61850-7-3, Ed 2 © IEC:20xx(E) – 13 – 57/953/CDV
EXAMPLE A measured value may exceed a predefined range, however the selected data type can still represent
the value, for example the data type is a 16-bit unsigned integer, the predefined range is 0 to 40 000, if the value is
between 40001 and 65535 it is considered to be out of range.
badReference: this identifier shall indicate that the value may not be a correct value due to a
reference being out of calibration. The server shall decide if validity shall be set to invalid or
questionable (used for measurand information and binary counter information only).
oscillatory: to prevent overloading of event driven communication channels, it is desirable to
detect and suppress oscillating (fast changing) binary inputs. If a signal changes in a defined
time (t
osc
) twice in the same direction (from 0 to 1 or from 1 to 0) then it shall be defined as an
oscillation and the detail quality identifier “oscillatory” shall be set. If a configured numbers of
transient changes is detected, they shall be suppressed. In this time, the validity status
"questionable” shall be set. If the signal is still in the oscillating state after the defined number
of changes, the value shall be left in the state it was in when the oscillatory flag was set. In
this case, the validity status "questionable” shall be reset and “invalid” shall be set as long as
the signal is oscillating. If the configuration is such that all transient changes should be
suppressed, the validity status “invalid” shall be set immediately in addition to the detail
quality identifier “oscillatory” (used for status information only).
failure: this identifier shall indicate that a supervision function has detected an internal or
external failure.
oldData: a value shall be oldData if an update is not made during a specific time interval. The
value may be an old value that may have changed in the meantime. This specific time interval
may be defined by an allowed-age attribute.
NOTE "Fail silent" errors, where the equipment stops sending data will cause a oldData condition. In this case,
the last received information was correct.
inconsistent: this identifier shall indicate that an evaluation function has detected an
inconsistency.
inaccurate: this identifier shall indicate that the value does not meet the stated accuracy of
the source.
EXAMPLE The measured value of power factor may be noisy (inaccurate) when the current is very small.
6.2.4 Source
Source shall give information related to the origin of a value. The value may be acquired from
the process or be a substituted value.
process: the value is provided by an input function from the process I/O or is calculated from
some application function.
substituted: the value is provided by input of an operator or by an automatic source.
NOTE 1 Substitution may be done locally or via the communication services. In the second case, specific
attributes with a FC SV are used.
NOTE 2 There are various means to clear a substitution. As an example, a substitution that was done following an
invalid condition may be cleared automatically if the invalid condition is cleared. However, this is a local issue and
therefore not in the scope of this standard.
6.2.5 Test
Test shall be an additional identifier that may be used to classify a value being a test value
and not to be used for operational purposes. The processing of the test quality in the client
shall be a local issue. The bit shall be completely independent from the other bits within the
quality descriptor.
The test identifier should normally be propagated through all hierarchical levels.