3.47
Date Code 20050919
Instruction Manual
SEL-387-0, -5, -6 Relay
Differential, Restricted Earth Fault, Thermal, and Overcurrent Elements
Thermal Element (SEL-387-6 Relay)
auxiliary contacts closed), the thermal element considers the transformer de-
energized and the ambient, top-oil, and hot-spot temperatures all have the
same value.
It is the user’s responsibility to make up an “effective external contact” from
one or more 52a or 52b contacts (from one or more breakers) indicating that
all the “source” breakers are open. If the user fails to assign a properly
configured digital input to TRDE, then the top-oil and hot-spot temperatures
will increase over the ambient temperature even when the power transformer
is de-energized.
Number of Thermal Inputs (NTHM)
Range: 0–4
The maximum number of thermal inputs is four. The number of available
thermal inputs depends on your data acquisition system and the construction
of your transformer (XTYPE).
Thermal Function (THMz) (SEL-387-6 Relays With
Firmware Versions R404 and Earlier)
Range: AMB, OIL1, OIL2, OIL3
This setting determines how the SEL-387 uses the thermal inputs it receives.
The choices are AMB (ambient temperature), OIL1 (top-oil temperature 1),
OIL2 (top-oil temperature 2), and OIL3 (top-oil temperature 3). If NTHM is
set to 0, the relay assumes that it is not receiving any temperature inputs and
will use only currents for its calculations. The COMFLG bit is cleared when
NTHM is set to 0.
Ambient Temperature Input (AMB) (SEL-387-6 Relays
With Firmware Versions R606 and Later)
Range: THM1... THM4, RTD1A...RTD12A, RTD1B ...RTD12B
This setting assigns one of the selected temperature inputs to the ambient
temperature variable in the SEL-387-6 thermal model.
Top Oil 1 Temperature Input (OIL1)
(SEL-387-6 Relays With Firmware Versions R606 and Later)
Range: THM1...THM4, RTD1A...RTD12A, RTD1B...RTD12B
This setting assigns the selected temperature input to the top oil 1 temperature
variable in the SEL-387-6 thermal model. Use this setting for single tank,
three phase transformers, or as one of three top oil inputs for single tank,
single phase transformers.
Top Oil 2 Temperature Input (OIL2)
(SEL-387-6 Relays With Firmware Versions R606 and Later)
Range: THM1...THM4, RTD1A...RTD12A, RTD1B...RTD12B
This setting assigns the selected temperature input to the top oil 2 temperature
variable in the SEL-387-6 thermal model. Use this setting for two of three top
oil inputs for single tank and single phase transformers.
NOTE:
z = 0, 1, 2, ... NTHM. There are
as many THM settings as there are
thermal inputs. Each thermal input
must be properly designated.
Summary of Contents for SEL-387-0
Page 10: ...This page intentionally left blank ...
Page 16: ...This page intentionally left blank ...
Page 56: ...This page intentionally left blank ...
Page 350: ...This page intentionally left blank ...
Page 388: ...This page intentionally left blank ...
Page 456: ...This page intentionally left blank ...
Page 494: ...This page intentionally left blank ...
Page 528: ...This page intentionally left blank ...