Instruments Overview
Jul 08, 2015
Instruments Overview
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
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
Products & ServicesProducts
• 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
Corporate StructureGroup
Management
EA Technology
LLC USA
EA Technology
Limited (UK)
Group
Operations
Development
Manufacturing
Finance/Support
Sales &
Marketing
Europe
Operations
Asset
Management
Future Networks
Technology
Middle East
EA Technology
Australia
EA Technology
Singapore
EA Technology
Shanghai
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.
Partial Discharge (PD) the key to OUTAGE PREVENTION
Partial Discharge (PD)the key to OUTAGE PREVENTION
BECAUSE PD is a factor in 85% of MV substation insulation failures
PD measurement BUSINESS BENEFITS
• Outage prevention
• Improved reliability and safety
• Reduced maintenance costs
• Smarter replacement decisions
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
Partial Discharge (PD)the key to OUTAGE PREVENTION
switchgear failure switchyard failure
Partial Discharge (PD)the key to OUTAGE PREVENTION
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.
Void
GroundConductor
V withstand of C2 < applied field V withstand of C1&C3 > applied field
What is Partial Discharge (PD)?
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One effect of this flashover is a high frequency current pulse that travels through the capacitance of the insulation (C1 & C3)
HF CurrentPulse
C1 C2 C3
Products of Partial Discharge
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Partial discharge breakdown of insulation produces:
Light, Heat, Smell, Sound, Electromagnetic Waves, and an
HF Electric Current
+
Water
Nitric
AcidElectric
TEV
Partial Discharge (PD)
• 3.3kV to 69kV
• Indoor Metal clad switchgear cubicles
• Indoor and Outdoor Insulators
• Transformer Cable Boxes
Types of Switchgear
the key to OUTAGE PREVENTION
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
internal PD
Occurs in all types of insulation, including oil and gas
Partial Discharge (PD)the key to OUTAGE PREVENTION
Surface PD
Causes treeing and tracking
Partial Discharge (PD)the key to OUTAGE PREVENTION
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
INTERNAL DISCHARGETEV Detection
Internal Partial Discharge Effect 1(current pulse - TEV)
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HV BUSBAR
PARTIAL DISCHARGEJOINT/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
Internal Partial Discharge Effect 1(current pulse - TEV)
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HV BUSBAR
PARTIAL DISCHARGEJOINT/GASKET
HV BUSBAR
HIGH FREQUENCY
PULSE TO METALWORK VIA
CAPACITANCE OF INSULATOR
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
PULSE TRAVELS
VIA SKIN EFFECT
HV BUSBAR
EM WAVEEM
WAVE
PARTIAL DISCHARGEJOINT/GASKET
HV BUSBAR
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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
Phase to Phase Partial Discharge (current pulse – NO TEV)
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HV BUSBAR
PARTIAL DISCHARGEJOINT/GASKET
HV BUSBAR – Phase A
HIGH FREQUENCY
PULSE FROM PHASE TO ANOTHER.
NO CURRENT PULSE
ON METALWORK
No TEV reading
UltraTEV
HV BUSBAR – Phase B
HV BUSBAR – Phase C
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Internal Partial Discharge Overhead insulator (TEV)
PULSE TRAVELS
VIA SKIN EFFECT
TEV RESULTS DUE TO
IMPEDANCE OF GROUNDING
Insulator
Discharge
Conductor
UltraTEV
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Internal Partial Discharge Overhead insulator (EM Wave)
EM Wave
PD Hawk
TEV from PDEMI 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
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Probable Internal
No Internal Significant
Discharging
PossibleSurface Discharging
ProbableBackgroundInterference
Probable Floating Metal
Bad Conn
TEV Interpretation
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Background level
Above 10 dB Below 10 dB
Eliminate Background where possible and continue
TEV Level on switchgear
Within 10 dBof Background
More than 10 dBAbove background
No significantInternal Discharging
Pulses per cycle
Above 150 PPC1-50 PPC
ProbableInterference
TEV Level on switchgear
Pulses per cycle
More than 50 dB
Below 25
ProbableBad Connection
ProbableFloating Metal
Around 100 8-150 PPC
TEV Level on switchgear
< 20 dB > 20 dB
Probable internal Discharge
< 10 dB
No significant InternalDischarging
10 - 45 dB
Probable Surface Dischargeconfirm with Ultrasonic
Above 150 PPC
Example 1: Failure of Cast Resin CT
Long term erosion of
insulation leading to
flashover and failure
Cable Termination Screen Failure
Background Interference
A B C D E F
Battery
charger
Radio
mast
DC Light fitting
Mobile
phone
mast
HV OHL
Variable
speed
drive
Switchboard
Surface Discharge - Ultrasonic Detection
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
Cracks / contaminated surface
Carbonised tracking
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
Surface Discharge
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
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°C %RH Ultrasonic
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.
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
Surface Discharge Activity Detected by Ultrasonics
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
Moisture Ingress leading to surface tracking
Surface Discharge on 11kV Cast Resin Circuit Breaker Spouts
Surface Discharge Activity Detected by Ultrasonics
11kV CB Porcelain Spout
Fixed HV spout
(Porcelain)
CB Bushing (Resin)Film of sticky petroleum jelly
Remedial Action
Cleaned Off with dry lint free
wipes
Raychem
Sleeve
2mm
Crossed
Remedial Action
Replace the last
few metres of the
cable by putting in
a new joint
and termination
•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
Corrosion due to PD activity
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
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
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
Partial Discharge (PD)the key to OUTAGE PREVENTION
Detect
PD Techniques
surface/airgap: ultrasonic
internal: TEV
IDEAL FOR first pass surveys of surface and internal PD activity
UltraTEV Detector™
dual-sensor PD detection tool
TRAFFIC LIGHT display indicates PD levels
surface/airgap: ultrasonic
internal: TEV
UltraTEV Detector™
dual-sensor PD detection tool
ESSENTIAL personal safety device:
warns of dangerous PD activity in
working environment
substation entry working in substations
UltraTEV Detector™
dual-sensor PD detection tool
complete kit
• Easy to use
• Portable
• Rugged
features
• Fast
• Factory-calibrated for
accuracy
• Minimal training need
UltraTEV Detector™
dual-sensor PD detection tool
Partial Discharge (PD)the key to OUTAGE PREVENTION
MEASURE
PD techniques
•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
UltraTEV Plus+™
multi-functional Partial Discharge (PD) instrument
Provides two techniques to QUICKLY locate & measure surface and internal PD activity
surface/airgap: ultrasonic
internal: TEV
UltraTEV Plus+™
multi-functional Partial Discharge (PD) instrument
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
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
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
Ultrasonic Features
•Separately adjustable Gain and
Volume settings
•Immediate Red / Green
indication based on user
adjustable alarm threshold
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
Partial Discharge (PD)the key to OUTAGE PREVENTION
PD techniques
SURVEYS & LOCATES PD activity in all substation assets – including cables
surveys locates
UltraTEV Locator™
portable Partial Discharge (PD) investigation system
MEASURES & RECORDS PD activity in all substation assets – including cables
measures records
UltraTEV Locator™
portable Partial Discharge (PD) investigation system
PLUG-IN OPTIONS for greater versatility
RFCT cable sensor Ultrasonic Contact ProbeTM
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
UltraTEV Locator™
portable Partial Discharge (PD) investigation system
UltraTEV Locator™
portable Partial Discharge (PD) investigation system
complete kit
• Easy to use
• Portable
• Rugged
UltraTEV Locator™
portable Partial Discharge (PD) investigation system
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1
• 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
Cable Data Collector™
Partial Discharge (PD) detection in cables
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How It Works
Cable Data Collector™
Partial Discharge (PD) detection in cables
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3
• 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)
Cable Data Collector™
Partial Discharge (PD) detection in cables
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4
• 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
Cable Data Collector™
Partial Discharge (PD) detection in cables
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•The CableData™ Collector Solution consists of three components
• CableData™ Collector Instrument (left image)
• CableData™ Collector Software (center image)
• CableData™ Analysis Software (CDAS) (right image)
Cable Data Collector™
Partial Discharge (PD) detection in cables
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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
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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
• 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
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Powerful data analysis
Cable Data Collector™
Partial Discharge (PD) detection in cables
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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
SAFELY locates internal PD activity in open terminal switchgear
PD Emission
PD Hawk™
switchyard PD locator
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
business benefits
• Prevents costly failures
• Rapid return on investment
• Gathers valuable data on
asset condition
• Extends asset life
PD Hawk™
switchyard PD locator
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
SignalsdetectedIn this range
Signals out hereare rejected
Signals out hereare rejected
PD Hawk™
switchyard PD locator
Sweep the Hawk around substation while rotating 90 degrees to compensate for polarization
PD Hawk™
switchyard PD locator
Safely approach the locations with highest levels and aim at specific assets
PD Hawk™
switchyard PD locator
Record or download data for reporting or comparison with future readings
Android Tablet/Phone App
PD Hawk™
switchyard PD locator
complete kit
• Easy to use
• Portable
• Rugged
PD Hawk™
switchyard PD locator
Partial Discharge (PD)the key to OUTAGE PREVENTION
PD techniques
24/7 MONITORING of substation assets
• Detection
• Location
• Measurement
• Recording
• Communication
• Alarms
• Analysis
• Interpretation
• Reports
UltraTEV Monitor™
substation monitoring and alarm system
UltraTEV Monitor
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.
Example Node
Power &
Status LEDs
Ultraso
nic
Inputs
Cable
PD
Input
TEV
Input
Aux
Power
Input
Communications
Test and Reset
Buttons
Sensor Status
LEDs
Example Sensors
External TEVSensor
Antenna (for cancelling background noise)
EnvironmentalSensor
UltrasonicSensor
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
– 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.
Severit
y
Magnitude Source A
Precedence Source A Precedence Source B
Magnitude Source B
Single Discharge Sites
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Instance Profile – Data Selection
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Select Monitoring Time Period
Select the generated period
Summary Report
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Summary Report