Definition Of Terminology; Relative Short-Circuit Power Of The Connection Point - Siemens SINAMICS S120 Engineering Manual

1 Engineering SINAMICS S120 Booksize

Definition of terminology

PCC "Point of Common Coupling" is the point where the customer's line supply is
connected with the power grid. Typically, this is the power utility transfer point, and
can be on the medium-voltage or low-voltage side.
IPC "In-Plant Point of Coupling" is the point where the converter and/or Line
Module is connected to the customer's power supply.

Relative short-circuit power of the connection point

To avoid disturbing other loads or the Line Module, the line impedance of the
connection point must not exceed certain maximum values.
The line impedance defines the short-circuit power of the connection point and is
an important parameter for evaluating line harmonics. This means that the line
impedance can be expressed using the short-circuit power; the short-circuit power
does not represent the actual physical power when a short-circuit occurs, as it links
line voltage and short-circuit current variables, which do not occur together.
The relative short-circuit power RSC is used for evaluation.
According to EN 60146-1-1, the relative short-circuit power (RSC) is defined as the
ratio of the short-circuit power S
apparent power (fundamental apparent power) S
where it is connected to the line supply IPC (In-Plant Point of Coupling).
Fig. 1-3 S at connection point IPC and influencing quantities for RSC
k-line-IPC
PCC (Point of
Common Coupling)
if
the transfer point is on
the medium-voltage side
Medium-voltage Medium-voltage
power grid line supply
▪ Short-circuit ▪ Line voltage
▪ Specific
power
▪ Line frequency
resistance
▪ Inductance per
unit length
▪ Conductor
cross-section
▪ Conductor
length
Engineering manual S120 Booksize
Entry-ID: 109808992, V1.0,
K line_IPC
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PCC (Point of
Common Coupling)
if
the transfer point is on
the low-voltage side
Line transformer Low-voltage line
supply
▪ Relative short- ▪ Line voltage
▪ Specific
circuit voltage
▪ Rated power
resistance
▪ Inductance per
unit length
▪ Conductor
cross-section
▪ Conductor
length
04/2022
of the customer's line supply to the rated
of the converter at the point
converter
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IPC (In-Plant Point of
Matching Converter line
transformer supply
▪ Relative short- ▪ Line voltage
▪ Specific
circuit voltage
▪ Rated power
resistance
▪ Inductance per
unit length
▪ Conductor
cross-section
▪ Conductor
length
Coupling)
=
~
Converter
▪ Rated apparent
power
▪ Rated power
▪ K factor
▪ Minimum RSC
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