Joseph Ong Aug 2005 Company Confidential 1 Earthing / Grounding IssuesReasons for Earthing and BondingDetect fault current and fast removal of poer source at fault!revent potential differences hich ma" cause electrocution or spar#s$inimise the effect of lightning stri#es!revent %uild&up of E'D$inimise the effect of electrical interferences$eet E(plosion&!roof apparatus safet" re)uirementsReference: MTL websiteJoseph Ong Aug 2005 Company Confidential 2 Earthing / Grounding Issues*round + earth resistance and resistivit" should %e measured hen,-nstalling ne ground s"stems and electrical e)uipment!eriodicall" testing of ground and lightning protection rods !rior to design of ground protection s"stemsJoseph Ong Aug 2005 Company Confidential . Earth Testing Methods /all of !otential 0 . and 1 !ole 2esting Resistivit" 'elective 2esting 'ta#eless 2estingJoseph Ong Aug 2005 Company Confidential 1 Earth Testing Methods (1)Fall of Potential Three and Four Pole TestingJoseph Ong Aug 2005 Company Confidential 5 Earth Testing Methods (1)Fall of Potential Three and Four Pole Testing

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E325m 25mIJoseph Ong Aug 2005 Company Confidential 4 Earth Testing Methods (1)Fall of Potential Creating the #"$ Cur%e The positioning of temporary ele&trode for the test isa &riti&al issue The distan&e 'et(een ele&trodes is dependant on the #pool of potential$ of the earth system under testD i s t a n c e ( m ) )istan&es of temporary ele&trode should 'e %ariedto plot %alues as an #"$ &ur%eJoseph Ong Aug 2005 Company Confidential 5 Earth Testing Methods (*)esisti%ity MeasurementFrom the indi&ated resistan&e %alue E+ the soil resisti%ity &al&ulates a&&ording to the e,uation -E . * / a /E E////// mean %alue of soil resisti%ity (/m)

E////// measured resistan&e ()a ////// pro'e distan&e (m)Joseph Ong Aug 2005 Company Confidential 6 Prin&iple- 0enner MethodPrin&iple- 0enner MethodMeasurement of spe&ifi& earth resistan&e Measurement of spe&ifi& earth resistan&e 2hemeasuringmethodaccordingto7ennerdeterminesthesoil resisti%itydo(ntoadepthofappro1/thedistan&e2a2'et(eent(o earth spi3es/B"increasing8a89deeperla"erscan%emeasuredandchec#edfor homogeneit":B"changing8a8severaltimes9aprofilecan%emeasured from hich a suita%le earth electrode can %e determined: Accordingtothedepthto%emeasured98a8isselected%eteen2mand .0 m: 2his procedure results in curves,Joseph Ong Aug 2005 Company Confidential ; Earth Testing Methods (*)Cur%e 1-As E decreases onl" deeper don9 a deep earth electrode is advisa%leCur%e *-As E decreases onl" don to point A9 an increase in the depth deeper than A does not improve the values:Cur%e 4-7ith increasing depth E is not decreasing, a strip conductor electrode is advisa%le:esisti%ity MeasurementJoseph Ong Aug 2005 Company Confidential 10 Earth Testing Methods (4)"ele&ti%e Measurement MethodJoseph Ong Aug 2005 Company Confidential 11 Earth Testing Methods (4)"ele&ti%e Measurement Method

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E325m 25mAIJoseph Ong Aug 2005 Company Confidential 12 Earth Testing Methods (4)!rinciple, 'elective earth measurements !rinciple, 'elective earth measurements5d%antage- )istin&t earth resistan&es (ithin meshed ground systems &an 'e measured (ithout dis&onne&tion/ 6nly &lamp &urrent Im is used for &al&ulation of E/Important- The minimum &lamp &urrent is 7/8m5 if not+ an error message is displayed/ )isplay . E4 99ImMeasured%oltageMeasured &urrent IMPro'e5u1iliaryearthele&trodeJoseph Ong Aug 2005 Company Confidential 1. Earth Testing Methods (4)"ele&ti%e Measurement Method on !igh Tension To(ersJoseph Ong Aug 2005 Company Confidential 11 Earth Testing Methods (4)Measurements on high tension to(ers Applica%le for nearl" all metal constructions< E(ample, 2oer ith four stands: Important- )o not mo%e the &urrent in:e&tion point (E) during test9 All stands are tested in se)uence ith the split core transformer:ring earthele&trodesplit &ore transformerJoseph Ong Aug 2005 Company Confidential 15 Earth Testing Methods (4)Joseph Ong Aug 2005 Company Confidential 14 Earth Testing Methods (;) )isplay. < / IE . EConne&tionto e,ui=potential'us 'arE,ui Potential 'us 'ar0ater pipeEarth ele&trode

E 7ater pipeIE 7ater pipe -sum = -E >-E 7ater pipePro'e = (")?voltage reference@5u1iliary earth = (!)?inAection of test current@5ppli&ation- Fun&tion 5ppli&ation- Fun&tion E E sele&ti%esele&ti%e6nly the &urrent from the &urrent &lamp is used for &al&ulation of E/The pre&ise %alue of E is on display9

Esum"5T GE6 ?+ "5T GE6 plusJoseph Ong Aug 2005 Company Confidential 15 Earth Testing Methods (;)"ta3eless Measurement MethodJoseph Ong Aug 2005 Company Confidential 16 Earth Testing Methods (;)"ta3eless Measurement MethodJoseph Ong Aug 2005 Company Confidential 1; Earth Testing Methods (;)"ta3eless Measurement MethodJoseph Ong Aug 2005 Company Confidential 20 Earth Testing Methods (;)5ssume that there are n resistan&es in parallel (e/g/ in meshed ground systems+ tele&om+ ele&tri& po(er distri'ution systems) earth &onne&tions are inter=&onne&ted/ Thus n@@1 is %alid/ n is negligi'le and the measuring loop resistan&e is mainly 1/ In this &ase the %alue on display of theIn this &ase the %alue on display of the ground loop tester is e1a&tly 1/ ground loop tester is e1a&tly 1/Current amplifierAoltage sour&eIIRx nU'ta#eless earth loop measurements 'ta#eless earth loop measurementsRx R1 R2 Rm-1 RmRxRx R1 R2 Rm-1 RmRx n. m earth resistan&es in parallel Joseph Ong Aug 2005 Company Confidential 21 Earth Testing Methods (;)!rinciple, 'ta#eless earth measurements !rinciple, 'ta#eless earth measurementsErder'la&3red /or all applications ith at least to earth electrodes:::e:g: high tension toers9 meshed grounding s"stems9telecom&ca%les ::::::'impl" put %oth clamps around conductor9 ca%le9 pipe etc:Blamps ith a large variet" of openings are availa%le:B 17&mEarth ele&trodeAdapter 0 for *EO C onl"Joseph Ong Aug 2005 Company Confidential 22 Earth Testing Methods (;)E1ample- "ta3eless earth measurementE1ample- "ta3eless earth measurement