CYG PRS-7367 User Manual

Monitoring & Control
PRS-7367 247
The frequency difference, voltage difference and Frequency changing rate difference(dFr/dt) of
voltages from both sides of the circuit breaker are calculated in the device, they are used as input
conditions of the synchronism check. When the synchronism check function is enabled and the
voltages of both ends meet the requirements of the voltage difference, Frequency changing rate
difference(dFr/dt), and frequency difference, and the measured bus voltage and line voltage for
synchro-check should not exceed the overvoltage threshold SetSN_Sync_SynOV or lag the
undervoltage threshold SetSN_Sync_SynUV, and the measured bus frequency and line frequency
for synchro-check should not exceed the overfrequency threshold SetSN_Sync_SynOF or lag the
underfrequency threshold SetSN_Sync_SynUF, it is regarded that the synchronism check
conditions are met.
Considering the closing time of the circuit breaker, the calculation of phase angle difference should
be according to the following formulas:
dq
dA

  
2
in
2
dq dq dq
df
f T T
dt
   

      
Where:


is the phase angle difference between the line voltage and bus voltage;
dq

is the variation of phase angle within the operating time of the circuit breaker;
dq
T
is the circuit breaker operating time, that is the value of Inherent time-diff, which is the time
between activating the close command for the circuit breaker and CB reaching the closed position;
in
 
is the angle compensation for the variation of phase angle, which is the value of Inherent
angle-diff;
f
is the frequency difference between the line voltage and bus voltage at the time of activating
the close command for the circuit breaker;
The measured frequencies between the settings for the maximum and minimum frequency initiate
the evaluation of the angle change to allow operation to be sent at the right moment, including the
set value of closing time of the circuit breaker time. There is an internal phase
angle[SetSN_Sync_CLOSEANG] released to block any incorrect closing pulses. The function also
resets if the Check Sync conditions are not fulfilled within the set value of the
[SetSN_Sync_RESETIME] period. This then prevents the functions from being maintained in
operation by mistake for a long time waiting for the conditions to be fulfilled.
The logic diagram of Check Sync is shown as below:

CYG PRS-7367 Specifications

General

Brand	CYG
Model	PRS-7367
Category	Control Unit
Language	English