• To measure the power system related AC quantities (voltage, current) and to calculate
the phasor representation of these quantities.
• To synchronize the calculated phasors with the UTC by time-tagging, in order to
make synchrophasors (time is reference).
• To publish all phasor-related data by means of TCP/IP or UDP/IP, following the
standard IEEE C37.118 protocol.
The C37.118 standard imposes requirements on the devices and describes the
communication message structure and data. The PMU complies with all the standard
requirements with a specific attention to the Total Vector Error (TVE) requirement. The
TVE is calculated using the following equation:
2
2
2 2
r r i i
r i
( X ( n ) X ) ( X ( n ) X )
TVE
X X
- + -
=
+
GUID-80D9B1EA-A770-4F50-9530-61644B4DEBBE V1 EN (Equation 14)
where,
X
r
(n) and X
i
(n) are the measured values
X
r
and X
i
are the theoretical values
In order to comply with TVE requirements, special calibration is done in the factory on the
analog input channels of the PMU, resulting in increased accuracy of the measurements.
The IEEE C37.118 standard also imposes a variety of steady state and dynamic
requirements which are fulfilled in the IED with the help of high accuracy measurements
and advanced filtering techniques.
Figure
38 shows an overview of the PMU functionality and operation. In this figure, only
one instance of PMUREPORT (PMUREPORT1) is shown. Note that connection of
different signals to the PMUREPORT, in this figure, is only an example and the actual
connections and reported signals on the IEEEC37.118/1344 can be defined by the user.
1MRK 506 369-UUS - Section 6
Wide area measurement system
Line distance protection REL670 2.2 ANSI 117
Application manual
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