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.

55+

TEST CATEGORIES

4

SERVICE DIVISIONS

24/7

EMERGENCY SUPPORT

2011

EST. LAHORE

COMPLIANT STANDARDS

Transformer Testing

20+

TEST CATEGORIE
IEC 60076 / IEEE C57

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

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

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

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.