Integrating wind generation in the distribution network

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Energias Renováveis – Conversão Eléctrica e Utilização Sustentáveis

One of the current challenges the electricity grid has is to actively connect future generation to its network without the need to fully reinforce it. This dissertation will study the use of dynamic ratings on overhead lines to increase its capacity and thus defer major investment on infrastructure reinforcement. The amount of current an overhead line can withstand in a given time is defined by the distance towards the ground, which is proportional to the conductor´s temperature, which is given by a static rating stated in the P27 standard – “Current Rating Guide for High Voltage Overhead Lines Operating in the UK Distribution System”. This rating changes from season to season and depends on specific values for ambient temperature, wind speed, wind direction and the probability that in a year the conductor exceeds its design temperature. This standard is seen as being very restrictive and a limiting factor on overhead line capacity for both future generation connections and demand. Wind speed and direction are extremely important on the cooling of overhead lines and in times of strong winds the conductor cools down, allowing extra amount of current to flow through it. By using real time weather data, it´s possible to obtain the maximum current that can flow in an overhead line for a specific operating temperature and assess the amount of headroom possible given by the difference between the static ratings and the new dynamic ratings is assessed. A view on the extra amount of energy produced, as well as CO2 emission savings and profit will also be presented, giving a practical result by applying dynamic ratings.