CHERRY TREE WIND FARM ELECTROMAGNETIC … · 6. RADIOCOMMUNICATIONS SERVICES 7. EMI EFFECTS OF WIND...

of 36

Cherry Tree Wind Farm Electromagnetic Interference Assessment – Possible Impacts onBroadcasting & Radiocommunications Services

Lawrence Derrick & Associates

CHERRY TREE WIND FARM

ELECTROMAGNETIC INTERFERENCE ASSESSMENT

INVESTIGATION OF POSSIBLE IMPACTS ONBROADCASTING AND RADIOCOMMUNICATION

SERVICES

[Final]

18th April 2012

L. J. Derrick B. E. (Elec.) ACMA Accreditation No 008Lawrence Derrick & AssociatesEngineering Consultants & RF Frequency Assigners

of 36


CONTENTS

1. BACKGROUND

2. INTRODUCTION

3. LEGISLATION AND GUIDELINES

4. DESKTOP STUDY

5. BROADCASTING SERVICES IN THE AREA

6. RADIOCOMMUNICATIONS SERVICES

7. EMI EFFECTS OF WIND TURBINES

8. DISCUSSION OF OVERSEAS EXPERIENCE

9. CHERRY TREE WIND FARM SITUATION

10. AVOIDANCE OF INTERFERENCE DURING CONSTRUCTION

11 WIND MONITORING MAST LOCATIONS

12 POWER INFRASTRUCTURE ELECTRIC AND MAGNETIC FIELDS

13. FORTUITOUS RECEPTION OF BROADCAST SIGNALS

14. MITIGATION TECHNIQUES

15. CONCLUSIONS

ATTACHMENTS

1. Cherry Tree Wind Farm Turbine Co ordinates2. TV Stations & Channels in the Wind Farm Area3. Radio Link Map 40- 999 MHz Frequencies4. Radio Link Map above 1000 MHz Frequencies5. Map of UHF/VHF Link Paths Near Wind Turbines6. Map of UHF/VHF Link Paths Near Wind Turbines - Detail7. Map of Microwave Link Paths Near Wind Turbines8. Map of Microwave Link Paths Near Wind Turbines - Detail9. Path Profile Airservices Microwave Link10. Path Profile Vertical Telecoms UHF Link11. Path Profile CFA. UHF Link12. Path Profile Goulburn Valley Water UHF Link13. Path Profile Vic State Emergency UHF Link14. Radio Link Systems Data and Clearances15. Summary of Radio Path Clearances Required16. Glossary of Technical Terms

of 36


DOCUMENT HISTORY

REV DATE DESCRIPION AUTHOR REVIEWEDDraft1 08/10/2011 1st Draft to

InfigenLJD LJD

Draft2 Rev A 29/02/2012 2nd Draft withAurecon markups, new turblayout. Ref. 12&13 added

LJD LJDAurecon

Draft3 17/04/2012 Minor revs,Attach. 15 issuesresolved. Revisedturb. Coords.

LJD LJDInfigen

Final 18/04/2012 Minor revs, met.mast location

LJD LJD

DISCLAIMER

This Report has been prepared on the basis of ACMA radiocommunicationslicensing data and broadcasting information and other reference material availablein the public domain at the date of production of the report. The Report does notimply that any conclusions are not subject to change.

of 36


1. BACKGROUND

Infigen Energy has engaged Lawrence Derrick & Associates to undertake anElectromagnetic Interference Assessment of the proposed Cherry Tree WindFarm project. The proposed wind farm is located approximately 80 km northeastof Melbourne and approximately 15 km southeast of Seymour. The proposedCherry Tree Wind Farm consists of 16 wind turbine generators located within theMitchell Shire Council Local Government Area. This Report considers thepotential electromagnetic interference impacts of the Cherry Tree Wind Farm onradiocommunications and broadcasting in the area.

The Australian Communications and Media Authority (ACMA) are responsible forthe regulation of broadcasting, the internet, radiocommunications andtelecommunications. A number of existing ACMA registered radiocommunicationservices are located in the general area and five point-to-point radio servicescross the wind farm nominal site boundaries. To ensure that the locations ofturbines will not degrade the performance of radio systems, minimum separationdistances and exclusion zones have been established for the turbine structures.The residences in the area surrounding the wind farm are potentially providedwith TV and FM sound broadcasting services from high power transmitterslocated on Mt Alexander (Bendigo), Mt Major (Goulburn Valley). Medium and lowpower fill-in TV stations at Yarck (Alexandra). Seymour and Yea may also bereceived in some locations near the wind farm. AM Radio broadcasting servicestransmitted from Melbourne, Horsham and other locations also service the area.The TV/Sound broadcasting Licensees providing service to the area have beenidentified facilitating correspondence with the organisations involved to requestcomments on any for seen impacts on these services.

This Report provides an analysis of each of the radio facilities registered near thewind farm and establishes recommended clearances based on accepted industrycriteria for radio links crossing the wind farm and any required buffer zones forother radiocommunications sites. A study of the signal paths from the main TVstations to the area surrounding the wind farm has been carried out to identifyany potential interference to nearby residences. This Report includes anassessment of the proposed wind farm on point-to-point / point-to-multipointmicrowave links, television reception, satellite reception, broadcast AM/FM radio,mobile phones, wireless internet services and global positioning systems.

Comments are also provided on the radio interference and human exposureimpacts from electric and magnetic fields from power lines and powertransmission infrastructure associated with the wind farm.

2. INTRODUCTION

Radiated EMI can potentially be generated from wind turbine generators and theassociated distribution power lines on the site. These issues are also discussedin this report.

It is considered necessary to include an assessment of potential impacts of thewind turbines on TV and sound broadcasting reception in the general area of the

of 36


wind farm from the transmitting stations utilised by residents and to determine ifany of the turbines are close to radio link paths traversing the wind farm site.This report covers the outcomes of a desktop study to identify any potentialissues and makes recommendations on radio link path and radio site clearances.

3. LEGISLATION AND GUIDELINES

3.1 Commonwealth legislation Under the Commonwealth of AustraliaRadiocommunications Act 1992 (Radiocommunications Act), “interference” isdefined as:

• In relation to radiocommunications: Interference to, or with,radiocommunications that is attributable, whether wholly or partly and whetherdirectly or indirectly, to an emission of electromagnetic energy by a device; or

• In relation to the uses or functions of devices: Interference to, or with, thoseuses or functions that is attributable, whether wholly or partly and whether directlyor indirectly, to an emission of electromagnetic energy by a device.

In using these definitions, the Radiocommunications Act deals with theradiocommunications interference caused by electromagnetic fields and providesprotection for users where such interference is caused. It does not, however, dealwith radiocommunications interference caused by physical obstructions.

This report provides best practice guidance about the issues associated with thephysical obstruction impacts of wind turbine structures, and details methods forassessing the potential of such impacts. It also advises which stakeholdersshould be consulted and what sort of information they may require. Mitigationstrategies and post-construction monitoring methodologies are also presented.

3.2 Environment Protection and Heritage Council’s draft National WindFarm Development GuidelinesSome guidance on procedures to resolve EMI issues for wind farm projects hasbeen taken from Appendix F of the Environment Protection and HeritageCouncil’s (EPHC) draft National Wind Farm Development Guidelines (Ref. 9).

3.3 Mitchell Planning Scheme Clause 52.32-5 Decision Guidelines states:“Before deciding on an application, in addition to the decision guidelines ofClause 65, the responsible authority must consider, as appropriate: …

The effect of the proposal on the surrounding area in terms of noise, bladeglint, shadow flicker and electromagnetic interference. …”

3.4 Victorian Planning Guidelines The Victorian Department of Planning andCommunity Development has re-issued the Policy and Planning Guidelines forDevelopment of Wind Energy Facilities in Victoria, dated August 2011. Thisdocument includes references to the need to consider electromagneticinterference issues in the design of wind farms. The Model permit conditions tobe applied as appropriate at Attachment B of the Guidelines provides for a pre-construction survey of TV reception at dwellings within 5 km of turbines.

3.5 Clean Energy Council (Auswind) Best Practice Guidelines TheseGuidelines issued in December 2006 in Appendix 11 also provide guidance on

of 36


the consideration of the potential impact of wind farms on radiocommunicationsand broadcasting.

4. DESKTOP STUDY

A desk top study has been carried out on the likely impact of wind turbinegenerators on broadcasting and radiocommunications in the area surrounding thewind farm. This study is based on relevant International TelecommunicationsUnion (ITU) documents and on other professional reports on overseas andAustralian experience of wind farm impacts on broadcasting services in thevicinity of any wind turbine structures. For radiocommunication services sites upto at least 50 km from the site needs to be considered because of the length ofpoint-to-point paths of up to or exceeding 100 km.

Using data from ACMA’s radiocommunications licensing database (RADCOM),checks have been made on radiocommunication services within at least a 50 kmradius of the proposed wind farm to determine if any of the turbine towers couldobstruct line-of-site paths or have any likely detrimental effect on these services.Clearance criteria for ray lines have been indicated for any point-to-point radiopaths crossing or near the wind farm site.

5. BROADCASTING SERVICES IN THE AREA

From ACMA TV and Sound Broadcasting Station listings, and from a map surveyof the area surrounding the Cherry Tree Wind Farm site, the following is ageneral summary of the broadcast transmitter site locations and radio frequencychannels which provide coverage of the area.

5.1 Analogue and Digital Television

Analogue TV is no longer transmitted in the area however it is possible that a fewresidents may view out-of-area Melbourne analogue or digital TV channels. It isexpected that residents in the area surrounding the proposed wind farm locationgenerally view digital TV from the Bendigo or Goulburn Valley National andCommercial main stations located at Mt Alexander and Mt Major respectively.These stations are approx. 85 and 95 km from the centre of the proposed windfarm. A summary of channels available from the stations listed is shown inAttachment 2. It is also possible that a few residents may be able to view TV fromthe Alexandra, Seymour or Yea medium or low power fill-in stations.

5.2 Analogue Television Cessation

Digital television signals are currently being radiated in parallel with analoguetelevision signals in some areas of Australia including Capital Cities. Under thecurrent programme of transition to digital television in Australia, whichcommenced in 2001, some regional areas including Regional Victoria now nolonger have analogue TV coverage. It is therefore considered that any remedialaction necessary for mitigation of any interference to TV reception would need tofocus on digital transmission of signals.

of 36


5.3 TV Retransmission Stations

From ACMA TV Broadcasting Data there are retransmission stations listed thatmay receive their input signal “off air” from the Goulburn Valley or Bendigo mainstations at Mt Major or Mt Alexander. The Yea station may receive off air from theSeymour station. The potential interference issue is that the path to some ofthese stations may pass through the wind farm potentially causing interference tothe signal which is retransmitted. This is discussed below.

5.4 FM Sound Broadcasting

Bendigo and Goulburn Valley FM Services radiated from Mt Major and MtAlexander service the general area. It is unlikely that these services will beaffected by the proposed wind farm project. FM Stations covering this area havetherefore not been listed. There are also a number of lower power local FMstations listed in the area however the transmitting sites are located at sufficientdistances to not have coverage impairment issues.

5.5 AM Sound Broadcasting

Some Melbourne and Horsham AM medium frequency (MF) stations will bereceivable in the general area. As indicated below, wind farm effects on MF radioare highly unlikely and therefore the stations serving the area have not beenlisted in detail.

5.6 Satellite Pay Television

Some dwellings in the area may have satellite pay TV or “Free-to-Air” serviceinstallations. Unless a particular subscriber’s antenna reception direction andsatellite antenna angle of elevation is closely aligned with a turbine, which ishighly unlikely, no impacts on TV reception are expected.

6. RADIOCOMMUNICATIONS SERVICES

The wind turbine current grid coordinates for Cherry Tree are listed in Attachment1. Maps generated from data in the ACMA database are shown in Attachments 3& 4. Attachment 3 shows all radio sites and point-to-point links within at least 50km of the proposed wind farm and with operational frequencies in the range 40 –999 MHz (VHF & UHF). Attachment 4 is a similar map for links in the frequencyrange above 1 GHz (microwave). It should be noted that due to the close spacingof adjacent link sites the site number displayed on the PDF maps may not be theappropriate one for a given point-to-point link due to overlaying of site labels. Thewind farm nominal envelope is shown as a rectangle and wind turbine locationsare also shown in the close up mapping.

6.1 Point-to-Point

A number of point-to-point links are registered for operation within 50 km of thewind farm site. As shown in the map Attachment 3 there is two UHF link pathswhich cross the boundaries of the proposed wind farm. On one of the paths thereare three separate point-to-point links registered which means there are 4 UHFsystems crossing the wind farm site.

of 36


Attachment 4 indicates that there is one microwave link (> 1GHz) on almost anidentical path with one of the UHF links crossing the proposed wind farm site.Clearance requirements are to be met to ensure turbines are not located close tothe ray lines of these links to avoid any impact on their performance. The raylines passing near the wind turbines are shown in zoomed up maps inAttachments 5, 6, 7 & 8. The source ACMA database contains data for sites inAMG 66. All Maps in Attachments 3 to 8 are derived from MapInfo maps whichare also displayed in AMG 66 grid references.

The radio link maps have been examined and the links crossing the wind farmsite and near radio sites have been identified from the ACMA data. There are atotal of 5 point-to-point links: one in the 450 MHz band, three in the 900 MHzband and one in the 7.5 GHz band operated by Victorian State EmergencyService, Vertical Telecoms, Country Fire Authority, Goulburn Valley RegionalWater and Airservices Australia respectively on 3 paths which cross the site. Asummary of the calculated 2nd or 0.6 x 1st Fresnel zone clearances at mid-pathare shown in Tables 1 & 2. The proposed location of the turbines have beenshown in the link maps generated in MapInfo and were used to confirm thatdistances from radio link ray lines and the turbine tower centre lines meet theclearance criteria derived below.

TABLE 1 - MICROWAVE LINK CLEARANCES

PATH ACMASite ID’s

TotalPath Dist.km

FrequencyMHz

Operator *Mid Path 2ndFresnel ZoneDistance m

35744-11920 58.78 7500 Airservices 34.3*Corridor Width is total zone width around radio path where no intrusion of blade tipcan occur = 2 x 2nd Fresnel Distance above

TABLE 2 - VHF/UHF LINK CLEARANCES

PATH ACMASite ID’s

TotalPath Dist.km

FrequencyMHz

Operator *Mid Path 0.6x 1stFresnel ZoneDistance m

300723-11919 58.84 900 VerticalTelecoms

42

302190-11913 53.43 900 CFA 4041841-11916 58.87 400 Vic State

Emergency63

41841-11915 58.89 900 GoulburnValley Water

42

*Corridor Width is total zone width around radio path where no intrusion of blade tipcan occur = 2 x0.6 x 1st Fresnel Clearances above

It was discovered that the coordinates in the ACMA database of CFA site 302190are in error after checking with the CFA and the correct coordinates wereestablished after physical recognition of the site in Google Earth. The linkmapping was rerun with the addition of the corrected site. The links associated

of 36


with the corrected site are shown in green in the MapInfo generated maps ofAttachments 5 & 6 (in addition to the incorrect links in blue).

The calculation of the reflection/scattering zone using the Bacon formula (Ref. 8)requires iteration with increasing values of the distance from the path bore sightat each distance from the terminal until the required C/I value is reached. As therecommended clearance distances above are calculated for the mid path for eachlink (where the clearances are at a maximum) scattering from turbines near aradio site will be low.

6.2 Cellular Mobile Base Stations

The nearest cellular mobile base stations are registered at sites 9001918 and9002541 which are approximately 3.9 and 4.8 km respectively from the nearestturbines on the proposed wind farm site. At these distances it is considered thatthe operation of the turbines will have no significant impact on the cellular mobilecoverage; however, it is recommended that Optus, Vodafone and Telstra beadvised of the wind farm proposal.

6.3 Two-Way Mobile

A number of private and Public Utility mobile bases exist in the area surroundingthe wind farm site. These bases potentially provide cover to mobiles in a 360degree arc from their bases. No significant impact from the wind farm on basecoverage beyond normal mobile operational performance is predicted in view ofthe geographic separation between the base antennas and the turbine structures.Of course, a mobile transceiver unit communicating with a base station when themobile is located within metres of the wind turbine structures (or indeed near anylarge building, silo, tower, etc.) may experience some very local performancechange, however moving a short distance would restore performance to normal.

6.4 CB Radio

CB radios are not individually licensed, the equipment being subject to classlicensing only. Therefore no records of location or operators of CB radios exist,and the channels are shared without any right of protection from interference. Noimpact from the wind farm is predicted except perhaps for very local effects toportable or mobile units in the immediate vicinity of the turbines which could beavoided by a small location change of the unit. Some CB repeater stations arelisted within the 50 km study area however no site is close enough to the windfarm to cause coverage impairment.

6.5 Aviation Services

There are no radar sites listed within the 50 km radius study area surrounding theproposed wind farm. Airservices Australia and Mangalore Airport Pty Ltd haveregistrations for VHF services at Mangalore Airport. Due to adequate separationdistance to turbines of at least 23 km, no impact to these services is predicted. AnAirservices radar installation exists on Mt Macedon which is 68 km from the windfarm and is line-of-site from the turbines under average propagation conditions. Acheck should be made with Airservices on whether this is a Primary Surveillance

of 36


Radar (PSR) and if so whether the wind turbine locations will have any significantimpact on the radar operation.

6.6 Point-to-Multipoint (PMP) Systems

There are a number of PMP systems registered in the 50 km radius from the windfarm study area boundaries. The PMP base stations are registered in the ACMAdata base however the customer/remote ends are generally not registered forPMP systems, so that it is not possible to check if any turbines are in the pathsfrom the base station to the customer ends. These systems operate both in theVHF and UHF frequency bands and are listed in Table 3 below.

TABLE 3 - POINT-TO-MULTIPONT SYSTEMS IN THE AREA

Site/Service Frequency BandMHz

Operator Comment

Mt Wombat 160 Strathbogie Shire VHFVarious 450 Goulburn Water UHFWallan 450 Yarra Valley

WaterUHF

Mt Wombat 450 SPI Electricity UHFMt Hickey 900 Telstra UHF

Given that the base station locations are remote from the proposed wind farm sitethere is a low probability that any path to the remote (subscriber or device) sitewould cross the wind farm. It may however be prudent to advise the operators ofthe PMP Services of the wind farm proposal. There were no PMP registrations inthe microwave frequency bands.

6.7 Radio Sites in Close Proximity to Wind Turbines

No radio sites are located inside the wind farm boundaries and there are 3 siteslocated about 3 to 4 km from the nearest turbine and are not close enough to beconsidered from a buffer zone point of view. There are no TV/Radio broadcastingor emergency services paging facilities on the near sites which would requireconsideration of buffer zones.

6.8 Met Bureau Radar and Other Services

No registrations for any Meteorology Bureau radar were found in the area. Anaeronautical service registration exists at Pretty Sally which would not beimpacted by the wind farm.

7. EMI EFFECTS OF WIND TURBINES

The following is an extract from Ref. 1:

"It is well known that any large structure, whether stationary or moving, in thevicinity of a receiver or transmitter of electromagnetic signals may interfere withthose signals and degrade the performance of the transmitter/receiver system.Under certain conditions, the rotor blades of an operating wind turbine may

of 36


passively reflect a transmitted signal, so that both the transmitted signal and adelayed interference signal (varying periodically at the blade passage frequency)may exist simultaneously in a zone near the turbine. The nature and amount ofelectromagnetic interference (EMI) in this zone depend on a number ofparameters, including location of the wind turbine relative to the transmitter andreceiver, type of wind turbine, physical and electrical characteristics of the rotorblades, signal frequency and modulation scheme, receiver antennacharacteristics, and the radio wave propagation in the local atmosphere. Otherwind turbine components which have been considered to be potential causes ofEMI are towers and electrical systems. However, neither of these has been foundto be a significant source of interference. Thus, moving blades are thecomponents of most importance in determining EMI levels.

Television Interference from wind turbines is characterised by video distortion thatgenerally occurs in the form of a jittering of the picture that is synchronised withthe blade passage frequency.

Effects on FM broadcast reception have been observed only in laboratorysimulations."

Point-to-point links in microwave and lower frequency bands will be affected onlyif the turbine tower or turbine clearance to the line of site path to the other end ofthe link is within the second Fresnel zone which is dependent on the operatingfrequency of the link, the distance of the tower/turbine from the link antenna andthe total link distance. D. F. Bacon (Ref. 8) proposes 3 potential degradationmechanisms - near field effects, diffraction and reflection or scattering. Thereflection or scattering treatment in the reference suggests greater clearancerequirements at positions close to the link terminals than the usually applied toFresnel Zone clearance for certain links with low antenna gain. This has beentaken into account for this study.

8. DISCUSSION OF OVERSEAS EXPERIENCE

Observations and studies have been carried out for a number of years in both theUSA and the UK on the effects of wind turbines on TV and otherradiocommunication services. In 1976 the US Energy Research andDevelopment Administration (ERDA) funded the RadLab at the University ofMichigan for investigations into these effects and this continued for 7 years. Ref.1 summarises the results of theoretical and field measurements.

The BBC's Research Department in the UK has also investigated this subject insome depth, and in 1983 a report was issued (Ref. 2). Another Report (Ref. 3)was issued in 1992 after the Research Department had carried out observationsfrom test transmissions at existing wind farms in Denmark in 1991.

In 1992 the ITU issued a Recommendation (Ref. 4) on the assessment ofimpairment caused to television reception by a wind turbine.

Ref. 5 summarises the results of model measurements of the level of interferencesignals scattered by turbine blades and the supporting tower and confirms someof the backscatter estimates calculated in Ref. 4.

of 36


Metal blades were used for some earlier turbines unlike the modern ones wherecomposite material - fibre glass, carbon fibre, plastics are used. In some casesmetal exists in the composite material blades for strength reinforcing or forlightning protection. Some references, e.g. Ref. 1, indicate that the compositeblades may have a reduced interference potential although metal inclusions in theblades could increase the scattering efficiency to that of metallic blades.

It is also indicated in Ref 7 that due to variable wind speeds and direction, theresulting changes to turbine blade pitch and turbine facing direction will modifyany interference levels at a given location in the service area i.e. interferenceeffects would be time variant.

In relation to domestic TV reception in close proximity to wind turbines Ref. 7issued by the BBC/Ofcom in the UK states that “In practice rarely does the toweror nacelle have any effect on reception; the impact on reception is solely onaccount of the rotating turbine blades. As the blades are moving objects, in termsof both their rotational speed and orientation, their effect is variable and hard topredict. When the combined effects of a number of turbines that comprise a windfarm are considered, the result is considerably more difficult to predict.Ref. 11 a report issued in 2009 summarises measurements taken around anoperating wind farm in the UK in relation to the impact on radio links. A mainconclusion is “The only mechanism observed, by which wind farms may degraderadio link performance, is that of reflection and scattering from the turbinestructure and blades. Such reflected energy may combine destructively with thedirect path signal to give deep nulls in the received power level. The impact ofsuch interference is primarily determined by the relative discrimination affordedby the transmitter and receiver aerials. Furthermore, if the wanted path isobstructed (e.g. due to local clutter or intervening terrain) while the turbine is lineof sight to both terminals, the impact of such interference will be increased”.

Recently in May 2011 a new recommendation BT.1893 (Ref. 12) on impairmentcaused to digital television was issued by the ITU following on from the issue ofan ITU Report BT.2142 (Ref. 13) in 2009-2010 which provides an extensiveanalysis of the effect of the scattering of digital television signals from windturbines. These new documents indicate that back scatter of signals is higherthan forward scatter and that static reflections from the tower itself in addition tothe blade scatter are significant. These conclusions appear to differ from theearlier ITU report conclusions which were focused on analogue television. TheITU recommendation BT.1893 in Annex 1 presents a simplified model ofimpairment caused to television reception by a wind turbine. It however requiresmeasurement or prediction of TV signal levels at the centre of the turbine rotorand at the house locations as well as calculation of a scattering coefficient basedon the blade area, signal wavelength and distance from the turbine to the houselocation.

From a study of the above references and others, the following generalconclusions are drawn:

(a) No turbine interference effects are expected to MF radio reception.

(b) There is a very low probability of perceptible interference to FM radioreception.

of 36


(c) Some interference may be experienced to analogue TV services andparticularly where the path to the TV transmitter for a given receiver location isthrough the wind turbine blades or where there is a partly obstructed path to thetransmitter and there is a clear path to a turbine. These effects may be restrictedup to a distance of about 3 km from a single wind turbine in forward scatterdirections (receiver on opposite side of the wind farm to the TV station).Backscatter may occur up to 0.5 km or so however as TV receiving antennashave a reasonable signal rejection to the rear it is unlikely that TV reception atdwellings in the back scatter zone will experience any impairment.

(d) Digital TV services are unlikely to suffer degraded picture quality, e. g.ghosting, where signals have a margin above threshold levels, however areduction in service area could occur due to time varying reflected signals.

9. CHERRY TREE WIND FARM SITUATION

From overseas and Australian experience and the topography of the area:

9.1 No interference from the wind farm is expected to the MF and FM soundbroadcasting services in the area.

9.2 From Ref. 6 reflections of TV transmissions from typical transmitting sitesby the turbine blades indicate that some possibility of analogue TV picturedegradation exists at times for dwellings located such that wind turbines wouldpotentially exist within a +/- 20 degree sector from the TV antenna nominaldirection of reception, and up to about 3 km from the turbines. It is also difficult toestimate the additive effects of a number of turbines distributed over somedistance and on the effect of the undulating terrain on the ratio of the reflectedsignal to the main wanted TV signal.

9.3 Due to the undulating terrain around the wind farm and the resultant needto obtain reception from alternative TV transmitting station directions it is difficultto predict where interference may occur. In general, dwellings to the south andeast of the wind farm and close to turbines would have had an increased risk ofhaving some interference to analogue TV signals (which have now ceased) fromtransmission from Victorian Regional stations in the area.

9.4 As indicated above, digital television is not subject to ghosting degradationin high signal strength areas, however some reduction of service area couldresult from reflected unwanted signals at the limits of the service area. There maybe some isolated areas which are shadowed by local hills resulting in reducedsignal levels; however, such effects are unlikely, but are also difficult tocategorically exclude as a possibility.

9.5 There are at least 4 medium/low power TV rebroadcast stations in thearea. These stations generally retransmit the TV signals transmitted from a mainstation or are satellite fed for local area fill-in coverage. The off air receptionsituations are not shown on the ACMA database as licensed links, and thereforedo not appear on the link mapping. Rebroadcast stations for Alexandra, Seymour,and Broadford possibly have some digital programmes received off air from eitherGoulburn Valley or Bendigo main stations. If their input signals passed near to, or

of 36


through, the wind farm, some interference to input signals and therefore to the TVservice areas of each station could occur. However a check of the three pathsfrom both stations to the retransmission sites indicates that they do not cross orcome close to the wind farm boundaries. Any disturbance to the input to these TVrebroadcast stations as a result of the wind farm is therefore very unlikely. Insome cases individual services e.g. the SBS are few via a satellite link with littleprobability of obstruction from wind turbines. In the case of the Yearetransmission station indications are that it may receive some channels from theSeymour station (based on the situation previously existing for analogue TV). Thepath from the Seymour station to the Yea station passes to the south of the windfarm. There is some possibility of interference to the input signal to the Yeastation however with digital transmission it may not be an issue.

9.6 For satellite pay TV services in the area of the wind farm no interferenceto these services is likely to occur unless the required pointing of their dishantennas to the serving satellite is also in line with a turbine.

9.7 The ACMA RADCOM database has been studied for services within atleast 50 km of the wind farm to determine if any point to point services will havetheir paths obstructed by the wind turbine blades or the supporting towers. Mapsderived from the ACMA database showing radio sites and links in the generalarea surrounding the site are shown in Attachments 3 & 4. One microwave radiolink path and four UHF radio link paths have been identified as crossing theproposed wind farm site. These are shown in zoomed map views in Attachments5, 6, 7 & 8. Attachment 14 provides sample calculations of the clearance requiredto achieve 2nd Fresnel clearance near the turbines for the microwave systemsand 0.6 x 1ST Fresnel zone clearance in the VHF/UHF cases. In Attachment 15these Fresnel zone distances have been calculated at the mid-point of the linkpath, where they are at a maximum, to provide some margin for error of radiotower grid references in the ACMA database. Three link paths currently do nothave sufficient horizontal clearance. To determine if any of the radio path raylines potentially have sufficient vertical clearance over the top of the turbines,representative vertical path profiles were generated from digital elevation modeldata and are shown in Attachments 10 to 13. These show the terrain profileincluding earth curvature for effective earth radius factor of K = 0.6 along theradio ray lines. K=0.6 is a conservative figure representing radio propagationconditions for a small percentage of the time which is modeled as a greater earthbulge. Representative wind turbine structures are superimposed on these terrainprofiles representing the turbine tower height plus blade length (159 metres) andhave been positioned in representative locations for the nearest turbines to theradio paths. The vertical path profiles of links paths shown in Attachments 10 to13 indicate that the microwave link and 3 of the UHF links may have adequateturbine blade tip clearance. Horizontal spacing of the distances shown in thetables of Attachment 15 are however required to be maintained for the CFA UHFlink which does not have turbine blade tip clearance.

9.8 The closest Airservices Australia radio facility at Mangalore Airport issufficiently separated from turbines and is of the type not to be interfered with byturbines as they are for ground to air communication. Confirmation fromAirservices should be obtained that Radar coverage from Mt Macedon will not beimpaired by the wind turbines

of 36


9.9 As shown in table 3 above, VHF and UHF point-to-multipoint (PMP)system registrations exist in the study area although base stations are not veryclose to the proposed wind farm. The operators of this system may be in aposition to assess if there are any impacts to their individual customers’ servicesor remote points. It is recommended that these organisations be correspondedwith to obtain their views of any potential turbine interference potential to theircustomers.

9.10 As there are no radio or broadcasting facility sites in or close to the windfarm within about 4 km, no buffer zones are required to be specified. Normally arecommended buffer zone for the location of any wind turbine is a circle of radius800 metres around a radio tower location.

10. AVOIDANCE OF INTERFERENCE DURING CONSTRUCTION

10.1 There is a potential to cause interference to the radio links duringconstruction of the wind farm from the use of large construction cranes. Thesecould be erected in locations where the crane tower or boom could traverseacross the line-of-sight paths of radio links.

10.2 It is understood however that the cranes will normally work within the rotordiameter so that no special procedures will be necessary as the location ofturbine towers allows for the operational rotor diameter in the clearancesspecified. If any movement of cranes is contemplated without dismantling,avoidance of the operating radio link paths and Fresnel clearances will beneeded.

11. METEOROLOGICAL MAST LOCATIONS

The locations of temporary and permanent meteorological masts approx. 80metres high will potentially need to avoid the CFA radio link ray line crossing thesite with the calculated horizontal clearance in Table 2 being maintained. Therewill be sufficient vertical clearance of 80 metre masts to the ray lines of all otherradio links to not require any minimum horizontal clearances being specified.

12. POWER INFRASTRUCTURE ELECTRIC AND MAGNETIC FIELDS

The power generated by the wind turbines will be exported to the transmissiongrid via purpose built substation/s and high voltage transmission lines usingconventional designs to meet standards applying to the State network at large.Substation/s will be designed and sited to reduce the electric and magnetic fieldsto acceptable levels at the boundary fence. The internal wind farm reticulation willemploy underground cables or overhead transmission lines of up to 33 kV involtage. The main transmission lines from the wind farm substation to the grid willemploy higher HV overhead lines. All transmission lines will be built tospecifications consistent with the HV lines throughout the State network. Theheight of the lines and the easement width will be in accordance with SP Ausnetrecommendations which will ensure magnetic and electric fields will be withinacceptable limits for human exposure and electromagnetic interference levels atdwellings in the area and for accessible public access areas. For a 275 KV linethe usual easement width is 50 metres. Depending on the number of circuitscarried, the lower lines would typically be suspended from poles up to 30 metres

of 36


above ground level with human exposure limits met at ground level. HV powerlines and substations are required to meet Australian Standard AS/NZS 2344:1997 Amendment 1:2007 Limits for EMI, which protects broadcasting andradiocommunications reception from unacceptable interference. The overheadpower lines are not expected to obstruct any radiocommunications systems whichcross the wind farm in view of their relative low height (30 m) above ground. Thedistance of approx. 4 km to the nearest radiocommunications site will also ensurethat EMI from the power infrastructure will have no impact on radio systemreceivers at that site.

13. FORTUITOUS RECEPTION OF BROADCAST SIGNALS

On some previous projects Responsible Authorities have imposed conditionssuch as:

"if the qualitative survey establishes any detrimental increase in interference toreception or transmission measures must be taken to mitigate the interference toreturn the affected reception or transmission to pre-construction quality”(Waubra Vic Planning Permit No PL-SP/05/0150).

This raises two issues primarily for analogue TV reception, the first being thecriteria for interference assessment and the second being the protection ofreception of some services outside their designed coverage area - termedfortuitous reception. For analogue television reception, which is the mostvulnerable service for turbine interference, it is proposed to use the ITU grade 4,of a 5 grade impairment scale as the limit of acceptance, which is described as"perceptible but not annoying". On the second point, the ACMA's attitude toprotection of reception outside designed service areas is understood to be thatthe reception is fortuitous and will not be protected. They will therefore plan forreuse of frequencies for new stations which in future may impair reception inareas where it is currently acceptable or useable, often for at least part of thetime.

This is, of course, difficult for individuals to accept who, due to their particularlocation, cannot receive an acceptable service from their planned station. Othersmay use distant stations to avail themselves of diverse programs. It is notreasonable to attempt to protect these services which are likely to be of low signallevel and may vary in quality of reception depending on the time of day, weatherpatterns and season. It is therefore not recommended to mitigate any receptionwhich may be impacted by turbine effects where the receivers are clearly outsidethe ACMA planned coverage area for the particular service being received.

14. MITIGATION TECHNIQUES

As indicated above, analogue TV broadcast has been switched off for theRegional Victorian stations in the area. Even with any out-of-area analogue TVreception at a few residences (e. g. from Melbourne stations) any mitigation ofinterference will involve digital television reception as all analogue TV broadcastin Australia will be switched off by December 2013.

of 36


For individuals who experience any degraded FM (unlikely) or TV broadcastingservice due to identified interference from the wind farm, possible techniques toreduce the interference to acceptable limits include:

1. Replacement of receiving antenna system with a higher gain more directivemodel,

2. Reposition antenna in height or horizontally on the dwelling,

3. Install an antenna elsewhere on the property and cable to dwelling,

4. Change the orientation of antennas to receive an alternative station if available,

5. Provision of an alternative satellite service e.g. the proposed Viewer AccessSatellite Television (VAST) (Ref. 10) or Austar Pay TV Service.

6. In certain circumstances, consideration could be given to the installation of aTV or FM repeater station to provide service to groups of residents in a shadowzone. However this is only likely to be justified for higher density populationareas.

Potential point-to-point system and mobile base coverage conflict is not expectedif turbines are located with recommended clearance zones from radio sites orpoint-to-point ray lines. There are 3 identified radio links passing to the west ofthe site with significant margin.

Any minor effects to MF broadcasting would occur within 10's of metres of theturbines only and with a buffer zone of at least 500m to any dwelling, nocorrective action will be required.

15. CONCLUSIONS

Interference to MF and FM sound broadcasting is not expected.

Potential conflicts between 4 of the 5 point-to-point radio system paths identifiedabove and the proposed wind turbines will not require any horizontal clearance tobe maintained between link ray line and turbines as there is sufficient verticalclearance. For the CFA link horizontal clearance proposed in Attachment 15 willneed to be maintained as there is no vertical clearance. The current turbinecoordinates for the closest WTG 08 shown in Attachment 1 provides sufficientclearance to this link. These conclusions are based on the current wind turbinelocations with grid references shown in Attachment 1. However, if significantrevision of wind turbine locations occur further checks would be required toensure either horizontal or vertical clearances to the link ray lines are maintained.There are no radio sites close enough to the wind turbines to require buffer zonesto be specified.

Mobile radio and other radiocommunication services in the area are not expectedto be significantly impacted by the wind farm or its operation.

Analogue TV reception at dwellings within about 5 km of the proposed windturbines and with antennas having turbines located with +/- 20 degrees angle of

of 36


their reception direction will have some probability of noticeable effects at times.Any degradation of reception experienced may be time variant depending onwind direction and speed. However, as analogue TV transmission is scheduled toend in 2013, this will not be an ongoing issue.

Digital TV is not susceptible to visible ghosting degradation where the signal levelis above a minimum threshold. The area surrounding the wind farm is expected tobe a medium to high signal area. However, there may be a few individual houseslocated in shadow areas where other mitigating techniques may need to beapplied.

Should any confirmed analogue interference (only if Melbourne reception used)problems occur during the wind farm construction period where TV receivingantenna system improvements are unsuccessful, the use of a set top box withreception of the available digital channels may be the best solution. ExistingDigital TV services are expect to provide unimpaired picture to any houses nearthe turbines which may have experienced picture quality problems as a result ofghosting on analogue TV services as long as the signal levels have a marginabove a threshold level.

Alternatively a satellite service could be considered if digital TV reception isunsatisfactory in individual cases. In particular, the proposed Viewer AccessSatellite Television (VAST) Service announced by the Government recentlywould be available to provide a full complement of digital channels including aregional news channel.

Overseas experience indicates that EMI produced by the wind farm generatorsand controls is not a problem with reputable world class wind turbinemanufacturers and therefore no electrical noise measurements from the electricalgenerators are warranted.

It is recommended that operators of point-to-point radio systems that are near thewind farm site, point-to-multipoint operators identified in section 6.6 above, theCommercial Television Station operators in the area, Broadcast Australia for theABC and SBS and Airservices Australia be advised of the proposed wind farmproject to enable these organisations to confirm that there are no potentialinterference issues seen to be relevant to their operations.

REFERENCES

1. David E Spera, Wind Turbine Technology, Chapter 9 ASME Press 1994

2. J.L. Eaton, R.I. Black, G.H. Taylor, Interference to Television Reception fromLarge Wind Turbines, BBC Research Department Report 1983/2

3 D.T. Wright, Effects of Wind Turbines on UHF Television Reception, Field Testsin Denmark Nov 1991, BBC Research Department Report 1992/7

4. ITU, ITU-R Recommendation BT805 Assessment of Impairment Caused toTelevision Reception by a Wind Turbine 1992

of 36


5. C. Salema, C. Fernandes, L. Fauro, TV Interference from Wind TurbinesConferencia de Telecomunicacoes April 2001 Portugal

6. ITU, ITU-R, Recommendation BT 419-3 Directivity and PolarisationDiscrimination of Antennas in the Reception of Television Broadcasting 1992

7. BBC, Ofcom, UK, The Impact of Large Buildings and Structures (IncludingWind Farms) on Terrestrial Television Reception 26 Oct 2009

8. D. F. Bacon, A Proposed Method for Establishing an Exclusion Zone around aTerrestrial Fixed Link outside of which a Wind Turbine will cause NegligibleDegradation of the Radio Link, Ofcom UK Report Ver 1.1, 28 Oct 2002

9. Environment Protection and Heritage Council (EPHC) National Wind FarmDevelopment Guidelines (Draft) - July 2010.

10. Media Release, Senator the Hon Stephen Conroy, “Digital SwitchoverLegislation Passed” 25th June 2010

11. B S Randhawa (ERA), R Rudd (Aegis), RF Measurement Assessment ofPotential Wind Farm Interference to Fixed Links and Scanning Telemetry DevicesERA Report No 2008 – 0568 (issue 3) March 2009

12. ITU, ITU-R, Recommendation BT.1893 Assessment of Impairment Caused toDigital Television Reception by a Wind Turbine May 2011

13. ITU, ITU-R, Report BT.2142-1 The Effect of the Scattering of DigitalTelevision Signals from a Wind Turbine October 2010

of 36


ATTACHMENT 1 –CHERRY TREE WIND FARM TURBINE COORDINATES

Layout REV N 16xVESTAS V112 2012.04.03 inc. WTG 08 shift

GDA 94 Zone 55

Turbine X Y

WT09 345517 5892182

WT07 347081 5892580

WT06 346834 5892599

WT05 346579 5892639

WT11 345019 5892053

WT12 345186 5891362

WT04 346317 5892775

WT03 346068 5893036

WT08 346010 5892384

WT02 345762 5893250

WT13 344782 5892039

WT01 345477 5893385

WT10 345251 5892059

WT15 344335 5891945

WT14 344561 5891994

WT16 344661 5891298

These coordinates include variations due to Fauna & Flora issues and to a WTG08 relocation to avoid the CFA radio link path.

of 36


ATTACHMENT 2 - TELEVISION STATIONS & CHANNELS – CHERRYTREE WIND FARM AREA

TransmitterLocation/service

Operator AnalogChannels

DigitalChannels

Comment

Mt Major/Goulburn Valley

SBS 36H UHF

ABC 37H UHF

VTV 9V VHF

GLV 42H UHF

AMV 45H UHF

Mt Alexander/Bendigo

SBS 28H UHF

ABC 48H UHF

VTV 54H UHF

BCV 51H UHF

AMV 31H UHF

Meadows HillSeymour

SBS 66H UHF

ABC 53H UHF

VTV 57H UHF

GLV 63H UHF

AMV 60H UHF

YarckAlexandra

SBS 67V UHF

ABC 60V UHF

VTV 63V UHF

GLV 61V UHF

AMV 64V UHF

of 36


Comment

Constitution HillYea

SBS 37H UHF

ABC 34H UHF

VTV 40H UHF

GLV 43H UHF

AMV 46H UHF

Source: ACMA Radio and Television Broadcasting Stations (Internet Edition, July 2011)

of 36


ATTACHMENT 3 - Radio Link Map 40- 999 MHz Frequencies

kilometres

0 12.5 25

5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N

5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N

5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N

5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N

5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N

11,594

11,913

11,914

12,005

12,007

34,526

35,744

36,002

36,217

36,223

36,268

37,479

37,889

37,912

37,913

38,001

38,125

38,126

38,609

38,769

38,837

39,244

39,278

40,660

40,787

41,617

42,163

42,199

42,244

42,245

42,604

42,710

42,872

43,33843,420

43,672

43,675

43,676

43,677

43,849

43,884

43,885

43,917

45,853

45,866

45,92345,949

46,020

46,023

46,024

46,025

46,039

46,043

46,120

46,526

47,119

49,687

49,932

50,544

53,012

53,698

54,742

100,368

130,384

131,862

131,919

133,116

133,231

134,839

135,037

136,875

137,861

138,183

138,977

139,056

139,803

204,889

300,270300,680

300,744

300,789

301,492

301,749

302,008

302,043

302,615

303,487

304,547

304,663

305,046

305,357

305,483

9,001,904

9,001,907

9,002,011

9,002,317

9,002,563

9,009,920

9,010,729

9,900,286

9,914,551

Postal: P.O. Box 3213, BELCONNEN ACT 2617Telephone: 02 6253 2555Facsimile: 02 6253 2800

TITLE:

40-999 MHz AssignmentsAs Extracted from RRL Database

FILENAME:Cherry Tree 40-999 MHz

PROJECT:Cherry Tree

DRWG NO:1 of 2

DATE:13/9/2011

SCALE:N/A

BY:SEA

of 36


ATTACHMENT 4 - Radio Link Map above 1000 MHz Frequencies

kilometres

0 12.5 25

5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N5875000°N

5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N5925000°N

5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N5900000°N

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

400000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

375000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

350000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

325000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

300000°E

5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N5850000°N

5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N5950000°N

5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N5825000°N

11,597

11,914

12,006

12,007

34,526

34,647

35,744

36,015

36,217

36,223

36,269

36,765

36,793

36,894

37,479

37,889

37,912

37,913

38,001

38,126

38,270

38,608

38,609

38,769

38,837

40,660

42,507

42,710

50,544

50,591

50,965

51,16054,742

101,989

130,383

130,384

131,710

134,839

134,904

300,411

300,414

300,744

301,075

301,106

301,766

301,819

302,043

302,725

303,759

304,298

304,547

304,582

305,225

305,243

305,248

305,294

305,334

305,348

305,438

305,442

305,458

305,483

305,686

305,687

305,740

502,392

9,004,515

9,900,286

Postal: P.O. Box 3213, BELCONNEN ACT 2617Telephone: 02 6253 2555Facsimile: 02 6253 2800

TITLE:

Above 1 GHz AssignmentsAs Extracted from RRL Database

FILENAME:Cherry Tree Above 1GHz

PROJECT:Cherry Tree

DRWG NO:2 of 2

DATE:13/9/2011

SCALE:N/A

BY:SEA

of 36

Cherry Tree Wind Farm Electromagnetic Interference Assessment – Possible Impacts on Broadcasting & Radiocommunications Services

ATTACHMENT 5 – Map of VHF/UHF Radio Link Paths near Wind Turbines

Note: minor revised wind turbine locations contained in Attachment 1 are not shown

Corrected CFA radio link path shown in green

WT09

WT07WT06WT05

WT11

WT12

WT04

WT03

WT08

WT02

WT13

WT01

WT10

WT15 WT14

WT16

of 36


ATTACHMENT 6 – Map of VHF/UHF Radio Link Path near Wind Turbines – Detail


Corrected CFA radio link path shown in green

WT09

WT07WT06

WT05

WT11

WT04

WT03

WT08

WT13WT10

WT15WT14

of 36


ATTACHMENT 7 – Map of Microwave Radio Link Paths near Wind Turbines


WT09

WT07WT06WT05

WT11

WT12

WT04

WT03

WT08

WT02

WT13

WT01

WT10

WT15 WT14

WT16

of 36


ATTACHMENT 8 – Map of Microwave Radio Link Paths near Wind Turbines – Detail


WT12

WT16

of 36


ATTACHMENT 9 – PATH PROFILE AIRSERVICES MICROWAVE LINKRed line – radio path ,Blue lines – 1st and 2nd Fresnel zonesRepresentative turbine shown with 159 m blade tip height

A ir S e rv ic e s M ic ro w a v e L in k

In d ic a t iv e T u rb in e s S h o w n

F e b 1 9 1 2

L a w re n c e D e rr ic k & A s s o c ia te s

3 5 7 4 4

L a t itu d e 3 7 1 0 3 5 .7 5 SL o n g itu d e 1 4 5 0 9 0 9 .9 0 EA z im u th 5 2 .1 5 °E le v a t io n 8 0 7 m A S LA n te n n a C L 1 0 .0 m A G L

1 1 9 2 0

L a t itu d e 3 6 5 1 0 1 .4 6 SL o n g itu d e 1 4 5 4 0 2 3 .4 1 EA z im u th 2 3 1 .8 3 °E le v a t io n 7 8 8 m A S LA n te n n a C L 1 0 .0 m A G L

F re q u e n c y (M H z ) = 7 5 0 0 .0K = 0 .6 0

F n = 1 .0 0 , 2 .0 0

Ele

va

tio

n(m

)

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

P a th le n g th (5 8 .7 8 k m )0

51 0

1 52 0 2 5 3 0 3 5 4 0

4 55 0

5 5

of 36


ATTACHMENT 10 - PATH PROFILE VERTICAL TELECOMS UHF LINKRed line – radio path ,Blue lines – – 1st and 0.6x 1st Fresnel zonesRepresentative turbine shown with 159 m blade tip height

V e r t ic a l T e le c o m s U H F L in k


F e b 1 9 1 2

L a w re n c e D e r r ic k & A s s o c ia te s

3 0 0 7 2 3

L a t i tu d e 3 7 1 0 3 6 .5 6 SL o n g itu d e 1 4 5 0 9 0 9 .4 7 EA z im u th 5 2 .1 1 °E le v a t io n 8 0 6 m A S LA n te n n a C L 5 .0 m A G L

1 1 9 1 9

L a t i tu d e 3 6 5 1 0 0 .2 0 SL o n g itu d e 1 4 5 4 0 2 4 .0 8 EA z im u th 2 3 1 .8 0 °E le v a t io n 7 9 2 m A S LA n te n n a C L 5 .0 m A G L

F re q u e n c y (M H z ) = 9 0 0 .0K = 0 .6 0

% F 1 = 6 0 .0 0 , 1 0 0 .0 0

Ele

vatio

n(m

)

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

P a th le n g th (5 8 .8 4 k m )0

51 0

1 52 0 2 5 3 0 3 5 4 0

4 55 0

5 5

of 36


ATTACHMENT 11 – PATH PROFILE VIC. COUNTRY FIRE AUTHORITY UHF LINKRed line – radio path, Blue lines – 1st and 0.6x 1st Fresnel zonesRepresentative turbine shown with 159 m blade tip height

C F A U H F L in k

In d ica tive T u rb in e s S h o w n

F e b 1 9 1 2

L a w re n c e D e rrick & A ss o c ia te s

3 0 2 1 9 0

L a titu d e 3 7 0 2 3 6 .4 4 SL o n g itu d e 1 4 4 4 9 1 1 .2 8 EA z im u th 9 9 .3 8 °E le va tio n 5 6 5 m A S LA n te n n a C L 4 .0 m A G L

1 1 9 1 3

L a titu d e 3 7 0 7 1 3 .7 2 SL o n g itu d e 1 4 5 2 4 4 6 .7 5 EA z im u th 2 7 9 .0 3 °E le va tio n 6 4 4 m A S LA n te n n a C L 5 .0 m A G L

F re q u e n cy (M H z ) = 9 0 0 .0K = 1 .3 3

% F 1 = 6 0 .0 0 , 1 0 0 .0 0

Ele

vatio

n(m

)

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

P a th le n g th (5 3 .4 3 k m )0

51 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5

5 0

of 36


ATTACHMENT 12 – PATH PROFILE VIC. GOULBURN VALLEY WATER UHF LINKRed line – radio path, Blue lines – 1st and 0.6x 1st Fresnel zonesRepresentative turbine shown with 159 m blade tip height

G o u lb u rn V a lle y R e g io n W a te r U H F L in k


F e b 1 9 1 2

L a w re n c e D e r r ic k & A s s o c ia te s

4 1 8 4 1

L a t itu d e 3 7 1 0 3 6 .0 7 SL o n g itu d e 1 4 5 0 9 0 9 .4 8 EA z im u th 5 2 .0 5 °E le v a t io n 8 0 8 m A S LA n te n n a C L 5 .0 m A G L

1 1 9 1 5

L a t itu d e 3 6 5 0 5 7 .3 1 SL o n g itu d e 1 4 5 4 0 2 3 .8 9 EA z im u th 2 3 1 .7 4 °E le v a t io n 7 8 8 m A S LA n te n n a C L 5 .0 m A G L

F re q u e n c y (M H z ) = 9 0 0 .0K = 0 .6 0

% F 1 = 6 0 .0 0 , 1 0 0 .0 0

Ele

va

tio

n(m

)

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

P a th le n g th (5 8 .8 9 k m )0

51 0

1 52 0 2 5 3 0 3 5 4 0

4 55 0

5 5

of 36


ATTACHMENT 13 – PATH PROFILE VIC. STATE EMERGENCY UHF LINKRed line – radio path, Blue lines – 1st and 0.6x 1st Fresnel zonesRepresentative turbine shown with 159 m blade tip height

V ic S t a te E m e r g e n c y U H F L in k

In d ic a t iv e T u r b in e s S h o w n

F e b 1 9 1 2

L a w r e n c e D e r r ic k & A s s o c ia te s

4 1 8 4 1

L a t i t u d e 3 7 1 0 3 6 .0 7 SL o n g i t u d e 1 4 5 0 9 0 9 .4 8 EA z im u t h 5 2 . 0 5 °E le v a t io n 8 0 8 m A S LA n t e n n a C L 5 . 0 m A G L

1 1 9 1 6

L a t i t u d e 3 6 5 0 5 7 .5 3 SL o n g i tu d e 1 4 5 4 0 2 3 . 4 4 EA z im u th 2 3 1 .7 4 °E le v a t io n 7 8 6 m A S LA n te n n a C L 5 .0 m A G L

F r e q u e n c y ( M H z ) = 4 0 0 . 0K = 0 .6 0

% F 1 = 6 0 .0 0 , 1 0 0 .0 0

Ele

vation

(m)

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

P a th le n g th ( 5 8 .8 7 k m )0

51 0

1 52 0 2 5 3 0 3 5 4 0

4 55 0

5 5

of 36


ATTACHMENT 14 – RADIO LINK DATA AND CLEARANCES

In the event of a microwave point to point system passing near a turbine therecommended clearance from link ray line to turbine blade tip is the Second Fresnelzone radius calculated using the following formula:

Ymin = )2/11(12 DDD (Ref. 1 )

Example Only

1. Site 1 ID 204434 to Site 2 ID 9001068

Operator: OptusFrequency Band 15000 MHzCalculated Path Length : 17.85 kmClearance to WTG at 3.7 km from near site.2nd Fresnel Clearance D1

D1 = SQRT(2 x λ x d1 x (1 – d1/d2)) =SQRT( 2x (300/15000) x 3700(1- 3.7/17.85))= 10.83 metres

The required clearance from the ray line to a tower centreline is 50 + 10.83 = 60.83metres (at 3.7 metres from the microwave tower)

For a VHF/UHF point to point system the recommended clearance from the link rayline to turbine blade tip can be relaxed to 0.6 X Ist Fresnel Zone clearance as there isless disturbance at the lower frequencies due to blade movements or obstructionsgenerally.

Example only

1. Site 1 ID 10712 to Site 2 ID 10652

Ymin = 0.6 )2/11(1 DDD

Operator: NSW FireFrequency Band 450 MHzCalculated Path Length: 38.3 kmClearance at mid path0.6 x 1st Fresnel Clearance D1

D1 = 0.6*SQRT (λ x d1 x (1 – d1/d2)) = 0.6*SQRT ((300/450) x 19150(1-19.15/38.3))= 47.94 metres

The required clearance from the ray line to a tower centreline is 50 + 47.94 = 97.94metres at mid path (19.15 km from either end of link path.)

of 36


ATTACHMENT 15 - SUMMARY OF RADIO LINK CLEARANCE REQUIREMENTS

TABLE A HORIZONTAL CLEARANCE ZONES REQUIRED

PathACMA SITE ID’s

Operator Coords Site A GDA 94Zone 55

Coords Site B GDA 94Zone 55

*Total Clearance ZoneWidth metres**

35744-11920 Airservices. E336012 N5883939 E381710 N5920901 188300723-11919 Vertical Telecoms E336002 N5883914 E381726 N5920940 203302190-11913 CFA E306014 N5897469^ E359012 N5890584 199

41841-11916Vic EmergencyServices

E336002 N5883914 E381709 N5921022 245

41841-11915Goulburn ValleyWater

E336002 N5883914 E381720 N5921029 203

*Total clearance zone width is the corridor centred on radio path ray line outside which the wind turbine tower centre lines must be located. Arotor diameter of 119 metres is assumed.** As 4 ray lines appear to pass over the tip of the turbine blades these horizontal clearances may not be necessary except for the CFA link.^Corrected ACMA coords. after discussion with the CFA.

TABLE B SUMMARY OF HORIZONTAL AND VERTICAL CLEARANCES

Path Hor.ClearanceRequired m

Clearance to TowerCentre Required m

59 m blades

Est. Current Hor.Clearance Near

Turbines m

Hor ClearanceYes/No

Vert. ClearanceYes/No

37744-11920 34.3 93.3 WT12 – 2WT06 - 72

NoNo

YesYes

300723-11919 42 101 WT12 - 8 No Yes302190-11913 40 99 WT08 - 110˜ Yes No41841-11916 63 122 WT12 - 16 No Yes41841-11915 42 101 WT12 - 17 No Yes

˜ for corrected coords. for site 302190 and revised location of WTG 08.

of 36


ATTACHMENT 16- GLOSSARY OF TECHNICAL TERMS

VHF Very High FrequencyUHF Ultra High frequencyEMI Electromagnetic InterferenceVHF Channels TV Channels 0 to 12 (45 - 230 Mhz)UHF Channels TV Channels 28 - 46 (526 - 820 Mhz)Band 111 VHF TV Channels 5A - 12First Fresnel Clearance Clearance to obstructions from the ray line on a radio

Path which does not produce any additional lossabove free space loss

FM Frequency ModulationAM Amplitude ModulationMF Medium FrequencyLF Low Frequency (not used for sound broadcasting in

Australia)GSM European Digital Cellular Mobile SystemCDMA Code Division Multiple Access Cellular Mobile

SystemITU International Telecommunications UnionACMA Australian Communications & Media AuthorityCB Radio Citizens Band RadioVOR VHF Omnidirectional Range (short range air

Navigation aid)

CHERRY TREE WIND FARM ELECTROMAGNETIC … · 6. RADIOCOMMUNICATIONS SERVICES 7. EMI EFFECTS OF WIND...

Documents

Transcript of CHERRY TREE WIND FARM ELECTROMAGNETIC … · 6. RADIOCOMMUNICATIONS SERVICES 7. EMI EFFECTS OF WIND...