GE C70 Instruction Manual page 387

CHAPTER 5: SETTINGS
Assume that Phase Instantaneous Overcurrent 1 is used by Devices 2, 3, and 4 to block Device 1. If not blocked, Device 1
trips the bus upon detecting a fault and applying a short coordination time delay.
The following settings are applied (assume Bit 3 is used by all 3 devices to send the blocking signal and Direct Inputs 7, 8,
and 9 are used by the receiving device to monitor the three blocking signals).
UR IED 2:
: "PHASE IOC1
DIRECT OUT 3 OPERAND
UR IED 3:
: "PHASE IOC1
DIRECT OUT 3 OPERAND
UR IED 4:
: "PHASE IOC1
DIRECT OUT 3 OPERAND
UR IED 1:
: "2"
DIRECT INPUT 7 DEVICE ID
DIRECT INPUT 7 BIT NUMBER
DIRECT INPUT 7 DEFAULT STATE
: "3"
DIRECT INPUT 8 DEVICE ID
DIRECT INPUT 8 BIT NUMBER
DIRECT INPUT 8 DEFAULT STATE
: "4"
DIRECT INPUT 9 DEVICE ID
DIRECT INPUT 9 BIT NUMBER
DIRECT INPUT 9 DEFAULT STATE
Now the three blocking signals are available in UR IED 1 as
communications or a device, the scheme is inclined to block (if any default state is set to "On"), or to trip the bus on any
overcurrent condition (all default states set to "Off").
Example 3: Pilot-aided schemes
Consider a three-terminal line protection application shown in the following figure.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
Figure 5-140: Sample interlocking busbar protection scheme
UR IED 2 UR IED 3
OP"
OP"
OP"
: "3"
: select "On" for security, select "Off" for dependability
: "3"
: select "On" for security, select "Off" for dependability
: "3"
: select "On" for security, select "Off" for dependability
UR IED 1
BLOCK
UR IED 4
842712A1.CDR
,
DIRECT INPUT 7 ON DIRECT INPUT 8 ON
INPUTS/OUTPUTS
, and . Upon losing
DIRECT INPUT 9 ON
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