(A) Porcelain or toughened glass
(C) Silica
(D) Cement
(D) Clay
Answer: (A) Porcelain or toughened glass
Explanation:
Insulators: Insulators are the materials which offer very high resistance to the flow of current
Insulators used for high-voltage power transmission are made from glass, porcelain or composite polymer materials
Porcelain insulators are made from clay, quartz or alumina and feldspar, and are covered with a smooth glaze to shed water
The surface of the insulator should be glazed enough so that water should not be traced on it and make current very negligible
More MCQS
1. Under over excitation synchronous phase modifier works as
2. The neutral of the power system may be connected to earth
3. The time to open the circuit breaker contact is called as
4. A 100 Ah capacity battery should deliver a current of 10 A for approximately _____ hrs.
5. For 400KV line, The Spacing Between phase conductor is around
6. Shunt capacitors in a sub-station
7. An alternator is said to be over excited when it is operating at
8. In case of transformer Buchholz relay is used to protect from
9. Series capacitors are used to
10. Disadvantage of low power factor is
11. The colour of neutral three core flexible cable is
12. The location of ground faults in underground cables can be found by
13. Fault location in an HV cable is done by
15. Which of the following is not a valid advantage of bundle conductor?
16. Star-star power transformer is protected by current transformer having
17. The surge resistance of cables is
18. Skin effect is only noticeable at _______ frequencies.
19. When transmission voltage is increased, the line losses are
20. Var compensators are used to
21. High voltage transmission lines use