Wide-area damping controller of FACTS devices for inter-area oscillations considering communication time delays

Abstract

The usage of remote signal obtained from a widearea measurement system (WAMS) introduces time delays to a wide-area damping controller (WADC), which would degrade system damping and even cause system instability. The time delay margin is defined as the maximum time delay under which a closed-loop system can retain stable. In this paper, the delay margin is introduced as an additional performance index for the synthesis of classicalWADCs for flexible AC transmission systems (FACTS) devices to damp inter-area oscillations. The proposed approach includes three parts: a geometric measure approach for selecting feedback remote signals, a residue method for designing phase compensation parameters, and a Lyapunov stability criterion and linear matrix inequalities (LMI) for calculating the delay margin and determining the gain of the WADC based on a tradeoff between damping performance and delay margin. Three case studies are undertaken based on a four-machine two-area power system for demonstrating the design principle of the proposed approach, a New England 10-machine 39-bus power system and a 16-machine 68-bus power system for verifying the feasibility on larger and more complex power systems. The simulation results verify the effectiveness of the proposed approach on providing a balance between the delay margin and the damping performance.

Nonlinear Synergetic Governor Controllers for Steam Turbine Generators to Enhance Power System Stability

“…In this subsection, the New England system [40][41][42][43][44] shown in Figure 8 is applied to demonstrate the effectiveness of the NSGC in a multi-machine power system. All the loads are considered as the constant impedance model.…”

An Improved Multi-Infeed Effective Short-Circuit Ratio for AC/DC Power Systems with Massive Shunt Capacitors Installed

“…Based on the New England 39-bus system modified in [27,28] and the initiative of designing cases near the stability boundary, here we replace the generators on bus 33 and 35 with two DC inverter stations, the active power injected by the DC transmission line is the same as that generated by the generators being replaced, and the capacity of the capacitors installed at the inverter buses is half of the active power injected by the DC transmission. After the modification, the system becomes a 2-DC infeed system, and the modified New England system is illustrated in Figure 4.…”

Selection of feedback signals for controlling dynamics in future power transmission networks

“…However, in practical scenario, each signal will be associated with its own time delay. Various controller design methodologies proposed in [27]- [29] could be used to tackle the problem caused by the time delay uncertainties. Since the objective of this paper is to demonstrate signal selection methodology, the simple residue-based controller design method is used in this paper.…”