Switchgear Testing Research Articles

Industrial Medium Voltage Cable and Switchgear Maintenance and Testing, Part I

Increasing costs of unscheduled production downtime in manufacturing industries, coupled with high costs for repair of electrical distribution equipment, dictate that planned electrical maintenance and testing play an important role in the industrial manufacturing process. Subject matter important to performing a planned electrical maintenance and testing program of medium voltage industrial cable and switchgear will be reviewed.

High-voltage switchgear

The paper begins by summarising the way in which the design of high-voltage (above 1 kV) switchgear has been affected by changes in the constitution of the manufacturing industry, both nationally and internationally, by advances in the knowledge and theory of arcs and circuit breaker operation, and by changing tendencies in service conditions that influence specification, rating and testing requirements. It describes the greatly increased application of circuit breakers and totally enclosed switchgear using sulphur hexafluoride as an arc-quenching medium and insulant, the commercial breakthrough of the vacuum interrupter and the universal acceptance and use of synthetic methods of testing circuit breakers. It then deals with ratings and service requirements, research and the theory of arcs and circuit breakers, standardisation and switchgear testing. It concludes by illustrating, with examples, the current trends in the design of apparatus, especially circuit breakers, and the layout and equipment of switchboards and substations.

A high current mains frequency synchronous switch

A mains frequency synchronous switch, using a thyristor and its associated trigger-pulse generator, is described which is capable of switching peak currents of over 7000 A for a single half cycle at 50 Hz. The absence of mechanical switching simplifies the operation and installation compared with mechanically operated synchronous switches. The device has been used for investigating arc discharges, but might be used for any application requiring a high current pulse for several milliseconds duration including short circuit and switchgear testing.

High-voltage switchgear. A review of progress

After describing the development of the ratings of switchgear for voltages above 100kV during the last few years and indicating the current trends, the paper considers the more important special conditions for which modern switchgear has to be designed. A brief account is given of the present state of the theory of circuit breaking and of the research now being conducted, together with a review of the switchgear testing methods and stations now in operation.The principles of the more recent developments in the design of circuit breakers, isolators, switches, instrument transformers, surge diverters, fuses, insulators and the layout of substations are illustrated by examples from British and foreign practice. An indication of possible developments in totally enclosed switchgear for high voltages and in the switching of high-voltage direct current is given.

A Short-Circuit Testing Laboratory in an Educational Institution

The establishment of a short-circuit testing laboratory in an educational institution is quite an innovation, particularly in an area of the world where the conventional high power switchgear testing laboratory is non-existent. Affording postgraduate training and research in arc phenomena and the scientific development of arc extinction devices, this excellent facility will provide the country with switchgear engineers and contribute to the design and local manufacture of modem switchgear. Although minimal in rating, the design of the laboratory, particularly the generator, controls, and instrumentation presented a number of unique problems, since it was most desirable to minimize the loss of short-circuit power in the test circuit. These special features and characteristics of the principal apparatus are described in this paper.

Expansion of a high-power switchgear testing laboratory

Expansion of a high-power switchgear testing laboratory

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.

Metal enclosed switchgear testing and design

Metal enclosed switchgear testing and design

1,100,000-kva short-circuit transformer in the new high-capacity switchgear testing laboratory [includes discussion

This paper describes the design and construction of a particular testing transformer, custom-built to meet requirements imposed by its use in high-voltage short-circuit testing of circuit breakers, fuses, disconnect switches, and so forth, at the new high-capacity switchgear testing laboratory' of the General Electric Company. While some of the problems usually encountered in power transformer designs were reduced to insignificance by specific requirements, others were magnified to the extent that normal construction was out of the question. Consequently, the design is quite special and includes a number of unusual features which are described herein.

Transformers for new Switchgear testing laboratory

FGR HIGH-VOLTAGE short-circuit testing of circuit breakers, fuses, disconnect switches, and so forth, at the new high-capacity Switchgear Testing Laboratory of the General Electric Company, Philadelphia, Pa., two 1,100,000-kva short-circuit transformers were installed.

New high-capacity switchgear testing laboratory

This new high-capacity switchgear development laboratory is considered a necessary adjunct to the company's engineering and manufacturing facilities. It will be used primarily for circuit interrupter development, but it can perform many types of tests.

New High-Capacity Switchgear Testing Laboratory [includes discussion

This new high-capacity switchgear development laboratory is considered a necessary adjunct to the company's engineering and manufacturing facilities. It will be used primarily for circuit interrupter development, but it can perform many types of tests.

Discussion on “Some factors affecting the design of alternators for switchgear testing” before the North-Eastern Centre, at Newcastle, 23rd November, 1942

Discussion on “Some factors affecting the design of alternators for switchgear testing” before the North-Eastern Centre, at Newcastle, 23rd November, 1942

Some factors affecting the design of alternators for switchgear testing

The greatly increased prospective fault MVA at many switching stations, due to the rapid growth of interconnections on many systems during the last 15 years, has necessitated the design of circuit-breakers of larger capacity. This in turn has made desirable improved facilities for technical investigations and for proving the rating of the breakers.The paper discusses the mechanical and electrical factors which affect the design of alternators supplying power for switchgear testing. A review is made of several methods of increasing the output of such alternators, and the merits of each are critically examined.

Some factors affecting the design of alternators for switchgear testing

Some factors affecting the design of alternators for switchgear testing

Discussion on “Apparatus used for high-power switchgear testing” before the North Midland Centre, 19th January, 1937

Discussion on “Apparatus used for high-power switchgear testing” before the North Midland Centre, 19th January, 1937

Apparatus used for high-power switchgear testing

The paper deals with the equipment and construction of modern high-power testing laboratory capable of testing circuit breakers of ratings up to 1 500 MVA at voltages up to 132 kV.General details of the power circuit are given, including the generator, super-excitation system, load and power factor control, step-up and step-down transformers, and switchgear.The metering and instrument equipment is also described, particulars being given of both low- and high-frequency oscillographs and their associated components.

Testing Switchgear

THE safety of every electricity supply system depends on its switchgear always being ready to operate. The main switches (circuit-breakers) must always be capable of making and breaking the current, and still remain fit for use. The development of the grid system has proved the necessity of being able to ‘clear’ a fault even when fed by enormous currents. For many years, the firms now constituting Associated Electrical Industries have had extensive experience of short-circuit tests made with generators having capacities up to 80,000 kilovolt amperes. In an article in Electrical Industries of October 14, a description is given of a testing station having a generator capable of giving 2,500,000 k.v.a. on short circuit. In order to meet the demand for more tests and for tests at higher powers, the companies interested combined to form a separate company known as the Switchgear Testing Co., Ltd., which now owns and operates the plant on their behalf. The testing station is situated at Trafford Park, Manchester. Ample space had to be provided to ensure personal safety, and, when ‘testing to destruction’, to avoid damage to property by explosion and fire. The station has three testing areas; two are covered over and used for testing up to 33 kv., and one is an open area, testing up to the grid voltage of 132 kv. The station has a complete equipment for measuring and recording phenomena. Its electromagnetic oscillograph has sixteen elements and is probably the only oscillograph of this kind in the world. It is satisfactory to know that these companies have taken a leading part in conjunction with other firms both in Great Britain and abroad in producing a standard specification for procedure in testing circuit breakers which is recognized internationally.