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Megger MFM 10-M User Manual
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Megger MFM 10-M User Manual

Megger MFM 10-M User Manual

Sheath fault location system
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Consultation with Megger
MFM 10-M
Sheath Fault Location System
USER GUIDE
Issue:
Article number:
05 (07/2016) - EN
128313372
1

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Summary of Contents for Megger MFM 10-M

  • Page 1 Consultation with Megger MFM 10-M Sheath Fault Location System USER GUIDE Issue: 05 (07/2016) - EN Article number: 128313372...
  • Page 2 Consultation with Megger...

  • Page 3: Consultation With Megger

    E: team.dach@megger.com  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 4: Terms Of Warranty

    During the period of warranty, Megger agree to repair faulty parts or replace them with new parts or parts as new (with the same usability and life as new parts) according to their choice.

  • Page 5: Table Of Contents

    Contents Contents Consultation with Megger ....................3 Terms of Warranty ......................4 Contents ........................... 5 Safety Instructions ................... 7 Basic Notes ......................7 General Safety Instructions and Warnings ............8 Technical Description ..................10 System Description ..................10 Technical Data ....................12 Connections, Controls and Display ..............

  • Page 7: Safety Instructions

    Safety precautions This handbook contains basic instructions for the commissioning and operation of the MFM 10-M. For this reason, it is important to ensure that the manual is always available to authorised and trained personnel. Operating personnel should read the manual thoroughly.

  • Page 8: General Safety Instructions And Warnings

    Megger products in direct contact with water, aggressive substances and inflammatory gases and vapours is prohibited. The MFM 10-M is built to be robust and can withstand the stresses it can expect to be subjected to in demanding everyday use. Nevertheless, it is a precision measuring device which needs to be treated with the appropriate care.
  • Page 9 • fire fighting, this may lead to damage at the electrical installation. Megger disclaims any liability for consequential damage. Furthermore, when using a powder extinguisher near high-voltage installations, there is a danger that the operator of the fire extinguisher will get an electrical shock from a voltage arc-over (due to the powder dust created).

  • Page 10: Technical Description

    Function To detect sheath faults, the MFM 10-M works in test mode with a voltage of up to 10 kV kV (negative polarity), which also permits cables with a thicker outer sheath to be tested.
  • Page 11 Technical Description Features The MFM 10-M combines the following features in a single device: • Easy and comfortable operation via rotary encoder (EasyGo) and touch screen • Bipolar measurement • Prelocation by means of the voltage drop method with a direct measurement of resistance •...

  • Page 12: Technical Data

    Technical Description Technical Data The MFM 10-M has the following parameters: Parameter Value Output voltage 0 … 10 kV DC, bipolar Output current 750 mA at 0.4 kV, 200 mA at 0.5 … 1.5 kV, 60 mA at 5 kV,...

  • Page 13: Connections, Controls And Display

    Technical Description Connections, Controls and Display The MFM 10-M has the following connections, controls and display: Element Description Touch-screen display USB port On/off push-button HV “interlock” key switch “HV ON” push-button “HV OFF” push-button Rotary encoder...

  • Page 14: Commissioning

    Commissioning Commissioning Safety instructions for commissioning The safety guidelines for the operation of mobile testing systems often • differ from one network operator to another and are frequently subject to national regulations (such as the German BGI 5191). Before the WARNING measurement session, find out what the applicable guidelines are and follow the rules set out therein precisely, in respect of the organisation...

  • Page 15: Electrical Connection: Typical Procedure

    Commissioning Electrical Connection: Typical Procedure The following figure shows the simplified connection diagram: Connection diagram Observe position / order Although the illustrated complex connecting method is only required when prelocating a fault, it works for all operating modes. Under certain conditions also simplified / special connecting methods can be applied (see page 17).

  • Page 16: Step Description

    For detailed instruction on how to establish the connections, please refer to the test van’s operating manual. Unwind the cable from the special MFM 10-M cable reel. Connect the yellow connection lead to the earthing busbar of the cable system that is to be tested.

  • Page 17: Electrical Connection: Special Applications

    Commissioning Electrical Connection: Special Applications If the MFM 10-M is only to be used in testing, burning or pinpointing mode, an Simplified connection methods auxiliary conductor is not necessarily needed. Accordingly, in these operating modes, the wiring at the far cable end can be omitted while all connecting leads except of the...
  • Page 18 Commissioning Prelocation using one This method of prelocating a fault should only be used when absolutely unavoidable, auxiliary conductor only e.g. when no second, fault-free auxiliary conductor is available. The precision will be impaired in the same way as the simple Murray loop bridge is impaired by the effects of the contact resistances, but should remain comparatively higher.
  • Page 19 Commissioning Prelocation of non- Using the MFM 10-M, it is possible to locate non-earthed faults in inner conductors. In earthed inner MV cables with standard cross sections in particular, faults with a fault resistance of several MΩ can be prelocated to within a few metres.
  • Page 20 Under certain circumstances, prelocation can also be performed on a spooled cable is direct access to both which allows the MFM 10-M to be connected directly to both end of the cables. ends of the cable To prelocate an inner conductor fault, the cables only have to be connected to the two...

  • Page 21: Operation

    Operation Operation Switching On the System In the first step, the test van has to be switched on and prepared for MFM 10-M operation. For detailed instructions on how to control the test van, please refer to the respective operating manual.
  • Page 22 Operation The operation of the system with the rotary encoder is as follows: • Select a menu item • Increase or decrease the value of a variable parameter • Call up the selected menu item • Confirm the settings made Alternatively, almost all the steps can be accomplished directly on the touch screen.
  • Page 23 Operation Status bar The status bar at the bottom of the screen provides the following information: System information (tap to view) Firmware Date / Time version Adjusting the test or When setting a variable parameter, the following view appears: measuring parameters The value of the parameter can then be varied by turning the rotary encoder within the permissible range of values and pressing it briefly to confirm.

  • Page 24: Security Mechanisms

    The safety circuit’s The following conditions must be fulfilled in order to perform tests under high voltage: conditions • The test van has been prepared for MFM 10-M operation and HV readiness has been established. • The HV “interlock” key switch must be in the position.

  • Page 25: System Settings

    Operation System Settings The setup menu which is divided into following categories can be accessed via the menu item from the main menu: Category Setting Description General Date / Time Correct date and time settings are required for the logging function. Sprache Selection of the interface language.

  • Page 26: Operating Modes

    5 to 10 minutes depending on the cable type. A test of the inner insulation of a PILC cable should last between 25 and 30 minutes. At a setting of 0 minutes, the MFM 10-M runs in continuous operation mode and must be stopped manually.
  • Page 27 Operation Procedure Proceed as follows to perform insulation testing: Step Description In the main menu, call up the menu item Set voltage and test duration in accordance with the type of cable to be tested (see previous page). Start the test via the menu item Press the “HV ON”...

  • Page 28: Prelocating A Fault

    / or conductor material) or the same cross section and conductor material along the entire cable length. When set to Cable sections, the MFM 10-M will request the parameters for the cable sections at the end of the prelocation measurement. In that...
  • Page 29 Operation Procedure Proceed as follows to perform fault prelocation: Step Description In the main menu, call up the menu item Set the voltage, the cable length and the type of cable (see previous page). Start the fault location via the menu item Press the “HV ON”...

  • Page 30: Pinpointing A Sheath Fault

    Pinpointing a Sheath Fault - Introduction During sheath fault pinpointing, the MFM 10-M transmits direct current pulses at an adjustable rate into the shield affected by the earth fault. With each coupled pulse, the current flowing into the ground forms voltage gradients in the area around the fault, the centre of which can be located precisely with the assistance of a sheath fault locator and its earth rods (step voltage method).
  • Page 31 Start the pinpointing via the menu item Press the “HV ON” push-button Result: The MFM 10-M with the set pulsing couples the DC pulse in the shield affected by the earth fault. Devices equipped with the "AF" option transmit a 8.44 kHz audio frequency signal in parallel.

  • Page 32: Burning

    Operation 4.5.4 Burning - Introduction The available current of up to 750 mA also enables a fault conversion by the so-called “burning” of difficult sheath faults (e.g. high-impedance or intermittent faults). In which the thermal reaction to the electric arc converts the hydrocarbons of the cable insulation at the fault location into conductive carbon.
  • Page 33 Operation Step Description Terminate the burning process by pressing the “HV OFF” push-button The burning process will stop automatically after 5 minutes, if by this time it hasn’t been stopped manually. Between two time-consuming burning operations the unit needs to cool down for a few minutes! CAUTION Afterwards, try to prelocate (see page 28) the sheath fault again.

  • Page 34: Concluding The Test

    The test object is to be earthed and short-circuited as well as checked that it has been completely discharged (e.g. using a properly sized discharge rod). Afterwards, the MFM 10-M can be disconnected from the test object. Follow the five safety rules (see page 8).

  • Page 35: Processing Log Data

    Processing Log Data Processing Log Data When log data are exported after a test is complete, the files are written to the \Prot directory on the USB flash drive. The name of the file is comprised of the current date and a serial number. For larger test series, making notes about the sequence of the tests is recommended to make classify them easier later on.

  • Page 36: Updating The Firmware

    Result: The directory structure of the USB flash drive should then look as follows: Plug the USB flash drive into the USB port of the MFM 10-M which has to be switched off. Turn the power of the MFM 10-M off and on again.

  • Page 37: Maintenance And Care

    Maintenance and Care Maintenance and Care It is not necessary to open the housing of the device to commission and operate the system. Opening the housing causes the immediate termination of all warranty claims! The connections and connection leads of the system must be regularly tested to ensure that they are free of defects and intact, in accordance with the applicable national and company-specific arrangements.
  • Page 39 Maintenance and Care Tento symbol indikuje, že výrobek nesoucí takovéto označení nelze likvidovat společně s běžným domovním odpadem. Jelikož se jedná o produkt obchodovaný mezi podnikatelskými subjekty (B2B), nelze jej likvidovat ani ve veřejných sběrných dvorech. Pokud se potřebujete tohoto výrobku zbavit, obraťte se na organizaci specializující se na likvidaci starých elektrických spotřebičů...