4.49
Date Code 20081022 Instruction Manual SEL-787 Relay
Protection and Logic Functions
RTD-Based Protection
RTD-Based Protection
RTD Input Function
When you connect an SEL-2600 series RTD Module or order the internal
RTD card option, the SEL-787 offers several protection and monitoring
functions, settings for which are described in Ta bl e 4 .16 . See Figure 2.12 for
the RTD module fiber-optic cable connections.
NOTE: The SEL-787 can monitor as
many as 10 RTDs connected to an
internal RTD card or as many as
12 RTDs connected to an external
SEL-2600 series RTD Module.
Tab le 4 .16 shows Location, Type, and
Trip/Warn Level settings only for
RTD1; settings for RTD2–RTD12 are
similar.
RTD Location
The relay allows you to independently define the location of each monitored
RTD by using the RTD location settings.
Define the RTD location settings through use of the following suggestions:
➤ If an RTD is not connected to an input or has failed in place and
will not be replaced, set the RTD location for that input equal to
OFF.
➤ For the input connected to an RTD measuring ambient air
temperature, set the RTD location equal to AMB. Only one
ambient temperature RTD is allowed.
➤ For inputs connected to monitor temperatures of apparatus,
such as transformer oil and winding temperature, set the RTD
location equal to OTH. Use the RTD identifier setting to assign
an appropriate name to the RTD, for example set
RTD1NAM := XFRMR1 OIL.
If an RTD location setting is equal to OFF, the relay does not request that an
RTD type setting be entered for that input.
RTD Type
The four available RTD types are:
➤ 100-ohm platinum (PT100)
➤ 100-ohm nickel (NI100)
➤ 120-ohm nickel (NI120)
➤ 10-ohm copper (CU10)
Table 4.16 RTD Settings
Setting Prompt Setting Range
Setting Name :=
Facto ry Defa ul t
RTD ENABLE INT, EXT, NONE E49RTD := NONE
RTD1 LOCATION OFF, AMB, OTH RTD1LOC := OFF
RTD1 IDENTIFIER 10 characters RTDNAM :=
RTD1 TYPE PT100, NI100, NI120, CU10 RTD1TY := PT100
RTD1 TRIP LEVEL OFF, 1–250 degC TRTMP1 := OFF
RTD1 WARN LEVEL OFF, 1–250 degC ALTMP1 := OFF
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