This paper discusses the basic design and special applications of wide-area monitoring and control systems, which complement classical protection systems and Supervisory Control and Data Acquisition/Energy Management System applications. Systemwide installed phasor measurement units send their measured data to a central computer, where snapshots of the dynamic system behavior are made available online. This new quality of system information opens up a wide range of new applications to assess and actively maintain system's stability in case of voltage, angle or frequency instability, thermal overload, and oscillations. Recent developed algorithms and their design for these application areas are introduced. With practical examples, the benefits in terms of system security are shown.

In this paper, robust design and tuning of power system stabilizers is considered. A new approach is presented that utilizes recently developed techniques based on linear matrix inequalities (LMIs) for mixed H/sub 2//H/sub /spl infin//-design under pole region constraints. Uncertainty about plant parameters - due to variations in generation and load patterns - is expressed in the form of a linear fractional transformation, and a systematic procedure for constructing the uncertainty representation is proposed. The design is easily carried out by solving a standard LMI problem. Simulation results on a single machine infinite bus model illustrate the method, and the results are compared with a recently proposed approach to the same problem based on quantitative feedback theory (QFT).

This brief presents results on a robust linear quadratic Gaussian (LQG) damping control scheme for improving the inter-area mode oscillations of power systems. A technique is also proposed to guarantee minimum-phase/well-damped transmission zeros by appropriately "squaring" the design plant, for the purposes of efficient robust recovery. A 7th-order multiple-input single-output (MISO) centralized controller is designed for a 16-machine, 5-area power system (138th order) reinforced with a thyristor-controlled series capacitor (TCSC) to improve the damping of the critical inter-area modes by employing appropriate global signal measurements. Loop transfer recovery (LTR) is then applied to reinforce controller robustness in the case of faults and unknown disturbances. The performance of the designed system is assessed in the frequency domain and via appropriate time-domain simulations based upon the nonlinear model under a variety of scenaria

This paper addresses online estimation of electromechanical oscillatory modes in power systems using dynamic data such as currents, voltages and angle differences measured on-line across transmission lines. These measurements are provided by newly installed phasor measurement units (PMUs). Here, the collected data are evaluated with the main objective to detect the dominant frequency and damping of oscillations during normal operation of the power system. The goal is to give the transmission operator qualitative and quantitative information about actual oscillations in the power system as well as about related properties, such as stability margins. The approach is demonstrated on a model of a real power system. Several problems and limitations of the approach are pointed out as well.

An application of a normalized H/sub /spl infin// loop-shaping technique for design and simplification of damping controllers in the liner matrix inequalities (LMI) framework is illustrated in this paper. The solution is sought numerically using LMIs with additional pole-placement constraints. This ensures that the time-domain specifications are met besides robust stabilization. The designed control algorithm is implemented using a rapid prototyping controller. The performance of the controller is validated in real time using a detailed model of the power system implemented using Linux PC-based, multi-processor technology. The coupling between the controller and the power system is through a set of DAC and ADC modules in the analogue domain.

This paper describes an adaptive tuning of parameters of a power oscillation damping (POD) controller for FACTS devices. The FACTS devices considered here are the thyristor controlled series compensator (TCSC) and the unified power flow controller (UPFC). A residue method is applied to the linearized power system model to determine the best siting for FACTS devices as well as for the selection of measured signals. Information available from a higher control level, e.g. from a wide-area monitoring and control platform, is used for a fine tuning of the POD controller in case of changing operating conditions.