c&i cables tests

© LANCO Group, All Rights Reserved © LANCO Group, All Rights Reserved

POWER EPC INFRASTRUCTURE SOLAR RESOURCES

Lanco Babandh Power Ltd

(C&I Cables Testing Methods)

PRATYUSHA KHANDELWAL

Source : Thermo Cables Limited, Hyderabad: 19.Nov.2012-23.Nov.2012

© LANCO Group, All Rights Reserved

Types of Cables:

• Power Cables/Control Cables

• Instrument/TC/Signal Cables

Note: Only Instrument cables have drain wires


Material used in Cables:

• TYPE: Y13 = Conductor Insulation(VDE 0207PT4)

• TYPE: A = Conductor Insulation

• XLPE = Conductor Insulation

• TYPE: YM1 = Inner Sheath (VDE 0207PT5)

• ST1 = Outer Sheath

• ST2 = Outer Sheath

*Note: Credentials validity must be up to 5 yrs approved by CPRI/NABL/NTH etc


Nomenclature:

Ex: 3C/P/T/Q 16 SQ MM 1100V FRLS TCL 2012 315M

Job ID: XXXXXX

Customer No. DVWS

Job No./ASC: 303468

Size: 8P x 0.5 sq.mm

DRM No. 1004883

QTY: 465 M *ASC= Armoured Screen Cable


Tests for Cables:

Type/Routine Tests: (100% of the given lot)

1) HV Test/High Pot. Test

2) Conductor Resistance Test

3) Drain Wire Resistance Test

4) Insulation Resistance Test


Tests for Cables:

Acceptance Tests: (10% of offered lot of each cable size as applicable)

1) Construction detail verification(Conductor/Insulation system/ Pairing/ Laying/Pair/Overall Shielding/Inner sheathing /Armoring/Outer sheathing)

2) Conductor Resistance Test

3) Capacitance, Inductance & L/R Ratio Test

4) Tensile strength and elongation at break for insulation and sheath before and after ageing

5) Thermal Stability Test

6) Cross Talk/Attenuation Test

7) Insulation Resistance measurement

8) Insulation thickness measurement

9) Color identification of cores

10) Annealing Test

11) Volume Resistivity Test

12) Hot Deformation Test


Acceptance Tests:

FRLS & ART:

1) Oxygen Index Test.

2) Temperature Index Test.

3) Smoke Density Test.

4) Flammability.

5) Swedish chimney/Flame Retardant Test.

6) Acid gas generation test.

7) Anti rodent test.


HV Test:

IS : 10810 Part 45

• HV Tester

• For Control Cables: 3kV ACrms for 5 minutes(C-C)

3kV ACrms for 5 minutes(C-Armour)

• For TC/Instrument Cables: 1kV ACrms for 1 minutes(C-C)

1kV ACrms for 1 minutes(C-Screen)

*Note: Drain wires are only present in Instrument cables


Conductor Resistance & Drain Wire Resistance Test:

• BS: 5308 Part-2

• IS: 10810 Part-5

• Digital Ohm Meter

• Probe Calibration Test- 0.0 at NTP

• At 20°C, R= [Rx.k.1000/L]; Ω/km [max. 36.6]

where, k= 250/(230+T)

*Drain wire: 30 Ω,max /Conductor Wire: 36.6 Ω,max


Insulation Resistance Test:

• IS: 10810 Part-43

• Insulation Tester

• IRconstant = LxR/[1000Log10(D/d)]; MΩ-km

• Min. 100MΩ/km • C-C

• C-Shield

• Insulation

• L/R


Capacitance, Inductance & L/R Ratio Test:

• BS: 5308 – I & II

• Digital LCR Q Meter

• Frequency is set at 1kHz

• OC & SC test is done

• Capacitance b/w cores= Cc x 1000/L in nf/km [max. 250]

• Capacitance b/w core to shield + armor = Cs x 1000/L in nf/km [max. 400]

• Inductance = L x 1000 x 1000/L in mH/km [max. 1]

• L/R = obs. Inductance/loop resistance; µH/Ω [max. 25]


continued…

PARAMETER PVC INSULATION XLPE/LDPE INSULATION

Capacitance b/w cores Max. 250 nf/km Max. 100 nf/km

Capacitance b/w core-shield Max. 400 nf/km Max. 400 nf/km

Inductance for signal cables Max.1mH/km Max.1mH/km

Inductance for TC cables Max. 4mH/km Max. 4mH/km

L/R ratio up to 1 mm² Max. 25µH/Ω Max. 25µH/Ω

L/R ratio 1- 1.5 mm² Max. 40µH/Ω Max. 40µH/Ω

L/R ratio 2.5 mm² Max. 50µH/Ω Max. 50µH/Ω


Ageing Test:

• IS: 10810 Part-11

• Tensile strength and elongation at break for insulation and sheath before and after ageing is done.

• 7 Days test at specific temp. of 80°C, 100°C etc

• Sheath-dumb-bell shape & Insulation-tubular shape; each sample of ≥ 100mm is taken.

• 20 mm marking is done on each test sample and tested at 50kg wt. tensile & elongation tester.

• Tubular Cross sectional Area, A = ∏/4[ D² – d²]; mm²

• Dumb-bell Cross sectional Area, A = width x thickness; mm²

• T.S. = BL x 9.8/ A; N/mm²

• % Elongation = [L-L0]/L0 x 100 in %

• Variation in T.S. = [TS0 – TSx]/TS0 x 100 in %

• Variation in Elongation = [EL0- ELx]/EL0 x 100 in %

Note: BL at fractured point shall not be greater than 250 mm/min.

Material T.S. % Elongation

PVC 12.5 N/mm² min. Min. 150 %

LDPE 10 N/mm² min. Min. 300%

XLPE 12.5N/mm² min. Min. 200%


Ageing Test: continued…

Material Variation in T.S. Variation In Elongation

TYPE A Max. ± 20% Max. ± 20%

TYPE C Max. ± 25% Max. ± 35%

TYPE ST1 Max. ± 20% Max. ± 20%

TYPE ST2 Max. ± 25% Max. ± 25%

TYPE ST2 with FR/FRLS Max. ± 25% Max. ± 25%

XLPE Max. ± 25% Max. ± 25%

Material Set Temperature Duration of Test

TYPE A 80±2 °C 7 Days

TYPE C 135±2 °C 7 Days

TYPE ST1 80±2 °C 7 Days

TYPE ST2 100±2 °C 7 Days

TYPE ST2 with FR/FRLS 100±2 °C 7 Days

XLPE 135±2 °C 7 Days


Thermal Stability Test:

• IS : 5831-1984

• Digital Temperature Controller

• Temp.: 200°C

• Time: 40 Minutes

• PH paper color changes

Type of Material Test Duration

TYPE A, FRLS, PVC 80 minutes( min.)

TYPE C 100 minutes( min.)

TYPE ST1, FRLS 40 minutes( min.)

TYPE ST2, FRLS 80 minutes( min.)


Cross Talk/Attenuation Test:

• LF Source & Selective Level Meter

• Frequency is set at 800Hz, Voltage = 10mV

• Attenuation = 20 log10[Vmax/Vmin]; dB

• It should be ≤ 1.2 dB(max.)

• Cross Talk ≥ 60 dB(min.)


Annealing Test:

• Test Sample: L1 = 250 mm marked

• %age = [(L2 – L1)/ L1] x 100

• Annealing Test for conductor must be min. 18%

• Ex: L1 : 250, L2 : 310 24%


Volume Resistivity Test/Water Immersion Test:

• IS: 10810 Part-45

• VR is tested at ambient temp. and at rated temp. of 70°C

• Voltage = 500V

• Test Sample, L = 3.5 mtrs

• VR = [observed resistivity x 2∏ x L x e⁸]/ log(core dia./conductor dia.); MΩ-cm

Material At ambient temp.(27°C) At rated temp.(70°C)

PVC Type A Min. 1 x 10^13 Ω-cm Min. 1 x 10^10 Ω-cm at 70°C

PVC Type A, FRLS Min. 1 x 10^13 Ω-cm Min. 1 x 10^10 Ω-cm at 70°C

PVC Type C Min. 1 x 10^13 Ω-cm Min. 1 x 10^10 Ω-cm at 85°C

XLPE Min. 1 x 10^14 Ω-cm Min. 1 x 10^12 Ω-cm at 90°C

LDPE Min. 1 x 10^15 Ω-cm Min. 1 x 10^12 Ω-cm at 70°C


Smoke Density Test:

• ASTM D 2843

• Smoke Density test apparatus

• Pressure gauge pointer

• Gas flow at 40 psi or 2.8 kg/cm²

• % of light absorbed at 15 sec interval for 4 minutes ie 16 values.

• Rating = [ (Sum of 1 to 15 values) x 2 + 16th value] / 32 in %

• 60% for FRLS PVC (max.)

• 20% for ZHFR (max.)

• Vdc = 5.8V

• Ex: For a sample, the absorption % is as follows:

1 min : 14%

2 min : 28%

3 min : 31%

4 min : 29%


Swedish chimney/Flame Retardant Test:

• IS: 10810 Part-61 & SS 424-1475 F3

• Specimen Length: 850 mm and ext. dia. should not exceed 35 mm

• Stop watch

• Unaffected portion from top shall be min. 300mm

• Ex: Test Sample Dia, D =20 mm

Ethanol Qty(ml) = Time(min) x 20 = [1+D/5] x 20

= 100 ml

Total Length = 850 mm; Undamaged sample after test= 610 mm


Oxygen Index Test/ Temperature Index Test:

• ASTM D 2863

• Oxygen is 100% and N2 is 0%

• Flame is inserted

• OI = 29%(min.) and Temp. : 30°C;

• At 32, 32.5, +0.5°C likewise increases it.

• TI, at 50°C, 80°C

• TI = 250°C(min.)


Flammability:

• IEC: 332 Part-3

• Ladder length : 4 meters

• Cable length : 2.5 meters

• Time : 20 minutes

• LPG flow: 0.25 kg/cm²

• Air flow: 2.4 kg/cm²

• Sample Result: 1.35 mtrs burned


Acid gas generation test:

• IEC: 60754-Part I

• Test Sample: 1 gms

• Electronic Balance

• Digital Temp. Controller

• Pressure air flow meter

Procedure:

• 4 gm NaOH+ 1 ltrs distill water is made

• 440ml soln of NaOH is made.

• 200ml soln is taken out seperately.(Original Sample)

• One sample is put at 800°C for 40 minutes (Test Sample)


Acid gas generation test: continued

Titration: • 200ml soln. of each is taken out from 440ml NaOH+ 1000ml distill water

• 4ml Nitric Acid is added in both samples

• 3ml Nitro Benzene(C6H5NO2) is added in both samples

• 20ml AgNO3 is added in both samples

• 1ml (40% ferric ammonium) is added in both samples

• 0.1 M Ammonium Tryo Cyanate, NH4CNS (50ml) filled in burate

• Now, original sample is stirred, and burate valve is opened.

• Original Soln. color changes at X ml and Test soln. color changes at X+Y ml

• % of HCL can be max. 20 in mg/g


Acid gas generation test: continued

• Ex: Cable: 3C x 16 sq.mm

• Test Sample: 1.0071 gms

• Original Soln.: 23ml & Test Soln.: 37ml

• HCL % = 3.65 x 0.1 x (B-T) x (1000/200)/Weight of test sample

= 3.65 x 0.1 x (23-14) x (1000/200)/ 1.0071

= 16.30 %


ART: Anti rodent & termite repulsion test:

• IS : 5831-1984

• Ash of cable is taken.

• Sodium Sulphide flakes(fused), Na2S.xH2O are mixed with distill water in other bowl.

• Ammonium Acetate soln. + Distill water + Ash all the three are put in oven for 10 minutes at 80 °C

• After 10 minutes, sample is filtered and mixed with H2SO4.

• We get brown spots, it means Lead is present in the given sample.


Important Cable Testing Standards:

• IS 5831: PVC Compound

• BS 7655: ZHFR

• IS 8784, IEC 60584-1&3, ANSI MC 96.1: TC Cables

• IS 10810: Methods of tests for cables

• BS 5308-I&II : L/R Ratio

• BS 5308P2, IS 10810P5: Drain wire test

• IS 5831, IS 10810P60: Thermal Stability

• ASTM D 2863: Oxygen Index & Temp. Index Test

• ASTM D 2843: Smoke Density Test

• IEC-60754P1: HCL gas test

• IS 10810P62, IEC 332P3: Flame Retardance Test for bunch of cables

• IS 10810P61 & SS 424-1475: Swedish Chimney Test

• IEC 332P1: Flammability Test

• IEC 60331: Fire Survival Test

• IS 10810P12: Shrinkage Test

• IS 10810P10: Loss of mass

• IS 10810P14: Hot shock Test

Data Sheets

Test Certificates


PK [email protected]

9/14/2015 12:12 AM

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