E equal o faults currents with 120 displacement is

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Unformatted text preview: ents with 120 displacement) is called a symmetrical fault. The most common example of symmetrical fault is when all the three conductors of a 3-phase line are brought together simultaneously into a short-circuit condition. The method of calculating fault currents for symmetrical faults is discussed in chapter 17. (ii) Unsymmetrical faults. Those faults which give rise to unsymmetrical currents (i.e. unequal line currents with unequal displacement) are called unsymmetrical faults. The unsymmetrical faults may take one of the following forms : 395 Introduction to Switchgear (a) Single line-to-ground fault (b) Line-to-line fault (c) Double line-to-ground fault The great majority of faults on the power system are of unsymmetrical nature; the most common type being a short-circuit from one line to ground. The calculations of such fault currents are made by “symmetrical components” method. This is fully discussed in chapter 18. SELF - TEST 1. Fill in the blanks by inserting appropriate words/figures. (i) A fuse is a ......
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This note was uploaded on 11/12/2012 for the course MBA 101 taught by Professor Muhannad during the Spring '12 term at Bradford School of Business.

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