MODULE 1

Question 1

is a natural electrical discharge that occurs during a thunderstorms when electrically charged in the atmosphere equalize

Answer 1

lightning

Question 2

are rooted in redirecting the immense energy of lightning strikes away from vulnerable structures, mitigating the risk of damage, fire or injury

Answer 2

principles of lightning protection

Question 3

focus on dissipating and diverting lightning’s electrical energy to minimize its impact on structures

Answer 3

passive protection measures

Question 4

employ advanced technology to detect, intercept, and counteract lightning strikes in real-time

Answer 4

active protection systems

Question 5

active protection system includes

Answer 5

early warning sensors
lightning detection networks
lightning suppression devices

Question 6

an electric discharge between cloud and earth, between clouds or between the charge centers of the same cloud

Answer 6

lightning

Question 7

starts from the cloud towards the earth and carries charge with it (will not reach the earth)

Answer 7

leader streamer or pilot streamer

Question 8

shoots up from the earth to the cloud

Answer 8

return streamer

Question 9

negative charge and positive charge

Answer 9

downward leader and return streamer

Question 10

lightning discharge may have a currents in the range of

Answer 10

10 KA to 90KA

Question 11

2 types of lightning strike

Answer 11

1.direct stroke
2.indirect stroke

Question 12

the lightning discharge is directly from the cloud to the subject equipment

Answer 12

direct stroke

Question 13

2 types of direct stroke

Answer 13

1.stroke A - tall objects
2.stroke B - ignores the height

Question 14

the lightning discharge from the cloud to the subject equipment

Answer 14

stroke A

Question 15

lightning discharge occurs on the overhead line as a result of stroke A between the clouds

Answer 15

stroke B

Question 16

result from the electrostatically induced charges on the conductors due to the presence of charge clouds

Answer 16

indirect stroke

Question 17

may cause serious damage to the expensive equipment in the power system

Answer 17

lightning surges

Question 18

the most commonly used devices for protection against lightning surges

Answer 18

1. earthing screen
   2.overhead ground wires
   3.lightning arresters or surge diverters
   4.surge absorber

Question 19

it consists of a network of copper conductors mounted all over the equipment in the sub-station or power station

Answer 19

earthing screen

Question 20

the most effective method of providing protection to transmission lines against direct lightning strokes

Answer 20

overhead ground wires

Question 21

protection against travelling waves

Answer 21

lightning arrester or surge diverters

Question 22

a protective device, which conducts the high voltage surges on the power system to the ground

Answer 22

lightning arrester of surge diverters

Question 23

it is a very simple line type of diverter and consists of two 1.5 cm rods which are bent at tight angles with a gap in between

Answer 23

rod gap arrester

Question 24

it consists of two horn shaped metal rods A and B separated by a small air gap

Answer 24

horn gap arrester

Question 25

in this type of arrester, two electrode spheres id taken and they both kept to near other by few distance

Answer 25

sphere gap arrester

Question 26

consist of a series of metallic (alloy of Zn) cylinders insulated from one another and separated by small intervals of air gaps

Answer 26

multi gap arrester

Question 27

also called "protector tube" commonly used on system operating up to 33KV

Answer 27

expulsion type lightning arrester

Question 28

it incorporate non-linear resistors and are extensively used on systems operating at high voltages

Answer 28

valve type lightning arrester

Question 29

Varios parts of valve type arrester, consist of 2 assemblies

Answer 29

Series spark gap non-linear resistor discs

Question 30

designed to have a low voltage impulse ratio, even less than one and to extinguish the arc. also known as lightning diverters or lightning rods

Answer 30

impulse protective gap (IPG) arrester

Question 31

operates using a thin film of aluminum hydroxide deposited on aluminum plates immersed in electrolyte. used in the conjunction with an impulse gap

Answer 31

electrolyte arrester

Question 32

a device used to protect electrical systems from high voltage surges, such as those that can be caused by lightning.

Answer 32

thyrite lightning arrester

Question 33

type of voltage arrestor that consists of stack of flat discs made of a porous material, such as porcelain, that are separated by thin mica rings

Answer 33

auto valve arrester

Question 34

a type of voltage arrester that uses certain dry chemicals that change their electrical conductivity upon the application of heat

Answer 34

oxide film arrester

Question 35

a type of voltage arrester that is commonly used in modern power system. it consists of a stack of series-connected metal discs made up of zinc oxide which has a highly non-linear resistance

Answer 35

metal oxide lightning arrester

Question 36

a protective device, which reduces the steepness of wave front of a surge by absorbing surge energy

Answer 36

surge absorber

Question 37

connected between the line and earth, can act as surge absorber. it protects transformer winding

Answer 37

condenser or capacitor surge absorber

Question 38

consist of a parallel combination of choke and resistance connected with the line

Answer 38

inductor or resistance surge absorber

Question 39

consist of an air cored inductor connected in series with the line

Answer 39

ferranti surge absorber