Neutral grounding reactors are used for low impedance grounding of high voltage systems. They limit the line to ground fault current under system fault conditions.Typically, these reactors are installed adjacent to the power transformer and are connected between the neutral bushing and ground.
Under balanced operating conditions, there is essentially no continuous current flowing through the neutral grounding reactor. Therefore, the rated current of this reactor is considered to be the thermal short time current under fault conditions.
The duration of the short time rating is time dependent, and is specified as 10 seconds or one minute. Other time durations may also be specified. The continuous current is calculated as a function of the rated current in accordance with IEEE standard 32, unless otherwise specified.
For example: An application requires a neutral current limiting reactor for a 10,000 amp thermal fault current rating for a 10 second rating. The continuous current would normally be designed as 3% of the 10,000 amp rating, or 300 amps. However, if the calculated continuous current is available, this will take precedence.
Neutral Grounding Reactor in a Transclosure Housing & Neutral Grounding Reactor, 600 amp, 15 kV
Neutral Current Limiting Reactor Specification
A1 Scope: These specifications cover neutral grounding reactors for a voltage rating of ____ volts at 60 hertz (or 50 hertz).
- A1.1 The reactor shall be air core type ____ henries, ____ ohms, ____ amps, and shall be designed in accordance with the latest applicable standards of the C-57 series of ANSI/IEEE.
- A1.2 The reactor shall be wound with aluminum conductor and have aluminum bus bar ____ "x ____ @ with NEMA pads one for incoming and outgoing connections.
- A1.3 The reactors shall be wound on a fiberglass re-enforced polyester tube.
- A1.4 The reactor shall be sealed with a weather/water resistant fiberglass resin epoxy material to form a complete system.
- A1.5 The assembly then shall be dipped in a thermal setting resin and baked to cure.
- A1.6 The reactors shall be as manufactured by Gilbert Electrical Systems & Products catalog number A-44xxxxC.