Section 24 Hybrid electrical power systems

24.1.1 The requirements of this Section are applicable to ships having a main source of electrical power which is provided by hybrid electrical power generation and distribution systems within which the main electrical power demand is supplied by two or more different types of power source or by stored electrical energy.

24.1.2 These requirements apply to the design, construction and integration of hybrid electrical power systems, their sub-systems, machinery and equipment.

24.1.3 These requirements apply to hybrid electrical power systems which provide the main source of electrical power and exceptionally, where permitted by the National Administration, the emergency source of electrical power.

24.1.4 In addition to these requirements National Administrations may impose further requirements. Where such requirements conflict with these requirements, the requirements of the National Administration will take precedence.

24.1.5 These requirements are additional to the applicable requirements of the Rules and Regulations for the Classification of Ships, July 2022.

24.2.1 Ships complying with the mandatory requirements of this Section will be assigned the Hybrid Power machinery special features notation.

24.2.2 Ships complying with both the mandatory requirements and the additional optional requirements of this Section will be assigned the Hybrid Power (+) machinery special features notation.

24.2.3 Hybrid Power: Assigned to ships with an electrical power system including a combination of two or more different types of power source or utilising stored electrical energy to satisfy the ship’s main power demand. The system and its component parts are in accordance with the existing applicable requirements of the Rules and the requirements of Pt 6, Ch 2, 24 Hybrid electrical power systems.

24.2.4 Hybrid Power (+): Assigned to ships meeting the requirements for Hybrid Power and the additional optional requirements for Hybrid Power (+) specified within Pt 6, Ch 2, 24 Hybrid electrical power systems. The additional optional requirements aim to provide for enhanced performance of the electrical power system achieved through the consideration of system simulation, system integration and dependability of the electrical power system during normal or reasonably foreseeable abnormal operation.

24.3.2 Reasonably foreseeable abnormal condition: A reasonably foreseeable abnormal condition is an operation, event, incident or failure that:

1. has happened and could happen again;
2. has not happened but is considered possible. Where the likelihood is considered extremely unlikely or the consequences are trivial, and no further prevention or mitigation action is to be taken, then this is to be justified; and
3. is planned for (e.g. emergency actions cover such a situation, maintenance is undertaken to prevent it).

They should be identified by:

1. using analysis processes that are capable of revealing abnormal conditions;
2. employing a mix of personnel including designers, Operators, persons who carry out maintenance and competent safety/risk professionals with relevant domain knowledge and understanding to apply the processes;
3. referencing relevant events and historic data; and
4. documenting the results of the analysis.

24.3.3 Source of electrical power: A source of electrical power produces electrical power from an energy source such that its output may be connected to ship’s electrical power distribution system (see Figure 2.24.1 Source of electrical power). It includes:

1. Dedicated conversion where conversion is the changing of an output with respect to its input and may include change of form (e.g. a.c. to d.c. or d.c. to a.c.), change in magnitude (e.g. of voltage, current or frequency), change in phase or change in reference (e.g. through galvanic isolation);
2. Management systems perform monitoring, control, protection and safety functions that are likely to be connected to higher level ship wide supervisory systems: and
3. Systems providing control, alarm, monitoring and safety functions such as control panel, governor, automatic voltage regulator (AVR) and emergency shutdown (ESD) system for a reciprocating engine or gas turbine generator.

This definition of source of electrical power is independent of:

1. the type of source (e.g. rotating generator, waste heat recovery system, wind generator, solar panel, fuel cell, photovoltaic array);
2. the type of distribution system (see Pt 6, Ch 2, 24.3 Definitions 24.3.8); and
3. the application of the source (e.g. main/additional/emergency/transitional source of power).

Figure 2.24.1 Source of electrical power

24.3.4 Additional source of electrical power: An additional source of power is a source of electrical power not forming part of the ship’s main source of power that is rated to supply a proportion of the ship’s main power demand at any time either continuously or for an accepted period of time, e.g. an energy storage device or a power take-off that is not rated for or capable of permanent operation.

24.3.5 Store of electrical energy: A store of electrical energy receives, stores and discharges energy through a single point of common coupling with the distribution system (see in Figure 2.24.2 Store of electrical energy). It includes management systems and any required dedicated conversion as defined in Pt 6, Ch 2, 24.3 Definitions 24.3.3.This definition is independent of:

1. the method of energy storage;
2. the type of store (e.g. battery, capacitor);
3. the type of distribution system (see Pt 6, Ch 2, 24.3 Definitions 24.3.8); and
4. the application of the store (e.g. power source, load smoothing, peak shaving, dynamic response, power backup).

Figure 2.24.2 Store of electrical energy

24.3.7 Combined sources/stores/consumers of electrical power: A combined source/store/consumer of electrical power provides multiple functions as defined in Pt 6, Ch 2, 24.3 Definitions 24.3.4 to Pt 6, Ch 2, 24.3 Definitions 24.3.7 in a single functional arrangement (some examples are shown in Figure 2.24.4 Combined source and consumer of electrical power to Figure 2.24.7 Combined store of electrical energy and source and consumer of electrical power). They include management systems and any required dedicated conversion as defined in Pt 6, Ch 2, 24.3 Definitions 24.3.3.

Figure 2.24.4 Combined source and consumer of electrical power to Figure 2.24.7 Combined store of electrical energy and source and consumer of electrical power depict building blocks that may be encountered in a hybrid electrical power system. These do not represent complete systems, are provided for illustration purposes only and are not exhaustive with further permutations being viable.

Figure 2.24.4 Combined source and consumer of electrical power

Figure 2.24.5 Combined source of electrical power and store of electrical energy

Figure 2.24.6 Combined store of electrical energy and consumer of electrical power

Figure 2.24.7 Combined store of electrical energy and source and consumer of electrical power

24.3.8 Distribution system: The distribution system provides the interconnection between, protection of and isolation of:

• sources (see Pt 6, Ch 2, 24.3 Definitions 24.3.3 to Pt 6, Ch 2, 24.3 Definitions 24.3.4),
• stores (see Pt 6, Ch 2, 24.3 Definitions 24.3.5),
• consumers (see Pt 6, Ch 2, 24.3 Definitions 24.3.7) and
• combinations thereof (see Pt 6, Ch 2, 24.3 Definitions 24.3.7).

It includes management systems (e.g. power management) and any required dedicated conversion as described in Pt 6, Ch 2, 24.3 Definitions 24.3.3. There are no constraints on its type (e.g. a.c. or d.c.), magnitude (e.g. voltage and/or frequency), nature (e.g. fixed or variable), architecture (e.g. tree, radial, zonal), physical form or on the number of variants within a ship.

24.3.9 Energy management: Energy management functionality provides the overall control, monitoring, protection and safety functions that are necessary to deliver dependable electrical power from the hybrid electrical power system in all operating modes and under both normal and reasonably foreseeable abnormal conditions. It comprises supervisory functions that integrate the management systems of the components (sources, stores, consumers, distribution systems) from which the hybrid system is constructed and may be implemented as a stand-alone system or as distributed functionality across a number of systems.

Energy management is focused on energy flow and is typically model based, predictive in nature, inclusive of optimisation functionality and employing the principles of health and condition monitoring at system level (e.g. as described in ShipRight Procedure for the Approval of Digital Health Management Systems).

Energy management functionality is considered additional to the functionality of a conventional power management system as described in IEC 60092-504, Electrical installations in ships, Part 504: Automation, control and instrumentation, Section 9.4.

24.3.10 Power system integration: Power system integration comprises those system level activities that are required to be undertaken to design and develop, build and then operate and maintain safely through life a dependable ship’s hybrid electrical power system including its constituent components (shown pictorially in Figure 2.24.8 Role of system integration activities). At each phase of a project power system integration is managed by a single designated party and is carried out in accordance with a defined procedure identifying the roles, responsibilities and requirements for all parties involved.

Figure 2.24.8 Role of system integration activities

24.3.11 Dependability: Dependability is as defined in IEC 60050(191), Quality vocabulary – Part 3: Availability, reliability and maintainability terms – Section 3.2: Glossary of international terms. It is the collective term used to describe the availability performance and its influencing factors: reliability performance, maintainability performance and maintenance support performance as agreed with LR.

24.4.1 To provide sufficient electrical power of appropriate dependability to supply the required essential services, habitability requirements and those services required to maintain the ship in a normal sea-going and operational state during defined operational conditions without recourse to the emergency electrical supply.

24.4.2 Damage and injury: To provide electrical systems and equipment with suitable protection under fault conditions to prevent the following:

1. injury to onboard personnel;
2. damage to the equipment itself; and
3. damage to equipment connected to it.

24.4.3 On ships with electric propulsion, to provide sufficient electrical power necessary for an effective and agreed level of propulsion power during all normal and reasonably foreseeable abnormal operational conditions.

24.5.1 For Hybrid Power notation the performance of the system is to be such that in the event of a single failure operation of the system may be interrupted but is to be recoverable to a defined state bounded by time and magnitude.

24.5.2 For Hybrid Power (+) notation the performance of the system is to be such that in the event of a single failure operation of the system is to be uninterrupted with any degradation of performance agreed between the designers and Owners.

24.5.3 The hybrid electrical power system performance targets in all modes of operation are to be defined and agreed between the designers and Owners.

24.5.4 The electrical system design maximum and minimum operating voltage and input frequency together with acceptable limits of excursions are to be specified by the system designer and are to be in compliance with the requirements of the Rules.

24.5.5 Specific consideration is to be given to time-based performance targets for systems in which stored electrical energy supplies any part of the ship’s main power demand.

24.5.6 Methods of verification of actual performance against targets are to be defined and are to cover all phases of the lifecycle.

24.6.1 The hybrid electrical power system dependability principles are to be defined and agreed between the designers and Owners consistent with the requirements for Hybrid Power or Hybrid Power (+) notation.

24.6.2 The principles are to cover defined operating modes, all normal and reasonably foreseeable abnormal operating and fault conditions and are to specifically consider the fault ride-through capability of the system.

24.6.3 The principles are to cover failures in active components of any of the sources, stores, consumers, distribution system and energy management forming the hybrid electrical power system. Such components may include, but are not restricted to, the following:

1. Prime movers (e.g. auxiliary engines);
2. Generators and their excitation equipment;
3. Gearing;
4. Pumps;
5. Fans;
6. Switchgear and controlgear, including their assemblies;
7. Thrusters; and
8. Valves (where power actuated).

24.6.4 Consideration is to be given to other enabling systems not part of the hybrid electrical power system whose failure or degradation could affect correct functioning of the hybrid electrical power system (e.g. lubrication, cooling and ventilation systems).

24.6.5 The continuity of supply to essential and emergency safety systems is to be maintained, in accordance with Pt 6, Ch 2, 2 Main source of electrical power.

24.6.6 Arrangements are to ensure that the supply of essential services is not disrupted by the unavailability of the largest source of electrical power and are to be in accordance with a clearly described, documented and agreed redundancy design intent.

24.6.7 The size and rating of electrical energy stores is to be appropriate for the specified lifetime when subjected to in-service cyclic loading. Calculations supporting this assessment are to be provided to LR.

24.6.8 For Hybrid Power (+) a hybrid electrical power system dependability assessment is to be undertaken and submitted to LR. The objectives of the assessment are to:

• demonstrate the dependability of the system during all normal and reasonably foreseeable abnormal conditions; and
• demonstrate that an appropriate level of dependability is achieved that is commensurate with that agreed between the designers and Owners.

The assessment shall be undertaken to a recognised standard that is acceptable to LR (e.g. IEC 60300-3-1, Dependability management Part 3-1: Application guide – Analysis techniques for dependability – Guide on methodology).

24.7.1 The main source of electrical power is to comply with the requirements of Pt 6, Ch 2, 2 Main source of electrical power.

24.7.2 Any type of source of electrical power as detailed in these hybrid electrical power system Rules may, subject to the approval of LR, be considered as having equivalent function to that of a generating set as described in, but not limited to, Pt 6, Ch 2, 2 Main source of electrical power.

24.7.3 Sources of electrical power not forming part of the ship's main source of electrical power may be used as an additional source of electrical power to supply electrical services required for normal operational and habitable conditions provided that:

1. The quality of power supplies meets the requirements of Pt 6, Ch 2, 24.17 Transversal requirements 24.17.3; and
2. Automatic arrangements are provided to start and connect within a period not exceeding 45 seconds one of the sources forming the main source of electrical power in the event of a single failure or the quality of power supplies exceeding limits.

24.8.1 The emergency source of electrical power is to comply with the requirements of Pt 6, Ch 2, 3 Emergency source of electrical power.

24.8.2 For ships with a specified service notation as defined in Pt 1, Ch 2, 2.3 Class notations (hull), where it is proposed that a dedicated emergency source of electrical power and its associated transitional source of power will not be provided, the main source of electrical power and associated equipment is to meet the following requirements:

1. Sources providing the main source of electrical power are to be:
   1. separated and located in two or more compartments that are not contiguous with each other;
   2. self-contained and arranged to be independent such that each system can operate without recourse to the other main source(s) including power distribution and any associated auxiliary and ancillary converting equipment and control systems;
   3. arranged such that a fire, flood or casualty in any one of the compartments will not affect the electrical power distribution from the other(s), or to the services required by Pt 6, Ch 2, 3 Emergency source of electrical power;
   4. capable of being started automatically on loss of the power supplied by the other main source(s) of electrical power and supplying the essential services as quickly as is safe and practicable subject to a maximum of 45 seconds, or provided with a transitional source of emergency electrical power;
   5. arranged to allow for maintenance at sea of any one source without affecting the ability to comply with these requirements; and
   6. provided with starting arrangements compliant with the requirements of Pt 5, Ch 2, 9.5 Starting of the emergency source of power.
2. Where these Rules specify that a service is required to be connected to both the main and emergency source of electrical power or is to be connected to the emergency switchboard, then these services are to be served by at least two individual circuits from the separated main sources of electrical power with arrangements to transfer between the two sources. The supplies are to be separated in their switchboard and throughout their length as widely as is practicable without the use of common feeders, protective devices, control circuits or controlgear assemblies so that any single fault will not cause the loss of both supplies.
3. Provision is to be made for periodic testing to demonstrate services required by Pt 6, Ch 2, 3 Emergency source of electrical power can be supplied automatically following the loss of one main source of electrical power.
4. To demonstrate compliance with these requirements a risk assessment of the electrical, mechanical, piping arrangements, cooling arrangements and any other sub-systems whose failure or degradation could have an impact on the performance of the system is to be carried out demonstrating that a single point failure such as a fire or flooding within a space would not render the systems incapable of supplying those services required in an emergency or other reasonably foreseeable abnormal event. The assessment is to be undertaken to a recognised standard that is acceptable to LR (e.g. ISO 31010, Risk management – Risk assessment techniques) and in accordance with ShipRight Procedure Risk Based Certification (RBC) .

24.9.1 Ships utilising an external source of power are to comply with the requirements of Pt 6, Ch 2, 4 External source of electrical power.

24.9.2 Arrangements for d.c. external sources are to comply with a recognised standard that is acceptable to LR.

24.9.3 Onshore power supplies and their connection are to comply with Pt 7, Ch 13 On-shore Power Supplies.

24.9.4 Ships using an external source of power to charge onboard stores of electrical energy will be specifically considered by LR. Details of the arrangements and their interfaces to ship systems are to be submitted.

24.10.1 Ships with electric propulsion are to comply with the relevant power requirements of Pt 6, Ch 2, 16.3 Power requirements.

24.10.2 Ships with electrically driven azimuthing thrusters are to comply with the relevant power requirements of Pt 5, Ch 20, 5.2 Generating arrangements 5.2.2.

24.10.3 Ships with dynamic positioning systems are to comply with the relevant power requirements of Pt 7, Ch 4 Dynamic Positioning Systems

24.10.4 Passenger ships are to comply with the relevant power requirements of Pt 5, Ch 23 Additional Requirements for Passenger Ships and the ShipRight Procedure for Assigning the SRtP Descriptive Note.

24.10.5 Ships with optional notations for propulsion and steering redundancy are to comply with the relevant power requirements of Pt 5, Ch 22, 3.3 Electrical power supply.

24.10.6 Ships with the optional notation for integrated propulsion systems are to comply with the relevant power requirements of Pt 5, Ch 18, 2 Machinery arrangements.

24.11.1 The main source of electrical power is to comply with the requirements of Pt 6, Ch 2, 2 Main source of electrical power.

24.11.2 The emergency source of electrical power is to comply with the requirements of Pt 6, Ch 2, 3 Emergency source of electrical power.

24.11.3 External sources of electrical power are to comply with the requirements of Pt 6, Ch 2, 4 External source of electrical power.

24.11.4 Additional sources of electrical power as defined in Pt 6, Ch 2, 24.3 Definitions 24.3.4 are to comply with the requirements of this Chapter.

24.11.5 Rotating electrical generators within sources of electrical power are to comply with the requirements of Pt 6, Ch 2, 9 Rotating machines.

24.11.6 Converters within power sources are to comply with Pt 6, Ch 2, 10.2 Semiconductor converters and the following requirements:

1. Converters are to be selected to withstand the voltage ripple levels present on the distribution system. For every system, the following voltage parameters are to be defined:
   1. maximum non-repetitive peak;
   2. maximum repetitive peak; and
   3. maximum repetitive peak-to-peak.
2. Where pulse width modulation converters are to be used, the voltage rate of rise times are to be determined, the results recorded and submitted to LR. Rotating machinery, surge protective devices, cable insulation and motor windings are to be designed accordingly.
3. Converters may be of conversion type a.c./a.c., d.c./a.c., a.c./d.c., d.c./d.c., and of the controlled (e.g. active front end (AFE)) or non-controlled type (e.g. diode supply unit (DSU)).
4. Converters are to be provided with visual status indication at their associated control stations to include, but not be limited to:
   1. Power available at the input;
   2. Power at output;
   3. Temperature; and
   4. Overload.

   If certain indicators and alerts are not applicable, sufficient evidence to support the claim is to be submitted for consideration by LR. Additional indicators, alerts and shutdowns may be necessary as determined through the system Failure Modes and Effects Analysis (FMEA) required by Pt 6, Ch 2, 24.27 Power system development and integration - System Failure Modes and Effects Analysis (FMEA).

5. Converters supplying electrical power to the distribution system and consumers are to be capable of delivering the required currents for the time required to enable current-time discrimination of protective devices to operate. The electrical output of the converter is to be automatically restored following fault clearance.
6. Converter software is to satisfy the requirements of Pt 6, Ch 1, 2 Essential features for control, alarm, monitoring and safety systems
7. Converters are to be capable of handling voltage and current spikes from the distribution system under all normal and reasonably foreseeable abnormal conditions without sustaining any damage or tripping.
8. Converters supplying essential services are to automatically restart and connect to the distribution system after a blackout as specified in Pt 6, Ch 2, 2.2 Number and rating of generators and converting equipment.
9. Where converters are equipped with internal capacitors which can contribute significantly to the short-circuit level of the system, the contribution is to be included in the design of the protection and distribution system.
10. The risk of converter component damage due to inrush currents is to be minimised by appropriate management of these currents during transient events and after short circuit.
11. Where capacitors are connected to a converter output, the output is to be charged by the converter or by external chargers to a level which will minimise the risk of damage to the capacitors before connecting them to the distribution system.
12. Converters arranged to operate in parallel are to be capable of stable load sharing up to maximum continuous load and inclusive of any temporary overloads within their design rating.
13. Where converters are arranged to provide protection against electrical faults a disconnector or switch disconnector is to be provided to enable safe isolation of the converter from its incoming supplies.
14. Converters are to be protected from permanent physical damage as a result of short circuits or overload currents on their input and output terminals.
15. Converters are to have a ride-through capability to manage system transients including the effects of fault clearance in the distribution system that is consistent with the dependability requirements of the system.
16. Converters are to be provided with appropriate filters to ensure the required quality of power supply at both their input and output. In the event of filter circuit failure, continued safe operation of the hybrid electrical power system is to be possible by following specified procedures as described in operation procedures. These procedures are to include any operational limitations, and they are to be kept on board, maintained in accordance with Pt 6, Ch 2, 24.18 Power system development and integration - General 24.18.3 and made available to the Surveyor on request.

24.12.1 Functional requirements: To provide sufficient stored electrical energy as a component of the main source of power to supply services during normal and reasonably foreseeable abnormal and emergency conditions.

24.12.2 Batteries of the vented and valve-regulated sealed type and lithium batteries are to comply with Pt 6, Ch 2, 12 Batteries.

24.12.3 Power converters within stores of electrical energy as illustrated in Pt 6, Ch 2, 24.3 Definitions 24.3.5 are to comply with the relevant requirements of Pt 6, Ch 2, 24.11 Hybrid electrical power system components - Source of electrical power 24.11.6.

24.12.4 For consideration as a component of the main source of power on a ship with a specified service notation as defined in Pt 1, Ch 2, 2.3 Class notations (hull) and subject to approval of the National Administration a store of electrical energy is to:

1. Comply with Pt 6, Ch 2, 24.7 Hybrid electrical power system performance - Main source of electrical power;
2. Have a minimum capacity at any stage of its lifecycle sufficient for its contribution to the main source of power that is necessary to achieve the specified service requirements;
3. Be provided via energy management functionality with remote indication of state of charge (available capacity in a store expressed as a percentage of rated capacity) and state of health (general condition of a store expressed as a percentage of its ability to deliver the specified performance compared with that of a new store);
4. Have a primary purpose of supplying the ship’s main power demand. Details of any secondary purpose including but not limited to optimising performance (e.g. load smoothing, peak shaving), improving stability (e.g. dynamic response) or providing transitional power are to be provided to LR; and
5. Be capable of being restored from a dead-ship condition with no dependence on other systems or electrical supplies. Details of alternative arrangements may be submitted for consideration by LR.

24.12.5 For consideration as an additional source of power a store of electrical energy is to:

1. Comply with Pt 6, Ch 2, 24.7 Hybrid electrical power system performance - Main source of electrical power 24.7.3;
2. Be provided via energy management functionality with remote indication of state of charge (available capacity in a store expressed as a percentage of rated capacity) and state of health (general condition of a store expressed as a percentage of its ability to deliver the specified performance compared with that of a new store); and
3. Have a primary purpose of supplying the ship’s main power demand. Details of any secondary purpose including but not limited to optimising performance (e.g. load smoothing, peak shaving), improving stability (e.g. dynamic response) or providing transitional power are to be provided to LR.

24.12.6 For application as an emergency source of power a store of electrical energy is to comply with Pt 6, Ch 2, 24.8 Hybrid electrical power system performance - Emergency source of electrical power

24.12.7 Electrical energy storage devices connected to and charged by the distribution system are to be protected against the defined effects of electrical faults in the system.

24.12.8 Energy stores connected to and charged by the distribution system are to be so located and provided with arrangements allowing for the safe isolation of their terminals and the reduction of voltages to a safe level during maintenance or provided with alternative arrangements providing an equivalent level of safety which will be subject to special consideration.

24.12.9 Energy stores are to be connected to the distribution system by protection devices which include but are not limited to overcurrent and short circuit protection. The protective devices used are to be selective, ensuring faults are not transmitted further, independent of the direction of current flow.

24.13.1 Functional requirements: To convert electrical power supplied from the hybrid power generation and distribution system into useful work.

24.13.2 Rotating machines within consumers of electrical power are to comply with the requirements of Pt 6, Ch 2, 9 Rotating machines.

24.13.3 Converters within consumers of electrical power are to comply with the relevant requirements of Pt 6, Ch 2, 24.11 Hybrid electrical power system components - Source of electrical power 24.11.6.

24.13.4 Where a converter is arranged to step down voltage to provide a lower voltage supply to consumers than that of the power system, then arrangements are to be provided to ensure the lower voltage distribution consumers are not subjected to voltage variations, including fast transients, outside their safe operating regions.

24.13.5 Consumers employing loads characterised by constant power characteristics connected to the distribution system through a converter are to be evaluated with respect to ensuring the stability of the power system as part of the power system analysis detailed in Pt 6, Ch 2, 24.24 Power system development and integration - Power system analysis.

24.14.1 Functional requirements: To provide the combined functional requirements of each of the elements (sources, stores, consumers) from which the combination is constructed.

24.14.2 Where a single functional or physical assembly contains a combination of source, store or consume functions, then it is to comply with the requirements of each applicable function as detailed in Pt 6, Ch 2, 24.11 Hybrid electrical power system components - Source of electrical power to Pt 6, Ch 2, 24.13 Hybrid electrical power system components - Consumer of electrical power.

24.15.1 Functional requirements:

1. To provide a dependable interconnection between sources, stores and consumers of electrical power; and
2. To distribute electrical power safely to consumers.

24.15.2 Arrangements for isolation and switching are to be provided which are to enable safe isolation of faults and for maintenance.

24.15.3 Distribution systems supplying consumers through converters are to provide galvanic isolation and ground separation.

24.15.4 In addition to the requirements of Pt 6, Ch 2, 5.3 Isolation and switching, systems are to comply with the requirements of Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.5 to Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.13.

24.15.5 Where consumers are supplied via converters which are connected to both sides of a distribution system that is capable of being split, arrangements are to be provided to eliminate the risk of current being supplied back to the distribution system for example through flyback diodes.

24.15.6 Converters connecting sources, stores and consumers connected to the distribution system are to facilitate the connection and removal of sources, stores and consumers in a stable manner with the electrical power system in operation.

24.15.7 Converters are to be designed to prevent damage to the converter when switching under load.

24.15.8 Where essential services are required by Pt 5 Main and Auxiliary Machinery to be duplicated, these are to be served by individual circuits, separated in their switchboard or section board and throughout their length as widely as is practicable without the use of common feeders, protective devices, control circuits or controlgear assemblies, so that any single fault will not cause the loss of both services.

24.15.9 The distribution system is to be split into at least two independent systems each capable of independent operation or is to be separated by protection devices that are selective, ensuring faults are not transmitted further, and operate independent of the direction of current flow.

24.15.10 The distribution system is to be protected against electrical faults including short circuit, overload, earth fault, differential current, under/over voltage, under/over frequency, power quality, current and voltage imbalance and arc fault in compliance with the relevant requirements of Pt 6, Ch 2, 6 System design – Protection and Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.11 to Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.14.

24.15.11 Active components may be used for the limitation of fault currents subject to verification in a real environment of the performance of the component under all normal and reasonably foreseeable abnormal operating and fault conditions and subject to establishment of effective surveillance and periodic test procedures during operation and maintenance in the ship’s operating manuals to verify the component is capable of performing its intended function. An isolation device is to be provided within the component and this is to be tripped automatically in the event of the component operating. A risk assessment of the component is to be undertaken to a recognised standard that is acceptable to LR (e.g. ISO 31010, Risk management – Risk assessment techniques) and in accordance with ShipRight Procedure Risk Based Certification (RBC).

24.15.12 Where energy management functionality provides protection against incorrect or unexpected energy flows between the sources, stores and consumers forming part of the hybrid electrical power system the sensors used for this purpose in the distribution system are to be independent of those used for control, monitoring and safety systems.

24.15.13 Where a bi-directional flow of power may occur, the distribution system is to withstand the power variations being introduced. The level of bi-directional flow allowed is to be specified by the system designer.

24.15.14 For Hybrid Power (+) notation facilities are to be provided for automatic detection of the location of insulation breakdown with respect to earth of equipment and distribution systems to a level determined by the integrator consistent with the system’s dependability targets and agreed with the designers and Owners.

24.15.15 For either notation, switchgear and controlgear are to comply with the relevant requirements of Pt 6, Ch 2, 7 Switchgear and controlgear assemblies.

24.15.16 Power converters within distribution systems are to comply with the relevant requirements of Pt 6, Ch 2, 24.11 Hybrid electrical power system components - Source of electrical power 24.11.6.

24.15.17 Where fuses are implemented to limit the fault current in the converter, the activation of the protection is not to influence redundant consumers or cause loss of other single consumers as required by Pt 6, Ch 2, 5.2 Essential services.

24.15.18 Fuses used to protect distribution converters are to be of the bolted type. Where alternative arrangements are proposed, it is to be demonstrated that protection system’s selectivity is not adversely affected as a result of an increased connection resistance.

24.15.19 For each section of a d.c. bus there is to be at least one voltmeter per section. An ammeter is to be provided for each converter supplying a d.c. bus. Similar arrangements are to be provided for screen-based displays.

24.15.20 The meters required by Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.19 are to be located and arranged such that they may be viewed at a single operating position. In addition, meters may be required at additional locations to mitigate hazards identified by the risk assessment required by Pt 6, Ch 2, 24.27 Power system development and integration - System Failure Modes and Effects Analysis (FMEA).

24.15.21 Power quality assessments are to consider the detection and impacts of circulating currents such as may exist through capacitive coupling in semiconductor converters.

24.15.22 Constant current distribution systems will be subject to special consideration and are not covered by these Rules.

24.15.23 For Hybrid Power (+) notation warnings of degrading power quality are to be provided and in the event of power quality exceeding prescribed limits automatic isolation and reconfiguration of the power system is to occur as agreed between the designers and Owners.

24.16.1 Functional requirements:

1. To ensure that sufficient energy is available to satisfy the main power demand under all foreseeable operational conditions.
2. To inform Operators as soon as reasonably practicable of deviations from normal operation of the hybrid electrical power system under all normal and reasonably foreseeable abnormal operational conditions.
3. To initiate immediate corrective action on detection of component faults in the hybrid electrical power system that present a danger, reducing the risk to a level that is acceptable to LR.
4. To provide functionality beyond the scope of conventional power management that is necessary for the control, monitoring, protection and dependability of the hybrid electrical power system.

24.16.2 Programmable electronic systems used to provide energy management functionality, or to provide safety functions, are to have arrangements which satisfy the applicable requirements of Pt 6, Ch 1, 2 Essential features for control, alarm, monitoring and safety systems .

24.16.3 Proposed modifications to software, including parameter changes, and during acceptance testing and trials are to be in accordance with Pt 6, Ch 1, 1.5 Alterations and additions as applicable.

24.16.4 Loss of energy management functionality is not to compromise the supply of main power, the safety of the ship, the hybrid electrical power system, or its components.

24.16.5 Energy management functionality is to include, but not be limited to, the following:

1. Control (of the complete system and of each of its sub-systems):
   1. Hybrid electrical power system operating mode selection and transition;
   2. Connection and disconnection of sources, stores and consumers to the distribution system in response to operating conditions and prevailing loads;
   3. Connection and disconnection of distribution system sections;
   4. Load allocation to and sharing between sources;
   5. Load restriction of consumers;
   6. Energy flow management;
   7. Distribution system a.c. voltage and frequency and d.c. voltage; and
   8. Control functions required by sources, stores, consumers or distribution system that are necessary for their operation under all reasonably foreseeable normal, abnormal and fault conditions.
2. Alarm and monitoring:
   1. Mode transition status;
   2. Connection status of sources, stores, consumers and distribution system sections;
   3. Energy flows within the hybrid electrical power system and between its constituent parts;
   4. Power quality as detailed in Pt 6, Ch 2, 24.17 Transversal requirements 24.17.3; and
   5. For stores, state of charge and state of health as defined in Pt 6, Ch 2, 24.12 Hybrid electrical power system components - Store of electrical energy 24.12.4 and Pt 6, Ch 2, 24.12 Hybrid electrical power system components - Store of electrical energy 24.12.5.
3. Protection and safety:
   1. Blackout prevention;
   2. Blackout recovery;
   3. Detection of abnormal or unexpected energy flow as described in Pt 6, Ch 2, 24.15 Hybrid electrical power system components - Distribution system 24.15.13; and
   4. Safety functions required by sources, stores, consumers or distribution system that are necessary for their safe operation.

24.16.6 Overall ship-wide energy management functionality is to be integrated and coordinated with the functionality of the local management systems as described in Pt 6, Ch 2, 24.3 Definitions for each of the components (sources, stores, consumers, combinations, distribution system) of the hybrid electrical power system and is to ensure safe operation of the ship under all normal and reasonably foreseeable abnormal operating and fault conditions.

24.16.7 Additional energy management functionality for Hybrid Power (+) notation is to consider, but not be limited to, the following. The level of functionality supplied is to be consistent with the enhanced performance and dependability required by the system.

1. Control (of the complete system and of each divisible element):
   1. Automatic configuration of the power system based on predicted energy flow;
   2. Automatic system isolation and reconfiguration such that, in the event of a single failure in electrical power sources, stores, distribution system or associated control systems, the impact on the operational performance of the ship is as agreed with LR and there is no impact on the ship’s ability to complete its mission;
   3. System performance optimisation, independent of primary control functions covering emissions, efficiency, availability, reliability or operating cost; and
   4. Control of stores with load smoothing, peak shaving, dynamic response or other optimisation capability.
2. Alarm and monitoring:
   1. Degradation of power quality;
   2. Remaining time for continued operation of the power system at current operating conditions and levels of power consumption. This may take the form of a real-time performance capability plot;
   3. System performance covering energy consumption, emissions, efficiency, availability, reliability or operating cost; and
   4. Health and condition of hybrid electrical power system components including the effects of ageing on electrical energy storage devices.
3. Protection and safety:
   1. Automatic isolation and reconfiguration of the power system on detection of abnormal energy flow;
   2. Consequence analysis determining the remaining time for continued operation of the power system under stated operating and load conditions following the most significant single failure. This may take the form of an onboard off-line simulation derived from, or an integral element of, the simulation described in Pt 6, Ch 2, 24.23 Power system development and integration - Energy flows 24.23.3; and
   3. Automatic detection of faults detailed in the system level FMEA with display of mitigating actions.

24.16.8 A description of functionality including also any functions not described in Pt 6, Ch 2, 24.16 Hybrid electrical power system components - Energy management 24.16.5 and Pt 6, Ch 2, 24.16 Hybrid electrical power system components - Energy management 24.16.7 is to be submitted.

24.17.1 All electrical equipment is to prevent injury to personnel or damage to other equipment and is to be suitably protected against damage to itself under normal, reasonably foreseeable abnormal and fault conditions.

24.17.2 The supply of electrical power sufficient for the correct operation of electrical services for essential equipment and habitable conditions is to be maintained:

1. during all normal and reasonably foreseeable abnormal operating and fault conditions;
2. irrespective of the direction of the propulsion shaft rotation; and
3. without any requirement to revert to emergency supplies.

during all normal and reasonably foreseeable abnormal operating and fault conditions.

24.17.4 A.c. and d.c. systems are during all normal and reasonably foreseeable abnormal operating and fault conditions to provide a quality of power as required by a recognised National or International Standard specified by the power system integrator that is acceptable to LR.

24.17.5 All components of, or connected to, the distribution system are to be designed and validated for operation across the full range of power quality conditions detailed in Pt 6, Ch 2, 24.17 Transversal requirements 24.17.2 to Pt 6, Ch 2, 24.17 Transversal requirements 24.17.4.

24.17.6 The key parameters of power quality as determined by the system integrator with agreement of the Owner and as applicable to the type of electrical power system are to be monitored and recorded for each individually operable section of the distribution system. An alarm is to be raised at a monitored operating station in the event of power quality exceeding limits determined by the system integrator in compliance with the power quality requirements of the Rules. A description of the arrangements provided is to be submitted.

24.17.7 For either notation, all electrical equipment is to comply with the requirements of Pt 6, Ch 2 Electrical Engineering including:

1. General requirements - Pt 6, Ch 2, 1 General requirements including fire, electric shock, ignition, radiation and environment;
2. Creepage and clearance - Pt 6, Ch 2, 7.5 Creepage and clearance distances;
3. Arc - Pt 6, Ch 2, 8 Protection from electric arc hazards within electrical equipment; and
4. Explosive atmospheres - Pt 6, Ch 2, 14 Electrical equipment for use in explosive gas atmospheres or in the presence of combustible dusts.

24.17.8 The choice of materials and components of construction, as well as the design, location and ship installation, are to be made according to the environmental, maintenance and operating conditions in order to maintain the continued function of the equipment during all normal and reasonably foreseeable abnormal conditions and to reduce the risk of:

• injury to onboard personnel;
• damage to the equipment the system is contained within or adjacent equipment and systems;
• damage to adjacent equipment and systems; and
• damage to the ship.

24.17.9 Where applicable, equipment and components are to be selected from the list of LR type approved products satisfying the requirements of Pt 6, Ch 1, 1.4 Control, alarm and safety equipment and Pt 6, Ch 1, 2.13 Programmable electronic systems - Additional requirements for essential services and safety critical systems.

24.17.10  Electrical equipment is to be used within its designed operating parameters, such as current, voltage, power, charging rate, energy storage, etc. to prevent:

1. a hazard occurring; and
2. the equipment affecting safety functions.

24.17.11 All electrical equipment supplied from the main and emergency sources of electrical power and electrical equipment for essential and emergency services is to be selected to operate satisfactorily under the variations of voltage and ripple frequencies which may be present in the system.

24.17.12 Cables and busbars are to be selected and installed in accordance with Pt 6, Ch 2, 11 Electric cables, optical fibre cables and busbar trunking systems (busways).

24.17.13 Transformers within the hybrid electrical power system are to comply with the relevant requirements of Pt 6, Ch 2, 10.1 Transformers.

24.17.14  Interlocks or an alternative acceptable to LR are to be provided which will prevent access to capacitors until their voltage level has reduced to below the safe extra low voltage level (50 V); this is to ensure safety of personnel during maintenance.

24.18.1 The activities specified in Pt 6, Ch 2, 24.19 Power system development and integration - System operational concept to Pt 6, Ch 2, 24.31 Verification requirements are to be undertaken to deliver and maintain a safe and dependable hybrid electrical power system throughout its development, detail design, construction, integration, verification and acceptance. Procedures are to be made available detailing how these activities will be maintained during ship operation, maintenance and disposal.

24.18.2 The activities should be based on the principles of the following five levels with measures adopted at each level being, as far as practicable, independent of each other:

1. Prevention of abnormal operation and failures though design and high quality in construction, operating rules and normal operating procedures;
2. Control of abnormal operation and detection of failures through control, limiting and protection systems, monitoring/surveillance features and abnormal/emergency operating procedures;
3. Control of hazards within the system design to protect against escalation to an incident or accident through engineered safety features and emergency operating procedures;
4. In support of and coordinated by the Owner and ship designer, control of severe ship or infrastructure conditions that may exceed the system design intent including prevention of hazard progression and mitigation of hazardous consequences through complementary procedures and hazard management; and
5. In support of and coordinated by the Owner and ship designer, mitigation of accident consequences through emergency response.

The system designer is to ensure adoption of principles (a) to (c) during the development and integration of the hybrid electrical power system providing evidence to LR through the documentation that is submitted for design review as detailed in Pt 6, Ch 2, 1.2 Documentation required for design review 1.2.18.

24.18.3 At each phase of a project integration activities are to be managed by a suitably competent single designated party and are to be carried out in accordance with a defined procedure identifying the roles, responsibilities and requirements of all parties involved.

24.18.4 Where the designated party changes during a project, then there is to be a full and auditable transfer of necessary integration information between the parties.

24.18.5 Systems engineering processes are to comply with ISO 15288 Systems and Software Engineering – System Life Cycle Processes or an acceptable equivalent National or International Standard.

24.19.1 The system operational concept is to be defined including a description of how the control, alarm and safety systems for the hybrid electrical power system provide effective means for operation and control during all defined ship operational conditions.

24.19.2 The system operational concept is to detail the capability, functionality and modes of operation under defined operating and emergency conditions and is to be agreed between the designers and Owners.

24.19.3 The system operational concept is to be submitted for design review.

24.20.1 Operating modes for the hybrid electrical power system are to be defined and agreed between the designers and Owners.

24.20.2 Modes are to cover all normal and reasonably foreseeable abnormal operating and fault conditions.

24.20.3 Modes are to be compatible with the ship’s overall operating modes.

24.20.4 The sequence of transition between operating modes is to be defined for all reasonably foreseeable normal and abnormal operating and fault conditions.

24.20.5 A technical description is to be produced specifying for each of the ship’s possible operating modes:

1. the type of each electrical power source used to supply the distribution system, such as a.c. generators, d.c. generators, converter, batteries, fuel cells and photovoltaics;
2. the operating mode of each electrical power source such as constant voltage, constant current or variable voltage;
3. the configuration of the electrical distribution system, including the earthing and protection strategies to be used; and
4. the worst-case failure design intent.

24.21.1 Consumers supplied with electrical power from the hybrid electrical power system are to be categorised according to their function and the services that they provide in accordance with the requirements of Pt 6, Ch 2, 1.6 Definitions.

24.22.1 The specifications for all components of the hybrid electrical power system (sources, stores, consumers, distribution system, energy management) are to be validated by the system designer for completeness and correctness in respect of the component’s integration into the overall power system. Validated specifications are to be submitted to LR.

24.22.2 Details of the following are to be specified:

1. Operating modes and the transition between them;
2. Control and monitoring functions;
3. Mechanical components which might affect the hybrid notation (e.g. cooling units with piping arrangements, pumps, valves, etc.);
4. Safety functions;
5. Failure modes;
6. Isolation;
7. Initial and through-life verification of conformance; and
8. Human element.

24.23.1 Energy flows within the hybrid electrical power system are to be determined for all operating modes and all normal and reasonably foreseeable abnormal operating and fault conditions.

24.23.2 The impact of transition between modes on energy flow is to be considered.

24.23.3 For Hybrid Power (+) notation energy flow is to be modelled by a dynamic simulation that can be exercised under normal, reasonably foreseeable abnormal operating and fault conditions and that is maintained for the life of the ship. This simulation may be deployed on board as described in Pt 6, Ch 2, 24.16 Hybrid electrical power system components - Energy management 24.16.7 in support of off-line consequence analysis.

24.23.4 Simulation tools are to conform to appropriate National or International Standards relevant to their use and are to have been validated in an equivalent application.

24.23.5 The dynamic simulation is to be verified against the energy flows encountered during the ship’s real performance to the extent that this is reasonably practicable.

24.23.6 Proprietary simulation tools not conforming to an appropriate National or International Standard will be subject to special consideration. This consideration will include:

1. Pedigree of the underlying modelling platform on which the simulation is built;
2. Qualitative assessment of the simulation's functional capabilities and model behaviours;
3. Configuration management of the simulation model, its architecture, functional blocks and the parameters on which it is based;
4. Prior quantitative assessment of the simulation’s performance in a similar application; and
5. An engineering justification that the validation and verification of the simulation is sufficient to enable its application in all normal and reasonably foreseeable abnormal operating and fault conditions.

24.24.1 The hybrid electrical power system is to be analysed for its electrical performance under all defined operating modes and all normal and reasonably foreseeable abnormal operating and fault conditions.

24.24.2 The analysis is to include, but not be limited to:

1. Fault levels under short circuit conditions;
2. Fault flows under short circuit and overload conditions;
3. Protection device operation, discrimination and coordination;
4. Quality of power supplies;
5. Steady state performance;
6. Transient performance;
7. Earth fault currents;
8. Resonance; and
9. Common mode and circulating currents.

24.24.3 Information regarding the expected resistance, inductance and capacitance in the system and the installed components is to be provided as part of the analysis study as required by Pt 6, Ch 2, 1.2 Documentation required for design review. The values chosen are to be based upon the component tolerances which result in the worst case for each aspect of the analysis and are to be updated with actual values when determined from component, sub-system or system test.

24.24.4 For Hybrid Power (+) notation the analysis is to be by a dynamic simulation that can be exercised under all normal, abnormal and fault conditions, that is maintained for the life of the ship and that can be exercised to verify operation of the protection system including:

1. Short circuit, single or multiple phases/poles;
2. Overload;
3. Overcurrent;
4. Current imbalance;
5. Voltage imbalance;
6. Zone protection;
7. Arc fault;
8. Earth fault;
9. Under/over voltage;
10. Under/over frequency;
11. Harmonic content;
12. Quality of power supplies including degradation detection;
13. Energy flow including any regeneration by consumers;
14. Resonance and stability;
15. Transient impact of fault detection, clearance and isolation;
16. Transient impact of sources, stores and consumers being tripped or shut down;
17. Transient impact of load changes, both increase and decrease; and
18. Load sharing imbalance.

24.24.5 Simulation tools are to conform to appropriate National or International Standards relevant to their use and are to have been validated in an equivalent application.

24.24.6 The dynamic simulation is to be verified against the ship’s real performance to the extent that this is reasonably practicable.

24.25.1 Safety functions related to the hybrid electrical power system and its constituent parts are to be clearly defined covering their purpose, their functionality and their location.

24.25.2 Safety functions are to comply with Pt 6, Ch 1, 2 Essential features for control, alarm, monitoring and safety systems .

24.25.3 Safety functions including ESD, emergency stop and reversionary control procedures for the hybrid electrical power system are to be defined, fully documented and made available to the Operators, maintainers and regulatory authorities.

24.26.1 Where the hybrid electrical power system introduces new technologies or topologies not covered by the current Rules and Regulations then a risk assessment study is to be carried out.

24.26.2 A formal method acceptable to LR is to be used to determine if new or significantly greater hazards than those normally associated with the ship electrical power system that would be mitigated by compliance with the Rules and Regulations have been introduced (e.g. a preliminary hazard analysis or a structured checklist approach (HAZID) in accordance with ISO 31010, Risk management – Risk assessment techniques).

24.26.3 Where the results of this formal method establish that new hazards or exist, the risk assessment study is to be undertaken to a recognised standard that is acceptable to LR (e.g. ISO 31010, Risk management – Risk assessment techniques) and in accordance with ShipRight Procedure Risk Based Certification (RBC).

24.26.4 The objectives of the study are to:

1. identify potential deviations from the intended operation of the hybrid electrical power system;
2. identify the causes of each deviation, and the consequences for safety and dependability;
3. list safeguards to minimise causes and consequences; and
4. determine and recommend if further safeguards should be considered.

24.26.5 The scope of the study is to consider normal operation, start-up, normal shutdown, non-use and emergency shutdown of the hybrid electrical power system.

24.26.6 The risk assessment technique(s) selected are to be appropriate for their intended use and are to be accepted by LR.

24.27.1 An overall hybrid electrical power system FMEA is to be undertaken. The objectives of the analysis are to identify:

1. potential failures;
2. consequences of failure on the hybrid electrical power system and on ship operations;
3. means to eliminate or prevent failure; and
4. means to eliminate or minimise consequences.

24.27.2 The analysis may identify the requirement for safety measures in addition to those specifically stated in these Rules. Where additional safety measures are identified, evidence is to be provided that demonstrates how they are implemented and validated.

24.27.3 As a minimum, the scope of the analysis is to consider the ‘fail safe’ condition, location and arrangement of the critical system elements.

24.27.4 The analysis is to be undertaken to a recognised standard (e.g. IEC 60812, Analysis techniques for system reliability – Procedure for failure mode and effects analysis (FMEA)), or an equivalent and acceptable National or International Standard.

24.27.5 The FMEA is to consider but not be limited to:

1. Hidden faults that are not annunciated to or evident to the Operator where a second subsequent fault can directly result in a significant failure and hazardous condition;
2. Foreseeable inadvertent operation of the hybrid electrical power system;
3. Failure to complete transition sequences (e.g. change of operating mode or response to a fault including its detection, clearance, isolation and reconfiguration);
4. Items which can be dormantly failed and unavailable to perform their intended operation on demand (e.g. normal to backup changeover systems or standby start systems);
5. Enabling systems not part of the hybrid electrical power system (e.g. fuel supply, lubrication, cooling and ventilation systems) whose failure could affect correct functioning of the hybrid electrical power system;
6. Sensor and feedback errors in programmable electronic systems;
7. Parameter corruption in programmable electronic systems (e.g. incorrect scaling factors, control rates, alarm thresholds or trip levels);
8. Common cause effects in programmable electronic systems (e.g. network storms in networked systems, power supply faults, time dependent errors in operating systems with the potential to concurrently impact multiple redundant control or monitoring systems);
9. Common cause effects in electrical power systems (e.g. power quality outside expected range or multiple earth faults in a parallel connected system);
10. Consequential failures resulting from a single failure that are to be considered as an integral part of the single failure; and
11. The viability of the role of the human in the detection and mitigation of faults.

24.27.6 Examples of devices in which hidden failures can occur that are detrimental to the dependability of a hybrid electrical power system include but are not limited to:

1. Protection devices – protection relays, dead-bus sensing;
2. Automatic isolation devices;
3. Circuit breaker open/close/trip functions;
4. Fault/current limitation devices;
5. Arc detection;
6. Load shedding devices;
7. Safety devices;
8. Fault detection systems;
9. Alternator current boost systems;
10. Interlocks and inter-trips;
11. Automatic change-over systems, transfer and dual-feed arrangements;
12. Stand-by start arrangements;
13. Transducers/sensors – giving an incorrect output;
14. Slow processors (e.g. watchdog functions);
15. UPS backed-up supplies; and
16. Active failures of control systems – working but not doing what was intended,

24.27.7 Hybrid electrical power system failure modes identified through the FMEA that could impact the safe operation and performance of any component of the system (source/store/consumer/combination/distribution system/energy management) are to be notified to, and acknowledged by, the party accountable for the safety of the component through an auditable process.

24.27.8 Component failure modes that could impact the safe operation and performance of the hybrid electrical power system are to be notified to, and acknowledged by, the hybrid electrical power system integrator through an auditable process.

24.27.9 For Hybrid Power (+) notation FMEAs for each of the key components of the system may be requested by LR in support of the system FMEA.

24.28.1 Operating Manuals are to be provided on board and submitted for information where requested by LR. The manuals are to include, but not be limited to, the following information:

1. Particulars and a description of the systems;
2. Operating instructions for the equipment and systems (including fire isolation aspects);
3. Maintenance instructions for the installed arrangements, including procedures to prevent injury from electric shock and arc flash;
4. Software configuration management procedures which are to include a list of all versions of the software installed in the system, and the settings, values of system or equipment specific configuration parameters; and
5. Output from the risk assessment processes that is necessary for the safe operation of the system under all normal and reasonably foreseeable abnormal operating conditions.

24.28.2 Overall hybrid electrical power system operating instructions are to be verified by the system designer for their completeness and correctness in all operating modes and for all foreseeable normal and abnormal operating and fault conditions. The verified instructions are to be submitted to LR.

24.28.3 Consistency between the overall system instructions and those for each component of the system is to be confirmed by the system designer.

24.28.4 All mitigating actions arising from the FMEA that require manual intervention are to be confirmed as included in the operating instructions.

24.28.5 Procedures for reversionary (e.g. manual) control of the hybrid electrical power system are to be included and are to be verified during practical operation.

24.29.1 Training needs specific to the ship and necessary for its safe operation are to be identified and documented in the ship’s operating manual.

24.29.2  For Hybrid Power (+) notation any ship-specific Operator training is to be verified by the system designer for its completeness and correctness in all operating modes and for all foreseeable normal and abnormal operating and fault conditions with evidence of verification submitted to LR.

24.30.1 The activities detailed in Pt 6, Ch 2, 24.18 Power system development and integration - General to Pt 6, Ch 2, 24.29 Power system development and integration - Operator training are to be maintained throughout the whole lifecycle of a ship and are to be verified at Periodic Survey.

24.30.2 Proposed changes to the hybrid electrical power system including its components that may impact on system safety or dependability are to be formally reviewed and accepted by the system integrator before their incorporation with details submitted to LR.

24.30.3 For Hybrid Power (+) notation details of incidents arising during any and all operations of the hybrid electrical power system that has, or could have, resulted in a hazardous consequence for people, platform or the environment are to be monitored.

24.31.1 Compliance with the requirements in Pt 6, Ch 2, 1.2 Documentation required for design review 1.2.18 is deemed to satisfy the functional requirements and performance requirements above.

24.32.1 Testing and trials in accordance with Pt 6, Ch 2, 21 Testing and trials are to be carried out as applicable.

24.32.2 Where required by the Rules and Regulations for the Classification of Ships, July 2022, items are to be constructed under survey.

24.32.3 Materials are to be approved, manufactured and tested in accordance with a standard acceptable to LR.

24.32.4 The fault ride-through capability of the system is to be demonstrated during practical tests on the system.

24.32.5 Quality of power supply testing of the system and the components is to be carried out to prove the equipment is capable of operating under the variations specified by the hybrid electrical power system integrator and accepted by LR for all normal and reasonably foreseeable abnormal operating conditions.

24.32.6 Where considered necessary by LR, additional testing may be required.

24.32.7 Satisfactory operation and load testing of the hybrid electrical power system in harbour and during sea trials are to be witnessed by LR.

24.32.8 Measurements are to be taken as part of the trials to verify that the installation will provide a quality of power supply in accordance with the values declared by the hybrid electrical power system integrator as described in Pt 6, Ch 2, 24.17 Transversal requirements.

24.32.9 For Hybrid Power (+) notation additional trials are to be carried out to:

1. Verify that the system delivers the determined levels of performance as described in Pt 6, Ch 2, 24.5 Hybrid electrical power system performance - System performance targets;
2. Verify that the system fulfils the redundancy principles defined by the hybrid electrical power system integrator as described in Pt 6, Ch 2, 24.6 Hybrid electrical power system performance - Dependability principles;
3. Verify the correct operation of the additional energy management functionality described in Pt 6, Ch 2, 24.16 Hybrid electrical power system components - Energy management;
4. Verify that the system performs in accordance with its simulation(s) as described in Pt 6, Ch 2, 24.23 Power system development and integration - Energy flows and Pt 6, Ch 2, 24.24 Power system development and integration - Power system analysis; and
5. Verify the findings of the FMEA analysis detailed in Pt 6, Ch 2, 24.27 Power system development and integration - System Failure Modes and Effects Analysis (FMEA) and the response of the system to simulated failures.