Schweitzer Engineering Laboratories SEL-411L - Single-Terminal 87 L Test Current Injection; Current Injection for 87 LA, 87 LQ, 87 LG; Current Injection for 87 LB; Current Injection for 87 LC

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SEL Application Guide 2015-12 Date Code 20150401
SINGLE-TERMINAL 87L TEST CURRENT SOURCES
When using the single-terminal test mode, the local and remote currents are injected into different
phase current inputs of the SEL-411L being tested. The currents used are determined by the
element under test. Table 1 shows the analog substitutions to test the phase, ground, and negative-
sequence fault quantities. A pictorial representation of Table 1 is shown in Figure 5.
Table 1 Single-terminal test analog substitutions
87LA 87LB 87LC 87LQ 87LG
Local IA
IA IA IA
Local IB
IB
Local IC
IC
Remote IA
IB IB IB
Remote IB
IC
Remote IC
IA
Single-Terminal
87
LA Element Test
Single-Terminal
87LB Element Test
Single-Terminal
87LC Element Test
Single-Terminal
87LG Element Test
Single-Terminal
87LQ Element Test
Local
Current
Remote
Current
87TOUT
IA
IB
87L
A
Local
Current
Remote
Current
87TOUT
IB
IC
87L
B
Local
Current
Remote
Current
87TOUT
IC
IA
87L
C
Local
Current
Remote
Current
87TOUT
IA
IB
87L
Q
Local
Current
Remote
Current
87TOUT
IA
IB
87L
G
Figure 5 Diagrams of single-terminal test analog substitutions
87LA, 87LQ, and 87LG Testing
The local current is injected into the IA current input. The remote current is injected into the
IB current input.
87LB Testing
The local current is injected into the IB current input. The remote current is injected into the
IC current input.
87LC Testing
The local current is injected into the IC current input. The remote current is injected into the
IA current input.