How To Matching Generator Sets with UPS

With technological advancements, various industries rely on uninterrupted power supply to support their information-based operations. Power systems often adopt an architecture of "grid power + generator set + high-power UPS." However, in practice, due to various reasons, generator sets or UPS systems often fail to function properly during critical grid power failures, severely impacting the secure operation of key business operations. Here are some important reminders for users:

Data center loads include both linear and non-linear loads, with UPS systems being a typical example of non-linear loads. To ensure continuous and reliable power supply from the UPS to critical equipment during emergencies, the generator set must adapt to its non-linear characteristics.

According to the Diesel Generator Set Public Platform, when a generator set does not match the backend load, severe issues often arise in aspects such as the output power quality, detection, and control of the generator set, affecting the normal operation of equipment. If abnormalities are detected during equipment operation, it is necessary to inspect the generator set while also carefully evaluating whether it is well-matched with the Preventing UPS Generator Overload.

The matching effectiveness between a high-power UPS and a generator set is primarily determined by the following factors:

Equipment Capacity: When calculating the generator set capacity, factors such as the UPS rated power, additional power from battery charging, overall efficiency, and power factor must be considered. Additionally, the impact of inrush currents from loads such as precision air conditioning, lighting, and fire-fighting elevators during startup or operation must be accounted for.

Sudden Load Application: After a sudden load is applied to the generator set, its output voltage and frequency undergo a process of continuous adjustment and oscillatory fluctuations. The transient response capability of the generator set at this time depends on factors such as the engine type, cylinder pressure, governor characteristics, rotational inertia, generator type, excitation system characteristics, and AVR performance.

Reactive Power: Generator sets are typically designed for inductive loads with a power factor of 0.8. There are no corresponding test standards or specifications for their ability to handle capacitive loads, making them generally weak in supporting capacitive loads, especially during sudden capacitive load applications. Meanwhile, the impact of the UPS on the generator set continuously varies with the start-stop cycles of the rectifier and changes in load rate. Additionally, the architecture of the UPS system also influences this impact differently.

After comprehensively understanding the characteristics of high-power UPS systems and generator sets, ZTA POWER has provided targeted solutions to achieve reasonable matching between the two from multiple perspectives.