Lightning Lightning

Surge ProtectionSurge Protection

And And Earthing Arrangment Earthing Arrangment

WHY WHY Lightening And Surge ProtectionLightening And Surge Protection

• Introduction of electronic based equipments-IPS,DAC ,SSI,AFTC,OFC etc.

• These and are low voltage device and depends on electric supply hence vulnerable to transient over voltages on power lines

• Further with compact design and reduction of interspacing between components the probabilty has increased.

Types of surgesTypes of surges• Lightening Energy: Releasing mega-joules of

energy

• Power Line Surges: Electrical machinery, appliances and power company’s operating equipment. air conditioners, generators, transformers and pumps etc.

• Indirect Strikes: Galvanic, inductive and capacitive couplings between sensitive quipment and the lightening effected

HOW TO PROTECTHOW TO PROTECT

•Filter and clampFilter and clamp the transient pulses at the the transient pulses at the point of point of power entrypower entry to the installation to the installation

• Reducing over voltage by stagesReducing over voltage by stages to a to a harmless level before it reach the terminal device harmless level before it reach the terminal device and cause damage.and cause damage.

TYPICAL REQUIREMENT OF SURGE FILTERTYPICAL REQUIREMENT OF SURGE FILTER

• It should be able to carry full load current in series with the incoming mains power supply.

• It should be able to cater for the levels of energy experienced in lightning discharges

• It should be able to cater multiple lightning events which may occur within milliseconds of the initial discharge.

• It should be able to limit the energy levels between phase & neutral and neutral & ground respectively.

PROTECTION LEVELSPROTECTION LEVELS

• CLASS “A” PROTECTION –to protect against direct strike

• CLASS “B” PROTECTION

• CLASS “C” PROTECTION

• CLASS “D” PROTECTION

CLASS B PROTECTIONCLASS B PROTECTION

•First stage of protection at mains distribution First stage of protection at mains distribution panelpanel

•Based on self restoring spark gap Based on self restoring spark gap technology technology

•

•Handle lightning current pulses of 10/350 Handle lightning current pulses of 10/350 ss

•Provided between both Phase to neutral and Provided between both Phase to neutral and Neutral To Earth Neutral To Earth

CLASS C PROTECTIONCLASS C PROTECTION

•Based on fast responsive MOVBased on fast responsive MOV

•Provided between Phase and Neutral Provided between Phase and Neutral

CLASS D PROTECTIONCLASS D PROTECTION

All external data/signaling (AC/DC) lines All external data/signaling (AC/DC) lines connected to electronic equipment at either connected to electronic equipment at either end should be protected by using Class “D” end should be protected by using Class “D” device which consists of a combination of device which consists of a combination of MOVs and GD tubeMOVs and GD tube

EARTHINGEARTHING

Requirement for functioning of lightning Requirement for functioning of lightning protection is a correctly installed protection is a correctly installed equipotential bonding system supplemented equipotential bonding system supplemented with arresterswith arresters

Conventional methodConventional method

• G.I pipe buried in the ground prepared by layers using charcoal and salt

• Connecting Earth Rod to Equipment by GI wire

• Connections made by using ordinary nut bolts

DRAWBACKSDRAWBACKS

• Periodical pouring of Water • Corrosion of GI pipe due to salts. • Consumption of Salt as it is soluble. • This type of earth gives earth resistance of upto

10 Ohm • Less dissipation of fault current with increase in

resistance• Recurring cost of maint.

Latest technique of EarthingLatest technique of Earthing

• Use of Copper bonded steel rod with high tensile strength.(250micron cu,15mmdia)

-These rods are long life as they don,t corrode and offer less resistance

• USE of Earth enhancing compound (GEM)in place of salt and charcoal .

- This compound when in contact with the earth produces a highly conductive non corrosive gel which interacts with the earth homogenously with all types of soil. This helps the earthing electrode to retain moisture.Higher doses may be necessary for optimum results in high resistance soil or rocky areas.

- Low resistivity is maintained due to this material

•

• Use of Copper tapes/Cadmium bronze wires/Copper tapes for interconnection

- This offer better conductivity

• Making connection by Exothermic welding

-This ensures proper connection

.

InstallationInstallation

Earth Pit

- To be prepared by digging hole of 8’

- Insert Earth Rod by Augur upto 11’

- Fill up GEM

RING EARTH BARRING EARTH BAR

• All Rooms shall be provided with Copper Tape of 25X6x300 with holes

• The tape shall be connected to the wall by insulators of 6kv at 60mm ht

• The relay racks /equipment to be connected to Above Copper Tape by 6SQMM Cu wire using stainless steal Nut BOLTS

• All SUCH REBs shall be connected my Cu Tape of size 25X3

INTER CONNECTIONSINTER CONNECTIONS

• The Ground Rod Shall Be provided with 25x6X300 strip exothermically welded to it.

• The REB shall be connected to Earth Rod by laying Cadmium Bronze wire (3/16”)which shall be exothermically welded to copper tape provided on Ground Rod

• The above wire shall be laid in trench of 12”depth width of 1’ filled with GEM

• In case earth resistance is not achieved with single earth more earth pits shall be made with distance not more than 2L

• Earth pits shall be interconnected in same way as that for connection between Earth Pit and REB

A Provision of maintenance free Single earth        

  Schedule A – Supply portion Unit Rate QTY AMT

1 Supply of basic earthing kit – 1 set consisting of a. Earth electrodes of copper clad steel alloy of ¾ inch dia & copper thickness of min of 10 mit ,10ft long or 2 no. 6 ft long b. thread less compressed type coupler of copper clad steel alloy with copper thickness of min 10 mit -01if 6 ft rod is supplied c. RDSO approved earth enhancing compound in 10 kg pack -1 no d. Copper tape of 25 mmx3mmx150mm to terminate on earth electrode.-1N0.

Set 8000 1 8000

2 Copper tape of 25 mmx6mmx150mm to act as REB- NO 1170 4 4680

3 Supply of insulated cadmium bronze cable of 3/16” to RDSO spec.RDSO/SPN/178/2003 to connect equipotential bus bar in Relay room and master earth electrode in pair for redundancy.

MTR 225 40 9000

4 Supply of insulated copper cable of 6 sqmm mtr 25 58 1450

  Total A       23130

  Schedule B – Labour portion        

1 Installation of unit earth consisting of a.digging the earth to the required depth b. Insertion of 1/2 nos electrodes c. Joining electrodes using coupler(if 6ft rod) d. Filling of earth enhancing compound Provision of exothermic weld connection on copper tape of 25mmx3mmx150mm to the earth electrode(weld material tools & fixtures required for the weld to be arranged by the contractor) -1 no.provision of exothermic weld connections one to connect the cadmium bronze cable to the copper tape welded to the earth electrode and another to the copper tape to be fixed inside the equipment /relay rack/apparatus room(fixtures for mounting the copper tape inside the relay room, weld materials and tools & fixtures for the weld shall be arranged by the contractor.g. electrode termination in a concrete sink and routing the cadmium cable to bus bar in equipment room Various REB and other appratus in room to be joined by 6sq mm cu wire

NO 1 6000 6000

  TOTAL A+B       29130

B Provision of maintenance free Ring earth (3 earth pit)        

  Schedule A – Supply portion Unit Rate QTY AMT

1 Supply of basic earthing kit – 1 set consisting of a. Earth electrodes of copper clad steel alloy of ¾ inch dia & copper thickness of min of 10 mit ,10ft long or 2 no. 6 ft long b. thread less compressed type coupler of copper clad steel alloy with copper thickness of min 10 mit -01if 6 ft rod is supplied c. RDSO approved earth enhancing compound in 10 kg pack -1 no d. Copper tape of 25 mmx3mmx150mm to terminate on earth electrode.-1N0.

Set 8000 3 24000

2 Copper tape of 25 mmx6mmx150mm to act as REB- NO 1170 4 4680

3 Supply of insulated cadmium bronze cable of 3/16” to RDSO spec.RDSO/SPN/178/2003 to connect equipotential bus bar in Relay room and master earth electrode in pair for redundancy.

MTR 225 40 9000

4 Supply of Copper tape of 25 mmx3mmmm to connect two earth pits MTR 30 540 16200

5 RDSO approved earth enhancing compound in 10 kg pack - NO 3 2500 7500

6 Supply of insulated copper cable of 6 sqmm mtr 25 58 1450

  Total A       62830

  Schedule B – Labour portion        

  Installation of unit earth(3no) consisting of a.digging the earth to the required depth b. Insertion of 1/2 nos electrodes c. Joining electrodes using coupler(if 6ft rod) d. Filling of earth enhancing compound ,Connecting adjacent earth pits by copper tape of 25x3 by making requisite exothermic connectionsProvision of exothermic weld connection on copper tape of 25mmx3mmx150mm to the earth electrode(weld material tools & fixtures required for the weld to be arranged by the contractor) -2 no.provision of exothermic weld connections one to connect the cadmium bronze cable to the copper tape welded to the earth electrode and another to the copper tape to be fixed inside the equipment /relay rack/apparatus room(fixtures for mounting the copper tape inside the relay room, weld materials and tools & fixtures for the weld shall be arranged by the contractor.g. electrode termination in a concrete sink and routing the cadmium cable to bus bar in equipment roomVarious REB and other appratus in room to be joined by 6sq mm cu wire

NO 1 10000 10000

          72830

THANK YOUTHANK YOU