Section 9 Secondary system supervision
9.1 Fuse failure supervision SDDRFUF
9.1.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Fuse failure supervision SDDRFUF - -
9.1.2 Functionality
The aim of the fuse failure supervision function (SDDRFUF) is to block voltage
measuring functions at failures in the secondary circuits between the voltage
transformer and the IED in order to avoid unwanted operations that otherwise might
occur.
The fuse failure supervision function basically has three different algorithms, negative
sequence and zero sequence based algorithms and an additional delta voltage and delta
current algorithm.
The negative sequence detection algorithm is recommended for IEDs used in isolated
or high-impedance grounded networks. It is based on the negative-sequence measuring
quantities, a high value of negative sequence voltage 3V
2
without the presence of the
negative-sequence current 3I
2
.
The zero sequence detection algorithm is recommended for IEDs used in directly or
low impedance grounded networks. It is based on the zero sequence measuring
quantities, a high value of zero sequence voltage 3V
0
without the presence of the zero
sequence current 3I
0
.
For better adaptation to system requirements, an operation mode setting has been
introduced which makes it possible to select the operating conditions for negative
sequence and zero sequence based function. The selection of different operation modes
makes it possible to choose different interaction possibilities between the negative
sequence and zero sequence based algorithm.
1MRK 505 277-UUS C Section 9
Secondary system supervision
145
Technical Manual
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