A Dynamic Power System Model With Graded Precision for Fast Extraction of Pertinent Load Flow Information

In many situations of power system restoration or emergency control load flow, often dynamic load flow, results are needed at a time scale which makes regular load flow computations impractical. In this paper a low order dynamic model is introduced which retains fully detailed and precise representation of the critical components (such as strong backbone lines like EHV or weak tie lines) where the interest is focused and reduces the detail of representation of other parts of the system gradually with their distance from the spotlighted sections where details are needed. The result is a low order and hence very fast computation with not only detailed but also quite precise results for those parts of the system which are critical. This approach is very flexible, it can be used to compute tie line load and frequency swings on an interconnection of areas or static loads on the tie lines of such a system affecting third parties in a power trading situation. It can be used to compute precisely and fast the EHV system loads or any combinations of such elements. The operator is quite free to choose what should be represented in precise detail.