Mr. Scott Hossie Canadian Hydro Developers, Inc. 34 ... Hydro...Mr. Scott Hossie Canadian Hydro Developers, Inc. 34 Harvard Road ... Manufacturer sound level test results for both

October 27, 2008 Mr. Scott Hossie Canadian Hydro Developers, Inc. 34 Harvard Road Guelph, ON N1G 4V8 Re: Summer 2008 Acoustic Audit Amaranth Transformer Station, Melancthon I Wind Plant Certificate of Approval (Air) Number 2233-6X9NBQ Dear Mr. Hossie,

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 fourth and final audit of four seasonal audits that have been conducted to assess the impact of the TS noise, as a condition of Certificate of Approval (Air) Number 2233-6X9NBQ issued October 17, 2007 by the Ministry of the Environment (MOE).

The previous acoustic audits (autumn 2007, winter 2008 and spring 2008) were conducted to assess the impact of a GE Prolec transformer. The GE transformer has since been removed from the site and replaced with a Siemens TP-720 transformer. This summer 2008 acoustic audit was conducted with the new Siemens transformer. In addition, the acoustic barrier wall, which was originally open to the east side of the transformer, has been extended on the east side, fully enclosing the transformer.

The results of the summer 2008 audit and the overall conclusions from the four seasonal audits are summarized below:

1. The data recorded in the summer 2008 audit indicates that the noise contribution from the

TS at the three closest residences was in compliance with the MOE sound level limits during the measurement period. This is consistent with the results of the three previous acoustic audits.

Canadian Hydro Developers, Inc., Page 2 Summer 2008 Acoustic Audit, Amaranth Transformer Station October 27, 2008

2. The comment logs of the residents’ observations during the four seasonal acoustic audits and the sound levels measured during the times of the observations indicated that the impact of the TS is often considered objectionable when background sound is low, indicating that the concerns may be more related to audibility in a very quiet environment rather than to the absolute magnitude of the sound level impact. By itself, audibility does not indicate non-compliance with the MOE guidelines.

3. Results obtained during the autumn 2007 audit indicated periods when the sound levels on

the switch side of the acoustic barrier wall were occasionally higher than expected. The unexplained sound levels could have been attributable to the wind, insects, birds in the nearby trees, and/or corona noise. The presence of corona noise was not clearly identified in any of the three seasonal audits that followed the autumn 2007 audit.

4. There is evidence to suggest that the new Siemens TP-720 transformer is quieter than the

previous GE Prolec transformer, although the replacement of the transformer has not eliminated the occasional audibility at the receptor locations. The sound levels measured in this summer 2008 acoustic audit have been compared to the results obtained in the three previous audits; however, as a result of the simultaneous change in transformer and the addition to the barrier wall, the increased amount of onsite activity in the form of construction, and the fact that the audits have all been conducted during different seasons, it is difficult to quantify the exact magnitude of the sound level reduction. The lab test results, from the manufacturer, confirm that the Siemens transformer is quieter than the original GE transformer.

The summer 2008 acoustic audit is presented in the following sections. We trust that this information is sufficient for your current needs. Please let us know if you have any further questions or concerns. Yours truly, Howe Gastmeier Chapnik Limited

Megan Munro, BASc, EIT Brian Howe, MEng, MBA, PEng


Introduction

This summer 2008 acoustic audit of the Amaranth Transformer Station (“TS”), situated in the Township of Amaranth, County of Dufferin, followed the requirements of the Ministry of the Environment’s (“MOE”) technical publication NPC-233 “Information to be Submitted for Approval of Stationary Sources of Sound”. The audit also employed the additional methodology described in a letter prepared by HGC Engineering, dated September 17, 2007, as agreed to by Dr. Al Lightstone of Valcoustics Canada Ltd. (“Valcoustics”) as the Township’s acoustical specialist and John Kowalewski of the MOE. This letter, developed with input from the surrounding residents, is attached as Appendix A for continued reference.

The audit methodology was revised based on the results of the autumn 2007 audit. The revisions to the methodology are described in a letter prepared by HGC Engineering, dated January 24, 2008 and is attached as Appendix B. Further to this, the autumn 2007 and winter 2008 audits showed no correlation between turbine operation and sound levels at the TS. Based on this conclusion, HGC Engineering did not request that Canadian Hydro stop all turbines for a brief period during the spring or summer audits.

As per the audit methodology prescribed for the Amaranth TS, the acoustic audit was based upon a complex series of attended and unattended sound measurements and other data recorded between August 5 and August 18, 2008. These included:

• attended and automated unattended sound level measurements conducted on the TS site; • attended and automated unattended sound level measurements conducted at the three principal

receptors adjacent to the TS; • electrical power data provided by Canadian Hydro Developers, Inc. (“Canadian Hydro”) and

verified against Independent Electrical System Operator (“IESO”) data for the same period; • meteorological data monitored at one of the residences during the measurement period; and • the residents’ own logs of observations made during the measurement period. Throughout this acoustic audit report the acronym ‘TS’ is used to refer to the Amaranth Transformer Station as a whole. However, there are times when the transformer itself is meant, and at these times the word ‘transformer’ is used.

The GE Prolec transformer was recently replaced with a Siemens TP-720 transformer. This summer 2008 acoustic audit is based on this new transformer, whereas the three previous audits (autumn 2007, winter 2008 and spring 2008) were conducted with the GE Prolec transformer. In addition, the acoustic barrier wall, which was originally open to the east side of the transformer, has been extended on the east side, fully enclosing the transformer.


Certificate of Approval – Air

Certificate of Approval – Air (“CofA”) Number 2233-6X9NBQ requires that Canadian Hydro undertake four seasonal, post-abatement acoustical measurements of the Amaranth TS. In this regard, Canadian Hydro has retained HGC Engineering to independently carry out the measurements.

HGC Engineering has previously completed three seasonal acoustical measurements in the autumn of 2007, the winter of 2008 and the spring of 2008. These reports, which can be viewed on the project website (www.melancthonwind.com), should be read in conjunction with this report as they provide the background and basis for the measurements. This audit represents the fourth and final of four seasonal audits that have been conducted at the Amaranth TS for the Melancthon I Wind Plant.

The three previous audits indicated that the Amaranth TS was operating in compliance with the applicable MOE sound level limits. During the autumn 2007 audit the measurements showed an intermittent and unexplained increase in sound on the west side of the TS that was not correlated to an increase in sound on the east side. This audit, as well as the previous audits attempted to further investigate and explain this phenomenon.

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 are five residences adjacent to the general area of the TS. One of these is the participating landowner and is not considered in this assessment given their association with the facility. The three closest residences are the key receptor locations, described in Table 1, with the Receptor ID following the nomenclature used in the original acoustical report prepared by Aercoustics Engineering Ltd. (August 2006). Figure 1A shows the TS in relation to the surrounding roads and residences.

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


Transformer Description

There is one 100 MVA Siemens TP-720 transformer on the TS site, along with supporting ancillary facilities. This is a new transformer unit. The previous acoustic audits (autumn 2007, winter 2008 and spring 2008) were conducted to assess the impact of the GE Prolec transformer, which has since been removed from the site. The new Siemens TP-720 transformer was installed in approximately the same location as the previous GE Prolec transformer. The new Siemens TP-720 transformer is approximately 7.4 m tall, 7.2 m wide and 5.2 m deep. A drawing of the transformer has been included in Appendix C.

During previous acoustic audits (autumn 2007, winter 2008 and spring 2008) there was an acoustic barrier to the north, west and south of the transformer. The transformer was exposed to the east. Since the spring 2008 audit, the acoustic barrier was extended to the east, enclosing the transformer. This audit (summer 2008) considers the barrier on all four sides.

Figure 1B illustrates the TS itself, including the acoustic barrier walls, the surrounding berm and the measurement locations. Photo Plate 1 shows the acoustic barrier wall shielding the nearest residences from the transformer.

Manufacturer sound level test results for both the GE Prolec transformer and the Siemens TP-720 transformer were provided by Canadian Hydro. The Siemens sound test was performed according to CSA CAN3 C88-M90. The GE sound test does not indicate which standard was used; however, it does indicate that sound pressure levels were measured at the ANSI surface, indicating compliance with an international standard. The tests were performed for two different test conditions; ONAN and ONAF-2. The difference between these two tests is the circulation method for external cooling. ONAN relies on natural convection (i.e. no fans) and ONAF utilizes forced air circulation.

The GE test results reported a sound pressure level of 76 dBA and the Siemens test results reported a sound pressure level of 69 dBA, under the ONAN test conditions. Under the ONAF-2 test conditions, the GE test results reported a sound pressure level of 81 dBA and the Siemens test results reported a sound pressure level of 72 dBA. According to these test results and assuming the test conditions were the same, the Siemens transformer has a lower sound pressure level than the GE transformer. The sound test results for the Siemens and GE transformers have been included in Appendix C and D respectively.

In the future, an additional Siemens TP-720 transformer will be installed just to the north of the existing transformer. The second transformer is being installed for the Melancthon II Wind Project. At the time of this audit construction was underway but the second transformer was not operating. A complete site plan, illustrating the locations of both transformers, has been included in Appendix C.


Sound Level Limits

As described in the autumn acoustical audit, after accounting for the tonality aspects of the transformers, the applicable MOE sound level limits for the Amaranth TS are:

• daytime (07:00 – 23:00 hrs): 40 dBA

• night-time (23:00 – 07:00 hrs): 35 dBA.

These criteria apply to the Amaranth TS as a whole, including any new transformer(s) or equipment that is added in the future. 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 likely 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.

Sound levels are sometimes usefully 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. Technical publication NPC-232 indicates that it is appropriate to use the background one hour ninetieth percentile sound level (L90) plus 10 dB if it results in a more stringent sound level limit than that obtained by considering the background one hour equivalent sound level (LEQ). L90 sound levels are useful as they allow some separation of steady sound from an overall, aggregate measured sound level. That is: when a continuous sound such as the sound of an operating transformer is masked at times by a louder transient sound such as those caused by wind gusts, birds, vehicles, and animals, the L90 sound level tends to more accurately reflect the sound level contribution of the steady 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 Tuesday, August 5 to Monday, August 18, 2008. More than 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 August 5th, an automatic meteorological station was deployed at receptor R02 to record wind speed, wind direction, temperature, and humidity. This data is attached to this audit as Appendix E;

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

• Following the measurements, power production data was also acquired from the IESO and Canadian Hydro. The data are attached as Appendices G and H, respectively. It is noted that based upon HGC Engineering’s review, the data obtained directly from Canadian Hydro generally agreed with the IESO data. There were two brief periods when the IESO data was less than the Canadian Hydro data.

Unattended Acoustic Measurements

Seven unattended sound level meters were deployed and configured to record 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 sound level meters are provided in the Instrumentation section of this report and records of the LEQ and L90 measurements are included in Appendices I and J, respectively.

Two 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 two locations are identified as Locations 1 and 3 on Figure 1B and shown in Photo Plates 2 and 3. These monitors were on the east side of the TS. Two 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 (Photo Plate 4). Observations indicated that during the measurement period, the transformer audibility was low at this location.

During the autumn 2007 audit the measurements showed an intermittent and unexplained increase in sound on the west side of the TS that was not correlated to an increase in sound on the east side. As such, during the winter, spring and summer acoustic audits an additional sound level meter was placed on the switch side of the acoustic barrier, on the berm, outside the transformer fencing (Location 11) to assist in investigating the unexplained increase. The location of this sound level meter is shown in Photo Plate 5.

One sound level meter was also 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 little to no acoustic screening from the TS to represent the same exposure the homes experienced.


Attended Acoustic Measurements

Attended measurements conducted over a series of one minute periods were made at the three receptors on August 12th and August 15th, 2008, as well as during the early morning hours of August 14th, 2008. Observations as well as sound level measurements were made. The instrumentation used for these 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 August 12th, 2008. These measurements, each conducted over a period of five minutes, were 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;

and • investigate the potential significance of power production at the wind plant 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 the dominant source of noise. The three locations were then moved further from the transformer 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 of the five minute measurements. Larger swept areas were not used as footsteps were found to generate excessive noise.

Instrumentation

MOE technical 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 and one Larson Davis Integrating Sound Level Meters were used for the unattended monitoring. 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 2343948 Inside fenceline, E location Larson Davis LxT 0001724 Inside fenceline, SW location Bruel and Kjaer Type 2238 2448501 Outside fenceline, SW location Bruel and Kjaer Type 2236 2151071 Receptor R01 Bruel and Kjaer Type 2236 1849429 Receptor R02 Bruel and Kjaer Type 2236 2562611 Receptor R04 Bruel and Kjaer Type 2236 2039554

Both of the Bruel and Kjaer 2236 and 2238 sound level meters meet the specifications contained in technical publication NPC-102, however, the newer Type 2238 sound level meter has replaced Type 2236 in the Bruel and Kjaer catalogue. The Larson Davis LxT also meets the specifications of technical publication NPC-102. The clocks of all seven instruments were synchronized before being deployed.

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 technical publication 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; consistent with the 10 minute interval recordings of the sound level meters.

The MOE guidelines indicate that sound level measurements should not be conducted during periods with high wind speeds or precipitation. Specifically, technical publication NPC-102 indicates that measurements of low sound levels should not be undertaken when winds exceed 15km/h. However, as the winds in Amaranth Township are frequently strong, making the area the subject of interest for wind plants, some consideration of the sound level during higher wind speeds is appropriate. The data from the weather station is presented in Appendix C.

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 technical publication NPC-103.


Assessment and Discussion

Unattended Acoustic Measurements – Transformer Station

This acoustic audit was conducted while construction activities were ongoing at the TS site. The construction activities were for the installation of the second transformer for the Melancthon II wind plant. During HGC Engineering’s site visits on August 5, August 12 and August 15, 2008 construction activities were the predominant source of noise in the area. According to discussions with workers on site, the construction was scheduled to occur Monday to Friday from 07:00 to 17:00 with the possibility of weekend overtime. Sound measurements taken during this period likely do not represent noise caused by the TS. Further to this, precipitation and high wind speeds (i.e, > 15 km/hr) may also impact the measured sound levels. Periods where precipitation occurred are highlighted in grey on Figures 2 and 4 through 8. The sound level monitor at Location 1 lost power between August 16 and August 18, 2008 resulting in no recorded data during this period.

Figure 2 shows the sound levels measured at three points around the transformer, within the fenced area, and the sound levels measured on the berm, about 50 meters SW of the transformer. The northeast and southeast locations (i.e., Locations 1 and 3) are near the transformer, on the east side of the new acoustic barrier wall. Sound levels recorded during the daytime Monday to Friday show elevated levels due to the ongoing construction activity. Sound levels measured during the morning of August 12, 2008 show elevated sound levels in part due to our presence on site.

Measurements at Location 1 show sound levels typically between 40 and 50 dBA during the measurement periods when bad weather and/or onsite activity did not adversely affect the measurements. At Location 3, measured sound levels typically ranged from 35 to 45 dBA, slightly less than at Location 1, when bad weather and/or onsite activity were minimal. As expected, given the close proximity to the transformers, site observations indicate that sound from the TS is clearly the dominant noise at these locations.

The sound levels measured at Locations 1 and 3 during this summer 2008 acoustic audit are generally lower than the levels measured at these locations during the three previous audits. In the three previous audits sound levels up to 55 dBA were consistently recorded at these locations. Therefore, the 5-10 decibel sound level reduction at these locations is a result of both the new barrier wall and the new transformer.

The southwest monitor location (i.e., Location 4) was sited near the switch gear, on the opposite side of the acoustic barrier wall from the transformer. As such, any noise generated here would not be appreciably shielded from the residences. During the autumn 2007 audit the sound levels on this side of the barrier were occasionally higher than on the transformer side of the barrier; sound levels of up to 70 dBA were recorded. During the winter audit, sound levels up to 54 dBA were recorded, except during known periods of higher winds. Disregarding periods of precipitation and onsite activity, both the spring and summer audits showed sound levels, at Location 4, typically less than 50 dBA. During this summer audit a sound level of 59 dBA


(averaged over a 10 minute interval) was recorded around 10:00am on August 17, 2008. This increased level of sound was only recorded once during periods of good weather and in the absence of known onsite activity. The measured sound levels at Location 4 were lower than those at Location 1 and Location 3 by approximately 2 – 5 decibels.

As suggested in the autumn 2007 report, the higher sound levels recorded on the switch side of the transformer wall, could have been attributed to corona noise on the existing 230 kV wires, the TS switch gear, insects, and/or the wind in the trees located on the nearby berm. The winter and spring acoustic audits provided no new insight into this anomaly. A sound level meter was again established at Location 11 during this audit and recorded sound levels very similar to those at Location 4; however, a sound level of 71 dBA (averaged over a 10 minute interval) was recorded at Location 11 August 17th around 7:00am. The peak sound levels at Location 4 and Location 11 occurred approximately 3 hours apart and differ in magnitude by approximately 10 decibels; therefore, they were likely not caused by the same source. During this time the sound level measurements at Location 3 (Location 1 lost power) were generally less than 50 dBA. The presence of corona noise cannot be clearly identified in any of the four seasonal audits. Therefore, the source of the higher sound levels recorded on the switch side of the transformer has not been specifically determined.

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 resident logs are summarized in Appendix F. This summer 2008 audit indicated that the residents typically noticed the TS noise when the background sound levels were low (i.e., less than 35 dBA), not when the overall sound levels, including all sounds at the receptor, were high. The residents often reported that the TS was audible when the L90 sound levels were less than 30 dBA, and therefore it was below the recordable gain range set on the sound level meters. In those cases the sound level has been marked on Figure 2 as 25 dBA to indicate that there was a concern reported at that time.

Figure 3 is a spectrogram of the unattended spectral measurements conducted at the southeast unattended measurement location (i.e., Location 3). The Figure confirms that the Leq 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. There are periods of increased sound at higher frequencies, particularly during the daytime and during the week. These increased sound levels are likely due to construction activities onsite.

Figure 4 integrates the record of the electrical power monitored at the wind plant to the TS sound level data shown in Figure 2. This figure does not show any meaningful correlation between electrical power and sound levels at the TS.


Figure 5 overlays the weather data on the sound levels near the transformer. During periods of higher wind speeds the monitors indicate higher sound levels. No obvious correlations with temperature or humidity exist with the monitored sound levels.

Unattended Acoustic Measurements – Residences

Figure 6a illustrates the LEQ unattended sound levels measured at the residences. The recorded sound levels vary significantly over time and are obviously influenced by wind and local activities (i.e., traffic), and include the sound of aircrafts, animals, and voices as well as any sound from the TS.

Figure 6b illustrates the L90 unattended sound levels measured at the residences. These sound levels show the steady source contributions. As shown on the Figure, the L90 sound levels are generally well below 35 dBA during night-time hours.

The data summarized in Figure 6a and 6b show that the night-time sound levels (i.e., when local activity is relatively low) at the residences are approaching 30 dBA on several occasions when the TS is producing noise. This indicates compliance with the MOE sound level limits during these times. The sound level range of the instruments was set to 30-110 dBA to ensure that they would not overload with any loud noises, this also meant they were unable to record sound levels less than 30 dBA.

Figure 7 adds the unattended measurement data from the TS to the unattended data at the residences. As shown, there is little correlation between the sound at Locations 1 and 3. This tends to suggest that while the sound levels at the residences are varying, the contribution of the transformer by itself was not a dominant contributor to the sound levels measured at the residences.

Figure 8 illustrates the sound levels at the residences against the recorded weather data. Local wind correlates closely with the measured sound levels, rather than with the TS sound levels. This correlation demonstrates that the wind is a key contributing source of noise at the residences.

The fact that the sound levels at the residences were not correlated with the sound levels at the TS, the fact that sound levels at the residences were often less than 30 dBA when the TS was operating and producing noise, and the fact that the sound levels at the residences seem to correlate closely with the wind speed rather than the TS noise, indicates that the sound contribution of the TS was in compliance with the MOE sound level limits during the measurement period.

Attended Acoustic Measurements – Transformer Station

Figure 9 illustrates the results of the measurements conducted simultaneously over a five minute period at three locations (i.e., Locations 8 through 10) around the TS, 30 to 40 metres from the


centre of the transformer. Location 9 is now shielded by the new acoustic barrier wall and Locations 8 and 10 are shielded by the original 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 acoustic reflections off of a large concrete retaining wall, and any further and Location 8 would have been behind an earthen berm (i.e., shielded from the transformer). Figure 9 represents the LEQ spectra of the five minute measurement. Unlike previous audits, which indicate a principal frequency of 400 Hz, this figure does not indicate tonal noise. This is likely due to either the addition of the east barrier wall around the transformer, the quieter sound levels of the replacement transformer, or both.

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

Figure 10 shows sound level spectra obtained by approximately doubling the distance between the instruments and the transformer (i.e., Locations 12, 13, and 14). The variations are the result of difference in location screening, refractions, and reflections from moment to moment as the microphones are swept.

Several Fast Fourier Transform (“FFT”) measurements were conducted at Location 9, approximately 40 metres from the transformer. These measurements are summarized in Figure 11, which illustrates the frequency makeup of the sound of the transformer in some detail. The sound is 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. The peak sound pressure level at 360 Hz is approximately 39 decibels. The frequency makeup of the transformer noise is similar to the previous transformer; however the sound levels are lower. The spring audit reported a peak sound pressure level of 49 decibels at 360 Hz, the winter audit reported a peak sound pressure level of 48 decibels at 360 Hz and the autumn audit reported a peak sound pressure level of 55 decibels at 360 Hz. This sound level reduction is a result of the new barrier wall, the new transformer or a combination of both.

Attended Acoustic Measurements – Residences

Attended measurements were also conducted at each of the residences 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 noise (i.e., 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

36 34 Resident dryer, crickets, animals, distant dog barking, TS not audible

August 12, 2008 21:30

33 28 Same as above < 20 < 20 Crickets, frogs August 14, 2008

03:35 21 20 TS barely audible 29 26 Bird noise

R01

August 15, 2005 16:00 33 32 Same as above

33 31 Crickets, distant traffic, frogs, some switch gear noise (crackle faintly audible)

36 33 Same as above, plus distant dog barking

August 12, 2008 21:50

34 33 Same as above 24 22 TS audible, some crackle August 14, 2008

03:55 23 22 Same as above

33 31 Switch gear audible, TS not audible

R02

August 15, 2008 16:20 30 28 Same as above

35 34 Distant dog barking, crickets, farm animals, TS not audible August 12, 2008

21:10 38 36 Same as above 24 21 Frogs, trees dripping, TS audible

R04 August 14, 2008

04:15 27 20 Same as above, plus sheep and goats


As shown in Table 3, the measured LEQ sound levels at the three receptors ranged from less than 20 dBA to 38 dBA and the L90 sound levels ranged from less than 20 dBA to 36 dBA. The measured LEQ 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, birds, talking, and wind-induced noises. As the measurements include the effect of these intermittent and extraneous sound sources, the measured L90 represents a better estimate of the steady sounds, including the noise from the TS.

As Table 3 indicates, the TS noise was only audible when L90 sound levels were below 33 dBA. This tends to indicate that TS noise is only audible when background noise is very low. This observation is consistent with previous audits.

In general, according to the attended measurements conducted and when the interference of background sound levels was minimal, the TS noise was generally audible when the L90 sound levels were between 20 and 22 dBA. Under similar conditions (i.e., when the TS was audible and background levels were low), the spring audit reported sound levels between 22 and 24 dBA, the winter audit reported sound levels between 29 and 31 dBA and the autumn audit reported sound levels between 31 and 33 dBA. These observations indicate that the new transformer is quieter; however it is difficult to determine the magnitude of the sound level reduction due to various seasonal and environmental changes between the four acoustic audits.

In an attempt to further quantify the contribution of the TS at the residences, a series of FFT measurements were made at two of the receptor locations (R02 and R04) when the transformer hum was audible. These measurements were made during the night of August 14, 2008 and they are summarized in Figure 12. Tones from the transformer were measured at 120 and 240 Hz at R02 and 120 and 480 Hz at R04, indicating transformer audibility at the receptors. However, the A-weighted levels were less than 20 dB and within criteria.

Summary and Conclusions

Similar to the conclusions reached in the three previous acoustic audits, the following conclusions are reached based upon the measurements conducted for the summer 2008 acoustic audit:

1) The measurements show no particular correlation between the sound levels at the residences and the sound levels near the transformer. It is noted that the sound levels 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 rather than the TS. These facts indicate that the contribution of the TS was in compliance with the applicable MOE sound level limits during the measurement period.

2) The comment logs of the residents’ observations during the four seasonal acoustic audits and the sound levels measured during the times of the observations indicate that the impact of the TS is often considered objectionable when background sound is low, indicating that the concerns


may be more related to audibility in a very quiet environment rather than to the absolute magnitude of the sound level impact. By itself, audibility does not indicate non-compliance with the MOE guidelines. The attended measurements conducted at the three receptor locations verify that the transformer is generally audible when the background sound levels are low. 3) Results obtained during the autumn 2007 audit indicated periods when the sound levels on the switch side of the acoustic barrier wall were occasionally higher than expected. The unexplained sound levels could have been attributable to the wind, insects, birds in the nearby trees, and/or corona noise. During the winter, spring and summer audits of 2008 an additional sound level meter was deployed on the switch side of the acoustic barrier to investigate this phenomenon. These three audits did not provide any new insight into the anomaly reported in the autumn 2007 audit and the presence of corona noise was not clearly identified. 4) There is evidence to suggest that the new Siemens TP-720 transformer is quieter than the previous GE Prolec transformer, although the replacement of the transformer has not eliminated the occasional audibility at the receptors. The sound levels measured in this summer 2008 acoustic audit have been compared to the results obtained in the three previous audits and both the attended and unattended measurements reported a sound level reduction. Specifically, the sound levels measured at Location 1 and Location 3 showed reduced sound levels by approximately 5 – 10 decibels and the FFT measurements conducted at Location 9 indicated a reduced peak sound level, at 360 Hz, by approximately 10 decibels. While these measurements indicate a sound level reduction, it is difficult to quantify the exact magnitude due to the simultaneous change in transformer and the addition to the barrier wall, the increased amount of onsite activity, in the form of construction and the fact that the audits have all been conducted during different seasons. The lab test results, from the manufacturer, confirm that the Siemens transformer is quieter than the original GE transformer.

Photo Plate 1: Part of the TS, showing acoustical barrier, Looking East

Photo Plate 2: Monitoring Location 1, Transformer Side of Acoustic Barrier, Looking South

Photo Plate 3: Monitoring Location 3, Transformer Side of Acoustic Barrier, Looking South

Photo Plate 4: Monitoring Location 4, Switch Side of Acoustic Barrier

Photo Plate 5: Monitoring Location 11, Switch Side of Acoustic Barrier

Figure 2: Overall LEQ Sound Level Data Collected Automatically within the Amaranth Transformer Station, August 2008, Plotted Against the Background (L90) Sound Levels

at the Receptors Corresponding to Comments from the Residents

20

30

40

50

60

70

80

90

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A]

Poor Weather Location 1 (Transformer Side) Location 3 (Transformer Side) Location 4 (Switch Side)

Location 11 (Berm) Location 5 (R01) Location 6 (R02) Location 7 (R04)

Aug

05,

18:

01

Aug

06,

4:0

1

Aug

06,

14:

01

Aug

07,

0:0

1

Aug

07,

10:

01

Aug

07,

20:

01

Aug

08,

6:0

1

Aug

08,

16:

01

Aug

09,

2:0

1

Aug

09,

12:

01

Aug

09,

22:

01

Aug

10,

8:0

1

Aug

10,

18:

01

Aug

11,

4:0

1

Aug

11,

14:

01

Aug

12,

0:0

1

Aug

12,

10:

01

Aug

12,

20:

01

Aug

13,

6:0

1

Aug

13,

16:

01

Aug

14,

2:0

1

Aug

14,

12:

01

Aug

14,

22:

01

Aug

15,

8:0

1

Aug

15,

18:

01

Aug

16,

4:0

1

Aug

16,

14:

01

Aug

17,

0:0

1

Aug

17,

10:

01

Aug

17,

20:

01

Aug

18,

6:0

1

6.3

16.0

40.0

100

250

630

1600

4000

10000

1/3

Oct

ave

Freq

uenc

y B

and

Figure 3: A-Weighted Spectrogram Measured at Location 3.10-minute Averaging Intervals

60-65

55-60

50-55

45-50

40-45

35-40

30-35

25-30

20-25

15-20

10-15

5-10

0-5

dBA

Figure 4: Overall LEQ Sound Level Data Collected Automatically at the Amaranth Transformer Station, With Electrical Power Data, August 2008

20

30

40

50

60

70

80

90

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A]

0

10

20

30

40

50

60

70

Win

d Fa

rm P

ower

Pro

duct

ion

[MW

]

Poor Weather Location 4 (Switch Side) Location 11 (Berm)Location 1 (Transformer Side) Location 3 (Transformer Side) Power Data from IESOPower Data from Canadian Hydro

Figure 5: Summary of Overall LEQ Sound Level Data Collected Automatically Within the Amaranth Transformer Station,

Plotted Against Meterological Data, August 2008

20

30

40

50

60

70

80

90

100

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A],

Hum

idity

[%]

0

5

10

15

20

25

Tem

pera

ture

[C],

Gro

und

Leve

l Win

d Sp

eed

[m/s

]

Poor Weather Location 4 (Switch Side) Location 11 (Berm) Location 1 (Transformer Side)Location 3 (Transformer Side) Humidity Precipitation TemperatureWind Direction Wind Speed

Figure 6a: Summary of Overall LEQ Sound Level Data Collected Automatically at the Residences, August 2008

20

30

40

50

60

70

80

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A]

Poor Weather Location 5 (R1) Location 6 (R2) Location 7 (R4)

Figure 6b: Summary of Overall L90 Sound Level Data Collected Automatically at the Residences, August 2008

20

30

40

50

60

70

80

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A]

Poor Weather Location 5 (R1) Location 6 (R2) Location 7 (R4)

Figure 7: Summary of LEQ Sound Level Data Collected Automatically at the Residences, With LEQ Sound Level Data at the Amaranth Transformer Station, Aug 2008

Overall sound levels include the effect of all sound sources including wind, vehicles, etc.

20

30

40

50

60

70

80

90

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A]

Poor Weather Location 5 (R1) Location 6 (R2)Location 7 (R4) Location 4 (Switch Side) Location 1 (Transformer Side)

Figure 8: Summary of Overall LEQ Sound Level Data Collected Automatically at the Residences, With Meterological Data, Aug 2008

Overall sound levels include the effect of all sound sources including wind, vehicles, animals, etc.

20

30

40

50

60

70

80

90

100

Tue,

Aug

05,

12:

00

Wed

, Aug

06,

00:

00

Wed

, Aug

06,

12:

00

Thu,

Aug

07,

00:

00

Thu,

Aug

07,

12:

00

Fri,

Aug

08, 0

0:00

Fri,

Aug

08, 1

2:00

Sat,

Aug

09, 0

0:00

Sat,

Aug

09, 1

2:00

Sun,

Aug

10,

00:

00

Sun,

Aug

10,

12:

00

Mon

, Aug

11,

00:

00

Mon

, Aug

11,

12:

00

Tue,

Aug

12,

00:

00

Tue,

Aug

12,

12:

00

Wed

, Aug

13,

00:

00

Wed

, Aug

13,

12:

00

Thu,

Aug

14,

00:

00

Thu,

Aug

14,

12:

00

Fri,

Aug

15, 0

0:00

Fri,

Aug

15, 1

2:00

Sat,

Aug

16, 0

0:00

Sat,

Aug

16, 1

2:00

Sun,

Aug

17,

00:

00

Sun,

Aug

17,

12:

00

Mon

, Aug

18,

00:

00

Mon

, Aug

18,

12:

00

Ove

rall

A-W

eigh

ted

Soun

d Pr

essu

re L

evel

[dB

A],

Hum

idity

[%]

0

4

8

12

16

20

24

28

32

Tem

pera

ture

[C],

Gro

und

Leve

l Win

d Sp

eed

[m/s

]

Poor Weather Location 5 (R1) Location 6 (R2) Location 7 (R4) Humidity Precipitation Temperature Wind Speed Wind Direction

Figure 9. Attended A-Weighted LEQ Sound Level Spectra Measured 30 to 40 metres from Transformer

Measurements Conducted August 12, 2008Wind Farm Producing Electricity

0

10

20

30

40

50

60

70

80

25

31.5 40 50 63 80 100

125

160

200

250

315

400

500

630

800

1000

1250

1600

2000

2500

3150

4000

5000

6300

8000

1000

0

Ove

rall

1/3 Octave Band Centre Frequency [Hz]

Soun

d Pr

essu

re L

evel

[dB

A]

Location 8 Location 9 Location 10

Figure 10: Attended A-Weighted LEQ Sound Level Spectra Measured 70 to 80 metres from Transformer

Measurements Conducted August 12, 2008

0

10

20

30

40

50

60

70

8025

31.5 40 50 63 80 100

125

160

200

250

315

400

500

630

800

1000

1250

1600

2000

2500

3150

4000

5000

6300

8000

1000

0

Ove

rall

1/3 Octave Band Centre Frequency [Hz]

Soun

d Pr

essu

re L

evel

[dB

A]

80 m East of Transformer 80 m South of Transformer 80 m North-West of Transformer

Figure 11: Discrete Frequency (FFT) Sound Spectra Measured at Location 9 Measurements Conducted August 15, 2008

10

20

30

40

50

60

70

80

0 50 100 150 200 250 300 350 400 450 500

Frequency [Hz]

Soun

d Pr

essu

re L

evel

[dB

]

Measurement 1 Measurement 2 Measurement 3

360 Hz, 39 dB

Figure 12: Discrete Frequency (FFT) Sound Spectra Measured at Location 9 and at Residences

Measurements Conducted When Transformer is Audible

10

20

30

40

50

60

70

80

0 50 100 150 200 250 300 350 400 450 500

Frequency [Hz]

Soun

d Pr

essu

re L

evel

[dB

]

Location 6 (R02) Location 7 (R04) Location 9 (TS)

Documents

Mr. Scott Hossie Canadian Hydro Developers, Inc. 34 ... Hydro...Mr. Scott Hossie Canadian Hydro Developers, Inc. 34 Harvard Road ... Manufacturer sound level test results for both