Protection Responses In An Emergency; Vdc-Max Closed-Loop Control - Siemens SINAMICS SM150 Operating Instructions Manual

Operation
8.5 Functions
8.5.3.4

Protection responses in an emergency

Figure 8-8
The overview diagram shows how central components are networked. The DRIVE-CLiQ
connection between CU320-2 and PSA is considered secure because communication on the
DRIVE-CLiQ cable and Sinamics link is monitored cyclically. With regard to contactor control
for the circuit-breaker, a two-channel bypass to the open circuits is provided for safety reasons.
This ensures that the circuit-breaker triggers for every system-internal fault. This means
system errors on the CU or the PSA trigger the circuit-breaker. A bypass to the circuit-breaker
is also provided via a fiber-optic ring if faults occur in other inverter systems.
The following time-coded signals are transmitted via the fiber-optic ring:
● Pulse inhibit
● Circuit-breaker OPEN
● Short-circuiter CLOSED
● Conduction-through of all IGCTs
8.5.3.5

Vdc-max closed-loop control

The Vdc-max controller is not usually required, because the braking energy of the active infeed
is fed back into the power system. The VDC closed-loop control can increase the ruggedness
of the drive when power outages are expected or the medium-voltage power system cannot
safely absorb the braking energy.
For this purpose, the vdc-max closed-loop control must be parameterized to an activation level
above the setpoint of the Active Line Module. If a supply system fault occurs during a braking
action, the drive does not shutdown for overvoltage. The drive continues to brake with the
largest torque possible for the supply system characteristics and the internal losses.
108
Networked structures for safe shutdown in an emergency
SINAMICS SM150 6SL3845-7NN42-2AA3 HBIS Shigang WRM NTM
Operating Instructions Rev.202003051222 3005356504