ABB Relion 670 Series Applications Manual page 273

1MRK 511 407-UUS Rev. J
• Poor power quality
• Increase in operational cost due to less productivity
• Damage to sensitive equipment in nearby facilities.
Maintaining high power quality in traction system is very complex. The presence of non-linear
loads reduces the capability of the existing harmonic mitigation techniques. However, it is
essential to minimize the issues like harmonics, voltage sags and flicker to protect sensitive
equipment affected by the aforementioned issues produced by traction systems.
Various practical conditions which have dynamic characteristics like the speed of locomotion, load
and line condition will make this problem even worse. Harmonic current increases the heat
dissipation due to hysteresis and eddy currents, which causes stress on insulation materials.
Harmonic current increases transmission loss and the voltage drops.
In general, harmonics can cause reduced equipment life if a system is designed without
considering the harmonics and if the equipment is not designed to withstand harmonics. Hence, it
is important to measure and monitor harmonics in power systems. Harmonic voltage distortions
on 161 kV power system and above is limited to 1.5% of total harmonic distortion (THD), in with
each individual harmonic is limited to 1.0%.
Current harmonic limits vary based on the short circuit strength of the corresponding system they
are injected into. Harmonic current limit defines the maximum amount of harmonic current that
can be inject into the utility system. The difference between THD and TDD is used to calculate the
harmonics level during light load conditions.
16.10.3 Setting guidelines
The recommended limits for total harmonic distortion and individual harmonic distortion are
available in the IEEE 519 standard. The limits are based on measurements which are done at the
point of common coupling. It should not be applied to either individual pieces of equipment or at
locations within a user's facility. In most cases, harmonic voltages and currents at these locations
could be found to be significantly beyond recommended limits at the PCC due to the lack of
diversity, cancellation, and other phenomena that tend to reduce the combined effects of multiple
harmonic sources to levels below their algebraic summation.
16.10.3.1 Setting procedure on the IED
Parameters for CHMMHAI(ITHD) function are set via the local HMI or PCM600.
Common base IED values for primary current (
function GBASVAL.
GlobalBaseSel : It is used to select GBASVAL function for reference of base values.
MaxLoadCurr : Maximum demand load current at PCC for total demand distortion calculation.
When the point of common coupling (PCC) is considered at the service entrance or utility metering
point, IEEE 519 standard recommends that the maximum demand load current must be calculated
as the average current of maximum demand for the preceding 12 months.
Phasor measurement unit RES670
Application manual
Minimum and maximum current limit is set as 5% of the
respectively. If the current is outside the above range, the calculation of total
harmonic distortion, individual harmonic distortion, total demand distortion and
crest factor are blocked and outputs are provided as zero.
© Copyright 2017 Hitachi Power Grids. All rights reserved
IBase ) is set in the global base values for settings
Section 16
Monitoring
GUID-2C07190A-7EEC-43AB-A84C-730550A2A7B0 v1
GUID-45A6724C-1FF0-4910-9878-01518111EB26 v1
GUID-0C108542-C1CF-4B95-AB67-C7424FB5A98E v1
GUID-57719753-00C3-43F6-97B5-AA3B22618A3F v1
GUID-A773AE35-1480-4C07-9894-908229DC3BC7 v1
GUID-F41E3011-637C-46C6-BA99-4F8C48AC79B5 v2
IB and 300.0% of IB
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