GB/T 13030.1-2026Technical specification for ship electric propulsion systems — Part 1: AC low voltage (English PDF)

3.1 main source of electrical power

A source that supplies power to the main switchboard and, through the main switchboard, distributes power to all equipment necessary for maintaining the ship in normal operational and habitable conditions.

3.2 emergency source of electrical power

A source that supplies power to the emergency switchboard in the event of failure of the main source of electrical power.

3.3 main switchboard

An assembly of switchgear and controlgear that is directly supplied by the main source of electrical power and distributes and controls electrical energy to various equipment on board.

3.4 emergency switchboard

An assembly of switchgear and controlgear that is normally supplied by the main switchboard, and in the event of failure of the main power supply system, is directly supplied by the emergency source or temporary emergency source, and distributes and controls electrical energy to various emergency equipment.

3.5 distribution board

An assembly of switchgear and controlgear for controlling and distributing electrical energy to final sub-circuits.

3.6 final sub-circuit

The part of the distribution system located downstream of the last overcurrent protective device.

3.7 back-up protection

A protective device or system that operates when the protective device nearest to the fault point is faulty or incapable, or when other protective devices are faulty, such that the system fault cannot be cleared in a timely manner.

3.8 continuity of power supply

The assurance that power supply to non-faulted circuits is maintained during and after a fault in a certain circuit.

3.9 uninterruptible power system (UPS)

A power supply device consisting of a combination of converters, switches and energy storage devices, used to maintain continuity of power supply to loads in the event of input power failure.

Note: Energy storage devices refer to batteries, etc.

3.10 vital equipment

Equipment essential for propulsion, steering and ship safety.

3.11 energy storage system (ESS) for vessel

A device that stores electrical or other forms of energy, capable of providing power or electrical sources to ship loads.

Note: An ESS generally includes the control system of the energy storage device.

3.12 voltage harmonic distortion

The total harmonic distortion (THD) of the voltage waveform is the ratio of the RMS value of the harmonics to the RMS value of the fundamental, expressed as a percentage.

3.13 energy management system (EMS)

An automated system for monitoring, controlling and optimising the distribution and use of electrical energy in a power system.

3.14 propulsion control system

An automated system for monitoring, controlling and protecting the ship's propulsion device.

3.15 insulated gate bipolar transistor (IGBT)

A fully controlled voltage-driven power semiconductor device composed of a field-effect transistor and a bipolar transistor in combination.

3.16 liquefied natural gas (LNG) unit

A general term for a complete set of equipment that uses LNG as fuel, releases thermal energy through combustion and converts it into mechanical or electrical energy.

4.1 Composition

Low-voltage AC electric propulsion generally includes prime movers, generators, excitation devices, main switchboards, power transformers, semiconductor converters, electric motors, propulsors, energy management systems, propulsion control systems, ship energy storage systems, uninterruptible power supplies, etc.

4.2 Power supply parameters