IEEE C57.16-2025

Revision Standard - Active.

Recommendations are given for reactors intended for series connection, in both transmission and distribution systems, to control power flow under steady-state conditions and/or limit fault current under short-circuit conditions.

Dry-type air-core reactors covered by this standard are self-cooled by natural air convection.

Other reactors, including:

• filter reactors,
• shunt capacitor reactors (used with shunt capacitor banks),
• discharge current limiting reactors (used with series capacitor banks), and
• ac-side converter reactors

are also covered.

This standard applies to series-connected dry-type air-core single-phase and three-phase outdoor or indoor reactors of distribution and transmission voltage class that are connected in the power system to control power flow under steady-state conditions and/or limit fault current under short-circuit conditions.

Dry-type air-core reactors covered by this standard are self-cooled by natural air convection. Normative Annex A, Annex B, and Annex D provide the requirements for filter reactors, shunt capacitor reactors/transient limiting inductors (TLIs), used with shunt capacitor banks, and discharge current limiting reactors, used with series capacitor banks, respectively.

Normative Annex E provides the requirements for these reactors when supplied in enclosures. Information on series-connected, alternating current (ac)-side converter reactors without a significant level of dc current is provided in the informative Annex H. Additional application guidance for series reactors is provided in informative Annex C, Annex F, and Annex G.

This standard does not apply to devices such as the following:

• a) Shunt reactors (see IEEE Std C57.21™)
• b) Arc-suppression coils (see IEEE Std C57.32™ [B46])
• c) Neutral grounding devices (see IEEE Std C57.32 [B46])
• d) Line resonant reactors
• e) High-voltage direct current (HVDC) smoothing reactors (IEEE Std 1277™ [B33])
• f) Forced cooled reactors
• g) Line traps and radio interference (RI) filter reactors (IEEE Std C93.3™)
• h) HVDC converter reactors with a significant level of dc current (IEEE Std 1277 [B33])

The purpose of this standard is to define the requirements and test code for series-connected dry-type air-core reactors, including filter reactors, shunt capacitor reactors, and discharge current limiting reactors.