JTA-3: EM-ambient site survey of industrial environments

Transcription

1 JTA-3: EM-ambient site survey of industrial environments Frank Leferink (University of Twente/THALES Netherlands) 1 With contributions from Veronique Beauvois (Liege), Johan Catrysse (Oostende), Sven Battermann (Hannover)

2 Frank Leferink : EMC engineer in EMC laboratory of Hollandse Signaalapparaten (then part of Philips) (5000 empl.). Hollandse Signaalapparaten was sold to Thomson-CSF in Thomson-CSF acquired also Racal, Pilkington, parts of Alcatel, Ferranti etc. etc. and changed name in 2001: THALES Mid 90s: Technical Authority EMC Thales Nederland End 90s: was asked to start education and research in EMC at the University of Twente (UT). The UT is one of the three technological research universities in The Netherlands. This was, and is, a part-time activity. 2000: Became Manager of the Common Expert Team on EMC, comprising all EMC engineers within the Thales group (75 100) 2003: was appointed as full professor EMC (part-time)

3 Research interests and projects 3 Interested in: Special measurement techniques, such as reverberation chambers (example: Triple-TEM cell, Vibrating Intrinsic Reverberation Chamber) EMI at PCB/IC level (example: inductance of ground planes, asymmetry power planes, power distribution networks) Design-for-compliance (example: EMI in electrical drives) Current projects (among others): Innovative Research Project on Power Converters (2 PhD) Innovative Res. Proj. on Embedded Passives & metamaterial (2 PhD) Marie Curie project on embedded antennas (1 post-grad) Marie Curie project on power planes at PCB level (1 post-doc) Marie Curie project on modeling of EM fields in enclosed environments (with Univ. of Nottingham, Torino and Split) Thales projects (many, classified)

4 University of Twente 4 Was founded in 1961 and offers education and research in areas ranging from public policy studies and applied physics to biomedical technology. Faculties: Electrical Engineering, Mathematics and Computer Science (EEMCS) (656 employees, 1500 students) Science and Technology (TNW) (655, 1300) Engineering Technology (CTW) (261, 1700) Behavioral Sciences (GW) (236, 1500) Management and Governance (329, 2000) Note: EEMCS and Science&Technology have large staff because of the many research activities

5 5 Aerospace 25% Defence Security Air Land Naval Joint 25% Thales 50%

6 Thales: innovation and technology 70,000 employees worldwide, >60% engineers 25,000 researchers on cutting-edge technologies Over 12bn annual revenues R&D at Thales totals 2.2bn (18% of revenues) 300 inventions per year Over 15,000 patents Over 30 cooperation agreements with universities and public research laboratories in Europe, USA and Asia 6

7 Background EM(C) in enclosed environments and around large structures Common problems many wavelengths, and limits in computational electromagnetics Examples of enclosed environments 7

8 Fundamental problem: ambient noise level The knowledge of the ambient noise is of interest in Planning and setting up wireless datacommunications (in industrial applications) and to estimate the risk and impact of electromagnetic interference. Ambient: mainly man-made noise Very, very limited data available on the EM ambient levels in industrial environments (actually: all enclosed environments) 8 Actions: Collect and compare standards Collect data from external sources Collect data via measurements

9 9 ITU-R P.372-8: Radio Noise References CCIR, World distribution and characteristics of atmospheric radio noise, Report 322, International Radio Consultive Committee, International Telecommunications Union, 1964 ITU-P.534 Method for calculating sporadic-e field strength CCIR, Man-made radio noise, Report 258-5, International Radio Consultive Committee, International Telecommunications Union, 1990 ERC Report 69: Propagation Model CIGRE 36.04: Guide on EMC in Power Plants and Substations ITU 61 WG documents IEC environments CENELEC CLC/TS ( ): Guide for in situ measurements In situ measurement of Disturbance emission Australia: DSTO-TR-0855, A Comparison of DSTO and DERA HF Background Noise Measuring System with the International Radio Consultative Committee (CCIR) Model Data (2000) US: NRaD TD 2813: CCIR Report 322 Noise Variation Parameters (1995) US: NTIA Report : Broadband Spectrum Survey at Denver, Colorado, Sanders-Lawrence, (1995) US: NTIA Report : The natural and man-made noise environment in personal communications services bands, Spaulding (1996) US: NTIA Report , Man-Made noise measurements (2001) Japan, Radio Noise Measurements and Related Standards, Sugiura (2003) Belgium: Study and simulation of the ambient noise of an industrial environment for wireless communication applications, Catrysse-Rayee, Degrendele (2005) Netherlands: Radio Noise Measurements-European harmonisation of measurement methods (2005) Spain: Novel Procedure to Determine Statistical Functions of Impulsive Noise, Torio-Sanchez (2005) Sweden: Measurements of Man-Made Noise at VHF, Rantakko-Lofsved-Alexandersson (2005) UK: RA(OfCom) AY 3952: Feasibility Study into the Measurement of Man-Made Noise (2001) UK: RA(OfCom) AY4119: Man-Made Noise Measurement Programme (2003) UK: Man-Made Noise Measurement Programme, Wagstaff-Merricks, IEE Proc.Comm(2005) Etc. etc. etc.

10 Examples of the impact of the work: 2.45 GHz WLAN spectrum WLAN, 2.4 GHz. The third nonoverlapping channel is used for data transmission, channel 11. The other channels get polled to check if there are other clients trying to connect. BlueTooth spectrum Due to the hopping of the signal and the fact that the frequency hops cover the entire spectrum, the Bluetooth spectrum looks very flat. Signal generator 10 Microwave oven (kitchen)

11 Intentional EMI test Throughput no interference Bluetooth WLAN Non-reflecting environment WLAN 100% 50% 100% Bluetooth 100% 100% 68% Reflecting environment WLAN Bluetooth 100% 100% 46% 100% 100% 54% Cell phone 1.8 GHz 80% 85% 73% 85% Microwave oven 51% 17% 44% 0% Intentional signal 0% 15% 0% 0% 11 Published at the EMC Europe Conference, 2004

12 12 Interence of electronics in bus (??)

13 13 Polluted EM spectrum: looking for best reception

14 Polluted EM Spectrum: 8 billion cost. GPS receivers disturbed in urban areas 14 Second version: sensor connected with wheels, so when position lost, then still counting kilometers

15 15 Polluted EM Spectrum: at EMC Europe 2006

16 16 Industrial environments

17 Conclusion on available data There is a limited amount of information regarding man-made noise data. It was recorded before digital systems were deployed It was recorded at limited bandwidths and at frequencies below 900MHz. The currently available models (ITU or other) have value but are likely not to be sufficient for digital modulation methods. There is a need to produce models, representative of current environmental conditions, and with appropriate bandwidths (and therefore timeresolutions) commensurate with current technology. 17

18 What is MMN Man Made Noise (MMN): White Gaussian Noise (WGN) and Impulsive Noise (IN), most of it is Class B noise, typically made up of very short impulses that are very wideband and are frequently man-made in origin. The class includes impulses from automotive ignition circuits, thermostats, lighting, etc. Measurements cumbersome: remain at fixed frequency and (time-domain) sampling the IF Dedicated to establishing the noise floor for services 18 But results have not been used to establish the EMI limits..

19 Noise levels in ITU P.372 F a (db) A C B FIGURE 3 F a versus frequency (10 8 to Hz) D E (0 ) E (90 ) F t a (K) (1 GHz) 1 Frequency (Hz) A: estimated median business area man-made noise B: galactic noise C: galactic noise (toward galactic centre with infinitely narrow beamwidth) D: quiet Sun (½ beamwidth directed at Sun) E: sky noise due to oxygen and water vapour (very narrow beam antenna); : upper curve, 0 elevation angle; lower curve, 90 elevation angle F : black body (cosmic background), 2.7 K minimum noise level expected

20 Noise levels in CCIR 322 Noise Figure above ktb [db] Atmospheric Noise Figure, Northern Hemisphere [db] Atmospheric Noise Figure, Atlantic Ocean [db] Urban Man-made Noise Figure [db] Suburban Man-made Noise Figure [db] Galactic Noise Figure [db] Typical Receiver Noise Figure [db] Frequency [MHz] 20

21 21 But in our EMC basic standard.

22 But in our EMC basic standard. And also (from IEC ): In other respects the environment will be the same as described for residential and commercial environments Rationale for this statement????? What about industrial environments? 22

23 23 Measurement data UK Ofcom 2003 Netherlands: 1997, 1999, 2005 Belgium 2005 Japan Other??

24 24 RA(OfCom) report AY 4119

25 Conclusion UK study The mean values of Fa observed during this study appear significantly higher than the median values given in [P.372]. The best explanation available for this is that the number of electronic and electrical devices has grown dramatically in the UK over the past few decades. Whilst EMC legislation has suppressed the IN emissions from automotive sources, there is a general background of WGN that is possibly caused by the incoherent summation of the radiation from hundreds of pieces of equipment. If so, then this is an important finding that should be verified by further tests. 25

26 Measurements To establish noise floor for services: fixed frequency, and measure IF (CISPR proposed APD detector) receiver computer ADC Needed for establishing the influence of noise on specific services 26 EMI: scan of whole spectrum needed In this presentation: focus on the EM field strength at various locations (so no APD yet, no focus on protection of services, yet)

27 Measurements Students Clean power: Static converter in a faraday box 27 Measurements performed by members: Catrysse Beauvois Leferink Batterman Roc H

28 Experiments in The Netherlands: dec [dbµv/m] MM noise 30M 40M 50M 70M 100M 200M 300M 400M 600M 1G [Hz] transmitter (not in this study)

29 Experiments in The Netherlands: dec 1999 From a Thales report 1999: 'The noise levels and resulting radiated emission levels presented in Figure 2 (ITU) are based on the studies performed around Comparing these levels with our measurement results obtained in nowadays urban and suburban environments in 1997 and 1999 we can observe an increase of approximately 20dB This conclusion is in line with the Ofcom report (shown some sheets before) 29

30 30 Experiments on Atlantic (also industrial ): 2005

31 Experiments on Atlantic (also industrial ): Receiver noise level [dbuv] Frequency [MHz]

32 Experiments in The Netherlands: july 2005 Veldsterkte (dbµv/m) Ambient Ambient Ambient Ambient Frequentie (MHz)

33 33 Experiments in Belgium: 2005, 2006

34 Measurement results Belgium 2006 (Anne Roc H) Level (dbuv) E hor Urban Man Made Noise Sub Urban Man Made Noise Galactic Noise Atmospheric Noise E horizontal KHBO Outside F (MHz)

35 Measurement results Belgium 2006 (Anne Roc H) Environment Machne Off-Current on Machine on-current on Urban Man Made Noise SubUrban Man Made Noise Galactic Noise Atmospheric Noise

36 Measurement results Belgium 2006 (Anne Roc H) Urban Man Made Noise SubUrban Man Made Noise Galactic Noise Atmospheric Noise

37 Measurement results Belgium 2006 (Anne Roc H) Urban Man Made Noise -20 SubUrban Man Made Noise Galactique Noise Atmospheric Noise

38 Conclusions The levels are again as already seen before: 20 to sometimes more than 40 db higher than stated in the old ITU and IEC standards If new services are introduced based on the old levels, then serious link problems could occur Wireless data transmission (433 MHz etc.) systems are already disturbed Coverage broadcast and C2000 (400 MHz) much lower than predicted 38 And: The EMC Directive failed! Example: the product directive for frequency converters allows actually any emission level

39 39 From IEC

40 From IEC And: 40 Because this is a harmonised standard, CE mark is applied, and suppliers do not provide a guide for installation and use, including recommended mitigation devices..

41 It is even worse. 41 Measured ourselves, highest level around 200 khz, 130 dbμv (= 3V!!) Difference is 85 db!!! Later the supplier (from Finland) explained the results were obtained after modification. Nonsymmetrical Noise voltage [db0v] From supplier frequency converter, highest level around 10 MHz, appr. 45 dbμv Frequency [MHz] Measured, corr. with MIL-E BWs

42 42 Questions?

43 43