Multivariable control design for damping interarea oscillations of bulk power systems using a modal reduction technique

Abstract

A new technique for multivariable control design in order to raise precision and facilitate design procedures is described. The multivariable control scheme for damping improvement of power swings is based on the optimal feedback control theory, and in the design process, eigenvalues of a 2n x 2n matrix for an n-th dimension state equation must be calculated in order to solve the Riccati equation. Hence, in order to apply to a bulk power system, the matrix size must he reduced. By modal reduction technique which is proposed in this paper, the matrix size can be reduced by about 75%. The multivariable control scheme is applied to a 164-machine system. The result shows that the proposed technique enables the multivariable control design for a bulk power system with simple procedures.

Power System Stability

“…An equilibrium point (operating point) of a power system is small-signal stable if it is an asymptotically stable equilibrium point, which is a key goal in the control design of power systems (35,36). From the viewpoint of nonlinear stability analysis, large-disturbance stability such as angle/voltage stability and transient angle/voltage stability belongs to the class of asymptotical stability problems.…”

“…Recently, considerable progress has been made in generating P-V and Q-V curves using an approach based on continuation methods (continuation power flow). Continuation methods, sometimes called curve tracing or path following, are useful tools to generate solution curves for general nonlinear algebraic equations with a varying parameter (36).…”