PhD Thesis Final Defense to be held on June 12, 2019, at 11:00

Photo credit: Nikolaos Koutsoukis

The examination is open to anyone who wishes to attend (Multimedia Room, Central Library of NTUA).

Thesis Title: Optimization of operation and planning of active distribution networks

Abstract: This PhD thesis focuses on the development of innovative methods for the optimal operation of active distribution networks (ADNs) under normal and emergency conditions, and for the optimal long-term planning of ADNs. A novel distribution network reconfiguration method is developed for the optimal operation of ADNs in normal conditions, i.e., when all network components are available. The method deals with the main technical problems arising in distribution networks (DNs) due to high penetration of renewable energy sources (RES), such as voltage rise and line congestion, without curtailing the active power output of distributed generation (DG) units. The proposed method is based on a mixed integer second order cone programming (MISOCP) optimization model and it is employed for the day-ahead scheduling of the ADN by defining the optimal network configuration, based on load and renewable generation forecast. For the operation of the network in emergency conditions, i.e, when a permanent fault occurs, a novel method for the optimal service restoration of ADNs with high penetration of RES is developed. The method is based on a MISOCP optimization model and aims at minimizing the out-of-service areas and the number of switch operations. The proposed service restoration method considers the capabilities of the active network management (ANM) by enabling the control of the reactive power output of the DG and highlights the importance of incorporating ANM into the solution of the service restoration problem. Moreover, for the efficient solution of the problem, the network’s operating constraints are relaxed and the operation of the network’s voltage regulation devices is considered.

Furthermore, a novel multi-stage method for the long-term planning of ADNs is developed. The proposed method considers multiple planning alternatives, such as substation reinforcement, line reinforcement, installation of new lines, capacitor and voltage regulator placement, while it exploits the control capabilities of ADNs in order to minimize the investment costs of distribution network planning (DNP). The DNP problem is divided in two subproblems in order to reduce its complexity. The solution of the first subproblem computes the type, the location and the capacity of the planning alternatives, which ensure the safe operation of the network during the whole planning period. The solution of the second subproblem calculates the installation time of the calculated planning alternatives.

Supervisor: Pavlos Georgilakis, Associate Professor

PhD student: Nikolaos Koutsoukis