8.3.5 Application
84T provides tap position information for other functions as a signed integer value that can
be fed to the tap position input.
The position information of the tap changer can be coded in various methods for many
applications, for example, the differential protection algorithms. In this function, the
binary inputs in the transformer terminal connector are used as inputs to the function. The
coding method can be chosen by setting the mode parameter. The available coding
methods are BCD, Gray and Natural binary coding. Since the number of binary inputs are
limited to seven, the coding functions are limited to seven bits including the sign bit and
thus the six bits are used in the coding functions. The position limits for the tap positions
at BCD, Gray and Natural binary coding are ±39, ±63 and ±63 respectively.
In this example, the transformer tap changer position indication is wired as a mA signal
from the corresponding measuring transducer. The position indication is connected to
input 1 (AI_VAL1) of the X130 (RTD) card. The tap changer operating range from the
minimum to maximum turns of the tap and a corresponding mA signal for the tap position
are set in X130(RTD). Since the values of the X130(RTD) outputs are floating point
numbers, the float to integer (T_F32_INT8) conversion is needed before the tap position
information can be fed to 84T. When there is a wired connection to the TAP_POS
connector, the validated tap changer position is presented in the TAP_POS output that is
connected to other functions. When there is no wired connection to the TAP_POS
connector, the binary inputs are expected to be used for the tap changer position
information.
8.3.6 Signals
Table 856: 84T Input signals
Name
Type Default Description
BI0 BOOLEAN 0=False Binary input 1
BI1 BOOLEAN 0=False Binary input 2
BI2 BOOLEAN 0=False Binary input 3
BI3 BOOLEAN 0=False Binary input 4
BI4 BOOLEAN 0=False Binary input 5
BI5 BOOLEAN 0=False Binary input 6
SIGN_BIT BOOLEAN 0=False Binary input sign bit
END_POS_R BOOLEAN 0=False End position raise or highest allowed tap position
reached
END_POS_L BOOLEAN 0=False End position lower or lowest allowed tap position
reached
TAP_POS INT8 0 Tap position indication
Section 8 1MAC059074-MB A
Measurement functions
954 615 series ANSI
Technical Manual
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