Distributed model predictive load frequency control of multi-area
interconnected power system
Miaomiao Ma
a,b,
⇑
, Hong Chen
c
, Xiangjie Liu
a
, Frank Allgöwer
b
a
School of Control and Computer Engineering, North China Electric Power University, No. 2 Beinong Road, Huilongguan, Changping District, Beijing 102206, PR China
b
Institute for Systems Theory and Automatic Control, University of Stuttgart, Pfaffenwaldring 9, 70550 Stuttgart, Germany
c
Department of Control Science and Engineering, Jilin University, Campus NanLing, Renmin Str. 5988, 130025 Changchun, PR China
article info
Article history:
Received 19 May 2013
Received in revised form 18 April 2014
Accepted 22 April 2014
Available online 24 May 2014
Keywords:
Load frequency control
Distributed model predictive control
Generation Rate Constraint
Interconnected power system
abstract
This paper presents a load frequency control (LFC) design using the distributed model predictive control
(DMPC) technique for the multi-area interconnected power system. The dynamics model of multi-area
interconnected power system is introduced, and Generation Rate Constraint (GRC) and load reference set-
point constraint are considered. The overall system is decomposed into several subsystems and each has
its own local area MPC controller. These subsystem-based MPCs exchange their measurements and
predictions by communication and incorporate the information from other controllers into their local
control objective so as to coordinate with each other. Analysis and simulation results for a three-area
interconnected power system show possible improvements on closed-loop performance, computational
burden and robustness, while respecting physical hard constraints.
Ó 2014 Elsevier Ltd. All rights reserved.
Introduction
Power systems are composed of several interconnected subsys-
tems or control areas, and one area is connected to another by the
tie-lines. Each area has its own generator or group of generators,
and it is responsible for its own load and scheduled power
interchanges with neighboring areas. Because of the differences
in generation and load in a power system, systems frequency devi-
ates from its nominal value and active power flow interchanges
between areas deviate from their contracted values. Load frequency
control (LFC) is an important control problem in the dynamical
operation of interconnected power systems. The purpose of the
LFC is to drive the frequency deviation and the inter-area power
flow through tie-lines to zero by manipulating the load reference
setpoint following a disturbance (e.g. a step-change in the system
load). Actually, considering the Generation Rate Constraint and the
load reference setpoint limitation, this task can be theoretically
described as a disturbances attenuation problem of large-scale
systems with state and input constraints.
Recently, there is a growing interest in the LFC problem of
power systems and many different control methods have been
suggested in order to achieve better control performance, based
on various control techniques such as proportional–integral–deriv-
ative (PID) control (e.g. [1–5]), robust control (e.g. [6–12]), fuzzy
control (e.g. [13–17]) and sliding-mode control (e.g. [18–20]).
However, most control methods are implemented in a centralized
manner (e.g. [6,13,15,18] and the reference therein). The controller
has the full knowledge about the overall system and computes all
the control inputs for the system. For any system, centralized
controller can achieve better performance because the effect of
interconnections among subsystems are taken into account
exactly. Furthermore, any conflicts among controller objectives
are resolved optimally. But centralized control is not well suited
for control of large-scale, geographically expansive power systems,
due to the required inherent computational complexity, stability
and robustness, and communication bandwidth limitations [21].
On the other hand, some control methods mentioned above are
based on the decentralized control framework (e.g. [4,22,10] and
the reference therein). The effects of the interconnected subsys-
tems are assumed to be negligible and are ignored in the decentral-
ized control framework. In many situations, however, the previous
assumption is not valid and leads to reduced control performance.
To achieve better closed-loop control performance, some level of
communication may be established between the different control-
lers, which leads to the distributed control of interconnected
power system. In addition, some classical control (e.g. [1–4]) meth-
ods mentioned above could yield unsatisfactory performance since
the effects of nonlinearities such as Generation Rate Constraint and
http://dx.doi.org/10.1016/j.ijepes.2014.04.050
0142-0615/Ó 2014 Elsevier Ltd. All rights reserved.
⇑
Corresponding author at: School of Control and Computer Engineering, North
China Electric Power University, No. 2 Beinong Road, Huilongguan, Changping
District, Beijing 102206, PR China. Tel.: +86 15210122883.
E-mail addresses: mamm@ncepu.edu.cn, ma@ist.uni-stuttgart.de (M. Ma),
chenh@jlu.edu.cn (H. Chen), frank.allgower@ist.uni-stuttgart.de (F. Allgöwer).
Electrical Power and Energy Systems 62 (2014) 289–298
Contents lists available at ScienceDirect
Electrical Power and Energy Systems
journal homepage: www.elsevier.com/locate/ijepes