ABB RES670 Applications Manual page 96

Section 6
Wide area measurement system
90
• 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
- +
( X ( n ) X ) ( X ( n ) X )
r r
=
TVE
2
+
X X
r
GUID-80D9B1EA-A770-4F50-9530-61644B4DEBBE V1 EN-US
where,
X (n) and X (n) are the measured values
r i
X and X are the theoretical values
r i
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 35 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.
2
-
i i
2
i
1MRK 511 407-UEN C
Phasor measurement unit RES670 2.2 IEC
Application manual
(Equation 11)