CHAPTER 6: COMMUNICATIONS DIRECT INPUTS AND OUTPUTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 159
A coordinating timer for this bus protection scheme can be selected to cover the worst
case scenario (0.4 of a power system cycle). Upon detecting a broken ring, the coordination
time should be adaptively increased to 0.6 of a power system cycle. The complete
application requires addressing a number of issues, such as failure of both the
communications rings, failure, or out-of-service conditions of one of the IEDs. Self-
monitoring flags of the direct inputs and outputs feature is used to address these
concerns.
Direct inputs and outputs for pilot-aides schemes
Consider the three-terminal line protection application shown.
Figure 137: Three-terminal line application
A permissive pilot-aided or blocking scheme can be accomplished using a dual-ring
configuration, shown as follows.
Figure 138: Dual-channel closed loop (dual-ring) configuration
Apply the following settings to implement this application. For all IEDs, set the inter-relay
application for both channels as follows in the Settings > Communications > Inter-Relay
menu.
IED 1 to IED 3 0.4 of a power system cycle
IED 1 to IED 4 0.6 of a power system cycle
IED 2 to IED 3 0.2 of a power system cycle
IED 2 to IED 4 0.4 of a power system cycle
IED 3 to IED 4 0.6 of a power system cycle
Path Delivery time
85 ,('
3OXV
85 ,('
3OXV
85 ,('
3OXV
$&'5
$&'5
85 VHULHV
,('
3OXV
7;
5;
85 VHULHV
,('
3OXV
5;
7;
7;
5;
5;
7;
85 VHULHV
,('
3OXV
5;
7;
7;
5;
To Next Page
Loading...
