ABB RELION RET670 Applications Manual page 138

Section 6
Wide area measurement system
132
The frequency-deviation and rate-of-change-of-frequency data are sent via
the FREQ and DFREQ fields of data frame organization of IEEE C37.118.2
message format. Depends on the selected data type, the size of each field can
be 2 (Integer) or 4 (Float) bytes per IEEE C37.118.2 message.
The data sent via the FREQ field is frequency deviation from nominal
frequency (50 Hz or 60 Hz), in mHz. It is ranged from –32.767 to +32.767
Hz. Integer data type for frequency-deviation data represents 16-bit signed
integers, range –32 767 to +32 767 32, and Float data type represents actual
frequency value in IEEE floating-point format.
The data sent via the DFREQ field is Rate Of Change Of Frequency
(ROCOF), in Hertz per second times 100. It is ranged from –327.67 to
+327.67 Hz per second. Integer data type for ROCOF data represents 16-bit
signed integers, range –32 767 to +32 767 32, and Float data type represents
actual value in IEEE floating-point format.
• SendFreqInfo: Enables/Disables sending of the frequency-deviation and Rate
Of Change Of Frequency (ROCOF) data by choosing On/Off setting.
• ReportRate: It refers to the 2-byte DATA_RATE field of the configuration
frames 1, 2 and 3 organization defined in IEEE C37.118.2 message format.
The DATA_RATE field is identifying the Rate of phasor data transmissions
by a 2-byte integer word (–32 767 to +32 767). Here the user can select the
synchrophasor data reporting rate from the PMU based on the number of
frames per second.
In general, the IED has 5 different reporting rates (10, 25, 50, 100, 200 fr/s)
on the 50 Hz system frequency, and has 8 different reporting rates (10, 12,
15, 20, 30, 60, 120, 240 fr/s) on the 60 Hz system frequency. The options are
as follows:
• 10/10 fr/s (60/50Hz)
• 12/10 fr/s (60/50Hz)
• 15/10 fr/s (60/50Hz)
• 20/25 fr/s (60/50Hz)
• 30/25 fr/s (60/50Hz)
• 60/50 fr/s (60/50Hz)
• 120/100 fr/s (60/50Hz)
• 240/200 fr/s (60/50Hz)
The first number is identifying the reporting rate in a 60Hz system, and the
second number is the reporting rate in a 50Hz system. For example, if the
selected setting is 15/10 fr/s (60/50Hz), this means that the synchrophasor
data reporting rate would be 15 frames per second if the system frequency is
60Hz. Likewise, if the system frequency is 50Hz, the selected rate is equal to
10 frames per second.
• RptTimetag: It refers to the method of time-tagging used in the IED which is
related to the phasor estimation and filtering technique. The options are
FirstSample, MiddleSample and LastSample. The time-stamp of the PMU
output represents the phasor equivalent, frequency, and ROCOF of the
1MRK 504 163-UUS A
Transformer protection RET670 2.2 ANSI
Application manual