Adjustable level detectors determine at which busbar load a generator shall start or stop. According to the starting sequence, selected with push-buttons at the front, start and stop orders are distributed to the basic units.
These orders are delayed one minute in order to prevent actions by temporary load variations. The delay will be bypassed when a fault occurs on a running set, overload is detected or a controlled load is required.
The unit also determines whether or not the number of connected sets is sufficient to cover the required load under normal conditions. In this case a signal to the units will permit a set with a non-critical fault to be disconnected and stopped. This signal will also permit a requested controlled load to be connected.
The unit provides the heavy load control function. When a controlled load is requested by an external closing contact, a simulated load will be added to the real load and this may result in the starting of a new set. When enough power is available, permission will be given to connect.
Eight loads can be controlled, programmable from 20% to 160% of a generator capacity. The connection order is given at 2 s intervals for each 1 pad. After black out a delay of 30 s will prevent the connection of these loads from interfering with the connection of essential consumers.
At the request of a controlled load a corresponding lamp at the front starts flashing until the load is ordered to be connected and then it changes to steady light. The lamp remains lit and the control output activated until the request contact is opened.
The unit also determines whether or not the number of connected sets is sufficient to cover the required load under normal conditions. In this case a signal to the units will permit a set with a non-critical fault to be disconnected and stopped. This signal will also permit a requested controlled load to be connected.
The unit provides the heavy load control function. When a controlled load is requested by an external closing contact, a simulated load will be added to the real load and this may result in the starting of a new set. When enough power is available, permission will be given to connect.
Eight loads can be controlled, programmable from 20% to 160% of a generator capacity. The connection order is given at 2 s intervals for each 1 pad. After black out a delay of 30 s will prevent the connection of these loads from interfering with the connection of essential consumers.
At the request of a controlled load a corresponding lamp at the front starts flashing until the load is ordered to be connected and then it changes to steady light. The lamp remains lit and the control output activated until the request contact is opened.
The power plant control system (PPCS) on vessels is critical for managing and optimizing the generation, distribution, and consumption of electrical power on board. The central unit within this system plays a vital role in ensuring the safe, efficient, and reliable operation of the vessel's power plant. Here's an overview of its operation:
1. Central Unit Functions
The central unit of the PPCS integrates various subsystems and performs several key functions:
- Power Generation Management: Controls the operation of generators, ensuring that power generation meets the vessel's demand.
- Load Distribution: Balances the load among generators and ensures optimal usage of power.
- Safety Monitoring: Monitors critical parameters and triggers alarms or protective actions if abnormalities are detected.
- Energy Efficiency: Optimizes power generation and consumption to enhance fuel efficiency and reduce emissions.
- Data Logging and Analysis: Collects and analyzes operational data to improve maintenance and operational strategies.
2. Components of the Central Unit
- Programmable Logic Controllers (PLCs): Automate control processes and handle inputs/outputs.
- Human-Machine Interface (HMI): Provides an interface for operators to monitor and control the power system.
- Sensors and Actuators: Measure various parameters (e.g., voltage, current, temperature) and execute control actions.
- Communication Interfaces: Enable data exchange between the central unit and other systems on the vessel.
3. Operation and Control
- Start-Up and Shutdown Procedures: The central unit manages the sequential startup and shutdown of generators and other equipment to avoid surges or interruptions.
- Load Shedding: Automatically reduces non-critical loads during high demand or generator failure to maintain system stability.
- Parallel Operation and Synchronization: Ensures generators operate in parallel and are synchronized to share loads effectively.
- Automatic Voltage Regulation (AVR): Maintains consistent voltage levels despite load changes.
- Frequency Control: Ensures the electrical frequency remains within acceptable limits, crucial for equipment operation.
4. Safety and Protection
- Overload Protection: Prevents damage to generators and other equipment by disconnecting overloaded circuits.
- Short-Circuit Protection: Detects and isolates short circuits to prevent extensive damage.
- Thermal Protection: Monitors and manages temperature to avoid overheating of generators and other components.
- Alarm and Notification Systems: Alerts crew to any faults or abnormal conditions for prompt action.
5. Maintenance and Diagnostics
- Predictive Maintenance: Uses data analysis to predict and prevent equipment failures before they occur.
- Remote Monitoring and Diagnostics: Allows shore-based teams to assist with troubleshooting and maintenance planning.
- Software Updates: Regular updates to control software to enhance performance and security.
6. Integration with Other Systems
- Navigation and Communication Systems: Coordination with navigational systems to ensure optimal power usage.
- Environmental Control Systems: Integrates with systems controlling the vessel's environmental conditions.
- Emergency Systems: Works with emergency power and lighting systems to ensure safety during outages.
7. Human Factors and Training
- Operator Training: Ensures that crew members are well-trained to operate the PPCS efficiently and respond to any issues.
- User-Friendly Interfaces: HMIs are designed to be intuitive and provide clear, actionable information.
The central unit of a power plant control system on vessels is integral to the reliable and efficient operation of the vessel's electrical power system. By managing power generation, load distribution, safety, and maintenance, it ensures that the vessel operates smoothly and safely under various conditions.
