Partial Discharge Detection Products by EA Technology
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EA Technology is a consultancy and research firm specializing in power asset management and partial discharge services, operating for over 40 years as a 100% employee-owned entity. They provide products and services including condition monitoring equipment, fault location instruments, and asset management software, aimed at enhancing reliability and safety in power networks. Key innovations, such as the Ultratev and Cable Data Collector systems, focus on detecting and managing partial discharge to prevent outages and reduce maintenance costs.
Partial Discharge Detection Products by EA Technology
- 2. EATL History & Values • Originally established as R&D center for the UK Electricity Industry • Provides research, strategic engineering consultancy, HV asset condition assessment services, specialized instrumentation • Operating for over 40 years • 100% employee owned • Our mission is to deliver: •Tangible benefits •Demonstrate clear added values •Achieve customer objectives We focus on enhancing our customers’ profitability
- 3. People • Over 150 technical experts engaged in consultancy & high level technical services • Staff are experienced at providing technical solutions to owners & operators of power networks worldwide • World leading specialists in power asset management and equipment failure related to partial discharge • 40 years of technical know how in power networks Unrivalled intellectual excellence to engineering solutions
- 4. Products & Services Products • Substation Condition Monitoring equipment • Fault location & diagnostic instruments • Asset management software Services • Condition Assessment of overhead lines and towers • Power skills training • Forensic failure investigation EA Technology innovations become industry standard
- 5. Corporate Structure Group Management EA Technology LLC USA EA Technology Limited (UK) Group Operations Development Manufacturing Finance/Support Sales & Marketing Technology Middle East Europe Operations Asset Management Future Networks EA Technology Australia EA Technology Singapore EA Technology Shanghai
- 6. EA Technology LLC • Located in Denville, New Jersey (35 mi west of NYC) • Focused on providing high quality Instruments, Services, and Consulting to electrical power industry and private network owners. • Provides local stock, support, & calibration • Over 50 years experience in the electrical power industry. • Working with a network of Manufacturer’s Representatives, Service Partners and Rental Partners.
- 7. Partial Discharge (PD) the key to OUTAGE PREVENTION
- 8. Partial Discharge (PD) the key to OUTAGE PREVENTION PD measurement BUSINESS BENEFITS • Outage prevention • Improved reliability and safety • Reduced maintenance costs • Smarter replacement decisions BECAUSE PD is a factor in 85% of MV substation insulation failures
- 9. Partial Discharge (PD) the key to OUTAGE PREVENTION PD failure process • Multiple causes • Starts small • ALWAYS gets worse • Leads to FLASHOVER • Occurs at voltage peaks • Caused by field strengths in excess of insulation withstand capability
- 10. Partial Discharge (PD) the key to OUTAGE PREVENTION switchgear failure switchyard failure
- 11. What is Partial Discharge (PD)? Partial Discharge - A flashover of part of the insulation system due to a localized electric field greater than the dielectric withstand capability of that part where the overall insulation system remains capable of withstanding the applied electrical field. HF Current Pulse C1 C2 C3 Conductor Ground Void V withstand of C2 < applied field V withstand of C1&C3 > applied field 11 One effect of this flashover is a high frequency current pulse that travels through the capacitance of the insulation (C1 & C3)
- 12. Products of Partial Discharge 1 2 Partial discharge breakdown of insulation produces: Nitric Acid + Water Light, Heat, Smell, Sound, Electromagnetic Waves, and an HF Electric Current Electric TEV
- 13. Partial Discharge (PD) the key to OUTAGE PREVENTION Types of Switchgear • 3.3kV to 69kV • Indoor Metal clad switchgear cubicles • Indoor and Outdoor Insulators • Transformer Cable Boxes
- 14. Types of PD •Internal discharges occurring in defects, voids or cavities within solid insulation •Surface discharges occurring across the insulation surface Corona discharge occurring in gaseous dielectrics in the presence of inhomogeneous fields
- 15. Partial Discharge (PD) the key to OUTAGE PREVENTION internal PD Occurs in all types of insulation, including oil and gas
- 16. Partial Discharge (PD) the key to OUTAGE PREVENTION Surface PD Causes treeing and tracking
- 17. Practical Non-Intrusive Detection Methods Internal discharge activity • Transient Earth Voltage (TEV) Detection Surface discharge activity • Ultrasonic Emission • TEV Detection - when high amplitude surface discharge
- 18. INTERNAL DISCHARGE TEV Detection
- 19. Internal Partial Discharge Effect 1(current pulse - TEV) 1 9 PARTIAL DISCHARGE HV BUSBAR JOINT/GASKET HV BUSBAR HIGH FREQUENCY PULSE TO METALWORK VIA CAPACITANCE OF INSULATOR PULSE TRAVELS VIA SKIN EFFECT TEV RESULTS DUE TO IMPEDANCE OF GROUNDING At HF, PD currents are constrained to Flow in a thin layer on the surface of Conductor. Skin depth in mild steel at 100MHz 0.5um
- 20. Internal Partial Discharge Effect 1(current pulse - TEV) 2 0 PARTIAL DISCHARGE HV BUSBAR JOINT/GASKET HV BUSBAR HIGH FREQUENCY PULSE TO METALWORK VIA CAPACITANCE OF INSULATOR PULSE TRAVELS VIA SKIN EFFECT TEV RESULTS DUE TO IMPEDANCE OF GROUNDING At HF, PD currents are constrained to Flow in a thin layer on the surface of Conductor. Skin depth in mild steel at 100MHz 0.5um UltraTEV
- 21. PARTIAL DISCHARGE HV BUSBAR JOINT/GASKET HV BUSBAR EM EM WAVE WAVE 2 1 Internal Partial Discharge Effect 2(EM Wave) PULSE TRAVELS VIA SKIN EFFECT TEV RESULTS DUE TO IMPEDANCE OF GROUNDING This effect is usually less than the current pulse unless the PD is phase to phase! UltraTEV
- 22. Phase to Phase Partial Discharge (current pulse – NO TEV) 2 2 PARTIAL DISCHARGE HV BUSBAR JOINT/GASKET HV BUSBAR – Phase A HIGH FREQUENCY PULSE FROM PHASE TO ANOTHER. NO CURRENT PULSE ON METALWORK UltraTEV No TEV reading HV BUSBAR – Phase B HV BUSBAR – Phase C
- 23. 2 3 Internal Partial Discharge Overhead insulator (TEV) PULSE TRAVELS VIA SKIN EFFECT TEV RESULTS DUE TO IMPEDANCE OF GROUNDING Insulator Discharge Conductor UltraTEV
- 24. 2 4 Internal Partial Discharge Overhead insulator (EM Wave) EM Wave PD Hawk
- 25. TEV from PD EMI from PD Corona PD Hawk PD Spectrum (Simplified) • Partial Discharge causes a broadband EMI emission (approx. 3-3000 MHz) • Corona causes a smaller band EMI emission (30- 400 MHz) • TEV caused by capacitive currents are typically in the 3-80 MHz band • PD Hawk is typically set to approx. 800 MHz
- 26. 2 6 Probable Background Interference Probable Internal No Internal Significant Discharging Possible Surface Discharging Probable Floating Metal Bad Conn
- 27. TEV Interpretation 2 7 Background level Above 10 dB Below 10 dB Eliminate Background where possible and continue TEV Level on switchgear Within 10 dB of Background More than 10 dB Above background No significant Internal Discharging Pulses per cycle 1-50 PPC Above 150 PPC Above 150 PPC 8-150 Around 100 PPC Probable Interference TEV Level on switchgear Pulses per cycle More than 50 dB Below 25 Probable Bad Connection Probable Floating Metal TEV Level on switchgear < 20 dB > 20 dB Probable internal Discharge < 10 dB No significant Internal Discharging 10 - 45 dB Probable Surface Discharge confirm with Ultrasonic
- 28. Example 1: Failure of Cast Resin CT Long term erosion of insulation leading to flashover and failure
- 29. Cable Termination Screen Failure
- 30. Background Interference A B C D E F Battery charger Radio mast DC Light fitting Mobile phone mast HV OHL Variable speed drive Switchboard
- 31. Surface Discharge - Ultrasonic Detection
- 32. Sound Emission In severe cases, sound may be audible Less severe deterioration may be detected using ultrasonic detecting instruments Sound spectrum in the 40kHz range Characteristic sound more important than absolute level
- 33. Cracks / contaminated surface Carbonised tracking Surface Discharge Discharge noise can be picked up with Ultrasonic detector via gap • Measurement relies on an air path out of the switchgear • Types of access – Cable box vents – CB Bushings / HV spouts – Gaps around panel joints – Bolt holes Contact probe Designed to work though cabinet metalwork, no direct air path needed
- 34. Environmental Factors • Moisture in air will play a significant role in whether discharge is active • When monitoring ultrasonically the environmental conditions (%RH and Temperature) should also be monitored 100 90 80 70 60 50 40 30 20 10 0 29/03/2005 00:00 03/04/2005 00:00 08/04/2005 00:00 13/04/2005 00:00 18/04/2005 00:00 23/04/2005 00:00 28/04/2005 00:00 03/05/2005 00:00 08/05/2005 00:00 10 9 8 7 6 5 4 3 2 1 13/05/2005 00:00 Date %RH, Temperature 0 Level of Ultrasonic Activity °C %RH Ultrasonic
- 35. Ultrasonic Survey (Practical Considerations) • Influenced by environment (e.g. temperature, humidity, pollution). • Discharge has a distinctive crackling noise. • Often intermittent, particularly during early stages. • Severity of discharge is not necessarily related to noise amplitude.
- 36. Possible Ultrasonic Background Interference •Vibration from switchgear panels •Normal transformer ‘hum’ •Noise from adjacent plant and machinery •Very high EM PD activity •Corona from HV OHLs •Electronic interference from light fittings •Battery chargers and DC panels •Rustling of clothes e.g. waterproof coat •Other people in substation
- 37. Surface Discharge Activity Detected by Ultrasonics
- 38. Surface Discharge Activity •Discharge across surface of insulation towards earth or phase to phase discharge •Often characterised by low amplitude but very high discharge rate
- 39. Moisture Ingress leading to surface tracking
- 40. Surface Discharge on 11kV Cast Resin Circuit Breaker Spouts
- 41. Surface Discharge Activity Detected by Ultrasonics
- 44. 11kV CB Porcelain Spout Fixed HV spout (Porcelain) Film of sticky petroleum jelly CB Bushing (Resin) Remedial Action Cleaned Off with dry lint free wipes
- 45. Raychem Sleeve 2mm Crossed Remedial Action Replace the last few metres of the cable by putting in a new joint and termination
- 46. Corrosion due to PD activity •Corrosion as a result of PD activity •PD activity forms nitrous oxide gases •In the presence of moisture can produce nitric oxide and a very corrosive environment
- 47. Surface Discharge and Internal Discharge Differences Internal PD External PD Not affected by Humidity Affected by Humidity 0.5-8 Pulses per Cycle 8-30 Pulses per Cycle Rarely Audible Often Audible Detected best by TEV Detected best by Ultrasonic Thin Double Spike on PD Hawk Wide Double Spike on PD Hawk Hold UltraTEV against metalwork Hold UltraTEV at airgaps
- 48. Partial Discharge and Transformers!!!!! The ultraTEV line is particularly suited to finding PD in cable boxes, insulators, and bushings on transformers. The PD Hawk is well suited to finding PD in exposed insulators and bushings on large transformers. TEV inside the oil filled cavity is not typically detectable due to: • Most PD in transformers occurs between windings which does not generate TEV Ultrasonic detection (ours and competitors) inside the oil filled cavity is of limited use because: • The oil significantly dampens ultrasonic noise • The transformer hum overwhelms most other signal sources
- 49. Partial Discharge and Transformers!!!!! Acoustic emission detection systems do exist and can detect and localize PD in large oil filled transformers but: • They are hugely expensive and complicated to operate • They are only applicable to large oil filled transformers • Our instrument line is complementary to those devices as they can’t do what the UltraTEV and PD Hawk can do. Dissolved gas analysis is still the most accepted way of determining the health of large transformers
- 50. Partial Discharge (PD) the key to OUTAGE PREVENTION Detect PD Techniques
- 51. UltraTEV Detector™ dual-sensor PD detection tool surface/airgap: ultrasonic internal: TEV IDEAL FOR first pass surveys of surface and internal PD activity
- 52. UltraTEV Detector™ dual-sensor PD detection tool surface/airgap: ultrasonic internal: TEV TRAFFIC LIGHT display indicates PD levels
- 53. UltraTEV Detector™ dual-sensor PD detection tool substation entry working in substations ESSENTIAL personal safety device: warns of dangerous PD activity in working environment
- 54. complete kit • Easy to use • Portable • Rugged UltraTEV Detector™ dual-sensor PD detection tool features • Fast • Factory-calibrated for accuracy • Minimal training need
- 55. Partial Discharge (PD) the key to OUTAGE PREVENTION MEASURE PD techniques
- 56. UltraTEV Plus+™ multi-functional Partial Discharge (PD) instrument • Built on the knowledge and experience of over 30 years of PD testing •Menu driven backlit color LCD screen and keypad •Long-life rechargeable Li-Ion battery • Lightweight, tough, ergonomically designed
- 57. UltraTEV Plus+™ multi-functional Partial Discharge (PD) instrument surface/airgap: ultrasonic internal: TEV Provides two techniques to QUICKLY locate & measure surface and internal PD activity
- 58. TEV Measurements •Measurement of internal TEV activity in range 0 – 60dBmV •Two measurement modes – Continuous – Single Shot •User adjustable alarm thresholds •Traffic Lights default UltraTEV Detector levels •50/60Hz adjustable system frequency
- 59. TEV Functions •Two TEV display options •Display with rolling bar graph indication and traffic light alarm level indication •Display with amplitude, pulses per cycle and severity values
- 60. Ultrasonic Measurements •Measurement of surface discharge activity in range – -7dBμV to 68 dBμV •Hetrodyned audible output with high quality headphones •External ultrasonic sensor port •User adjustable alarm thresholds – Preset to UltraTEV Detector levels
- 61. Ultrasonic Features •Separately adjustable Gain and Volume settings •Immediate Red / Green indication based on user adjustable alarm threshold
- 62. Ultrasonic Optional Accessories •Optional external flexible microphone to extend reach •Optional external parabolic dish for surveying of overhead assets •Contact microphone for use when no air path is available
- 63. Partial Discharge (PD) the key to OUTAGE PREVENTION PD techniques
- 64. UltraTEV Locator™ portable Partial Discharge (PD) investigation system surveys locates SURVEYS & LOCATES PD activity in all substation assets – including cables
- 65. UltraTEV Locator™ portable Partial Discharge (PD) investigation system measures records MEASURES & RECORDS PD activity in all substation assets – including cables
- 66. UltraTEV Locator™ portable Partial Discharge (PD) investigation system RFCT cable sensor Ultrasonic Contact ProbeTM PLUG-IN OPTIONS for greater versatility
- 67. UltraTEV Locator™ portable Partial Discharge (PD) investigation system features • Locates PD source to <10cm (<4”) • Measures & records PD in all substation assets • Minimal training need
- 68. UltraTEV Locator™ portable Partial Discharge (PD) investigation system
- 69. UltraTEV Locator™ portable Partial Discharge (PD) investigation system complete kit • Easy to use • Portable • Rugged
- 70. 7 1 Cable Data Collector™ Partial Discharge (PD) detection in cables • A Cable Testing System that detects Partial Discharge activity in live MV cables • Easy to use, portable and rugged solution for determining cable condition • Can be used on Single Phase or Three Phase cables • Requires little training and no PD expertise to collect data
- 71. 72 Cable Data Collector™ Partial Discharge (PD) detection in cables How It Works
- 72. 7 3 Cable Data Collector™ Partial Discharge (PD) detection in cables • The CableData™ Collector is a Cable Testing System that detects and measures Partial Discharge activity in live medium voltage (3.3KV to 69KV) cables • Provides quick, safe and non-disruptive testing • Uses Radio Frequency Current Transformers (RFCT) to measure radio frequency currents produced along the cable • Can be used on Single Phase or Three Phase insulated cables up to several kilometres in length (maximum length varies and is determined by background noise, size of discharge and cable type)
- 73. 7 4 Cable Data Collector™ Partial Discharge (PD) detection in cables • Designed to be small, portable and rugged to withstand to rigors of use in industrial environments • Connects to a laptop running the CableData™ Collector software allowing data to be captured quickly and easily and for it to be stored for offline analysis using CableData™ Analysis Software • Plug and Play – plug it in and start working! • CableData™ Analysis Software allows offline analysis of captured data and producing of reports summarizing any activity discovered during testing
- 74. 7 5 Cable Data Collector™ Partial Discharge (PD) detection in cables •The CableData™ Collector Solution consists of three components • CableData™ Collector Instrument (left image) • CableData™ Collector Software (center image) • CableData™ Analysis Software (CDAS) (right image)
- 75. 76 CableData™ Collector Solution - Hardware • Powered and controlled from a USB port on laptop/netbook • Four channels of dedicated high speed, wide dynamic range analogue input allowing simultaneous acquisition giving cleaner signals and better analysis output • Variable gain blocks on each channel to allow detection of both small and large amplitude signals • Sophisticated Digital Signal Processing and Filtering to allow PD to be detected even when obscured by large levels of noises – no external filters and no knowledge required
- 76. 77 CableData™ Collector Solution – Cable Data Analysis Software (CDAS) • Application to import and display data collected using a CableData™ Collector instrument • Displays Waveform and Phase Resolve Event data on interactive charts • Provides the ability to map discharge activity along cable length • Allows condition reports to be created using the imported data
- 77. Cable Data Collector™ Partial Discharge (PD) detection in cables • Captured data analysed on software suite • Allows classification and analysis of cable PD data • Retrospectively see the effects of different filters • Identify local discharge and discharge down cable 78 Powerful data analysis
- 78. 79 Collecting Data Collecting data is quick and easy: 1. Clip the RFCTs around the earth straps of the cables to test and connect to the instrument using BNC cables 2. Connect the Phase Reference Transformer to the CableData™ Collector 3. Connect the CableData™ Collector to the laptop and launch the CableData™ Collector Software 4. Enter asset details about the cable under test and click the Start button. Data is captured and stored with no intervention required
- 79. PD Emission PD Hawk™ switchyard PD locator SAFELY locates internal PD activity in open terminal switchgear
- 80. How it works • Narrowband radio receiver (10 MHz) • Phased antenna array provides directionality (45 degree cone) • Tunable center frequency (avoid interference) • Usually tuned to 800 MHz (ignores corona) • RF demodulator moves sound to audio range (use headphones for discrimination) • Built in Spectrum Analyzer function Lithium Ion Battery Speaker Display and controls PD Hawk™ switchyard PD locator
- 81. PD Hawk™ switchyard PD locator business benefits • Prevents costly failures • Rapid return on investment • Gathers valuable data on asset condition • Extends asset life
- 82. Directionality • Design causes off center signals to be attenuated • Signals closest to center detected strongest • Directionality up-down and left-right • Rotate instrument 90 degrees to account for polarization Signals detected In this range Signals out here are rejected Signals out here are rejected PD Hawk™ switchyard PD locator
- 83. PD Hawk™ switchyard PD locator Sweep the Hawk around substation while rotating 90 degrees to compensate for polarization
- 84. PD Hawk™ switchyard PD locator Safely approach the locations with highest levels and aim at specific assets
- 85. Record or download data for reporting or comparison with future readings Android Tablet/Phone App PD Hawk™ switchyard PD locator
- 86. PD Hawk™ switchyard PD locator complete kit • Easy to use • Portable • Rugged
- 87. Partial Discharge (PD) the key to OUTAGE PREVENTION PD techniques
- 88. • Detection • Location • Measurement • Recording • Communication • Alarms • Analysis • Interpretation • Reports UltraTEV Monitor™ substation monitoring and alarm system 24/7 MONITORING of substation assets
- 89. UltraTEV Monitor
- 90. UltraTEV Monitor 1.High precedence resolution and dynamic range (1ns, 12 inches) 2.Can support up to 250 TEV measuring points 3.Detailed coverage, every channel of every node is monitored independently and continuously. No multiplexing between channels and no lost data. 4.Ultrasonic sensors improve coverage for surface discharges, two per node. 5.Cable PD measurement via dedicated CT inputs. This includes magnitude measurement, waveform capture and precedence for PD location. 6.Contact probe for switchgear temperature measurement at each system node.
- 91. Example Node Power & Status LEDs Ultraso nic Inputs Cable PD Input TEV Input Aux Power Input Sensor Status LEDs Test and Reset Buttons Communications
- 92. Example Sensors External TEV Sensor Ultrasonic Sensor Antenna (for cancelling background noise) Environmental Sensor
- 93. Single Discharge Site – Neither precedence or magnitude alone provide a good indication of location and severity of discharge – Precedence is very good for location – Magnitude when combined with precedence gives a good measure of severity
- 94. Magnitude Source B Single Discharge Sites Magnitude Source A Precedence Source A Precedence Source B Severit y – Magnitude and precedence measured on a pulse by pulse basis. – Allows magnitude profile for each source to be isolated providing improved measurement accuracy. – 1ns precedence resolution gives exceptional location accuracy.
- 95. 96 Instance Profile – Data Selection
- 96. 97 Select Monitoring Time Period Select the generated period Summary Report
- 98. Thank you For further information Call +1 862 261 2759 or Email sales@eatechnologyusa.com