Optimization of capacitor banks in the Skagerak networks transmission grid

Masteroppgave i fornybar energi ENE500 2013 – Universitetet i Agder, GrimstadCapacitor banks have been widely used in electric power networks. This master thesis presents a study of introducing new capacitor banks into a transmission network. The network comprises two areas at Telemark and Vestfold with voltages levels of 55kV, 66kV and 132kV, owned by Skagerak Nett AS. Capacitor banks improve the electric network in five ways: power factor correction, increased capacity, reduction of losses, voltage support and reactive power support. International standards and regulations regarding capacitor banks usage, as well as technological related considerations, have been explained. Network improvements are always required. The main goal of this project is to find an optimum solution for the installation of new capacitor banks in the Skagerak Nett network. The optimal solution is the one that minimizes cost of operation of the grid and investment in capacitor banks. The project aims to find the optimum solution for the whole network and the analysis includes the economic viability of the solution. The optimum capacitor placement problem consists of determining sizes and location of capacitor banks in order to optimize an objective function. The problem is solved using various genetic algorithms. Genetic algorithms are implemented with Python, which can use the capabilities of PSS/E, where the network data is stored. The objective function includes data from high load season, investment costs, power losses, reactive power losses and maintenance. The constraints of the problem limit the voltage, power factor and capacitor bank power. Economic aspects are also part of the objective function. The results show that the electric power networks under consideration can be improved with the introduction of capacitor banks and that costs are reduced. The investments in the capacitor bank solutions are recommended as they offer savings respect the no investment option. The proposed capacitor bank configurations consists of 14 and 13 capacitor banks in Telemark and Vestfold, distributed in 7 and 10 transformer stations respectively, with power ratings that range from 6 to 20 Mvar. The savings of both proposals have been estimated to 68 and 40 MNOK during the investment period