Adaptation of the Simplex Algorithm to Modeling of Cold Load Pickup of a Large Secondary Network Distribution System

This paper describes a mathematical approach to the determination of the electrical load composition of a secondary network during cold-load re-energization. It is intended to answer two questions: What fraction of the normal steady-state demand must be restored at the time of re-energization in the most pessimistic case? What is the composition of this worse case restoration load?

The answers were obtained by making use of the Simplex Algorithm, a mathematical, but physically based, optimization procedure. The input data consisted of a customer survey of connected-load; maximum demand for this customer sample; experiencebased power requirement limits as a function of the time-of-day.

For comparison with the mathematically-based results, on-site visits were made to representative commercial enterprises. The results were used to construct, independently, a second cold-load restoration model. The two models were surprisingly close.