GE 345, Быстрый старт

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30 345 TRANSFORMER PROTECTION SYSTEM – QUICKSTART GUIDE
ELECTRICAL INSTALLATION CHAPTER 2: INSTALLATION
Zero sequence CT installation
The various CT connections and the exact placement of a Zero Sequence CT, for ground
fault current detection, are shown in the figure below. Twisted pair cabling on the Zero
Sequence CT is recommended.
Figure 2-18: Zero sequence core balance (CT) installation
Control power
CAUTION:
Control power supplied to the relay must match the installed power supply range. If the
applied voltage does not match, damage to the unit may occur. All grounds MUST be
connected for safe, normal operation regardless of control power supply type.
The label found on the relay specifies its order code or model number. The installed power
supply’s operating range will be one of the following:
LO: 24 to 48 V DC (Range: 20 to 60 V DC)
HI: 125 to 250 V DC/120 to 240 V AC (Range: 84 to 250 V DC/66 to 265 V AC)
CAUTION:
The relay should be connected directly to the ground bus, using the shortest practical
path. A tinned copper, braided, shielding and bonding cable should be used. As a
minimum, 96 strands of number 34 AWG should be used. Belden catalog number 8660
is suitable.
CAUTION:
Isolate power prior to servicing.
N OTE
NOTE:
An external switch, circuit breaker, or other protective device must be connected near to
the equipment.
Ground connection to neutral
must be on the source side
UNSHIELDED CABLE
LOAD
A B C N G
Ground
outside CT
Source
LOAD
SHIELDED CABLE
898733.CDR
A B C
Source
To ground;
must be on
load side
Stress cone
shields