A feeder leaves the substation at 122 V on a 120 V base. Under peak load, the last house on a long lateral reads 112 V, below the ANSI C84.1 Range A service floor of 114 V. The line crew’s truck carries four things that can touch that number. Two of them raise it, one lowers it on purpose, and one does nothing. Before reading on, guess which is which.
A 32-step voltage regulator raises or bucks voltage in discrete steps to counter the drop. It does not measure the far end of the line. Instead it uses line-drop compensation, an R-and-X estimate of the drop out to a chosen regulation point, and holds target voltage there. A shunt capacitor bank works differently: it supplies VARs right at its location, which raises voltage and unloads the reactive current the feeder would otherwise carry from the substation. Both tools exist to lift a sagging feeder back inside the 114 to 126 V window.
Conservation Voltage Reduction is different in kind from the other two. CVR deliberately lowers voltage toward the low end of Range A, not to fix a violation, but to cut energy consumption, since many loads draw less power at lower voltage. Its hard limit is the same 114 V floor: it trims voltage down but must never cross it.
Put all four on one axis and the choice stops feeling like a grab bag. Regulator and cap bank raise, CVR lowers, and accepting the drop holds where it lands. As a buyer or operator, the question is never “which box fixes voltage” but which direction the feeder actually needs to move and which tool moves it that way. Order a cap bank where you needed a regulator, or run CVR on a circuit already scraping the floor, and you have spent money making the problem worse.
SAIDI and SAIFI targets drive capital planning, and capital planning drives what gets ordered and when. The Feeder tracks the reliability investment and regulatory signals behind those orders, free, every week.