Date Code 20020129
Setting the Relay
6-3
SEL-387E Instruction Manual
A
DDITIONAL
R
ELAY
S
ETTINGS
The following explanations are for settings that are not discussed in earlier sections.
Relay (RID) and Terminal (TID) Identification
The Relay Identifier (RID) and Terminal Identifier (TID) settings are typically used to identify
the equipment protected by the relay or the circuit breaker(s) controlled by the relay. The relay
tags event reports with the Relay and Terminal Identifier strings. This allows you to distinguish
the event report as one generated for a specific breaker and substation. The RID setting is
limited to 39 characters and the TID setting to 59 characters. For our example, we have selected
RID=XFMR1 and TID=STATION A.
Potential Transformer Ratio (PTR)
The relay uses the potential transformer ratio (PTR) to convert measured secondary phase-to-
neutral voltages into primary phase-phase voltages for display in the meter report. For example,
a 230 kV phase-phase line has a primary phase-to-neutral voltage of 230 kV /
»
3= 132.8 kV.
Since the secondary phase-to-neutral voltage is 67 V the PTR = 132.8 kV / 67 V
2000.
Compensation Angle (COMPANG)
This adjusts the power metering to account for angular differences between around-the-clock CT
connections and delta or wye PT connections.
Voltage-Current Winding (VIWDG)
Use this setting to tell the relay which winding current to use when calculating power for the
meter report. The configuration for a breaker-and-a-half application has typically two sets of
current transformers, the sum of whose currents supply the power transformer. For power
calculations requiring the sum through two sets of current transformers, select the WDG12
option. With this selection, the relay vectorially adds the currents from Windings 1 and 2 and
uses the resultant for further calculations.
Three-Phase Voltage Input (TPVI)
Set TPVI=Y if you have a three-phase set of PTs or open-delta connected PTs. Set TPVI=N if
you have only one PT. With TPVI=Y, the relay uses the highest of the three voltages in the
V/Hz calculation; when TPVI=N, the relay uses the A-phase voltage. A setting of TPVI=Y
enables the phase-phase, residual (ground), negative-sequence, and positive-sequence voltage
elements; enables display of three-phase and single-phase power measurements in the meter
report; and enables three-phase under-voltage blocking (Relay Word bit 27B81) of the frequency
elements. The relay uses VAB, VBC, and VCA in place of VA, VB, and VC respectively for the
27B81 logic when the PT connections are connected open-delta and DELTA_Y=D. A setting of
TPVI=N disables and hides all voltage elements but the phase-ground elements; removes single-
phase power measurements from the meter report; and modifies the under-voltage blocking of
the frequency elements so that it only uses VA. The three-phase power calculation assumes a
balanced three-phase system when TPVI=N. The TPVI=N selection supports the V/Hz element
when only a single PT is available, connected to the A phase.
