ABB Remote I/O RIO600 Installation And Commissioning Manual page 148

Section 6
Commissioning
140
The operation of SEQSPVC can be described with a module diagram. All modules in
the diagram are explained in the next sections.
Negative
U
2
sequence
I
2
U_A
U_B
U_C
I_A
I_B
I_C
FF_CBCLOSED
FF_DISCONOPEN
GUID-DB3E41D9-8F30-4C44-B944-E12A2889C28C V1 EN
Figure 80: Functional module diagram
Negative phase-sequence criterion
A fuse failure based on the negative-sequence criterion is detected if the measured
negative-sequence voltage exceeds the set Neg Seq Voltage Lev value and the
measured negative-sequence current is below the set Net Seq Current Lev value. The
detected fuse failure is reported to the Decision logic module.
Voltage check
The module makes a phase-specific comparison between each voltage input and the
Seal in Voltage setting. If the input voltage is lower than the setting, the corresponding
phase is reported to the Decision logic module.
Current and voltage delta criterion
The delta function can be activated by setting the Change Rate Enable parameter to
"True". Once the function is activated, it operates in parallel with the negative
sequence-based algorithm. The current and voltage are continuously measured in all
three phases to calculate:
• Change of voltage dU/dt
• Change of current dI/dt
The calculated delta quantities are compared to the respective set values of the Current
Change Rate and Voltage Change Rate settings.
The delta current and delta voltage algorithms detect a fuse failure if there is a
sufficient negative change in each phase separately. This is performed when the
phase
criterion
Voltage
check
Decision
logic
Current
and
voltage
delta
criterion
1MRS757488 H
FUSEF_U
Installation and Commissioning Manual
RIO600