## Perencanaan Listrik Pabrik Kelapa Sawit (Palm Oil Mill)

3.1       General Data

The electrical system in this circumstances are 220/380 volts, 3 phase, 4 wire, 50 Hz electrical supply for control circuit shall be 240 volts A.C All electrical of motor above 30 Hp shall fit with thermostat control to prevent over heating of windings.

Main cable for diesel genset and steam turbo alternator must be used 0,6/1kV NYY power cable. Sub Main Cable for incoming to MCC, Switch Board and LDB used 0,6/1 kV NYFGbY power cable. Cable connections are not permitted under the land. Cable that comes out above the surface of the security given pipe or flexible pipe. Supporting building and street lighting used underground cable.

All cable and wire inside buildings shall be of cooper conductor, PVC seated 600/1.000 volt grade insulation, having cross sectional area not less than 2.5 sq.mm and complying with Standard Industri Indonesia (SII).

3.2       Studi Kasus (MCC-03 Pressing Station)

Penghantar dari terminal generator ke proteksi pertama harus mempunyai kemampuan arus tidak kurang dari 115 % dari arus pengenal yang tertera pada pelat nama generator. (PUIL 5.6.1.3)

Perhitungan Cable dari Turbo Alternator ke Main Switchboard

Turbo Alternator data :

• Rated Power = 1200 kW
• Rated Current = 2279 A
• Cable sizing current = 2281.72 x 1.15 = 2621 A
• Estimated cable length = 25 m
 No. of cores 1 core Conductor cross-section area (mm2) 500 Rated current at 45oC (A) 990 Derating factor 0.75 Derated ampacity (A) 0.75 x 990 = 743 Quantity of cables per phase (round up) 2621 ÷ 743 = 3.5 ≈ 4 Total cable cross-sectional area (mm2) 14 x (1c x 500) mm2 Total number of cables installed 4 cable per phase Resistance at 90oC (Ω/km) (XLPE) 0.066 Reactance at 50 Hz (Ω/km) 0.099 Power factor, Cos φ 0.8 Sin φ 0.6 Percentage volt drop (%) 0.73 < 5 %

% VDrop = (√3 x 25 x 2279 x ((0.066 x 0.8) + (0.099 x 0.6)) x 100)/(380 x 4 x 1000)

=  0.73

Perhitungan Cable dari Main Switchboard ke MCC-04 Pressing Station

MCC data :

• Rated Power = 240.5 kW
• Rated Current = 456.75 A
• Cable sizing current = 456.75 x 1.25 =  571 A
• Estimated cable length = 47 m
 No. of cores 4 core Conductor cross-section area (mm2) 185 Rated current at 45oC (A) 355 Derating factor 0.9 Derated ampacity (A) 0.9 x 355 = 319.5 Quantity of cables per phase (round up) 571 ÷ 319.5 = 1.79 ≈ 2 Total cable cross-sectional area (mm2) 2 x (4c x 185) Total number of cables installed 2 cable per phase Resistance at 90oC (Ω/km) (XLPE) 0.137 Reactance at 50 Hz (Ω/km) 0.104 Power factor, Cos φ 0.8 Sin φ 0.6 Percentage volt drop (%) 0.84 < 5 %

% VDrop = (√3 x 47 x 456.75 x ((0.137 x 0.8) + (0.104 x 0.6)) x 100)/(380 x 2 x 1000)

=  0.84

Perhitungan Cable dari MSB ke Crane Grapple

Crane Grapple data :

• Rated Power = 50 kW
• Rated Current = 95 A
• Cable sizing current = 95 x 1.25 = 119 A
• Estimated cable length = 88 m
 No. of cores 4 core Conductor cross-section area (mm2) 35 Rated current at 45oC (A) 138 Derating factor 0.9 Derated ampacity (A) 0.9 x 138 = 124.2 Quantity of cables per phase (round up) 119 ÷ 124.2 = 0.95 ≈ 1 Total cable cross-sectional area (mm2) (4c x 35) Total number of cables installed 1 cable per phase Resistance at 90oC (Ω/km) (XLPE) 0.677 Reactance at 50 Hz (Ω/km) 0.117 Power factor, Cos φ 0.8 Sin φ 0.6 Percentage volt drop (%) 2.42 < 5 %

% VDrop = (√3 x 88 x 95 x ((0.677 x 0.8) + (0.117 x 0.6)) x 100)/(380 x 1 x 1000)

=  2.42

Perhitungan Cable dari MCC-04 Pressing Station ke Crude Oil Pump

Motor data :

• Rated Power = 7.5 kW
• Rated Current = 14 A
• Cable sizing current = 14 x 1.25 = 18 A
• Estimated cable length = 40 m
• Starter = Star Delta
 No. of cores 4 core Conductor cross-section area (mm2) 2.5 Rated current at 45oC (A) 25 Derating factor 0.9 Derated ampacity (A) 0.9 x 25 = 22.5 Quantity of cables per phase (round up) 18 ÷ 22.5 = 0.8 ≈ 1 Total cable cross-sectional area (mm2) 2 x (4c x 2.5) Total number of cables installed 1 cable per phase Resistance at 90oC (Ω/km) (XLPE) 9.6 Reactance at 50 Hz (Ω/km) 0.158 Power factor, Cos φ 0.8 Sin φ 0.6 Percentage volt drop (%) 2.02 < 5 %

% VDrop = (√3 x 40 x 14 x ((9.6 x 0.8) + (0.158 x 0.6)) x 100)/(380 x 1 x 1000)

=  2.02

Lampiran

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## Methodology Perhitungan Susut Tegangan dan Arus Ampere

2.1       Perhitungan Full Load Current (IFL)

2.1.1    Mengacu pada data vendor atau Handbook

2.1.2    Rumus :

• 3 phase circuit sistem AC :

I FL  =  (kW x 1000)/(√3 x V SYS x cos φ x E FF)

Dimana :

VSYS              System Voltage (V)

φ                Sudut pergeseran arus dan tegangan (degree)

Eff                    Power Efficiency

• Single phase circuit sistem AC :

I FL  =  ( kW x 1000)/(V SYS x cos φ x E FF)

• Sistem DC :

I FL  = (kW x 1000)/(V SYS)

2.2              Perhitungan Susut Tegangan

2.2.1    3 phase circuit sistem AC :

% VDROP =   (√3 x l x IFL x (R cos φ + X sin φ) x 100)/(VSYS x n x 1000)

Dimana :

VSYS                      System voltage (V)

% V DROP               volt drop (%)

l                             Length (m)

R                           Cable resistance (Ω/km)

X                           Cable reactance (Ω/km)

φ                            Sudut pergeseran fasa (degree)

n                            Number of cables in parallel per phase

2.2.2        Single phase circuit sistem AC :

% VDROP =  (2 x l x IFL x (R cos φ + X sin φ) x 100)/(VSYS x n x 1000)

2.2.3        sistem DC :

% VDROP =  (2 x l x IFL x R x 100)/(VSYS x n x 1000)

2.3              Resistance Konduktor

2.3.1    Resistance Formula

R = ρ x (l /A)

Dimana :

R   Resistance (Ω/phase)

ρ    Tahanan Jenis (Ω.mm2/m)

l     Panjang Konduktor (m)

A   Luas Konduktor (mm2)

2.3.2        Resistance Fungsi dari temperature

R = Ro [ l + α (t-20)]

Dimana :

Ro   Resistance at t = 20oC

t     Conductor temperature (oC)

α    0.00393 for Copper

2.4              Reactance

X = 2 x f x π x L x l

Dimana :

X   Reactance (Ω/phase)

f     Frequence (Hz)

L    Inductance (H/m)

l     Conductor length (m)ф