Computational Implementation of On-Line Loadflow

This paper describes a straightforward building method of initializing internal and external network system bus voltage and power injection operating levels for subsequent steady-state system security evaluation of planned and unplanned network contingency outages. Outages are of the line, tie-line, generator, or load loss type. The program can handle the opening of bus tie or jumper connections and the isolation of a bus or string of buses from the main part of the network. The routine´s main advantage is the automatic redistribution and makeup of tie-line P (MW) and Q (Mvar) flows from the external network. This algorithm has been implemented on the Iowa Illinois Gas and Electric Company (IIG&E) real-time control system; it is now under test and evaluation, and preliminary results are most favorable.