Current circuit supervision CCSSPVC compares the residual current from a three-
phase set of current transformer cores with the neutral point current on a separate input
taken from another set of cores on the same current transformer.
IMinOp: It must be set as a minimum to twice the residual current in the supervised CT
circuits under normal service conditions and rated primary current.
Ip>Block: It is normally set at 150% to block the function during transient conditions.
The FAIL output is connected to the blocking input of the protection function to be
blocked at faulty CT secondary circuits.
14.2 Fuse failure supervision FUFSPVC
14.2.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Fuse failure supervision FUFSPVC - -
14.2.2 Application
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.
Section 14 1MRK 502 071-UEN -
Secondary system supervision
472 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
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