EPE Association: EPE 1989 - 37 - Dialogue Session 2.4: ELECTRICAL POWER SUPPLIES

EPE 1989 - 37 - Dialogue Session 2.4: ELECTRICAL POWER SUPPLIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 37 - Dialogue Session 2.4: ELECTRICAL POWER SUPPLIES

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   CHARACTERISTICS OF CAPACITOR-FILTERED RECTIFYING POWER SUPPLY IN AC POWER LINE
By Duk-Gyoo Kim; Eisuke Masada [View]
[Download]

Abstract: The input current and the voltage of a capacitor-filtered rectifier, widely used as a power supply for a electronic home appliance, are calculated analytically with the impedance of the distribution system taken into consideration. Experimental results show good agreement with the calculation for the parameters variation.

   WIND ENERGY CONVERSION USING ASYNCHRONOUS GENERATORS
By E. S. Abdin; A.M. Sharaf; R. E. Burridge; O. H. Abdella [View]
[Download]

Abstract: The paper presents a simple digital microcomputer controller for the Wind Energy Conversion Scheme (WECS) comprising a self excited squirrel cage induction (asynchronous) generator. The wind scheme is interfaced to the electric utility grid via a current source inverter fed DC link scheme. The paper depicts the nonlinear model development, linearized controller design, simulation and laboratory prototype test results.

   SENSOR-LESS POWER CONTROL OF A DOUBLE-FED AC-MACHINE WITH NEARLY SINUSOIDAL LINE CURRENTS
By D. Arsudis; W. Vollstedt [View]
[Download]

Abstract: This paper describes a new field-oriented power control scheme for a double-fed ac-machine requiring no position sensor. Feeding slip power into the rotor circuit by a voltage source PWM converter, consisting of two six-pulse GTO circuits, almost sinusoidal grid currents are achieved. By adjusting the dc link voltage with rotor speed the effect of the switching time-delays of the inverter on the current harmonics can be hardly reduced.

   TERTIARY CONNECTED STATIC VAR COMPENSATORS FOR AC SYSTEM VOLTAGE CONTROL AND POWER OSCILLATION DAMPING
By Michael P. Häusler; Till Peter [View]
[Download]

Abstract: Autotransformers in HV networks can implement SVCs by connecting them to tertiary windings. This combination is presented with special consideration of control co-ordination. The priority oriented control strategy optimizes the application of inherent control facilities of both the SVC and the OLTC. It is shown that several tasks can be fulfilled with this scheme, such as:
- Power oscillation damping
- Dynamic voltage control (large system disturbances)
- Steady state voltage control (small system disturbances)
- VAR-control
The control strategy is based on the requirements of the AC system and considers the differences of control speed of the SVC and OLTC. The new control concept is already implemented in two SVC/OLTC schemes in China and Thailand in combination with 3 winding autotransformers. The behaviour of both control means, SVC and OLTC, is studied by means of digital computer programs for steady state operation and by simulations for transient operation using analog models for the network and static VAR compensator.

   COMMUTATION OVERVOLTAGES ON STATIC VAR COMPENSATORS
By Antonio G. G. Lima; Joao L. Alfonso [View]
[Download]

Abstract: The commutation overvoltages are one of the most important aspects of the design of a thyristor valve. The main purpose of this work was to obtain a more precise tool to evaluate these overvoltages. The theoretical aspects of the problem were revised and a digital thyristor model capable to simulate its dynamic characteristics was chosen. The simulated results obtained with this model together with the digital program SPICE were compared with the theoretical procedures and with laboratory results. Finally, the digital simulation procedure was used during the design of a prototype of thyristor's valve for a static var compensator.

   SOLID STATE EXCITATION SYSTEM OF AN AUTONOMOUS INDUCTION GENERATOR
By F. Crescimbini [View]
[Download]

Abstract: A new approach to the excitation of an autonomous induction generator supplying R-L loads is introduced. A PWM inverter supplying an extra three phase stator winding is employed to carry the reactive power required by the system while the main stator winding of the machine supplies the a.c. load. Stable self-excited steady state operations at constant frequency and voltage are achievable by controlling the slip. The magnatic nonlinearity of the machine is the key factor in the process of self-excitation, as well as the inverter and machine losses play an important role in determining the operating point of the system.

   FIRING AND CONDITION MONITORING SYSTEM OF A HIGH VOLTAGE THYRISTOR CONVERTOR FOR STATIC VAR COMPENSATOR
By S. Gyarmathy; G. Weiner [View]
[Download]

Abstract: With the increasing application of high voltage convertors, a need has arisen for improved firing and condition monitoring systems. This paper discusses a sophisticated system of this kind, which ensures simultaneous wide gate pulses with high gate current rate of rise for a plurality of series connected thyristors being at 10 kV potential, while continuously monitoring the condition of the system to prevent some failures or to reduce the effect of those. Practical results are presented to verify the effectiveness of the system.

   ISOLATED GRID FORMATION WITH PERMANENTLY-EXCITED SYNCHRONOUS GENERATOR FED BY A PULSE INVERTER
By J. Sachau [View]
[Download]

Abstract: In order to construct an isolated grid system with overload capability, that does not need fossil fuel prime-movers, a permanently-excited synchronous machine with increased rotating mass can be used in addition to a battery-fed pulse inverter. This configuration permits balancing of primary energy supply and load demand when utilising renewable energy. As the rotational speed control cannot be influenced by mechanically-controllable driving torque, the electrical moment is controlled in addition to the voltage. The controlled circuit model is derived, a decoupled control via the voltage vector is proposed, and its mode of operation explained with the assistance of simulations.

   THE HIGH-RATE COMPENSATOR OF THE REACTIVE POWER
By O. G. Bulatov; V. A. Shitov [View]
[Download]

Abstract: It is very hard to reach the electromagnetic compatibility between the user (consumer) and supply circuit due to the sharp dynamic and nonlinear load. For example, it takes place in electrotechnology, where there are nonlinear, nonsymmetrical, shock and high-repetition rate operation very often. One the decision of this problem to make the high speed compensation circuit of the reactive power.

EPE 1989 - 37 - Dialogue Session 2.4: ELECTRICAL POWER SUPPLIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 37 - Dialogue Session 2.4: ELECTRICAL POWER SUPPLIES
	[return to parent folder]

	CHARACTERISTICS OF CAPACITOR-FILTERED RECTIFYING POWER SUPPLY IN AC POWER LINE By Duk-Gyoo Kim; Eisuke Masada	[View] [Download]
Abstract: The input current and the voltage of a capacitor-filtered rectifier, widely used as a power supply for a electronic home appliance, are calculated analytically with the impedance of the distribution system taken into consideration. Experimental results show good agreement with the calculation for the parameters variation.

	WIND ENERGY CONVERSION USING ASYNCHRONOUS GENERATORS By E. S. Abdin; A.M. Sharaf; R. E. Burridge; O. H. Abdella	[View] [Download]
Abstract: The paper presents a simple digital microcomputer controller for the Wind Energy Conversion Scheme (WECS) comprising a self excited squirrel cage induction (asynchronous) generator. The wind scheme is interfaced to the electric utility grid via a current source inverter fed DC link scheme. The paper depicts the nonlinear model development, linearized controller design, simulation and laboratory prototype test results.

	SENSOR-LESS POWER CONTROL OF A DOUBLE-FED AC-MACHINE WITH NEARLY SINUSOIDAL LINE CURRENTS By D. Arsudis; W. Vollstedt	[View] [Download]
Abstract: This paper describes a new field-oriented power control scheme for a double-fed ac-machine requiring no position sensor. Feeding slip power into the rotor circuit by a voltage source PWM converter, consisting of two six-pulse GTO circuits, almost sinusoidal grid currents are achieved. By adjusting the dc link voltage with rotor speed the effect of the switching time-delays of the inverter on the current harmonics can be hardly reduced.

	TERTIARY CONNECTED STATIC VAR COMPENSATORS FOR AC SYSTEM VOLTAGE CONTROL AND POWER OSCILLATION DAMPING By Michael P. Häusler; Till Peter	[View] [Download]
Abstract: Autotransformers in HV networks can implement SVCs by connecting them to tertiary windings. This combination is presented with special consideration of control co-ordination. The priority oriented control strategy optimizes the application of inherent control facilities of both the SVC and the OLTC. It is shown that several tasks can be fulfilled with this scheme, such as: - Power oscillation damping - Dynamic voltage control (large system disturbances) - Steady state voltage control (small system disturbances) - VAR-control The control strategy is based on the requirements of the AC system and considers the differences of control speed of the SVC and OLTC. The new control concept is already implemented in two SVC/OLTC schemes in China and Thailand in combination with 3 winding autotransformers. The behaviour of both control means, SVC and OLTC, is studied by means of digital computer programs for steady state operation and by simulations for transient operation using analog models for the network and static VAR compensator.

	COMMUTATION OVERVOLTAGES ON STATIC VAR COMPENSATORS By Antonio G. G. Lima; Joao L. Alfonso	[View] [Download]
Abstract: The commutation overvoltages are one of the most important aspects of the design of a thyristor valve. The main purpose of this work was to obtain a more precise tool to evaluate these overvoltages. The theoretical aspects of the problem were revised and a digital thyristor model capable to simulate its dynamic characteristics was chosen. The simulated results obtained with this model together with the digital program SPICE were compared with the theoretical procedures and with laboratory results. Finally, the digital simulation procedure was used during the design of a prototype of thyristor's valve for a static var compensator.

	SOLID STATE EXCITATION SYSTEM OF AN AUTONOMOUS INDUCTION GENERATOR By F. Crescimbini	[View] [Download]
Abstract: A new approach to the excitation of an autonomous induction generator supplying R-L loads is introduced. A PWM inverter supplying an extra three phase stator winding is employed to carry the reactive power required by the system while the main stator winding of the machine supplies the a.c. load. Stable self-excited steady state operations at constant frequency and voltage are achievable by controlling the slip. The magnatic nonlinearity of the machine is the key factor in the process of self-excitation, as well as the inverter and machine losses play an important role in determining the operating point of the system.

	FIRING AND CONDITION MONITORING SYSTEM OF A HIGH VOLTAGE THYRISTOR CONVERTOR FOR STATIC VAR COMPENSATOR By S. Gyarmathy; G. Weiner	[View] [Download]
Abstract: With the increasing application of high voltage convertors, a need has arisen for improved firing and condition monitoring systems. This paper discusses a sophisticated system of this kind, which ensures simultaneous wide gate pulses with high gate current rate of rise for a plurality of series connected thyristors being at 10 kV potential, while continuously monitoring the condition of the system to prevent some failures or to reduce the effect of those. Practical results are presented to verify the effectiveness of the system.

	ISOLATED GRID FORMATION WITH PERMANENTLY-EXCITED SYNCHRONOUS GENERATOR FED BY A PULSE INVERTER By J. Sachau	[View] [Download]
Abstract: In order to construct an isolated grid system with overload capability, that does not need fossil fuel prime-movers, a permanently-excited synchronous machine with increased rotating mass can be used in addition to a battery-fed pulse inverter. This configuration permits balancing of primary energy supply and load demand when utilising renewable energy. As the rotational speed control cannot be influenced by mechanically-controllable driving torque, the electrical moment is controlled in addition to the voltage. The controlled circuit model is derived, a decoupled control via the voltage vector is proposed, and its mode of operation explained with the assistance of simulations.

	THE HIGH-RATE COMPENSATOR OF THE REACTIVE POWER By O. G. Bulatov; V. A. Shitov	[View] [Download]
Abstract: It is very hard to reach the electromagnetic compatibility between the user (consumer) and supply circuit due to the sharp dynamic and nonlinear load. For example, it takes place in electrotechnology, where there are nonlinear, nonsymmetrical, shock and high-repetition rate operation very often. One the decision of this problem to make the high speed compensation circuit of the reactive power.