IEC TR 60919-1:2010/AMD1:2013
(Amendment)Amendment 1 - Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions
Amendment 1 - Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions
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Standards Content (Sample)
IEC/TR 60919-1
®
Edition 3.0 2013-04
TECHNICAL
REPORT
AMENDMENT 1
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 1: Steady-state conditions
IEC/TR 60919-1:2010/A1:2013(E)
---------------------- Page: 1 ----------------------
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IEC/TR 60919-1
®
Edition 3.0 2013-04
TECHNICAL
REPORT
AMENDMENT 1
Performance of high-voltage direct current (HVDC) systems with line-
commutated converters –
Part 1: Steady-state conditions
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
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ICS 29.200; 29.240.99 ISBN 978-2-83220-738-3
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – TR 60919-1 Amend. 1 IEC:2013(E)
FOREWORD
This amendment has been prepared by subcommittee 22F: Power electronics for electrical
transmission and distribution systems, of IEC technical committee 22: Power electronic
systems and equipment.
The text of this amendment is based on the following documents:
DTR Report on voting
22F/277/DTR 22F/286A/RVC
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
_____________
CONTENTS
Replace, the titles of Clause 19 and its subclauses as follows:
19 Radio frequency interference
19.1 General
19.2 RFI from HVDC systems
19.2.1 RFI sources
19.2.2 RFI propagation
19.2.3 RFI characteristics
19.3 RFI performance specification
19.3.1 RFI risk assessment
19.3.2 Specification RFI limit and its verification
19.3.3 Design aspects
Add the title of Annex A as follows:
Annex A (informative) Factors affecting reliability and availability of converter stations
Replace, in the list of figures, the title for Figure 23 as follows:
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TR 60919-1 Amend. 1 IEC:2013(E) – 3 –
Figure 23 – RY COM noise meter results averaged – Typical plot of converter noise levels on
the d.c. line corrected and normalized to 3 kHz bandwidth – 0 dBm = 1 mW corresponding to
0,775 V at a pole-to-pole surge impedance of 600 Ω
Add, in the list of figures, the title for Figure 25 as follows:
Figure 25 – Recommended measurement procedure with definition of measuring point
Figure 7 – Bipolar system
Replace Figure 7 by the following new figure:
I
d
(+)
1 1
2 2
F F
U
d
3 3
U
d
2 F F 2
1 (–) 1
IEC 807/13
Key
1 DC reactor
2 DC filter
3 Earth electrodes
Figure 7 – Bipolar system
Figure 10 – Bipolar system with two 12-pulse units in series per pole
Replace Figure 10 by the following new figure:
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– 4 – TR 60919-1 Amend. 1 IEC:2013(E)
1
2
2
1
3
1
3
2
2
1
IEC 808/13
Key
1 DC reactor
2 By-pass switch
3 DC switch
Figure 10 – Bipolar system with two 12-pulse units in series per pole
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TR 60919-1 Amend. 1 IEC:2013(E) – 5 –
Figure 11 – Bipolar system with two 12-pulse units in parallel per pole
Replace Figure 11 by the following new figure:
1 1
1 1
1 1
1 1
IEC 809/13
Key
1 DC reactor
Figure 11 – Bipolar system with two 12-pulse units in parallel per pole
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– 6 – TR 60919-1 Amend. 1 IEC:2013(E)
10.2.2 Electrical parameters
Replace, in item 1) the words “100 Hz” by “two times of the fundamental frequency”.
Replace, in item 3) the words “100 kHz” by “two times of the fundamental frequency”.
11.1 General
Add, in the second paragraph after the second sentence ending “…. during the acceptance
period of an HVDC system.” the following new sentence:
Please refer to Annex A for more information on factors affecting reliability and availability of
converter stations.
13.6 Optical fibre telecommunication
Add the following new sentence at the end of the third paragraph:
Use of OPGW (optical ground wire) as one of shielding wire is another typical arrangement
used in many overhead lines schemes.
18.1 General
Replace the third paragraph by the following new paragraph:
Field experience shows that thyristor valves generate about 10 dB to 15 dB less conducted
noise interference than mercury arc valves.
18.2 Performance specification
Replace the fifth paragraph by the following new paragraph:
Where dBm is defined as a means of interference measurement in which 0 dB is specified to
1,0 mW, which corresponds to 0,775 V pole-to-pole interference voltage assuming a line to-
line surge impedance of 600 Ω. In a 50 Ω cable on the low voltage side, 0 dBm and 1 mW
corresponds to 0,224 V.
Add the following new sentence at the end of the sixth paragraph after "…should be
evaluated":
It should be considered that the cost for a broad band PLC filter is significantly higher than
the cost for a narrow band PLC filter. Especially, filters for the lower frequencies
20 kHz to 50 kHz cost significantly more than PLC filters for higher frequencies.
Figure 23 – RY COM noise meter results averaged – Typical plot of converter noise
levels on the d.c. line corrected and normalized to 3 kHz bandwidth – 0 dBm = 0,775 V
Replace the existing title of Figure 23 by the following new title:
Figure 23 – RY COM noise meter results averaged – Typical plot of converter noise
levels on the d.c. line corrected and normalized to 3 kHz bandwidth – 0 dBm = 1 mW
corresponding to 0,775 V at a pole-to-pole surge impedance of 600 Ω
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TR 60919-1 Amend. 1 IEC:2013(E) – 7 –
19 Radio interference
Replace the title and text of Clause 19 by the following:
19 Radio frequency interference
19.1 General
Historically Radio Frequency Interference (RFI) from high voltage electric power installations
has been related to interference with AM broadcast distribution due to high voltage a.c. line
corona. Consequently, this aspect is covered well in the literature and in relevant standards,
i.e. the CISPR 18 series. RFI from substations has been of minor practical concern. Therefore
very little has been documented regarding RFI from HV and MV substations. However, CIGRÉ
Technical Brochure No. 391, provides a thorough analysis of the aspect related to RFI from
substations, including HVDC substations. The analysis is based on both theory and
measurement results.
One important aspect that is treated in the Technical Brochure (TB) is the attenuation of the
RFI versus distance, including how the attenuation depends on the frequency.
RFI relates to a quite wide frequency range. According to CISPR 11 frequencies between
9 kHz and 400 GHz may be used for wireless communication and are therefore covered by
the International Telecommunication Union (ITU) current international table of frequency
allocations. Consequently, electromagnetic interference in this frequency range is defined as
Radio Frequency Interference (RFI). However, the frequencies below 150 kHz are nowadays
sparsely used and the standards for frequencies above 1 GHz are under development.
19.2 RFI from HVDC systems
19.2.1 RFI sources
RFI energy at the HVDC substation is produced by the turn-on and turn-off sequences in the
valves, from corona on the high voltage switchgear and lines, and from sparking and gap
discharge activities within the switchyard.
The RFI noise from the valve operation is predominantly produced by the fast voltage collapse
during the turn-on sequence. These transients excite localized resonance circuits formed by
stray capacitance and inductive elements in the bus structures, bushings, reactors, converter
transformers, etc.
RFI generated by the a.c. corona in the high voltage a.c. switchyard of the HVDC substation
varies significantly with the weather conditions and is highest at bad weather. RFI generated
by d.c. corona is highest near the positive conductor and decreases with the radial distance
from the conductor. DC corona does not vary very much with the weather conditions and is
somewhat higher at fair weather.
Recent measurements have indicated that there may be a significant high frequency RFI from
the a.c. part of a substation, especially at dry weather conditions if the substation is old. This
high frequency RFI noise is considered to be generated by gap discharge and/or sparking
activities. For more information reference is made to CIGRÉ TB No. 391.
19.2.2 RFI propagation
RFI generated in the HVDC substations may propagate as:
a) a guided wave transmission propagating along the HVDC transmission line;
b) a guided wave transmission propagating along the a.c. transmission lines;
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– 8 – TR 60919-1 Amend. 1 IEC:2013(E)
c) direct wave radiation from the HVDC substation.
The attenuation of the RFI versus distance varies with the frequency as follows.
a) The attenuation for the line-to-earth mode of RFI propagating along the lines is in the
0,8
order of 3f dB/km with f in MHz. The attenuation varies with line design parameters and
the soil resistivity.
b) The attenuation for the line-to-line mode of RFI propagating along the lines is in the order
0,8
of 0,3f dB/km with f in MHz. The attenuation varies with line design parameters and the
soil resistivity.
c) The physics for attenuation of the direct wave RFI with distance is quite complex. As an
approximation, at a distance from a substation shorter than λ/2π or longer at a certain
2
distance d(SA) the attenuation of the field strength decreases as 1/r (where λ is the
wavelength of the EM radiation and r is the distance to the installation). For intermediate
distances, the attenuation is proportional to 1/r. The distance d(SA) depends on the
frequency, the height of the antennas and the soil properties. For more information
reference is made to CIGRÉ TB No 391. For a realistic example in the TB, the distance
d(SA) is in the order of 25 m at 50 MHz and increases linearly with the frequency for
higher frequencies. For lower frequencies than 50 MHz, the distance d(SA) varies as 1/f.
The implication of the above is that for RFI propagating along the lines, the high frequency
RFI vanishes after a few kilometres, especially the line-to-earth component that is dominating.
However, low frequency RFI will propagate quite a long distance, especially the line-to-line
component.
Within a few hundred meters from the substation, the direct wave RFI can have a quite broad
frequency range. However, when normal design is applied, the RFI has diminished to the
background RFI level after 0,5 km to 1 km.
19.2.3 RFI characteristics
The general characteristic of the RFI noise from an HVDC substation is repeated transients
regardless that the noise is produced by the commutation process, corona, sparking or gap
discharge. Due to the different sources the frequency characteristics of the broad band RFI
from a converter station can be quite complex and very irregular. To some extent this is valid
for any high voltage substation.
RFI noise generated by the commutation process of the HVDC converter has the following
characteristics.
a) Interference energy is directly proportional to the magnitude of the voltage jumps
produced during the turn-on sequences of the valves and also depends on circuit
parameters. The voltage jumps at turn-off has less impact as the rise time at turn-on is
much shorter than the rise time at turn-off.
b) As the RFI due to the converter commutation process depends on the circuit resonances,
the frequency spectrum is quite irregular.
c) Due to the defined rise time for the voltage jumps at turn-on, the RFI due to the
commutation process decays for frequencies above 1 MHz and is negligible for
frequencies above 10 MHz.
d) The noise that comes out from the valve hall is predominantly the noise conducted through
the wall or transformer bushings if the valve hall is designed with good RF shielding.
e) The noise level is essentially independent of the operating current.
f) The number of converters has minor impact on the noise level.
The dominant mode for all RFI generated in a substation is the line-to-earth mode.
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TR 60919-1 Amend. 1 IEC:2013(E) – 9 –
19.3 RFI performance specification
19.3.1 RFI risk assessment
The process for the specification should start with an RFI risk assessment regarding any local
conditions requiring specific precautions regarding RFI. It should be noted that the risk for
interference is related to nearby radio receivers, not to nearby radio transmitter. A nearby
airport may imply an extra risk for RFI with the airplanes approaching the airport for landing.
Of special concern is interference related to the non-directional beacons (N DB) as their
operating frequency is coincident with the frequency range for the converter RFI emission.
Also local communication centres with dual communication such as fire brigade stations
should be considered in the risk assessment.
The important factors are: Frequencies used, the bandwidth, the signal level, the noise to
signal requirement and the distance to and the location of the antenna of the radio receivers.
19.3.2 Specification RFI limit and its verification
The specified RFI requirement should include all sources related to the relevant delivery. The
specification shall define all steady state operation modes and conditions and weather
conditions during which the criteria shall be met.
Basically a single basic criterion shall be specified to be applied to all steady state operation
modes, at any load up to and including the full load rated value, and within the design range
of firing angle and all weather conditions is recommended. The performance criterion should
cover the normal a.c. and d.c. operating voltage ranges. For practical reasons, then overall
verification of the RFI performance by measurements shall be performed under fair weather
conditions while the RFI emission due to a.c. corona under bad weather conditions shall be
verified by calculation.
The requirement shall be specified as a graph of the maximum E-field in dB[µV/m] versus
frequency for the entire frequency band 0,9 kHz to 1 GHz. There should be one graph for the
substation limit and one graph for line limits. Suitable limits for the normal cases are given in
CIGRÉ TB No. 391, with justifications.
The recommended procedure for verification by measurements is shown in Figure 25. The
recommendations are detailed in CIGRÉ TB No. 391.
---------------------- Page: 11 ----------------------
– 10 – TR 60919-1 Amend. 1 IEC:2013(E)
T
Substation
limits
4 km
T
Line
limits
T
T
d
3
d
2
d
1 Substation limits
IEC 810/13
T
Key
d measuring distance for substations, normally 200 m for an HVDC substation
1
d measuring distance for lines that is 30 m up to 600 kV a.c. and 50 m for higher voltages
3
d one third of d
2 1
T most relevant positions for measurement
Figure 25 – Recommended measurement procedure with definition of measuring point
The limits for substations in accordance with Table D.2 in CIGRÉ TB No.391:2009 is
applicable both for the contour around the active parts of substations and the closest part of
the contour along the line. After a distance of 4 km, the limits for the line in accordance with
Table D.3 in CIGRÉ TB No.391:2009 apply.
The measurement shall be performed as a frequency scan over the entire RFI frequency
range as the frequency characteristic may be very irregular. It is not sufficient to measure the
RFI level at 0,5 MHz only, as often done for RFI due to a.c. line corona.
19.3.3 Design aspects
The valve-hall building design should incorporate necessary shielding to meet the RFI
requirement without any external switchyard screening. Special attention should be given to
minimizing the antenna area for loops with high frequency transients conducted through the
valve and the transformer bushings.
The specification should require a statement on the proposed method of limiting RFI within
the specified limits. There should also be a statement regarding estimation of the expected
RFI level by calculation during the design stage, within the entire frequency range. This
estimation shall cover both the RFI from the substation and the RFI from the line, as defined
in Figure 25. In this estimation also bad weather a.c. corona within the substation should be
considered.
Add the following Annex:
---------------------- Page: 12 ----------------------
TR 60919-1 Amend. 1 IEC:2013(E) – 11 –
Annex A
(informative)
Factors affecting reliability and availability of converter stat
...
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