Megger SMART THUMP ST25-30 User Manual
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Megger SMART THUMP ST25-30 User Manual

Portable / vehicle mounted fault locating system
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ST25-30-UG-EN-V03
User Manual
Portable / Vehicle Mounted
Fault Locating System
SMART THUMP ST25-30
covering units with and without
MULTI SHOT Capability
Read this entire manual before operating.
M
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403-2329
U.S.A.
610-676-8500
www.megger.com

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  • Page 1 ST25-30-UG-EN-V03 User Manual Portable / Vehicle Mounted Fault Locating System SMART THUMP ST25-30 covering units with and without MULTI SHOT Capability Read this entire manual before operating. Valley Forge Corporate Center 2621 Van Buren Avenue Norristown, PA 19403-2329 U.S.A. 610-676-8500...
  • Page 3 Portable / Vehicle Mounted Fault Locating System SMART THUMP ST25-30...
  • Page 4 Copyright© 2019 by Megger. All rights reserved. No part of this handbook may be copied by photographic or other means unless Megger have before-hand declared their consent in writing. The content of this handbook is subject to change without notice. Megger cannot be made liable for technical or printing errors or shortcomings of this handbook.
  • Page 5 F:+61 (0)2 9397 5911 F: 416 298 0848 Germany India Kingdom of Bahrain Megger Germany Megger (India) Pvt Limited P.O. Box 15777 Dr. Herbert Iann Str. 6 501 Crystal Paradise Mall Office 81, Building 298 96148 Baunach / Germany Off. Veera Desai Road...

  • Page 7: Table Of Contents

    Table of Contents 1 SAFETY ............................1 Precautions ..........................1 Warning and Caution Notices..................... 1 Working with the Product ......................3 Operating Personnel ........................3 Repair and Maintenance ......................3 General Cautions and Warnings ....................3 Intended Application ....................... 3 What to Do if Equipment Malfunctions .................
  • Page 8 Locating a Faulty Cable Segment (Sectionalizing) ..............31 Introduction ........................31 How to Determine the Faulty Section ................32 How to Verify Whether it is Actually a Bad Section ............34 Locating a Cable Fault (shielded MV power cable) ..............35 How to Test the Dielectric Strength of the Cable ..............
  • Page 9 Representative or send to VFCustomerSupport@Megger.com. 2. Examine the equipment for damage received in transit. If damage is discovered, file a claim with the carrier at once and notify Megger, giving a detailed description of the damage. 3. Prior to operation, check for loosened hardware or damage incurred during transit.
  • Page 10 ST25-30-UG-EN-V03...

  • Page 11: Safety

    Precautions This manual contains basic instructions on commissioning and operating the SMART THUMP ST25-30 system. For this reason, it is important to ensure that the manual is available at all times to authorised and trained personnel. Any personnel who will be using the devices shall read and understand the manual thoroughly.
  • Page 12 ST25-30-UG-EN-V03...

  • Page 13: Working With The Product

    Repair and Maintenance Repairs and service must only be done by Megger or Megger authorized service departments. Megger recommends having the equipment serviced and checked once per year at a Megger service location.

  • Page 14: What To Do If Equipment Malfunctions

    The instruments should only be operated under tempered condi- tions. It is not allowed to operate Megger products in direct contact with humidity, water or near aggressive chemicals nor explosive gases and fumes.

  • Page 15: Important Safety Advisory Note - When Working With Hv Surge Generator / Thumper

    SAFETY that the operator of the fire extinguisher will get an electrical shock from an ARC FLASH (voltage arc-over created by the powder dust cloud). It is essential to observe the safety instruction on the extinguishing agent.  Applicable is DIN VDE 0132 in Germany ...
  • Page 16 4. The Concentric Neutral (shield of the cable to be tested) of the power cable, or the second faulty core of the cable to be tested must be bonded to the system grounding point of the power device (see also 1). 5.
  • Page 17 SAFETY ST25-30-UG-EN-V03...

  • Page 18: Technical Description

    System Description Functional Description The SMART THUMP ST25-30 is a compact fault location system typically to be used for fault locating of medium voltage power cables. It offers 2 or 3 power sources to be operated from, depending whether it is a vehicle mounted or portable version.

  • Page 19: Features

    12ft between the control head and the HV unit. The remote control head is installed in a Pelicase style instrument enclosure. This manual covers all models of the SMART THUMP ST25-30. If necessary, any differences are noted in the text. Features...

  • Page 20: Scope Of Delivery

     HV output cable hard wired  Safety Grounding cable  AC Power cord  Owner’s manual Available Accessories The following accessories* can be ordered from Megger, if required: Accessories Description Item number Elbow adaptor with 14 mm Used to connect HV output...

  • Page 21: Technical Data

    TECHNICAL DESCRIPTION Technical Data ST25-30-UG-EN-V03...
  • Page 22 Parameter Value DC Test voltage 0 to 30 kV Surge voltage 0 to 12.5/ to 25 kV Source current 40 mA (up to 12.5kV) 20 mA (up to 25kV) 5 mA (between 25 and 30kV) Insulation measurement 2 kΩ … 10 MΩ Surge energy 1600J @ the maximum voltage in each of both surge levels (12.5kV / 25 kV)
  • Page 23 TECHNICAL DESCRIPTION Weight 187lbs/85kg to 264lbs/120kg depending on selected model, incl. all items required to operate the specific model, e.g. HV cable and safety ground cable Protection class (in accordance with IEC 61140) Protection rating IP53 (open lid) (in accordance with IEC 60529) ST25-30-UG-EN-V03...

  • Page 24: Control Elements, Indicators And Connectors

    Control Elements, Indicators and Connectors The ST25-30 has the following control elements, indictors and connectors: External DC Terminals shown for portable version, similar for vehicle mounted Element Description Display 7 inch Emergency stop button HV key switch ST25-30-UG-EN-V03...
  • Page 25 TECHNICAL DESCRIPTION Element Description “HV ON” button “HV OFF” button Rotary control knob “ON / OFF” button USB port Charging status LED (yellow: charging | green: charging completed) AC power connector Safety ground connection Jack for connecting external safety device (See page 10 'Available Accessories').

  • Page 26: Power Supply

    Battery Operation Introduction If the SMART THUMP ST25-30 is equipped with an internal battery and fully charged, the unit can deliver more than 400 HV discharges (thumps) at 90% of full voltage (in each range). This equals approxi- mately 1 hour of...

  • Page 27: Backup Battery / Dc Power Supply

    TECHNICAL DESCRIPTION NOTE: To find out whether the battery charge is sufficient for further use of the unit in the field, turn the unit on in battery mode check, the battery symbol should show 4 green bars. Backup Battery / DC Power Supply If the internal battery is becoming drained while fault locating, any 12V battery or DC power source, provided it can source more than 50 A (e.g.
  • Page 28 ST25-30-UG-EN-V03...

  • Page 29: Setting Up The System

     around the test site to block access to the danger zone and prevent the risk of touching live parts. Always operate the SMART THUMP ST25-30 system in a vertical  position. Grounding and HV contacts both require a vertical orientation to ensure proper functioning as well as a “Fail Safe...

  • Page 30: Connection Diagram

    Connection Diagram The following figure shows the simplified connection diagram please review also important safety advisory on pages 4 and 5 110 V … 230 V ±15%, 50 / 60 Hz Connection Sequence Connect the unit in the following order: Step Description Connect the safety ground lead to a reliable ground (e.g.
  • Page 31 Setting up the System ST25-30-UG-EN-V03...

  • Page 32: Operating Instructions

    OPERATING INSTRUCTIONS Power on the System Once the "ON / OFF" button is pressed, the system starts up. After start-up, the system is in the 'Ready for operation' state and the main screen is displayed: The main screen image shows a typical set up with the 3 basic elements of fault locating, HIPOT, ARM PRELOCATION and PINPOINTING (other elements or modes of operation can be set up;...

  • Page 33: High Voltage Control

    OPERATING INSTRUCTIONS The currently selected menu item is identified by a red circle. not selected selected With the aid of the rotary knob, the individual menus can be accessed, and values can be entered. If a selected menu item requires a value to be adjusted, the following dialog is displayed: The value for the parameter can then be adapted by turning the rotary knob and clicking it again to confirm.

  • Page 34: Conditions Of The Safety Circuit

    mode, the system automatically switches the high voltage power supply off and discharges and grounds the HV output. A message will be displayed on the LCD display which must be acknowledged before any operation can be re-activated again. Conditions of the Safety Circuit The following safety conditions must be met in order to allow to perform tests under high voltage: must be in the...

  • Page 35: System Settings

    OPERATING INSTRUCTIONS This mode is only recommended to the group of users with extensive experience and expertise in the set-up and operation of the TDR. When selecting this mode, all automatic functions like auto-ranging and auto- gaining, and also the automatic detection of the cable end and the distance to fault have been turned off and must be adjusted manually.
  • Page 36 Menu item Description >> Trigger delay Delay time between the time of flash-over at the fault and the time to trigger and time capture the TDR trace. The delay time allows the flash-over to build up well before Only available in a measurement is done (ideally when the arc reaches it highest current).
  • Page 37 OPERATING INSTRUCTIONS Menu item Description Voltage When set to Manual the unit will always default to 0.1kV as a starting level in all selection HV modes. The operator must then adjust the HV level in any of the operating manual or modes and operation menus involving HV to the desired level (Quick-Steps, automatic Expert mode and Manual TDR mode).
  • Page 38 Menu item Description >> Set-up Start Procedure to adjust the start marker "zero" position to the end of the actual length Marker of the HV output cable, for portable ST25-30 at the end of the typical 50ft (15m) HV output cable; for vehicle mounted units typically optional cable reels are installed, and the Start Marker is set to the end of the output cable of the HV reel, could be 50ft (15m), 85ft (25m) or 130ft (40m).The procedure is fully automatic and the operator is prompted to perform the required steps:...
  • Page 39 OPERATING INSTRUCTIONS Menu item Description Stored Traces Menu item to export or delete all traces which have been stored in the internal memory. Exporting traces requires a USB flash drive plugged into the USB port . The traces are written into a EtrayTraces folder which is automatically created. The data can be viewed with any standard web browser by opening the index.html file which is also located in the EtrayTaces folder.
  • Page 40 Menu item Description Customize TDR Menu to configure the features which are available during measurement, for either features QUICK-STEPS mode or EXPERT mode See page 43; not available in Manual Operation, please see page 23 Return By leaving the EXPERT MODE through this menu item, the new settings are saved.

  • Page 41: How To Perform A Test

    HOW TO PERFORM A TEST Detecting and Locating a Cable Fault in a Shielded Medium Voltage Power Cable Locating a Faulty Cable Segment (Sectionalizing) Introduction The sectionalizing technique is used to trouble shoot single phase MV distribution loop circuits in order to identify the faulted section, so it can be quickly switched out, the rest of the circuit can be re-energized and the power outage kept to a minimum.

  • Page 42: How To Determine The Faulty Section

     Determine the distance to the fault using the ARM method (red trace, frozen)  Determine the number of transformers up to the fault & one beyond it  Based on relative position of fault to the 2 closest transformers the faulted cable segment can be identified and easily isolated How to Determine the Faulty Section Step...
  • Page 43 HOW TO PERFORM A TEST Description Step Select to discharge capacitor (only if measurement start option is set to manual (not required in automatic mode). See page 25. Result: A capacitor discharge (shot) is initiated. If a voltage breakdown takes place, the red fault trace is shown in the display. The red fault marker is automatically set to the position where both traces diverge from each other.

  • Page 44: How To Verify Whether It Is Actually A Bad Section

    How to Verify Whether it is Actually a Bad Section The HIPOT test within the context of Sectionalizing is done to confirm, that the section of cable identified as faulted during the Sectionalizing procedure can be verified to be actually faulted. Proceed as follows to perform a HIPOT test after the identified cable section has been isolated at the 2 closest transformers (DC HIPOT test cannot performed with the transformers still connected to the faulted cable section):...

  • Page 45: Locating A Cable Fault (Shielded Mv Power Cable)

    HOW TO PERFORM A TEST Locating a Cable Fault (shielded MV power cable) How to Test the Dielectric Strength of the Cable A HIPOT/breakdown test is used to test the dielectric strength of a cable under DC HV conditions, and in case the cable fails, provides the breakdown voltage.
  • Page 46 Step Description Breakdown A voltage breakdown took place at the indicted test voltage, meaning there at…kV was a flash-over at the fault No Flash-over The cable has withstood the applied DC test voltage. In this case no current will be indicated. If required, repeat the test with higher voltage (do not exceed the maximum permissible voltage) Cable not...

  • Page 47: How To Pre-Locate The Fault

    HOW TO PERFORM A TEST How to Pre-Locate the Fault Arc Reflection Method (ARM) For pre-location of a high resistance MVcable fault the SMART THUMP applies the widely approved and well-known ARM (Arc Reflection Method). Locating the fault is accomplished by comparing a reflection image (impedance) taken with a LV pulse (reference trace) to a reflection image (impedance) taken while an arc, ignited by sudden discharge of the charged capacitor, was present at the fault location (fault trace).
  • Page 48 Step Description NOTE: The software provides its best estimate for the cable end. If the trace beyond the flag “open at 950 ft” does not show any significant upwards or downwards reflection, then click to confirm. If there is a substantial reflection beyond this point, turn the rotary to the click and adjust the end marker manually to where the end of the cable is visible, then click to save and confirm.
  • Page 49 HOW TO PERFORM A TEST Step Description If required, the surge voltage can be adjusted via the icon, otherwise, the maximum surge voltage is automatically used, if AUTOMATIC VOLTAGE CONTROL has been selected as default. Press the green illuminated “HV ON” button Select to charge the capacitor (only if AUTOMATIC HIGH VOLTAGE RELEASE option is set to Manual.

  • Page 50: Current Decoupling (Ice)

    Current Decoupling (ICE) The ST25-30 SMART THUMP features the current decoupling method (ICE, Surge Pulse) as an alternative method to pre-locate high resis- tance (flash over) faults. It has proven very useful on very long (>5 mi/ 8km) and or PILC cable fault situations, where the standard ARM pre-locating method has failed to provide a concise and unambiguous di- stance to fault reading.

  • Page 51: How To Pinpoint A High Resistance (Flash-Over) Fault

    HOW TO PERFORM A TEST Step Description Result: A sudden capacitor discharge (shot) is initiated. If a breakdown takes place, a red oscillating curve is shown on the display screen. NOTE: If no trigger is received and, thus, no fault trace is shown, you may try to repeat the procedure with a higher surge voltage (if possible) by selecting the icon.

  • Page 52: Detecting A Sheath Fault In A Shielded Medium Voltage Cable Or A Ground Fault In An Unshielded, Low Voltage Cable (Both Must Be Directly Buried)

    If required, the surge voltage can be adjusted by selecting the icon. Pinpoint the fault within the pre-located area with a surge wave receiver like the Megger Digiphone Plus. For detailed instructions, please refer to the user manual of the surge wave receiver.
  • Page 53 HOW TO PERFORM A TEST Fault locating on unshielded, direct buried low voltage cables must be carried out in the sheath fault locating mode in order to ensure that the maximum voltage is limited to 5kV; in this case the HV out put cable is connected to the center conductor and the HV return to a driven ground rod.
  • Page 54 Step Description No Flash- The cable jacket has successfully withstood the applied DC test voltage. over The test can be repeated using the menu item. Cable not The cable shield could not be charged with the test voltage. This is chargeable caused by a short in the circuit (fault in the jacket).

  • Page 55: How To Pinpoint A Sheath Fault In A Shielded Medium Voltage Cable Or A Ground Fault In An Unshielded Low Voltage Cable (Both Must Be Directly Buried)

    If required, you can adjust the pulse voltage by selecting the menu item. Pinpoint the sheath fault with an earth fault locator like the Megger ESG-NT. For detailed instructions, please refer to the user manual of the earth fault locator.

  • Page 56: Customize Tdr Features (Applicable To Tdr And Arm Mode)

    CUSTOMIZE TDR FEATURES (applicable to TDR and ARM Mode) Introduction As soon as a trace has been recorded and is shown on the display, the operator can access up to 20 TDR Features in order to optimize the trace and display settings. The system configuration allows the user to display each of the 20 features as one of 3 categories, which can be individually selected by user for both modes of operation, QUICK STEPS and EXPERT MODE:...
  • Page 57 CUSTOMIZE TDR FEATURES ST25-30-UG-EN-V03...

  • Page 58: Customized Tdr Features

    Customized TDR Features The following table lists and describes all TDR features included in the system Menu item Description Adjusts the gain setting. By doing so, the amplification of the received signal and, thus, the amplitude of the Y-axis can be adjusted. Adjust Gain With an adjustment of the gain setting, the fault trace, if present, is erased and a new “live”...
  • Page 59 CUSTOMIZE TDR FEATURES Menu item Description Makes an exact copy (blue trace) of the “live” trace. NOTE: This function is very helpful when making a phase Copy trace, makes copy of live comparison on 3 phase MV circuits. trace when superimposing It is also very helpful when just using the TDR several traces...

  • Page 60: Completing The Operation

    Menu item Description Adjust Trigger Allows manual adjustment of the trigger delay time (see page 24). It Delay Time synchronizes the HV pulse with the LV TDR pulse to a reflection measurement at the highest or closest to highest current of the arc occurring (only for you units at the fault location.

  • Page 61: Advanced System Settings

    ADVANCED SYSTEM SETTINGS How to Edit the Cable List Introduction Cable lists are XML files which are stored in the internal memory and can be imported and exported (see page 28). By default, one cable list with a selection of prevalent cable types is pre-installed on the unit. XML Structure of a Cable List File The following example shows the XML structure of a cable list: <?xml version="1.0"...

  • Page 62: How To Edit The Cable List

    While the bolded parts must not be changed, there can be an arbitrary number of <cable> elements placed one after another each presenting a cable type. The <cable> element consists of the following mandatory and optional child elements: <attr name="TYPE"> Cable type (mandatory / unique) <attr name="MILS">...

  • Page 63: How To Setup Customer-Specific Tdr Features

    ADVANCED SYSTEM SETTINGS Step Action Import the new cable list into the unit. See page 28. Set the new cable list as default cable list. See page 28. How to Setup Customer-Specific TDR Features Thanks to the high level of configurability of the SMART THUMP, the TDR features for both, "EXPERT MODE"...
  • Page 64 Step Action Confirm the selection with If required, perform steps 6 to 8 for further options. The adjusted configuration can be shared among your units using the Export and Import functions of the Menu Locate Options menu. ST25-30-UG-EN-V03...

  • Page 65: How To Use Easyprot Software To Plot Dc Hipot/Sheath Test Data

    ADVANCED SYSTEM SETTINGS How to Use EasyPROT Software to Plot DC HIPOT/Sheath Test Data The ST25-30allows recording and graphing of DC test data, either DC HIPOT test data or Sheath test data. Before switching the ST16 on, insert USB drive into front panel. Then start the unit and conduct the particular test.

  • Page 66: Care And Maintenance

    CARE and MAINTENANCE Maintenance For installation and operation of the equipment it is not necessary to open the enclosure of the instrument. Opening the enclosure will void the warranty and liability of the manufacturer. Connections and connectors must be tested according to all applying standards (international, national and company own).
  • Page 67 MAINTENANCE ST25-30-UG-EN-V03...
  • Page 68 Appendix 1 Overview of TDR Features See next page for complete chart. ST25-30-UG-EN-V03...

  • Page 69: Overview Of Tdr Features

    OVERVIEW of TDR Features Option Recommended settings Your settings (mark with x) QUICK STEPS mode EXPERT MODE Disa. Simp. Ext. Disa. Simp. Ext. Cable Velocity (option to adjust the QUICK STEPS: simple cable velocity) Expert: simple Xfmr sensitifity (option to adjust the QUICK STEPS: disabled transformer sensitivity) Expert:...

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Smart thump 25-30

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