High Power Laboratory Research Articles

Expansion of a high-power switchgear testing laboratory

Expansion of a high-power switchgear testing laboratory

Switckgear and Control Features of Enlarged High-Power Testing Laboratory

Higher capacity testing facilities are being put into service at the Westinghouse Electric Corporation high-power testing laboratories at East Pittsburgh. This paper deals primarily with some of the switchgear and control features of the increased capacity facility.

An Enlarged High-Power Switchgear Testing Laboratory

A high-power switchgear testing laboratory is a necessary tool for the development of new circuit breakers which meet the requirements of modern electrical systems. This paper describes additions to an American laboratory which increase its power, voltage, and effectiveness. The additions include a generator, transformers, capacitors, a test cell, switchgear, and instrumentation.

High-Power Laboratory Tests on High-Capacity High-Voltage Oil Circuit Breakers

Although for many years many high-capacity outdoor oeb's (oil circuit breakers) have given satisfactory service with only field tests to establish their interrupting rating, it is acknowledged that supplementiing laboratory tests are required to assess fully their ultimate capabilities. Laboratory tests can be made of any severity and the limitations of a given breaker design can be observed. This paper covers a test program utilizing the maximuin short-circuit output of one of the largest testing laboratories, to observe the performance of high-capacity interrupters for ocb's, with voltage ratings of 69, 115, 138, 161, and 230 kv. Previous field tests had given indications that the designs, in general, were satisfactory up to the limits tested. These additional tests were made for the purpose of finding out more about their interrtlpting characteristics and their ultimate limits. Two single-pole test units were used: one for the 69-kv tests, and one for the 115-to 230-kv tests. In recent years, there has been general agreement on the impracticability of separate interrupter designs for the many possible interrupting and voltage ratings. Therefore, in addition to the standardization of a small number of ratings by the industry, manufacturers have carried standardization a step further by utilizing fewer different interrupter designs. This point is applicable to the last-mentioned group of ratings where a single interrupter design was considered approxpriate for voltages of 115, 138, 161, and 230 kv.

The 115-kv, 1 million kva gas-filled breaker

A 115-KV CIRCUIT BREAKER of moderate interrupting capacity designed to meet some special and definite applications has long been deemed desirable on the transmission system of the Gulf Power Company. Consequently, when the gas-filled (sulfur-hexa-fluoride) Type 1150-SF-1000 power circuit breaker rated for 115-kv, 1 million kva service became available, this utility company agreed to purchase three in order to obtain service experience and to permit staged field tests for comparison with test results obtained in the High Power Laboratory.

A new milestone in circuit-breaker interrupting capacity 25 million kva at 330 kv

With the tremendous loads considered for 330-kv lines, circuit breakers functioning at this voltage are needed with 2,000 amperes continuous current capacity and an interrupting rating of 25 million kva. The description of a breaker's new design, permitting the full interrupting rating to be demonstrated with present test facilities, and its assembly demonstrate how designers and engineers have solved the problems presented by the power companies. FIVE YEARS ago development progress was reported on circuit breakers rated 10 million kva at 230 kv. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,2</sup> Since that time breakers of this rating have been built and installed on 138-kv, 161-kv, and 230-kv systems. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3–5</sup> Instead of this rating proving to be a ceiling, an interrupting capacity of 15 million kva has been considered at 161 kv, 230 kv, and 330 kv. Now the heavy loads being projected for 330-kv lines in this country, particularly the tremendous concentration of electric power at the new Atomic Energy Commission plant near Portsmouth, Ohio, have brought a demand for 330-kv breakers with 2,000 amperes continuous current capacity and the unprecedented interrupting rating of 25 million kva. This article describes one way in which this challenge has been met, and in particular how the high arc-rupturing capacity has made necessary a radically new design which will permit the full interrupting rating to be demonstrated adequately with available High Power Laboratory testing facilities.

A New Milestone in Circuit-Breaker Interrupting Capacity - 25,000,000 Kva at 330 Kv [includes discussion

With the tremendous loads considered for 330-kv lines, circuit breakers functioning at this voltage are needed with 2,000 amperes continuous current capacity and an interrupting rating of 25 million kva. The description of a breaker's new design, permitting the full interrupting rating to be demonstrated with present test facilities, and its assembly demonstrate how designers and engineers have solved the problems presented by the power companies. FIVE YEARS ago development progress was reported on circuit breakers rated 10 million kva at 230 kv.1,2 Since that time breakers of this rating have been built and installed on 138-kv, 161-kv, and 230-kv systems.3–5 Instead of this rating proving to be a ceiling, an interrupting capacity of 15 million kva has been considered at 161 kv, 230 kv, and 330 kv. Now the heavy loads being projected for 330-kv lines in this country, particularly the tremendous concentration of electric power at the new Atomic Energy Commission plant near Portsmouth, Ohio, have brought a demand for 330-kv breakers with 2,000 amperes continuous current capacity and the unprecedented interrupting rating of 25 million kva. This article describes one way in which this challenge has been met, and in particular how the high arc-rupturing capacity has made necessary a radically new design which will permit the full interrupting rating to be demonstrated adequately with available High Power Laboratory testing facilities.

65,000-kvar high-power laboratory capacitor bank for variety of switching tests

This new capacitor bank, which can be operated up to 65,000 kvar, has widened considerably the range of testing possible in the high-power laboratory. In this way it furnishes facilities in line with the electrical industry's rapid growth.

Flexible High-Power Laboratory Capacitor Bank for Variety of Switching Tests to 65,000 Kilovars [includes discussion

Flexible High-Power Laboratory Capacitor Bank for Variety of Switching Tests to 65,000 Kilovars [includes discussion

Verifying circuit-breaker interrupting capacity

TWELVE high-speed 230-kv oil circuit breakers rated 10,000,000 kva interrupting capacity are installed now in transmission-line and bus-tie positions of the left switchyard at the Grand Coulee Power Plant. The development of these important pieces of protective equipment has required extensive short-circuit testing both in a manufacturer's high-power laboratory and at Grand Coulee Dam. This article covers the final stages of that development and describes in particular the field tests which were made in August 1950 in order to verify the circuit-breaker interrupting capacity rating of 10,000,000 kva and also to determine any possible margin above this figure.

New Design Oil Circuit Breakers for 7,500,000-Kva 230-Kv Service

As a logical step in the trend toward achieving a minimum oil content but still retaining the advantages of the time-proved dead-tank construction a new 230- kv circuit breaker built around a novel design of tank has been developed. The extra volume of oil which contributes nothing to the insulation nor to the efficiency of the circuit breaker in interrupting performance has been eliminated and the required amount of oil reduced to the point where simplified methods of oil handling and maintenance procedures are possible. Design tests on the circuit breaker prove its adequacy in meeting design standards and extensive High Power Laboratory tests reveal a superior performance in interrupting fault and line-charging currents. The quantity of oil used and the design of the contacts is such as to permit a number of fault interruptions without maintenance operation.

High-Voltage Oil Circuit Breakers for 5,000,000- to 10,100,000-Kva Interrupting Capacity

The paper describes some of the special design features for steel-tank oil circuit breakers rated 5,000,000 kva at 138 kv, 161 kv, and 230 kv, and rated 7,500,000 or 10,000,000 kva at 230 kv. The method of verifying these interrupting capacities both in the manufacturers' high-power laboratory and by field tests on a customer's property is outlined, with special consideration given to the problems of switching line-charging currents and of interrupting high power repeatedly, under both standard duty and rapid reclosing duty cycles.

Circuit Breaker Modernization and Faster Fault Clearing on Single-Phase Electrified Railroad

The circuit breakers designed in 1913 for sectionalizing the 11/22 kv 3-wire trolley and feeder circuits on the New Haven Railroad electrification had become inadequate by 1936 because of limited interrupting capacity to clear line faults fast enough to insure system stability and reliability. Although these were never designed to handle the entire fault interrupting duty, space and weight limitations in the switching stations and supporting structures ruled out their replacement with modern circuit breakers of conventional design adequate for faster fault clearing. The application of modern interrupters to the original circuit breakers, together with the redesign of tanks, operating mechanism and supporting frames (with spring supports), produced a circuit breaker of approximately the same over-all dimensions and weight which by high-power laboratory tests proved to be adequate to interrupt the entire fault current (instantaneous rms symmetrical) as determined by a-c network calculator studies of the system. These studies were also the basis of application of instantaneous overcurrent relays for fault clearing by the line circuit breakers, of which there are over 500, making this system one of the largest installations with this type of relay protection. An analysis of the network calculator studies, the tests of the redesigned circuit breaker, and the operating results with their application are here reported.

The next step in interrupting capacity — 5,000,000 kva

Serious consideration is being given to large power-system interconnections which could develop short circuits at certain locations in excess of 3,500,000 kva. High-voltage oil-circuit-breaker capabilities for such heavy duty are reviewed in this paper, the fundamental design requirements outlined, and results of high-power laboratory tests presented which demonstrate that interrupting capacity ratings as high as 5,000,000 kva are feasible. Laboratory test methods for demonstrating these extremely high arc rupturing ratings are evaluated. The importance of verifying high-speed reclosing performance with high-power tests is emphasised, and on the basis of data already obtained, standard reclosing time intervals considerably less than 20 cycles are foreseen.

The next step in interrupting capacity-5,000,000 Kva

Serious consideration is being given to large power-system interconnections which could develop short circuits at certain locations in excess of 3,500,000 kva. High-voltage oil-circuit-breaker capabilities for such heavy duty are reviewed in this paper, the fundamental design requirements outlined, and results of high-power laboratory tests presented which demonstrate that interrupting capacity ratings as high as 5,000,000 kva are feasible. Laboratory test methods for demonstrating these extremely high arc rupturing ratings are evaluated. The importance of verifying high-speed reclosing performance with high-power tests is emphasized, and on the basis of data already obtained, standard reclosing time intervals considerably less than 20 cycles are foreseen.

A Multiorifice Interrupter for High-Voltage Oil Circuit Breakers

High-voltage oil circuit breakers for high-speed operation generally use some form of multibreak contact arrangement. These breakers perform satisfactorily but lack the simplicity of the conventional slower-speed two-break construction. The development of an unusually effective multi-orifice oil-flow interrupting unit now makes it possible to reduce the required number of breaks to the point where even three-cycle 230-kv breakers appear practical with only two interrupting units per pole. High-power laboratory tests on low magnetizing and charging currents, as well as. short-circuit currents corresponding to interrupting ratings of 2,500,000 kva and above, have demonstrated the exceptional arc-extinguishing effectiveness and low arc-energy dissipation of this multiorifice interrupter for high-speed oil circuit breakers.

Transactions section: Preprint of corresponding pages from the current annual AIEE transactions volume: High-capacity circuit-breaker testing station

TEN years' experience with a high-power laboratory, giving approximately 1,100,000 three-phase initial symmetrical kilovolt-amperes on short circuit at the machine bus, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> has defined its usefulness and limitations and has resulted in an addition to its installed equipment. By taking advantage of assymmetry this capacity has been sufficient to demonstrate ratings up to 1,500,000 kva, and the increased testing capacity is required to demonstrate interrupting ratings of 2,500,000 kva.