Brunel University School of Engineering and Design PhD Theses
Abstract
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 13/09/2010.This thesis describes the implementation of the Flexible AC Transmission Systems
(FACTS) devices to develop a market-based approach to the problem of transmission
congestion management in a Balancing Market. The causes, remedies and pricing
methods of transmission congestion are briefly reviewed.
Balancing Market exists in markets in which most of the trading is done via
decentralized bilateral contracts. In these markets only final adjustments necessary to
ensure secure system operation is carried out at a centralized Balancing Market. Each
market player can participate in the Balancing Market by submitting offers and bids to
increase and decrease its initially submitted active generation output. In this research a
method is proposed to reduce costs associated with congestion re-dispatch in a
Balancing Market by optimal placement of FACTS devices, and in particular Thyristor
Controlled Phase Shifter Transformers (TCPST).
The proposed technique is applicable to both Mixed Integer Linear Programming
(MILP) and Mixed Integer Non-Linear Programming (MINLP). In the MILP a power
system network is represented by a simplified DC power flow under a MILP structure
and the Market participants' offers and bids are also represented by linear models.
Results show that applications of FACTS devices can significantly reduce costs of
congestion re-dispatch. The application of the method based on the MINLP creates a
nonlinear and non-convex AC OPF problem that might be trapped in local sub-optima
solutions. The reliability of the solution that determines the optimal placement of
FACTS devices is an important issue and is carried out by investigation of alternative
solvers. The behavior of the MINLP solvers is presented and finally the best solvers for
this particular optimization problem are introduced.
The application of DC OPF is very common in industry. The accuracy of the DC OPF
results is investigated and a comparison between the DC and AC OPF is presented