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AEMC instruments GROUNDFLEX 6474 User Manual

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User Manual
ENGLISH
6474
GROUNDFLEX
ADAPTER
®
WITH AEMC
INSTRUMENTS
®

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Summary of Contents for AEMC instruments GROUNDFLEX 6474

  • Page 1 User Manual ENGLISH 6474 GROUNDFLEX ADAPTER ® WITH AEMC INSTRUMENTS ®...
  • Page 2 Statement of Compliance Chauvin Arnoux , Inc. d.b.a. AEMC Instruments ® ® certifies that this instrument has been calibrated using standards and instruments traceable to international standards. We guarantee that at the time of shipping your instrument has met its published specifications. NIST traceable calibration is only possible when the Model 6474 is connected to the Ground Tester Model 6472.

  • Page 3: Table Of Contents

    Table of Contents INTRODUCTION ..................3 International Electrical Symbols ............4 1.2 Definition of Measurement Categories ..........4 1.3 Receiving Your Shipment ..............4 1.4 Ordering Information ................5 1.4.1 Accessories and Replacement Parts ........5 GROUNDFLEX ADAPTER ..............6 ® 2.1 Control Features ..................6 2.2 GroundFlex Sensor ................7 ® 2.2.1 Calibration of GroundFlex Sensors ........8 ® 2.3 Measurements in AUTO Mode ............10 2.3.1 Preparation of the GroundFlex...

  • Page 4: Introduction

    CHAPTER 1 INTRODUCTION WARNING These safety warnings are provided to ensure the safety of personnel. Please read and comply with these precautions: • This instrument is protected from accidental voltages of not more than 50V with respect to earth in measurement CAT IV. The guaranteed level of protection of this equipment may be compromised if used in a manner not specified by the manufacturer. • Safety is the responsibility of the operator. • All metal objects or wires connected to the electrical system should be assumed to be lethal until tested. Grounding systems are no exception. • Never exceed the maximum rated voltage and current, and the measurement category. • Never exceed the protection limits, and always comply with the conditions and place of use, indicated in the specifications.

  • Page 5: International Electrical Symbols

    1.1 International Electrical Symbols Signifies that the instrument is protected by double or reinforced insulation. This symbol on the instrument indicates a WARNING that the operator must refer to the user manual for instructions before operating the instrument. In this manual, the symbol preceding instructions indicates that if the instructions are not followed, bodily injury, installation/sample and/or product damage may result.

  • Page 6: Ordering Information

    1.4 Ordering Information NOTE: The GroundFlex Adapter Model 6474 only operates in combination ® with the Ground Tester Model 6472 Kit - 500ft. GroundFlex Field Kit (Model 6472 and 6474) ......Cat. #2136.03 ® Includes: (Ground Tester Model 6472 Kit-500 ft (Cat #2135.54)); Model 6472, one carrying bag, two 500 ft.

  • Page 7: Groundflex ® Adapter

    CHAPTER 2 GROUNDFLEX ADAPTER ® 2.1 Control Features GroundFlex ® Sensor SENSOR TURNS 50V CAT IV To Model 6472 Overload SENSITIVITY INPUT 1-2-3 1-2-3-4 GroundFlex Adapter ® For Use with the MODEL 6474 Ground Tester Model 6472 1. Inputs 1 through 4 for GroundFlex sensors ®...

  • Page 8: Groundflex ® Sensor

    2.2 GroundFlex Sensor ® The GroundFlex sensors are placed around a conductor (tower leg or pole) and ® closed using a screw connector, which is part of the sensor. This closed loop is then used to make a contact-free measurement of the current flowing in the conductor (leg) it is wrapped around. These sensors are current measurement clamps but are able to enclose objects that are much larger. GroundFlex sensors are available in lengths of up to approx 24ft (8m) and can ®...

  • Page 9: Calibration Of Groundflex ® Sensors

    2.2.1 Calibration of GroundFlex Sensors ® Calibration is necessary for a new sensor, one that is no longer identified when a sensor has been replaced, or more than 2 lengths of extension cable is used. The calibration coefficients are then stored in the Model 6474. NOTE: Do not move or touch the GroundFlex sensor or the calibration loop ® during the calibration. This could cause errors. Start by identifying each sensor using the identification rings that are supplied with the Model 6474: (1) Brown (2) Red (3) Orange (4) Yellow • Connect the calibration loop between terminals H and E of the Model 6472. • Connect the Model 6472 and 6474 together using the connection cable. • Connect the GroundFlex sensor with the Brown ring to Input 1 of the Model ®...
  • Page 10 Set the switch of the 6472 to SET-UP. 2. Set the SENSOR TURNS switch to 4. 3. Set the SENSITIVITY switch to x1. 4. Set the INPUT SELECTION switch to 1. SENSOR TURNS SENSITIVITY INPUT 1-2-3 1-2-3-4 5. Press the Hz/OPTIONS button 5 times. The device starts by comparing the current I injected by the device into the calibration loop to the current I measured by the GroundFlex sensor. If they ® are different, the "CAL" symbol blinks to recommend a calibration. S x 1 AUTO NOTE: To avoid measurement errors, do not touch the GroundFlex sensor or ®...

  • Page 11: Measurements In Auto Mode

    6. To start the calibration, press 2nd + START. 7. The device calculates and stores a calibration coefficient for the GroundFlex ® sensor connected to channel 1. S x 1 AUTO This operation must be repeated for channels 2, 3 and 4; the INPUT SELECTION switch must be set to the corresponding position each time. The calibration values are now stored into memory. After calibration, the GroundFlex sensors must always be connected to their ® respective channels. NOTE: Always connect the same sensor to the same input. 2.3 Measurements in AUTO Mode 2.3.1 Preparation of the GroundFlex Adapter...
  • Page 12 NOTE: • The sensors have arrows to indicate a direction. • All sensors should face the same direction. (clockwise or counter-clockwise around the tower legs) • All sensors should have the same number of wraps. • Sensors should encircle both leg AND ground system. To the Model 6472 6474 3. On the Model 6474, set the INPUT selection switch accordingly. You can mea-...

  • Page 13: Making A Measurement (Resistance Of Legs)

    2.3.2 Making a Measurement (Resistance of Legs) 1. Place auxiliary electrodes H (Z) and S (Y) on opposite sides of the tower, as far away as possible (100-150 ft) and, if possible, perpendicular to the high- voltage line (depth is not important). This will eliminate interference with the measurement by stray voltages or currents induced under the high-voltage line. NOTE: The H (Z) and S (Y) electrodes can be placed in the same direction if necessary.
  • Page 14 Overhead earth wire High-voltage lines 6472 4 GroundFlex ® sensors connected with the same orientation 6474 WARNING: If the GroundFlex Adapter Model 6474 is connected to the earth ® tester, the earth potential connected to the terminals E (X) and ES (Xv) will also be present at the BNC connectors of the GroundFlex sensors and at the ®...

  • Page 15: Other Measurements

    The device displays the following parameters: and its frequency, I , R-Act (R ), U-Act (U and its frequency, S-ES PASS S-ES and its frequency), I-Act (I and its frequency). To measure the resistances of electrodes H (Z) and S (Y), or if the resistance of the electrodes is too high, start the measurement by a long press (approx 2 sec) of the START/STOP button (you will hear a 2nd beep). will be displayed. H-E 2.3.3 Other Measurements As explained in Step 4 on the previous page, terminals ES (Xv) and E (X) must be connected to a metallic part of the tower above the GroundFlex sensor in order to ® measure the current flowing ISEL downward through the sensor towards the earth to measure ground resistance of the leg. If connections ES (Xv) and E (X) are placed below the GroundFlex sensor, the ®...
  • Page 16 In the sweep mode, the measurements can be made at frequencies up to 5kHz. On a single tower, frequencies in the order of 5kHz do not always entail inductive effects, but the "current loops" formed by the adjacent towers and the return channel through the ground may result in inductances that can be detected only at high frequencies. An equivalent diagram of the components forming this circuit is as follows: Overhead earth wire Point of injection of the current pylon Next pylon Pylon Next pylon to the left measured to the right A measurement in sweep mode (SWEEP) of an installation like this having 10 towers gives the following results assuming an earth resistance R of 10Ω for...

  • Page 17: Tower Testing Measurement

    2.5 Tower Testing Measurement 1. Connect the green Current (E) and black Voltage (ES) test leads to the grounding system to be tested using separate cables. Connection points should be side by side and above the GroundFlex (Rogowski) coil when ® testing tower leg resistance and/or impedance. Figure 1 2. Wrap the GroundFlex coils around the tower's leg(s). By increasing the ® number of turns around the tower's leg(s), the resulting measurements will be more robust. All coils must have the same number of turns around each tower leg. 3. Install all coils in the same rotational direction, either clockwise or counterclockwise. The coax cables on the GroundFlex sensors have arrows ® to indicate the rotational direction that must be consistent between tower legs. On towers with 3 or 4 legs, the sensors must be in sequence from one leg to the next. Figure 2 2.5.1 Choosing the positions for the H, S electrodes: 1.
  • Page 18 NOTE: The resistance for the H and S electrodes to earth should each be below 1kΩ to ensure good test results. Figure 3 3. For the most accurate measurements, roll the cable completely out to eliminate any inductance problems in locations with high overhead energy from the HV line. Normally errors are in the milliohm region when the cables are not fully removed from the spool. 4. Confirm that the umbilical cable connection between the 6472 and 6474 is secure. Check the position of the rotary switches (Input, Sensor Turns and Sensitivity) on the 6474 to be sure they match the test requirements (see Figure 4). 5. Make sure the number of turns between tower legs are the same. The number of turns must correspond to the number of turns used on the installed GroundFlex coils on each tower leg. ® Figure 4 6. Use input switch position "1-2-3-4" for measurement of the total pylon earth current on four leg towers. Use the corresponding switch position for 2 (1-2) and 3 (1-2-3) leg towers. 7. Start the test with x10 amplification. 8. Turn the rotary switch on the model 6472 to the GroundFlex position. The ® 6474 amplifier will turn on after the 6472 is powered on and the calibration of the connected GroundFlex sensors will be verified. The Overload LED ® will come on for a few seconds during power up. If this LED is flashing continuously and the 6472 is beeping continually, then the current in the GroundFlex sensor(s) are too high for the selected amplification. Reduce to ®...
  • Page 19 First check (see Figures 5, 6, 7, and 8): Figure 5 Figure 6 1. Press the DISPLAY button until U-Act. and US-ES or UH-E is shown. U-Act. refers to live actual voltage. U S-ES equals measured voltage between S and ES. Disturbance voltage measurements on the S Probe and the H Auxiliary electrode will run continuously as long as a test has not been initiated with the START button. 2. Press the DISPLAY key again until U-Act. and UH-E is shown. UH-E equals the measured voltage between H and E. The frequency of US-ES or UH-E appears when the corresponding voltage is higher than 0.1V. The measured voltage is caused by the current flowing through the tower into the Earth. 3. Check if the values for UH-E and US-ES are equal. When UH-E equals US- ES, the electrodes are placed far enough from the potential influence of the tower legs. 4. If one of the values is smaller than the other value, you should reposition the electrode that shows the smaller voltage further away from the HV-line and check US-ES and UH-E again. 5. Press the START-button when both measurements are equal to each other for a reliable active measurement. When both US-ES and UH-E are close to zero, then the HV-line is not in service or the overhead ground conductor is completely corroded or disconnected. In this case, the total pylon current will be also nearly zero. 6. Press the DISPLAY button until ISEL appears. This is the total pylon earth current and is measured by the 4 GroundFlex sensors (channels 1-2-3-4 ®...
  • Page 20 7. Next, press the DISPLAY button until RPASS appears. A leakage current I-SEL, when induced in the pylon, produces a voltage drop US-ES (potential difference to Earth) on the earth-resistance of the pylon. Once the I-SEL and US-ES values are known, the 6472 can calculate RPASS (passive earth resistance). It has the advantage of being measured at the nominal frequency of the network but is also influenced by the load fluctuations in the network and by the potential influence of the HV-line. When the tower earth resistance is actively measured and is nearly equal to RPASS, the result will be reliable; otherwise, the potential relationship during the active and passive measurement will be different. Figure 8 (model 6472) Second check (See Figures 9): 1. Currents in the tower legs are measured continuously as long as the START- button has not been pressed. Switch the model 6474 to INPUT 1. Select ISEL on 6472 with DISPLAY button. Figure 9 2. Check the current in each tower leg by switching through each channel in sequence while noting the measurements of each. You can find corroded and/or disconnected earth connections as indicated by readings that show no current flow. 3. Check the sum of all leg current channels. If the total is approximately equal to the sum of the all individual leg currents, then the static wire (overhead ground conductor) is bonded to the tower properly. If not, this connection is probably corroded and only a small current will be flowing in the tower legs, which will be induced in the tower grounding. The sum will be very low, but, despite that, single currents may be higher because they can flow in different directions. The measurement of RPASS for individual legs has no value. Even when individual legs are not connected together. Below ground level, they will still influence each other.
  • Page 21 Third check (See Figure 10): 1. Start a measurement with a long press on the 6472 START button in the 4-pole switch position. This will initiate the test using 32 Volts and will provide the full complement of test results including auxilary rod (H and S) resistance. The measurement will be conducted at 128Hz. When a measurement is initiated with a long press on the START button (by holding down for approximately 2 seconds until a second beep is heard), you will then get additional results including the resistances of electrodes RH and RS. Both should be below 1KΩ if you want to perform a quality SWEEP test up to 5kHz. 2. If RH or RS is higher than 1kΩ, you can place more electrodes in parallel with each of them or you can moisten the soil in the area where the electrodes are placed. Parallel electrodes shall be placed at a distance of approximately 4x the depth of the H and S electrodes. RH should be as low as possible, because it determines the test current. The measurement precision is better when the test current is higher. Much of this current will flow through the overhead ground conductor, and only a small percentage will flow through tower legs into the earth. Test currents below 3mA can cause unreliable results, which are indicated by the flashing greater-than (>) and less-than (<) symbols to the left of the reading. When any input symbol is blinking on the display, it means that the corresponding lead is disconnected or broken. The measurement can be performed only if all connections are good. Figure 10 Measurements: When all parameters are in the "green zone" (proper range), 3 typical measurements on the tower can be accomplished. 1st measurement (See Figure 11): GroundFlex sensors measurement into the Earth ®...
  • Page 22 Figure 11 2nd measurement (See Figure 12): GroundFlex sensor measurement into static wire (overhead ground ® conductor) 1. Make sure the device is in SWEEP Mode. 2. Move the current injection wire E (green) so it feeds through the GroundFlex ® sensors on the tower leg and connects next to the potential connection. 3. Do not move the ES (black) potential connection. Figure 12 NOTE: In SWEEP mode a long press is automaticaly initiated and the measurements at each frequency used in the sweep are stored in memory Third measurement (See Figure 13): 4-pole Earth-impedance measurement (lattice network measurement) 1.
  • Page 23 4. The overhead ground conductor (OGC) connects the grounding systems of all towers in parallel at low frequencies, but at higher frequencies the inductance of the OGC starts to separate them such that the effective impedence of an individual tower can effectively be measured. 5. Measure the resistance/impedance in 10% increments between E and H. 6. Look for the plateau readings (usually between 50% and 70% distances to find the effective resistance/impedance of the structure under test. Figure 13 First check 1. Measure disturbance voltages UACT, US-ES, and UH-E. When US-ES and UH-E are close in value to each other, then the H and S electrodes are far enough away from the HV line. If they are different, move the electrode with the lower voltage further away from the HV line and recheck. When US-ES and UH-E are close to or equal to zero, the OGC is either badly corroded or disconnected. 2. Next, check RPASS and note it for later use. Second check 1. Check the current in each tower leg (IACT/ISEL) to find corroded or disconnected grounding points. (break)If the sum of all legs is approximately the same as the sum of all individual legs, then the OGC is intact. Third check 1. Press the START button with a long press to begin active measurements. Note the resistance of RH and RS. 2. If either or both are above 1kΩ, add more electrodes or moisten the soil around them to lower their resistance to Earth. 3. 1st Measurement: use SWEEP mode with the black and green wires connected to the tower leg above the GroundFlex sensor ®...
  • Page 24 Glossary E Terminal: is a green colored terminal and is the current injector terminal. It is also known as the X terminal ES Terminal: is a black colored terminal and is the voltage measurement terminal. It is also known as the Xv terminal. S Terminal: is a blue colored terminal and is the voltage return terminal. It is also known as the Y terminal. H Terminal: is a red colored terminal and is the current return terminal. It is also known as the Z terminal. HV Line: is the power line running from tower to tower. Top Line: is the overhead ground conductor also known as the sky wire in some areas. UACT: is the real-time voltage measured before running a test ISEL: is the total real-time leakage current measured RPASS: is the passive earth resistance measured at normal network frequency. SWEEP Mode: is a measurement mode where the 6472 takes measurements at 14 user selected frequencies between 40 and 5078 Hz. 4-Pole: refers to the number of terminals on the 6472 used in performing a test. Green Zone: refers to all conditions being within range to properly take measurements GroundFlex Sensor: also known as AmpFlex Sensor or Rogowski coil which is ® a flexible device used to measure AC current flow. U: used as the international symbol for Volts. US-ES: Voltage measured at the potential terminals. UH-E: Voltage measured at the injection terminals RH: Resistance of the injector electrode RS: Resistance of the potential electrode OGC: used as a term to indicate the overhead ground conductor also called static wire or sky wire Green Zone Conditions: RH and RS: Resistance of each should be less than 1 kΩ if either or both are...

  • Page 25: Specifications

    CHAPTER 3 SPECIFICATIONS 3.1 Electrical Measuring Method: Voltage/Current measurement with a rectangular AC signal Short Circuit Current: > 200mA Noise Suppression: > 80 dB at frequencies differing by 20% or more from the test frequency Max. Overload: 250Vrms Max. Value for R & R : 100kΩ Measuring Time: Short push on START: approx. 7 s for first value of R 128Hz, then 3 measurements per s. Long push on START: approx. 15 s for first value of R 128Hz, then 3 measurements per s. Pylon Measurement with GroundFlex ®...
  • Page 26 The operating error of AC resistance measurements can be less than that specified for voltage or current because frequency characteristics of the voltage channel are matched to those of the current channel. For test frequencies between 41 and 5087Hz, between 1 and 4 turns of the GroundFlex sensor, and a selection of 1 to 4 measurement channels, the ® operating accuracies are the following: SENSITIVITY and minimum I minimal Operating accuracy for R S-ES S x 1/10 >...

  • Page 27: Mechanical

    3.2 Mechanical Dimensions: 10.7 x 9.76 x 5.12" (272, 248 x 130mm) Weight: 7 lbs (3.2kg) approx Case Material: ULV0 Polypropylene Terminals: 4mm recessed banana jacks Case Protection: EN 60529 - IP53 (cover closed) Drop Test: Per EN 61010-1 Vibration Test: Per EN 61557-1 3.3 Environmental Operating Temperature: 32° to 113°F (0° to 45°C); 0 to 90% RH Specified Operating Temperature : 0° to 95°F (0° to 35°C); 0 to 75% RH Storage Temperature: -40° to 158°F (-40° to 70°C); 0 to 90% RH Altitude: < 3000m (1): This range corresponds to the one defined by standard EN 61557, for which an operating error including the quantities of influence is defined.

  • Page 28: Maintenance

    CHAPTER 4 MAINTENANCE Maintenance Please make sure that you have read and fully understand the WARNING section on page 3. • To avoid electrical shock, do not attempt to perform any servicing unless you are qualified to do so. • To avoid electrical shock and/or damage to the instrument, do not get water or other foreign agents into the case. • Turn the instrument OFF and disconnect the unit from all circuits before opening the case.

  • Page 29: Repair And Calibration

    Repair and Calibration To ensure that your instrument meets factory specifications, we recommend that it be sent back to our factory Service Center at one-year intervals for recalibration, or as required by other standards or internal procedures. For instrument repair and calibration: You must contact our Service Center for a Customer Service Authorization Number (CSA#). This will ensure that when your instrument arrives, it will be tracked and processed promptly. Please write the CSA# on the outside of the shipping container. If the instrument is returned for calibration, we need to know if you want a standard calibration, or a calibration traceable to N.I.S.T. (includes calibration certificate plus recorded calibration data). Ship To: Chauvin Arnoux , Inc. d.b.a. AEMC Instruments ® ® 15 Faraday Drive, Dover, NH 03820 USA Phone: (800) 945-2362 (Ext. 360) (603) 749-6434 (Ext. 360) Fax: (603) 742-2346 or (603) 749-6309 E-mail: repair@aemc.com (Or contact your authorized distributor.) Contact us for the costs for repair, standard calibration, and calibration traceable to N.I.S.T. NOTE: You must obtain a CSA# before returning any instrument. Technical and Sales Assistance If you are experiencing any technical problems, or require any assistance with the proper operation or application of your instrument, please call, mail, fax, or e-mail...

  • Page 30: Limited Warranty

    Limited Warranty The instrument is warrantied to the owner for a period of two years from the date of original purchase against defects in manufacture, unless the instrument was registered within 30 days of the purchase date (see warranty note below). This limited warranty is given by AEMC Instruments, not by the distributor from ® whom it was purchased. This warranty is void if the unit has been tampered with, abused, or if the defect is related to service not performed by AEMC ® Instruments. Full warranty coverage and product registration is available on our website at www.aemc.com/warranty.html. IMPORTANT WARRANTY NOTE: By registering online within 30 days of the purchase date, your warranty will be extended to 3 years. Please print the online Warranty Coverage Information for your records. What AEMC Instruments will do: ®...
  • Page 31 Notes:...
  • Page 32 10/22 99-MAN 100326 V11 AEMC Instruments ® 15 Faraday Drive • Dover, NH 03820 USA Phone: (603) 749-6434 • (800) 343-1391 • Fax: (603) 742-2346 www.aemc.com © Chauvin Arnoux, Inc. d.b.a. AEMC Instruments. All Rights Reserved.

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