Range of performance:
200kVA to 2.000kVA
During grid operation (System Stand By the consumer is supplied via the choke by the grid. The necessary energy is stored in the Kinetic Module (KIN). The consumer-net frequency equals the grid frequency.
The synchronous machine holds the consumer voltage constant independent from grid conditions and takes over almost the whole reactive power load necessary for the consumer. The Choke and the alternator act as a stabilizing voltage filter and suplly the consumer with clean power. Both harmonics and asymmetrics caused by the consumer are compensated or filtered to the grid. Distortion factor < 3%. The power factor of grid input is near 1.
During Mains failure, the power switch opens and the UPS load is supplied without any interruption first by the kinetic energy of the KIN module. The diesel engine starts and the electromagnetic clutch closes and accelerates the diesel from a speed of app. 300 rpm upt to nominal speed. After having reached the nominal speed the system in diesel driven operation mode takes over the supply of the UPS load ( Frequency drop <= 1%) and the recharge of the KIN-module.
On return of the Mains voltage, the consumer are synchronized back to the grid, the clutch is opened and after a defined cooldown period the diesel engine is stopped. The cooling of the system is provided either by an Vorbaukühler or by a two-stage electric-driven fan cooler, depending on the operation condition.
To shut down the NBDK-UPS it is disconnected by means of a net-synchronized by-pass switch and let the diesel engine stop. Start up of the system in reverse order of the steps.
NBDK – schematic diagram
|1 Diesel engine
3 Electromagnetic clutch
6 Synchronous alternator
4 Kinetic module
8 Grid power switch
9 Consumer power switch
|10 Alternator guards
11 By-Pass- Power switch
12 Grid supply
13 User output of UPS
14 Harmonic distortion
15 Voltage peaks
16 Voltage cut-offs
Voltage 415 up to 11kV
||a) at change of nominal load, cos-phi = 0,8,: +10%, voltage comeback within 0,3 seconds.
b) Short circuit at the input +/- 10%. Voltage tolerance after short circuit shut down < 10% within 0,3 seconds.
c) Mains shutdown at nominal voltage +10% within 0,3 seconds
||a) at grid operation = grid frequency.
b) change grid to diesel operation at takeover of 100 % load +1%.
c) static – at diesel operation +0,5%.
When desired other tolerances are possible!
1) Diesel engine
2) Electromagnetic clutch
3) Synchronous machine
4) Kinetic Module
12) Flexible clutch