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BE1-87G Functional Description
3-1
SECTION 3
●
FUNCTIONAL DESCRIPTION
INTRODUCTION
This section describes how the BE1-87G functions and explains its operating features.
BE1-87G FUNCTION BLOCKS
BE1-87G function blocks are illustrated in Figure 3-1 and described in the following paragraphs.
Figure 3-1. Function Block Diagram
Current Sensing Inputs
Sensing current for each monitored phase is provided by two user-provided, system CTs with secondary
windings that match the BE1-87G’s sensing input range. BE1-87G relays with sensing input range 1 (style
x1x-xxx-xxxx) require CTs with 5 Aac secondary windings. Relays with sensing input range 2 (style x2x-
xxx-xxxx) require CTs with 1 Aac secondary windings. Two CTs are used on each phase—one CT on
each side of the protected machine. Sensing current is applied to internal transformers that provide
system isolation and determine the differential and sum currents. These CTs are gapped to withstand dc
offset.
Stabilizing Reactor
To minimize dissimilar performance of the system CTs, the stabilizing reactor acts as a stabilizing
impedances during external faults. Stabilizing reactors are current rated based on time and ambient
temperature (refer to Section 1,
General Information, Specifications
). Figures 3-2 and 3-3 illustrate the
stabilizing reactor impedance characteristic.
Содержание BE1-87G
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Страница 39: ...9170800990 Rev M BE1 87G Installation 4 9 Figure 4 8 Outline Dimensions Rear View Double Ended Mounting Case...
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Страница 46: ...4 16 BE1 87G Installation 9170800990 Rev M Figure 4 15 Typical DC Control Connections...
Страница 47: ...9170800990 Rev M BE1 87G Installation 4 17 Figure 4 16 Single Phase Sensing Connections...
Страница 48: ...4 18 BE1 87G Installation 9170800990 Rev M Figure 4 17 Three Phase Sensing Connections Wye Connected Generator...
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Страница 56: ...5 4 BE1 87G Testing and Setting 9170800990 Rev M Figure 5 3 Operating Characteristics Relay Style x1x xxx xxxxx...
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