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					  H.V. TEST c.c.




Submerged Arc Furnace Contact Pad and
              Electrode
     Kilo Amp Monitoring System
                 by
            Ron Goodwin
            H.V. Test c.c
            South Africa
  H.V. TEST c.c.
                Introduction
• The system was designed to provide an accurate
  simultaneous measurement of the individual
  contact pad kilo Amps and summated electrode
  current.
• This has not been possible in the past.
• H.V. Test c.c. in South Africa have developed a
  unique system for the measurement of these
  currents.
• A number of these systems have been
  successfully operating on submerged arc closed
  top furnaces since 1998.
  H.V. TEST c.c.
                System Goal
• The measurement of the individual electrode contact pad
  currents (up to MegaAmps/pad) using current
  transducers, signal processing, isolation and a monitoring
  system.
• The system can be integrated into the existing PLC or
  similar furnace control system.
• The goal is to monitor and alarm each contact pad to
  determine when overloading or underloading occurs due
  to poor contact or green electrode problems.
• The system can record trends predicting contact pad
  problems, electrode slipping changes and possible green
  electrode problems.
     H.V. TEST c.c.
                   The System
• Each set of bustubes is monitored by the system and
  individual signals are transferred to the control room.
• These signals can be incorporated into the existing
  monitoring and recording system or into a dedicated PC.
• The PC will present a visual picture of the furnace, the
  electrodes and the contact pads.
• When a contact pad is being overloaded or underloaded the
  screen will alarm red or green together with an audible
  alarm.
• Next to each contact shoe, the current in kA will be
  reflected together with the phase current per transformer as
  well as the vectorily summated electrode current.
     H.V. TEST c.c.
              The System cont.
• Should the current on the contact pads vary dramatically
  this could be an indication of :
       • Poor Contact pad service pressure problems
       • Overslipping of the electrode and that a green
         electrode is eminent .
       • Indication of furnace mix problems
       • Electrode Breakages
       • Secondary Transformer winding overloading
       • Cooling water temperature problems
       • Electrode casing problems
H.V. TEST c.c.
         The System cont.

 • Cavitation in the electrode
 • Arcing of contact shoes
 • Double earthing problems
 • Possible under coaking
        H.V. TEST c.c.
                    Specification
• The transducers can be designed to suit your bustube diameter.
  From 50mm OD to +500mm OD.
• The transducers are of the split core type and can easily be
  secured around an existing Bustube.
• The transducers have to be wrapped in fiber glass tape to offer
  some protection to the transducers – they will withstand an
  ambient temperature of 150° Celsius maximum.
• Each electrode is serviced by a panel housing the signal
  conditioning, isolation and passive 4-20mA output signals.
• Accuracy: 5% of the full Kilo Amp range. E.g. For 4-20mA
  which is equivalent to 0-10 kA, the accuracy would be ±0.5kA or
  ± 0.8mA
      H.V. TEST c.c.
                Typical Matte Smelter
                                      SIGNAL                  4-20MA OUTPUT
                                    CONDITIONING                TO PLC (x48)
                                        (x48)



       FURNACE         CONTACT PAD               CONTACT PAD
     TRANSFORMER   MONITORING POINTS (x24)   MONITORING POINTS (x24)




       I2
I1




        I1+I2

                               FURNACE
       H.V. TEST c.c.
                Typical Delta Smelter
                SIGNAL              CONTACT PAD
            CONDITIONING (x8)   MONITORING POINTS (x8)


                                                                 FURNACE
     4-20MA OUTPUT                                            T RANSFORMER
        TO PLC (x8)

                                  I

                                                3I




                                          FURNACE             I

        SIGNAL                                                           SIGNAL
                                 3I                      3I
    CONDITIONING (x8 )                                               CONDITIONING (x8)



    CONTACT PAD                                                       CONTACT PAD
MONITORING POINTS (x8)                                            MONITORING POINTS (x8)
                                      I



     4-20MA OUTPUT
        TO PLC (x8)                                                   4-20MA OUTPUT
                                                                         TO PLC (x8)
H.V. TEST c.c.
Typical Transducer Installation
H.V. TEST c.c.
          Signal Cables
H.V. TEST c.c.
 Signal conditioning Cubicle
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    I/O Cable Terminations
H.V. TEST c.c.
 Typical Scada screen layout
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          Trend Records
           H.V. TEST c.c.
           Typical Matte Smelter System

SUMMATED ELECTRODE         28.493 KA                      26.263 KA                               26.343 KA

                             2.3       2.3                    2.0       2.1                        1.9       3.1
                               M       T                        M       T                                M    T
                     4.5 N                   4.2    3.5 N             3.5                   3.4   N                  3.5
                             ELECTRODE S                  ELECTRODE S                                ELECTRODE S
                                 2                                  4                                    6
                           O           R                  O                     R                  O           R
                     3.9                     4.3    4.3                             4.1     3.5                      4.1
                               P       Q                       P            Q                         P          Q
                             3.5       3.4                    3.5       3.3                        3.5       3.2

                             3.8       3.4                    3.4       3.4                        3.5       3.5
                                   H   I                        H       I                                H   I
                     5.0 G                   4.0   4.4    G
                                                                                      3.7   4.7   G
                                                                                                                     3.8
                             ELECTRODE J                    ELECTRODE J                             ELECTRODE J
                                 1                              3                                       5
                           F           K                  F           K                           F           K
                     3.2                     4.3   3.0                                3.9   3.0                      4.0
                               E       L                       E        L                             E       L
                             2.3       2.4                    2.1       2.6                        1.8       2.2

SUMMATED ELECTRODE         28.458 KA                      26.468 KA                                26.5 KA
    H.V. TEST c.c.
                Conclusion

• We believe that this monitoring system will
  provide the furnace operators with valuable
  information allowing optimised operation of
  the furnace.
• Productivity and Efficiency

• Production Costs
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posted:7/27/2011
language:English
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