GUID-FA649B6A-B51E-47E2-8E37-EBA9CDEB2BF5-ANSI V1 EN
Figure 449: Fault in a circuit from the voltage transformer to the protection relay
A fuse failure occurs due to blown fuses, broken wires or intended substation operations.
The negative sequence component-based function can be used to detect different types of
single-phase or two-phase fuse failures. However, at least one of the three circuits from the
voltage transformers must be intact. The supporting delta-based function can also detect
a fuse failure due to three-phase interruptions.
In the negative sequence component-based part of the function, a fuse failure is detected
by comparing the calculated value of the negative sequence component voltage to the
negative sequence component current. The sequence entities are calculated from the
measured current and voltage data for all three phases. The purpose of this function is to
block voltage-dependent functions when a fuse failure is detected. Since the voltage
dependence differs between these functions, 60 has two outputs for this purpose.
6.5.6 Signals
Table 769: 60 Input signals
Name
Type Default Description
I_A SIGNAL 0 Phase A current
I_B SIGNAL 0 Phase B current
I_C SIGNAL 0 Phase C current
I
2
SIGNAL 0 Negative sequence current
V_A_AB SIGNAL 0 Phase A voltage
V_B_BC SIGNAL 0 Phase B voltage
V_C_CA SIGNAL 0 Phase C voltage
Table continues on next page
1MAC059074-MB A Section 6
Supervision functions
615 series ANSI 871
Technical Manual
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