Question’s on Chapter 1
Complete the following:-
a) The purpose of protection is to minimize the effects of
electrical power systems problems (Short circuits -
Abnormal conditions - Equipment failures)
b) During normal operation the protection system(clear/ leave )
the power system
c) During abnormal operation the protection system(trip/
alarm then trip/ leave ) the power system
d) During transient operation the protection system(trip/ alarm
then trip/ leave ) the power system
e) The main components used for protection are: Fuse –
Transducers - Relays – Circuit breakers – Communication
link – DC System
f) Relays monitor various parameters like (Voltage and
Current) and detect fault when happen and isolating these
components
g) C.B used to used to isolate the faulty circuits, they are
capable of carrying fault currents until the fault currents are
totally cleared
h) Voltage transformers and current transformers measure
(V,I) and are capable of providing accurate measurement
during fault conditions without failure
i) Communication link is used to ………… to or from other
relays or substation
j) Occurrence of the fault with in the overlapped region will
……………..
k) .Overlapping Zones around …………..
l) For No Overlapping Zones, a fault in between zone
boundaries may ……………………
m) Remote backup relays are completely ………. of the
relays transducers, batteries, and CBs of the protection
system they are backing up
n) locally backup , is, in the ………………………
o) The main reasons for main protection failure:-1-……….., 2-
………., 3-…………………………, 4- ………………..
p) For back up protection these points must be taken into
account:- 1-……….., 2-………., 3-…………………4-……
q) Backup protection Methods are:- 1-……….., 2-………., 3-
…………………4-……
r)
1. Why the power system needs the protection system?
2. List basic requirements of protection system?
3. State the main performance requirements for any protection
system?
4. Explain with sketch basic arrangement of a protection scheme?
5. Mention the roles for any protection system?
6. Sketch and explain the main three parts of relay circuit
connections?
7. Why an electric power system is divided into several zones of
protection? Sketch any power system and divided it into several
zones?
8. Explain the main roles for making zones for power system?
9. Why the zones of protection should overlap? Discriminate with
sketch between closed or open zone?
10. Explain the following:
11. State the roles should be satisfied when dividing the power
system into zones?
12. . Explain primary, duplication and back up protection?
13. How make back up protection for lower voltage systems?
How make back up protection for high voltage systems?
14. Stat the main reasons for main protection failure?
15. List main points that must be taken into account when making
back up protection? State the backup protection methods?
16. Compare between two kinds of backup relaying?
17. List the protection roles?
