An extended linear quadratic regulator for LTI systems with exogenous inputs

This paper proposes a cost effective control law for a linear time invariant (LTI) system having an extra set of exogenous inputs (or external disturbances) besides the traditional set of control inputs. No assumption is made with regard to a priori knowledge of the modeling equations for the exogenous inputs. The problem of optimal control for such a system is defined in the standard framework of linear quadratic control and an extended linear quadratic regulator (ELQR) is proposed as the solution to the problem. The ELQR approach is demonstrated through an example and is shown to be significantly more cost effective than currently available approaches for linear quadratic control

Decentralized nonlinear control for power systems using normal forms and detailed models

This paper proposes a decentralized method for nonlinear control of oscillatory dynamics in power systems. The method is applicable for ensuring both transient stability as well as small-signal stability. The method uses an optimal control law which has been derived in the general framework of nonlinear control using normal forms. The model used to derive the control law is the detailed subtransient model of synchronous machines as recommended by IEEE. Minimal approximations have been made in either the derivation or the application of the control law. The developed method also requires the application of dynamic state estimation technique. As the employed control and estimation schemes only need local measurements, the method remains completely decentralized. The method has been demonstrated as an effective tool to prevent blackouts by simulating a major disturbance in a benchmark power system model and its subsequent control using the proposed method

An extended linear quadratic regulator and its application for control of power system dynamics

This paper presents a generalized solution to the problem of optimal control of systems having an extra set of exogenous inputs besides control inputs. The solution is derived in the framework of linear quadratic control and it is termedextended linear quadratic regulator (ELQR)'. The ELQR is applied for control of unstable or poorly damped oscillatory dynamics occurring in a power system and is shown to be significantly more cost effective than the classical power system stabilizer (PSS) based approach

Report on the 68-bus, 16-machine, 5-area system

The present report refers to a small-signal stability study carried over the 68-Bus, 16-Machine, 5-Area System and validated on a widely known software package: MATLAB-Simulink (ver. 2012b). The 68-bus system is a reduced order equivalent of the inter-connected New England test system (NETS) and New York power system (NYPS), with five geographical regions out of which NETS and NYPS are represented by a group of generators whereas, the power import from each of the three other neighboring areas are approximated by equivalent generator models. This report has the objective to show how the simulation of this system must be done using MATLAB in order to get results that are comparable (and exhibit a good match with respect to the electromechanical modes) with the ones obtained using other commercial software packages and presented on the PES Task Force website on Benchmark Systems for Stability Controls

Decentralized robust dynamic state estimation in power systems using instrument transformers

This paper proposes a decentralized method for estimation of dynamic states of a power system. The method remains robust to time-synchronization errors and high noise-levels in measurements. Robustness of the method has been achieved by incorporating internal angle in the dynamic model used for estimation and by decoupling the estimation process into two stages with continuous updation of measurement-noise variances. Additionally, the proposed estimation method does not need measurements obtained from phasor measurement units (PMUs); instead, it just requires analogue measurements of voltages and currents directly acquired from instrument transformers. This is achieved through statistical signal processing of analogue voltages and currents to obtain their magnitudes and frequencies, followed by application of unscented Kalman filtering for nonlinear estimation. The robustness and feasibility of the method have been demonstrated on a benchmark power system model

Nonfactorizable Contribution to B-Meson Decays to s-Wave Mesons

Two-body weak decays of bottom mesons into two pseudoscalar and pseudoscalar and vector mesons, are examined under isospin analysis to study nonfactorizable contribution