Rectifier Installations Research Articles

On Harmonic Currents and Voltages on the Supply Circuits for Mercury Arc Rectifier Installations

On Harmonic Currents and Voltages on the Supply Circuits for Mercury Arc Rectifier Installations

Conversion equipment in the du Pont company

The apparatus for the conversion of a-c to d-c power in various plants of the du Pont Company has included rotary converters, motor generator sets, and mercury-arc rectifiers. Operation and maintenance of this equipment since the company's first converters were installed in 1895 to present rectifier installations has provided much valuable experience and information.

Operation in metallurgical and chemical plants

CONSOLIDATED Mining and Smelting Company of Canada, Ltd., metallurgical and chemical plants, located at Trail, British Columbia, have a total load of 180,000 kw of which 80 per cent is converted to direct current for use in electrolytic processes. The first rectifier installation went into operation in 1929. Further installations have been added and now 70 per cent of the installed conversion equipment consists of mercury-arc rectifiers.

Inductive Co-ordination Aspects of RectiFier Installations

Discussion of paper 46-105, an AlEE committee report, presented at the AlEE summer convention, Detroit, Mich., June 24-28, 1946, and published in AIEE TRANSACTIONS, 1946, July section, pages 417-36.

Inductive co-ordination aspects of rectifier installations

Inductive co-ordination aspects of rectifier installations

Inductive Co-ordination Aspects of Rectifier Installations

Inductive Co-ordination Aspects of Rectifier Installations

Inductive co-ordination aspects of rectifier installations

Inductive co-ordination aspects of rectifier installations

Anode-circuit-breaker design and performance criteria

THE rapidly expanding use of mercury-arc rectifiers, both as to total installed capacity and the relatively large number of units operating in parallel, emphasizes the importance of suitable switch-gear to provide over-all satisfactory rectifier operation. The necessity for such switch-gear, particularly for a high-speed air circuit breaker in the rectifier anode circuit, has been outlined in previous papers before the Institute. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,2</sup> During the past several years, considerable progress has been made in the reduction of arc-backs in power rectifiers. Anode circuit breakers, although subject to less frequent duty as a result of this progress, are required to operate at higher voltages and interrupt greater arc-back currents as indicated by recorded rates of rise of current in excess of 11,000,000 amperes per second. At this rate of rise in a large 650-volt (d-c) rectifier installation, the anode-breaker interrupting duty is equivalent to that of the first phase to clear a 130,000-kva fault in a three-phase 1,400-volt a-c system.

A short-cut method of estimating telephone-influence factor of power systems with rectifier load

In the planning of rectifier installations it is often desired to study the effect of the rectifier on co-ordination with communication systems. The telephone-influence factor <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> (TIF) is used in such studies as an index to the effect of distortion of the voltage and current-wave shapes on the inductive influence. Both voltage and current TIF are involved, because there are two types of induction: 1. Electric induction which depends upon the power-circuit voltage. 2. Magnetic induction which depends upon the current.

A Short-Cut Method of Estimating Telephone-Influence Factor of Power Systems With Rectifier Load

In the planning of rectifier installations it is often desired to study the effect of the rectifier on co-ordination with communication systems. The telephone-influence factor1 (TIF) is used in such studies as an index to the effect of distortion of the voltage and current-wave shapes on the inductive influence. Both voltage and current TIF are involved, because there are two types of induction: 1. Electric induction which depends upon the power-circuit voltage. 2. Magnetic induction which depends upon the current.

Harmonics and Load Balance of Multiphase Rectifiers Considerations in the Selection of the Number of Rectifier Phases

This paper analyzes the operating characteristics of multiphase power rectifiers from the standpoint of harmonics, load balance, and their interrelation, and their effects on the apparatus and circuits to which they may be connected. These factors are considered in connection with selection of the number of rectifier phases, which varies from six (four for very small sizes) to combinations of six-phase units to form a much larger number, such as 36, 72, or even 108 phases. More specifically, the problems of harmonics, load balance, and number of phases are considered from the standpoint of the effects on 1. Apparatus, particularly turbine generators and capacitors. 2. The wave-shape distortion on circuits that may be important in inductive co-ordination. 3. The possibility of resonance being encountered in the supply system to amplify one or more of the rectifier harmonics. These problems have increased greatly because of the great number and large size of rectifier installations made in connection with the war.

A Fast Circuit Breaker

DURING the past few years the rapid expansion of mercury-arc rectifier installations at 600 volts d-c, both as to the total kilowatts installed and the relatively large number of units operated in parallel, has emphasized the importance of switchgear in providing suitable rectifier operation. In the event of a backfire, the rates of current rise through a rectifier and its transformer windings lie, in general, between three million and six million amperes per second. With large installations, such as shown in Figure 1 where 60 units of 5,000 amperes each are operated in parallel, the ceiling value of these currents is far above a figure which could be tolerated both from the standpoint of continuity of operation and safety to equipment.

A fast circuit breaker

DURING the past few years the rapid expansion of mercury-arc rectifier installations at 600 volts d-c, both as to the total kilowatts installed and the relatively large number of units operated in parallel, has emphasized the importance of switchgear in providing suitable rectifier operation. In the event of a backfire, the rates of current rise through a rectifier and its transformer windings lie, in general, between three million and six million amperes per second. With large installations, such as shown in Figure 1 where 60 units of 5,000 amperes each are operated in parallel, the ceiling value of these currents is far above a figure which could be tolerated both from the standpoint of continuity of operation and safety to equipment.

Alcoa rectifier installation

IN 1938, 15 mercury arc rectifier units, with a total capacity of 82,500 kw, were placed in service by the Aluminum Company of America to supply d-c power for the electrolytic production of aluminum. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> In the plant at Alcoa, Tenn., ten of these units were installed to supply two 45,000 ampere, 600 volt, d-c circuits. In the plant at Massena, N. Y., five units were installed to supply one such circuit. These installations are noteworthy as they marked the first application of power rectifiers in this country for the electrolytic production of metal. At that time the Alcoa installation was the largest concentration of rectifiers in the country, with the highest kilowatt capacity, installed in a single station and operating on a common bus. Since 1938, one unit was added to each station in space reserved for it. At Alcoa twelve additional units were installed in a second station; six of these were placed in service in May 1940, and six in January 1941. This paper will describe the Alcoa rectifier installations. The Massena station is practically identical with the first Alcoa installation except for the number of units.

Alcoa Rectifier Installation

IN 1938, 15 mercury arc rectifier units, with a total capacity of 82,500 kw, were placed in service by the Aluminum Company of America to supply d-c power for the electrolytic production of aluminum.1 In the plant at Alcoa, Tenn., ten of these units were installed to supply two 45,000 ampere, 600 volt, d-c circuits. In the plant at Massena, N. Y., five units were installed to supply one such circuit. These installations are noteworthy as they marked the first application of power rectifiers in this country for the electrolytic production of metal. At that time the Alcoa installation was the largest concentration of rectifiers in the country, with the highest kilowatt capacity, installed in a single station and operating on a common bus. Since 1938, one unit was added to each station in space reserved for it. At Alcoa twelve additional units were installed in a second station; six of these were placed in service in May 1940, and six in January 1941. This paper will describe the Alcoa rectifier installations. The Massena station is practically identical with the first Alcoa installation except for the number of units.

Recent progress in power rectifiers and their applications

The paper gives a general survey of the present stage of development of power rectifiers. Recent innovations in the design of rectifier types are described, and some of the limitations arediscussed.The subject matter mainly concerns rectifiers of the mercury-arc type, including water-cooled rectifiers, glass-bulb rectifiers, pumpless air-cooled steel-tank rectifiers, and igniter types. Thesevarious rectifiers represent a voltage range from 200 volts to 50 kV (d. c), and currents up to about 10 000 amperes. Reference is also made to some of the leading non-vacuum rectifiers, such as jet-wave rectifiers, gas-cooled arc types, and electrolytic and mechanical types. Most of these are still in course of development, and an indication of the progress achieved is given. The more direct methods of controlling the output of the mercury-arc rectifiers by means of control grids are mentioned, and in this connection voltage regulation, inversion, and arc suppression, are discussed.General features of rectifier equipment are considered, together with some aspects of rectifier auxiliaries. The scope and performance of rectifier installations are also indicated, special reference being made to railway electrification, highvoltage working, and the applications of grid control.Finally, some suggestion of the possible trend of future developments is given.

New Trends in Mercury Arc Rectifier Developments

Research investigations conducted by engineers as well as physicists during the last few years have resulted in notable improvements in the mercury arc rectifier, in particular with reference to backfire protection and voltage regulation as well as improved manufacturing methods. These improvements made it possible to build rectifiers of very large current capacities as well as for very high voltages. The basic principle of rectification is briefly reviewed in order to explain the results obtained with the aid of these improvements. Methods of testing rectifiers have also been improved on and new ones developed. Standard parts are now used for different rectifiers up to the largest capacities. An account is given of notable recent rectifier installations for city subway service, for a portable street-railway substation, radio transmission, electrolytic zinc refining, and for Edison systems.

Abridgment of new trends in mercury arc rectifier developments

Research investigations conducted by engineers as well as physicists during the last few years have resulted in notable improvements in the mercury arc rectifier, in particular with reference to backfire protection and voltage regulation as well as improved manufacturing methods. These improvements have made it possible to build rectifiers of very large current capacities as well as for very high voltages. In order to explain the results obtained with the aid of these improvements the basic principle of rectification is briefly reviewed. Methods of testing rectifiers have also been improved upon and new ones developed. Standard parts are now used for different rectifiers up to the largest capacities. An account is given of notable recent rectifier installations for city subway service, for a portable street-railway substation, radio transmission, electrolytic zinc refining, and for Edison systems.

Mercury arc power rectifiers: Their applications and characteristics

Steel-enclosed mercury arc rectifiers, due to their advantages over rotary converters in efficiency, ease and reliability of operation, and ability to produce high d-c. voltages, are gradually replacing other forms of converters in all fields of application. There are at present 600,000 kw. of rectifier installations, distributed over different parts of the world. Statistical data are given showing the growth of installed rectifier capacity since 1911, the distribution of rectifiers over various fields of application, and their increasing use at higher voltages for railways. The high efficiency and reliability of rectifiers at high voltages will undoubtedly influence the selection of systems and voltages for main-line electrification. Comparative operating figures are given for rectifiers and motor-generator sets at 3000 volts d-c. Several types of Brown Boveri rectifiers and their load curves are shown. Due to the fact that the d-c. voltage of a rectifier consists of portions of sine waves, the voltage wave is somewhat undulated. The magnitude of the undulations depends on the number of phases and varies with the load. The effect of the undulations in the voltage wave on the shape of the current wave for various types of loads is discussed, and oscillograms of the voltage and current waves of a rectifier feeding a railway load under various conditions are shown. The effects of the undulations on different kinds of load — batteries, lighting, and power circuits — and on communication circuits paralleling the d-c. feeders are discussed briefly.

Mercury Arc Power Rectifiers Their Applications and Characteristics

Steel-enclosed mercury arc rectifiers, due to their advantages over rotary converters in efficiency, ease and reliability of operation, and ability to produce high d-c. voltages, are gradually replacing other forms of converters in all fields of application. There are at present 600,000 kw. of rectifier installations, distributed over different parts of the world. Statistical data are given showing the growth of installed rectifier capacity since 1911, the distribution of rectifiers over various fields of application, and their increasing use at higher voltages for railways. The high efficiency and reliability of rectifiers at high voltages will undoubtedly influence the selection of systems and voltages for main-line electrification. Comparative operating figures are given for rectifiers and motor-generator sets at 3000 volts d-c. Several types of Brown Boveri rectifiers and their load curves are shown. Due to the fact that the d-c. voltage of a rectifier consists of portions of sine waves, the voltage wave is some-what undulated. The magnitude of the undulations depends on the number of phases and varies with the load. The effect of the undulations in the voltage wave on the shape of the current wave for various types of loads is discussed, and oscillograms of the voltage and current waves of a rectifier feeding a railway load under various conditions are shown. The effects of the undulations on different kinds of load-batteries, lighting, and power circuits-and on communication circuits paralleling the d-c. feeders are discussed briefly.