Showing papers by "Neville R. Watson published in 2006"
TL;DR: In this article, an extension of harmonic domain modeling to flexible ac transmission system (FACTS) devices which contain series voltage injection elements is proposed, which is capable of modeling generic combinations of series and shunt converters; representing these elements as harmonic current and voltage sources, respectively.
Abstract: This paper outlines the extension of harmonic domain modeling to flexible ac transmission system (FACTS) devices which contain series voltage injection elements. The proposed iterative technique is capable of modeling generic combinations of series and shunt converters; representing these elements as harmonic current and voltage sources, respectively. The harmonic performance of these converter combinations is characterized in terms of dc current mismatches, which are combined with fundamental frequency power-flow mismatches in an iterative Newton solution. This combination maintains modularity, allowing multiple converter FACTS devices, such as the unified power-flow controller (UPFC), and/or systems containing multiple FACTS devices to be studied. The proposed technique has been successfully validated against time-domain simulation for the UPFC and then used to highlight converter interactions within a UPFC.
48 citations
TL;DR: In this paper, a self-commutating reinjection switch is used to force the thyristor valve currents to commutate independently from their respective line voltages, which adds reactive power controllability, as well as pulse multiplication.
Abstract: An old concept proposed to double the pulse number of a line commutated converter and designated "dc-ripple reinjection," is made more effective by the use of self-commutating reinjection switches, such as GTO or IGCT. It is shown that the self-commutating reinjection switches can be controlled to force the thyristor valve currents to commutate independently from their respective line voltages. EMTDC-PSCAD simulation is used to verify that this effect adds reactive power controllability, as well as pulse multiplication, to the conventional thyristor converter.
28 citations
TL;DR: An overview of the techniques currently available for the analysis of harmonic distortion in a large and complex electrical power system can be found in this article, where the effect of small harmonic sources is assessed.
Abstract: Advances in semiconductor technology have resulted in an escalation in the numbers and power ratings of non-linear loads connected to the power system. At all voltage levels, equipment is being installed which generates harmonics. At transmission levels, FACTS devices are being installed for controlling power flow, HVDC links are used to transfer real power between AC systems and large industries (aluminium smelters, steel manufacturing, etc.) are connected at these voltage levels, all of which introduce harmonics. At the other end of the scale, the increasing use of heat pumps, microwave ovens, PC, printers, stereos, TVs, compact fluorescent lamps in homes and commercial premises represents a dramatic increase in small harmonic sources. The effect of these harmonic sources needs to be assessed and this paper provides an overview of the techniques currently available for the analysis of harmonic distortion in a large and complex electrical power system.
12 citations
01 Sep 2006
TL;DR: In this article, a robust state estimator for power system containing unified power flow controller is presented, where the state estimation problem is formulated as an optimization problem using weighted least absolute value criteria, with a set of equality and inequality constraints.
Abstract: This paper presents a robust state estimator for power system containing unified power flow controller. The state estimation problem is formulated as an optimization problem using weighted least absolute value criteria, with a set of equality and inequality constraints. The interior point optimization method is applied to primal and dual formulation in order to solve this problem. The modified IEEE 14-bus system is used to demonstrate the effectiveness of the proposed algorithm. The simulation results indicate that the method yields good estimation of the system states for a power system with UPFC.
11 citations
28 Mar 2006
TL;DR: In this article, the structure and control of a new voltage source based HVDC transmission link are described, which uses multi-level voltage reinjection converters and offers some advantages over PWM-VSC transmission in terms of switching efficiency and valve ratings.
Abstract: The structure and control of a new voltage source based HVDC transmission link are described The link uses multi-level voltage reinjection converters It offers some advantages over PWM-VSC transmission in terms of switching efficiency and valve ratings, while providing similar levels of voltage and current waveform quality The waveforms and dynamic performance are verified by means of PSCAD/EMTDC simulation
10 citations
01 Oct 2006
TL;DR: In this paper, a multi-level current reinjection (MLC) scheme was proposed to provide acceptable harmonic reduction with fewer switching components than the conventional MLC scheme with reference to its performance when operated as a STATCOM, and the steady state and fast dynamic response to system changes, both under symmetrical and asymmetrical terminal voltage conditions.
Abstract: A multi-level current reinjection concept, already shown to provide acceptable harmonic reduction with fewer switching components than the conventional multi-level schemes, is described in this paper with reference to its performance when operated as a STATCOM. PSCAD/EMTDC is used to illustrate the steady state and fast dynamic response to system changes, both under symmetrical and asymmetrical terminal voltage conditions.
4 citations
01 Jan 2006
TL;DR: In this paper, a multi-level current reinjection (MLC) scheme was proposed to provide acceptable harmonic reduction with fewer switching components than the conventional MLC scheme with reference to its performance when operated as a STATCOM, and the steady state and fast dynamic response to system changes, both under symmetrical and asymmetrical terminal voltage conditions.
Abstract: A multi-level current reinjection concept, already shown to provide acceptable harmonic reduction with fewer switching components than the conventional multi-level schemes, is described in this paper with reference to its performance when operated as a STATCOM. PSCAD/EMTDC is used to illustrate the steady state and fast dynamic response to system changes, both under symmetrical and asymmetrical terminal voltage conditions.
2 citations
01 Jul 2006
TL;DR: In this paper, a self-commutating reinjection switch is used to force the thyristor valve currents to commutate independently from their respective line voltages, which adds reactive power controllability, as well as pulse multiplication.
Abstract: An old concept proposed to double the pulse number of a line commutated converter and designated "dc-ripple reinjection," is made more effective by the use of self-commutating reinjection switches, such as GTO or IGCT. It is shown that the self-commutating reinjection switches can be controlled to force the thyristor valve currents to commutate independently from their respective line voltages. EMTDC-PSCAD simulation is used to verify that this effect adds reactive power controllability, as well as pulse multiplication, to the conventional thyristor converter.
2 citations