Residual Flux Calculator - Hitachi Relion 650 Series Technical Manual

1MRK 511 557-UEN Rev. A
12.20.7.2

Residual Flux Calculator

Estimation of residual fluxes (integration over fixed window)
Integration
duration
IEC21000985 V1 EN-US
Figure 147: Residual Flux Estimation Cycle
TRAFOSWT continuously keeps the latest limb voltage samples in a buffer of size PreTrigFluxCalc.
Upon activation of the OPNDETECT input the function identifies the amplitude and the first suitable
voltage peak in each phase, starting from the oldest samples in the buffer. From there, it numerically
integrates the limb voltage samples (in p.u.), for a settable duration determined by PreTrigFluxCalc +
PostTrigFluxCalc. During that time, status changes of OPNDETECT are ignored.
The resulting limb fluxes are published at the FLUX1, FLUX2, FLUX3 outputs, which can be
connected to an analog disturbance recorder. As the integration runs synchronous to the acquisition
of new samples, the FLUX1/2/3 outputs appear delayed by PreTrigFluxCalc with respect to the real-
time primary voltage and current signals.
The setting PreTrigFluxCalc defines the number of cycles to be considered for integration prior to
activation of OPNDETECT, whereas PostTrigFluxCalc defines the number of cycles to be considered
for integration post OPNDETECT activation.
The function then takes a snapshot of the estimated fluxes at the FluxSnapshot timestamp. This
setting defines the instant at which the flux values are to be averaged and sent out for further
calculation or analysis, from the point at which OPNDETECT input is detected as shown in
147.
The estimated flux values of the final power cycle (at FluxSnapshot timestamp) are provided at the
outputs RESFLUXL1, RESFLUXL2 and RESFLUXL3 (individually calculated for each phase). These
residual fluxes are stored inside the function in non-volatile memory for making them available even if
the IED reboots.
At FluxSnapshot time after OPNDETECT activation, the function activates the binary output
FLUXSNAP for a duration of PreTrigFluxCalc. When the function reaches the end of this
PostTrigFluxCalc duration, binary output INTEND is activated and remains active for PreTrigFluxCalc
duration.
Technical Manual
i
PreTrigFluxCalc
OPNDETECT
FLUXSNAP
INTEND
Activating BLOCKINT input results in a different behavior of the function. This has
been elaborated in
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OPNDETECT
Winding voltage
PostTrigFluxCalc
FluxSnapshot
Section 12.20.7.7.
Section 12
Monitoring
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In TRAFOSWT
i+n
Figure
325