MEDICIONES PUESTA A TIERRA PRESENTACION FLUKE.pdf

7/23/2019 MEDICIONES PUESTA A TIERRA PRESENTACION FLUKE.pdf

1/65

Earth_testing_2006 Eric van Riet 1

Earth testing

Earth testingPractical

Earth Testing Techniques and

Measurement Instruments


2/65


Practical Earth Testing

Content

Principles

Test Methods Practical Measurement

Summary


3/65


What is ground?

A conducting connection, whether intentional oraccidental, between an electrical circuit or equipmentand the earth, or to some conducting body that serves in

place of earth*

Ground is a connection to Earth made eitherintentionally or accidentally

*NFPA 70-2000 (National Fire Protection Association)

Earth / Ground Basics


4/65


Why ground?

By dissipating stray energy from:

Electrical faults (fuses, breakers etc.)Lightning strikes

Radio FrequencyStatic discharges

To protect people and equipment



5/65


Estimate: at least 15% of power quality problems arerelated to grounding

Lightning strikes on equipment with poorly maintainedprotection systems destroy millions of dollars of equipmentand lost production every year

Using ground testing in a PDM protocol will help prevent

possible dangerous situations and loss of downtime(= money)

Why test? Catch the problem before it happens!

Real Examples


6/65


How do you connect to earth?

Cable or tape

Stake or rod

Earth material



7/65


Spheres of influence



8/65


Attention! Potential gradients!

Potential gradients aroundthe earth electrode canreduce the accuracy of

measurements!

The probe must always beplaced outside this area!Typical distance: >20m

Umeasure

Distance a

Ground Potential

Neutral ground, r eference

Umeasure



9/65


Types of Grounding Systems

Ground rod


Many different types available

Choice depends on localconditions and required

function

Simplest form is a single stake

Mostly used for: Lightning protection

Stand alone structures

Back-up for utility ground


10/65

Earth_testi ng_2006 Eric van Riet 10


Ground rod group


ground rod group

typically for lightning

protection on largerstructures or protectionaround potential hotspotssuch as substations.


11/65



Ground plate


For areas where there isrock (or other poorconducting material) fairlyclose to the surface groundplates are preferred as theyare more effective


12/65



Ground mesh


A ground mesh consists ofnetwork of bars connected

together, this system is oftenused at larger sites such aselectrical substations.


13/65



For the purposes ofthis presentation thegrounding system

will referred to asground electrode.



14/65


What are the available techniques?

Resistivity

Fall of Potential Three and Four Pole Testing Selective Testing

Stakeless Testing

Two pole method

Ground Testing Methods


15/65


Resistivity Measurement

The purpose of resistivity measurements is to quantify theeffectiveness of the earth where a grounding system will beinstalled.

Differing earth materials will affect the effectiveness of thegrounding system.

The capability of different earth materials to conduct current

can be quantified by the value E (resistivity in .m).

Resistivity measurements should be made prior to installing agrounding system, the values measured will have an effect onthe design of the grounding system.

Ground Testing Methods (1)


16/65


Resistivity values for different earth materials



17/65


Resistivity Measurement ( Wenner method)

Resistivity measurements are performed by using afour wire method.

Used to determinewhich KIND ofearthing should beused, so BEFOREplacing earth stakes



18/65



From the indicated resistance value RE, the soilresistivity is calculated according to the equation :

E = 2 . a . RE

E ...... mean value of soil resistivity (W.m)RE ...... measured resistance (W)

a ...... probe distance (m)



19/65


Curve 1: As E decreases onlydeeper down, a deep earthelectrode is advisable

Curve 2: As E decreases onlydown to point A, an increase inthe depth deeper than A doesnot improve the values.

Curve 3: With increasing depthE is not decreasing: a stripconductor electrode isadvisable.




20/65


Fall of Potential - Testing


The Fall of Potential method is the most commonlyused method of testing.

Three or four pole method, this refers to the number ofconnections made to the ground tester.

The forth pole of the connection is made if the wire toconnect to the system under test is particularly long

> 4 meters. The additional wire cancels out an error dueto the extended length of wire used.


21/65


Earth Testing Methods (1)

Fall of Potential 3 / 4 Pole Testing


The E terminal of theinstrument is connectedto the electrode under

test


22/65


Earth Testing Methods (1)Ground Testing Methods (2)

If the length of this wireis greater than 4 meterit is recommended thatan extra wire isconnected between theelectrode under testand the ES terminal toeliminate any errorintroduced due to thelength of the lead, thisis then known as the 4pole test



23/65



The test spike C2 isplaced in the groundsome distance fromelectrode under test(typically 50 meter)



24/65



The voltage spike P2 isplaced in the groundsome distance fromelectrode under test(typically 80 feet) .Once the stakes are inplace the test canproceed.


During the test theinstrument drives acurrent through the test

spike, through thesurrounding earth andreturns through theelectrode under test,the potential caused bythis current ismeasured using the P2spike.

From the current andvoltage measurementsmade it is possible tocalculate a value ofground resistance.


25/65



A number of readingsshould be taken withthe the P2 spike at

different distances, sayfrom 20 to 35 meters at3 meter intervals.



26/65



The distance of the P2 spike is varied to ensure that it ispositioned outside of the sphere influence of the electrodeunder test.

When the P2 spike is close to the electrode under test themeasured value appears to be lower and as it becomesinfluenced by the C2 spike the measured value rises.

The optimal point of measurement is outside of theinfluence of the electrode and the C2 spike.

Taking a series of measurements and plotting theseagainst distance produces the curve shown.




27/65



Fall of Potential Creating the S Curve

The optimum value is that indicated on the flat part ofthe curve



28/65



The 62% Rule

The 62% rule is a guide to how far away the P2 and C2stakes should be placed from the electrode under test.

The distances are nominally based on the depth of the

electrode.


Depth of Electrode

under Test (E)

Distance from E to

Potential Stake (P2)

Distance from E to

Current Stake (C2)

6 50 82

8 62 100

20 81 131

30 100 161


29/65



Distances for Electrode Arrays

The 62% rule is a guide to how far away the P2 and C2stakes should be placed from the electrode under test.

The distances are nominally based on the depth of the

electrode.


Widest Dimension

(Diagonal, diameter or

Straight-line) of Electrode

Array under Test (E)

Distance from E to

Potential Stake (P2)

Distance from E to

Current Stake (C2)

65 100 165

80 165 265

100 230 330

165 330 560

230 430 655


30/65


Selective Measurement Method


The selective methodis based on the fall ofpotential test

But: without the needto disconnect theground electrode undertest.

A current clamp is usedto isolate the testcurrent injected in to

the electrodes undertest.

Test CurrentTest CurrentTest CurrentTest Current


31/65




This applicationexample shows thebenefit of the selective

test in a typicalinstallation

Firstly the groundspikes are positioned

according to therequirements of thesystem under test.


32/65




Then individualelements of the systemcan be measured by

placing the currentclamparound the differentconnections to groundwithout the need of anydisconnection.


33/65


Selective Measurement Method - Advantages


Ground electrodes can be tested without powering downthe system they are protecting saving time and money

Testing can be carried out without disconnecting savestime, money and improves safety

Multiple electrodes can be tested quickly simply bymoving the current clamp to individual electrodes


34/65



The stakeless method eliminates the need for temporaryground stakes. This is useful in a wide range of situations.Examples include:

Inside buildings

Airports

Urban locations

Chemical and industrial plants

The stakeless method is not available on all ground testers.However, it comes standard on the Fluke 1623 and 1625 earthground testers.

The temporary ground stakes are replaced by two current clamps.The first clamp generates a voltage on the ground condutor, thesecond clamp measures the current flowing due to the generatedvoltage.


35/65



The Fluke 1623 and 1625testers are able to measureearth ground loopresistances for multigrounded systems using only

current clamps.

With this test method, twoclamps are placed aroundthe earth ground rod or

connecting cable and eachconnected to the tester.Earth ground stakes arentused at all.


36/65


The clamps are placed around theground conductor



37/65


Stakeless Measurement Equivalent Circuit



38/65



If there is only one path to ground, like at someresidential applications, the stakeless method will notprovide an acceptable value and the Fall of Potentialtest method must be used.

An abnormally high reading or an open circuit indicationon the instrument points to a poor connection betweentwo or more of the aforementioned critical components.

An abnormally low reading could indicate the instrumentis measuring a loop of bonding conductors.


39/65


Two Pole Method


Used where other methodsare not available.Uses nearby metal

structures as a temporaryspike.Metal water pipes aretypically used


40/65


Two Pole Method


Drawbacks:

The resistance of the metal

pipe should be significantlyless than the electrodeunder test.Metal pipes are beingreplaced with plastic.

Some metal pipes useplastic couplings.


41/65


Selecting a test method

Advantages Drawbacks

Fall-of-Potential

Widely accepted

When you see the characteristiccurve you know youve got a

good measurement.

You have to disconnect ground

The stakes may not be to drive

There may not be space around theground electrode to drive the stakes

Selective

Method

Dont have to disconnect

electrode Widely accepted

When you see the characteristiccurve you know youve got a

good measurement.

The stakes may not be easy to dr ive

There may not be space around theground

StakelessMethod

Convenience Assumes a low-impedance paral lelpath

Possible to get very low readings bymistakenly measuring on a hard-

wired loop

Two-poleMethod

Convenience Impossible to judge the integrity ofthe auxiliary electrode.

Cant be sure you are outside thearea of inf luence

Summary of Ground Electrode Test Methods


42/65


Prior to designing an grounding system:the ground material should be evaluated by resistivity

measurement before designing a ground systemInitial test on new ground systems:the real effectiveness of new ground systems should bemeasured before connection fall of potential test

Periodic tests on ground systems:ground systems should be checked periodically to ensurethey are not affected by changes in the ground orcorrosion selective or stakeless test

Ground Testing Applications

When and why ground test?


43/65


Testing prior to addition of major loads:prior to installation of sensitive equipment such as servers,

CT scanners, control systems, etc. fall of potential,selective or stakeless

Safety tests on major equipment and plante.g. ground tests on machines, elevators, conveyor belts,

transformers, substations, boards, motors stakeless and selective testing especially useful




44/65


All other tests for relevant ground connections e.g. lightningprotection, pipelines, tanks, gas stations, antenna systems,

telecommunication lines, faraday cages fall of potential,selective or stakeless

PQ troubleshooting, quantify the effectiveness of grounding

by measurement fall of potential, selective or stakeless




45/65


Introducing the Fluke 1623 and 1625 Ground Testers

Choosing the right instrument


46/65


Feature Summary Conventional 3 - and 4 - pole earth/groundtesting

Selective method Stakeless method Two pole AC resistance measurement

One button measurement press once tomeasure with simple GO/NOGO indicators Large easy to read display Rugged housing rated to IP56 2-Year Warranty

Customer Electrical Consultants, IndustrialApplication Verification of earth resistance of electrical

& communication systems.

Fluke 1623


47/65


Feature summary 3- and 4-pole measurement of earth

resistance

Selective and Stakeless method

Monitoring and display of probe and auxiliaryearth resistance

Automatic display of external voltage andfrequency

Selection of optimal measuring frequency(AFC)

measurements down to deep ground layerspossible (high testsignal power: >250mA,

48V)

Earth impedance R* of high tension towers- for calculation of genuine short circuitcurrent

Fluke 1625 - the expert instrument


48/65


Additional features of Fluke 1625 2 pole AC resistance measurement

- Resolution: 0.001 Ohm- Measuring signal: 20V / 250mA

2 pole, 4 pole DC resistance measurement- Range: 3 kOhm, resolution: 0.001 Ohm

- automatic polarity reversal, adaptation of testperiod- short circuit current >200mA as per IEC/EN61557-5 , UM >4V

User defined limit settings- adjustable limits for any individual applications

Interface and software available as option- data transfer to PC or printer- comfortable data evaluation with WinGEOsoftware



49/65


Unique: R* - Earth impedance

Measurement of complexearth-impedance at55Hz which determinesthe real short circuitcurrent



50/65



Measurement ofcomplex earth-impedance at 55Hzwhich determinesthe real short circuitcurrent

Unique: R* - Earth impedance


51/65


Introducing the Fluke 1623 and 1625 Ground TestersFeature 1623 1625

3-pole earth measurement

4-pole earth measurement

Specific earth resistance (soil-resistivity according to Wenner)

2-pole resistance measurement DC

4-pole resistance measurement DC

2-pole resistance measurement AC

Selective earth measurement (1 clamp)

Stakeless earth measurement (2 clamps)

Earth impedance of high voltage pylons (55 Hz)

Measuring voltage 20/48 V

Measuring voltage


52/65


Clamp-On Earth Loop Tester GEO 30

Feature Summary Ground loop resistance clamp measurement

Low level measurement of ground leakage current

Wide AC current measurement range up to 30A withone instrument

Rapid evaluation of continuity loop resistance by

audible HI/LO alarm Easy to use, convenient, Display-HOLD function

Time saving memory function for saving measuredvalues and automatic recording

Automatic self calibration ensures correctmeasurement every time

Customer Residential, Commercial, Industrial Electricians

Application Earth loop resistance testing for houses, commercial

and industrial buildings


53/65


Stakeless Ground Resistance MeasurementLEM GEO 30 - Ground Tester / Current Meter

The voltage U developed by the clamp is injected into

the circuit . This causes a current I which flows in this

measuring circuit . The second clamp measures this

current I and the earth clamp displays the ground loop

resistance Rx+Rn.

Current amplifier

Voltage generator

II

RxRn

U



54/65


Includes five language

operators manual

E/D/F/ES/IT

High quality,

rugged

carrying caseHigh Quality

measuring

instrument

Calibration loop for

instrument check



55/65


Target Customer Professional Electrician / Testing Specialist

Top Line Model with Unmatched performance

Features

Volts & Frequency to 500V

Insulation Resistance

Continuity Measurement Loop /PSC Measurement

RCD Testing

Earth resistance Tests

Phase Sequence Indication

On-Board Memory Interface for Downloading data

Fluke 1653


56/65


Summary

Resistivity measurement provides important dataregarding the earth material prior to system design

Fall of Potential Test is the most widely accepted

Four pole measurement compensates for voltage

drop in measuring cable The 62% rule provides some guidance to the

required distance for the temporary test spikes

Selective testing allows testing withoutdisconnection


57/65


Summary

Selective test is based on fall of potential test thatspeeds measurement and provides additional safety

Stakeless Testing is a fast method for multipleelectrode systems

Two pole ground testing provides minimal informationand should be used very cautiously

The Fluke 1623 provides the majority of the requiredfunctions for industrial users

The Fluke 1625 is the advanced ground tester forutilities


58/65


Why should I invest on Earth Ground?

The WW market for Earth Ground is estimated to be $25 Million

With only two major US competitors (AEMC, Megger), with inferiorproduct lines, there is no reason why Fluke shouldnt have 40%market share in 3 years.

Fluke 1623 and 1625 are the most complete Earth Ground testers

available anywhere In the US, Megger & AEMC do not have the best products, they

only have inroads into Utilities. Perfect value selling opportunity.

Your customers have been asking for i t

It is core to our strategy (along with PQ, Insulation andThermography)

Another opportunity to educate our customers about a productcategory. Take the high road, educate, convert to the bestproducts. Repeat what youve done again and again.


59/65


Earth Ground Market Segment

Elect Contractor -

Res & Comm Field Service

Industrial Maint

Technician

Utilities - Power &

Telecom

Handy GEO Handy GEO X

GEO 30 GEO 30 X X X X

Saturn GEO Plus Fluke 1623 X XSaturn GEO X Fluke 1625 X

Earth Ground Testing Methods

Selective Stakeless

3-Pole 4-Pole / Soil 1 Clamp 2 Clamp

Handy GEO Handy GEO XGEO 30 GEO 30 X

Saturn GEO Plus Fluke 1623 X X X X

Saturn GEO X Fluke 1625 X X X X

Fall of Potential

Who to target?


60/65


Function GEO 30

Handy

GEO

Fluke

1623

Fluke

1625 Comment

Can you test if the service is still

connected?

Yes Yes Yes

Handy GEO only performs the 3-Pole measurement which requires

the service to be disconnected. Fluke 1623, Fluke 1625, and GEO

30 can perform measurements whether the service is connected

(preferred by end users - safer) or disconnected.

Do you want to perform 3-Pole

or 4-Pole Fall of Potential testsusing stakes? Yes Yes Yes

GEO 30 only performs a stakeless test. All other testers can

perform these tests using stakes (Fall of Potential).

Are you performing tests inside a

building?Yes Yes Yes

Handy GEO cannot perform tests with clamps, necessary for

measurements inside a building, lacking access to soil.

Are any test points inside the

building larger than 0.9"

diameter?Yes Yes

The GEO 30 clamp has an inside diameter of 0.9". Fluke 1623 and

1625 have two sized clamps, 2" inside diameter (with kits) and 5"

inside diameter clamp for busbar applications (accessory). For

pylons, another accessory is the 12" inside diameter Split Core

Transformer, affectionately called Big Norma.

Are you interested in soil

resistivity?Yes Yes Necessary for new installations (buildings, substations)

Are there high power systems

close by that could influence

measurements?Yes

Utilities and other high end Industrial sites require the Fluke 1625,

because of the Automatic Frequency Control (AFC). If there are

influencing signals, the Fluke 1625 selects a different frequency to

measure.

Which product for which user?

Fluke

1653


61/65


1625 worth the money?

Why would anyone pay 650,- more for the Fluke 1625? Utility customers will pay because they see value in the following

advanced features:Automatic Frequency Control (AFC) identifies existing

interference and chooses a measurement frequency tominimize its effect, providing more accurate earth groundvalues

R* Measurement calculates earth ground impedance with 55Hz to more accurately reflect the earth ground resistance that afault-to-earth ground would see. Impedance is a frequencydependent measurement.

Adjustable Limits for quicker testing.

Power utility technicians are interested in two things: The ground resistance in case of lightning strike The impedance of the entire system in case of a short circuit

on a specific point in the line.


62/65


Product l ine-up

Delivery content

Fluke-1623: Basic GEO Earth Ground Tester

Contains: Fluke-1623 tester, test leads, batteries, manual (GB,FR, IT, DE, ES, PT)

Fluke-1625: Advanced GEO Earth Ground Tester

Contains: Fluke-1625 tester, test leads, batteries, manual (GB,FR, IT, DE, ES, PT)

Fluke-1623/1625 Kit: Advanced GEO Earth Ground Tester Kit

Contains: (1) Fluke-1623 or 1625 tester, (4) stakes, (2) 25m

cable reels, (1) 50m cable reel,(1) Sensing clamp, (1) Inducing clamp, all necessaryconnectors, test leads, batteries, manual,rugged carrying case


63/65


Accessories

EI-1623: Selective/Stakeless Clamp Set for Fluke-1623. Contains both the Inducing and Sensing clamp all necessary adapters Already in the Fluke-1623 Kit.

EI-1625: Selective/Stakeless Clamp Set for Fluke-1625. Contains both the Inducing and Sensing clamp all necessary adapters Already in the Fluke-1625 Kit.

ES-162P3: 3-Pole Stake Kit. (used for both the Fluke-1623 and Fluke-1625) Contains: (3) Stakes, (1) 50m cable reel of wire, (1) 25m cable reel of wire Already in the Fluke-1623 Kit/Fluke-1625 Kit.

ES-162P4: 4-Pole Stake Kit. (used for both the Fluke-1623 and Fluke-1625) Contains: (4) Stakes, (1) 50m cable reel of wire, (2) 25m cable reel of wire Already in the Fluke-1623 Kit/Fluke-1625 Kit.

EI-162BN: 320mm Diameter Spli t Core Transformer Used as a Selective clamp for ground loop resistance measurement around power

pylons Contains the split core transformer and all necessary adapters/connections


64/65


Marcom material

Distributor product announcement

Sales PPT

Value selling tool


65/65

QuestionsQuestions

and answers

MEDICIONES PUESTA A TIERRA PRESENTACION FLUKE.pdf

Documents

Transcript of MEDICIONES PUESTA A TIERRA PRESENTACION FLUKE.pdf