This part of IEC 60143 applies both to capacitor units and capacitor banks intended to be used connected in series with an a.c. transmission or distribution line or circuit forming part of an a.c. power system having a frequency of 15 Hz to 60 Hz. The primary focus of the document is on transmission application. The series capacitor units and banks are usually intended for high voltage power systems. This standard is applicable to the complete voltage range. This standard does not apply to capacitors of the self-healing metallized dielectric type. The following capacitors, even if connected in series with a circuit, are excluded from this standard: - capacitors for inductive heat-generating plants (IEC 60110-1); - capacitors for motor applications and the like (IEC 60252-1); - capacitors to be used in power electronics circuits (IEC 61071); - capacitors for discharge lamps (IEC 61048 and IEC 61049). Standard type of accessories such as insulators, switches, instrument transformers, external fuses, etc., should comply with the pertinent IEC standard.