ABB RELION REX640 Technical Manual page 1441

1MRS759142 C
REX640
Technical Manual
∆φ
Diff angle
U
BusA
U
BusB
Dead bus voltage
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Figure 768: Conditions to be fulfilled when detecting synchronism between
systems
When the measured difference of voltages (U_DIFF_MEAS) and measured
difference in frequency (FR_DIFF_MEAS) are within the synchro check limits given
in Table 1370, the output MATCH_OK is activated. The output MATCH_INPRO is
activated when the voltage and frequency matching is in progress. The matching
status input is received via ASC1_NS_DAT signal from ASCGAPC.
When the frequency, phase angle and voltage conditions are fulfilled, the duration of
the synchronism conditions is checked to ensure that they are still met when the
condition is determined on the basis of the measured frequency and phase difference.
Depending on the CB and the closing system, the delay between the closing signal and
the CB closing is about 50...250 ms. The selected Closing time of CB informs the
function how long the conditions have to persist. The value covers both the CB closing
delay and the output type dependent delay. The synchro check function compensates
for the measured slip frequency and the CB closing delay.
The closing angle advance is calculated continuously:
Closing angle = ∠ U
(
BusA
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∠U Measured bus A voltage phase angle
BusA
∠U Measured bus B voltage phase angle
BusB
Closing time of CB to be set as in
TCB Parameter
TCB t T x
CB PL
= + +
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t CB closing delay in ms
CB
T Output type dependent delay in ms (see
PL
x Hardware delays between the protection relay and CB in ms; delays due to, for example, auxiliary
relays and contactors, if used
∠
- ∠U
U
=
BusA BusB
Diff angle
Diff voltage
U U
Δ U = | | – | |
BusA BusB
Live bus voltage
Diff frequency

U f f
) (
− ∠ ° + −
BusB BusA BusB


Equation 335
Table 1371)
Section 9
Control functions
∆ f f f
= -
BusA BusB
f
f
BusB
BusA
Frequency[Hz]
Rated frequency
TCB

 
360
)
⋅ ⋅ °
 1000   
 

(Equation 334)
(Equation 335)
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