Friday, 4 October 2024

Various electrical laboratory test and purpose

Equipment name- LT & MV Power Cables, Go Switches, AB Switches, porcelain Insulator, Current Transformer, Voltage transformer. Test Name 
  Partial discharge test – Partial discharge measurement of cables is very important as it gives an indication of expected life of the cable. When a cable is subjected to high voltage and if there is a void in the cable, the void breaks down and a discharge takes place. 
Impulse withstands voltage test- The test samples are subjected to positive and negative impulse voltage of magnitude as specified in specification; the sample should withstand without any damage. 
Power frequency withstand voltage test (HVT)- electrical products are tested for power frequency A.C. and D.C. voltages. The test voltage is applied on the sample for specified time. the sample is said to have withstood the test if no insulation failure/ flashover /puncture takes place during specified time duration. Dielectric power factor test (Tan Delta Test) -the healthiness of electrical samples can be determined by the ratio of the resistive component to the capacitive component. For good samples, this ratio would be quite low. This ratio is commonly known as tan δ or tan delta 
Hot Set Test - A Measure to Determine the Amount of Cross-Linking Achieved, for Cured Materials such as XLPE and Elastomers Hot Air Aging Test- The hot air aging test is one of the main test methods for evaluating polymer materials and studying the aging resistance of polymer materials. It is usually carried out in a constant temperature blast drying test chamber.
 Electrical Resistance- Electrical Resistance is an electrical quantity that measures how the device or material reduces the electric current flow through it. The resistance is measured in units of ohms (Ω). Tensile Strength: Tensile strength is usually measured as the amount of force in newtons per square mm or megapascals (MPa) required to pull a specimen to the point of material failure. This test is accomplished by placing a dumbbell shaped specimen into the grips, or jaws. 
Elongation – Elongation is measured by applying tensile force, or stretching the material in the same manner as described previously, and determining the change in length from original. Elongation is expressed as a percentage of the original length. Ultimate elongation is the percentage change in length from original to rupture.
 Thermal stability – tests are conducted on PVC materials in order to determine the rate of thermal degradation at elevated temperatures. 
Power Frequency Wet Voltage Withstand Test -The test voltage applied to the samples is the specified value of the wet power frequency withstand voltage adjusted for atmospheric condition at the time of test.
 Water Absorption – 
 a) This test is done to ascertain the quantity of water absorbed when the insulation or sheath of cable laid underground comes into contact with water. 
 b) Loss of mass is the evaluation of loss of plasticisers and lubricants due to volatilisation during heating. 
Shrinkage Test – Cable testing for shrinkage is designed to check if the insulation material will shrink back whilst in service Heat Shock Test – Replicates the stress of bending and heating on the cable to check for any failure as evidenced by cracks appearing in the materials Hot deformation test – Thermoplastics tend to deform under high temperatures and small damage during movement or under installation to cable, can cause a puncture or cut of insulation Cold bend and cold impact testing - This method determines the resistance to impact or shock of the thermoplastic and elastomeric insulation or sheath at low temp 
Insulation Resistance (IR) test- insulation resistance test measures the total resistance between any two points separated by electrical insulation 
Bending test - bending tensile test) is a method of testing materials for their bending strength. Flammability test - Flammability testing determines how easily a material or finished product will ignite or burn when exposed to or used near fire or heat.
electrical laboratory test
Heat cycle test - The test to confirm the effect on power supply caused by the repetition of temperature change. 
ASTM G154 _ (UV Test) ASTM G154 - testing uses fluorescent light sources that can simulate UVA or UVB. This technique is used to evaluate the impact of UV exposure on a product’s mechanical properties 
ASTM G53 (UV Test)- This practice covers the basic principles and operating procedures for using fluorescent ultraviolet (UV) and condensation apparatus to simulate the deterioration caused by sunlight and water as rain or dew. This test covers the technique to confirm the thickness, diameter of sample, height, width & length conform to relative specification requirements. 
Test Method for Density of Smoke or ASTM D2843-22- This test method serves to determine the extent to which plastic materials are likely to smoke under conditions of active burning and decomposition in the presence of flame. 
Halogen Acid Gas Evolution- The test is to determine the amount of halogen acid gases that are created when cable insulation and sheathing compounds are burned 
Oxygen Index with Temperature Index - To determine the minimum percentage of Oxygen required to support flame combustion of a material at Room Temperature or at a Higher Temperature. (Up to 400 deg. C) 
 Torsion test -The purpose of a torsion test is to determine the behaviour a material or test sample exhibits when twisted or under torsional forces as a result of applied. Melt Flow Index, (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer. 
Carbon Black Content -To determine the average of carbon black content especially in polyethylene materials by pyrolysis method, like plastic pipes, films, sheets, cables Wrapping Test– The wrapping test is a ductility test which is employed to evaluate the ability of metallic wire to undergo plastic deformation during wrapping. 
Carbon Black Dispersion- This test method is used to determine the average carbon black dispersion in materials like Films, Plastic Pipes, Cables, Sheets. 
Stress strain Test Stress-Strain Diagram expresses a relationship between a load applied to a material and the deformation of the material. 
Source: Ghaziabad Testing Laboratories Pvt. Ltd

Sunday, 25 August 2024

Substation audit questionnaire

Substation internal audit should be done yearly basis. It is advisable to have a checklist and to be audited on regular interval. Good ambience will have better operational facility and long life of substation equipment.
1. Is authorized person list are updated? 
2. Is (SLD) single line diagram is updated? 
3. Is insulation mats are laid in front of and back to all panels? 
4. Is SOP standard operating procedure is updated? 
5. FLP light, EX fan, Detector and shower are installed in battery bank? 
6. Civil job of battery banks including eye shower, mirror, drain pipe, water availability, wash basis,             door lock, floor cleaning. 
 7. Is Substation door/ window/ventilator glasses broken &closing issue are rectified?
 8. Is there any false ceiling/flooring abnormalities? 
9. Is Substation lighting sufficient
10. Is Sprinkler system status updated? 
11. Any issue pertaining to Sprinkler/Deluge system bilingual SOP preparation and flex board printing         and installation- 
12. Is battery bank Do’s and Don’ts board provided ? 
13. Is DC lighting report available? 
14. Is Emergency handling scenario handbook available? 
15. Is TR yard free from vegetation, get locked. 
16. Is Scraps/spare materials dumped in substation and cable cellar removed? 
17. Is Substation roof leakage/water proofing job completed? 
18. Is Operator/shift in-charge log book signing checked regularly? 
19. is locking of Substation door /TR yard gate wherever missing? 
20. Is hazardous area classification displayed in manned location? 
21. Is ARC suit availability in manned locations checked? 
22. Is Splash suit in manned locations for battery bank job available? 
23. Is PPEs (HT/LT Hand gloves, Discharged rod, HT tester) available in manned location? 
 24. Is measuring tools calibrated? 
25. Is fire Extinguisher placement done at marked area ? 
26. Is status of Earth pit value and condition report available? 
27. Is flex boards of SLD, Shock treatment chart, Do’s & Don’ts, physical layout, Important Telephone         number displayed? 
28. Is any deviation in LOTO audit available?
29. Is Breaker lifting trolley testing report available? 
30. Is missing Sand/fire bucket, Sand filling done regularly? 
31. Is substation floor/TR yard cleaning done regularly? 
32. Is pressurization blower available, manometer provided? 
33. Is danger plates provided as voltage grade? 
34. Is danger Sticker on HT/LT panels in all substations provided?

Saturday, 17 August 2024

Possible cause of electrical failure

Due to the gap or deviation during the electrical operation and maintenance electrical failure takes places and sometimes it becomes so fatal.
 a) Safety
1) Not using PPE
possible cause of electrical failure 
2) Poor lighting 
 3) In/exit path missing
 4) Using non-standard tools 
5) Not using LOTO
 6) Wrong tag marking 
7) In sufficient fire detector, fire extinguisher 8) Improper SOP for energization/de-energization 

  b) Monitoring issue 
 9) Irregularity in in taking reading 
 10) Relay failure
 11) Irregularity in PM
 12) Time coordination with up stream
 13) Setting coordination with up stream 
14) Numerous alarm 
15) Irregularity in in taking reading of UPS, Battery charger 
16) High temperature in VFD/UPS room 

  c) Marking on panel
17) Feeder cubical name 
 18) Rating 19) Fuse rating 
20) Cable size 
 21) Special marking 

  d) Functional 
22) non availability of emergency light for power restoration 
 23) Auto failure of bus coupler 
 24) Spare short fall 
 25) Non availability of testing equipment 
 26) ill weather 
27) poor maintenance

  e) Fire Hazard 
 28) flammable material in cable cellar 
 29) Non FLP equipment in battery room
 30) Improper spacing of fire extinguisher 
 31) Hydrocarbon ingress in substation 
 32) Failure of insulation

  f) Furious tripping 
 33) Wrong relay setting 
 34) Wrong operation 
 35) Wrong sequence of operation 
 36) Wrong control circuit 
 37) Breaker failure 
 38) Poor scheme 
 39) Poor design 

  g) Flashover 
 40) Failure of end termination 4
1) Lizard entry
 42) Unwanted light on at night 
 43) Aging of equipment 
 44) CT/PT failure 
 45) Water ingress in JB/DB 
 46) Rodent entry
 47) Moisture ingress
 48) Poor ventilation 
 49) Fire in capacitor of AC 

  h) Knowledge gap 
 50) Lack of training 
 51) Lack of knowledge 
 52) Improper monitoring

Sunday, 28 July 2024

Moisture, humidity, reliability and electrical safety

Moisture, humidity is a great enemy for electrical power continuity and reliability. Excess moisture can cause: • Short Circuits: Moisture prepares a platform as conductive pathways, increasing the risk of short circuits and potential fire and a challenge for electrical safety. • Corrosion: maximum electrical components are susceptible to rust and oxidation, leading to malfunctions and equipment failure. This happens frequently in coastal area or where rainy season go longer. • Insulation Breakdown: lots of cause is for insulation breakdown. Humid conditions degrade the insulating properties of wires and cables, compromising electrical safety and performance. Automatic Dehumidifier & Temperature Controller are available to combat the negative effects of humidity on your electrical installations. Typical others like panel space heater, motor space heater, silica gel , canopy protection, sealing of switchgear rooms etc. are also available. • Material Compatibility and Degradation: availability of moisture in the air may like to cause problems for the efficient operation of electrical components because it prevents the materials from effectively connecting with one another. When moisture-sensitive adhesives or coatings are subjected to high levels of humidity.
Note: there is one scope i.e. earthing electrode where moisture content is helpful in decreasing specific gravity and finally reduce the earth resistance value.

Expandable barricade for electrical safety

Expandable barrier or barricade is used for temporary barricading. They are lightweight and easy to fold carry anywhere. It is frequently used by security department, police , Mall and many more. It is use for safety purpose in electrical construction or maintenance job. It is valuable in metal, plastic and fibre. Typical specification
1) Material: MS or Mild Steel 2) Side Structure of Pipe: Square 3) Wheels: to be provided 4) No of wheels : 4 nos. 5) Handle provided for lifting : to be provided 6) Reflective safety strip : Reflective Tape 7) Overall Height ( in cm) :85-100 8) Extendable Length ( in mtr ) :4.1 to 5 9) Collapsible Length ( in mtr ) :0.5 to 1 10) Thickness of Movable strip (in mm): 3 to 4 11) Coating: Synthetic Enamel Paint , more than 70 micron 12) Warranty : 12 months 13) Availability of Test Report from : not required 14) Test Report to be submitted to : not applicable 15) Colour : yellow and black 16) LOGO sticker : yes

Thursday, 4 July 2024

Cable, wire, machinery and relevant equipment

Cable , wire and Testing Equipment
 2. Annealer & Heat Treating plan 
 3. Braiding Machines 
4. Cables 
5. Capstans, Dancers, Accumulators, Preheaters 
6. Conductors & Wires 
7. Dies & Die Making Equipment 
8. Drives, Controls & Process Tools 
9. Extrusion Lines, Equipment & Tooling 
10. Fiber Optic Cable & Optical Fiber Manufacturing Equipment 
11. Fillers, Insulation, Jacketing / Sheathing Compounds & Colorants 
12. Guides, Pulleys, Sheaves, Rollers etc 
13. Marking and Printing Machines & Materials 
14. Optical Fibre Cables 
15. Payoffs and Takeups 
16. Plating, Galvanizing etc
 17. Reels, Spools, Baskets, Cores, Carriers & Packaging 
18. Respoolers
 19. Rolling Mills, Flattening & Shaping 
20. Rotating Machinery: Bunchers, Cablers, Stranders, Twinners etc 
21. Surface Treatment Systems: Cleaning, Pickling, Coating, Chalking, Descaling etc 
22. Tape Applicators, Binders, Armouring, Serving Heads 
23. Tapes, Yarns & Binders 
24. Tension Controls, Brakes, Clutches, Traverses 
25. Wire & Cable Handling Equipment 
26. Wire & Rod Drawing Machinery 
27. Wire Bending, Forming & Fabricating 
28. Wire Rod 
29. Wires & Conductors

Saturday, 10 February 2024

One Nation, One electrical License

Electrical contractors are facing license problem when they bid for another state. Generally they are entitled to do work in particular state from where they have got license. CEA advocated that there was the need of “One Nation, One Licence” for electrical contractors so that they can take up works in various states on the basis of a valid licence in any state or Union territory. This will avoid the long-drawn process of obtaining a separate licence in the respective state/UT, where the electrical contractor intends to work, the communication said. This proposal comes in the wake of a meeting with all state electrical inspectorates convened by Chief Engineer, CEA, on September 29, 2023. Most states welcomed the step of “One Nation, One Licence” for electrical contractors. It is interesting to note that supervisor licence holders and wireman licence holders of different states are allowed to work in other states through various arrangements like reciprocal MoUs, verification, endorsements, etc. However, no such procedure is allowed for electrical contractors, as yet. In light of this, CEA has advised that all state electrical inspectorates in which there is currently no such procedure of allowing electrical contractors of other states, to take up measures to facilitate inter-state validity of licences. This could be achieved by endorsement/verification of contractor licences issued by other states, by the state where the electrical contractor intends to work. CEA has also suggested that such endorsement should take no more than 15 days, subject to fulfilment of conditions precedent. CEA has also advised state electrical inspectorates against putting territorial restrictions while granting (new) licences to electrical contractors.

Pre activity before installation of new transformer in the place of old transformer

Installation of new transformer 2.5 MVA 6.6/0.433 KV in the palce of old transformer Some times it becmomes requirement to replace the ele...