IEEE C57.21-2021

This standard applies to all oil-immersed or dry-type, single-phase or three-phase, outdoor or indoor shunt reactors rated over 500 kVA. This standard also applies to thyristor-controlled shunt reactors used in static var compensators (SVCs). This standard does not apply to other devices such as the following: a) Shunt reactors, 500 kVA and smaller b) Current-limiting reactors (see IEEE Std C57.16(TM)-2011) c) Arc-suppression coils d) Neutral-grounding devices (see IEEE Std 32(TM)-1972) e) Saturable reactors f) Line-resonant reactors g) Filter reactors