Power System Monitoring and Control

6Wide-Area Measurement-Based Power System Control Design

Interconnections in a power system are intended to improve the system's reliability and economic efficiency. On the other hand, these interconnections occasionally cause interarea low-frequency oscillation with poor damping characteristics as described in Chapter 2. Therefore, many kinds of methods for designing a damping controller, such as a power system stabilizer (PSS), have been developed to damp interarea oscillations as well as local oscillations [1–3].

Recently, real-time monitoring of power systems based on the wide-area phasor measurement [4] has attracted the attention of power system engineers for the state estimation and system protection especially under a deregulated environment with complex power contracts. A proper grasp of the present state with flexible wide-area control should become a key issue in keeping power system stability properly. As mentioned in Chapter 2, the dynamic characteristics of oscillation modes, especially the interarea low-frequency mode with poor damping, can be detected successfully from phasor measurements [5]. Therefore, detected unstable modes can be damped adaptively and effectively by controlling the power system, for example, by tuning controller parameters based on the measurement data as described in Sections 4.1 and 5.2.

This chapter is mainly focused on the tuning of PSSs using wide-area phasor measurement. The identified low-order model based on the measurement represents ...