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.