ABB Relion 650 Series Applications Manual page 111

1MRK 505 287-UUS B
Section 9
9.1 Fuse failure supervision SDDRFUF
9.1.1 Identification
Function description
Fuse failure supervision
9.1.2 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, located as close as possible to the voltage instrument
transformers, are one of them. 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 (SDDRFUF).
SDDRFUF 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, a high value of voltage 3V
is recommended for use in isolated or high-impedance grounded networks.
The zero sequence detection algorithm, based on the zero sequence measuring quantities, a high
value of voltage 3V
directly or low impedance grounded networks. 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.
Busbar protection REB650
Application manual
Secondary system supervision
IEC 61850
identification
SDDRFUF
without the presence of the negative-sequence current 3I
2
without the presence of the residual current 3I
0
© Copyright 2013 ABB. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
- -
, is recommended for use in
0
Section 9
Secondary system supervision
M14869-1 v2
SEMOD113803-4 v8
,
2
105