Testing Services
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At SRESTA, we offer a wide range of high-precision electrical testing services to ensure the integrity, safety, and performance of your power systems. Our expert engineers and certified technicians utilize advanced diagnostic equipment to detect faults, verify functionality, and ensure your equipment operates reliably under real-world conditions
Our testing services include:
Protective Relaying Systems Testing
Protective relays must be an essential shield in electrical systems. They observe for any aberrant conditions including high currents, short circuits or power quality/storage faults. If issues like this are detected, the device will automatically isolate effected sections to minimise damage and preserve the structural integrity of a system.
What we do:
Perform secondary injection tests to test relays under actual fault conditions
Assess Coordination and Trip Characteristics for timely selective fault isolation.
Perform relay functional, inspect and calibrate the relay settings such as trip point thresholds, response timing
Test relay performance including digital and numerical relays within relay test equipment by using special relay testing equipment
Conduct relay trip response test under voltage/frequency changes, earth fault events and differential protection incidents.
Power Transformer Testing (up to 400KV)
Transformers are critical to the electrical grid, they provide efficient voltage transformation for power transmission and distribution. Insulation tests are a must as periodic maintenance to validate insulation strength and internal condition for high voltage applications.
What we do:
Insulation Resistance (IR) Testing – Insulates checking of windings to ground and tightness from the applied voltage.
Prerequisite Verify Transformer Turns Ratio (TTR) — Determines that the voltage ratios are accurate and finds wrong winding connections
Identifies problems such as loose connections and slight winding faults — Winding Resistance Measurement.
Phase Critique: Tests voltage phase relations and checks for the right sequence of the transformer.
Dielectric loss (Tan Delta) – Measure the quality of the insulation and its aging.
Magnetizing Current Analysis: Test your core condition and determine partial solaturation issues.
Oil Breakdown Voltage (BDV, applicable) – Assesses insulation of transformer oil.
Generator Testing (up to 500MW)
Generators are central components in almost every power generation system, and their efficiency is determinant for plant performance.
What we do:
Inspection of Insulation Resistance – Stator wringings among frame and ground for leakage and inter winding short. Testing
Generator Winding Resistance Testing: It can identify imbalances, defective joints or damaged turns in the stator.
PI and DAR testing-Thermally characterize how insulation behaves when it is subjected to heat to assist differentiate moisture or contamination readings.
Identify dielectric loss as aging or deterioration of insulation by means of Tan Delta Measurement.
High-performance Testing (Hi-Pot; AC/DC) – confirms the electrical strength of winding insulation under high voltage stress.
In-Service Tests — General functionality tests including, synchronization, excitation response and voltage build-up.
Machine Temperature Monitoring at Load -Measuring temperature rise to assure that the machine remains cool enough when in service.
AC & DC Motor Testing (up to 33KV)
Every industrial process, at the end of it all has a motor in it Motors Whether Integrated AC Induction Unit or DC motor degradation leads to mechanical failure, expense downtime and safety hazards.
What we do:
Insulation Resistance Testing – Inspect condition of motor winding insulation versus earth to cure current leakage in the insulation.
Inspection of the Winding Resistance is to detect a shorted turn, poor joint or unbalance windings.
Insulation Analysis — Provides a view of the dielectrics ability in resisting aging, moisture and contamination per PI and DAR
No-load/Load Testing (Performance Testing) Compares the actual performance of the motor to its rated specifications.
Vibration Testing: Determines mechanical faults such as axial misalignment of shaft, rotor imbalance or bearing failure.
Measure HVAC Loads — Takes a look at the current and voltage on each phase looking for things such imbalances, overloads.
Infrared Thermographic: Identifies hot-spots and overheating in real-time for preventive maintenance.
Switchgear Testing (up to 33KV)
Switchgears performs the management, defense and isolation of electrical circuits in a power system.
What we do:
Inspection testing — This does an insulation performance for each phase and also phases to ground, insures that she operates safely.
Contact/Connectivity Degradation Analysis — This inspects the resistance at the interface, able to detect fall-out that results in heat generation.
Integrated Interlock & Mechanism Testing — Functions to confirm that safety interlocks do their job and mechanical movements can perform smoothly.
Breaker Test:- Used to measure time between open/close of breaker for industrial practices, insures fault nodes are cleared within the limited time.
Primary Injection Testing: to stress tripping a relay and/or breaker with actual current required for the relay/breaker set.
Thermal scanning — RADIALLY Integrated IR imaging SHOULD Point out abnormal heat zones of proceeding from connections/joints to busbar.
Mechanical Survey — Checks state of moving parts, arc cutout and operating cam/Hydraulic Linkages.
CT and CVT Testing (up to 400KV)
Current Transformers (CTs) and Capacitive Voltage Transformers (CVTs) play a key role in high-voltage power systems. They help to provide smaller signals for metering and protection. Getting these signals right is crucial for protective relays, energy meters, and control units to work properly.
What we do:
- Ratio and Polarity Verification, we check that the transformer steps down current or voltage correctly and keeps the phase in line.
- Saturation/Excitation Testing, we look at how CTs perform with different current levels to see their classification and linear range. –
- Insulation Testing, we measure the resistance between windings and the ground to find any wear or moisture issues.
- Tan Delta and Capacitance Testing (CVTs), This helps us assess internal insulation losses and the health of the dielectric.
- Burden Testing, we make sure the connected loads on the secondary side don’t exceed the limits, keeping accuracy intact.
- Secondary Injection Simulation, this mimics real fault conditions to check how the output behaves and how well the protection responds.
Battery Capacity Testing (All Types)
Power backup and industrial battery banks play a key role in keeping the lights on when the grid goes down or during emergency shutoffs. As batteries get older, they often lose their punch and can’t deliver full power. Regular checks make sure they’ll work when you need them most.
What we do:
- Controlled Discharge Tests – We run the battery under a fake load to see how many amp-hours (Ah) it puts out.
- Internal Resistance Checks, we spot weak cells or units that might fail by looking at their resistance levels.
- Voltage Tracking for Each Cell, we keep an eye on how each cell acts during charging and discharging.
- Heat Monitoring we look for too much heat that could make the battery less efficient or wear out faster.
- Physical Checks & Cleaning ,we look for leaks, rust, or damage on the batteries and clean the terminals to keep them connected.
Partner with SRESTA for Reliable Electrical Solutions
At SRESTA, we are committed to delivering trusted expertise in high-voltage electrical testing, commissioning, and maintenance services. With years of hands-on experience and industry-recognized certifications, we specialize in ensuring that your electrical systems function safely, efficiently, and without interruption. Our services are built on a foundation of precision, reliability, and compliance with the latest industry standards. Whether it’s a critical substation, a power plant, or a large industrial installation, we approach every project with meticulous attention to detail and a commitment to long-term performance.
We understand that electrical infrastructure is the backbone of every operation, which is why we provide tailored solutions that address both current needs and future challenges. From detailed equipment diagnostics and fault analysis to system upgrades and preventive maintenance, our team is equipped with advanced tools and a problem-solving mindset. We don’t just test and maintain—we partner with you to improve operational efficiency, reduce downtime, and extend the life of your critical assets.
Reach out to us today—let’s power your success together.