A Simple Explanation of the Generator Load Sharing Principle
The generator load sharing principle is crucial to understand when attempting to parallel generators at any facility, including data centers and power plants. This is because different manufacturers’ load sharing controls may not be compatible and overloading or underloading each unit must be avoided for successful and efficient generator paralleling. There are several different ways in which efficient generator load sharing may be accomplished, such as reactive droop compensation, cross-current compensation and using different operating modes.
Generator Load Sharing Principle Examples
Although the generator load sharing principle may seem complicated, taking a closer look at different methods of generator load sharing can help to make things more clear. For example, types of load sharing include:
- Droop Load Sharing: Reactive droop compensation “allows the engine speed or alternator voltage to decline by a predetermined percentage of the output range as the load increases” (Cummins Power Generation).
- Isochronous kW and kVAR Load Sharing: Isochronous systems make use of controls to calculate load information and determine how the percentage of the generators’ load compares to the system load. kW refers to real power sharing whereas kVAR refers to reactive power; both kW and kVAR loads are calculated by control systems in order to sufficiently share loads between generators.
- Cross Current Compensation: When paralleled generators are run without intentional voltage droop, cross current compensation occurs. Voltage regulators on each generator unit should be identical for successful load sharing.
- Using Different Operating Modes: By utilizing single board paralleling controllers it becomes much easier to successfully add generators to existing systems as well as to complete upgrades to systems. Single board paralleling controllers also make it possible to operate paralleled generators in different load level modes (some generators may be set to a base, constant mode while other designated units will float and share loads as needed).
Proper generator load sharing is essential for the success of a parallel generator system and in turn for backup power. In case of emergencies when power failure occurs, redundancy is vital to keep mission-critical functions running without fail. Be sure to review different methods of and basics of the generator load sharing principle to find the best solution for your particular power generator needs. It can also be helpful to review before purchasing generators to help understand which units will be easily compatible for a paralleling set.