Power-Imbalance Allocation Control of Power Systems-Secondary Frequency Control

• Main Authors: Xi, Kaihua, Dubbeldam, Johan L. A, Lin, Hai Xiang, van Schuppen, Jan H
• Format: Journal Article
• Language: English
• Published: 15-07-2018
• Subjects: Mathematics - Optimization and Control
• DOI: 10.48550/arxiv.1703.02855

The traditional secondary frequency control of power systems restores nominal
frequency by steering Area Control Errors (ACEs) to zero. Existing methods are
a form of integral control with the characteristic that large control gain
coefficients introduce an overshoot and small ones result in a slow convergence
to a steady state. In order to deal with the large frequency deviation problem,
which is the main concern of the power system integrated with a large number of
renewable energy, a faster convergence is critical. In this paper, we propose a
secondary frequency control method named Power-Imbalance Allocation Control
(PIAC) to restore the nominal frequency with a minimized control cost,in which
a coordinator estimates the power imbalance and dispatches the control inputs
to the controllers after solving an economic power dispatch problem. The power
imbalance estimation converges exponentially in PIAC, both overshoots and large
frequency deviations are avoided. In addition, when PIAC is implemented in a
multi-area controlled network, the controllers of an area are independent of
the disturbance of the neighbor areas, which allows an asynchronous control in
the multi-area network. A Lyapunov stability analysis shows that PIAC is
locally asymptotically stable and simulation results illustrates that it
effectively eliminates the drawback of the traditional integral control based
methods.