HIGH VOLTAGE SPECIALISTS — GRID STAT ION LEVEL
Testing & Diagnostic Services
Comprehensive field testing, commissioning, and fault diagnostics for HV/MV power infrastructure across Pakistan’s industrial and utility sector — delivered by certified engineers with calibrated equipment.
COMPLIANT STANDARDS
- IEC 62271 (SF6 Equipment)
- IEC 60076 / IEEE C57 (Transformers)
- IEC 60502 (HV Cables)
- IEC 60255 / IEEE C37 (Protection Relays)
- EPA SF6 Regulations
Transformer Testing
20+
TEST CATEGORIE
IEC 60076 / IEEE C57
- Full diagnostic and acceptance testing for power transformers at grid and transmission substations — from winding resistance to DGA and SFRA analysis. All tests conform to IEC 60076 / IEEE C57 standards.
TEST 01
WINDING
Winding Resistance Test
Measures DC resistance of transformer
windings to detect open circuits, loose
connections, broken strands, and contact defects in tap changers. Verifies balanced phase resistance.
TEST 02
WINDING
Turns Ratio Test (TTR)
Verifies the actual turns ratio between
primary and secondary windings against nameplate data. Identifies shorted turns,winding faults, and tap changer position errors.
TEST 03
DIAGNOTIC
Insulation Resistance Test (IR)
Evaluates transformer winding insulation
quality using a high-voltage DC
megohmmeter. Detects moisture ingress,contamination, and insulation degradation before catastrophic failure.
TEST 04
DIAGNOSTIC
Polarization Index (PI) Test
Assesses insulation condition by
comparing megohm readings at 1 and 10
minutes. A low PI value indicates wet or
contaminated insulation, supporting critical
go/no-go decisions.
TEST 05
DIAGNOSTIC
Dielectric Absorption Ratio (DAR)
Measures dielectric dissipation factor to
assess aging, moisture absorption, and
contamination for predictive maintenance
and condition-based assessment.
TEST 06
DIAGNOSTIC
Power Factor / Tan Delta Test
Measures dielectric loss angle (tan delta)to quantify insulation aging, moisture
content, and contamination. A high power factor reading signals deteriorating
insulation.
TEST 07
DIAGNOSTIC
SFRA — Sweep Frequency Response Analysis
Detects mechanical deformations and
winding displacement by comparing
frequency response signatures. Used after transportation, short-circuit events, or
seismic activity.
TEST 08
OIL
Oil Dielectric Strength Test
Determines breakdown voltage of
transformer insulating oil to confirm it can withstand operating electrical stresses.
Low dielectric strength indicates moisture or aging byproducts.
TEST 09
OIL
Oil Dissolved Gas Analysis (DGA)
Analyzes gases dissolved in transformer oil to identify early-stage thermal and
electrical faults such as partial discharge,arcing, and overheating. The most
powerful predictive maintenance tool.
TEST 10
OIL
Oil Moisture Content Test
Verifies correct installation of crossbonding links and sheath bonding
conductors to suppress induced sheath
voltages and reduce circulating currents
TEST 11
TESTING
Short Circuit / Impedance Test
Measures percentage impedance voltage and load losses at rated current, validating nameplate data. Impedance values are
critical for protection relay coordination
and fault current calculations.
TEST 12
TESTING
No-Load Loss Test (Open Circuit)
Measures core losses (iron losses) when energized at rated voltage with no
connected load. Elevated no-load losses indicate core lamination damage or
shorted joints.
TEST 13
PROTECTION
Buchholz Relay Test
Functionally tests the Buchholz relay to ensure it correctly detects gas
accumulation and oil surge caused by
internal faults. Essential for fast
transformer tripping and damage
limitation.
TEST 14
TESTING
Applied Voltage (Hi-Pot)Test
Applies high AC voltage between windings and ground to verify dielectric withstand
strength. Confirms insulation can safely
handle transient overvoltages in grid
operating conditions.
TEST 15
TESTING
Induced Voltage Test
Tests insulation between turns and layers within the same winding by inducing twice
the rated voltage at elevated frequency.
Detects turn-to-turn weaknesses not found by applied voltage testing.
TEST 16
TESTING
Temperature Rise Test
Validates that winding and oil
temperatures remain within permissible
limits under rated load. Confirms cooling
system effectiveness and compliance with IEC/IEEE thermal standards.
TEST 17
PROTECTION
Tap Changer (OLTC)Functional Test
Verifies correct operation of On-Load Tap Changer across all tap positions, checking transition resistance, contact timing, and
drive mechanism performance.
TEST 18
DIAGNOSTIC
Bushing Power Factor Test
Measures capacitance and tan delta of
transformer bushings to detect moisture,oil leaks, partial discharge, and insulation aging. Faulty bushings are a leading
cause of transformer explosions.
TEST 19
TESTING
CT Tap Voltage Ratio Test
Confirms voltage ratio and polarity of CT
taps integrated into the power transformer,ensuring accurate metering and protection relay inputs. Ratio errors can cause
incorrect billing.
TEST 20
PROTECTION
Grounding / Earthing Continuity Test
Verifies electrical continuity and resistance of the transformer tank, neutral, and all
metal enclosures to the station earth grid.Essential for personnel safety and reliable fault current dissipation.
Relay Penal Testing
16+
TEST CATEGORIE
IEC / IEEE COMPLAINT
- Comprehensive protection testing, calibration, and commissioning for relay panels across HV/MV substations. IEC / IEEE compliant. Calibrated test equipment and detailed reports provided
TEST 01
COMMISIONING
Protective Relay Calibration
Verifies and adjusts relay settings to
ensure accurate trip thresholds and time
delays in grid station protection systems,
confirming each relay operates precisely
within defined parameters.
TEST 02
TESTING
Insulation Resistance (Megger) Test
Measures dielectric integrity of relay panel
wiring and control cables using a highvoltage DC source, detecting moisture
ingress, insulation degradation, and
potential ground faults.
TEST 03
TESTING
Contact Resistance Test
Measures ohmic resistance across relay
contacts and terminal connections.
Elevated values indicate oxidation or
mechanical wear that can cause delayed
or failed tripping during fault conditions.
TEST 04
TESTING
Functional / Operational Test
Verifies complete end-to-end operation of
relay panels by simulating real fault and
control scenarios, confirming all relays,
contactors, indicators, alarms, and trip
outputs respond correctly.
TEST 05
COMMISIONING
Polarity Check
Verifies correct phasing and directional
orientation of CT and PT connections
feeding relay panels, preventing
directional relay maloperation and
unwanted tripping during commissioning.
TEST 06
TESTING
Secondary Injection Test
Applies controlled test currents and
voltages directly to relay input terminals to
verify pickup values, time-current
characteristics, and trip functions without
energizing primary circuits.
TEST 07
TESTING
Primary Injection Test
Applies high-current signals through actual
primary conductors and CTs to verify the
complete protection circuit from CT
primary to relay trip output under realistic
fault conditions.
TEST 08
TESTING
Overcurrent Relay TesT
Verifies that phase and earth overcurrent
relays operate at set pickup currents
within defined IDMT or definite time
characteristic curves for proper system
coordination.
TEST 09
TESTING
Differential Relay Test
Checks transformer and busbar differential
protection relays to confirm correct
detection of internal faults, restraint
characteristics, and harmonic blocking
features.
TEST 10
TESTING
Earth Fault Relay Test
Verifies sensitivity and operating time of
relays designed to detect single-phase-toground faults, confirming correct pickup
thresholds for core balance and residual
protection.
TEST 11
TESTING
Distance / Impedance Relay Test
Evaluates the relay’s ability to measure
faulted line impedance and trip within
correct zone boundaries (Z1, Z2, Z3),
validating reach settings, directional
characteristics, and operating times.
TEST 12
INSPECTION
Auto-Reclose Relay Test
Verifies automatic reclosing sequences
including dead time intervals, reclaim
times, reclosing attempts, and lock-out
conditions to improve system availability
after transient faults.
TEST 13
MEASUREMENT
Burden Test
Measures total VA load imposed on CT
and PT secondaries by connected relay
panels and meters, ensuring burden stays
within rated limits to prevent CT saturation
and maintain accuracy
TEST 14
TESTING
High Voltage Withstand Test (HIPOT)
Verifies that current transformers provide
the correct turns ratio and current direction
to connected relays and meters,
fundamental for preventing differential
relay maloperation.
TEST 15
INSPECTION
PT Ratio & Polarity Test
Confirms that potential transformers
deliver correct secondary voltage
magnitude and phase relationship, critical
for distance relay reach accuracy and
directional relay discrimination.
TEST 16
TESTING
Logic / Scheme Test
Validates complete protection and control
logic including interlocks, blocking signals,tripping matrices, and SCADA interface
functions for dependable operation under all fault scenarios.
HV Cable Testing
15+
TEST CATEGORIE
IEC / IEEE COMPLAINT
- Comprehensive diagnostics, safety testing, and commissioning for medium and high voltage cable infrastructure.Certified engineers available for on-site assessments, pre-commissioning, and emergency fault location.
TEST 01
TESTING
Insulation Resistance (Megger) Test
Measures electrical resistance of cable
insulation using high-voltage DC,
identifying moisture ingress, degradation,and potential failure points in HV cables.
TEST 02
TESTING
Hi-Pot AC Test (VLF)
Measures dielectric integrity of relay panel
wiring and control cables using a highvoltage DC source, detecting moisture
ingress, insulation degradation, and
potential ground faults.
TEST 03
TESTING
Hi-Pot DC Test
DC high voltage stress-testing for defects,water trees, and aging deterioration —
widely used for pre-commissioning and
maintenance of MV/HV cables.
TEST 04
DIAGNOSTIC
Partial Discharge (PD) Test
Detects and locates harmful electrical
discharges within insulation voids, joints,and terminations — early warning of
defects before catastrophic failure.
TEST 05
MEASUREMENT
Tan Delta (Dissipation Factor) Test
Measures dielectric dissipation factor to
assess aging, moisture absorption, and
contamination for predictive maintenance and condition-based assessment.
TEST 06
TESTING
Cable Continuity Test
Verifies each conductor is electrically
continuous end-to-end with no breaks or open circuits, ensuring safe power
transmission before energization.
TEST 07
TESTING
Cable Polarity Test
Confirms correct phase identification and polarity at both ends, preventing
dangerous phase mismatches during grid station cable installation.
TEST 08
TESTING
Cable Sheath Integrity Test
Applies DC voltage between metallic
sheath and earth to detect pinholes or breaches in the outer protective jacket,safeguarding against ground faults.
TEST 09
DIAGNOSTIC
Cable Fault Location (TDR)
Uses Time Domain Reflectometry to
precisely locate short circuits, open
circuits, and insulation breakdown —
minimizing outage time and excavation scope.
TEST 10
TESTING
Cross-Bonding / Sheath Bonding Test
Verifies sensitivity and operating time of
relays designed to detect single-phase-toground faults, confirming correct pickup
thresholds for core balance and residual
protection.
TEST 11
MEASUREMENT
Loop Resistance Test
Evaluates the relay’s ability to measure
faulted line impedance and trip within
correct zone boundaries (Z1, Z2, Z3),
validating reach settings, directional
characteristics, and operating times.
TEST 12
INSPECTION
Thermal Imaging (Infrared)Test
Non-invasive infrared inspection to detect abnormal heat at cable joints,
terminations, and switchgear caused by
loose contacts or insulation degradation.
TEST 13
MEASUREMENT
Capacitance Measurement Test
Measures capacitance per unit length to
verify cable construction, calculate
charging current, and validate parameters for protection relay settings.
TEST 14
TESTING
High Voltage Withstand Test (HIPOT)
Subjects cable insulation to sustained high voltage to confirm it can withstand
operating and overvoltage conditions —
the final acceptance test for new cables.
TEST 15
INSPECTION
Cable Termination & Joint Inspection
Visual and electrical inspection of
terminations and joints to detect improper
installation, tracking, mechanical damage,or partial discharge activity.
SF6 Gas Testing
15+4
TEST CATEGORIES
IEC 62271 / EPA
- Comprehensive SF6 diagnostics, leak detection, and decomposition analysis for HV circuit breakers and GIS equipment. IEC 62271 and EPA SF6 regulation compliant.
TEST 01
TESTING
Leak Detection (Tightness Test)
Verifies the gas-tight integrity of SF6 circuit breakers and GIS
equipment to prevent hazardous gas leaks, ensure compliance with IEC 62271 and EPA SF6 regulations, and maintain optimal dielectric and arc-quenching performance.
TEST 02
MEASUREMENT
Purity / Concentration Test
Measures SF6 gas concentration (minimum 97% purity) inside circuit breaker interrupter chambers to confirm sufficient dielectric strength
and arc-interruption capability, preventing insulation failure and
unplanned outages.
TEST 03
MEASUREMENT
Moisture / Dew Point Content Test
Determines water vapor content (dew point) within SF6 gas
compartments to prevent internal condensation, hydrolysis of SF6,and corrosion of live parts — keeping moisture below IEC-specified limits.
TEST 04
DIAGNOSTIC
Decomposition Product Analysis
Identifies and quantifies toxic byproducts (SO2, H2S, HF, SOF2,
SO2F2) produced when SF6 is exposed to high-energy arcing.
Enables early diagnosis of internal electrical faults and guides safe maintenance decisions.
