52216-mt----advanced Power System Protection

NR

Code No: 52216/MT

M.Tech. – II Semester Regular Examinations, September, 2008 ADVANCED POWER SYSTEM PROTECTION (Common to Electrical Power Systems/ Electrical Power Engineering/ Power Engineering & Energy Systems) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.a) b)

Explain what are primary and back up protections. Explain various methods of providing back-up protection. Explain the basic difference between a CT used for instrumentation and a CT used for protection.

2.a) b)

What are the various types of over current relays? Explain the operating principle and constructional features of a directional relay.

3.a)

Discuss how an elliptical characteristic is realised using static comparators. Why is an elliptical characteristic used only for backup protection? Discuss how swivelling characteristic is realised using a phase comparator.

b) 4.

Explain the term pilot with reference to power line protection. What are the different types of pilots which are presently employed? Discuss their fields of application.

5.

How can R and X of the line as seen by the relay can be calculated using an algorithm based on the discrete Fourier transform.

6.

How the A/D converter ADC 0809 can be used to read any instantaneous value of the ac voltage?

7.

How can a quadrilateral distance relay be realised using a microprocessor?

8.

Explain the generalized program flow chart for digital distance relays using 8086 microprocessor. $$$