Schweitzer Engineering Laboratories SEL-351A, Руководство пользователя

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3.37
Date Code 20080213
Instruction Manual SEL-351A Relay
Overcurrent, Voltage, Synchronism Check, and Frequency Elements
Synchronism Check Elements (Not in SEL-351A-1)
Setting SYNCP
Wye-Connected Voltages
The angle setting choices (0, 30, …, 300, or 330 degrees) for setting SYNCP
are referenced to V
A
, and they indicate how many degrees V
S
constantly lags
V
A
. In any synchronism check application, voltage input
VA-N
always has to be
connected to determine system frequency on one side of the circuit breaker (to
determine the slip between V
S
and V
A
). V
A
always has to meet the “healthy
voltage” criteria (settings 25VHI and 25VLO—see Figure 3.27 ). Thus, for
situations where V
S
cannot be in phase with V
A
, V
B
, or V
C
, it is most
straightforward to have the angle setting choices (0, 30, …, 300, or 330
degrees) referenced to V
A
.
Delta-Connected Voltages
The angle setting choices (0, 30, …, 300, or 330 degrees) for setting SYNC
are referenced to V
AB
, and they indicate how many degrees V
S
constantly lags
V
AB
. In any synchronism check application, voltage input
VA-VB
always has to
be connected to determine system frequency on one side of the circuit breaker
(to determine the slip between V
S
and V
AB
). V
AB
always has to meet the
“healthy voltage” criteria (settings 25VHI and 25VLO—see Figure 3.27 ).
Thus, for situations where V
S
cannot be in phase with V
AB
, V
BC
, or V
CA
, it is
most straightforward to have the angle setting choices (0, 30, …, 300, or 330
degrees) referenced to V
AB
.
Figure 2.24 shows a relay wired with delta-connected phase PTs, and a
C-phase-to-ground connected
VS-NS
input. With ABC rotation, the correct
SYNCP setting for this example is 270 degrees, the amount that V
C
lags V
AB
.
See the Application Guide entitled Compensate for Constant Phase Angle
Difference in Synchronism Check with the SEL -351 Relay Family for more
information on setting SYNCP with an angle setting.
SYNCP synchronizing phase
or
the number of degrees that synchronism
check voltage V
S
constantly lags voltage V
A
(wye-connected voltages) or V
AB
(delta-con-
nected voltages)
VA, VB, or VC (wye-
connected voltages)
VAB, VBC, or VCA
(delta-connected volt-
ages)
0°–330°, in 30° steps
TCLOSD breaker close time for angle compensation 0.00–60.00 cycles
BSYNCH SEL
OGIC
control equation
block synchronism check setting
Relay Word bits
referenced in
Table 9.6
Table 3.13 Synchronism Check Elements Settings and Settings Ranges
(Sheet 2 of 2)
Setting Definition Range
NOTE:
On setting SYNCP = 0
Settings SYNCP = 0 and SYNCP = VA
are effectively the same (voltage V
S
is
directly synchronism checked with
voltage V
A
; V
S
does not lag V
A
). The
relay will display the setting entered
(SYNCP = VA or SYNCP = 0).
NOTE:
On setting SYNCP = 0
Settings SYNCP = 0 and SYNCP = VAB
are effectively the same (voltage V
S
is
directly synchronism checked with
voltage V
AB
; V
S
does not lag V
AB
). The
relay will display the setting entered
(SYNCP = VAB or SYNCP = 0).
Courtesy of NationalSwitchgear.com