Todays modern utility systems are much more stable and robust than in previous years, however, a tradeoff often occurs when increased inrush currents cause problems when equipment is energized. This is especially prominent in outdoor distribution capacitor banks. These banks are becoming much more common as the need for voltage and VAR support grows and are typically installed at multiple points along a utility system. However, many times upon restoration of power after an outage, capacitors, vacuum switches, and fuses may be damaged due to the large high frequency inrush current characteristic of capacitor banks.
Elgin has a great solution for this problem. We manufacture high quality air core current limiting reactors. One of our premier products is the “pancake” reactor. Specifically designed for capacitor banks it is rated for 40 uh, and 160 amps. Compact and lightweight, these epoxy encapsulated reactors are a perfect fit for outdoor capacitor banks. They are easily installed either directly on the vacuum switches, or on bus or insulators. They serve to mitigate inrush or fault damage while reducing arc flash exposure. These reactors are typically applied from 480v up to 35kv. They are also a perfect solution to limit “back to back” inrush currents in capacitor banks with multiple stages. Once installed these units immediately limit inrush and fault current to a lower, more manageable level. This current limiting effect is achieved by the “inductive reactance“ of the reactor’s air core winding. This simple design has no moving parts, requires no maintenance and is easily installed either indoors or outdoors as desired.