Hitachi Relion 670 Series Applications Manual page 318

Section 15
Monitoring
Function description
Current sequence component
measurement
Voltage sequence component
measurement
Phase-neutral voltage measurement
15.1.3 Application
Measurement functions are used for power system measurement and supervision, for reporting to
the local HMI, the monitoring tool within PCM600 or to station level for example, via IEC 61850. The
measurement functions operates properly for 16.7Hz, 50Hz and 60Hz railway power supply systems.
The possibility to continuously monitor measured values of active power, reactive power, currents,
voltages, frequency, power factor etc. is vital for efficient production, transmission and distribution of
electrical energy. It provides to the system operator fast and easy overview of the present status of
the power system. Additionally, it can be used during testing and commissioning of protection and
control IEDs in order to verify proper operation and connection of instrument transformers (CTs and
VTs). During normal service by periodic comparison of the measured value from the IED with other
independent meters the proper operation of the IED analog measurement chain can be verified.
Finally, it can be used to verify proper direction orientation for distance or directional overcurrent
protection function.
All measured values can be supervised with four settable limits:
• low-low limit
• low limit
• high limit
• high-high limit
A zero clamping reduction is also supported, that is, the measured value below a settable limit is
forced to zero which reduces the impact of noise in the inputs.
Dead-band supervision can be used to report the measured signal value to the station level when a
change in the measured value is above the set threshold limit or time integral of all changes since the
last time value updating exceeds the threshold limit. The measure value can also be based on
periodic reporting.
All measurement functions use fundamental frequency phasors (that is, DFT filtering) for internal
calculations and for reporting of measured values. However, from the following three measurement
functions CMMXU, VMMXU and VNMMXU it is also possible to report the total measured quantity
(that is, true RMS filtering). By selecting the RMS mode, the reported value will in addition to the
fundamental magnitude also include harmonics. The RMS measurement is often required for railway
power systems which are typically polluted by harmonics.
The measurement function CVMMXN is located under: Main menu /Measurement /Monitoring /
Service values /CVMMXN
312
IEC 61850
identification
CMSQI
VMSQI
VNMMXU
Several instances of each type of measurement function blocks are available in the IED.
The actual reported values from the IED are dependent on the logic configuration made
in PCM600.
© 2017 - 2023 Hitachi Energy. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
-
Isqi
IEC15000113 V1 EN-US
-
Usqi
IEC15000114 V1 EN-US
-
UN
IEC15000115 V1 EN-US
Railway application RER670
1MRK506375-UEN Rev. N
SEMOD54488-4 v13
Application manual