PhD programme
by Tilman G. Weckesser
Student no s090952
Period
September 2011 to August 2014
Main-Supervisor
Co-Supervisor
Hjörtur Jóhannsson, EES/CET, DTU Electrical Enginering
Description
A series of blackouts, taken place in 2003, exposed the dependency of today’s society on a secure and stable electric power system. Furthermore, the blackouts gave impetus to establish research groups analyzing the events leading to the collapse of the electric power systems. The findings of these studies were the need for improving security of supply. The privatization of the power grid in several countries and thereby the exposure to certain market forces led to the loss of the former state of reliability, which was an inherent result of structural redundancy.
At the same time the dependency on a secure and stable power supply is further growing, due to e.g. the imminent introduction of electrical vehicles. Another factor that can lead to a weakening of the power system stability may be the growing fraction of electric energy generated from renewable energies, where the energy sources are mainly non-controllable and the production is depending on forecast accuracies. The growing dependency and the increase of power generation relying on forecasts may lead to more stringent requirements for the stability assessment.
However, the state-of-the-art computer tools, which are used to analyze the power system stability conditions, utilize computational intensive approaches and therefore are conducted off-line. In a power system with a high share of energy produced by means of uncontrollable renewable energy sources this time consuming approach is no longer sufficient to ensure a stable and secure system operation. Hence, there is a need for developing assessment methods, which allow a fast evaluation of the power system stability and security.
The ongoing installation of wide area measurement systems is improving the possibilities to monitor as well as to analyze the state of the power system. Recent research at the Center for Electric Technology has focused on the evaluation of the current steady-state stability condition of the power system.
This project aims at the development of an algorithm to dynamically evaluate the stability of the power system in case of facing a severe perturbation, e.g. a loss of a generation or a transmission unit. The method will analyze the ability of the power system to survive the transient system response as well as the capability to establish a new stable operating point. This analysis requires determining of the response of each single generator as well as the interaction between the neighbouring generators. In order to allow a fast screening of the power system, it has to be investigated amongst other things, which assumptions can be made to simplify the evaluation problem.
2012 February TGW |