Commissioning Supplementary Controls; Commissioning Active, Reactive And Apparent Current Limiting - Siemens SINAMICS S120 System Manual

Commissioning

7.10 Commissioning supplementary controls

Overview of important parameters
● p3473[0...3] CI: cos phi signal source current indication
● p3474[0...3] CI: cos phi signal source voltage indication
● p3475[0...1] cos phi display configuration
● p3476[0...1] cos phi display smoothing time
● r3477[0...1] CO: cos phi display actual value sign
● r3478[0...1] CO: cos phi display absolute actual value
● p3479[0...1] cos phi display current measurement dead time
Function block diagrams
● 8951 Active Infeed - cos phi display
7.10 Commissioning supplementary controls
7.10.1

Commissioning active, reactive and apparent current limiting

Preconditions
● Limits p3528 up to p3533 for active currents in the motoring (r0078 > 0) and generating
(r0078 < 0) directions are a part of the regular Active Line Module control, and are always
available.
● Adjustable parameters p3524 up to p3527 are used to limit the reactive and apparent
current.
They require that at least one of the following functional modules is activated: Grid
transformer, supplementary controls, dynamic grid support.
● Adapted current limits can be parameterized for riding through grid faults using p5509
and p5520. The "Dynamic grid support" function module is required for this purpose.
● In island grid operation with grid control, with respect to the grid, the Active Line Module
acts as voltage source; the currents as well as the cosφ are defined by the
loads/consumers in the grid.
As a consequence, it is only possible to adjust the apparent current limiting (p5478). The
"Grid control" function module is required for this purpose.
Application
Without any additional settings, the instantaneous value of the total current (apparent
current) is limited to the maximum permissible current r0209. If the vector sum of the active
and reactive current exceeds this maximum value, then initially, the reactive component of
the current setpoint is reduced to zero. This means that in the case of an overload, the active
current has priority over the reactive current.
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Grid infeed