PRIMARY CABLE FAULT LOCATING MIKE PESCHEL & DAVE BOYER HIGH VOLTAGE, INC. COPAKE, NY hvinc

1. PRIMARY CABLE FAULT LOCATING MIKE PESCHEL & DAVE BOYER HIGH VOLTAGE, INC. COPAKE, NY www.hvinc.com VLF Hipots – Tan Delta – Fault Locators – AC & DC Hipots - Oil & Aerial Lift Testers

2. WHY DO YOU NEED TO KNOW ABOUT FAULT LOCATING?

3. NON DC METHODS OF CABLE TESTING ARE IN YOUR FUTUREVLF HipotingPartial Discharge TestingTan Delta Testing

4. WHEN PERFORMING ELEVATED AC VOLTAGE CABLE TESTING, FAILURES MAY OCCUR. FAULTS MUST BE LOCATED. WHY NOT BY YOU?(Customer Care & Increased Revenue)

5. MOST COMMON METHOD OF FAULT LOCATING IS TO USE:CAPACITOR DISCHARGE SYSTEMSWITH TDR/RADAR&FAULT PINPOINTING DEVICESACOUSTICAL AND ELECTRO-MAGNETIC

6. SUBJECTS COVERED Capacitor Discharge Systems – Thumpers Time Domain Reflectometry – TDR/RadarAcoustical & Magnetic Listening Devices

7. COMMONLY USED TERMS Thumper - a device that develops a HV pulse output Capacitive Discharge Fault Locator - a thumper Joules - the energy in a stored capacitor = ½ CV2 Burn - a technique to deliver high current to a fault TDR - Time Domain Reflectometry HV Coupler - allows connection of the TDR to the thumper Arc Reflection - a TDR method that utilizes the HV Arc of the fault to reflect a TDR pulse Current Surge or Impulse - a thumper technique that measures the thumper pulse reflection from the fault or end of the cable (standing waveform) URD - Underground Residential Distribution

8. COMMONLY USED NAMESThumpers (mostly in the US)Surge Generators (most of the world outside US)Impulse Generators (occasionally used)Bangers (the Brits of course)Thumpers Ay (Canada)

9. WHAT IS A THUMPER? A device to apply a high voltage and high energy pulse to a faulted cable to make a loud arc at the fault to help find it. Used with a TDR to pre-locate the fault, and/or your ear or electronic listening device to hear it, and/or a device to sense the magnetic impulse coming from the arc.

10. CAPACITOR DISCHARGE SYSTEMInternal capacitors are charged to a voltage level Charged capacitor is connected to cable - BANG Stored energy of capacitor is dumped at the fault Loud noise and electro-magnetic pulse occurs Hear the noise and measure the electromagnetismUse Arc Reflection w/TDR to pre-locate fault

11. CAPACITOR DISCHARGE SYSTEM Modes of Operation Variable Hipot Output (some models) Capacitor Discharge Output Cable Burning (some models) TDR – Time Domain Reflectometry Arc Reflection

12. VARIABLE HIPOT OUTPUTA Very Useful & Often Necessary Feature Apply voltage to a cable to verify the fault and identify the bad cableApply voltage to learn the breakdown voltage of the fault to select output voltage tapBurn cable to decrease arc-over voltage to permit lower voltage, less damaging thumpingHipot the cable after repairEnhance the use of TDR/radar

13. CABLE BURNING Arc fault with hipot output and pump current through it to reduce fault impedance and arc-over voltage. Sometimes can cause a dead short to open slightly to enable arc. Thumper must have variable hipot output with high mA rating to be effective Can then use lower voltage tap to thump, causing less insulation damage. Find the fault w/o making more Most effective with oil insulated cable but also useful on XLPE and EPR

14. DISCHARGE OUTPUT VOLTAGE CONTROLLED ENERGY THUMPER Thumpers should have several output voltage taps all at the full joule rating. Permits thumping at lower voltages but with full energy.

15. FOR EX: HVI UNITS HAVE THREE VOLTAGE RANGES @ FULL ENERGY Model CDS-2010U: 0 - 5/10/20 kV @ 1000J Model CDS-3632U: 0 - 9/18/36 kV @ 3200J Thumping at lower voltages yet at full joules is possible and preferable to minimize cable damage while easily finding the fault. Noise of 1000 joules at 5 kV = noise of 1000 joules at 20 kV

16. DISCHARGE ENERGY Measured in Joules= watts x seconds Sufficient energy must be delivered to the fault to create a loud discharge for ease in fault finding. The higher the joules, the louder the bang and more intense the magnetic pulse Today's thumpers range from 350J to 7500J

17. DISCHARGE ENERGY Joules = ½CV2 Full joule output is achieved at full voltage output. At half voltage output, only ¼ of the joules are delivered to the fault. A 25 kV thumper set to 15 kV will deliver only 36% of full energy, making fault locating difficult. Need thumper with multiple output voltages at full energy Voltage across caps uF rating of caps

18. TDR CAPABILITY Most modern thumpers all have internal “arc reflection filters”. Some thumpers have an integral TDR while most offer separate TDR

19. TDR SPLICE TRACE 4 splices

20. PRE & POST THUMP TRACES Pre-thump cable end Thump Trace - Fault location

21. REVIEW: IDEAL THUMPER DESIGN Can thump at low voltage yet deliver high joules Multiple full joule output voltage taps Fully variable hipot output Ample burn current TDR/Radar ready

22. Questions About Thumper Design & Features?

23. SELECTING A THUMPER Hipot Output Voltage Thump Output Voltage Burn Current Energy/Joule RatingInput Power – BatteryTDR Portability

24. SEVERAL SHAPES & SIZES

25. HIPOT OUTPUT VOLTAGE? Voltage rating of systems to be encountered? Voltage > line-to-ground V if needed to burn down faults to get under thump voltageFor ex: CF70 Thumper has 70kVdc hipot & 25 kV thumpWill thumper be used for hipoting cable? If not, hipot V can equal thump V, as with most present day thumpers

26. THUMP OUTPUT VOLTAGE? What is highest cable voltage rating?If thumper has no cable burning method, then a thump voltage 20% - 25% higher than the line-to-ground system voltage is neededMultiple voltage outputs desirable15kV systems need >10kV thump25kV systems need > 18kV thump35kV systems need > 25kV thump

27. CABLE FAULT BURNING Full featured thumpers have a variable hipot output with a high current rating, used to reduce the fault arc over voltage to permit lower voltage thumping. Look for thumpers with at least 100ma output to rapidly reduce fault impedance. Allows thumping at the lowest possible voltage yet delivering the highest possible energy. Find your fault without making more.

28. HOW MANY JOULES ARE NEEDED? What kind of cable insulation?What kind of distribution system?How long are the cables?Using only arc reflection or pinpointing?What listening device will be used?Power versus size and weight?

29. JOULES NEEDED? Arc reflection needs < 300J, like SectionalizersPinpointing using good listening device > 500J15 - 25kV URD needs ≥ 1000J w/o good list. dev. “Network” systems thumpers need > 2000JLong PILC cables need 2000 – 3000J

30. JOULE RATING EXAMPLES 500J HDW 350J 560J 1000J 3200J IUP Hipotronics HVI HVI

31. INPUT POWER – BATTERY? Some vendors offer battery - some do not. Mostly lower power thumpers have battery. High power thumpers with battery offer very short battery time and limited or no hipot/burn. Some offer 15 seconds between discharges to minimize battery drain. Too long between thumps. If battery a must, study compromises resulting

32. PORTABILITY Compromises Size & Weight vs. Power & FeaturesSuitcase thumpers good for sectionalizing URD loops but not best for other uses

33. REVIEW: THUMPER SELECTION System Voltage? Insulation type? Cable length? TDR Needed? Hipot/Burn Needed? Input Power?

34. IDEAL THUMPER DESIGN ALL THE FEATURES NEEDED Can thump at low voltage yet deliver high joules Multiple full joule output voltage taps Fully variable hipot output Ample burn current TDR/Radar ready

35. MODEL DEMONSTRATED TODAY High Voltage, Inc. CDS-2010U • 0 - 5/10/20 kVdc outputs • 1000 Joules at each voltage • 400 ma Burn current • Internal Arc Reflection filter • 6 – 9 second thump rate • 50’ output cables • 250 lbs

36. SPECIALTY FAULT LOCATORS VLF/Thumper Combination Sectionalizers (suitcase thumpers) Battery Operation

37. VLF THUMPER - VT33 Combination VLF AC Hipot and Thumper Complete URD Cable Care System For Cable Ratings Up To 25kV • VLF Output: 0 - 33 kVac peak • Load Rating: 1.0 uF @ 0.1 Hz ~ 1.5 miles of 15/25 kV cable • Discharge: 0 – 13 kV @ 760 J • VLF Cable Burning Mode • TDR/Radar Ready • VLF source for PD & TD testing

38. VLF THUMPER • VLF test 25 kV cables up to 1.0 uF (~1.5 miles) • Pre-locate faults with arc reflection – TDR • Pinpoint faults with continuous cap discharge • Burn faults with VLF to more easily find them • Verify cable after repair with VLF hipot • Use for tan delta & partial discharge testing

39. SECTIONALIZERS FaultWizard IUP Corp. SaidiSaver VON Corp. EZ-Restore HDW Corp.

40. SECTIONALIZERS Used for fault finding in loop systems. EffectiveTake one shot (hopefully) and read where the fault isIsolate that section and restore power

41. SECTIONALIZERS Small, light, very portable. Ideal for trouble trucksNot designed to replace larger thumpers often brought in later to pinpoint faultSome models can thump continuously, some not.May or not be good for NETA types depending on situation

42. BATTERY OPERATED THUMPERS Hipotronics Von

43. BATTERY OPERATED THUMPERS If battery necessary, beware of drawbacks Battery life can be short Very low mA burn rating or no hipot/burn at all Long discharge cycle some models Keeping battery charged Higher cost

44. BATTERY OPERATED THUMPERS HDW ElectronicsModel SG15-1150MHipot: 0 – 7.5 kV & 15 kV Discharge: 0 – 7.5 kV & 15 kVEnergy: 1150 joulesBurn current: 28 mA Thump Rate: 5 – 7 secondBattery Time: Depends on useWeight: 200 lbs

45. BATTERY OPERATED THUMPERS Von Corporation Model XF25-1563v.2 Hipot: None Discharge: 0 – 12.5 & 25 kV Energy: 1563 joules Burn current: None Thump Rate: 15 seconds Battery time: Depends on use Weight: ~250 lbs

46. Questions About Selecting The Right Thumper?

47. TIME DOMAIN REFLECTOMETRY - TDR

48. WHY USE TDR Pre-locate fault in minutes with just one or two thumps Walk to location and continuously thump 20 – 30 times while listening. Pinpoint fault to dig hole or pull cable Alternative is to thump continuously and walk for hours listening for fault. Wastes time and harms cable with hundreds of thumps

49. TIME DOMAIN REFLECTOMETRY The TDR outputs a low voltage pulse that travels down the cable “looking” at the insulation between the conductor and shield. Any change in resistance reflects some of the signal back to TDR. TDR produces a “picture” of the cable. It measures distances, find opens or shorts, find transformers, splices, and shows other accessories.

50. TDR SPLICE TRACE 4 splices