Switching circuits with thyristor controlled reactors are used in high power systems for static V... more Switching circuits with thyristor controlled reactors are used in high power systems for static VAR control and flexible AC transmission. These circuits can exhibit highly nonlinear behavior because the thyristor switch off time depends on the circuit state. This paper shows how to understand and predict damping and resonance in a basic thyristor controlled reactor circuit used for static VAR control. The circuit damping occurs even in the absence of circuit resistance. An analytic formula for the circuit Jacobian is studied to predict resonance effects and a simple test for detecting resonance involving circuit frequencies spanning an integer harmonic is proven to be correct.
PESC `92 Record. 23rd Annual IEEE Power Electronics Specialists Conference
The classical analysis is often applicable, but can, as demonstrated here and in [1,5], fail for ... more The classical analysis is often applicable, but can, as demonstrated here and in [1,5], fail for certain circuit parameters and operating conditions. Under these conditions, both the voltage and the current waveforms become greatly distorted with large harmonic components. This distortion is associated with a resonance phenomenon in which the natural frequencies of the circuit, from when the reactor is fully on to when it is fully off, span an odd harmonic. This harmonic distortion can lead to instabilities as switching times suddenly
The IMA Volumes in Mathematics and its Applications, 1995
Switching circuits with thyristor controlled reactors are used in high power systems for static V... more Switching circuits with thyristor controlled reactors are used in high power systems for static VAR control and flexible AC transmission. These circuits can exhibit highly nonlinear behavior because the thyristor switch off time depends on the circuit state. This paper shows how to understand and predict damping and resonance in a basic thyristor controlled reactor circuit used for static VAR control. The circuit damping occurs even in the absence of circuit resistance. An analytic formula for the circuit Jacobian is studied to predict resonance effects and a simple test for detecting resonance involving circuit frequencies spanning an integer harmonic is proven to be correct.
IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 1996
We study a thyristor controlled reactor circuit used for static VAR control of utility electric p... more We study a thyristor controlled reactor circuit used for static VAR control of utility electric power systems. The circuit exhibits switching times which jump or bifurcate as fold or transcritical bifurcations. We study the nonlinear dynamics of the circuit using a Poincare map and demonstrate that the Poincare map has discontinuities and is not invertible. The circuit has multiple attractors,
Over the last couple of years there has been significant activity in the development of Flexible ... more Over the last couple of years there has been significant activity in the development of Flexible AC Transmission Systems (FACTS). Much of this work has been directed towards advanced series compensation (ASC) systems based on a Thyristor Controlled Reactor (TCR) ...
1993 IEEE International Symposium on Circuits and Systems
The authors study a general RLC circuit with ideal diodes and periodic sources by computing the J... more The authors study a general RLC circuit with ideal diodes and periodic sources by computing the Jacobian of the Poincare/spl acute/ map. These circuits are nonlinear but have special structure allowing the Jacobian to be reduced to a simple and useful expression. The Jacobian computation is illustrated with a diode bridge rectifier circuit.<<ETX>>
of the power systems in network planning is likely to lead This paper discusses the merits of an ... more of the power systems in network planning is likely to lead This paper discusses the merits of an analytical method for to higher system costs and reduced reliability. This paper determining the location and amount of series addresses transmission capability limits and concerns itself compensation to increase the steady state power transfer primarily with planning decisions. capability in the power system based primarily on cascading line overload considerations. Steady state transmission limits deJne the boundaries of a power system operating point. This paper presents tools to identi3 these boundaries and analytically estimates the change in the boundary limits due to the application of series and shunt compensation. The approach identiJies critical lines that can initiate cascading line outages and identifies the optimal location and amount for series compensation. The methodology can also be used to select sites for devices that can extend the mailability ofpower in $0 wgates.
This paper computes the small signal dynamic response of a thyristor controlled series capacitor ... more This paper computes the small signal dynamic response of a thyristor controlled series capacitor system for use in control design. The computation includes the effects of synchronization and the nonlinearity due to thyristor switchings. Eigenvalues of the small signal dynamic response are computed and used to study the dynamic response of the Kayenta system using different methods of synchronization and a closed loop control.
PESC '91 Record 22nd Annual IEEE Power Electronics Specialists Conference, 1991
Tools are developed to study the harmonic interactions of a single-phase, fine commutated convert... more Tools are developed to study the harmonic interactions of a single-phase, fine commutated converter with power systems. It is shown that the classical method of analysis is incorrect when dealing with systems close to resonance points. For example, the operation of such a converter with the rest of the power system can have two solutions and/or no solutions for regions which the classical method predicts both existence and uniqueness of solutions
Tools are developed to study the harmonic interactions of a single-phase, fine commutated convert... more Tools are developed to study the harmonic interactions of a single-phase, fine commutated converter with power systems. It is shown that the classical method of analysis is incorrect when dealing with systems close to resonance points. For example, the operation of such a converter with the rest of the power system can have two solutions and/or no solutions for regions which the classical method predicts both existence and uniqueness of solutions
Two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. ... more Two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. One power conditioning system is based on a hybrid current sourced inverter (CSI), the second is a combination of a DC chopper with a voltage sourced inverter (VSI). Both of these systems have independent control of real and reactive power. These systems have a significant reduction in MVA rating levels as related to the more traditional Graetz bridge
The dynamic response of two power conditioning systems for superconductive magnetic energy storag... more The dynamic response of two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. One power conditioning system is based on a hybrid current sourced inverter (CSI), the second is a combination of a DC chopper with a voltage sourced inverter (VSI). The response of both systems to a load change, a three phase fault, and start-up is
Abstract-Thyristor controlled reactors are high power switch-ing circuits used for static VAR con... more Abstract-Thyristor controlled reactors are high power switch-ing circuits used for static VAR control and the emerging tech-nology of flexible ac transmission. The static VAR control circuit considered in the paper is a nonlinear periodically operated RLC circuit with a sinusoidal source and ideal thyristors with equidistant firing pulses. This paper describes new instabilities in the circuit in which thyristor turn off times jump or bifurcate as a system parameter varies slowly. The new instabilities are called switching time bifurcations and are fold bifurcations of zeros of thyristor current. The bifurcation instabilities are explained and verified by simulation and an experiment. Switching time bifurcations are special to switching systems and, surprisingly, are not conventional bifurcations. In particular, switching time bifurcations cannot be predicted by observing the eigenvalues of the system Jacobian. We justify these claims by deriving a simple formula for the Jacobian of ...
This paper develops an accurate and general stability model for the ASC (thyristor controlled rea... more This paper develops an accurate and general stability model for the ASC (thyristor controlled reactor). The model is valid for both the capacitive and inductive regions of the ASC operation. It is accurate in that the instantaneous voltage and current waveforms and ...
Switching circuits with thyristor controlled reactors are used in high power systems for static V... more Switching circuits with thyristor controlled reactors are used in high power systems for static VAR control and flexible AC transmission. These circuits can exhibit highly nonlinear behavior because the thyristor switch off time depends on the circuit state. This paper shows how to understand and predict damping and resonance in a basic thyristor controlled reactor circuit used for static VAR control. The circuit damping occurs even in the absence of circuit resistance. An analytic formula for the circuit Jacobian is studied to predict resonance effects and a simple test for detecting resonance involving circuit frequencies spanning an integer harmonic is proven to be correct.
PESC `92 Record. 23rd Annual IEEE Power Electronics Specialists Conference
The classical analysis is often applicable, but can, as demonstrated here and in [1,5], fail for ... more The classical analysis is often applicable, but can, as demonstrated here and in [1,5], fail for certain circuit parameters and operating conditions. Under these conditions, both the voltage and the current waveforms become greatly distorted with large harmonic components. This distortion is associated with a resonance phenomenon in which the natural frequencies of the circuit, from when the reactor is fully on to when it is fully off, span an odd harmonic. This harmonic distortion can lead to instabilities as switching times suddenly
The IMA Volumes in Mathematics and its Applications, 1995
Switching circuits with thyristor controlled reactors are used in high power systems for static V... more Switching circuits with thyristor controlled reactors are used in high power systems for static VAR control and flexible AC transmission. These circuits can exhibit highly nonlinear behavior because the thyristor switch off time depends on the circuit state. This paper shows how to understand and predict damping and resonance in a basic thyristor controlled reactor circuit used for static VAR control. The circuit damping occurs even in the absence of circuit resistance. An analytic formula for the circuit Jacobian is studied to predict resonance effects and a simple test for detecting resonance involving circuit frequencies spanning an integer harmonic is proven to be correct.
IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 1996
We study a thyristor controlled reactor circuit used for static VAR control of utility electric p... more We study a thyristor controlled reactor circuit used for static VAR control of utility electric power systems. The circuit exhibits switching times which jump or bifurcate as fold or transcritical bifurcations. We study the nonlinear dynamics of the circuit using a Poincare map and demonstrate that the Poincare map has discontinuities and is not invertible. The circuit has multiple attractors,
Over the last couple of years there has been significant activity in the development of Flexible ... more Over the last couple of years there has been significant activity in the development of Flexible AC Transmission Systems (FACTS). Much of this work has been directed towards advanced series compensation (ASC) systems based on a Thyristor Controlled Reactor (TCR) ...
1993 IEEE International Symposium on Circuits and Systems
The authors study a general RLC circuit with ideal diodes and periodic sources by computing the J... more The authors study a general RLC circuit with ideal diodes and periodic sources by computing the Jacobian of the Poincare/spl acute/ map. These circuits are nonlinear but have special structure allowing the Jacobian to be reduced to a simple and useful expression. The Jacobian computation is illustrated with a diode bridge rectifier circuit.<<ETX>>
of the power systems in network planning is likely to lead This paper discusses the merits of an ... more of the power systems in network planning is likely to lead This paper discusses the merits of an analytical method for to higher system costs and reduced reliability. This paper determining the location and amount of series addresses transmission capability limits and concerns itself compensation to increase the steady state power transfer primarily with planning decisions. capability in the power system based primarily on cascading line overload considerations. Steady state transmission limits deJne the boundaries of a power system operating point. This paper presents tools to identi3 these boundaries and analytically estimates the change in the boundary limits due to the application of series and shunt compensation. The approach identiJies critical lines that can initiate cascading line outages and identifies the optimal location and amount for series compensation. The methodology can also be used to select sites for devices that can extend the mailability ofpower in $0 wgates.
This paper computes the small signal dynamic response of a thyristor controlled series capacitor ... more This paper computes the small signal dynamic response of a thyristor controlled series capacitor system for use in control design. The computation includes the effects of synchronization and the nonlinearity due to thyristor switchings. Eigenvalues of the small signal dynamic response are computed and used to study the dynamic response of the Kayenta system using different methods of synchronization and a closed loop control.
PESC '91 Record 22nd Annual IEEE Power Electronics Specialists Conference, 1991
Tools are developed to study the harmonic interactions of a single-phase, fine commutated convert... more Tools are developed to study the harmonic interactions of a single-phase, fine commutated converter with power systems. It is shown that the classical method of analysis is incorrect when dealing with systems close to resonance points. For example, the operation of such a converter with the rest of the power system can have two solutions and/or no solutions for regions which the classical method predicts both existence and uniqueness of solutions
Tools are developed to study the harmonic interactions of a single-phase, fine commutated convert... more Tools are developed to study the harmonic interactions of a single-phase, fine commutated converter with power systems. It is shown that the classical method of analysis is incorrect when dealing with systems close to resonance points. For example, the operation of such a converter with the rest of the power system can have two solutions and/or no solutions for regions which the classical method predicts both existence and uniqueness of solutions
Two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. ... more Two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. One power conditioning system is based on a hybrid current sourced inverter (CSI), the second is a combination of a DC chopper with a voltage sourced inverter (VSI). Both of these systems have independent control of real and reactive power. These systems have a significant reduction in MVA rating levels as related to the more traditional Graetz bridge
The dynamic response of two power conditioning systems for superconductive magnetic energy storag... more The dynamic response of two power conditioning systems for superconductive magnetic energy storage (SMES) are presented. One power conditioning system is based on a hybrid current sourced inverter (CSI), the second is a combination of a DC chopper with a voltage sourced inverter (VSI). The response of both systems to a load change, a three phase fault, and start-up is
Abstract-Thyristor controlled reactors are high power switch-ing circuits used for static VAR con... more Abstract-Thyristor controlled reactors are high power switch-ing circuits used for static VAR control and the emerging tech-nology of flexible ac transmission. The static VAR control circuit considered in the paper is a nonlinear periodically operated RLC circuit with a sinusoidal source and ideal thyristors with equidistant firing pulses. This paper describes new instabilities in the circuit in which thyristor turn off times jump or bifurcate as a system parameter varies slowly. The new instabilities are called switching time bifurcations and are fold bifurcations of zeros of thyristor current. The bifurcation instabilities are explained and verified by simulation and an experiment. Switching time bifurcations are special to switching systems and, surprisingly, are not conventional bifurcations. In particular, switching time bifurcations cannot be predicted by observing the eigenvalues of the system Jacobian. We justify these claims by deriving a simple formula for the Jacobian of ...
This paper develops an accurate and general stability model for the ASC (thyristor controlled rea... more This paper develops an accurate and general stability model for the ASC (thyristor controlled reactor). The model is valid for both the capacitive and inductive regions of the ASC operation. It is accurate in that the instantaneous voltage and current waveforms and ...
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