Quality Assurance is a field which has gained much significance since solution providers adopted the domain as a Unique Selling Proposition (USP). The difference between a good solution and a great solution is essentially the quality that is delivered in the process. Considering the Total Cost of Ownership (TCO), it is essential from a business stand point, to ensure compliance with international standards during the deployment rather than investing in the rectification of snags later.
This article will cover some basics of QA/QC pertaining to Electrical Power Infrastructure which may serve as a key for Quality Inspectors. It must be noted here that the contents covered in this article mainly pertain to tests which may be performed at the deployment site during Site Acceptance Testing (SAT), without requiring highly sophisticated equipment.
1. Quality Control for Power Cables:
Deployment of Power Cables must be aligned with IEC 60502, IEC 540, IEC 60228, IEC 60332-1, IEC 60332-3, IEC 60227, BS EN 50266, BS 6004, BS 6346, BS 7846 and BS 7889.
The following actions, inter alia, must be performed while testing:
Verify the List of Material as per the approved Design Submittal.
Verify the Gauge and the number of cores in the cable.
Verify the color coding of the cable as per project specifications and also ensure that the length marking is given at minimum 1-meter spacing.
Perform Continuity Test to ascertain the integrity of the Conductor.
Perform Insulation Resistance test to ascertain the integrity of the Insulation.
At any point in the deployment, there should be no sharp bends (90 degrees).
If Power Cables and Communication Cables and running in parallel, a minimum distance of 8 inches must be maintained between both cable trays. Properly covered trays must be used to shield the communication cables from Electromagnetic effects.
2. Quality Control for Distribution Transformers:
Deployment of Distribution Transformers must be aligned with IEC 60076-1,2,3, IEC 60076-3-1, 60076-5 and 60296.
The following actions, inter alia, must be performed while testing:
Verify the List of Material as per the approved Design Submittal.
Verify the dimensions of the Transformer including length, width and depth.
Verify the provision of allied accessories including Oil Drain Plug, Bi-directional rollers, Lifting Lugs, Dial type thermometer, Rating plate, Pressure relieve safety value.
Verify the provision of Factory Acceptance tests including Turn Ratio, Power Frequency, Open Circuit, Short Circuit, Dielectric strength and Paint thickness.
Verify the color of the silica gel, if it has turned pink then dehydration is required.
Verify the distance between two bushings of the Transformer, it should not be less than 6 inches.
Connect the Bucholz relay with the annunciator provided in MV panel and verify the operations by manually twisting the dial until an alarm is generated on the panel.
Verify the operation of the Transformer Winding Temperature Thermometer by integrating it with the MV panel and generating a false signal.
Verify the paint thickness on the body of the Transformer by using Picometer.
Obtain a sample of the oil from the drain of the Transformer and perform di electric testing on site to ensure the integrity of the insulating oil.
3. Quality Control for HT & LT Switchgear:
Deployment of HT Switchgear must be aligned with IEC 62271-100, 62271-102, 62271-103, 62271-200, 60694, 60044-1, 60044-2, 6005-1,2,3,5 & 8 along with IEC 60099-4. Deployment of LT Switchgear must be aligned with IEC 60947-3, 60947-2, 60831, 60073, BS EN 60529, IEC 60044-1, 60044-2, 60051-1, 2,3,5 & 7 along with BS 88.
The following actions, inter alia, must be performed while testing:
Verify the List of Material as per the approved Design Submittal.
Verify the dimensions of the Panel including length, width and depth.
Perform Visual checks including Earthing of the panel, labelling of components, mechanical operation and interlocking.
Perform Electrical checks including Tripping mechanism, working of Indications/Alarms, Electrical operation and Interlocking.
Perform Insulation Resistance test on the Bus bars to ensure there is no short circuiting.
Perform Phase rotation test.
Verify the paint thickness on the body of the panel by using Picometer.
For the MV Panel, use the test block and connect a Current Injector to simulate fault signals on the relay to verify the Short Circuit, Over Current and Earth Fault features.
Verify the control connections between the transformer Bucholz relay and the annunciator installed in the MV panel.
Calibrate the Energy Meter installed on the MV panel based on the CT ratio.
Verify the operation of the anti-condensation heaters installed in the body of the panel.
4. Quality Control for Low Voltage Diesel Generators:
Deployment of Low Voltage Diesel Generators must be aligned with BS 5514, BS 4999, BS 5000-99 and IEC 34.
The following actions must be performed while testing:
Verify the List of Material as per the approved Design Submittal.
Verify the dimensions of the Generator including length, width and depth.
Perform Visual Checks including verification of Earthing, installation of Vibration Isolators, ducting of generator exhaust and proper termination of power cables.
Verify that the Engine Oil, Coolant and all allied filters are in good condition.
Check Engine Mounts, Air Intake system, Belt tension and its condition, Coolant level, Battery electrolyte level, Battery charger, Engine speed and load per phase.
Connect the Control Unit of the Generator with the allied software and generate dummy faults to check the tripping function.
Ensure the connection of the water jacket heaters with the terminals provided in the control unit.
Connect an appropriate dummy load bank with the generator and load the generator at 25% for 15 minutes, ramp it up to 50% for 45 minutes, 75% for 60 minutes, 90% for 20 minutes, 100% for 20 minutes and 110% for 10 minutes.
“The difference between a good solution and a great solution is essentially the quality that is delivered in the process.”
– Speak to the leading Power Sector and Infrastructure Expert who wrote this article
Expert Bio:
Expert is a Second Generation Power Sector Specialist with 7 years of diverse experience in Manufacturing, Construction, Consultancy, Telecommunication Power Infrastructure, Technical Sales & Strategic Energy Policy Regulation.
Key roles and experiences include:
– Technical assistant manager to Ministry of Energy where he worked on commercial and governing codes for energy markets and managed market operations.
– CME Design Analyst where he designed and deployed a number of infrastructure systems for data centers from electrical and cooling infrastructure to fire suppression systems.
– Worked as an electrical engineer in a global urban infrastructure planning firm where he was in charge of power infrastructure support for data centers and communication sites.
Expert has extended knowledge on:
– Unconventional Energy (Bio Energy, Nuclear, Hydro, Geothermal, Tidal)
– Energy Management, Transmission, DSR, Smartgrids, Microgrids
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The Expert’s geographic area of expertise is predominantly in Asia-Pacific and Pakistan, with a heavy focus on electrical engineering and power sector roles.
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