Section 11 Secondary system supervision
11.1 Fuse failure supervision FUFSPVC
IP14556-1 v3
11.1.1 Identification
M14869-1 v4
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Fuse failure supervision FUFSPVC - -
11.1.2 Application
SEMOD113803-4 v10
Different protection functions within the protection IED, operates on the basis of the
measured voltage in the relay point. Examples are:
• impedance protection functions
• undervoltage function
• energizing check function and voltage check for the weak infeed logic
These functions can operate unintentionally if a fault occurs in the secondary circuits between
the voltage instrument transformers and the IED.
It is possible to use different measures to prevent such unwanted operations. Miniature circuit
breakers in the voltage measuring circuits should be located as close as possible to the
voltage instrument transformers, and shall be equipped with auxiliary contacts that are wired
to the IEDs. Separate fuse-failure monitoring IEDs or elements within the protection and
monitoring devices are another possibilities. These solutions are combined to get the best
possible effect in the fuse failure supervision function (FUFSPVC).
FUFSPVC function built into the IED products can operate on the basis of external binary
signals from the miniature circuit breaker or from the line disconnector. The first case
influences the operation of all voltage-dependent functions while the second one does not
affect the impedance measuring functions.
The negative sequence detection algorithm, based on the negative-sequence measuring
quantities is recommended for use in isolated or high-impedance earthed networks: a high
value of voltage 3U
2
without the presence of the negative-sequence current 3I
2
is a condition
that is related to a fuse failure event.
The zero sequence detection algorithm, based on the zero sequence measuring quantities is
recommended for use in directly or low impedance earthed networks: a high value of voltage
3U
0
without the presence of the residual current 3I
0
is a condition that is related to a fuse
failure event. In cases where the line can have a weak-infeed of zero sequence current this
function shall be avoided.
A criterion based on delta current and delta voltage measurements can be added to the fuse
failure supervision function in order to detect a three phase fuse failure. This is beneficial for
example during three phase transformer switching.
1MRK 505 370-UEN D Section 11
Secondary system supervision
Busbar protection REB670 239
Application manual
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