How does the control system of diesel generator set work

At present, with the continuous increase of enterprise business, the daily power consumption of data centers is also showing a synchronous increasing trend. Once a power outage occurs, a single diesel generator cannot meet the backup power capacity requirements of the data center. Therefore, multiple units often need to operate in parallel. So how does the control system of a diesel generator set operate?

Let's take a look together.

1, In order to ensure the stability of parallel operation of diesel generator sets, droop control is often used, which means obtaining stable frequency and voltage through P/f droop control and Q/V droop control separately. This control method controls the active and reactive power output of each unit separately, without the need for harmonious communication between units, completing equal control between units, ensuring the supply-demand balance and frequency stability of the parallel system of diesel generator sets.

2, The speed regulation (active frequency control) system is based on the rated power fN of the synchronous generator. When the active power of the downstream load increases to Pred, the output frequency of the synchronous generator droops to the new stable value of fref. The slope of segment AB is the static adjustment coefficient mp of the synchronous generator, Δ F=fref fN, Δ P=PN Red. When diesel generator sets are operated in parallel, each generator dynamically adjusts its frequency and power until all load requirements are met.

3, The voltage regulation (reactive voltage control) system is the same, and the slope of the CD segment is called the reactive voltage droop control coefficient nq of the synchronous generator, which reflects the relationship between the reactive power increment of the generator set and the terminal voltage deviation Δ U=Uref UN, Δ Q=QN Qred. It can be seen from the control block diagram of synchronous generator excitation power unit that the reference voltage is obtained through the calculation of measurement link and difference adjustment link, and then compared with the generator terminal voltage (where the voltage regulator is PI operated), so that the generator terminal voltage always tracks the voltage command quickly.