For Academic Session 2013

(EE-455)

Electrical Power System Protection

Pre-Labs

Prepared by: Dr. Memon

Department of Electrical Engineering

N.E.D. University of Engineering & Technology, Karachi

Pre – Lab: 01

Q No. 01: Describe working of DC shunt motor with its equivalent circuit ?

Q No. 02: Describe working of synchronous generator by its equivalent circuit?

Q. No. 03: What is the importance of phase sequence and why it should be detected?

Q. No. 04: If one phase among three gets failed what is the effect on machines?

Q. No. 05: Why load unbalancing should be avoided?

Q. No. 06: Explain Negative sequence components and in what conditions they are produced

in power systems ?

Q No. 7: What are the effects of negative sequence components in power systems ?

Pre – Lab: 02

Max. / Min. Voltage relay in 3ϕ Network

Q. No. 01: What is the role of reactive power in the power network?

Q. No. 02: How inductive load affect Voltage level in the circuit?

Q. No. 03: Can power factor improvement affect Voltage level?

Q. No. 04: What are the other methods to improve Voltage levels?

Q No. 05: Define Voltage Stability and its relationship to lack of reactive power in

System ?

Pre – Lab: 03

Study and apply a Max. / Min. frequency relay.

Q. No. 01: How frequency of Generator can be changed?

Q. No. 02: How inductance of power system can be changed?

Q. No. 03: Which relay can be used for load shedding?

Q No. 4: What is the effect of AGC (Automatic Generation Control) in power system?

Q No. 5: Define Angle stability and its relationship with the change of frequency in the

system?

Pre – Lab: 04 + 05

Application of over current relay

Q. No. 01: Describe temporary overload condition?

Q. No. 02: Describe continuous overload conditions?

Q. No. 03: Describe a technique to differentiate between temporary overload and continuous

overload?

Q. No. 04: How to differentiate between overload and short circuit conditions?

Q. No. 05: What do we mean by on-delay timer?

Q. No. 06: What do we mean by off delay timer?

Pre – Lab. No. 06

Remote Signaling

Q. No. 01: Give some important level sensing examples in power systems?

Q. No. 02: Give some examples of other industries except power systems where level

sensing is very important / critical?

Pre – Lab. No. 07

Current Transformer

Q. No. 01: Describe the importance of CT error?

Q. No. 02: Explain CT error calculation by giving an example?

Pre – Lab. No. 08

Voltage Transformer

Q. No. 01: Describe importance of VT error?

Q. No. 02: Describe VT error calculation by giving an example?