ABB Relion 670 Series Applications Manual page 107

1MRK 511 401-UUS F
One of the important functions of a PMU is reporting a very accurate system frequency to the PDC
client. In the IED, each of the PMUREPORT instances is able to report an accurate frequency. Each
voltage-connected preprocessor block (SMAI block) delivers the frequency data, derived from the
analog input AC voltage values, to the respective voltage phasor channel. Every phasor channel has
a user-settable parameter (
reporting to the PDC client. It is very important to set this parameter to On for the voltage-
connected phasor channels. There is an automatic frequency source selection logic to ensure an
uninterrupted reporting of the system frequency to the PDC client. In this frequency source
selection logic, the following general rules are applied:
• Only the voltage phasor channels are used
• The phasor channel with a lower channel number is prioritized to the one with a higher
channel number
As a result, the first voltage phasor is always the one delivering the system frequency to the PDC
client and if, by any reason, this voltage gets disconnected then the next available voltage phasor
is automatically used as the frequency source and so on. If the first voltage phasor comes back,
since it has a higher priority compare to the currently selected phasor channel, after 500 ms it will
be automatically selected again as the frequency source. There is also an output available on the
component which shows if the reference frequency is good, error or reference channel unavailable.
It is possible to monitor the status of the frequency reference channel (frequency source) for the
respective PMUREPORT instance on Local HMI under Test/Function status/Communication/
Station Communication/PMU Report/PMUREPORT:1/Outputs, where the
shows the selected channel as the reference for frequency and
the reference frequency is good, or if there is an error or if the reference channel is unavailable. For
more information refer to the table PMUREPORT monitored data.
Table 16:
Name
TIMESTAT
FREQ
FREQGRAD
FREQREFCHSEL
FREQREFCHERR
FREQTRIG
DFDTTRIG
MAGHIGHTRIG
MAGLOWTRIG
6.2.3.2 Reporting filters
The PMUREPORT function block implements the reporting filters designed to avoid aliasing as the
reporting frequency is lower than the sample/calculation frequency. This means, the
Bay control REC670
Application manual
PhasorXUseFreqSrc ) to be used as a source of frequency data for
PMUREPORT Monitored data
Type Values (Range)
BOOLEAN
REAL
REAL
INTEGER
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
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Unit
1=Ready -
0=Fail
- Hz
- -
- -
0=Freq ref not -
available
1=Freq ref error
2=Freq ref
available
- -
- -
- -
- -
Wide area measurement system
FREQREFCHSEL output
FREQREFCHERR output states if
Description
Time synchronization status
Frequency
Rate of change of frequency
Frequency reference channel number
selected
Frequency reference channel error
Frequency trigger
Rate of change of frequency trigger
Magnitude high trigger
Magnitude low trigger
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Section 6
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