3.44
SEL-387-0, -5, -6 Relay
Instruction Manual
Date Code 20050919
Differential, Restricted Earth Fault, Thermal, and Overcurrent Elements
Thermal Element (SEL-387-6 Relay)
Setting Descriptions
Thermal Element Enable (ETHER)
Range: Y, N
This setting enables or disables the thermal element. Set ETHER = Y to
enable the thermal element or ETHER = N to disable the thermal element. If
ETHER = N, the relay hides the following settings and they are unavailable to
the user.
Thermal Model Winding Current (TMWDG)
Range: 1, 2, 3, 4, 12, 34
The TMWDG setting determines which power transformer winding
corresponds with the measured currents the thermal element uses for
calculations.
The measured currents the thermal element uses must represent the total
current in or out of the power transformer. TMWDG allows selection of
Winding 1, Winding 2, Winding 3, Winding 4, Windings 1 and 2 (two currents
added together), or Windings 3 and 4 to be the current for the thermal element
calculations. Refer to the two configuration settings, E87W and EOC, to
determine which of the four windings are in use.
For a two-winding power transformer, current transformers located on either
the high-voltage or low-voltage side would provide the correct current values.
You can apply the thermal element on a three- or four-winding power
transformer, provided that the TMWDG setting represents the total current in
or out.
Winding LL Voltage (VWDG)
Range: 1–1000 kV, in 0.01 kV steps
Set VWDG to the rated phase-to-phase voltage for the winding you select in
the TMWDG setting. The relay uses VWDG in conjunction with the power
transformer MVA rating (see MCS setting) to calculate rated current. The
relay then divides measured current by the rated current to determine K,
which the relay uses in thermal element calculations.
Transformer Construction (XTYPE)
Range: 1, 3
A three-phase transformer can consist of one three-phase core and coil
assembly in one physical enclosure or three physically separate single-phase
transformers connected externally. Set XTYPE to either 3 (three-phase core
and coil assembly in one physical enclosure) or 1 (three physically separate
single-phase transformers connected externally).
TLOL = total accumulated loss of life, TLOL
RLOL = most recent daily rate of loss-of-life calculation
Содержание SEL-387-0
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