always be on the schedule — such as action items
required to uphold equipment warranties — other
physical maintenance items
can often be driven by what
the data tells us.
Is Data Telling the Truth?
There are a number of differ-
ent remote monitoring soft-
ware tools available in the
marketplace, but two key
common denominators when
it comes to the value added by
monitoring are data quality
and automated alarm thresh-
olds. Since small variances
in the accuracy of environ-
mental and operational data
can lead to large margins of
error on performance met-
rics, having well-calibrated
environmental sensors and
granular, reliable monitoring
devices are investments with
tremendous payoff in ensuring that the data is trustworthy.
Once confdence in the quality of the data coming through is
achieved, it’s time to decide when automatic alarms should be
triggered. The most cost-effective solar monitoring takes place
when operators can be pointed in the right direction by alarms
without having to manually comb through every data point look-
ing for issues. A balance must be struck between not getting
alarms when true causes for concern arise, and getting so many
alarms that the operator is desensitized to real problems, we
don’t want operators to suffer from a “cry wolf” syndrome.
One good example of this is an irradiance threshold for zero-power alarms. We certainly do not expect solar inverters to produce real power during nighttime hours, so we would not want
alarms telling us every time an inverter has zero real power output. However, zero real power should be very alarming in the
middle of a sunny day.
Studying the normal behavior of the inverter as DC input volt-
age rises throughout the morning and falls in the evening helps us
decide when the system should
fag zero real power as some-
thing worth human investigation.
The same logic can be applied to
alarms for any other solar power
plant behavior with the fnal
result being a system that tells us
every time a human eye is truly
needed to ensure normal opera-
tion and avoid lost production or
even worse, equipment damage.
When to Dispatch
Now that we have alarms cov-
ered, the next steps involve decid-
ing when a physical dispatch to
the system location is warranted. Generally, the plant operator, in
conjunction with the asset owner, uses the remote investigation
process to arrive at this assessment.
Best practice dictates establishing general rules for this deci-
sion-making process when frst commencing a contract, so that
system availability does not end up fully dependent on the plant
A technician performs
a combiner box.
Credit: Strata Solar