Passive Methods to Damp AC Power System Resonance Involving Power Electronics

This paper presents a systematic study of passive methods to damp power system resonances involving power electronics. Passive damping, while requiring additional components and space, overcomes the bandwidth and other limitations of active damping based on control of power electronics. However, existing options for passive damping of ac converter and system impedance are limited and suffer from high power losses. In an effort to develop new damping circuits, this paper examines existing passive damping methods from a different angle and classifies them as first-order and second-order dampers. A systematic approach is then presented to develop new second-order dampers and use them in various configurations to meet the damping requirements of different systems. Two examples are presented to demonstrate the application of the proposed methods. One example is concerned with damping of high-frequency resonance involving MMC-based HVDC converters, and the other is about damping of subsynchronous resonance between type-III wind turbines and series-compensated transmission lines. In both cases, active damping is difficult because of limitations of MMC and type-III turbine control.