Operation Principle - ABB REC670 Applications Manual

Section 6
Wide area measurement system
6.2.3
106
IEC140000121 V2 EN-US
Figure 36: Multiple instances of BINARYREPORT blocks

Operation principle

The Phasor Measurement Unit (PMU) features three main functional principles:
• 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.
2
-
i i
2
i
1MRK 511 401-UEN A
IEC140000121-2-en.vsd
GUID-EB2B9096-2F9D-4264-B2D2-8D9DC65697E8 v3
(Equation 11)
Bay control REC670 2.2 IEC
Application manual