Shipboard Power Quality, Harmonic Load & Transformer Capacity Tool
Turn shipboard nonlinear loads into a transformer and distribution-bus
capacity screen. Model fundamental and harmonic RMS current, user-entered
transformer derating, neutral current from triplen harmonics, measured
voltage distortion, load losses, active-filter sizing and the point where
a power-quality problem becomes a capacity problem.
Currency selector changes display only. No exchange-rate conversion is performed.
Bus & Transformer
Use the transformer or distribution transformer actually carrying the
modeled load group.
V
kVA
%
Use an OEM, design-office or project derating factor. The tool does
not invent a transformer derating curve.
% usable capacity
A
Linear & Nonlinear Loads
kW
%
kW
%
% of I1
%
Used to estimate balanced 3-phase, 4-wire neutral current.
Measured Power Quality
%
%
%
%
%
User-entered project limit for screening. It is not a built-in
regulatory threshold.
Loss & Mitigation Economics
kW
hours/year
$
/kWh
A
%
$
$
$
Load Groups
Build the fundamental load from actual demand groups. Harmonic current is
entered separately in the spectrum table.
Use
Load Group
kW
PF
Demand %
Bus Harmonic Spectrum
Enter each harmonic current as a percentage of total bus fundamental
current I1. Triplen orders are automatically included in the
neutral-current screen.
Use
Harmonic Order
Current % of I1
Bus, Transformer & Measured Quality
V
kVA
%
%
A
%
%
%
%
%
Loss & Mitigation Economics
kW
hours/year
$
/kWh
A
%
$
$
$
Engineering note:
transformer harmonic capacity is not derived from THDi alone. This tool
keeps nameplate capacity, user-entered harmonic-service derating, RMS
current, harmonic spectrum and K-factor demand separate so a screening
result does not masquerade as an OEM thermal rating.
Enter bus, load, harmonic and transformer assumptions to build the
power-quality capacity screen.
Shipboard Electrical Capacity Decision
N/A
RMS Transformer LoadN/A
Total Current THDN/A
Neutral CurrentN/A
Filter PaybackN/A
Power Quality Cockpit
Each ring is normalized to your entered project limit or capacity
target, not a hidden standard
Electrical One-Line Load Path
Separates fundamental power from harmonic current before it reaches
the transformer and bus
Demand Load
N/A
›
Harmonic Current
N/A
›
Transformer
N/A
›
Distribution Bus
N/A
Transformer Capacity Lanes
Orange marker is the preferred maximum loading on usable
harmonic-service capacity
Harmonic Signature
Current distortion and triplen contribution
Neutral & Transformer Loss Exposure
Triplen harmonics can add in a 4-wire neutral while RMS current also
raises current-related transformer losses
Neutral Loading
Current-Related Loss Cost
N/A
Mitigation Decision Board
Compares the present condition, the entered active-filter scenario
and a transformer-capacity upgrade
Capacity & Filter Sizing Metrics
Useful design-office numbers for the next engineering conversation
Power Quality Issue Register
Flags only against the limits and ampacities entered in this tool
Advanced Load Group Detail
Demand-adjusted fundamental load and current contribution
Load Group
Demand kW
PF
kVAR
kVA
I1
Filter Sizing Sensitivity
Post-mitigation adjusted transformer loading versus filter rating and
harmonic reduction target
Reduction \ Filter
50% Rating
Base Rating
150% Rating
Model approach:
fundamental load is built from demand-adjusted kW and displacement power
factor. Total fundamental current comes from combined P and Q. Harmonic
RMS current is entered directly as THDi in Simple mode or derived from
the entered spectrum in Advanced mode. Transformer RMS current =
√(I1² + Ih²). Usable harmonic-service capacity is nameplate kVA × the
entered capacity factor. Advanced K-factor demand uses the entered
harmonic spectrum as Σ(h² × Ih²) / Irms² including the fundamental term.
Balanced triplen harmonics are assumed to add in the neutral. Transformer
load-loss cost uses the entered rated-current load loss scaled by squared
RMS current ratio. The active-filter case is limited by both filter
ampere rating and the entered target reduction.
Electrical engineering screening only.
Harmonic behavior depends on source impedance, transformer design, generator
characteristics, converter topology, load diversity, cable impedance,
resonance, capacitor banks, filter tuning, grounding, phase loading and
operating mode. K-factor demand is a spectrum indicator, not an automatic
transformer rating or derating instruction. Neutral-current modeling assumes
a balanced 3-phase, 4-wire system for triplen harmonics, and post-filter
neutral current assumes the entered harmonic reduction acts proportionally
on the triplen content. Current-related transformer loss is a simplified
I²-based estimate and does not separately model frequency-dependent eddy or
stray losses. Measured THDv and voltage-unbalance limits are user-entered
planning criteria. Validate equipment loading, protection, cable ampacity,
harmonic compliance and mitigation design using power-quality measurements,
short-circuit and harmonic studies, transformer OEM data and the vessel's
approved electrical design.
