An Architecture for FACTS Controllers to Deal With Bandwidth-Constrained Communication

Abstract

Abstract-Bandwidth constraints could have adverse impact on the flexible AC transmission system (FACTS) controllers relying on signals communicated from distant locations. An observer driven system copy (OSC) architecture is adopted here to deal with low data rates caused by the limited bandwidth availability. The basic idea is to use the knowledge of the nominal system to approximate its actual behavior during the intervals when data from the remote phasor measurement units (PMUs) is not available. This is corrected whenever the most recent states are obtained from the reduced order observer at the PMU location. The closed-loop behavior deteriorates as the operating condition drifts away from the nominal. Nonetheless, significantly better response is achieved under limited bandwidth availability as compared to the conventional approach of communicating the measured outputs. The deterioration is quantified in terms of the difference between the nominal and the off-nominal condition. (e-mail: n.chaudhuri@imperial.ac.uk, b.chaudhuri@imperial.ac.uk Index Terms-

Stability analysis of networked control in smart grids

“…A steady state solution for in (13), and hence for , may or may not exist for given and , even if the conditions for the existence of steady state solution for a standard Kalman filter hold; but a steady state estimate for the Kalman gain may be obtained by iteratively solving (11), (13) and (14) after substituting with its expected value . This is the suboptimal Kalman gain which is used for deriving the condition for mean square stability and adequate damping of the developed NCSG.…”

“…In most of the literatures relating to power systems, it is assumed that the transmission of signals to and from the central control unit occurs over an ideal, lossless and delay-free communication network. A few exceptions to this are [11], [12] and [13]. In [11] the effect of network induced time-delays has been considered using a WAMS based state-feedback control methodology.…”

“…In [11] the effect of network induced time-delays has been considered using a WAMS based state-feedback control methodology. In [12] an estimation of distribution algorithm (EDA) based speed control of networked DC motor system has been studied; and in [13] the effect of communication-bandwidth constraints on the stability of This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see http://creativecommons.org/licenses/by/3.0/ WAMS based power system control has been studied.…”

“…In [12] only a local network based control of a single dc-motor system is considered instead of considering the networked control of a complete power-system. In [13], the chief problems associated with networked-control, which are packet-loss and delay, are not considered. This paper has made an attempt to address the aforementioned limitations by analyzing the effects of packet-dropout on the oscillatory stability response of a networked controlled smart grid (NCSG).…”

Fault-tolerant wide-area control for power oscillation damping

“…Another potential problem could be low data rate/bandwidth availability which is likely to be encountered Support for networked communication if WAMS infrastructure were to be shared between multiple data intensive services in future. A solution to this problem was presented in [5]. Despite a number of papers on latency and less so on the bandwidth problem, very little has been reported on tackling the situation where one or more remote signals are completely lost.…”