Iec 62236 2 2008

IEC 60050-161, International Electrotechnical Vocabulary IEV – Chapter 161: Electromagnetic compatibility EMC IEC 62236-1, Railway applications – Electromagnetic compatibility – Part 1

Emission from the open railway route during train operation

Emission limits for the frequency range of 9 kHz to 1 GHz are illustrated in Figure 1, with the measurement method specified in Clause 5 For non-electrified lines, these limits align with those established for 750 V d.c.

Annex C provides guidance values for the typical maximum field strengths at the fundamental frequency of various electrification systems These values are influenced by several geometric and operational parameters, which can be sourced from the infrastructure controller.

For urban vehicles operating in city streets, the emission limits given in Figure 1 for 750 V d.c conductor rail shall not be exceeded

There are limited external radio services operating between 9 kHz and 150 kHz that could interfere with railway operations If it can be proven that compatibility issues do not arise, emissions exceeding the specified limits in Figure 1 may be permissible.

NOTE 2 It is not possible to undertake complete tests with quasi-peak detection due to the reasons stated in

Radio frequency emission from railway substations

Radio frequency noise emission from the railway substation to the outside environment measured according to the method defined in Annex A shall not exceed the limits in Figure 2

The limits are defined as quasi-peak values and the bandwidths are those used in

Bandwidth frequencies up to 150 kHz 200 Hz frequencies from 150 kHz to 30 MHz 9 kHz

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU. frequencies above 30 MHz 120 kHz

The distance of 10 m defined in Annex A shall be measured from the fence of the substation

If no fence exists, the measurements shall be taken at 10 m from the apparatus or from the outer surface of the enclosure if it is enclosed

Emission of trains shall not enter into the measurement

There are limited external radio services functioning between 9 kHz and 150 kHz that could potentially interfere with railway operations If it can be proven that there are no compatibility issues, emissions exceeding the specified limits in Figure 2 may be permissible.

NOTE 2 For other kinds of fixed installations like auto-transformers, the same limit and measuring distance shall be applied

5 Method of measurement of emission from moving trains

The method of measurement is adapted from the CISPR 16-1-1 to a railway system with moving vehicles The background to the method of measurement is given in Annex B

Electromagnetic fields produced by rail vehicles on railway networks are assessed using field strength meters set to various frequencies Measurements include the horizontal magnetic field component perpendicular to the track, as well as both vertical and horizontal components of the emitted electric field parallel to the track.

Measurement parameters

The peak measurement method is employed, requiring a duration at the selected frequency that is adequate for obtaining precise readings For optimal accuracy, a recommended duration of 50 ms is suggested, depending on the measuring set used.

5.1.2 Frequency bands and bandwidths at –6 dB used for measurements are in accordance with CISPR 16-1-1

Frequency bands: 9-150 kHz 0,15-30 MHz 30-300 MHz 300 MHz -1 GHz

Bandwidth: 200 Hz 9 kHz 120 kHz 120 kHz

5.1.3 When connected to the antenna, the error of measurement of the strength of a uniform sine-wave field shall not differ more than ± 4,0 dB from CISPR 16-1-1 equipment

To accurately capture the maximum noise levels from a traction vehicle, the measuring equipment must remain active for an adequate period both before and after the vehicle passes the measurement point, as the peak noise may occur at a distance rather than at the point of closest approach.

5.1.5 To cover the full frequency range, antennas of different design are required Typical equipment is described below:

– for 9 kHz to 30 MHz, a loop or frame antenna is used to measure H field (see Figure 3);

– for 30 MHz to 300 MHz, a biconical dipole is used to measure E field (see Figure 4);

– for 300 MHz to 1,0 GHz, a log-periodic antenna is used to measure E field (see Figure 5)

Calibrated antenna factors are used to convert the terminal voltage of the antenna to field strength

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

The optimal distance for the measuring antenna from the track's centerline, where the vehicle operates, is 10 meters For the log-periodic antenna, this distance is specifically measured to the mechanical center of the array.

Conducting two tests to assess both sides of the vehicle is unnecessary, even with different apparatus on each side, as most emissions occur from the sliding contact when the train is in motion.

When tests are conducted at a site that fulfills all recommended criteria except for the antennas being less than 10 meters from the track centerline, the results can be adjusted to reflect an equivalent 10-meter value using a specific formula.

E x is the measured value at D m; n is a factor taken from the table below

0,15 MHz to 0,4 MHz 1,8 0,4 MHz to 1,6 MHz 1,65

The measured values (at the equivalent 10 m distance) shall not exceed the limits given in

Figure 1 for the appropriate system voltage

In situations where the railway's physical layout obstructs the use of reference distances, a suitable method must be established to accommodate the specific conditions For instance, in tunnel environments, miniature antennas can be installed on the tunnel walls It is essential that the chosen limits consider the measurement method employed.

The antenna center height must be between 1.0 m and 2.0 m for loop antennas, and between 2.5 m and 3.5 m for dipole or log-periodic antennas If the ground level at the antenna deviates from the rail level by more than 0.5 m, this discrepancy should be documented in the test report.

The loop antenna must be oriented vertically and aligned parallel to the track The biconical dipole should be positioned along both the vertical and horizontal axes Additionally, the log periodic antenna needs to be set up to capture signals in both vertical and horizontal polarization, aimed directly at the track.

Figures 3, 4 and 5 show the positions and vertical alignments of the antennas

In elevated railway systems, if the specified antenna heights cannot be met, the antenna center height can be referenced to ground level instead of rail level The conversion formula from section 5.1.6 should be used, where D represents the slant distance between the train and the antenna It is essential that the train is visible from the antenna's location, and the antenna's axis must be directed towards the train For highly elevated railways, a measurement distance of 30 meters from the track centerline is recommended All details of the test configuration must be documented in the test report.

When conducting tests on a railway with an overhead electrified supply, measurements should be taken at the midpoint between the support masts of the overhead line, avoiding discontinuities in the contact wire It is important to acknowledge that resonance may occur in the overhead system at radio frequencies, which could necessitate adjustments to the selected measurement frequencies Any instances of resonance should be documented in the test report.

The radio frequency emission will be affected by the state of the railway supply system

Switching feeder stations and conducting temporary works can significantly affect system responses, making it essential to document the system's condition in the test record Ideally, all similar tests should be performed on the same working day When testing near a railway with a track-side conductor rail power supply, it is crucial to position the test location at least 100 meters away from rail gaps to prevent interference from transient fields caused by collector contact Additionally, both the conductor rail and antennas must be situated on the same side of the track.

Test sites do not meet the criteria for a completely clear site due to the presence of overhead structures, rails, and catenaries To minimize interference, antennas should be positioned as far as possible from reflective objects Additionally, if overhead power lines are present, excluding those associated with the railway network, they must be located at least 100 meters away from the test site.

5.1.11 The values measured are expressed as:

These are obtained by using the appropriate antenna factors and conversions

5.1.12 Background noise shall be measured at the test site in the absence of train effects

Measuring noise values from energized power supply conductors is essential If significant noise is detected, it is recommended to conduct measurements at a distance of 100 meters from the test site to identify any high non-railway noise sources.

Frequency selection

Selected frequencies

The selection of the actual frequencies to be measured will depend on the circumstances of the test site

If high signals exist, for example from public broadcasting stations, the selection of test frequencies shall take this into account

It is recommended that test frequencies are selected so that there are at least three frequencies per decade.

Sweep frequency

Due to the limited measurement time during a train passage, employing a sweep frequency measuring technique can effectively capture peak noise levels This method utilizes a peak-hold circuit to provide valuable insights into noise generation as the frequency varies.

The frequency change rate is influenced by bandwidth, which poses timing challenges related to accuracy Typically, a sweep analyzer adjusts its sweep rate to address these issues, making it essential to document both the sweep rate and bandwidth when employing this method.

Transients

During testing, it is important to disregard transients caused by the operation of power circuit breakers when determining the maximum signal level.

Measuring conditions

Weather conditions

To ensure accurate measurements, it is essential to conduct them in dry weather conditions, specifically after a 24-hour period with no more than 0.1 mm of rainfall Additionally, measurements should be taken when the temperature is at least 5°C and wind speeds are below 10 m/s.

Humidity should be low enough to prevent condensation on the power supply conductors

Testing must be planned in advance, even before the weather conditions are known, which means tests will often occur under less than ideal circumstances Consequently, it is essential to document the actual weather conditions alongside the test results.

Railway operating modes

The traction mode is evaluated under two specific test conditions: first, measurements are taken at speeds exceeding 90% of the maximum service speed to incorporate the dynamics of current collection into the noise level, while also operating at the maximum power achievable at that speed Second, assessments are conducted at the maximum rated power and a chosen speed, especially when lower frequencies are a concern.

If the vehicle is capable of electric braking, tests are required at a brake power of at least

80 % of the rated maximum brake power.

Multiple sources from remote trains

For the purpose of limits, the presence of "physically-remote but electrically-near" vehicles out of the test zone is regarded as insignificant when considering radio noise.

Test report

The test report shall contain the following information

– description of railway vehicle (type and configuration);

– graphical results where relevant (the results shall include information such as bandwidths, date, time);

– name of person in charge at site.

Antenna positions

Figure 3 shows the position of the antenna for measurement of the magnetic field in the

9 kHz to 30 MHz frequency band

Figure 4 illustrates the vertical polarization position of the antenna used to measure the electric field within the 30 MHz to 300 MHz frequency range To measure the horizontal field aligned with the track, the antenna is rotated 90 degrees.

Figure 5 illustrates the vertical polarization position of the antenna used to measure the electric field within the 300 MHz to 1 GHz frequency range To measure the horizontal field aligned with the track, the antenna is rotated 90 degrees.

P eak v al ue s 0 20 40 60 80 100 120 10 k H z 100 k H z 1 M H z 10 M H z 1 GHz Frequenc y H z

120 B = 15 kV a.c , 3 kV d.c and 1 ,5 kV d.c C = 750 V and 600 V d c incl udi ng t ram s/ trol ley bu ses f or us e i n c ity s treets A = 20/ 25 kV a.c bw1 bw2 bw3 H f iel d E f ie ld dB ( μ A/ m) dB ( μ V/ m) 75 50

NOTE 1 The discontinuities of the curves are due to changing of the bandwidth of the measurement receiver: bw1 = 200 Hz; bw2 = 9 kHz; bw3 = 120 kHz

NOTE 2 Values are 10 m from the railway track

Figure 1 – Emission limits in frequency range 9 kHz to 1 GHz

Figure 2 – Emission limit for substations

10 m to mechanical centre of antenna

Track on which rolling stock to be tested is running

Printer Sensor: loop antenna for magnetic field H

Figure 3 – Position of antenna for measurement of magnetic field in the 9 kHz to 30 MHz frequency band

Figure 4 – Position (vertical polarisation) of antenna for measurement of electric field in the 30 MHz to 300 MHz frequency band

Figure 5 – Position (vertical polarisation) of antenna for measurement of electric field in the 300 MHz to 1 GHz frequency band

Method of measurement of electromagnetic emission from railway substations

Given the unique geometry of railway traction supply systems, it is essential to establish the criteria for measuring electromagnetic field emissions during standard load conditions.

Railway substations experience significant fluctuations in load over short periods As emissions are linked to these load variations, it is essential to monitor the actual loading of the substation during emission testing.

Emission measurements will be conducted at a distance of 10 meters from the outer fence of the substation, specifically at the midpoints of three sides, excluding the side facing the railway, unless this side is over 30 meters from the nearest electrified railway track's center In such cases, measurements will include all four sides Additionally, if any side of the substation exceeds 30 meters in length, measurements will also be taken at the corners.

The accuracy of the measuring equipment for the radio frequency tests shall not differ by more than ± 4,0 dB from the requirements of CISPR 16-1-1

At each measurement location, it is essential to assess the maximum radio emission near 1 MHz using a vertical plane loop antenna, ensuring the antenna's orientation is recorded The substation must operate at a minimum of 30% of its rated load during this measurement, with the loop antenna positioned 1 to 1.5 meters above the ground Additionally, radio emissions should be evaluated across the frequency range of 9 kHz to 30 MHz, again with the loop in its optimal orientation, while maintaining the substation's load at no less than 30% of its rated capacity.

The fixed antenna position may yield values below the absolute maximum at certain frequencies Maximum radio emissions from 30 MHz to 300 MHz are typically measured using a vertical dipole or vertical biconical antenna, with the substation loaded to at least 15% of its rated load and the antenna center positioned 3 m above ground For frequencies around 350 MHz, emissions are measured with a vertically polarized log-periodic antenna, ensuring the substation is also loaded to a minimum of 15% of its rated load and the antenna is 3 m above ground Additionally, radio emissions from 300 MHz to 1 GHz are measured with a log-periodic antenna in its optimal orientation, maintaining the same loading and height requirements.

Background to the method of measurement

This annex outlines a method for measuring electromagnetic noise generated by a railway network during the movement of railway vehicles Current measurement techniques are deemed inadequate due to the high speeds at which these vehicles operate.

IEC 62236-3-1 addresses the evaluation of stationary and slow-moving vehicles, including both traction and trailer vehicles, as trailers may house electric equipment that emits noise It is essential to assess diesel traction vehicles due to potential sources of radio emissions This standard provides a method for assessing the electromagnetic spectrum disturbance caused to other users Additionally, it outlines a reference measurement method for accurate evaluation.

B.2 Requirement for a special method of measurement

For frequencies above 9 kHz, there is a standard method of measuring radio fields and this is described in CISPR 16-1-1

A railway network requires a specialized measurement method due to its unique characteristics, such as the high-speed movement of the source and the potential radiation emitted from the extensive antenna created by the electrical supply conductors of an electrified railway.

The example given in Figure B.1 shows the time variation of emission from a moving train with many transient events

This method of measuring railway noise does not follow the quasi-peak method of CISPR 16-

The CISPR 16-1-1 method is insufficient for identifying the full range of disturbances affecting nearby systems, as it primarily focuses on protecting radio communication from interference without considering electronic safety systems used in critical areas like railways and airports To align with local industry needs and ensure comprehensive safety, peak detection methods must be applied alongside this standard, necessitating realistic simulation exercises However, implementing double testing for railways could present significant challenges.

Establishing a precise correlation between the values derived from peak and quasi-peak measurement methods is challenging due to the continuous sinusoidal disturbances from vehicle operations and the pulsed signals from sources like pantograph/overhead line contact Nonetheless, it is important to note that, as per CISPR 16-1-1 standards, the measurements obtained using a peak detection system will always be greater than or equal to those from a quasi-peak system.

B.3 Justification for a special method of measurement

Fields are not measured using the method of CISPR 16-1-1, but are made with peak detection within a short time window, 50 ms being recommended, at the selected frequency because:

This approach provides a more accurate representation of the effects on electronic or computer systems, as opposed to the quasi-peak detection weighting principles, which primarily reflect interference related to radio transmission The 50 ms time window effectively captures peak emissions from alternating current (a.c.) railways, which typically occur during current reversals At a frequency of 16.7 Hz, these reversals happen every 33 ms, ensuring that at least one reversal is detected within the 50 ms window.

Quasi-peak detector systems can take up to 1 second to respond due to the limitations of galvanometer-type instruments, which is excessively slow for applications involving moving trains.

– it gives the maximum value that could be measured with the method of CISPR 16-1-1 and is representative of the "worst possible case" for interference to radio transmission

While railway vehicles and sliding contact current collection contribute to noise above 1 GHz, their emission levels are relatively low, and the attenuation with distance is significant Consequently, there are currently no proposals for measurements in this frequency range.

Bandwidths other than those given in 5.1.2 are available in suitable measuring equipment, such as 300 Hz for the 9 kHz to 150 kHz band, and 7,5 kHz or 10 kHz for 0,15 MHz to

Tiêu đề	Electromagnetic Compatibility of Railway Systems: Emission of the Whole Railway System to the Outside World
Trường học	International Electrotechnical Commission
Chuyên ngành	Railway applications – Electromagnetic compatibility
Thể loại	International Standard
Năm xuất bản	2008
Thành phố	Geneva

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Số trang	54
Dung lượng	1,15 MB