Calculadora de Sistema Elétrico para Parque Industrial
Dimensionamento da distribuição elétrica para uma fábrica ou parque industrial — carga total de equipamentos, fator de demanda, participação de motores e participação de fontes harmônicas, com seleção de transformadores e quadros de distribuição, compensação reativa e BOM.
Plantas industriais combinam cargas de motores, aquecimento e eletrônicas com fator de potência natural abaixo de 0,9 e harmônicos significativos. Esta calculadora converte a carga de equipamentos conectados em um pacote dimensionado de transformadores e quadros de distribuição, com compensação reativa e filtragem de harmônicos conforme GB 50052 e GB 50055.
Worked Examples
Example 1 — 2 MW Factory Load (Demand Factor, Motor & Harmonic Share) · FOB $257,923
Settings are illustrative starting points — confirm with a protection coordination study per IEC 60255 / IEEE 242.
📚 Calculation book
CALCULATION BOOK
1600 kVA - 10kV/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
0.82 -> 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)
28.9 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 1.20% @ 80 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.
Demand factor:0.6 demand factor avoids oversizing — not all plant equipment runs simultaneously at full load.
Motor & harmonic load:60% motor load (natural PF 0.82); 25% harmonic-source load (detuned PFC is sufficient.)
Zone / plant metering:For multi-tenant parks, per-zone / per-plant revenue-grade metering (分区分厂计量) at the LV feeder enables sub-billing and energy accountability — quoted per project.
Harmonic sources:Typical harmonic sources: VFD drives (THDi ~30%), rectifiers / electroplating (~25–35%), UPS (~10–20%), welding machines and LED lighting. The 25% share is applied as an aggregate — a detailed equipment list refines APF sizing.
Transformer loading:Transformer sized at the target PF 0.95; final capacity must be confirmed against the actual equipment schedule.
Como foi calculado
Como funciona o dimensionamento
Demanda P = carga conectada × fator de demanda Kd (nem todos os equipamentos operam simultaneamente). A participação de motores determina o fator de potência natural; a compensação reativa Qc = P × (tanφ₁ − tanφ₂) corrige-o para o FP alvo. A participação de fontes harmônicas fornece a corrente harmônica Ih = I₁ × THDi, filtrada por um banco de capacitores dessintonizado.
Normas aplicáveis
O dimensionamento segue GB 50052 (projeto de fonte de alimentação), GB 50055 (projeto de distribuição industrial de baixa tensão), GB/T 14549 (harmônicos) e IEC 60076 (transformadores).
Perguntas frequentes
What demand factor applies to an industrial park?
An industrial park with many factories never runs every machine simultaneously; a demand factor of 0.55-0.7 is typical. A 2000 kW connected load at 0.6 kd and 0.9 pf gives ~1330 kVA demand, so a 1600 kVA Transformer or two 800 kVA units suit. The calculator uses demand factor and motor share to size the MV/LV plant.
How much harmonic filtering does a factory-heavy park need?
When 60% of load is motors on VFDs and 25% is non-linear (rectifiers, UPS), THDi can reach 15-25%. IEEE 519 limits THD to 5-8% at the point of common coupling, so a detuned capacitor bank (7% Reactor) or APF is required. The calculator sizes compensation and detuning from the harmonic share.
What is the standard MV/LV architecture for an industrial park?
Typical architecture: 10 kV (or 35 kV) utility feed -> ring or radial MV Switchgear -> one transformer per factory or block -> 0.4 kV switchboards -> motor control centers. A 10 kV ring with RMUs along the ring offers N-1 supply. The calculator sizes the transformers, switchgear and compensation for the aggregated park load.
How do I allocate transformer capacity per factory?
Give each factory its own transformer sized to its demand plus 20-25% headroom, or share one large transformer for small tenants. Separate transformers isolate faults and simplify metering, but shared units cost less. The calculator aggregates the park demand and shows the single-transformer and split-transformer options.
What power factor should an industrial park maintain?
Utilities usually require 0.9-0.95 Power Factor and levy penalties below ~0.9. Industrial parks with motor-heavy load typically start at 0.75-0.85 and add capacitor banks to reach 0.95. The calculator computes the required kvar compensation to correct from measured pf to target and sizes the LV capacitor bank.
What redundancy does a park MV network usually provide?
A ring-main MV network with normally-open tie provides N-1 redundancy: any cable or RMU fault is isolated and load restored from the other direction. Radial feeders are cheaper but lose supply on a fault. The calculator's architecture notes cover ring vs radial options and their reliability trade-off.
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Os resultados são estimativas de engenharia para referência. O dimensionamento final deve ser confirmado por um engenheiro local licenciado, de acordo com as condições do local e os códigos aplicáveis. Os preços são FOB Qingdao (EXW) e não incluem frete, direitos aduaneiros ou instalação.
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