GE T35 Instruction Manual page 112

5.2 PRODUCT SETUP
Figure 5–8: INTERLOCKING BUS PROTECTION SCHEME VIA DIRECT I/OS
In the above application, the following settings should be applied:
UR IED 1:
DIRECT OUTPUT DEVICE ID:
DIRECT I/O RING CONFIGURATION:
UR IED 3:
DIRECT OUTPUT DEVICE ID:
DIRECT I/O RING CONFIGURATION:
Message delivery time is approximately 0.2 of power system cycle (at 128 kbps) times number of 'bridges' between the ori-
gin and destination. Dual-ring configuration effectively reduces the maximum 'communications distance' by a factor of two.
In this configuration the following delivery times are expected (at 128 kbps) if both rings are healthy:
IED 1 to IED 2: 0.2 of power system cycle; IED 1 to IED 3: 0.4 of power system cycle;
5
IED 1 to IED 4: 0.2 of power system cycle; IED 2 to IED 3: 0.2 of power system cycle;
IED 2 to IED 4: 0.4 of power system cycle; IED 3 to IED 4: 0.2 of power system cycle
If one ring is broken (say TX2/RX2) the delivery times are as follows:
IED 1 to IED 2: 0.2 of power system cycle; IED 1 to IED 3: 0.4 of power system cycle;
IED 1 to IED 4: 0.6 of power system cycle; IED 2 to IED 3: 0.2 of power system cycle;
IED 2 to IED 4: 0.4 of power system cycle; IED 3 to IED 4: 0.2 of power system cycle
A coordinating timer for this bus protection scheme could be selected to cover the worst case scenario (0.4 of power sys-
tem cycle). Upon detecting a broken ring, the coordination time should be adaptively increased to 0.6 of 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 relays, etc. Self-monitoring flags of the direct inputs/outputs feature would
be primarily used to address these concerns.
EXAMPLE 3: PILOT-AIDED SCHEMES
Consider the three-terminal line protection application shown below:
A permissive pilot-aided scheme could be implemented in a two-ring configuration as shown below (IEDs 1 and 2 constitute
a first ring, while IEDs 2 and 3 constitute a second ring):
5-34
TX1
UR IED 1
RX2
RX1 TX2
UR IED 2
TX1 RX2
TX2
UR IED 3
RX1
"1"
"Yes"
"3"
"Yes"
UR IED 1
Figure 5–9: THREE-TERMINAL LINE APPLICATION
T35 Transformer Management Relay
RX1
TX2
RX2 TX1
UR IED 4
TX2 RX1
RX2
TX1
842716A1.CDR
UR IED 2:
DIRECT OUTPUT DEVICE ID:
DIRECT I/O RING CONFIGURATION:
UR IED 4:
DIRECT OUTPUT DEVICE ID:
DIRECT I/O RING CONFIGURATION:
UR IED 2
UR IED 3
842713A1.CDR
5 SETTINGS
"2"
"Yes"
"4"
"Yes"
GE Multilin