ON-LINE PARTIAL DISCHARGE TESTING OF OUTDOOR HV PLANT by rik19085

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									   ON-LINE PARTIAL DISCHARGE TESTING OF
             OUTDOOR HV PLANT
– APPLYING EXPERIENCES FROM 10 YEARS OF PD
              TESTING INDOORS

     Lee Renforth*, Ross Mackinlay*, Malcolm Seltzer-Grant†
     *IPEC High Voltage Ltd †The University of Manchester


            19th CIRED 2007 Session 1 Paper 0675
                  Round Table Discussion 1.B
     On-line PD Testing Technology
             and Philosophy
1.     PDSurveyorTM – Handheld PD testing device for MV
       cables and switchgear
          …PD Surveying the Plant
2.     OSM LongshotTM – PD testing and mapping device for
       cables, switchgear, solid-insulated plant
       …Detailed PD Testing and Locating on the Plant
3.     Mini Monitor – Basic monitor for installation at RMU –
       MV Cables and Switchgear
       …Simple PD Monitoring of the Plant
4.     Intelligent Monitor – Temporary/permanent monitor
       …Intelligent PD Monitoring of the Plant



Renforth et al – UK - Session 1 - Paper 0675
    Integrated use of Technology




  Survey


                                   Spot Test




                                               Monitor
Renforth et al – UK - Session 1 - Paper 0675
                       PD Spot Testing
• Benefits and Uses
     – Quickly screen equipment for PD
     – Simple data collection
     – Post-collection analysis by experienced user (if
       required)
     – Short term spot-test or temporary monitoring
     – 24 hour tests can observe PD variation with load
     – Commissioning tool to verify installation quality
• Drawbacks
     – Intermittent PD can go undetected
     – Experienced users required in the field
Renforth et al – UK - Session 1 - Paper 0675
                             Plant Tested
“Indoor”
• PILC (paper) and XLPE (polymeric) Cables
• Air, SF6 and Solid Insulated Switchgear

“Outdoor”
• Cable Sealing Ends
• Voltage Transformers
• Current Transformers

Renforth et al – UK - Session 1 - Paper 0675
    Application to Outdoor Cable
Terminations and other Outdoor Plant
  • Common problems :-
        – RF Interference
        – Interference from other discharges:-




             Surface Discharges                Corona
          (Weather and Atmosphere)

Renforth et al – UK - Session 1 - Paper 0675
      New Techniques Developed
• “Shielded” Measurement System
       – Local sensors:
                                                                            RF Antenna
         HFCT and TEV                                                       (Shield)



       – Non-local sensors:                              TEV

                                                                             Longshot Unit
         RF Antenna. Used                                  HFCT


         to “shield” local
         sensors from
         interfering signals                       RF Antenna
                                                   (Shield)



                                           Example of sensor connection arrangements for on-
                                                 line PD testing at cable sealing ends




Renforth et al – UK - Session 1 - Paper 0675
   New Techniques in Development
• Precedence Detection Software
     – “Which pulse came first” algorithms
     – Distinguishes internal, external, local and non-
       local activity
     – Further applications:-
          • Localising PDs to a cable feeder on the busbar in
            spot test or monitor mode
          • Localising PDs to a switchgear bay on the busbar
            in spot test or monitor mode

Renforth et al – UK - Session 1 - Paper 0675
  Precedence Software Screenshot




Renforth et al – UK - Session 1 - Paper 0675
Discrimination of Internal and External
  PD in Outdoor Cable Sealing End
                                                                                                                                                                                    Available Waveform Display




                                                                                                                                             Chan 1
                                                                                                                                                       0                                                                                         Red Phase TEV
 50Hz Power Cycle


                                                                                                                     Chan 2
                                                                                                                                         0                                                                                                       Yellow Phase TEV
                                                                                                                0.005
                                                                                            Chan 3


                                                                                                                    0
                                                                                                               -0.005
                                                                                                                                                                                                                                                 Shield TEV
                                                                         Chan 4




                                                                                                0.05
                                                                                                   0
                                                                                               -0.05
                                                                                                                                                                                                                                                 Red Phase HFCT
                                                                                                                                                           0    2        4          6         8        10     12     14       16   18       20
                                                                                                                                                                                                  Time (mSec)
                                                                                                                                     Available Waveform Display
                                                                                                                                                           Chan 1              Chan 2             Chan 3    Curs 1        Chan 4   Curs 2
                        0.15                      0.03          0.03                      0.03                                                                                                                     PD Pulse (≈20mV) on Red Phase
                              0.1                 0.02          0.02                      0.02
                        0.05                      0.01          0.01                      0.01
                                                                                                                                                                                                                   PD with large associated HFCT pulse
   Chan 4


                     Chan 3


                                         Chan 2



                                                                Chan 1




                                0                       0                0                      0
                      -0.05                  -0.01             -0.01                      -0.01                                                                                                                    Final Conclusion: Internal to the sealing end)
                         -0.1                -0.02             -0.02                      -0.02
                      -0.15                  -0.03             -0.03                      -0.03


                                                                                                     0                              50                    100                 150                     200
                                                                                                                                                      Time (nSec)

                                                                                                             Chan 1                     2      Chan 3      Curs 1
                                                                                                                                   Chan Available Waveform Display           Chan 4          Curs 2

                                        0.06                0.006        0.015                   0.03
                                                                                                                                                                                                                   Different PD Pulse (≈20mV) on Red Phase
                                        0.04                0.004         0.01                   0.02
                                        0.02                0.002        0.005                   0.01                                                                                                              PD with no associated HFCT pulse (green)
            Chan 4


                               Chan 3


                                                   Chan 2




                                                                             Chan 1




                                           0                   0                      0                  0
                                   -0.02
                                   -0.04
                                                       -0.002 -0.005
                                                       -0.004            -0.01
                                                                                               -0.01
                                                                                               -0.02
                                                                                                                                                                                                                   Final Conclusion: External to the sealing end
                                   -0.06               -0.006 -0.015                           -0.03                                                                                                               – Surface Discharge
                                                                                                             10               20               30      40       50       60             70         80
                                                                                                                                                        Time (nSec)

                                                                                                                  Chan 1             Chan 2           Chan 3    Curs 1        Chan 4         Curs 2




Renforth et al – UK - Session 1 - Paper 0675
    On-line Mapping for Cables with
          Transponder System
                 SUBSTATION A
                                                                      SUBSTATION B

                                               Earth Straps

                                           Detection HFCT



                                           Pulse Injection
                                              HFCT


         OSM Longshot                                                          DISCHARGE TRIGGER UNIT
                                                                                             6

                                                                                               4
                                                                                                     +
                                                                                                         8
                                                                                                                   POWER
                                                                                     50 Ohms                               TRIGGERED
                                                                                      OUT                          ON
                                                                                           2                  10

                                                                                           Min          Max

                                                                                 INPUTIN           INPUT GAIN _            PULSE OUT

                                                                               DISCHARGE TRIGGER UNIT
                                                                                             6
                                                                                                     +             POWER
                                                                                               4         8

                                                                                     50 Ohms                               TRIGGERED
                                                                                      OUT                          ON
                                                                                           2                  10

                                                                                           Min          Max

                                                                                 INPUTIN           INPUT GAIN _            PULSE OUT




                                                                              Portable
                                          HV Cable – up to 5km long         Transponder




Renforth et al – UK - Session 1 - Paper 0675
Example of On-line PD Mapping
                                            Available Waveform Display

             0.015                                                                              Conventional,
              0.01
             0.005                                                                              single-ended
  Chan 1




                 0
             -0.005
                                                                                                cable mapping
              -0.01
             -0.015
                                                                                                waveform
                       2            4          6        8       10         12    14     16
                                                        Time (uSec)

                       Chan 1                                    Curs 1               Curs 2
                                            Available Waveform Display

              0.015
               0.01
              0.005                                                                            Waveform with
    Chan 1




                  0
             -0.005                                                                            Transponder Pulse
               -0.01
             -0.015


                            4           6          8    10      12         14   16    18
                                                        Time (uSec)

                           Chan 1                                 Curs 1              Curs 2


Renforth et al – UK - Session 1 - Paper 0675
                        PD Location Map
                      33kVMap of Circuit Stuart St - Queens Park (tee– 2677m long
                        PD Mixed Paper/Polymer/EPR Eastlands)
     9,000                                                                            All

     8,000
                 PD Levels = 6,200pC and 9,100pC
     7,000

     6,000

     5,000

     4,000

     3,000

     2,000

     1,000

        0
             0    5   10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
                                       Location (% along cable)



 •   The accuracy of the On-Line PD location in this case was 0.4% (10m)
     and 0.7% (18m) of the cable length

Renforth et al – UK - Session 1 - Paper 0675
   Summary of Monitoring Solutions
            for Cables
• Portable Monitor – OSM LongshotTM (can
  run for up to 1 week)
• Semi-Permanent/Permanent Monitors with
  distributed RMU Monitors




               RMU Monitor
                                               Permanent Monitor

Renforth et al – UK - Session 1 - Paper 0675
                     Integration of Permanent PD Monitors into the Network
                            Primary Substation Monitor plus distributed RMU Monitors




      Distributed
      SSM MINI


                                       Primary 11-33kV              16x Feeder Cables
                                       Substation                 SmoothSurvey™ PD monitor




                    Distributed
                    SSM MINI

RMU

                                  Range of Detection for SmoothSurvey™ PD Monitor :          Extended range from SSM-Mini:
Cable                                                                                           either 1 - 2km or 1- 2 RMU’s
Joint                                 either 1.5km - 2.5km or 2-3 Ring Main Units
                             Conclusions
• PD Testing Philosophy Presented based
  on using simple to advanced technologies
• New techniques have been developed for
  testing at outdoor cable terminations
  increasing the numbers and types of cable
  that can be tested on-line
• Precedence techniques developed will be
  reapplied to existing technology to
  enhance its functionality

Renforth et al – UK - Session 1 - Paper 0675

								
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