Black Start In An Island Grid; Synchronizing An Island Grid To An External Power Grid - Siemens SINAMICS S120 System Manual

5.3.2.1

Black start in an island grid

Description
The "Island grid black start" function allows an autonomous island grid to be established and
subsequently maintained with the grid droop control.
For a black start (p5580 = 2) initially, a check is made as to whether the island grid is in a no-
voltage condition. The circuit breaker between the infeed and the island grid is closed and
the infeed voltage increased until the rated voltage in the island grid is reached.
The automatic black start (p5580 = 3) can be set via the mode setting. If the island grid is
already at a certain voltage level, then an immediate switch is made into grid droop operation
(standard switching to an existing grid). Otherwise, a black start is realized.
Preconditions
The "Grid transformer" function module is required.
The Active Line Module requires a power supply in order to ramp-up the grid (e.g. from an
uninterruptible power supply); this means that the device fan and additional components can
be supplied with a 24 V DC control voltage.
Further, the actual power source to supply the DC link is required. The DC link must be
established using suitable pre-charging.
If there is a disconnector between the infeed and island grid, then a 2nd VSM10 is required
in order to measure the island grid voltage with which the infeed should be connected.
5.3.2.2

Synchronizing an island grid to an external power grid

Before connecting an island grid with an external power grid at a specific voltage using a
circuit breaker, the voltage amplitude, frequency and phase must be synchronized with that
of the external power grid. The "Island grid synchronization" function is used for this purpose.
A typical application involves connecting a micro grid with a power grid (depending on the
particular demand) or establishing a power grid from several micro grids.
Grid infeed
System Manual, 04/2015, A5E03347436A
Function modules
5.3 Description of the function modules
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