mr. geoff carnegie canadian hydro developers, …...november 22, 2007 mr. geoff carnegie canadian...

November 22, 2007 Mr. Geoff Carnegie Canadian Hydro Developers, Inc. 34 Harvard Road Guelph, ON N1G 4V8 Re: Fall 2007 Acoustic Audit Amaranth Transformer Station, Melancthon I Wind Plant Certificate of Approval (Air) Number 2233-6X9NBQ

Dear Mr. Carnegie,

As requested, Howe Gastmeier Chapnik Limited (HGC Engineering) has undertaken an acoustic audit of the Amaranth Transformer Station (TS) associated with the Melancthon I Wind Plant. This audit represents the first of four seasonal audits that will be conducted of the TS noise, as a condition of Certificate of Approval (Air) Number 2233-6X9NBQ issued October 17, 2007 by the Ministry of Environment (MOE).

In summary, the results of the fall 2007 audit are:

1) The data indicate that the noise impact from the TS at the three closest residences was in compliance with the MOE guidelines during the measurement period.

2) It appears that the residents’ concerns may be more related to audibility than to numerical magnitude of the sound level. By itself, audibility does not indicate non-compliance with the MOE Guidelines

3) While no evidence of unusual acoustic phenomena was found on the transformer side of the barrier, and the transformer fans are not an issue, there were periods when the sound levels on the switch side of the acoustic barrier wall were higher than expected. This phenomenon has not

Canadian Hydro Developers, Inc. Fall 2007 Acoustic Audit, Amaranth Transformer Station November 22, 2007

been adequately explored at this time, and will be further addressed during the subsequent acoustic audits.

The acoustic audit is presented in the following sections.

We trust that this information is sufficient for your current needs, and we look forward to working with you in the future.

Howe Gastmeier Chapnik Limited

Nick McCabe, PEng Brian Howe, MEng, PEng


Introduction

The acoustic audit followed the requirements of MOE guideline NPC-233 “Information to be Submitted for Approval of Stationary Sources of Sound”, and also followed the methodology described in a letter prepared by HGC Engineering dated September 17, 2007, agreed to by Dr. Al Lightstone of Valcoustics Canada Ltd. (Valcoustics) and the John Kowalewski of the MOE. This letter, developed with input from the surrounding residents, is attached as Appendix A.

The acoustic audit was based upon a complex series of attended and unattended sound measurements and other data recorded between October 1 and October 9, 2007. These include:

• Attended and automated unattended sound level measurements conducted on the TS site, on both sides of the acoustic barrier;

• Attended and automated unattended sound level measurements conducted at the three principal receptors;

• Electrical power data provided by Canadian Hydro Developers, Inc. (Canadian Hydro) and verified against Independent Electrical System Operator (IESO) data for the same period;

• Meterological data monitored at one of the residences during the measurement period

• The residents’ own logs of observations made during the measurement period.

Throughout this report, the acronym ‘TS’ is used to refer to the transformer station as a whole. However, there are times when the transformer itself is meant, and at these times, the word ‘transformer’ is used.

Background

As part of the C of A application process, Aercoustics Engineering Ltd. (Aercoustics) prepared an Environmental Noise Impact Study for the TS, dated August 21, 2006 along with a supplement dated September 12, 2006. That work addressed the noise impact from the transformer at five neighbouring residential receptors, one of which belongs to the lessor of the land the TS is on. The other four receptors, which are located predominantly to the south, west and northwest of TS, at distances ranging between 360 and 560 m, were predicted by the report to experience sound levels exceeding the nighttime criteria of the MOE when accounting for the tonality of noise produced by the transformer.

A 6.5 metre high Durisol wall has been constructed on three sides of the transformer, although not around the station switchgear or control equipment. Following construction of the acoustic barrier wall, an acoustic evaluation of the transformer was undertaken by HGC Engineering in February of 2007. However, due to inclement weather occurring during the measurements, and restrictions in access to the adjacent private lands at that time, only a limited evaluation was possible. Nonetheless, that report concluded that the measurements made in February 2007 indicated that the TS was operating in compliance with the MOE guideline limits.


Following publication of that evaluation, the MOE and other parties requested additional information. Thus, in preparation for this audit, a protocol document was prepared with input from the local residents, Valcoustics on behalf of the Township of Amaranth, and the MOE. Several drafts of the protocol were prepared, and the final version, dated September 17, 2007 forms the basis of the measurement methodology underlining this audit report, and is attached as Appendix A. This audit represents the first of four seasonal audits that will be conducted at the transformer station.

Site Description

The TS is located on the east side of 10th Line, south of 15th Side Road, in Amaranth Township, County of Dufferin. There is one 100 MVA GE Prolec transformer on the TS site, along with supporting ancillary facilities. Figure 1A shows the TS in relation to the surrounding roads and residences, and Figure 1B illustrates the TS itself. Photo Plate 1 shows the acoustic barrier wall shielding the nearest residences from the transformer.

There are five residences near the TS. One of these is the participating landowner and is not considered in this assessment. The three closest residences are the key receptor locations, and these are described in Table 1, with the Receptor ID following the nomenclature used in the original Aercoustics report.

Table 1. Summary of Receptors.

ID Description Distance from Substation [m]

R01 214292 10th Line – northwest of TS 390 R02 214242 10th Line – southwest of TS 360 R04 214215 10th Line – south of TS 490

Receptor R01 is located to the northwest of the TS, and is partially illustrated by Photo Plate 2. A number of trees exist around the home and barn, but the area is otherwise quite open, with fields surrounding the structures.

Receptor R02 is the closest home to the TS, and is partially illustrated by Photo Plate 3. The area around the home and work shed is nearly entirely exposed, with no significant trees.

Receptor R04 is heavily treed, and considerable background sound results from these trees. Two barns exist on the property, which is partially illustrated by Photo Plate 4.


Criteria

Under the MOE’s guideline NPC-232 “Sound Level Limits for Stationary Sources in Class 3 Areas (Rural)”, the most stringent of the applicable criteria is 40 dBA during the nighttime hours (23:00 to 07:00). This sound level criterion has been selected as the governing sound level limit for the TS.

MOE guideline NPC-104, “Sound Level Adjustments”, specifies a 5 dB penalty for a tonal sound source such as a transformer. Applying the penalty to the sound levels produced by the operation of the TS to the criterion results in an effective criterion is 35 dBA (5 dB less than the 40 dBA criterion).

Canadian Hydro is proposing to install a second transformer on the site in order to service power for the proposed Melancthon II Wind Plant. The new transformer is proposed for installation beside the existing unit, but we understand that additional acoustic treatments are being considered. The 35 dBA effective sound level will apply to the TS as a whole. If the sound level impact of each of the two transformers and associated equipment is 32 dBA or less at the most impacted closest receptor, then the aggregate impact will meet the 35 dBA requirement (32 dBA plus 32 dBA results in a combined sound level of 35 dBA). Thus, 32 dBA is used as the effective target sound level for the existing equipment in this report.

It is important to realize that the guideline documents of the MOE do not require that noise from sound sources be inaudible at a residence. In fact, it should be understood that in a very quiet rural environment, a sound level of 35 dBA will be audible at times.

The sound level limits of the MOE guidelines are presented in terms of hourly energy equivalent average sound levels, designated LEQ. This means that if sound levels vary somewhat over an hour, it is the average sound level rather than the maximum or minimum sound levels which is relevant.

Background sound levels are also at times quantified by determining the ninetieth percentile (L90) sound level. An L90 sound level represents the level which was exceeded 90% of the time during a measurement. NPC-232 indicates that using the L90 to determine sound level criteria is appropriate in some cases, although under the guideline a criterion derived in this way can not be less than the 40 dBA upon which the 32 dBA target level is based; this audit uses the most stringent criterion of the MOE. L90 sound levels are also useful as they allow some separation of steady sound from an overall measured sound level. That is: when a continuous steady sound is masked at times by transient sounds such as those caused by wind gusts, birds, vehicles, and animals, the L90 sound level tends to more accurately reflect the sound level impact of the stationary sound by itself than does the LEQ sound level.


Measurement Methodology

The study is based on a complex collection of data series, obtained during the period from Monday, October 1 to Tuesday, October 9, 2007. A week-long period was chosen to collect data under a variety of weather conditions, and to include periods of different ambient sound conditions including day and night periods, and weekday and weekend periods.

Non-acoustic Data

Various measurements of non-acoustic quantities such as wind speed and power production were required to conduct this audit. To acquire this information, a number of actions were taken:

• On October 2, an automatic meteorological station was deployed at receptor R02 to record wind speed, wind direction, temperature and humidity. This data is attached to this report as Appendix B;

• Canadian Hydro deployed a current logging system to record any periods where the transformer fans were in operation before the acoustic measurements commenced on October 1;

• The residents agreed to record observations regarding the subjective impact of the sound of the TS throughout the measurement period. Summaries of the residents logs are attached to this report as Appendix C;

• Following the measurements, power production data was also acquired from Canadian Hydro and from the IESO. The data is attached as Appendices D and E, respectively. The data obtained directly from Canadian Hydro agreed with the IESO data.

Unattended Acoustic Measurements

Seven unattended sound level meters were deployed, and configured to record energy equivalent average (LEQ) sound levels in 10-minute intervals. L90 sound levels were also recorded. The locations of these instruments are shown on Figures 1A and 1B. Descriptions of the meters are provided in the Instrumentation section of this report, and records of the measurements are included in Appendixes F and G.

Three sound level meters were deployed inside the TS fenceline, about two metres west of the east fence and thus about 30 metres from the centre of the transformer. These three locations are identified as Locations 1, 2 and 3 on Figure 1B. These monitors were on the transformer side of the acoustic barrier wall, with a line of sight to the equipment. One of these three was positioned to the northeast of transformer, one to the east and one to the southeast, but all with a view of the transformer. Three instruments were used at this location, rather than a single instrument, in order to provide some spatial averaging of the sound levels near the transformer.


One sound level meter was placed on the switch side of the acoustic barrier wall (Location 4), approximately 30 metres from the centre of the transformer, monitoring noise from the switchgear. Observations indicated that at the time, the transformer audibility was very low at this location.

One instrument was then placed at each of the three residences described in Table 1, near to the dwellings. Locations were selected in conjunction with discussions with the residents, and were generally near the houses themselves, with no more acoustic screening from the TS than the homes themselves experienced.

Attended Acoustic Measurements

Attended measurements were made at the receptors during both daytime and nighttime hours during the period from October 4 to October 5, 2007. Observations as well as sound levels were made. The instrumentation used for the attended measurements is described in the Instrumentation section of this report.

A variety of attended measurements were also conducted at various locations around the TS on October 4, 2007. These latter measurements were generally intended to:

• Investigate the spectrum of the noise radiated by the TS;

• Verify typical sound levels emitted by the TS and radiated in different directions;

• Investigate propagation of sound with distance from the TS;

• Ensure that the acoustic barrier wall is providing attenuation to the noise from the transformer;

• Investigate the potential significance of noise from the transformer cooling fans;

• Investigate the potential significance of power production at the wind farm on the noise of the transformer.

Measurements were conducted simultaneously at three locations to the south, east, and northwest, of the transformer at a distance of about 30 to 40 metres. These locations are identified in Figure 1B as Location 8 through Location 10, respectively. At this distance, the sound of the TS was clearly the dominant source of noise. The three locations were then moved further from the TS to investigate propagation with distance. As requested by the MOE, the microphones were manually swept in a continuous fashion over as large an area as practical while standing in one spot in an attempt to minimize any local effects of acoustic radiation patterns, modal interference, small-scale shielding phenomena, etc. which might cause variations in measured sound level from location to location. Several cycles of microphone location changes occurred during each 5 minute measurement. Larger swept areas were not used as footsteps were found to generate excessive noise.


Specific TS operating conditions were investigated by forcing the cooling fans on and then off, and by shutting down all wind plant turbines for a period of about 15 minutes during the measurements.

Instrumentation

MOE publication NPC-102, “Instrumentation” provides specifications for sound level measurement instrumentation. All equipment used in the Audit meets these requirements.

Unattended Acoustic Measurements

Six Bruel & Kjaer Integrating Sound Level Metres were used for the unattended monitoring, together with a Larson Davis sound level analyzer. The instruments are described in Table 2, below.

Table 2: Instrumentation used For Unattended Sound Level Measurements

Measurement Location Instrument Make and Model Instrument Serial Number

Inside fenceline, NE location Bruel and Kjaer Type 2238 2448501 Inside fenceline, E location Bruel and Kjaer Type 2236 2039554 Inside fenceline, SE location Larson Davis LxT 0001724 Inside fenceline, SW location Bruel and Kjaer Type 2236 1735525 Receptor R01 Bruel and Kjaer Type 2238 2262611 Receptor R02 Bruel and Kjaer Type 2238 2562612 Receptor R04 Bruel and Kjaer Type 2238 2343948

Both of the 2236 and 2238 sound level meters meet the specifications contained in NPC-102, however the newer Type 2238 sound level has replaced Type 2236 in the Bruel and Kjaer catalogue. The clocks of all seven instruments were synchronized.

Correct calibration of the acoustic instrumentation was verified using Bruel and Kjaer and Rion acoustic calibrators. Wind screens were used on all microphones, consistent with the requirements of NPC-103, “Procedures”.

Meteorological data was collected using a Davis Instruments Corp. Vantage Pro2 weather station, equipped with an anemometer, wind vane, thermometer, hygrometer and barometer. The system was configured to record data in 10 minute intervals. The MOE guidelines indicate that sound level measurements should not be conducted during periods with high wind speeds. Specifically, NPC-102 indicates that measurements of low sound levels should not be undertaken when winds exceed 15 km/h. However, as the winds in Amaranth Township are frequently strong, making the


area the subject of interest for wind farm projects, some consideration of the sound level during higher wind speeds is appropriate. The data from the weather station is presented in Appendix B.

Attended Acoustic Measurements

Three Hewlett Packard Type 3569A Real Time Frequency Analyzers (serial numbers 3222A00134, 3222A00199 and 3442A00141), in conjunction with Bruel & Kjaer Microphones, were used for the attended measurements. Correct calibration of the acoustic instrumentation was verified using Bruel and Kjaer and Rion acoustic calibrators. Wind screens were used on all microphones, consistent with the requirements of NPC-103.

Assessment and Discussion

Unattended Acoustic Measurements – Transformer Station

Figure 2 shows the sound levels measured at four points around the transformer, within the fenced area. The northeast, east and southeast locations (Locations 1 through 3) are near the transformer, and on the transformer side of the acoustic barrier wall; they show relatively steady levels of 45 to 55 dBA over the week. Site observations indicate that sound from the TS is clearly the dominant noise at these locations. In the absence of unusual phenomena, a sound level of 55 dBA at a distance of 30 metres from the transformer would be expected to result in a sound level of about 33 dBA at the closest residence (360 metres away), not accounting for the effect of the acoustic barrier wall or the absorption of sound by the air and ground. Thus, the unattended sound level measurements at the TS indicate that the impact of the transformer itself should be in compliance with the MOE guideline limits at the closest residences, even with no acoustic barrier wall.

The southwest monitor location (Location 4) is near the switch gear, on the opposite side of the acoustic barrier wall from the transformer, and any noise generated here would not be appreciably shielded from the residences. On occasion, the sound levels on this side of the barrier are significantly higher than on the transformer side of the barrier; sound levels of up to 70 dBA were recorded. This is a major anomaly, possibly due to corona noise on the wires or switch gear, but insects or wind in the trees located on the nearby berm are also possible contributors. While HGC Engineering personnel were on site, sound levels at this location were significantly lower, but at those times, noise from the wires and switch gear on the switch side of the barrier was the dominant sound. This phenomenon of higher sound levels at this location will be investigated in greater detail during future work.

Figure 2 also shows the background (L90) sound levels recorded at the residences at times corresponding with the time of day noted in the residents’ observation logs. The L90 sound level is cited in this case as it is a better indicator of the steady sound at the measurement location, rather than the aggregate sound of all sound sources. The logs are summarized in Appendix C. The comments in the logs, together with the corresponding times and measured sound levels, indicate


that the residents typically notice the TS noise when the background sound levels are low, not when the overall sound levels, including all sounds at the receptor, is high.

For example, the resident at R02 in particular observed notable audibility (6 out of 10) when the L90 sound level was in the range from 20 to 28 dBA, well below MOE guidelines. Also, a resident at R01 reported the noise to the MOE when the L90 was 22 dBA. While this indicates that the impact of the TS is most objectionable when background sound is low, and audibility of the TS is therefore relatively high, it also tends to suggest that the impact of the TS was in compliance with the MOE guideline limits during the measurement period.

Figure 3a is a spectrogram of the unattended spectral measurements conducted at the southeast unattended measurement location. The figure confirms that the sound levels vary with time, but that the dominant A-weighted frequency bands (i.e., 400 and 500 Hz) do not appreciably vary with time. Figure 3b represents the same measurement location, but the instrument was temporarily reconfigured for greater temporal resolution for this time period (14:15 to 18:30 on October 4). The influence of the small air conditioning unit on the on-site control building can be seen as regular fluctuations in the magnitude of the sound levels.

Figure 4 adds a record of the electrical power monitored at the wind farm to the TS sound level data shown in Figure 2. The figure shows that there is no meaningful correlation between the wind plant power output and the sound levels at the transformer.

Figure 5 overlays the weather data on the sound levels near the transformer. No obvious correlations with wind speed, temperature or humidity exist with the sound levels monitored on the transformer side of the acoustic barrier wall. However, there appears to be a correlation between the sound levels monitored on the switch side of the barrier wall with both higher wind speeds and temperature. This correlation suggests that wind-induced noise such as the wind in the trees may be causing the elevated noise in this area, or that corona noise, if such is the case, is high when the temperature and/or the wind are high.

Unattended Acoustic Measurements – Residences

Figure 6 illustrates overall unattended sound levels measured at the residences. The levels are obviously influenced by wind and local activities, and include the sound of aircraft, distant and local vehicles, animals and voices as well as any sound from the TS. In particular, the heavily treed nature of R04 results in significant wind-induced noise even in relatively light wind conditions. This, combined with the animal activities at R04, likely explained the many spikes in the measured sound level data at this location.

The data summarized in Figure 6 show that the nighttime sound levels (when local activity is relatively low) at the residences are below 30 dBA on several occasions when the TS is producing noise. This fact indicates compliance with the 32 dBA target sound level, during those times.


Figure 7 adds unattended measurement data from the TS to the unattended data at the residences. As shown, there is little correlation between the sound on the transformer side of the acoustic barrier wall and the sound levels at the residences, although there may be some correlation with the sound on the switch side of the barrier wall. This tends to suggest that while the sound levels at the residence are varying, the contribution of the transformer by itself was not a dominant contributor sound levels measured at the residences.

Figure 8 illustrates the sound levels at the residences against the weather data. The local wind seems to correlate closely with the measured sound levels, rather than with the TS sound levels, demonstrating that the wind causes noise at the residences.

The fact that the sound levels at the residences was not correlated with the sound levels at the TS, the fact that the sound levels at the residences were at times less than 30 dBA when the TS was operating and producing noise, and the fact that the sound levels at the residences seems to correlate closely with the wind speed, indicates that the impact of the transformer was in compliance with the MOE guidelines during the measurement period.

Attended Acoustic Measurements – Transformer Station

Figure 9 illustrates minute measurements conducted simultaneously over a 5 minute period at three locations (Locations 8 through 10) around the TS, 30 to 40 metres from the centre of the transformer. Location 9 is not shielded from the transformer by the acoustic barrier wall, but is partially screened by fixed site equipment, whereas Locations 8 and 10 locations are shielded by the barrier wall, as are the residences. The distances were somewhat forced by the site geometry; any closer and Location 9 would have been affected by an acoustic reflection off of a large retaining wall, and any further and Location 8 would have been behind an earthen berm. The latter half of the 5 minute measurement was significantly affected by aircraft, and is not considered here. Thus, Figure 9 represents the LEQ spectra of the first 2.5 minutes of the measurement. The figure indicates tonal noise, with principal frequencies in the 50, 125 and 400 Hz 1/3 octave bands, and with the tone in the 400 Hz band as the dominant audible frequency.

During these measurements, the microphone was continuously swept over as wide an area as practical while standing still, with several cycles of microphone location occurring during each measurement.

Figure 10 illustrates how the noise of the transformer, represented by the 400 Hz octave band, varied with time and microphone location at the measurement locations. There is variation at all three locations, as a result of variations in location screening, refractions and reflections from moment to moment as the microphones are moved.

The attended measurements at Locations 8 through 10 were repeated with the transformer cooling fans forced on. At none of the three locations were the fans audible at all. The record provided by


Canadian Hydro of electrical current running to the fan motors indicated that this was the only time during the automated measurement period that the fans operated.

We understand that the transformer must be de-energized for the tap to be changed, and that the tap must be changed manually. Consequently, changes in tap position do not occur regularly, and we understand that the tap was in ‘position 2’ throughout the measurements.

Figures 11 and 12 summarize a similar set of measurements made when all turbines at the wind plant had been shut off. A comparison of these figures with Figures 9 and 10 indicates that the transformer noise at locations most exposed to the transformer, such as Location 9, does not appear to change when the wind plant is not producing power. Subjectively, no audible difference in sound was noted when the wind plant was shutdown.

Figure 13 shows sound level spectra obtained by approximately doubling the distance between the instruments and the transformer. In the east and south directions, the sound levels fell off markedly. The fact that the northwest direction did not fall off significantly is explained by the fact that the location is nearer and more exposed to road traffic on 10th Line.

Several Fast Fourier Transform (FFT) measurements were conducted at Location 9, approximately 40 metres from the transformer. These measurements are summarized on Figure 14, which illustrates the frequency makeup of the sound of the transformer in some detail. As expected, the sound is clearly tonal, and set by peaks at 120, 240 and 360 Hz, with other harmonics present. These three peaks are contained within the 125, 250 and 400 Hz 1/3 octave bands shown in Figure 9.

Attended Acoustic Measurements – Residences

Attended measurements were also conducted at each of the residences a few times, and the results are summarized in Table 3. These are short-duration measurements, generally one minute long, taken at moments when the influence of extraneous noises (e.g., wind noise, dogs, birds, farm animals, speech, cars and aircraft) was low.


Table 3: Summary of Attended Measurements at Receptors

Location Date and Time

LEQ [dBA]

L90 [dBA] Comments

34 33 Oct 4, 2007 17:36 38 31

TS inaudible. Dog, insects, distant traffic, distant tractor dominant.

33 31 37 32

R01 Oct 5, 2007

01:15 33 32

Transformer hum faintly audible. Minimal animal activity, fog.

35 30 Oct 4, 2007 18:02 32 30

TS inaudible. Distant traffic dominant.

32 30 Oct 4, 2007 19:20 35 31

TS inaudible. Distant traffic and insects dominant, distant voices, dog present.

35 32 34 32

R02

Oct 5, 2007 02:10

33 33

Transformer hum audible. Resident at R02 indicates a 6/10. Distant dogs audible.

Oct 4, 2007 19:43 35 30 TS inaudible.

Barn animals, aircraft dominant. 33 31

33 31 R04 Oct 5, 2007

01:50 34 31

Transformer hum faintly audible. Animals audible.

As shown in Table 3 indicates, the measured LEQ sound levels were in a fairly tight range: 32 to 38 dBA over all the measurements, with the L90 sound levels ranging from 30 to 33 dBA. While during all measurements, the LEQ sound level at the receptors exceeded the 32 dBA criterion, this does not by itself indicate that the impact of the TS exceeds the criterion. These measured sound levels represent the aggregate sound level due to all sound sources in the area including sound from distant vehicles, farm animals, distant and local dogs, insects, birds, talking and wind-induced noises. As the measurements include the effect of these intermittent and extraneous sound sources, the measured L90 represent a better estimate of the steady sounds, including the noise from the TS.

As Table 3 indicates, the TS noise was audible at some times, and inaudible at others. It can safely be stated that when the TS was not audible, it is not contributing to any meaningful degree to the measured sound levels, and the impact of the TS by itself was thus well below the measured 30 to 33 dBA L90 sound levels. The fact that the sound levels do not appear to have increased


when the TS became audible tends to suggest that the contribution of the TS to the measured sound levels was also lower than the measured L90 sound levels when the TS was audible.

In fact, because the TS was not audible at all during some of these times, the actual impact of the TS by itself may be less than the measured L90 sound levels.

In an attempt to further quantify the impact of the TS at the residences, a series of FFT measurements were made at each location during the nighttime, when the transformer hum was audible. These are summarized in Figure 15. As the figure indicates, the tones from the transformer could not be measured by the instrument at that time, implying that they were below the noise floor of the equipment, less than the 10 to 20 dB shown in the data.

Summary and Conclusions

1) The measurements show no particular correlation between the sound levels at the residences and the sound levels near the transformer. The sound at the residences is at times less than 30 dBA during periods when the TS is operating and producing noise. The sound at the residences correlated more closely with wind speed. These facts suggest that the impact of the TS was in compliance with the target 32 dBA sound level during the measurement period.

2) The logs of the residents’ observations, together with the sound levels measured during the times of the observations indicate that the impact of the TS was often considered objectionable when background sound was low, indicating that the concerns may be more related to audibility in a very quiet environment rather than to the numerical sound level impact.

3) While no evidence of unusual acoustic phenomena was found on the transformer side of the barrier, and the transformer fans are not an issue, there were periods when the sound levels on the switch side of the acoustic barrier wall were high. This may be due to wind, insects or birds in the nearby trees, which would have been shielded from the other three on-site unattended measurement locations. Alternately, these elevated sound levels may have been due to corona noise from the switch gear. Further investigation of this phenomenon will be made during subsequent studies.

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20304050607080

Mon, Oct 01, 00:00

Tue, Oct 02, 00:00

Wed, Oct 03, 00:00

Thu, Oct 04, 00:00

Fri, Oct 05, 00:00

Sat, Oct 06, 00:00

Sun, Oct 07, 00:00

Mon, Oct 08, 00:00

Tue, Oct 09, 00:00

Wed, Oct 10, 00:00


010203040506070

Wind Farm Power Production [MW]

Loca

tion

3Lo

catio

n 4

Loca

tion

2Lo

catio

n 1

Pow

er D

ata

from

IES

OP

ower

Dat

a fro

m C

andi

an H

ydro

Figu

re 5

: Su

mm

ary

of O

vera

ll L E

QSo

und

Leve

l Dat

a C

olle

cted

Aut

omat

ical

ly

With

in th

e A

mar

anth

Tra

nsfo

rmer

Sta

tion,

Plot

ted

Aga

inst

Met

erol

ogic

al D

ata,

Oct

ober

200

7

2030405060708090100

Mon, Oct 01, 00:00

Tue, Oct 02, 00:00

Wed, Oct 03, 00:00

Thu, Oct 04, 00:00

Fri, Oct 05, 00:00

Sat, Oct 06, 00:00

Sun, Oct 07, 00:00

Mon, Oct 08, 00:00

Tue, Oct 09, 00:00

Wed, Oct 10, 00:00

Overall A-Weighted Sound Pressure Level [dBA], Humidity [%]

048121620242832

Temperature [C], Ground Level Wind Speed [m/s]

Loca

tion

3Lo

catio

n 4

Loca

tion

2Lo

catio

n 1

Hum

idity

Rai

nTe

mpe

ratu

reW

ind

Win

d S

peed

Figu

re 6

: Su

mm

ary

of O

vera

ll L E

Q S

ound

Lev

el D

ata

Col

lect

ed A

utom

atic

ally

at t

he

Res

iden

ces,

Oct

ober

200

7O

vera

ll so

und

leve

ls in

clud

es th

e ef

fect

of a

ll so

und

souu

rces

incl

udin

g w

ind,

veh

icle

s, a

nim

als,

etc

.

20304050607080

Mon, Oct 01, 00:00

Tue, Oct 02, 00:00

Wed, Oct 03, 00:00

Thu, Oct 04, 00:00

Fri, Oct 05, 00:00

Sat, Oct 06, 00:00

Sun, Oct 07, 00:00

Mon, Oct 08, 00:00

Tue, Oct 09, 00:00

Wed, Oct 10, 00:00


Loca

tion

7 (R

04)

Loca

tion

5 (R

01)

Loca

tion

6 (R

02)

Figu

re 7

: Su

mm

ary

of O

vera

ll So

und

Leve

l Dat

a C

olle

cted

Aut

omat

ical

ly a

t the

R

esid

ence

s, W

ith O

vera

ll So

und

Leve

l Dat

a at

the

Tran

sfor

mer

Sta

tion,

Oct

ober

200

7O

vera

ll so

und

leve

ls in

clud

e th

e ef

fect

of a

ll so

und

sour

ces

incl

udin

g w

ind,

veh

icle

s, e

tc.

20304050607080

Mon, Oct 01, 00:00

Tue, Oct 02, 00:00

Wed, Oct 03, 00:00

Thu, Oct 04, 00:00

Fri, Oct 05, 00:00

Sat, Oct 06, 00:00

Sun, Oct 07, 00:00

Mon, Oct 08, 00:00

Tue, Oct 09, 00:00

Wed, Oct 10, 00:00


Loca

tion

7 (R

04)

Loca

tion

5 (R

01)

Loca

tion

6 (R

02)

Loca

tion

4Lo

catio

n 1

Figu

re 8

: Su

mm

ary

of O

vera

ll So

und

Leve

l Dat

a C

olle

cted

Aut

omat

ical

ly

at th

e A

mar

anth

Tra

nsfo

rmer

Sta

tion,

With

Met

erol

ogic

al D

ata,

Oct

ober

200

7O

vera

ll so

und

leve

ls in

clud

es th

e ef

fect

of a

ll so

und

souu

rces

incl

udin

g w

ind,

veh

icle

s, a

nim

als,

etc

.

2030405060708090100

Mon, Oct 01, 00:00

Tue, Oct 02, 00:00

Wed, Oct 03, 00:00

Thu, Oct 04, 00:00

Fri, Oct 05, 00:00

Sat, Oct 06, 00:00

Sun, Oct 07, 00:00

Mon, Oct 08, 00:00

Tue, Oct 09, 00:00

Wed, Oct 10, 00:00

Overall A-Weighted Sound Pressure Level [dBA], Humidity [%]

048121620242832

Temperature [C], Ground Level Wind Speed [m/s]

Loca

tion

7 (R

04)

Loca

tion

5 (R

01)

Loca

tion

6 (R

02)

Hum

idity

Rai

nTe

mpe

ratu

reW

ind

Spe

ed

Figu

re 9

. A

ttend

ed A

-Wei

ghte

d L E

QSo

und

Leve

l Spe

ctra

Mea

sure

d 30

to 4

0 m

etre

s fr

om T

rans

form

erM

easu

rem

ents

Con

duct

ed O

ctob

er 4

, 200

7

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

2531.5

40506380

100125160200250315400500630800

1000125016002000250031504000500063008000

10000125001600020000

dBA

1/3

Oct

ave

Ban

d C

entr

e Fr

eque

ncy

[Hz]

Sound Pressure Level [dBA]

Loca

tion

9Lo

catio

n 8

Loca

tion

10

Figu

re 1

0: A

-Wei

ghte

d Ti

me

Sign

als

- 400

Hz

1/3

Oct

ave

Ban

d,M

easu

rem

ents

Con

duct

ed 3

0 to

40

met

res

from

Tra

nsfo

rmer

, Oct

ober

4, 2

007

Fluc

tuat

ions

in S

ound

Lev

el d

ue to

Mic

roph

one

Mov

emen

t

1020304050607080

17

1319

2531

3743

4955

6167

7379

8591

9710

310

911

512

112

713

313

914

5

Tim

e [s

]

Sound Pressure Level [dB]

Loca

tion

9Lo

caito

n 8

Loca

tion

10

Figu

re 1

1. A

ttend

ed A

-Wei

ghte

d LE

Q S

ound

Lev

el S

pect

ra M

easu

red

30 to

40

met

res

from

Tra

nsfo

rmer

Mea

sure

men

ts C

ondu

cted

Oct

ober

4, 2

007

Fluc

tuat

ions

in S

ound

Lev

el d

ue to

Mic

roph

one

Mov

emen

t

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

2531.5

40506380

100125160200250315400500630800

1000125016002000250031504000500063008000

10000125001600020000

dBA

1/3

Oct

ave

Ban

d C

entr

e Fr

eque

ncy

[Hz]


Loca

tion

9Lo

catio

n 8

Loca

tion

10

Figu

re 1

2: A

-Wei

ghte

d Ti

me

Sign

als

- 400

Hz

1/3

Oct

ave

Ban

d,M

easu

rem

ents

Con

duct

ed 3

0 to

40

met

res

from

Tra

nsfo

rmer

, Oct

ober

4, 2

007

Win

d Fa

rm N

ot P

rodu

cing

Ele

ctric

ityFl

uctu

atio

ns in

Sou

nd L

evel

due

to M

icro

phon

e M

ovem

ent

1020304050607080

17

1319

2531

3743

4955

6167

7379

8591

9710

310

911

512

112

713

313

914

5

Tim

e [s

]


Loca

tion

9Lo

catio

n 8

Loca

tion

10

Figu

re 1

3. A

ttend

ed A

-Wei

ghte

d LE

Q S

ound

Lev

el S

pect

ra M

easu

red

70 to

80

met

res

from

Tra

nsfo

rmer

Mea

sure

men

ts C

ondu

cted

Oct

ober

4, 2

007

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

2531.5

40506380

100125160200250315400500630800

1000125016002000250031504000500063008000

10000125001600020000

dBA

1/3

Oct

ave

Ban

d C

entr

e Fr

eque

ncy

[Hz]


80 m

etre

s ea

st o

f tra

nsfo

rmer

70 m

etre

s S

outh

of t

rans

form

er70

met

res

Nor

thea

st o

f tra

nsfo

rmer

Figu

re 1

4: D

iscr

ete

Freq

uenc

y (F

FT) S

ound

Spe

ctra

Mea

sure

d at

Loc

atio

n 9,

Mea

sure

men

ts C

ondu

ted

Oct

ober

4, 2

007

55 d

B, 3

60 H

z

102030405060708090100

050

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

Freq

uenc

y [H

z]


Figu

re 1

5: D

iscr

ete

Freq

uenc

y (F

FT) S

ound

Spe

ctra

M

easu

red

at L

ocat

ion

9 an

d A

t Res

iden

ces

Mea

sure

men

ts C

ondu

ted

Oct

ober

4, 2

007

-1001020304050607080

050

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

Freq

uenc

y [H

z]


Loca

tion

9 (T

S)

Loca

tion

5 (R

01)

Loca

tion

7 (R

04)

Loca

tion

6 (R

02)

Photo Plate 1: Part of the TS, Looking East

Photo Plate 2: Sound Level Meter Installed at Receptor R01, Looking Southwest

Photo Plate 3: Sound Level Meter Installed at Receptor R02, Looking South

Photo Plate 4: Sound Level Meter Installed at Receptor R04, Looking South. This monitor was later moved to a location near the front door.

mr. geoff carnegie canadian hydro developers, …...november 22, 2007 mr. geoff carnegie canadian...

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