.verdelho@edp.pt ABSTRACT This paper proposes the concept of the Risk Management Buffer, consisting in the extension of the existing safety corridors in HV/MV lines. We present the pilot project in Louriçal, which is being implemented with this concept. This approach aims at increasing line resiliency, based on a risk assessment for MV and HV overhead lines, due to falling or contact of trees located outside the safety corridors, particularly when associated with Extreme Weather Events, while providing environmental benefits. The methodology associated with the creation of the Risk Management Buffer concept was developed with the involvement of an environmental agency. The deployment of that methodology in the areas where a positive cost- benefit analysis is achieved must involve the landowners on the intervention areas, thus being conceived in order to guarantee benefits for all of the stakeholders. INTRODUCTION Portugal has a very large proportion of its territory covered by forests – 3.2 million hectares, 35 % of the territory. EDP – Distribuição (EDPD), the Portuguese DSO, operates MV and HV overhead lines that are established within forests (8,300 km included in protected areas for nature conservation) and, therefore, exposed to hazards like wildfires and damages caused by tree falling, particularly under extreme weather events. Portuguese legislation obligates the DSO to establish and manage overhead line safety corridors, including forest fuel management (Decree No.124/2006 [1]). Nevertheless, those safety corridors have revealed to provide an inadequate protection during extreme weather events (EWE). Trees, as high as 40 m, located outside the safety corridor, might fall under those conditions. Portugal has also experienced several EWE recently, which had a negative impact on the reliability of the distribution network. Figure 1 shows daily interruption time (in minutes), highlighting the impact of four storms that occurred since 2009 [2]. Figure 1 Daily interruption minutes EDPD developed two separated research efforts, aiming not only at increasing the resilience of overhead lines established within forests, but also managing safety corridors with solutions that yield positive environmental impacts. The concept of a Risk Management Buffer (RMB) was developed. EWE might originate tree falling or agitation, leading to contacts with branches. These events are more likely to occur in areas with strong wind turbulence, high trees (particularly isolated pine trees or eucalyptus), pine trees weakened by a parasite (nematode), or isolated trees on instable soils. On those areas, RMB must be wider, being defined by the location and size of trees that might fall off over the line. RMB is identified through the use of helicopter-mounted LiDAR surveys. Through a study of the Portuguese Institute of the Sea and the Atmosphere (Instituto Português do Mar e da Atmosfera – IPMA) with University of Lisbon (ULisboa) on the meteorological impact on the electrical infrastructure of continental Portugal [2], we are implementing a pilot project in Louriçal which is a vulnerable region to EWE (combining high wind exposure with the existence of extensive forest covers, and instable soils) using the RMB concept. RMB is expected to increase resiliency of overhead lines to extreme meteorological events. The results of this pilot project will be evaluated and, if proved worthy, this approach will be used in other areas identified as vulnerable. METHODOLOGIES Given the goal of this project, to increase overhead line resilience, we introduce the Risk Management Buffer concept, RMB. Adverse weather conditions is the main cause of contacts with branches, due to tree falling or agitation. Exposure to this phenomena of natural origin can be estimated by consulting the following cartographies:  Territorial conditions;  Land use conditions (forest cover);  Other potential aggravating conditions. The territorial conditions' cartography includes the average map of turbulence of winds exciding 30%, the soil map of structural instability and the orographic map. The Land Use Cartography (LUC) includes forest species in the neighbouring of overhead lines, and the pine trees potentially affected by pests and diseases. Other potential aggravating conditions are described in