QDTB® TransformerQuality & Dependability, Trust Builder

All figures are configurator-generated feasibility-level estimates; drawings are schematic deliverables pending refinement by a licensed design institute, not construction documents.

600 kW / 630 kVA Port Terminal Power: 160 kW Quay Crane + SVG Dynamic Compensation Deep-Read

Q: What transformer for a 600 kW terminal?

480 kW ≈ 505 kVA → 630 kVA tier; N+1 uses 2×S13-M-630/10, 80% loading after one-unit loss.

Q: SVG vs plain capacitor compensation?

Capacitors only correct steady-state reactive; SVG responds <10 ms and handles both crane-surge flicker and 42% harmonics — SVG is mandatory here.

Q: Does the crane need a VFD?

Yes — 160 kW on VFD gives 1.7% dip (vs 8.2% DOL), plus smooth start/stop and regenerative braking.

Q: How is 42% THDi handled?

Stacked crane/RTG VFDs push THDi to 42%; use SVG active filtering + detuned reactor, target ≤8%.

Q: What does voltage flicker do?

300 kW crane surge causes bus flicker that can mis-trip adjacent feeders; SVG fast compensation holds the voltage.

Q: Where does crane-lowering regenerative energy go?

A regenerative drive returns braking energy to the DC bus, with a braking resistor to dissipate the excess.

Q: Is a backup source needed?

The grid-tied scheme has no diesel/UPS; N+1 dual transformers give transformer-level redundancy — add backup only for critical continuous duty.

Q: What's the payback on a better transformer?

SH15 amorphous vs S13 saves ≈2,803 kWh/yr ($337/yr), ~3 yr payback.

Q: Is the price final?

No — $156,706 is a feasibility-level estimate; crane regenerative drive and shore power are POA, and grid Ssc must be confirmed.

2×S13-M-630/10 N+1 · 160 kW crane VFD · SVG dynamic compensation

1 · TL;DR Conclusion

Conclusion: this 600 kW port terminal uses 2×S13-M-630/10 oil transformers (N+1) + a 160 kW quay-crane VFD + SVG dynamic reactive compensation — configurator total ≈ $156,706, 80% N-1 loading, THDi 42% mitigated by SVG, 160 kW crane dip 1.7% vs 8.2% DOL (feasibility-level).

•2×630 kVA S13-M-630/10 oil transformers (N+1), 80% loading after one-unit loss, 480 kW demand
•160 kW quay crane on VFD — 1.7% start dip vs 8.2% DOL; 300 kW impact load
•SVG dynamic compensation ($32,200) for the crane's regenerating/impact load and 42% THDi
•No backup source — grid-tied only; N-1 transformer covers crane + shore power
•Economics: $156,706 total; SH15 upgrade saves $337/yr, ~3 yr payback; losses 161,197 kWh/yr ≈ $19,344

2 · Solution Overview

A container terminal is a VFD-dense, impact-heavy load: quay cranes and RTGs surge on pickup and regenerate on lowering, causing voltage flicker that can trip neighboring feeders. This scheme uses N+1 oil transformers plus a 160 kW crane VFD and SVG dynamic compensation to hold voltage steady and clean the bus.

2×630 kVA (S13-M, N+1)

Transformer

10 kV (dual N+1)

Feed

480 kW (600 kW installed)

Demand

160 kW (VFD)

Crane VFD

300 kW

Impact load

$32,200

SVG dynamic compensation

42%

THDi

80%

N-1 loading

Source	Role	Share kW	Share
Grid 10 kV	base	480 kW	100%

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3 · Design Process & Rationale

1. Requirement identification

600 kW terminal: 450 kW power, 300 kW impact (crane), 250 kW nonlinear, 160 kW largest motor on VFD.

2. Load character

Crane impact 300 + nonlinear 250; demand 480 kW (Kd 0.8); cyclic starts, no long-term critical standby load.

3. Source

10 kV grid only (grid-tied); cranes cycle, no grade-1 standby load, so no diesel/UPS.

4. Transformer sizing

480 kW ≈ 505 kVA → 630 kVA tier; N+1 → 2×S13-M-630/10, 80% loading after one-unit loss.

5. SVG & harmonics

42% THDi + 300 kW impact → SVG dynamic compensation ($32,200) for flicker + reactive + harmonic.

6. Crane drive

160 kW VFD (1.7% dip); regenerative drive returns braking energy to the DC bus (quay crane regenerative drive item).

7. Protection

MV 31.5 / LV 36 kA breaking; selectivity 10.71×; modbus SCADA.

Pain Points → Solution → Evidence

Pain

Crane starts cause voltage flicker that dims other feeders

Solution

SVG dynamic compensation responds in <10 ms to hold the bus

Evidence

300 kW impact; SVG $32,200 auto-selected

Pain

VFD harmonics overheat the transformer

Solution

Detuned reactor + SVG active filtering

Evidence

THDi 42% (V6 warn)

Pain

Regenerative crane braking backfeeds the DC bus

Solution

Regenerative drive + braking resistor

Evidence

quay crane regenerative drive item (POA)

4 · Key Parameter Deep-Read

Parameter	Value	Basis	Impact & Boundary
Transformer capacity	630 kVA ×2 (S13-M)	505 kVA → 630 tier; N+1 → 2 units	80% loading, economical band 60–85% above ~540 kVA demand, step to 800
SVG dynamic compensation	$32,200	300 kW impact + 42% THDi auto-selects SVG	<10 ms response; flicker + reactive + harmonic PFC capacitors can't handle flicker; only SVG can
Crane motor	160 kW VFD, 1.7% dip	VFD kst 1.3 vs DOL 6.5	no sag; DOL would be 8.2% confirm regenerative drive & braking resistor
Impact load	300 kW	crane pickup/hoist instantaneous surge	sets SVG size & flicker suppression multi-crane coincidence factor to verify
Harmonics	THDi 42%	nonlinear 250 kW / 600 kW	needs SVG active filtering target THDi ≤8%
Demand factor	0.8 → 480 kW	installed 600 kW × Kd 0.8	sizes transformer at real demand verify against crane duty cycle

5 · Drawing Deep-Read

Dwg 3/23Single-line diagram — 10 kV → 2×S13-M-630/10 → MNS LV bus → crane feeders + SVG + shore power

Single-line diagram · QDTB Transformer · QDTB-DL1-E-03 · Dwg 3 / 23Rev. A · Not to scale · 2026-10-01 · Designed ______ · Checked ______ · Approved ______

Why: The SLD gives the structural skeleton: N+1 dual transformers + crane feeders + SVG branch + shore power — the source of 'crane surge doesn't take down the whole terminal'.

Dwg 19/23Reactive & harmonic compensation — THDi 42% · SVG dynamic compensation $32,200

Reactive & harmonic compensation · QDTB Transformer · QDTB-DL1-E-19 · Dwg 19 / 23Rev. A · Not to scale · 2026-10-01 · Designed ______ · Checked ______ · Approved ______

Why: 42% THDi + 300 kW impact exceed normal PFC capability; the PFC/SVG drawing specifies dynamic compensation — the core of flicker and harmonic mitigation.

Dwg 12/23Power quality assessment — Voltage flicker · THDi 42% · reactive

Power quality assessment · QDTB Transformer · QDTB-DL1-E-12 · Dwg 12 / 23Rev. A · Not to scale · 2026-10-01 · Designed ______ · Checked ______ · Approved ______

Why: The power-quality drawing quantifies crane-surge flicker and 42% harmonics, directly justifying the SVG selection.

Dwg 8/23Short-circuit calculation — LV 22 kA · breaking LV 36 kA (1.3× margin)

Short-circuit calculation · QDTB Transformer · QDTB-DL1-E-08 · Dwg 8 / 23Rev. A · Not to scale · 2026-10-01 · Designed ______ · Checked ______ · Approved ______

Why: The LV fault level of 22 kA forces 36 kA breaking on the LV switchgear — the equipment safety red line.

Dwg 15/23TCC protection coordination curve — Incomer → transformer → LV incomer → feeder, selectivity 10.71×

TCC protection coordination curve · QDTB Transformer · QDTB-DL1-E-15 · Dwg 15 / 23Rev. A · Not to scale · 2026-10-01 · Designed ______ · Checked ______ · Approved ______

Why: A terminal fears one fault stopping the whole berth; TCC verifies selectivity so a downstream fault trips only its feeder.

The following drawings are shown for reference (full set in the configurator “View design document”):

Dwg 4 · System topologyDwg 5 · Distribution systemDwg 6 · MV distribution systemDwg 7 · LV distribution systemDwg 9 · Applicable codes & standardsDwg 10 · Main equipment technical dataDwg 11 · Construction & testingDwg 13 · SCADA architectureDwg 14 · Protection configurationDwg 16 · Grounding systemDwg 17 · Lightning & surge protectionDwg 18 · Equipment layoutDwg 20 · Secondary control & signalDwg 21 · Terminal stripDwg 22 · Panel layoutDwg 23 · DC auxiliary power

6 · Operation Demo (Deep-Read)

Reliability

N+1 80% after one-unit loss; grid-tied with no backup — crane + shore power covered by dual-transformer redundancy.

Fault & protection

LV 22 kA / MV 28.9 kA, breaking LV 36 kA / MV 31.5 kA (1.3×); selectivity 10.71×.

Power quality

THDi 42% mitigated by SVG; crane VFD dip 1.7% (DOL 8.2%), bus 0.983 pu.

Economics

$156,706 total; SH15 upgrade ~3 yr payback ($337/yr); losses 161,197 kWh/yr ≈ $19,344.

Other views (shown): LCC (life-cycle cost) · Power quality & harmonics · Voltage profile · Scheme features · Arc flash

7 · Economics & Payback

Equipment total ≈ $156,706 (2×S13-M-630/10 + crane feeders + SVG dynamic compensation + modbus SCADA). No PV/BESS, so economics = capex + losses + transformer TCO: S13→SH15 amorphous upgrade saves ≈2,803 kWh/yr (≈$337/yr), ~3 yr payback; annual transformer+line losses ≈161,197 kWh (≈$19,344/yr). Crane regenerative drive and shore power are POA.

$156,706

Equipment total

2×630 kVA S13-M

Transformer

$32,200

SVG dynamic compensation

~3 yr

SH15 upgrade payback

$19,344

Annual losses

161,197 kWh/yr

Loss energy

8 · FAQ

What transformer for a 600 kW terminal?

480 kW ≈ 505 kVA → 630 kVA tier; N+1 uses 2×S13-M-630/10, 80% loading after one-unit loss.

SVG vs plain capacitor compensation?

Capacitors only correct steady-state reactive; SVG responds <10 ms and handles both crane-surge flicker and 42% harmonics — SVG is mandatory here.

Does the crane need a VFD?

Yes — 160 kW on VFD gives 1.7% dip (vs 8.2% DOL), plus smooth start/stop and regenerative braking.

How is 42% THDi handled?

Stacked crane/RTG VFDs push THDi to 42%; use SVG active filtering + detuned reactor, target ≤8%.

What does voltage flicker do?

300 kW crane surge causes bus flicker that can mis-trip adjacent feeders; SVG fast compensation holds the voltage.

Where does crane-lowering regenerative energy go?

A regenerative drive returns braking energy to the DC bus, with a braking resistor to dissipate the excess.

Is a backup source needed?

The grid-tied scheme has no diesel/UPS; N+1 dual transformers give transformer-level redundancy — add backup only for critical continuous duty.

What's the payback on a better transformer?

SH15 amorphous vs S13 saves ≈2,803 kWh/yr ($337/yr), ~3 yr payback.

Is the price final?

No — $156,706 is a feasibility-level estimate; crane regenerative drive and shore power are POA, and grid Ssc must be confirmed.

Special Considerations

THDi 42% is severely over the limit: PFC capacitors can't handle flicker, SVG dynamic compensation is mandatory (V6 remedy).
This scheme is grid-tied with no backup; if cranes are critical continuous duty, evaluate diesel/UPS separately.
Crane regenerative drive and shore power are POA; multi-crane coincidence factor must be verified.
The 160 kW crane VFD is the largest motor; confirm regenerative braking resistor and DC bus rating.
Feasibility-level estimate; drawings pending a licensed design institute; confirm grid Ssc (500 MVA assumed).

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