Using Demand Response to Shape the Fast Dynamics of the Bulk Power Network

Demand-side strategies for shaping the fast dynamics of the bulk power transmission network are explored. Specifically, the design of demand response strategies is pursued, with the aim of modulating the network’s operating point so as to achieve desirable small-signal characteristics. The design problem is posed as an optimization problem wherein the total demand responsive load is held constant but shifted between different buses, to maximize a performance metric which captures disturbance susceptibility and control-channel performance. The problem is solved numerically with an iterative linear programming algorithm that uses eigenvalue sensitivity analysis and linearizations of the nonlinear constraints. Formal characterization of the optimal solution is also explored. A small-scale case study using the Kundur 11-bus two-area test system demonstrates that, by shifting the load between two areas, the smallest damping ratio of the generator modes (corresponding to the disturbance susceptibilty) and the smallest damping ratio of the finite zeros of the input-output transfer function (corresponding to the control channel performance) can be improved. The improvements due to load shifting are compared to those possible with generator re-dispatch and voltage regulation.