Power Transfer Control Research Articles

An online preventive control approach for dynamic security of power transmission using a database system

This paper presents the development and application of a novel relational database named dynamic security assessment (DSA) database system for online dynamic security preventive control of power transmission in interconnected power systems. The structure, organization, management and functions of the DSA database system are introduced in the first part of this paper. Mathematical model and algorithm with an application of the DSA database for minimum cost preventive security control of power transfer are then presented. Case studies of the online control algorithm on the 10-generator New England test system are reported to show the effectiveness of the approach. In particular, the process of rescheduling of generations in order to guarantee an optimal security operation of systems is demonstrated.

Part-load and dynamic performance of a medium-speed four-stroke engine with two-stage turbo charging and power transfer system

The development of big diesel engines in the past resulted in continuously rising mean effective pressures. If this trend persist two-stage turbocharging will be necessary in the future. In the past, two-stage turbocharging resulted in poor part load performance. As a solution of this problem a system with controlled power transfer between the crankshaft and the low-pressure turbocharger is proposed. To simulate such a system a computer programme was made. It was used to study the behaviour at part-load and load increase for propeller operation. The two-stage turbo charging system with power transfer is suitable for big diesel engines with considerably higher mean effective pressures.

Control Design of STATCOM With Superconductive Magnetic Energy Storage

This paper describes the control design of a SMES power conditioning system for static reactive power compensation at distribution voltage levels. This system comprises a five-level voltage source inverter and a five-level two-quadrant chopper fed from SMES. Due to the high order nonlinear nature of multilevel converters, a multivariable control method is proposed to enable high-bandwidth control of power transfer to and from the SMES coil. Theoretical analysis of the controller design and the simulation results are presented.

Observation of Critical Coupling in a Fiber Taper to a Silica-Microsphere Whispering-Gallery Mode System

We present the observation of critical coupling in a high- Q fused-silica microsphere whispering-gallery mode resonator coupled to a fiber taper. Extremely efficient and controlled power transfer to high- Q ( approximately 10(7)) resonators has been demonstrated. Off-resonance scattering loss was measured to be less than 0.3%. On-resonance extinction in transmitted optical power through the fiber coupler was measured as high as 26 dB at the critical coupling point. This result opens up a range of new applications in fields as diverse as near-field sensing and quantum optics.

Controlled power transfer from wind driven reluctance generator

The paper describes the dynamic performance of a wind-driven reluctance generator connected to an electric power network of large capacity. A controller that makes possible the regular flow of power to the network has been considered. Controller parameters that successfully suppress unwanted mechanical and electrical stresses and overshoots due to wind gusts, have been estimated. The performance of the controller has also been examined for short-circuit faults at the terminals of the generators.

Control and suppression of power transfer in couplersbyperiodic index modulation

Th authors show that evanescent power transfer between the cores of a four-port single-mode coupler can be controlled by periodic modulation of the refractive indices in the cores. In particular, the effective coupling can be completely suppressed, provided the index modulation amplitude and period satisfy certain conditions.

Thyristor-controlled quadrature boosting

With reference to the conventional quadrature booster transformer, this paper describes a way of achieving continuous phase-shift control based on point-on-wave thyristor switching. The proposed unit can provide continuous and practically instantaneous power-transfer control in transmission circuits. The theoretical waveforms are verified by experimental tests and computer studies. Consideration is also given to the harmonic content produced.

Design considerations for the high-power multicavity klystron

A confined-flow large-signal formulation of the klystron interaction equations is presented and applied to the analysis of the multicavity klystron amplifier. The effects of cavity voltage, cavity phase, drift length, and beam parameters are studied. The two- and three-cavity amplifiers are studied in detail, and several numerical examples of four-cavity klystrons are also given. A significant second-harmonic component of velocity modulation is shown to improve the dc to RF conversion efficiency. Two methods of obtaining this modulation are discussed. The large-signal theory presented here has been used to design a five-cavity klystron which is 50 percent efficient and has a controllable power transfer curve. Theoretical and experimental power transfer curves are presented for several 1 1/4-MW klystrons; the calculated output power is between 4 and 10 percent greater than the experimental values.