Power System Analysis

CHAPTER 6

Short-Circuit Analysis—1 (Symmetrical Fault Analysis

6.1 Introduction

Power system equipments are required to work under unpredictable conditions, such as with a live conductor touching the ground (the short circuit problem) or a lightning striking the conductors (the over voltage problem). Under faulty conditions of the system healthy phase voltages may rise beyond the rated value, the faulty phase current may increase abnormally or both these anomalies may occur concurrently. These are undesirable effects that may lead to damage of costly equipment due to the break down of insulation. A short circuit occurs when two points at different potentials are connected either with zero resistance (a dead short circuit) or with a substance ...