This reports how many of the modules configured on this phase, out of the total in tsiPhaseNbModConfigured, are designated as redundant spares rather than modules whose capacity is counted in the phase's installed, non-redundant, power figures. It is the exact number subtracted from tsiPhaseNbModConfigured to determine the installed-power denominator used in tsiPhaseInstalledPowerRatioW and its VA counterpart, so an admin questioning why the installed and available power ratios differ for this phase would check this value to understand exactly how many modules of margin are being held back for redundancy. A phase configured with 5 modules where this value reads 1 means only 4 modules' worth of capacity counts toward the phase's non-redundant installed rating.