S5: Fault Analysis
48 EEE8044: Fundamentals
Section 5
Unbalanced Three Phase Fault Analysis
Introduction
代写留学生论文When considering unbalanced or unsymmetrical fault conditions like those shown in Fig.
5.1, it is no longer possible to use a simple per-phase equivalent circuit representation,since the same conditions do not apply to all three-phases of the power system. Instead, aspecial method for dealing with unbalanced networks is used known as the method ofsymmetrical components.
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(a) Line-to-earth
(c) Line-to-Line (d) Two lines-to-earth
(b) Line-to-earth
including earth fault resistance
Fig. 5.1 Unsymmetrical fault conditions
In this section, the method of symmetrical components will be introduced and then appliedto the analysis of circuit conditions during three different unbalanced fault conditions,namely a line-to-earth fault, a line-to-line fault and a double line-to-earth fault.
S5: Fault Analysis
49 EEE8044: Fundamentals
Learning Outcomes
On completion of this section you will be able to