Port RTG Crane VFD Harmonics: Feeder Measurement Plan
Container terminals run RTG cranes whose hoist and gantry VFDs create bursty harmonic current that coincides with vessel working windows. Assessing RTG crane VFD harmonics starts at the crane feeder or quay substation with duty-state labels, not from a quiet-shift snapshot.
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Container terminals run RTG cranes whose hoist and gantry VFDs create bursty harmonic current that coincides with vessel working windows. Assessing RTG crane VFD harmonics starts at the crane feeder or quay substation with duty-state labels, not from a quiet-shift snapshot.
Terminal productivity meetings often collide with power-quality questions. CNBYG can review AHF/APF fit when measured harmonic current is defined. This article does not confirm crane productivity targets, terminal electrification certification, or a guaranteed harmonic result. Browse related guides in the Guías de Ingeniería de Sistemas de Calidad de Energía.
Set the crane-feeder measurement boundary
A logger on an RTG feeder characterizes hoist and gantry duty. A logger at the quay substation or terminal PCC answers a different scope question. Record CT data and how many cranes shared the bus.
For RTG hoist, trolley, and gantry VFD groups on terminal feeders, cover hoist lift, trolley travel, gantry move, idle between moves, and multi-crane coincidence. Note how many RTGs shared the feeder during each window, because coincidence during vessel working peaks can dominate the spectrum.
Un registro previo a la solicitud de cotización (RFQ) práctico para esta aplicación normalmente incluye:
- Single-line of quay substations and RTG feeders.
- Spectra during vessel working peaks, not only idle shifts.
- Notes linked to the crane duty and coincidence state for every export.
- Existing filters and capacitor banks on the quay bus.
- Demand trends across at least one busy vessel window.
| Terminal logging focus | Required attachment | Decisión que respalda |
|---|---|---|
| Activity at the monitored RTG feeder or quay substation | Espectro actual, tendencia RMS, estado de carga, referencia de TC | Caracterización de fuentes locales |
| Actividad en el límite del sistema | Tendencias de voltaje/corriente, datos del transformador y aguas arriba | Alcance de mitigación de límites |
| Repeatability across vessel working and shift cycles | Múltiples ventanas de operación etiquetadas | Planificación de capacidad y puesta en marcha |
| Equipos conectados | Inventario de líneas de distribución, protección y compensación | Revisión de interacción e integración |
Importante: Do not size APF capacity from idle-shift RTG data when the objective covers vessel working peaks (Source: Medición de armónicos de variadores de frecuencia y selección de filtro activo de potencia). Multi-crane coincidence can dominate quay feeders.
Separate crane KPIs from distortion claims
Moves-per-hour and harmonic readings answer different questions. A waveform anomaly does not prove a hoist control fault. Keep scopes and acceptance methods separate.
El Resumen de la norma IEEE 519 helps frame PCC talks; terminals still need local operating cases and contractual language.
Operators should also record hoist versus gantry dominance in each window, because those duty cycles stress different parts of the drive line-up. Keep a short note on which berth and which vessel working window produced each file so terminal and electrical teams can reconcile timestamps during RFQ review. Those notes are short, but they keep quay coincidence windows comparable for quotation.
Shortlist after coincidence evidence exists
Consider AHF/APF when harmonic-current reduction at the terminal medium-voltage or PCC boundary is documented with coincidence notes. SVG may fit reactive swings during gantry moves. Passive options need a quay network study.
| Categoría de mitigación | Útil cuando | Confirmar antes de la cotización |
|---|---|---|
| AHF / APF | Harmonic-current reduction at the terminal medium-voltage or PCC boundary is documented | Espectros, plan de TC, ruta térmica, protección, prueba de aceptación |
| SVG / ASVG | El soporte rápido de potencia reactiva es el objetivo principal | Perfil de tensión, compensación existente, controles, puesta en marcha |
| Sintonización pasiva | Un estudio de sistemas muestra una función sintonizada o desintonizada estable | Revisión de resonancia, política de cambio, acceso de mantenimiento |
| Cambio operativo | Los cambios en la programación o en los turnos modifican materialmente la demanda | Aprobación del propietario e implementación documentada |
Assemble a quay RFQ evidence pack
Before suppliers quote, assemble coincidence-labeled RTG spectra, crane-count tables, CT notes, and a marked-up quay single-line. State whether the decision is local crane troubleshooting, terminal-boundary assessment, or harmonic-current mitigation. Present vessel-peak and idle-shift windows separately.
Require the quote to name covered orders, salt-air enclosure limits, and acceptance tests. Include headroom for additional cranes and list filters already on the quay bus. Assign who records coincidence notes and who signs acceptance after berth tests.
Add salt-air enclosure notes, berth outage windows, and a glossary of crane coincidence codes so vessel-peak files are not mixed with idle-shift exports. Include CT polarity checks, sample intervals, and a note describing how many RTGs shared the feeder during each capture. Record expected spare headroom for additional cranes and keep the acceptance checklist owner named before quotation begins.
Revisar el Página del filtro activo de armónicos CNBYG AHF against coincidence-labeled quay data. The automotive plant guide on Medición de armónicos de variadores de frecuencia y selección de filtro activo de potencia shows how multi-machine coincidence is documented elsewhere.
Integration under terminal constraints
Document salt-air enclosure ratings, cable routes along the quay, and berth outage windows. Acceptance should replay multi-crane windows comparable to the baseline.
The related industrial measurement scenario in Selección de APF y SVG para la fabricación de automóviles shows how coincidence notes support post-install checks.
Terminal inquiry package
Provide single-line drawings, coincidence-labeled spectra, crane counts, compensation inventory, and preferred connection points. CNBYG can discuss fit and should not guarantee crane productivity targets, terminal electrification certification, or a guaranteed harmonic result. Submit via the Página de contacto de CNBYG.
Preguntas frecuentes
Where should RTG crane harmonics be measured first?
Begin at the crane feeder or quay substation serving the working group, then expand to the terminal PCC if the objective is plant-boundary mitigation.
Do multi-crane coincidence windows matter?
Yes. Vessel peaks often stack several RTGs on one bus, so coincidence notes are required for capacity discussions.
Can idle-shift data size an APF for a busy berth?
No. Quiet-shift spectra understate hoist and gantry duty that define peak harmonic demand.
¿Es suficiente una sola medición para seleccionar equipos de mitigación?
Rarely at busy berths. Crane coincidence, vessel windows, and objective definition decide whether the data is representative.
Can mitigation equipment be sized from connected crane kVA alone?
No. Connected kVA is context; measured harmonic stacks and coincidence logs drive capacity review.
¿Este artículo garantiza un resultado operativo o de cumplimiento?
No. Terminal operations, network conditions, and commissioning must be verified on site.