chapter  13
Load Tap Changers
Pages 32

Today, both the IEEE term ‘‘load tap changer (LTC)’’ and the IEC term ‘‘on-load tap-changer (OLTC)’’

are in the terminology of international standards, but the term ‘‘load tap changer (LTC)’’ is used

primarily in this chapter. Load tap changers are one of the indispensable components for the regulation

of power transformers used in electrical energy networks and industrial application. This contribution

explains the technological developments of resistor-type LTCs as well as of reactor-type LTCs. The

general switching principles for LTCs are discussed and applications of LTCs are introduced. Today’s

design concepts of LTCs are described including the new generation of vacuum-type LTCs. The vacuum

switching technology-used in LTCs-is the ‘‘state-of-the-art’’ design at the present time and for the

foreseeable future. Examples of LTC designs and the associated switching principles show the variety of

the use of vacuum interrupters.