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Table 9-4
Synchrophasors of the PMU
Continuous updating (measured value of current)
with, for example, 10 values per second (reporting
rate)
Every measured value has a time stamp
Phasor values of current and voltage (amplitude and
phase angle)
The following figure shows the structure of such a Wide Area Monitoring System. The data delivered from the
PMUs on the PDC are transmitted via the Inter-Control Center Communications Protocol (ICCP) according to
DIN EN 60870-6 to the network control center.
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Figure 9-3
The phasor-measurement units each have 2 communication interfaces: an Ethernet module for synchrophasor
communication via IEEE C37.118 and another module for communication with the substation automation
technology, for example, through the IEC 61850 protocol.
The central evaluation system, e.g. SIGUARD PDP Phasor Data Processor, receives the data, files, archives them
and graphically displays them on a User Interface. In this system, a self-checking function may also be
performed, for example, on undamped power swings. The further distribution of information to other PDCs or
to a control station is done here.
To maintain the required maximum errors (TVE) required in the standard IEEE C37.118, the time tolerance
relative to the UTC time reference (UTC = Universal Time Coordinated) may be maximum 10 μs. Therefore, the
device must be directly synchronized with a GPS precise time signal for the correct function of the PMU.
Phasors
A phasor u(t) = Ue
angular frequency ω. Therefore, the voltage function u(t) = Re{u(t)} is obtained as a projection of the phasor
u(t) on the real axis.
SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017
Comparison of Synchrophasors and Conventional Measured Values
Structure of a Wide-Area Monitoring System with Phasor-Measurement Units
jωt
can be displayed as a phasor that moves counterclockwise in the complex plane at the
Measured Values, Energy Values, and Supervision of the Primary System
Measured Values from the Measuring Points
Slow updating (typically every 5 seconds)
No time stamp for the measured values
RMS values without phase angle
9.5 Phasor Measurement Unit (PMU)
1001
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