ABB SYN5201 3BHS109762E01 SYNCHROTACT
Functional principle
2.1 Brief description
The SYNCHROTACT 5 digital synchronizer is used for automatic synchronizing and
paralleling of generators with lines and for the paralleling of already synchronous lines.
The device is designed for system frequencies of either 50/60 Hz or 16 2/3 Hz.
SYN 5201 is a single-channel synchronizing device whose component choice and
software design provides the highest security against incorrect paralleling.
SYN 5202 consists of two independent channels with different hardware and software.
This dual-channel property maximizes security against incorrect paralleling.
All parameters required for paralleling are stored in a parameter set. The paralleling
conditions and the characteristics of the voltage and frequency matchers are defined in
this set. With the option providing seven parameter sets, paralleling can be carried out
under different conditions or with different matcher characteristics using the same
device. Seven configurable digital inputs and outputs are available for the selection and
back indication of a parameter set.
The data which are important for commissioning and for control purposes can be
uploaded or downloaded using the PC tool SynView or, alternatively, via the keypad on
the front panel of the unit
Paralleling functions
The automatic paralleling process can basically be divided into four function blocks:
1. Measuring
2. Voltage and frequency matching
3. Monitoring of paralleling conditions
4. Paralleling command generation
In the following figure, the block circuit diagram of the basic paralleling functions of
SYNCHROTACT 5 is simplified and shows a single-channel configuration. The
individual functions are described more precisely in the following sections.

Measuring
The following measured variables are generated from the two single-phase measuring
voltages:
Voltage U1, U2
U1 is the reference voltage e.g. line
U2 is the adjustable voltage e.g. generator.
Frequency f1, f2
f1 is the reference frequency
f2 is the adjustable frequency.
Voltage difference ΔU
ΔU = IU1I – IU2I
ΔU > 0 Adjustable voltage is lower
ΔU < 0 Adjustable voltage is higher
(Every 0.5 s, an average value is formed from 56 measurements; sampling period: 9 ms)
ds/dt > 0 Adjustable frequency is reduced (e.g. generator accelerates)
ds/dt < 0 Adjustable frequency increases (e.g. generator is slowed down)
With SYN 5202, the measurement is carried out separately for each channel. It is
possible to carry out three-phase measurements in order to detect connection faults
(rotary field, polarity) and losses of phase.
Voltage measurement (SYN 5202: channel 1)
The two input voltages U1 and U2 are passed to the processor via high-impedance input
resistors, differential amplifiers, low-pass filters and A/D converters.
S00002
U2U1ADSYNCHROTACT 5
PCB: SYN 5012 PCB: SYN 5011CPU
Voltage measurement channel 2 (SYN 5202 only)
The two input voltages U1 and U2 are passed through high-impedance input resistors
and differential amplifiers. The signal for the amplitude value is formed from this by
conversion and filtering . For zero-passage detection, the signal is filtered and passed
through a comparator. The signals prepared in this way are passed to the processor via
the A/D converter.