Transformer Model And Identification - Siemens SINAMICS S120 System Manual

Detailed descriptions of the function modules
6.3 Supplementary functions
The administration parameters for this can be found starting at p0150[0]ff, the VSM
measured values are then available in index 0 of parameter p5460.
Voltages u12
synchronization" function is to be used. The administration parameters for this are available
from p0150[1]ff; the VSM measured values are in index 1 of parameter p5460.
6.3.2

Transformer model and identification

In addition to having a specific ratio, other significant properties of transformers include
introducing a phase shift, having a leakage inductance (results in a voltage drop) as well as
a magnetizing inductance; this is decisive for the magnetizing current and setting the DC
component control.
The precise ratio and the phase shift are of significance for the transformer magnetization
function. Both data can be taken from the transformer data sheet, and must be set as
precisely as possible in p6420[0] and p6421[0]. With p5480 = 12, a fine measurement can
be performed (display in r6440, r6441), so that, with the optimum settings, equalization
currents are minimized when closing the grid contactor (see the diagram in Chapter
Commissioning example of an infeed with dynamic grid support for a power grid (Page 86)).
Further, with p5480 = 13 – in conjunction with the grid identification p3410 = 1 – the
transformer leakage inductance can be determined (r5489). To repeat a measurement,
p5480 must first be set to 1, and then set back again to a value of 13. It is important that
p5490 is precisely set if, for example, for functions such as the grid voltage control, the
transformed VSM measured values (r5488) of the transformer primary side are not used, but
instead calculated based on the results of a model (r5498).
For the island grid synchronization function, the corresponding parameters p6420[1] and
p6421[1] must be set for a transformer between the island grid and external grid. An
automated measuring routine is not available here. It is important that the parameters define
the voltage relationships between the Active Interface Module and the external grid. This
special means that in the case that transformers are connected in series, the phase shifts
are added, and the ratios must be multiplied.
With test modes p5480 = 101, 102, operation of the power generating system can be tested
with the circuit breakers open and without a connection to the grid.
64
/u23 must be sensed using an additional VSM10 if the "Island grid
ext ext
System Manual, 04/2015, A5E03347436A
Grid infeed