Rıhtım vinçleri, liman ekipmanları ve ark ocakları için beslemeyi tasarlayın — darbe yükü reaktif kompanzasyonu (SVC/SVG), harmonik filtreleme ve motor yol verme gerilim düşümü kontrolü, malzeme listesi ve tek hat şeması ile birlikte.
Vinçler ve ark ocakları aşırı darbe yükleridir: hızlı salınımlar gerilim titremesine neden olur ve VFD/doğrultucu sürücüler yoğun harmonik enjekte eder. Bu hesaplayıcı, transformatörü ortalama talep için boyutlandırır, en büyük sürücü yol verme düşümünü kontrol eder ve dinamik reaktif kompanzasyon ile detuned harmonik filtrelemeyi boyutlandırır.
regenerative VFD (energy feedback on lowering) · per crane
4
Shore power supply (岸电)
300 kVA
50/60 Hz frequency converter + shore connection panel · IEC/ISO 80005-1 · quoted per project
1
📐 Single-line diagram
⚙️ Electrical schematic (protection & metering)
⛳ Grounding grid layout
🔌 Cable schedule & routing
🗄 Switchgear arrangement
🛡 Protection configuration
📋 Protection settings
Circuit
Protection
Setting
Time
Standard
HV incoming 35 kV
50 instantaneous
211 A
inst
IEC 60255-151 / IEEE 242
HV incoming 35 kV
51 overcurrent
32 A
0.5 s
IEC 60255-151 / IEEE 242
HV incoming 35 kV
51N earth-fault
5 A
0.5 s
IEC 60364-4-41
Transformer 1600 kVA
49 thermal overload
79% of rated
alarm 90%
IEC 60076-7 / IEEE C57.91
LV incoming 0.4 kV
50 instantaneous
18475 A
inst
IEC 60947-2
LV incoming 0.4 kV
51 overcurrent
2771 A
0.3 s
IEC 60947-2 / IEC 60255
LV incoming 0.4 kV
51N earth-fault
462 A
0.3 s
IEC 60364-4-41
Quay crane 1
50/51/51N (MCCB)
Ir 1134 A - Im 8248 A - Ig 206 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
Quay crane 2
50/51/51N (MCCB)
Ir 1134 A - Im 8248 A - Ig 206 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
Quay crane 3
50/51/51N (MCCB)
Ir 1134 A - Im 8248 A - Ig 206 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
Quay crane 4
50/51/51N (MCCB)
Ir 1134 A - Im 8248 A - Ig 206 A
0.1 s (grading)
IEC 60947-2 / IEC 60255
Settings are illustrative starting points — confirm with a protection coordination study per IEC 60255 / IEEE 242.
📚 Calculation book
CALCULATION BOOK
1600 kVA - 35kV/0.4kV - single - illustrative
1. Load calculation
Standard: IEC 60076 - IEC 60364-5-52
Parameter
Formula
Value
Connected load
P = sum(kW)
2,000 kW
Demand factor
Kd
0.6
Demand power
Pd = P x Kd
1,200 kW
Power factor
cos(phi) before -> after
0.70 -> 0.95
Design apparent power
Sd = Pd / cos(phi)
1,263 kVA
Transformer loading
Sd / Srated
79%
2. Short-circuit calculation
Standard: IEC 60909
Parameter
Formula
Value
System impedance (pu)
Zs = S / Ssc
0.32% (on 1600 kVA base)
Transformer impedance
Zt = Z%
4%
Total impedance
Z = Zt + Zs
4.32%
LV prospective Isc
Isc = In / Z
53.5 kA
HV prospective Isc
Isc = Ssc / (sqrt(3) x V)
8.2 kA
Breaking check
Icu >= Isc
LV 65 kA (1.2x margin) PASS
3. Voltage drop
Standard: IEC 60364-5-52 Annex G
Parameter
Formula
Value
Main feeder
dU = sqrt(3) x I x L x R / V
300 mm2 - dU 1.50% @ 100 m
Limit
max 3%
within limit
Transformer volt. reg.
dU ~ loading x Z% x sin(phi)
1.0% at full load
4. Reactive power / harmonics
Standard: IEC 61921 (PFC) - IEEE 519 (harmonics)
Parameter
Formula
Value
Required compensation
Qc = Pd x (tan1 - tan2)
0 kvar
PFC bank
standard step
0 kvar
Detuned reactor
p = 6%
n/a
5. Grounding
Standard: IEC 60364-5-54 earthing arrangements and protective conductors LV earthing target 10 ohm (TN systems); 4 ohm used as a conservative design target - target 4 ohm
Parameter
Formula
Value
Single rod resistance
R1 = rho/(2 x pi x L) x ln(4L/d)
39.6 ohm
Rods required
n = R1 / (target x 0.8)
13 rod(s) <= 4 ohm
Rod spec
dia x length
20 mm x 2.5 m
This calculation book is illustrative it consolidates the computed values with the referenced standards. A licensed engineer must verify and seal final design documents for construction.
Cable & grounding pricing:Cable conductors and grounding are priced from the confirmed cables-trays-grounding price reference (per-metre copper YJV; aluminium remains POA). The main copper busbar is POA — its length is project-specific.
Busway (high-current feeders):For LV feeders above ~2500 A, a busway (母线槽) trunking system is recommended instead of parallel cables.
Impact load:Impact factor 1.3× — rapid load swings from cranes/arc furnaces cause voltage flicker; dynamic SVC/SVG compensation is required.
Starting:Largest 500 kW drive started via VFD draws a 2.2% bus dip (within the 10% limit).
Harmonics:30% THDi from VFD/rectifier loads — a 7% detuned filter keeps the branch inductive below the 5th harmonic.
SVC/SVG pricing:Dynamic reactive compensation is priced at $183,000/unit (±5 Mvar, FOB reference).
Crane regenerative drive:Quay cranes use four-quadrant (regenerative) VFDs that feed lowering energy back to the bus — this reduces energy consumption and DC-bus overvoltage, quoted per project.
Shore power (岸电):A shore power supply converts the port grid to the vessel’s voltage/frequency (IEC/ISO 80005-1) so berthed ships shut down their auxiliary engines — quoted per project.
Nasıl hesaplandı
Boyutlandırma nasıl çalışır
Darbe tepe değeri = bağlı yük × darbe faktörü. Reaktif kompanzasyon Qc = P × (tanφ₁ − tanφ₂) düşük doğal güç faktörünü düzeltir; titreme için hızlı bir SVC/SVG ve harmonikler için detuned bir bank kullanılır. En büyük sürücü yol verme kVA değeri, bir gerilim düşümü limitine (titreme hassasiyetli baralar için tipik olarak %10) karşı kontrol edilir.
Geçerli standartlar
Boyutlandırma, GB/T 12326 (gerilim dalgalanması ve titreme), GB/T 14549 ve IEC 61000-3-2 (harmonikler), IEC 61642 (detuned filtreler), IEC 60034 (dönen makineler) ve GB 50052 (güç besleme tasarımı) standartlarına dayanır.
Sıkça sorulan sorular
How do impact loads affect power quality at a port?
Quay cranes and winches impose rapid, large load swings (impact loads) that cause voltage flicker. The impact factor is the ratio of peak to average load, often 1.3-1.5. When flicker violates GB/T 12326 limits, a dynamic reactive compensator (SVC or SVG) with 5-20 ms response is added. The calculator sizes compensation from the impact factor.
Why do arc furnaces need SVC or SVG compensation?
Electric arc furnaces draw erratic current with severe flicker and Harmonics, pulling Power Factor down to 0.6-0.7 during meltdown. An SVC or SVG rated 30-50% of furnace capacity restores power factor and damps flicker to meet GB/T 12326 and IEEE 519. A 50 MW furnace typically needs 15-25 Mvar of dynamic compensation.
What voltage level feeds a port crane system?
Large quay cranes (500 kW-1.5 MW per crane) are fed at 10 kV or 35 kV, stepped down near the berth to 0.4/0.69 kV for drives. A 10 kV ring feed with RMU or Switchgear along the quay is standard. The calculator's 35 kV default models a multi-berth crane cluster; smaller ports use 10 kV.
How are crane harmonics controlled?
Crane drives are VFD-based, injecting 5th, 7th, 11th harmonics; THDi commonly reaches 30% without treatment. Active front-end (AFE) drives or a passive detuned filter plus an APF keep THD under the IEEE 519 limit of 5-8% at the point of common coupling. The calculator sizes harmonic filtering when THDi exceeds the threshold.
What is the typical crane duty cycle for sizing supply?
Quay cranes run intermittent duty (hoist/lower/travel), so average demand is 40-60% of installed power even during busy periods. Supply transformers are sized to the peak simultaneous demand plus starting inrush of the largest hoist, not the sum of nameplates. The calculator applies an impact factor and diversity to avoid oversizing.
What short-circuit duty must port switchgear withstand?
Port 35 kV switchgear is usually rated 25-31.5 kA; 10 kV panels 25-31.5 kA; LV boards 50-65 kA. The rating must exceed the computed Fault Current at each busbar (IEC 60909). Crane drives contribute fault current, so a 35 kV bus fed by a 50 MVA source needs at least 25 kA. The calculator checks panel ratings against the fault level.
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Sonuçlar referans amaçlı mühendislik tahminleridir. Nihai tasarım, saha koşullarına ve geçerli yönetmeliklere göre yetkili bir yerel mühendis tarafından onaylanmalıdır. Fiyatlar FOB Qingdao (EXW) olup nakliye, gümrük vergisi veya montaj dahil değildir.
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