Views: 144 Author: Site Editor Publish Time: 2020-12-01 Origin: Site
At present, with the continuous growth of enterprise business, the daily energy consumption of the data center is also showing a synchronous growth trend. Once the mains power failure occurs, a single diesel generator can not meet the data center backup power supply capacity demand, so it often needs more units running in parallel. In order to improve the economics and system reliability of the power system, it requires that not only the unit itself should have good performance, but also each unit reasonably bears the active and reactive loads in the downstream system. These requirements are reflected collectively in the speed regulation system of the prime mover and the voltage regulation system of the KP206 6 cylinder turbocharger diesel engine.
In order to ensure the stability of the parallel operation of diesel generator sets, droop control is often used, P/f droop control and Q/V droop control are used to obtain stable frequency and voltage. This control method controls the active power and reactive power output by each unit separately, without the need for communication and coordination between the units, to achieve peer-to-peer control between the units, ensuring the supply and demand balance and frequency stability of the parallel system of 6 cylinder high speed turbocharger diesel engine.
The droop control adopts voltage and current dual-loop control. The inner loop dynamic response speed of the current is fast, which is used to improve the power quality of the generator set. The outer loop controller dynamic response speed of the voltage is slow, which can control the output voltage of the system and generate the inner loop reference signal. First, use the measurement module to collect the voltage and current at the load point, calculate the output instantaneous active and reactive power of new stationary 227kw turbocharger diesel engine, and then obtain the corresponding average power through the low-pass filter LPF. Assuming that the active power output by the generator set is running at rated frequency P, F, and U, which are respectively the frequency and rated voltage amplitude of the power system, and the output frequency and voltage amplitude command are obtained through the droop link, and then the reference voltage is generated through the voltage synthesis link, and then The reference voltage will be used as the input of the voltage and current dual link controller.
Taking the rated power fN of the synchronous generator as the reference value, 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, and the slope of the AB segment is the static adjustment coefficient mp of the 660kw high speed turbocharger diesel engine, Δf=fref-fN, ΔP=PN-Pred. When the diesel generator sets are operated in parallel, each generator dynamically adjusts its frequency and power until all load requirements are met. If the capacity of each generator set is the same, the static adjustment coefficient is also the same, and the output power is naturally the same. If the unit capacity is different, the static adjustment coefficient of the unit with a larger single unit capacity is larger, and the downstream load borne by the unit is naturally more.
Similarly, the slope of the CD segment is called the reactive-voltage droop control coefficient nq of the 1800rpm 4 stroke turbocharger diesel engine, which reflects the relationship between the reactive power increment of the generator set and the terminal voltage deviation, and ΔU=Uref-UN, ΔQ=QN-Qred . According to the control block diagram of the excitation power unit of the synchronous generator, the reference voltage is obtained through the calculation of the measurement link and the adjustment link, and then compared with the generator terminal voltage (where the voltage regulator is PI controlled), so that the generator terminal voltage always follow the voltage command quickly.
