Basler Electric BE1-47N - Manual (Page 17)

9170400990 Rev J BE1-47N Functional Description 3-1
SECTION 3 • FUNCTIONAL DESCRIPTION
Introduction
BE1-47N relay functions are illustrated in Figure 3-1 and described in the following paragraphs.
Figure 3-1. Function Block Diagram
Voltage Sensing
One of two nominal voltage levels may be specified for a system frequency of 50 hertz or 60 hertz.
Voltage sensing input options are summarized in Table 3-1.
Table 3-1. Voltage Sensing Input Options
Sensing Input Option Nominal Voltage Frequency
3 120 Vac 60 Hz
4 100 Vac 50 Hz
5 208 Vac 60 Hz
6 173 Vac 50 Hz
Three-phase system voltage is supplied to internal potential transformers (PTs). These PTs are an
integral part of the sequence filter and provide isolation, step-down scaling, and phasor summation to
eliminate the zero-sequence component of the sensed voltages.
V
C
TARGET
47N
POWER SUPPLY
STATUS D2818-12
07-30-98
V
B
V
A
PHASE
SHIFT
PICKUP
SCALING
LOW
PASS
FILTER
REFERENCE
LEVEL
NEGATIVE
SEQUENCE
VOLTAGE
COMPARATOR
AND
47N
AUX.
TIMING
TARGET
27/59
AUX.
OR
TIMING
TIMING
POWER
SUPPLY
SENSOR
59
27
UNDERVOLTAGE
COMPARATOR
UNDERVOLTAGE
PICKUP
OVERVOLTAGE
PICKUP
OVERVOLTAGE
COMPARATOR
LOW
PASS
FILTER
POWER
SUPPLY
SENSOR
POWER
TO INTERNAL
CIRCUITRY
OPERATING
POWER
V
2
SEQUENCE
FILTER