There are short-time sliding measurement mean values (3 seconds, 1 minute or 5
minutes) which can be connected to other logics in the configuration tool. Blocks,
such as limiters, timers and multipurpose analog protection, can be used and
alarms can be created when needed.
Non-sliding 10-minute measured mean values are available via communication to
substation monitoring products such as COM600S. Only the main function part
with an analog signal input must be connected in relay configuration. Data can
be collected and stored with the substation monitoring system to the historian
database.
These mean values can also be found in the LHMI menus of the protection relay and
WHMI.
The applicable power quality standards include EN 50160:2010, IEEE
519-2014, IEC 61000-4-7:2002+A1:2008 and IEC 61000-4-30:2015.
10.2.4
Analog channel configuration
VHMHAI has one analog group input which must be properly configured.
Table 1623: Analog inputs
Input
Description
U3P
Three-phase voltages for voltage harmonic measurement
function VHMHAI
See the preprocessing function blocks in this document for the possible
signal sources.
There are a few special conditions which must be noted with the configuration.
Table 1624: Special conditions
Condition
Description
U3P connected to real meas-
urements
The function requires that all three voltage channels are con-
nected.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
10.2.5
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "on" and "off". Changes will result to reset the
function internal data.
The operation of VHMHAI can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
1MRS759142 F
Power quality measurement functions
REX640
Technical Manual
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