ABB Relion 670 series, Technical Manual

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Table 119: FMPSPDIS (21) Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 12 - 1 1 Selection of one of the Global Base Value
groups
7.5.6 Operation principle
7.5.6.1 The phase selection function
SEMOD153832-4 v3
Faulty phase identification with load encroachment for mho (FMPSPDIS, 21) function can be
decomposed into six different parts:
1. A high speed delta based current phase selector
2. A high speed delta based voltage phase selector
3. A symmetrical components based phase selector
4. Fault evaluation and selection logic
5. A load encroachment logic
6. A blinder logic
The total function can be blocked by activating the input BLOCK.
Delta based current and voltages
SEMOD153832-14 v5
The delta based fault detection function uses adaptive technique and is based on patent
US4409636.
The aim of the delta based phase selector is to provide very fast and reliable phase selection for
releasing of tripping from the high speed Mho measuring element and is essential to Directional
Comparison Blocking scheme (DCB), which uses Power Line Carrier (PLC) communication system
along the protected line.
The current and voltage samples for each phase passes through a notch filter that filters out the
fundamental components. Under steady state load conditions or when no fault is present, the
output of the filter is zero or close to zero. When a fault occurs, currents and voltages change
resulting in sudden changes in the currents and voltages resulting in non-fundamental waveforms
being introduced on the line. At this point the notch filter produces significant non-zero output.
The filter output is processed by the delta function. The algorithm uses an adaptive relationship
between phases to determine if a fault has occurred, and determines the faulty phases.
The current and voltage delta based phase selector gives a real output signal if the following
criterion is fulfilled (only phase A shown):
Max(ΔVA,ΔVB,ΔVC)> DeltaVMinOp
Max(ΔIA,ΔIB,ΔIC)> DeltaIMinOp
where:
ΔVA, ΔVB and ΔVC are the voltage change between sample t and sample t-1
DeltaVMinOp and
DeltaIMinOp
are the minimum harmonic level settings for the voltage and
current filters to decide that a fault has occurred. A slow evolving
fault may not produce sufficient harmonics to detect the fault;
however, in such a case speed is no longer the issue and the
sequence components phase selector will operate.
1MRK 502 066-UUS B Section 7
Impedance protection
243
Technical manual