HVDC Thyristor Valves Research Articles

Reverse recovery characteristics of high power thyristors in HVDC converter valve

The reverse recovery characteristics of high power thyristor are important device physical properties influencing the reliable operation of HVDC thyristor valve. In this paper, the reverse recovery characteristics of high power thyristor are investigated from the aspects of both external circuit and internal device physics. By analyzing the depletion of carrier during the reverse recovery of thyristors, a determination method of minority carrier lifetime is proposed to construct a connection between the macroscopic reverse recovery characteristics and the microscopic device physical parameter such as minority carrier lifetime. Meanwhile, the influence of the current with a power frequency on the characteristics of reverse recovery especially on the reverse recovery time is investigated experimentally, and the relationship between external circuit and internal physical property is discussed. The results show that thyristor reverse recovery storage time is independent of sinusoidal currents under power frequency, which is approximately equal to its minority carrier lifetime in the base region of high power thyristors; Finally, the influences of reverse recovery characteristics on the protection strategy of thyristor unit are analyzed, and the related methods of thyristor unit routine test are also discussed. This work will be beneficial to the operational maintenance of thyristor valve in power system.

보조 사이리스터의 턴-오프 회로를 간소화한 HVDC 사이리스터 밸브 시험용 합성시험회로

This study proposes a new synthetic test circuit (STC) for HVDC thyristor valve tests. The conventional STC with a 2-phase chopper requires a 3-phase transformer, a 3-phase diode rectifier, and an IGBT to facilitate the off state of an auxiliary thyristor. In the proposed STC, these three components are replaced with one diode and one resistor, which result in the simplified implementation of the hardware of the STC. Simulation and experimental results demonstrate the validity of the proposed scheme.

Corrosion in HVDC valve cooling systems

Stainless steel couplings in the main cooling water pipes of HVDC thyristor valves have been in use since 1983, with overall satisfactory behavior. However, some water leakage due to corrosion below the sealing O-rings of the couplings was observed during 1992. An extensive investigation and follow-up worldwide showed a direct correlation between water quality and the corrosion rate of these stainless steel couplings. Recommendations are given as to actions to be taken in order to maintain a long lifetime for the fine water systems.

Water cooling of HVDC thyristor valves

It is generally accepted that water is a very effective medium to remove heat losses from any type of equipment. When used for HVDC thyristor valves, the fundamentals of electrolyte conduction and water chemistry need to be considered in the design of the cooling circuit. The characteristics of the materials used, in conjunction with high voltage stresses and circuit configuration, play an important role to assure longevity and corrosion-free performance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Loss determination of HVDC thyristor valves

Losses in HVDC thyristor valves are an important economic factor, but their verification by direct electrical measurement is not practical. The origin and method of dissipation of valve losses is described, and alternative methods for valve loss verification are reviewed. The most economic and reliable method appears to be the summation of calculated component losses.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Alternative method for evaluation of damping circuit losses in HVDC thyristor valves

An accurate method for calculating the damping circuit losses in HVDC converter systems is proposed. It is based on an equivalent circuit representation of the converter system during each interval of conduction over a power frequency period. The results are compared with the results obtained by the approximate formula proposed by J.D. Ainsworth and with the results obtained using the second-order approximate model to simulate valve voltage oscillations during each commutation. The variation of damping circuit loss with bridge operating parameters and with the damping parameters is also analyzed. >

A practical design for an integrated HVDC unit-connected hydro-electric generating station

The cost of a significant amount of plant and facilities found in conventional schemes can be eliminated by integrating HVDC substations directly with generating units. The results of a study to quantify these benefits are outlined. An actual hydroelectric power station design was used, incorporating a HVDC thyristor valve scheme in a hypothetical situation. The financial and other benefits determined for this example are presented together with conclusions and recommendations for future projects and further areas of study.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A Unit Arrester Application for HVDC Thyristor Valve

A Unit Arrester Application for HVDC Thyristor Valve

A Unit Arrester Application for HVDC Thyristor Valve

As an overvoltage protection for the HVDC thyristor valve a method of connecting a unit arrester to each thyristor is presented. A study was conducted to investigate how far the necessary thyristor series number in the valve could be reduced by this method.

Development Of HVDC Thyristor Valve Insulated And Cooled By Compressed SF6 Gas

A thyristor valve for HVDC transmission insulated by compressed SF 6 gas has been developed. The valve is cooled by the forced circulation of the insulating gas with a blower. Valve unit up to the voltage and current ratings of 250 kV and 3,000 A can be housed in a metal tank and the valve is transportable on a trailer fully constructed. A metal enclosed converter for 500 kV HVDC power transmission for example, may be constructed by connecting the units to form a twelve pulse converter.

Development of HVDC Thyristor Valve Insulated and Cooled by Compressed SF6 Gas

Development of HVDC Thyristor Valve Insulated and Cooled by Compressed SF₆ Gas

Behavior of HVDC Thyristor Valve on the Critical Turn-Off Condition and Optimized Gate Firing System

Behavior of HVDC Thyristor Valve on the Critical Turn-Off Condition and Optimized Gate Firing System

Behavior of HVDC Thyristor Valve on the Critical Turn-Off Condition and Optimized Gate Firing System

When a thyristor valve is operated in a current discontinuity mode, one or more thyristor devices of the valve can be overstressed due to the critical, turn-off phenomena. An adequate gate firing s stem is indispensable to y prevent such a thyristor contingency. In thi. s paper, a thyristor critical turn-off is discussed in detail and the optimized gate system is presented with the demonstration of site test carried out in Hokkaido ?Honshu HVDC link in Japan.

A Proposed Test Specification for HVDC Thyristor Valves

This paper presents a proposal for a test specification for HVDC thyristor valves. The test specifiation includes a discussion of the criteria for successful type testing, a proposal for selection of test withstand voltage levels and a description of proposed dielectric and operational tests. The dielectric tests are intended to verify the withstand and other voltage-related characteristics of the valve and the operational tests are intended to demonstrate the correct operation and capabilities of the valve under various operating conditions including critical faults. The test series consist of type tests and production sample tests performed at the manufacturer's test facilities prior to shipment. Manufacturer's equipment development tests, routine factory tests, commissioning tests and other site tests are not within the scope of the test specification, and hence are not included.

Dielectric Behavior of the Coolant for a Gas Insulated HVDC Thyristor Valve

The objective of this paper is to report on studies made on a fullscale model of the coolant system for a gas insulated, fluorocarbon liquid cooled HVDC thyristor valve. Confidence in the selection of the coolant system and its associated dielectric containment structure stemmed from the parametric study of the coolant, and the more than adequate dielectric strength of the coolant even when it was in the cavitated state. An explanation is proposed on the apparent anomoly of the exceptional dielectric strength of the system, even when bubble nucleation is induced by the injection of a dielectrically weak (nitrogen) gas into the flowing coolant.

Analysis of the Cable Firing System for HVDC Thyristor Values

The firing of a HVDC thyristor valve, where several hundred thyristors are interconnected in a series-parallel combination, presents a number of fundamental problems related to the generation, transmission and reshaping of the signal. This paper presents an analysis of these problems and proposes a cable firing system suitable for HVDC thyristor valves. A calculation method of evaluating the system performance and an optimization of the system parameters are given. Also, experimental results are presented which show the actual performance of the proposed firing system on a 150-kV, 600 A thyristor valve.

A method for calculating the reliability of hvdc thyristor valves

A method for calculating the reliability of hvdc thyristor valves

Solutions for problems caused by the distributed stray capacitance of oil‐cooled and oil‐immersed HVDC thyristor valves

Electrical Engineering in JapanVolume 92, Issue 2 p. 64-68 Article Solutions for problems caused by the distributed stray capacitance of oil-cooled and oil-immersed HVDC thyristor valves K. Tada, K. Tada (Member) Mitsubishi Electric CorporationSearch for more papers by this authorH. Mitsuoka, H. Mitsuoka (Member) Mitsubishi Electric CorporationSearch for more papers by this author K. Tada, K. Tada (Member) Mitsubishi Electric CorporationSearch for more papers by this authorH. Mitsuoka, H. Mitsuoka (Member) Mitsubishi Electric CorporationSearch for more papers by this author First published: 1972 https://doi.org/10.1002/eej.4390920208AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume92, Issue21972Pages 64-68 RelatedInformation