A shore-to-ship power transformer must be specified as part of the complete shore connection. Matching voltage is only one requirement. Frequency, isolation, grounding, converter behavior and ship-network operating states also need coordination. A transformer cannot by itself resolve a frequency mismatch, and a suitable transformer does not establish that the entire shore-power system is compatible.
Define both sides of the connection
Record shore supply voltage and frequency, the ship’s required supply characteristics and the connection architecture. Identify any frequency converter and state whether the transformer is on its input, output or another defined boundary.
IEEE/IEC 80005-1 addresses high-voltage shore-connection systems within its scope. It should not be treated as a universal requirement for every low-voltage connection or cited without checking the edition and amendments applicable to the contract. [1]
Shipboard transformer requirements have their own scope under IEC 60092-303. The shore-side equipment, shipboard equipment and integrated connection need clearly allocated requirements rather than one blanket marine label. [2]
Separate ratio, isolation and frequency functions
A transformer can provide the specified voltage ratio and, where its arrangement provides it, galvanic separation. Frequency conversion is a different function performed by suitable conversion equipment. The transformer waveform duty depends on its location relative to that equipment.
Do not assume that a converter-output transformer sees the same waveform as a shore-input transformer. Request the relevant voltage and current characteristics, including operating modes and any filtering.
| Function | Question to resolve |
|---|---|
| Voltage transformation | Which terminal voltages and operating ranges apply? |
| Frequency conversion | Which equipment establishes the ship-side frequency? |
| Isolation | Where is the required separation provided? |
| Grounding | Which arrangement applies on each side and in each mode? |
| Protection | How are source contributions and fault boundaries coordinated? |
Review connected and transfer states
The operating matrix should identify shore-connected service, connection and disconnection transitions, relevant ship-source states and loss of shore supply. Any intended parallel or transfer operation requires an approved system design; it cannot be inferred from transformer ratings alone.
The transformer duty should include the ship’s coincident load, motor or converter behavior, reactive power and duration. A vessel’s installed connected load is not automatically its shore-supplied maximum demand, but diversity assumptions must be supported by the actual operating arrangement.
Converter-transformer application guidance may be relevant where conversion equipment imposes specialized requirements. Its applicability follows the actual circuit and waveform, not merely the presence of a ship. [3]
Define acceptance across the shore-ship boundary
The enquiry should include the agreed single-line diagram, transformer location, source and load envelopes, grounding philosophy, control interfaces and environmental conditions. Identify which party supplies each study and which party owns integrated acceptance.
Equipment certificates should retain their scope. A shipboard transformer approval is not proof that the port’s cable system, converter and control sequence satisfy the complete connection requirements. Likewise, a shore-side test does not automatically establish compatibility with every visiting vessel.
The useful deliverable is a coordinated interface schedule with supported operating states and explicit limitations. That schedule prevents a technically correct transformer quotation from being mistaken for a complete shore-power solution when frequency conversion, ship compatibility or protection coordination remains unresolved.
Core procurement checkpoint: Separate magnetic design from the shore-connection system
A shore-power transformer core should be specified for the actual voltage and frequency on its side of any converter. A core or lamination quotation does not establish frequency conversion, galvanic-isolation performance of the complete unit, or compliance of the shore connection. Keep the approved core drawing linked to the correct onboard or shore-side equipment design and system boundary.
For the core enquiry: Transformer location and frequency; approved core drawing; material specification; included clamps; complete-system qualification owner.