Load, Voltage Drop, and Reliability Indices

The computational layer behind reliable service: load factor and demand, why diversity lets a 25 kVA transformer serve ten homes, feeder thermal limits, voltage drop down a feeder against ANSI C84.1 Range A, the regulator/capacitor/CVR toolkit, and computing SAIDI, SAIFI, CAIDI, and MAIFI from a real outage log including major-event-day exclusions.

  1. 1 Load, Demand, Peak, and Load Factor The load hierarchy from instantaneous load to peak demand, and load factor as the ratio that tells you how hard a feeder's installed capacity is working. Finish the lesson above to unlock this. Locked
  2. 2 Diversity, Coincidence & Demand Factors Why ten 6 kVA homes do not need a 60 kVA transformer, and the three ratios (demand, diversity, coincidence) that explain the gap. Locked
  3. 3 Feeder Loading and Thermal Limits How to test whether a new load fits on a feeder: add its coincident contribution against the conductor's thermal ampacity, not its raw nameplate. Locked
  4. 4 Voltage Drop Down a Feeder Why voltage falls the whole way down a loaded feeder, where the legal ANSI C84.1 floor sits, and why the utility's 5% design target is a separate number. Locked
  5. 5 Holding Voltage in Spec: Regulators, Caps, CVR Four tools move a feeder's voltage in three different directions: regulators and cap banks raise it to correct a sag, CVR lowers it on purpose inside Range A, and doing nothing accepts the drop. Locked
  6. 6 Computing SAIDI, SAIFI, CAIDI & MAIFI Turn a raw outage log into IEEE 1366 numbers: compute SAIDI in minutes, SAIFI, the derived CAIDI, and a separate MAIFI for momentaries. Locked
  7. 7 Major Event Days: Why Storm Days Are Excluded Why utilities pull storm days out of routine SAIDI and SAIFI, and how IEEE 1366's statistical 2.5-beta method sets a Major Event Day threshold from a utility's own history. Locked