Colin D. Schauder

Development of a /spl plusmn/100 MVAr static condenser for voltage control of transmission systems

The availability of high power gate-turn-off (GTO) thyristors has led to the development of controllable reactive power sources, using electronic switching power converters, for use in power transmission systems. This new technology has resulted in equipment that is fundamentally different from the conventional thyristor-controlled static VAr compensator (SVC). The new equipment is called a static condenser (STATCON) because its steady state output characteristics are similar to those of the rotating synchronous condenser. The paper describes the fundamental operating principles, functional characteristics and basic control approach of the STATCON, with particular reference to a /spl plusmn/100 MVAr prototype planned to be installed at the Tennessee Valley Authority (TVA) Sullivan substation, USA. This installation will be the first demonstration of a STATCON under the EPRI flexible AC transmission systems (FACTS) program, and will be the largest installation of its type in the world. >

Theory and design of a 30-hp matrix converter

A description is given of the control strategy and hardware design for a 30-hp matrix converter (9-switch forced-commutation cycloconverter), which was developed for high-bandwidth four-quadrant-motor drive applications. The switching technique ensures very low distortion of the input currents with unity fundamental displacement factor. Experimental results are presented.<<ETX>>

AEP UPFC project: installation, commissioning and operation of the /spl plusmn/160 MVA STATCOM (phase I)

American Electric Power (AEP) has selected its Inez Substation in eastern Kentucky for the location of the worlds first Unified Power Flow Controller (UPFC) installation. Comprising two /spl plusmn/160 MVA voltage-sourced GTO-thyristor-based inverters, this installation is not only the first practical demonstration of the UPFC concept, but also by far the highest power GTO-based Flexible AC Transmission Systems (FACTS) equipment ever installed. The installation will be the first demonstration of this type of equipment connected in series with a transmission line. The project is a collaborative effort between AEP, the Westinghouse Electric Corporation, and the Electric Power Research Institute (EPRI), and has been divided into two phases corresponding to the installation of the shunt- and series-connected inverters respectively. Phase I (installation and commissioning of the shunt inverter (STATCOM)) was completed successfully in July, 1997, and the STATCOM is now operational. Phase II is scheduled for completion in early 1998. This paper gives a brief background to the project, describes the installation and special features of the equipment, and reports on the Phase I commissioning and STATCOM operation.

Operation of /spl plusmn/100 MVAr TVA STATCON

In 1995 a /spl plusmn/100 MVA static synchronous compensator (STATCON) was commissioned for the Tennessee Valley Authority (TVA) at the Sullivan substation in North-Eastern Tennessee, USA. This was an historic milestone in the initiative for flexible AC transmission systems (FACTS) promoted by the Electric Power Research Institute (EPRI). The TVA STATCON is the first of its kind, using GTO thyristor valves, to be commissioned in the United States, and is currently the largest installation of this type in the world. Commissioning tests have now been completed and the STATCON is operating continuously online. The demonstrated performance of the equipment has either met or exceeded expectations in all areas and has proven beyond doubt the viability of this type of equipment in high power transmission systems. This paper briefly reviews the STATCON installation and reports on the static and dynamic performance observed during commissioning.

Current Control of Voltage-Source Inverters for Fast Four-Quadrant Drive Performance

A rotating reference frame controller for ac machines which enables smooth four-quadrant drive operation with good torgue control bandwidth is described. The advantages which result from the control of stator magnetomotive force (MMF) in a rotor reference frame are illustrated with regard to synchronous and induction motors. The application of this method to a cycloconverter synchronous motor drive is outlined.

High Performance Torque-Controlled Induction Motor Drives

The way in which a practical control method using derived torque feedback signal has made it possible to obtain the same high bandwidth torque control with standard cage induction motors as can be achieved with dc motors is demonstrated. In contrast with previous torque control systems, this method does not require the angular position of a motor field vector to be determined for control purposes. The versatility of this torque controller is illustrated with measured torque responses obtained from a transitorized servo drive, a cycloconvertor, and a current source inverter.

A regenerative two-quadrant converter for DC-link voltage source inverters

A regenerative two-quadrant power converter which is suitable for interfacing between the AC mains and the DC link of a voltage source inverter is described. The circuit provides highly reliable commutation in the regeneration mode using only a single fully controlled static switch and a minimum configuration of thyristors and diodes. The circuit has been applied successfully in commercial PWM (pulsewidth-modulated) inverter products with power ratings up to 160 hp.<<ETX>>