EPE Association: EPE 1989 - 13 - Lecture Session 2.6: POWER ELECTRONICS IN GENERATION AND TRANSMISSION

EPE 1989 - 13 - Lecture Session 2.6: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
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   DC OVERVOLTAGE PHENOMENA IN GTO LARGE-SCALE LINE INTERACTIVE POWER CONDITIONING SYSTEM
By N. Seki; Y. Ogawa; O. Higa [View]
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Abstract: DC overvoltage phenomena were observed in the utility line interactiva operation of the world's largest 12-MW PWM GTO power conditioning system (PCS). The phenomena, peculiar to a system where a phase multiplication method using serially connected zigzag windings of plural transformers is employed, appear in two states. One occurs at the instant the transformers are connected to the line with the inverter gate blocked, and the other oçcurs in the steady state after transient. This paper describes a computer simulation using EMTP (ElectroMagnetic Transient Program) and discusses the overvoltage causes. The overvoltage is caused by the distorted voltages of the transformers due to magnetic saturation and restricted exciting current. Some corrective measures for the dc overvoltage were taken, after which the PCS operated properly.

   DOES GTO MAKE A DIFFERENCE? CURRENT SOURCE INVERTER OF 1984 VS CURRENT SOURCE GTO-PWM INVERTER OF 1988 RESULTS OF ASD TESTS ON 2000 HP BOILER FEED PUMP MOTORS
By James A. Oliver; Marek J. Samotyj [View]
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Abstract: This paper reports on the results of adjustable speed drive units being used for the same boiler feed pump applications in the same 2000 HP range, employing current source inverter topology, but with inverter technology of the second unit several generations advanced over the first. At Sierra Pacific Power Company' s 110 MW Ft. Churchill Plant, unit 2, a 2000 HP current source 12-pulse system has been operating since 1984. At their Tracy Plant, Unit 3, a 6-pulse GTO PWM current source system went into service in 1988. Both ASOs were tested on site by Bechtel for EPRI as part of their ASD field test program. Power savings, ASO technology development, level of harmonics, cooling system and testing method are discussed.

   HIGH-EFFICIENCY SOLAR PANEL / WIND TURBINE CONVERTER WITH MAXIMAL POWER CONTROL
By P. D. van den Heever; J. H. R. Enslin [View]
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Abstract: A high-efficiency boost converter for converting the output voltage of a solar panel array, or wind turbine, to the required dc bus voltage, feeding a battery bank and an inverter, is described. The series inclusion of the converter necessitates a high efficiency, therefore the first objective is the maximization of the energy efficiency of the converter. This is attained by effective power switch driving, implementing a regenerative snubber, using low loss core material and utilizing Schottky diodes. A comparative investigation between bipolar transistors and field effect transistors as switching elements, is made towards total converter efficiency. In order to maximize the overall efficiency of the renewable energy system, it is necessary to track the maximum power point of the input source. Maximum power tracking is achieved by measurements of the output current and voltage, calculating and maximizing output power. The batteries which serve as an energy store are expensive and therefore necessitates some form of charging and discharging protection. This is achieved by limiting the maximum allowable charge current to a value which depends on the battery state of charge.

EPE 1989 - 13 - Lecture Session 2.6: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 13 - Lecture Session 2.6: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
	[return to parent folder]

	DC OVERVOLTAGE PHENOMENA IN GTO LARGE-SCALE LINE INTERACTIVE POWER CONDITIONING SYSTEM By N. Seki; Y. Ogawa; O. Higa	[View] [Download]
Abstract: DC overvoltage phenomena were observed in the utility line interactiva operation of the world's largest 12-MW PWM GTO power conditioning system (PCS). The phenomena, peculiar to a system where a phase multiplication method using serially connected zigzag windings of plural transformers is employed, appear in two states. One occurs at the instant the transformers are connected to the line with the inverter gate blocked, and the other oçcurs in the steady state after transient. This paper describes a computer simulation using EMTP (ElectroMagnetic Transient Program) and discusses the overvoltage causes. The overvoltage is caused by the distorted voltages of the transformers due to magnetic saturation and restricted exciting current. Some corrective measures for the dc overvoltage were taken, after which the PCS operated properly.

	DOES GTO MAKE A DIFFERENCE? CURRENT SOURCE INVERTER OF 1984 VS CURRENT SOURCE GTO-PWM INVERTER OF 1988 RESULTS OF ASD TESTS ON 2000 HP BOILER FEED PUMP MOTORS By James A. Oliver; Marek J. Samotyj	[View] [Download]
Abstract: This paper reports on the results of adjustable speed drive units being used for the same boiler feed pump applications in the same 2000 HP range, employing current source inverter topology, but with inverter technology of the second unit several generations advanced over the first. At Sierra Pacific Power Company' s 110 MW Ft. Churchill Plant, unit 2, a 2000 HP current source 12-pulse system has been operating since 1984. At their Tracy Plant, Unit 3, a 6-pulse GTO PWM current source system went into service in 1988. Both ASOs were tested on site by Bechtel for EPRI as part of their ASD field test program. Power savings, ASO technology development, level of harmonics, cooling system and testing method are discussed.

	HIGH-EFFICIENCY SOLAR PANEL / WIND TURBINE CONVERTER WITH MAXIMAL POWER CONTROL By P. D. van den Heever; J. H. R. Enslin	[View] [Download]
Abstract: A high-efficiency boost converter for converting the output voltage of a solar panel array, or wind turbine, to the required dc bus voltage, feeding a battery bank and an inverter, is described. The series inclusion of the converter necessitates a high efficiency, therefore the first objective is the maximization of the energy efficiency of the converter. This is attained by effective power switch driving, implementing a regenerative snubber, using low loss core material and utilizing Schottky diodes. A comparative investigation between bipolar transistors and field effect transistors as switching elements, is made towards total converter efficiency. In order to maximize the overall efficiency of the renewable energy system, it is necessary to track the maximum power point of the input source. Maximum power tracking is achieved by measurements of the output current and voltage, calculating and maximizing output power. The batteries which serve as an energy store are expensive and therefore necessitates some form of charging and discharging protection. This is achieved by limiting the maximum allowable charge current to a value which depends on the battery state of charge.