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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
PDDC SEMESTER VIII- EXAMINATION SUMMER 2017
Subject Code: X80904 Date: 03/05/2017
Subject Name: Advance Power System II
Time: 10.30AM to 01.00PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Write a short note on Indian scenario of power systems and Electricity act, 2003. How it changed Electricity market?
07

Explain the causes and consequences of deregulated industrial load.
07
Q.2

Explain various applications of state estimations in a power system.
07

What is power system state estimation? Discuss Weighted Least Square Estimation (WLSE) method with usual notations for power system state estimation.
07
OR

Explain 2 (chi-square) technique for bad data detection for power system state estimation.
07
Q.3

What are the factors that affect voltage stability?
07

Give detail classification of voltage stability.
07
OR
Q.3

What is power system security? Explain with the help of an example.
07

Explain system state classification with relevant figures clearly showing the security levels and transition between different security levels.
07
Q.4

Why reactive compensation is required. Explain different methods of reactive compensation.
07

For a transmission line connected between two buses, derive the expression of voltage regulation and also establish from the phasor diagram and the equations that the Q and V have a strong coupling.
07
OR
Q.4

Explain load forecasting methodology with estimation of average and trend terms.
07

Derive the expression of critical voltage and angle at receiving end at voltage stability limit.
07
Q.5

Discuss voltage regulation in a transmission system and its relation with reactive power with the help of necessary phasor diagram and expressions.
07

A lossless three-phase 50 Hz transmission line has an inductive reactance of 0.8 Ω/km while capacitive admittance is 70 μS/km. If the system voltage at the sending is 220 kV (line-to-line) and the line length is 150 km, find electrical line length of the line surge impedance receiving end voltage at no-load with sending end voltage as reference the sending end current at no-load reactive power at the sending end at no-load surge impedance loading
07
OR
Q.5

State different methods for heavily loaded and voltage stressed power systems to enhance voltage stability. Very briefly discuss one of them.
07

What is voltage collapse? State different changes in power system contributing to the voltage collapse.
07