14.1.3 Setting guidelines
GlobalBaseSel: Selects the global base value group used by the function to define IBase,
VBase and SBase as applicable.
Current circuit supervision CCSSPVC (87) 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.
Pickup_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
Section 14 1MRK 506 369-UUS -
Secondary system supervision
624 Line distance protection REL670 2.2 ANSI
Application manual
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