ABB RELION REX640 - 4.12.4.5 Operation principle

Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
4.12.4.5 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are “On” and “Off”.
The operation of SRCPTOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
Level
detector 1
RESO_IN
BLOCK
ALARM
OPERATE
Level
detector 2
Blocking
logic
Resonance
current
calculation
I3P
I_A
I_B
I_C
t
Timer 1
t
Timer 2
Figure 639: Functional module diagram
Resonance current calculation
This module calculates the resonance current per phase set as per setting Tuning
harmonic Num . The resonance current for phase A is calculated with the equation.
I RESO A I I I I
RMS A A DC A K A
_ _
_ _ _ _
= − − −
2
1
2 2 2
(Equation 289)
I
RMS_A
RMS value of current in phase A (contains up to 11
th
harmonic)
I
DC_A
DC-component in phase A current
I_A
Fundamental component in phase A current
I
K_A
K
th
harmonic component in phase A current, K is defined by setting Tuning
harmonic Num
I_RESO_A
Calculated resonance current for phase A
The resonance current is calculated through the filter implementation. The DC and
fundamental components are removed by passing the total RMS current through
the High pass filter. The K
th
harmonic component is removed by passing the
High pass filter output through the K
th
harmonic Band stop filter. The magnitude
1MRS759142 F
Protection functions
REX640
Technical Manual
1143