Thytronic SME2-IS User Manual

50
50
SME2-IS - Manual - 06 - 2021
FUNCTIONAL CHARACTERISTICS
Close command advance
For asynchronous grids the nal relay must be commanded (synchronisation ok) in advance to
ensure that the breaker closes in conditions of perfect synchronisation.
Depending on the breaker closing time and the frequency difference (slip frequency) and phase shift
of the measured voltages V1 and V2, the device determines the next synchronisation time. The close
commanded is issued in advance of the synchronisation time by the advance time calculated on the
basis of the frequency difference (∆f).
The electrical advance angle required to compensate for the closing delay of the breaker is dened
by:

A
= 360 ∙ (t
CB-CLOSE
+ t
MEAS
) ∙ ∆f
where:

A
: electric angle
t
CB-CLOSE
: breaker closing time in seconds
t
MEAS
: protection relay measurement time (acquisition + measurement + final relay time) in seconds
∆f: difference between the measured values of the two grid frequencies (slip frequency) in Hz
For example, with the following values:
t
CB-CLOSE
: breaker closing time in seconds = 80 ms
t
MEAS
: protection relay measurement time (acquisition + measurement + final relay time) = 40 ms
f
1
: frequency of V1 signal = 50 Hz
f
4
: frequency of V signal = 50.2 Hz
∆f: difference between the measured values of the two grid frequencies (slip frequency) = 0.20 Hz
To ensure that the breaker closes in perfect synchronisation, the relay must send the close command
when the phase difference is = 8.6 degrees and V
2
is delayed relative to V
1
.
Calibration
To compensate for tolerances in the construction of capacitive voltage dividers, you must calibrate
the input voltage.
Use the command Calibration UL4, in the menu Set \ Commands, with no faults present, to cali-
brate the amplitudes of the voltage signals.
Calibrating the phase shift between the signal - chosen from among U
L1
, U
L2
, U
L3
- and the signal
acquired by the capacitive divider requires operator action; once the command Calibration UL4
is given, the operator must enter the phase shift (PhiV1V2), available in the menu Read \ Measure-
ments \ Synchrocheck, into the parameter Phase correction V1-V2 in the menu Set \ Calibra-
tion
[1]
Note 1 The Calibration menu is only available to Level 1 users
- 0.12
- 0.10 - 0.08 - 0.06 - 0.04 - 0.02
- 0,124 - 0,122
0120
- 0,118 - 0,116
0.120 s
close angle advance 8.6 °
f1 = 50 Hz
f2 = 50.2 Hz

Thytronic SME2-IS Specifications

General

Brand	Thytronic
Model	SME2-IS
Category	Security Sensors
Language	English