GE D90 Plus Instruction Manual page 461

CHAPTER 8: AUTOMATION
NOTE:
Synchrocheck settings
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
V or V (source Y) V or V
1 2 2 1
Phase VTs and Phase VT
auxiliary VT
Phase VT Phase VT
Phase VT and Auxiliary VT
auxiliary VT
Auxiliary VT Auxiliary VT
The voltages V and V are automatically matched so the corresponding voltages from the
1 2
two sources are used to measure conditions. A phase-to-phase voltage is used if available
in both sources. If one or both of the sources have only an auxiliary voltage, then this
voltage is used.
For example, if an auxiliary voltage is programmed to V
automatically selects V from the other source. If the comparison is required on a specific
AG
voltage, the user can externally connect that specific voltage to auxiliary voltage terminals
and then use this auxiliary voltage to check the synchronism conditions.
If using a single CT/VT module with both phase voltages and an auxiliary voltage, ensure
that only the auxiliary voltage is programmed in one of the sources used for synchrocheck.
Exception: synchronism cannot be checked between delta-connected phase VTs and a
wye-connected auxiliary voltage.
Plus
The D90 measures frequency and volts per hertz from an input on a given source with
priorities as established by the configuration of input channels to the source. The relay
uses the phase channel of a three-phase set of voltages if programmed as part of that
source. The relay uses the auxiliary voltage channel only if that channel is programmed as
part of the source and a three-phase set is not.
Select the Settings > Automation > Control > Synchrocheck menu to open the
synchrocheck configuration window.
Figure 383: Synchrocheck configuration settings
The following settings are available for each synchrocheck element. The default values
outlined are for the synchrocheck 1 element.
(source Z) Auto-selected combination
Source Y
Phase
Phase
Phase
Auxiliary
AUTOMATION CONTROL
Auto-selected
voltage
Source Z
Phase V
AB
Phase V
AB
Auxiliary V (as set for
aux
source Z)
Auxiliary V (as set for
aux
selected sources)
, the synchrocheck element
AG
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