Aux 1 Unit 14 Q3

An emergency switchboard arrangement is a crucial part of a vessel’s electrical system, designed to provide power to essential services in the event of a main power failure. It’s a self-contained electrical panel that is supplied by an emergency power source, typically an emergency generator or battery bank.  

1. Electrical Distribution System – TSPS Engineering Manual – Massachusetts Maritime Academy

2. Solas Requirement – Marine Insight Academy

Key features and requirements:

• Independent Power Source: The emergency switchboard must have a dedicated and independent power source, separate from the main electrical system. This ensures that even if the main power fails, essential services can still be powered.
• Essential Services: It supplies power only to the most critical systems and equipment required for safety and navigation, such as:
  • Emergency lighting
  • Navigation lights
  • Communication systems   1. SHIP’S EMERGENCY POWER – DieselShip dieselship.com
  • Fire pumps
  • Steering gear (in some cases)   1. 200236 Know Your Ship – Nautical Institute www.nautinst.org
  • Other essential alarms and safety systems
• Location: It is usually located above the uppermost continuous deck and easily accessible from the open deck, ensuring it remains operational even in flooding or fire scenarios.   1. Solas Requirement – Marine Insight Academy academy.marineinsight.com
• Protection Devices: It incorporates protective devices like circuit breakers and fuses to safeguard the connected circuits and equipment.   1. KR100944232B1 – Marine emergency switchmoard diagram – Google Patents patents.google.com
• Automatic Transfer Switch (ATS): An ATS automatically detects the loss of main power and switches the essential loads to the emergency power source, ensuring a seamless transition.
• Clear Labeling and Indication: The switchboard should be clearly labeled and have indicators to show the status of the emergency power source and connected loads.

Purpose:

• Safety and Survival: The emergency switchboard ensures that vital systems necessary for the safety and survival of the crew and passengers remain operational during emergencies like fire, flooding, or engine failure.
• Navigation and Communication: It maintains power to navigation lights and communication systems, allowing for safe navigation and communication with other vessels or shore stations.
• Emergency Response: It powers critical equipment like fire pumps and alarms, enabling the crew to respond effectively to emergencies.

Regulations and Standards:

• SOLAS (Safety of Life at Sea): The International Convention for the Safety of Life at Sea (SOLAS) mandates the provision of an emergency electrical power source and switchboard on most passenger and cargo ships.
• Classification Societies: Classification societies have additional rules and guidelines regarding the design, installation, and testing of emergency switchboard arrangements.

Testing and Maintenance:

• Regular Testing: The emergency switchboard and its associated systems should be regularly tested to ensure their readiness for operation in an emergency. This includes testing the auto-start function of the emergency generator and verifying the operation of the ATS.   1. SHIP’S EMERGENCY POWER – DieselShip dieselship.com
• Maintenance: Routine maintenance should be carried out to keep the switchboard and its components in good working order, including cleaning, inspection, and replacement of worn or faulty parts.

In conclusion, an emergency switchboard arrangement is a vital safety feature on marine vessels. It provides a backup power source for essential services, ensuring the crew can navigate, communicate, and respond effectively to emergencies, even in the event of a main power failure.

To draw a line diagram of a main distribution switchboard, you’ll focus on representing the major components and their electrical connections in a simplified manner. Here’s what you should include and how to approach it:

Components to Include:

• Main Busbars:
  • Represent these as thick horizontal lines, often with different colors or markings to distinguish between phases and neutral.
• Incoming Power Source:
  • Show the incoming power source (generator or shore power) with a line connecting to the main busbars.
  • You may include a symbol for the main switch or circuit breaker at this point.
• Outgoing Feeders:
  • Represent each outgoing feeder (circuit) with a line branching off the main busbars.
  • Each feeder should have its own circuit breaker or fuse symbol.
• Meters and Instruments:
  • Include symbols for essential meters like voltmeters, ammeters, and frequency meters connected to the main busbars or specific feeders.
• Protective Relays:
  • Add symbols for key protective relays like overcurrent relays, earth fault relays, and reverse power relays (if applicable for parallel operation).
• Other Components (Optional):
  • Depending on the complexity of the switchboard, you may also include symbols for:
    • Switches and controls
    • Transformers
    • Bus tie breakers (for connecting multiple switchboards)
    • Other protective devices like surge arresters

Connecting Lines and Symbols:

• Single Lines: Use single lines to represent conductors, with different colors or markings to distinguish between phases, neutral, and ground.
• Circuit Breaker Symbols: Use standard electrical symbols for circuit breakers, fuses, and other protective devices.
• Meter Symbols: Use appropriate symbols for voltmeters, ammeters, etc.
• Relay Symbols: Use symbols for relays like circles with specific markings.

Example Line Diagram (Simplified):

Key Points:

• Clarity: Keep the diagram clear and uncluttered, focusing on the main components and connections.
• Labels: Label each component and feeder clearly.
• Symbols: Use standard electrical symbols for consistency and easy understanding.
• Arrangement: Arrange the components logically, typically with the main busbars at the top and feeders branching out below.
• Simplify: Avoid excessive detail. A line diagram is meant to provide a high-level overview of the system’s structure.

Additional Tips:

• Use a Ruler: Straight lines and neatness enhance the diagram’s clarity.
• Color Coding: Use different colors for different phases or types of connections.
• Orientation: The diagram can be drawn horizontally or vertically, depending on space and preference.
• Reference: If you have a specific switchboard in mind, refer to its electrical schematics or drawings for accuracy.

Remember, the level of detail in your line diagram will depend on its purpose and the intended audience. For a basic understanding of the main distribution switchboard’s layout and major components, a simplified diagram like the one above should suffice. However, more complex diagrams might be required for detailed engineering or troubleshooting purposes.

Restoring main electrical power to the emergency switchboard after a blackout involves a carefully planned and executed procedure to ensure the safety of personnel and equipment. Here’s the general process, along with necessary precautions:  

1. An Essential Guide to Power System Restoration | by Brandon Vargas – Medium

Procedure:

1. Assess the Situation:

• Determine the cause of the blackout: Identify and address the root cause of the main power failure (e.g., generator trip, shore power loss) before attempting to restore power to the emergency switchboard.
• Check Emergency Generator: Verify that the emergency generator is running and supplying power to the emergency switchboard.

2. Prepare the Main Switchboard:

• Isolate Faulty Circuits (if applicable): If the blackout was caused by a fault on a specific circuit, isolate that circuit on the main switchboard to prevent it from tripping the breaker again when power is restored.
• Check Load Status: Assess the load connected to the emergency switchboard and ensure it’s within the capacity of the main power supply.

3. Synchronize Generators (if applicable):

• Parallel Operation: If the emergency generator is intended to operate in parallel with the main generators, it must be synchronized with the main busbar before connecting it.
• Matching Parameters: This involves matching the voltage, frequency, and phase of the emergency generator with the main busbar using a synchronizing panel or controller.

4. Close the Bus Tie Breaker:

• Caution: Ensure all necessary checks and preparations are complete before closing the bus tie breaker.
• Controlled Power Transfer: Close the bus tie breaker that connects the emergency switchboard to the main switchboard. This will transfer power from the main power source to the emergency switchboard.

5. Disconnect Emergency Generator (if applicable):

• After Load Transfer: Once the main power is successfully restored to the emergency switchboard, the emergency generator can be disconnected from the busbar and shut down, if it was operating in parallel.
• Manual or Automatic: This disconnection can be done manually or automatically through the control system.

Necessary Precautions:

• Safety First: Prioritize safety throughout the process. Ensure all personnel involved are qualified and familiar with electrical safety procedures.
• Lockout/Tagout: Implement proper lockout/tagout procedures on the main switchboard and any other relevant circuits to prevent accidental energization during the restoration process.
• Communication: Maintain clear communication between the bridge, engine control room, and electrical personnel involved in the restoration.
• Gradual Load Transfer: If possible, transfer loads gradually to avoid sudden surges that could trip breakers or overload the system.
• Monitoring: Closely monitor voltage, current, and frequency during the restoration process to ensure stability and identify any potential issues.
• Emergency Preparedness: Have contingency plans in place in case of any unforeseen problems during the restoration.

Additional Points to Consider:

• Load Shedding: If the main power supply is limited, it might be necessary to shed some non-essential loads before or during the restoration to prevent overloading the system.
• Troubleshooting: If any issues arise during the restoration, troubleshoot the problem and take corrective action before proceeding.
• Documentation: Record the details of the blackout, restoration process, and any actions taken in the vessel’s logbook for future reference and analysis.

By following these procedures and taking necessary precautions, you can safely and effectively restore main electrical power to the emergency switchboard after a blackout, ensuring the continued operation of critical systems and minimizing disruptions to the vessel’s operations.