Reference no: EM133058233

Fault Analysis - Power Systems Analysis

The tasks in the recorded instruction are slightly different from those in this lab sheet, the techniques, and the necessary navigation in PWS are identical.

Question 1. Power World Simulator Lab5_case1 (available in the course web page within Moodle, under the Lab folder) models a small power system with all data on a 1000MVA base. Using PWS, apply three phase faults at buses 2 and 7. For each fault, determine:
(a) the fault current currents and give comparative analysis of the values.
(b) The contribution to the fault from each generator to the fault current at the two buses and give comparative analysis of the values.
(In PWS follow: Tools → Fault Analysis, then click on "Single Fault". Check recording.)

Question 2. Apply a three-phase fault midway between Buses 1 & 2. Generate a table of the voltages (magnitude and angle) at the different buses and explain how the values relate to the fault location.
(This can be done by selecting the "In-Line Fault" option within the "Fault Analysis" window.)

Question 3. One technique for limiting fault current is to place reactance in series with the generators or lines immediately after transformer buses. Such reactance can be modelled in PWS by increasing the value of the generator's positive sequence internal impedance. How much per-unit reactance must be added to G2 to limit its maximum fault current to 1.5 per unit when a three-phase fault is applied at:
(a) Bus 6 and
(b) Bus 2.
Explain why one of the two faults (a & b above) required bigger reactance value to maintain the maximum fault current.

Question 4. Using PWS Lab5_case2,
(a) Compare and contrast the fault levels at bus two for three-phase, single line to ground, line to line and line to line to ground faults.
(b) plot the variation in the phase "a", "b" and "c" voltage magnitudes as the fault reactance is varied from 0 to 2.0 per unit in 0.2 per-unit steps for the following fault types: three-phase, a single line- to-ground, line to line and line to line to ground faults. Discuss your observation.

(The fault impedance is specified on the Fault Options page of the Fault Analysis page - the resistance value is left at zero by default.)

Critical analysis of the results of the different faults (1-4 above) should enable you to draw some relevant conclusions about the different types of faults.

Attachment:- Fault analysis.rar