Ship Generator Synchronization & Load Sharing: Functions, Importance, and Operation

In ships, where multiple generators are often used to provide electrical power, synchronization and load sharing play crucial roles in ensuring the efficient and reliable operation of the generator system. Synchronization refers to the process of connecting generators in parallel with the electrical grid or with each other, while load sharing refers to the equal distribution of electrical load among the generators. This article will explore the functions, importance, and operation of synchronization and load sharing in ship generator systems.

Functions of Synchronization:

Synchronization is essential for the following reasons:

  1. Voltage and Frequency Matching: When generators are connected in parallel, synchronization ensures that the voltage and frequency outputs of each generator match the electrical grid or the reference generator. This ensures a seamless transfer of electrical power and prevents potential issues, such as voltage and frequency imbalances, which can damage equipment or disrupt the power supply.
  2. Preventing Transient Phenomena: During synchronization, transient phenomena, such as voltage dips, surges, or frequency deviations, can occur. Proper synchronization techniques help minimize these transient effects, ensuring a smooth and stable transfer of load without causing disturbances to the electrical system.
  3. Grid Stability: In cases where ship generators are synchronized with the electrical grid, synchronization helps maintain the stability of the grid. By synchronizing the generator’s voltage and frequency with the grid, the generator contributes to the overall stability and reliability of the electrical supply.

Functions of Load Sharing:

Load sharing among ship generators is vital for the following reasons:

  1. Optimal Utilization of Generators: Load sharing ensures that electrical loads are distributed evenly among the available generators. This prevents overloading of any single generator, allowing for optimal utilization of the generator capacity and maximizing fuel efficiency.
  2. Redundancy and Reliability: Load sharing provides redundancy in case of a failure or maintenance of a single generator. If one generator malfunctions, the remaining generators can compensate by taking on the additional load. This enhances the reliability of the power supply, minimizing downtime and ensuring continuous operations.
  3. Efficient Operation: By distributing the load among multiple generators, load sharing allows each generator to operate at a higher percentage of its capacity. This improves the overall efficiency of the system, reducing fuel consumption and operating costs.

Operation of Synchronization:

The synchronization process involves the following steps:

  1. Voltage Matching: Before synchronization, the voltage output of the generator to be synchronized is adjusted to match the voltage of the electrical grid or the reference generator. This is typically done using the Automatic Voltage Regulator (AVR) or other voltage control devices.
  2. Frequency Matching: The frequency of the generator is adjusted to match the grid frequency or the reference generator’s frequency. The Speed Controller, which regulates the generator’s rotational speed, is used to adjust the frequency output.
  3. Phase Synchronization: The phase angle between the generator and the grid or the reference generator is adjusted to ensure proper synchronization. This is typically done using synchronizing devices, such as synchronizing relays or synchroscopes. The phase angle is adjusted by controlling the generator’s excitation system or by adjusting the speed of the generator.
  4. Closing the Circuit Breaker: Once voltage, frequency, and phase synchronization are achieved, the circuit breaker of the generator is closed to connect it in parallel with the grid or the other synchronized generators. This allows the generator to start supplying electrical power to the system.

Operation of Load Sharing:

Load sharing among ship generators involves the following steps:

  1. Load Measurement: The electrical load on each generator is measured using load sensors or current transformers. This data is sent to the Load Sharing Controller, which calculates the load distribution for each generator.
  2. Load Sharing Calculation: The Load Sharing Controller compares the measured load with the setpoint or desired load distribution. It then calculates the necessary adjustments for each generator to achieve the desired load sharing.
  3. Load Adjustment: Based on the load sharing calculation, the Load Sharing Controller sends commands to the Speed Controllers or Fuel Control Systems of each generator. These commands adjust the speed, fuel supply, or power output of each generator to achieve the desired load distribution.
  4. Load Monitoring and Balancing: Load sensors continue to monitor the electrical load on each generator in real-time. The Load Sharing Controller makes continuous adjustments to maintain the desired load sharing, taking into account changes in the electrical load or the operating conditions.

Importance of Synchronization and Load Sharing in Ship Generators:

Synchronization and load sharing are of paramount importance in ship generator systems due to the following reasons:

  1. System Reliability: Synchronization and load sharing enhance the reliability and availability of electrical power on board ships. By synchronizing multiple generators, redundancy is achieved, ensuring continuous power supply even if one generator fails or undergoes maintenance.
  2. Optimal Generator Operation: Load sharing allows for the optimal utilization of ship generators. By distributing the electrical load evenly, each generator operates at a higher percentage of its capacity, resulting in improved efficiency and reduced fuel consumption.
  3. System Stability: Synchronization helps maintain the stability of the electrical grid or the ship’s power distribution system. Proper synchronization techniques prevent voltage and frequency imbalances, minimizing disturbances and ensuring stable and reliable power supply.
  4. Ease of Maintenance: Load sharing simplifies maintenance operations. If one generator needs to be taken offline for maintenance or repair, the load is automatically redistributed among the remaining generators, ensuring continuous power supply without interruption.


Synchronization and load sharing are essential functions in ship generator systems. Synchronization ensures voltage, frequency, and phase matching between generators and the electrical grid or reference generator, facilitating a seamless transfer of electrical power. Load sharing enables the equal distribution of electrical load among multiple generators, optimizing their utilization, improving efficiency, and enhancing system reliability. These functions are critical for the smooth and efficient operation of ship generators, ensuring a stable power supply and minimizing downtime during voyages.