SYNCHROTACT® 5 Operating Instructions SYN 5201 SYN 5202

voltage difference. 

Pulse length: adjustable by means of the parameter tp Umin: tp = tp Umin 

Pause interval: adjustable by means of the parameter ts U; dependent on ts U and 

±ΔUmax: 

[( ) ( )] 0

2

max max

*325,01* ≥

⎪⎭

⎪

⎬

⎫

⎪⎩

⎪

⎨

⎧

⎥

⎥

⎦

⎤

⎢

⎢

⎣

⎡ Δ−+Δ+ = −Δ−

U U

Utsts U

Voltage matcher for tap changer 

The function TAP CHANGER allows constant pulse durations and pulse intervals to be 

generated, which is necessary for matching by means of the tap changer. 

Frequency matcher with variable pulse durations 

The frequency matcher issues a command the length of which is proportional to the 

current slip. The proportionality factor df/dt can be adapted to the governor. The 

frequency matcher aims at a value midway between the nearer slip limit and zero. The 

adjusting command length tpf is: 

dtdf

s

s

tpf /

2

± max

−±

=

Between 1/3 and 2/3 of smax there is a range where no adjustment takes place. The 

adjusting pulse is discontinued as soon as the slip passes through zero. The command 

length does not fall below a settable minimum value. After an adjusting command, the 

system waits for the set pulse interval ts f so that the actual values can stabilise to the 

new setpoint. 

Frequency matcher with variable intervals 

The function INVERSE f changes the way the frequency matcher functions. The pulses 

are now always the same length, but the intervals are inversely proportional to the slip. 

Pulse length: adjustable by means of the parameter tp fmin: tp = tp fmin 

Pause interval: is calculated according to the following formula (can not be set as a 

parameter): 

[ ]s

sfff

ts 30

*1

1

21

1

≤= − =

2.2.3 Monitoring of paralleling conditions 

The monitoring of the paralleling conditions can be divided into these parallel-functioning 

blocks: 

• voltage-carrying lines 

• no-voltage lines 

Paralleling of two voltage-carrying lines 

The monitoring of the paralleling conditions enables a paralleling command (CHK 

RELEASE) if the following conditions are fulfilled simultaneously: 

• the phase-angle difference is within the tolerance band 

• the slip is within the tolerance band 

• the voltage difference is within the tolerance band 

• the voltage does not fall below minimum voltage 

• the maximum voltage is not exceeded 

• the device is in operating status (OPERATING) 

• nominal frequency deviation ≤ 5 Hz

Paralleling of no-voltage lines (dead bus) 

A special case for the monitoring is the paralleling of no-voltage lines. A paralleling 

command release is only issued if the external release signal is active and the 

measuring logic enables the release at the same time. The release by the measuring 

logic can be enabled if both voltages are within one of the permitted ranges. The dead 

bus range can be defined as permissible for one, the other or both measuring voltages 

by means of the parameters U1not, U2not and 1*2not.

The monitoring of the paralleling conditions (CHK RELEASE) releases the paralleling 

command if the following conditions are fulfilled simultaneously: 

• the releasing signal for dead bus (digital input) is issued 

• the zero voltage(s) does not exceed the set threshold U0max 

• the current voltage does not fall below the minimum voltage 

• the current voltage does not exceed the maximum voltage 

• the current zero voltage situation corresponds to a configuration permitted by means 

of U1not, U2not, 1*2not 

• the device is in Operating status (OPERATING) 

2.2.4 Command generation 

The command generation makes a distinction between asynchronous and synchronous 

sources or no-voltage lines. Two modes, one for asynchronous and one for synchronous 

sources, run in parallel, so that a source can be asynchronous or synchronous at any 

time. The paralleling command is issued in the mode in which all conditions are fulfilled 

first. 

In SYN 5202 the actuation of the paralleling relays takes place separately in both 

channels. 

Asynchronous sources 

It is called asynchronous sources, if the two lines to be paralleled (or generator and line) 

are asynchronous before the circuit breaker is closed. 

From the slip s, the acceleration ds/dt, the line frequency f1 and the set paralleling time 

t on, the command generation calculates the necessary lead angle αv by which the 

paralleling command is shifted forward in time so that the main contacts close exactly on 

phase coincidence (see following figure): 

⎥

⎦

⎤ ⎢

⎣

⎡ = + ont

ontdtds sfv *

2

*/

α *1*6,3

If the measured phase-angle difference α corresponds to the lead angle αv and if all 

paralleling conditions are fulfilled at the same time (CHK RELEASE), a command is 

generated (COMMAND). 

The command length always corresponds to the set paralleling command length tp on. If 

the latter is set to OFF or zero, the command generation is no longer in operation. The 

device then functions like a synchrocheck; as soon as the release is given by the 

monitoring (CHK RELEASE) the contacts close, when the release is dropped they open