GE F60 UR Series, Instruction Manual

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3-14 F60 Feeder Protection System GE Multilin
3.2 WIRING 3 HARDWARE
3
A relay configured for high impedance fault detection element includes two CT/VT modules: one type 8F, 8G, 8H, or 8J
module and one type 8Z module. For correct operation of the high impedance fault detection element, the ground current
terminals of the two CT modules must be connected to a ground current source, either a zero-sequence CT (see the
Typi-
cal wiring diagram with high impedance fault detection earlier in this chapter) or, if a zero-sequence CT is not available, to
the neutral conductor of the phase CTs (see diagram below).
Figure 3–16: TYPICAL 8Z MODULE WIRING WITH PHASE CTS
3.2.5 CONTACT INPUTS/OUTPUTS
Every digital input/output module has 24 terminal connections. They are arranged as three terminals per row, with eight
rows in total. A given row of three terminals may be used for the outputs of one relay. For example, for form-C relay outputs,
the terminals connect to the normally open (NO), normally closed (NC), and common contacts of the relay. For a form-A
output, there are options of using current or voltage detection for feature supervision, depending on the module ordered.
The terminal configuration for contact inputs is different for the two applications.
The digital inputs are grouped with a common return. The F60 has two versions of grouping: four inputs per common return
and two inputs per common return. When a digital input/output module is ordered, four inputs per common is used. The four
inputs per common allows for high-density inputs in combination with outputs, with a compromise of four inputs sharing one
common. If the inputs must be isolated per row, then two inputs per common return should be selected (4D module).
The tables and diagrams on the following pages illustrate the module types (6A, etc.) and contact arrangements that may
be ordered for the relay. Since an entire row is used for a single contact output, the name is assigned using the module slot
position and row number. However, since there are two contact inputs per row, these names are assigned by module slot
position, row number, and column position.
Some form-A / solid-state relay outputs include circuits to monitor the DC voltage across the output contact when it is open,
and the DC current through the output contact when it is closed. Each of the monitors contains a level detector whose out-
put is set to logic “On = 1” when the current in the circuit is above the threshold setting. The voltage monitor is set to “On =
1” when the current is above about 1 to 2.5 mA, and the current monitor is set to “On = 1” when the current exceeds about
80 to 100 mA. The voltage monitor is intended to check the health of the overall trip circuit, and the current monitor can be
used to seal-in the output contact until an external contact has interrupted current flow.
Block diagrams are shown below for form-A and form-A / solid-state relay outputs with optional voltage monitor, optional
current monitor, and with no monitoring
832752A3.CDR
7c 8c
8b
8a 5c
5b 5a 7b 7a
3c
4b 4a
4c 1c
2b
2a
6b 6a
6c 2c
1b 1a 3b 3a
CURRENT INPUTS NOT USED
8Z
M M M M M M M M M M M M M M M M M M M M M M M M
IA
IB IC
IG
IA5
IA1
IB5 IC5 IG5
IB1 IC1
IG1
A
B
C
POSITIVE WATTS
(5 Amp CT)
52
8F / 8G
8c 8a 7c
5a 5c 6a 7a 6c
VX
VA VB VC
VOLTAGE INPUTS
VX VA VB VC
1c
F F F F F F F F F F F F F F F F F F F F
3c 3b
CURRENT INPUTS
2c
4c 1a
4b 4a 1b
2a 3a
2b
IA IB IC IG
IA5
IA1
IB5 IC5 IG5
IB1 IC1
IG1