14. Fuse failure
supervision
The fuse failure supervision detects failures
between the voltage measurement circuit and
the IED. The failures are detected by the
negative-sequence based algorithm or by the
delta voltage and delta current algorithm.
Upon the detection of a failure the fuse
failure supervision function activates an alarm
and blocks voltage-dependent protection
functions from unintended operation.
15. Current circuit
supervision
Current circuit supervision is used for
detecting faults in the current transformer
secondary circuits. On detecting of a fault the
current circuit supervision function can also
activate an alarm LED and block certain
protection functions to avoid unintended
operation. The current circuit supervision
function calculates the sum of the phase
currents and compares the sum with the
measured single reference current from a
core balance current transformer or from
another set of phase current transformers.
16. Access control
To protect the IED from unauthorized access
and to maintain information integrity, the IED
is provided with an authentication system
including user management. Using the IED
User Management tool in the Protection and
Control IED Manager PCM600, an individual
password is assigned to each user by the
administrator. Further, the user name is
associated to one or more of the four
available user groups: System Operator,
Protection Engineer, Design Engineer and
User Administrator. The user group
association for each individual user enables
the use of the IED according to the profile of
the user group.
17. Inputs and outputs
Depending on the hardware configuration
selected, the IED is equipped with six phase-
current inputs (three inputs for the HV side
and three inputs for the LV side) and one or
two neutral-current inputs for earth-fault
protection.
Depending on the selected hardware
configuration the IED includes two or three
voltage inputs. One of the voltage inputs can
be used as a residual voltage input for
directional earth-fault protection or residual
voltage protection. The voltage inputs can
also be used as phase-voltage inputs for
overvoltage, undervoltage and directional
overcurrent protection and other voltage
based protection functions.
The phase-current inputs are rated 1/5 A.
Depending on the selected hardware
configuration the IED is equipped with one
or two alternative residual-current inputs, that
is 1/5 A or 0.1/0.5 A. The 0.1/0.5 A input is
normally used in applications requiring
sensitive earth-fault protection and featuring
a core-balance current transformer.
The voltage inputs, for either phase-to-phase
voltages or phase-to-earth voltages, and the
residual-voltage input cover the rated
voltages 100 V, 110 V, 115 V and 120 V. The
rated values of the current and voltage inputs
are selected in the IED software.
In addition, the binary input thresholds are
selected by adjusting the IED’s parameter
settings. The threshold voltage can be set
separately for each binary input.
There is also an optional RTD/mA module
with 8 RTD/mA inputs and 4 mA outputs.
The optional RTD/mA module facilitates the
measurement of up to eight analog signals
Transformer Protection and Control 1MRS756978 D
RET630
Product version: 1.1 Issued: 2011-05-18
14 ABB
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