Abstract:
Energy shortage is considered as the most critical infrastructure constraint to the economic
growth of Bangladesh. One of the main causes of the supply shortage, among others, is the
poor operational efficiency of power plants. For the operation of a large power system
maintaining the proper power quality has always been a difficult task. Increasing number of
major power grid blackouts that have been experienced around the world including
Bangladesh (2007, November and December) in recent years show that today’s power
system operation requires more careful consideration of all forms of system instability and
control problems and introduction of more effective and robust control strategies. In this
thesis an Active disturbance rejection control (ADRC) based decentralized Load Frequency
Control (LFC) system for Bangladesh Power System (BPS) is developed and a proposal has
been made for feedback connections from various load rich areas to generation rich areas to
minimize the area control error. The frequency control system maintains frequency and tieline
power flows to specified values in the presence of physical constraints and model
uncertainties. As power load demand varies randomly in an interconnected power system,
both area frequency and tie-line power interchange also vary. The objectives of LFC are
to minimize the transient deviations in these variables (area frequency and tie-line power
interchange) and to ensure their steady state errors to be zeros. Unexpected external
disturbances, parameter uncertainties and model uncertainties are big challenges for
LFC design. As an increasingly popular practical control technique, ADRC has the
advantages of requiring little information from the plant model and being robust against
disturbances and uncertainties. A solution to the LFC problem based on ADRC is an
alternative one. Performance analysis of ADRC is done by comparing with Proportional
Integral Derivative (PID) controller and for two area non-reheat and reheat turbine unit.
ADRC is also implemented on a large power station. Finally, the design of BPS is done
considering its radial connection and proposal is made about feedback connection based on
the performance of ADRC. The dynamic model of the power system and the controller
design based on the model are elaborated. Simulation results show that ADRC controller is
attractive for the LFC problem in terms of its stability and robustness.
