Stig Nilsson

HVDC transmission: yesterday and today

Basically, this paper takes a brief look at the history of HVDC to better understand its upcoming future. It also portrays some of the early developments in modern high-voltage direct current (HVDC) transmission. Today there are 16 DC links operating or under construction in the United States and 21 in North America. There are additionally numerous links throughout Scandinavia as well as in Japan, Australia, Brazil, South Africa, India, China, and others; well over 100 world wide. And, many others are planned, especially in India and China. HVDC transmission is an important contributor to successful power system operation. The history is interesting; after a period of comparative dormancy the future is unexpectedly bright

HVDC Circuit Breaker Development and Field Tests

With the growth of direct current transmission, the need and scope of application for a high voltage direct current circuit breaker have increased. This paper reports on the development of two different dc breaker prototypes and full scale field tests of these breakers on the ±400-kV, 1360-km long Pacific DC Intertie.

Pros and Cons of Integrating Protection and Control in Transmission Substations

It is generally accepted that the technology for integrating protection and control functions in transmission sub~ tations is here today, and many demonstration projects can testify to that fact.

Digital EHV Current Transducer

A digital electronic current transducer (ECT) has been developed under a project sponsored by The Electric Power Research Institute. The ECT features digital output, an optical fiber data transmission system, and a unique power supply located at high potential. The ECT meets or exceeds ANSI 0.3 accuracy class for metering, provides large dynamic range coupled with good accuracy for relaying use, and can be adapted to existing low-energy protective relays.

Operation of a Long-Term Transient Monitoring System in a 138-KV and a 500-KV Substation

This paper describes the operating performance of automatic transient monitoring laboratories designed to capture fault and transient data on power systems. Laboratories were installed in a 138-kV and a 500-kV substation and operated for more than 25,000 hours over a three-year period. Recorded during this period were 341 events consisting of lightning, switching, and faul t transients. These results provide invaluable data on actual transients in power systems to aid power system equipment designers. A summary of the transient data obtained with the laboratories is contained in a companion paper. This work was sponsored by Electric Power Research Institute under Contract RP751-1.

Summary of TTransient Data Obtained from Long-Term Monitoring of a 138-KV and a 500-KV Transmission Line

This paper presents a summary of transient data obtained during the monitoring of voltages and currents for a 138-kV and a 500-kV transmission line. The 341 transient events recorded during staged tests and unattended operation are grouped into three classes???lightning, switching, and fault. Significant examples are discussed in detail, and sample waveforms are presented. A description of the laboratories used to make the measurements is included in a companion paper. This work was sponsored by the Electric Power Research Institute under Contract RP751-1.This paper presents a summary of transient data obtained during the monitoring of voltages and currents for a 138-kV and a 500-kV transmission line. The 341 transient events recorded during staged tests and unattended operation are grouped into three cl asses--lightning, switching, and fault. Significant examples are discussed in detail, and sample waveforms are presehted. A description of the laboratories used to make the measurements is included in a companion paper. This work was sponsored by the Electric Power Research Institute under Contract RP751-1.

Technical Problems Associated with Developing HVDC Converter Stations for Voltages above 600 kV

This paper reviews the technical problems anticipated in the design construction and operation of HVDC converter stations in the voltage range ± 600-1200 kV. It is based on a literature review and discussions with experts from manufacturers and utilities. It concludes that 800 kV is a clearly feasible voltage step with existing knowledge, 1000 kV is practicable with further research effort, but that 1200 kV is unlikely to be economically feasible without a technological breakthrough. The principal problems identified are: 1) The behaviour of external insulation in bad weather, especially in polluted situations 2) Transformer insulation Controlled gas insulation 3) Surge arrester limitations Methods of controlling overvoltages.

A look at two textbooks (review of "Flexible Power Transmission: The HVDC Options" (Arrillaga, J. et al.; 2007) [Book review]

This book serves as an introductory textbook on power electronic applications for electric power transmission with emphasis on high-voltage dc systems. It also introduces some advanced HVDC converter concepts, which might find applications in dc transmission systems of the future. It is a useful book for those who need information about state of the art HVDC systems. It is not for system designers but most useful to those having a need to understand how the systems are designed.

Substation Equipment Diagnostics

Recent advances in signal processing techniques have paved the way for utilities to effectively meet the challenge of using existing assets more fully while maintaining traditional service reliability. Over the last 10 years, the authors institute has been applying these technological advances in the area of transmission substations to develop substation diagnostic devices and systems. Their involvement with transformer diagnostic is discussed in this paper.