This paper describes a graphical easy-to-use power system simulation softwa
re. The software is specially designed to meet the requirements of saving t
ime and effort in its use. Visualization, automation of some manual procedu
res and solution of special problems in subtransmission networks has been r
ealized. An efficient network diagram editor is introduced. The combined us
e of the network diagram and the automated substation diagrams facilitates
network operation state setting and interpretation of results. Some practic
al techniques have been adopted to improve the convergence of load flow and
var optimization computations. Furthermore, the automatic network topology
analysis function has contributed a lot to error finding in the built netw
ork database and the input data of network status. It has been successfully
used in two Chinese electric utilities. (C) 2000 Elsevier Science Ltd. All
rights reserved.