Inrush Restraint

When closing onto typical loads, there may be an initial surge in current caused by phenomena such as:

• Transformer magnetizing currents

• Motor starting currents

• Start-up current of incandescent and arc lights

These surges are transient and referred to as Inrush Current. Depending on the active protection settings at the time, this inrush current may cause overcurrent protection to operate unnecessarily.

The purpose of Inrush Restraint helps to prevent the ACR from tripping due to inrush current.

The PowerLogic ADVC Controller supports two modes of operation for Inrush Restraint, Zero Detect and SOHIR. This section describes the Zero Detect mode. SOHIR, or SOHIR is described in the next section.