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This paper presents an integrated approach for designing damping controllers for large power systems. First, a low-order model is identified from a time simulation of the nonlinear power system model. Then an exact multi-modal decomposition is used to develop design indices for selecting an appropriate input signal to the controller. The method is illustrated with the design of thyristor-controlled series compensator damping controllers in two test systems. Keywords - Power system stability, flexible ac transmission systems (FACTS), damping control design, modal decomposition, system identification methods.

Thyristor-controlled series compensation (TCSC) is expected to be applied in transmission systems to achieve a number of benefits. To ensure best use of this new controller, planning engineers require analysis capability tailored to the specific performance characteristics of the TCSC. This paper presents a model for TCSC which is applicable for typical transient and oscillatory stability studies. Also included is a discussion on relevant information to extend the modeling detail of the TCSC for use with long-term stability analysis. Keywords - Flexible AC Transmission Systems (FACTS), Thyristor-Controlled Series Compensation (TCSC), Power System Modeling, Power System Stability, Long-Term Dynamics, Equipment Specification.

The design of controllers sited in the transmission network for damping interarea power oscillations requires several types of analytical tools and field verification methods. Probably the most important aspect of such control design is the selection of proper feedback measurements from the network. This paper describes concepts which provide design engineers with the insight to control performance and the understanding needed to ensure the secure operation of the bulk transmission system. Specific attention is directed to procedures for selecting feedback signals. Keywords - Power system stability, Flexible AC Transmission Systems (FACTS), Control design, Modal decomposition

Thyristor-controlled series compensation systems are expected to provide benefits to utility transmission systems, with applications forthcoming over the next several years. This paper provides basic information on the characteristics and key rating issues associated with these new apparatus, intended to support the anticipated future applications.

Modern dc converter firing control systems utilize phase locked loop techniques to synchronize valve firing-pulses with the ac voltage. Moreover, these systems are becoming digitally based with computers used to control the process. An EPRI research project has provided insight to the behavior of these important control functions. This paper describes a digitally based firing-pulse synchronizing control system, examines some basic dynamic performance issues, and describes a model suitable for small-signal stability analysis of this discrete-time process.

This paper presents a step-by-step analysis of the performance and stability characteristics of a digitally based dc firing-pulse synchronizing control. The performance of the loop is dependent upon parameters of the ac system, dc system, and the primary dc regulators. The synchronizing loop at the inverter tends to destabilize low frequency modes of the overall system. Control loop filtering is an effective means of stabilizing this interaction.