A
vacuum circuit breaker can be differentiated from other circuit
breakers on the basis of its arc quenching technique. In this type,
the interruption of current flowing through arc takes place in
vacuum. This technology is widely used for applications working on
medium voltage. The vacuum circuit breakers are also suitable for
high voltage applications, however they are not commercially viable
yet. The vacuum circuit breaker consist of a vacuum interrupter. This
chamber is used for the basic operations of circuit breaker such as
opening and closing of contacts carrying electric current and arc
quenching. The vacuum interrupter is made by symmetrically arranging
ceramic insulators in a steel arc chamber. The hermetically tight
vacuum chamber present in vacuum circuit breaker eliminates any
external impacts on the device. Thus the properties of the vacuum
interrupter remain constant throughout the life cycle, giving it a
clear edge over the other types of interrupters.
The
most common application of vacuum interrupters is in the utility
sector. The energy efficiency norms have created an upsurge in the
innovation of technologies that reduce energy loses in power
generation and transmission. Innovation in recent years has given
rise to interrupters being fabricated without the use of sulfur
hexafluoride gas, which was previously considered essential. Mounting
concerns over carbon emissions and the need to improve
energy-efficiency, has led manufacturers to seek materials which are
energy-efficient for use in interrupter components.Classification of
the vacuum circuit breaker’s market is mainly done on the basis of
application that the interrupters are being used for. Some of the
major applications of interrupters are in circuit breakers, load
break switches, reclosers, contactors, tap changers and railway
circuit breakers. Also, depending on the power flow, interrupters may
be used for low, medium or high voltage power lines.
The
vacuum interrupters’ market is driven by some major micro and macro
factors that affect the demand and supply of the technology. One of
the major driver for this market is increase in population. This
surge in population has created high demand for electricity in
domestic, commercial as well as industrial markets. The construction
of new infrastructure as well modernization of old electric systems
in buildings has aided the demand for vacuum interrupters. Another
driver for this market presently, is the gradual shift of the
interrupter market from gas insulation interrupters (mainly using
sulfur hexafluoride as an insulator) to gas-free insulators, due to
regulations that inhibit the release of greenhouse gases into the
atmosphere. This has prompted the users/utility companies to replace
the older versions with the new ones. Certain interrupters also need
to be retired as they wear out over the years, which drive up the
sales for new ones.
The
major advantage of interrupters is that itreduces the power wastage
and curb the cost arising out of the energy loss during transmission.
However, the cost of the equipment is a major drawback for the vacuum
interrupter’s market. The major decision makers for the purchase of
interrupters are vendors, electric contractors, and distributors. The
high cost and lack of awareness may affect the decision on purchasing
of vacuum interrupter. The contractors or owners may prefer to
install low cost interrupters to reduce their upfront cost thereby
ignoring the efficiency advantage. In addition to this, vacuum
interrupters are rarely among the stock items. In most cases, the
manufacturers prefer making custom made interrupter depending upon
the project and geographical area.
Some
of the major companies involved in the manufacturing of vacuum
interrupters are General Electric, Kirloskar Electric Company Ltd.,
Chengdu Xuguang Electronics Co., Ltd., Crompton Greaves Ltd.,
Meidensha Corporation, Mitsubishi Electric Corporation, Siemens AG,
Toshiba Corporation, Wuhan Feite Electric Co., Ltd., ABB, AREVA, and
Eaton Corp.
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