What is a three-phase load sharing system in paralleled generators?
1 Answer
A three-phase load sharing system in paralleled generators refers to a setup in which multiple generators are connected in parallel to supply power to a common electrical load. These generators are typically of the same rating and are synchronized to generate three-phase electrical power at the same frequency and voltage.
In such a system, the main objective is to ensure that each generator shares the load proportionally based on its capacity, thus achieving a balanced distribution of the total electrical load. This is crucial to prevent overloading of individual generators and to maintain the stability and efficiency of the overall power generation system.
To achieve load sharing among paralleled generators, various control mechanisms are used. Here's a general overview of the process:
Synchronization: Before connecting a generator to the parallel bus, it must be synchronized with the other generators. This involves adjusting the generator's frequency, voltage, and phase angle to match the existing electrical system.
Control and Monitoring: Each generator is equipped with a control system that continuously monitors its electrical output, frequency, and other parameters.
Droop Control: The most common method used for load sharing in paralleled generators is "droop control." In this approach, the speed (frequency) of each generator is slightly reduced as its load increases. As a result, the voltage output of the generator decreases with the increase in load, and this decrease in voltage serves as a signal to draw more load.
Load Sharing Setting: Each generator is assigned a specific load sharing setpoint. This setpoint represents the percentage of the total load that each generator is responsible for supplying under normal conditions. For example, if there are three generators, each might be set to supply 33.33% of the total load.
Load Sensing: Load sensing circuits continuously monitor the actual load on each generator. When the load on a generator exceeds its setpoint, the generator's control system reacts by reducing its output voltage slightly, which, in turn, causes it to supply a smaller share of the total load.
Equalizing Current: As the load on each generator changes, the difference in output current between the generators creates a circulating current among them. The equalizing current flows between the generators to ensure the load sharing remains balanced.
By employing these load sharing techniques and control mechanisms, the paralleled generators can work together effectively to supply a stable and reliable power source to the connected electrical load. Proper load sharing is essential to prevent overloading of individual generators, reduce fuel consumption, and ensure the longevity of the equipment.
In such a system, the main objective is to ensure that each generator shares the load proportionally based on its capacity, thus achieving a balanced distribution of the total electrical load. This is crucial to prevent overloading of individual generators and to maintain the stability and efficiency of the overall power generation system.
To achieve load sharing among paralleled generators, various control mechanisms are used. Here's a general overview of the process:
Synchronization: Before connecting a generator to the parallel bus, it must be synchronized with the other generators. This involves adjusting the generator's frequency, voltage, and phase angle to match the existing electrical system.
Control and Monitoring: Each generator is equipped with a control system that continuously monitors its electrical output, frequency, and other parameters.
Droop Control: The most common method used for load sharing in paralleled generators is "droop control." In this approach, the speed (frequency) of each generator is slightly reduced as its load increases. As a result, the voltage output of the generator decreases with the increase in load, and this decrease in voltage serves as a signal to draw more load.
Load Sharing Setting: Each generator is assigned a specific load sharing setpoint. This setpoint represents the percentage of the total load that each generator is responsible for supplying under normal conditions. For example, if there are three generators, each might be set to supply 33.33% of the total load.
Load Sensing: Load sensing circuits continuously monitor the actual load on each generator. When the load on a generator exceeds its setpoint, the generator's control system reacts by reducing its output voltage slightly, which, in turn, causes it to supply a smaller share of the total load.
Equalizing Current: As the load on each generator changes, the difference in output current between the generators creates a circulating current among them. The equalizing current flows between the generators to ensure the load sharing remains balanced.
By employing these load sharing techniques and control mechanisms, the paralleled generators can work together effectively to supply a stable and reliable power source to the connected electrical load. Proper load sharing is essential to prevent overloading of individual generators, reduce fuel consumption, and ensure the longevity of the equipment.