3.10
Nonvolatile memory
The relay does not include any battery backup power. If the auxiliary power is lost,
critical information such as relay configuration and settings, events, disturbance
recordings and other critical data are saved to the relay’s nonvolatile memory. The
relay’s real-time clock keeps running via a 48-hour capacitor backup.
• Up to 1024 events are stored. The stored events are visible in HMI and Event
viewer tool in PCM600.
• Recorded data
- Fault records (up to 128)
- Maximum demands
• Circuit breaker condition monitoring
• Latched alarm and trip LEDs' statuses
• Trip circuit lockout
• Counter values
3.11
Analog measurement channels
The maximum number of physical analog measurement channels is 20. This can
be achieved with two analog input modules. The protection relay also supports up
to 16 SMV channels in four separate 9-2 streams. In addition to the local or 9-2
channels, a certain number of numerical channels is always calculated from physical
measurements. This number also depends on the connection type of the TVTR
function block.
Table 90: TVTR/TCTR connection types and numerical channels
Connection type
Function block
Physical channels
Numerical channels
ULx × 1
ULxTVTR
1
0
URES
ULxTVTR
1
0
ULx × 2 (Wye/Delta)
ULxTVTR
2
4
ULx × 2 + URES (Wye/
Delta)
ULxTVTR
3
4
ULx × 3 (Delta)
ULxTVTR
3
3
ULx × 3 (Wye)
ULxTVTR
3
4
ILx × 3
ILxTCTR
3
1
IRES
RESxTCTR
1
0
ILx × 6
CMSUM
6
4
The maximum number of measurement channels is 64. This can be calculated by
adding physical and numerical channels together.
In REX640 relays, the UTVTR functions automatically calculate missing signals if
enough information is available. If measured Uo is needed for calculations but it is
not provided, it is assumed to be zero.
shows possible voltage connections
and outcome of the UTVTR function. A three-phase current connection in the ILTCTR
function always provides a calculated Io channel.
Basic functions
1MRS759142 F
156
REX640
Technical Manual