July 8, 2009 Mr. Bryan Tripp Canadian Hydro Developers, Inc. 34 Harvard Road Guelph, ON N1G 4V8 Re: Spring 2009 Acoustic Audit and Intermediate Verification Measurements Amaranth Transformer Station, Melancthon EcoPower Center Certificate of Approval (Air) Number 2233-6X9NBQ Dear Mr. Tripp, As requested, Howe Gastmeier Chapnik Limited (HGC Engineering) has undertaken an acoustic audit of the Amaranth Transformer Station (TS) associated with the Melancthon EcoPower Center. This audit represents the second of four seasonal acoustic audits that will be conducted to assess the impact of the TS noise, as a condition of amendment to the Certificate of Approval (Air) Number 2233-6X9NBQ issued October 17, 2007 by the Ministry of the Environment (MOE). Noise complaints were received from the residents during the measurement period; thereby, as per the Noise Management Protocol this acoustic audit also serves as the required Intermediate Verification Measurements. Four seasonal acoustic audits have been previously conducted, with measurements made in October 2007, February 2008, May 2008, August 2008, to assess the impact of the first of two planned 100 MVA transformers for the Melancthon I Wind Plant. The first three acoustic audits were conducted to assess the impact of a 100 MVA GE Prolec transformer. The GE transformer was replaced with a 100 MVA Siemens TP-720 transformer in June of 2008, and the summer 2008 acoustic audit was conducted to assess the impact of the new 100 MVA Siemens transformer. In addition, the acoustic barrier wall, which was originally open to the east side of the transformer, was extended on the east side, fully surrounding the transformer. This work had been completed prior to the summer 2008 acoustic audit. In October of 2008 the second of the planned Siemens TP-720 transformers was energized, as part of the Melancthon EcoPower Center (formerly Melancthon I Wind Plant and Melancthon II Wind
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 2 Plant). The new transformer is situated approximately 30 meters north of the first transformer. One seasonal audit has been completed to assess the impact of both transformers for the Melancthon EcoPower Center, with measurements made in January/February 2009. This current audit (spring 2009) is the second audit to assess the impact of the operation of both Siemens transformers. The results of the spring 2009 audit are summarized below: 1. The data recorded in the spring 2009 seasonal acoustic 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, including the appropriate penalty to account for the tonality associated with the transformers. This is consistent with the results of the previous acoustic audits. 2. The comment logs of the residents observations and the formal complaints filed during this seasonal acoustic audit and the sound levels measured during these times afforded a useful opportunity to directly assess the noise conditions which are considered objectionable. The measurements show that the noise levels considered objectionable by the residents are well within the MOE sound level limits. The spring 2009 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
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 3 1.0 Introduction This spring 2009 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 that there is 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 winter audits. Lastly, the measurement locations were modified to reflect the addition of the second transformer. This was outlined in a letter prepared by HGC Engineering, dated January 23, 2009 and is attached in Appendix C. 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 May 4 and May 13, 2009. 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.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 4 2.0 Background Certificate of Approval Air ( CofA ) Number 2233-6X9NBQ was issued for the Amaranth Transformer Station on October 17, 2007 by the Ministry of the Environment ( MOE ). This CofA required that Canadian Hydro undertake four seasonal, post-abatement acoustical measurements of the Amaranth TS. In this regard, Canadian Hydro retained HGC Engineering to independently carry out the measurements. Four seasonal acoustic audits were conducted in October 2007, February 2008, May 2008 and August 2008 to assess the impact of a single transformer associated with the Melancthon I Wind Plant. These audits can be viewed on the project website (www.melancthonwind.com). These reports should be read in conjunction with this report as they provide the background and basis for the measurements. Aercoustics Engineering Ltd. (Aercoustics) prepared an Acoustic Assessment Report ( AAR ), dated February 25, 2008 in support of an amendment to the Amaranth Transformer Station existing CofA, 2233-6X9NBQ. The AAR addresses several changes made to the Amaranth Transformer Station site. These changes include: replacing the 100 MVA GE Prolec transformer with a 100 MVA Siemens TP-720 transformer extending the barrier wall on the east side, fully enclosing the first transformer adding a second transformer to the site implementing a four sided acoustic barrier around the second transformer The first three acoustic audits (fall 2007, winter 2008 and spring 2008) were conducted to assess the impact of a 100 MVA GE Prolec transformer. The GE transformer was replaced with a 100 MVA Siemens TP-720 transformer. The summer 2008 acoustic audit was conducted to assess the impact of the new 100 MVA Siemens transformer. In addition, the acoustic barrier wall, which was originally open to the east side of the transformer, was extended on the east side, fully surrounding the transformer. This was completed prior to the summer 2008 acoustic audit. In October 2008 a second Siemens TP-720 transformer was energized. This new transformer is associated with the Melancthon II Wind Plant and is situated approximately 30 meters north of the first transformer. The amendment to the Certificate of Approval, 2233-6X9NBQ requires Canadian Hydro to undertake four additional seasonal acoustic audits to assess the impact of both the 100 MVA transformers. In this regard, Canadian Hydro has retained HGC Engineering to independently carry out the measurements. One seasonal audit has been completed to assess the impact of both transformers for the Melancthon EcoPower Center, with measurements made in January/February 2009. This spring 2009 acoustic audit represents the second of four seasonal acoustic audits which are part of the Amaranth Transformer Station and are associated with the Melancthon EcoPower Center (formerly Melancthon I Wind Plant and Melancthon II Wind Plant).
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 5 The five previous audits indicated that the Amaranth TS was operating in compliance with the applicable MOE sound level limits. Aercoustics prepared a Noise Complaint Management Protocol for Canadian Hydro Developers, Inc., dated March 14, 2008. This report was prepared at the request of Canadian Hydro to ensure that their facility continues to comply with all provincial standards and the conditions specified in the Certificate of Approval Air. This protocol defines a procedure for residents to raise their concerns regarding noise emissions from the transformer station and the actions required by Canadian Hydro to address their concerns. Official complaints regarding the acoustic emissions of the TS were reported prior to and during this seasonal audit. According to the Noise Complaint Management Protocol these complaints are to be addressed by this seasonal acoustic audit. The results will be discussed in Section 7.5, Resident Comment Logs and Registered Noise Complaints. 3.0 Site Description The TS is located on the east side of 10 th Line, south of 15 th Side Road, in Amaranth Township, County of Dufferin. There are two 100 MVA Siemens TP-720 transformers on the TS site, along with the supporting ancillary facilities. A drawing of the transformer, manufacturer s sound test results and a site plan showing the location of both transformers have been included in Appendix D. Figure 1A shows the TS in relation to the surrounding roads and residences, and Figure 1B illustrates the TS itself. 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). Table 1. Summary of Receptors. Resident Distance from ID Description Family Name Substation [m] R01 Kidd 214292 10 th Line northwest of TS 390 R02 Thompson 214242 10 th Line southwest of TS 360 R04 Whitworth 214215 10 th Line south of TS 490 4.0 Sound Level Limits As described in the autumn 2007 acoustic audit and based on the MOE s guideline NPC-232 Sound Level Limits for Stationary Sources in Class 3 Areas (Rural), after accounting for the
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 6 tonal character of the transformer sound, the applicable MOE sound level limits for the sound level contribution of the Amaranth TS at the receptors are: daytime (07:00 19:00 hrs): 40 dba evening (19:00 23:00 hrs): 35 dba night-time (23:00 07:00 hrs): 35 dba. These criteria apply to the Amaranth TS as a whole and have been updated to reflect the evening criteria. 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 25 to 30 dba or less 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 L EQ. 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. 5.0 Measurement Methodology The study is based on a complex collection of data series, obtained during the period from Monday, May 4 to Wednesday, May 13, 2009. 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. 5.1 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 May 4 th, 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 in Section 7.5: Resident Comment Logs and Registered Noise Complaints; Following the measurements, power production data was also acquired from the IESO and Canadian Hydro. The data are attached as Appendices F and G, respectively. It is noted that based upon HGC Engineering s review, the data obtained directly from Canadian Hydro agreed with the IESO data.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 7 5.2 Unattended Acoustic Measurements Eight unattended sound level meters were deployed and configured to record L EQ sound levels in 10-minute intervals. L 90 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 L EQ and L 90 measurements are included in Appendices H and I, respectively. Three sound level meters were deployed inside the TS fenceline, near the east fence and thus about 30 metres east of the centre of the transformers. These three locations are identified as Locations 2, 15 and 16 on Figure 1B and shown in Photo Plate 1. Three instruments were used in this area, rather than a single instrument, in order to provide some spatial averaging of the sound levels near the transformers. One sound level meter was placed on the southwest (switch side) of the acoustic barrier wall (Location 4), approximately 30 metres from the centre of the south transformer, monitoring noise from the switchgear (Photo Plate 2). Observations indicated that during the measurement period, the transformer audibility was low at this location. A sound level meter was also placed on the northwest (switch side) of the acoustic barrier wall (Location 17), approximately 30 metres from the centre of the north transformer (Photo Plate 3). This monitor was placed in the direction of R01, on the berm, primarily monitoring noise from the switchgear. Observations indicated that during the measurement period, the transformer audibility was low at this location. One sound level meter was also placed at each of the three residences described in Table 1. Locations were selected in conjunction with previous discussions with the residents, and were generally near the houses themselves, with little to no acoustic screening from the TS. The monitoring locations were consistent with those used in previous audits. 5.3 Attended Acoustic Measurements Attended measurements conducted over a series of one minute periods were made at the three receptors on May 4 th, May 6 th, May 8 th, May 11 th, May 12 th and May 13 th, 2009. 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 May 11 th. The measurements were conducted over a period of five minutes and they were intended to: investigate the spectrum of the noise radiated by the TS;
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 8 verify typical sound levels emitted by the TS and radiated in different directions; investigate propagation of sound with distance from the TS; Measurements were conducted simultaneously at three locations to the south, east, and northwest of the transformers at a distance of about 30 to 40 metres. These locations are identified in Figure 1B as Locations 8, 9 and 17, respectively. At this distance of 30 to 40 meters, 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. 6.0 Instrumentation MOE technical publication NPC-102, Instrumentation provides specifications for sound level measurement instrumentation. All equipment used in the Audit meets these requirements. 6.1 Unattended Acoustic Measurements Seven 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 Location 2 (Southeast) Bruel and Kjaer Type 2238 2342948 Location 4 (Southwest) Bruel and Kjaer Type 2236 1849429 Location 15 (Northeast) Bruel and Kjaer Type 2238 2562612 Location 16 (East) Larson Davis LxT 0001724 Location 17 (Northwest) Bruel and Kjaer Type 2238 2562611 Location 5 (R01) Bruel and Kjaer Type 2238 2448501 Location 6 (R02) Bruel and Kjaer Type 2236 2039554 Location 7 (R04) Bruel and Kjaer Type 2236 2151071 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
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 9 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 eight 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 E. 6.2 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. 7.0 Assessment and Discussion 7.1 Unattended Acoustic Measurements Transformer Station Figure 2 shows the sound levels measured at four points around the transformers. Three sound level meters were located on the east side of the transformers, within the fenced area, at Locations 2, 15 and 16. The sound level monitor at Location 16 lost power on May 7, 2009 for a period of about 6 hours, resulting in no recorded data during this period. One sound level meter was located on the southwest side of the south transformer at Location 4. This location was selected to be in the direction of R02 and is consistent with previous audits. A fifth sound level meter was located on the northwest side of the north transformer at Location 17. This location was selected to be in the direction of R01. Measurements at Location 2 are extremely variable, typically less than 50 dba. There are several analogous periods where the sound level is steady on the order of 55 dba. The source of this
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 10 steady sound level is unknown; however this steady sound does not affect the sound levels recorded at the other meters surrounding the transformers. Sound level monitors at Locations 15 and 16 were located similar distances from the transformer and separated by a distance of approximately 15 m, as shown on Figure 1b, which confirms that the sound source was very local and did not have a widespread impact. Sound level measurements at Location 15 and 16 show sound levels typically between 35 and 50 dba during the measurement period. 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 15 and 16 during this spring 2009 acoustic audit are generally less than the sound levels recorded on the east side of the transformers during the first three acoustic audits, and comparable to the levels recorded during the most recent two audits (summer 2008 and winter 2009). Specifically, in the first three seasonal acoustic audits (October 2007, February 2008 and May 2008) sound levels on the order of 50 to 55 dba were consistently recorded on the east side of the transformer. Reduced sound levels, typically between 35 and 50 dba, were recorded during the summer 2008 audit. This 5-10 dba sound level reduction on the east side of the transformer which was a result of both the new barrier wall and the replacement transformer installed in the spring of 2008. The southwest monitor location (i.e., Location 4) was sited near the switch gear associated with the south transformer, about 30 m southwest of the center of the south transformer. Any noise 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. This phenomenon was investigated in the three seasonal audits that followed and the phenomenon was not repeated in any of the subsequent audits. The source of the higher sound levels was not specifically determined. During this spring 2009 acoustic audit, the magnitude of the measured sound levels at Location 4 was generally consistent with those measured at Locations 15 and 16. Sound levels on the order of 35 to 45 were generally recorded under favorable weather conditions. The northwest monitor location (i.e. Location 17) was sited near the switch gear associated with the north transformer, about 30 m northwest of the center of the north transformer. Due to site geometry, the location was on top of the perimeter berm. Any noise here would not be appreciably shielded from the residence. During this spring 2009 acoustic audit, the magnitude of the measured sound levels at Location 17 was generally consistent with those measured at the other locations within the transformer station; however, there are several periods that indicate increased sound levels. These increases typically occur during periods of increased wind speeds or during the daytime when the sound level could have been impacted by any number of local sound sources, (i.e., traffic, onsite activities, including; Hydro One maintenance, Canadian Hydro transformer maintenance, etc.).
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 11 Figure 2 also shows the background (L 90 ) sound levels recorded by the unattended sound level meters at the residences at times corresponding with the time of day noted in the residents observation logs. The L 90 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 residents logs are summarized below in Section 7.5; Resident Comment Logs and Registered Noise Complaints. Figure 3a is a spectrogram of the unattended spectral measurements conducted at the east unattended measurement location (i.e., Location 16). The Figure confirms that the L eq sound levels vary with time, but that there are consistently peaks in particular A-weighted frequency bands (i.e., 125, 250 and 500 Hz), representing a relatively steady sound source. The magnitude of the overall sound level changes with background sound, particularly with varying wind and weather conditions. These variations are also shown in this Figure. Figure 3b represents the same measurement location (Location 16), but the instrument was temporarily reconfigured for greater temporal resolution for this time period (8:15 to 9:33 on May 11, 2009). Figure 3c represents the same measurement location (Location 16), but the instrument was returned to 10-minute logging intervals. These figures indicate a similar conclusion to Figure 3a; the dominant A-weighted frequency bands are relatively steady when the influence of background sound was low. Figure 4 integrates the record of the electrical power monitored at the wind plant to the TS sound level data shown in Figure 2. The power production varied throughout the measurement period. There were many instances where power production was low and several instances where power production was high. During this audit period a correlation between the measured sound levels and power production was not found. Figure 4 shows a few periods where the sound levels increased with a corresponding increase in power production, likely a result of the increased wind speeds. This phenomenon was not consistent. Therefore, Figure 4 does not show a consistent correlation between electrical power production and the measured sound levels at the transformer station. 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. There is a close correlation between the ground level wind speeds and the measured sound levels at the transformer station. No obvious correlations with temperature or humidity exist with the monitored sound levels. 7.2 Unattended Acoustic Measurements Residences Figures 6a, 6b and 6c illustrate the L EQ unattended sound levels measured at the residences and the appropriate sound level criteria for the sound level contribution of the transformers. 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 sound from the TS. Figures 6a, 6b and 6c show a number of instances when the L EQ sound levels are below the sound
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 12 level limits during both the daytime and night-time hours when the transformers were operating. This is particularly true at night because the influence of local activity is relatively low. The MOE sound level limits apply only to the sound level contribution from the TS, therefore the L 90 sound level is often a better descriptor of the sound level contribution of a steady sound source than the L EQ sound level. Figures 6d, 6e and 6f illustrate the L 90 unattended sound levels measured at the residences and the appropriate sound level criteria for the sound level contribution of the transformers. The L 90 sound levels exclude infrequent noise sources (i.e. car passbys, aircrafts, etc. although they include ambient noises of longer duration such as wind and rain). As shown on Figures 6d, 6e and 6f, the L 90 sound levels are generally well below 35 dba during night-time hours and 40 dba during daytime hours when the TS is operating and steadily producing noise, indicating compliance with the MOE sound level limits during these times. Sound levels at R04 (the Whitworth Residence) were often higher than the sound levels recorded at the other residences during the same time period. From site observations, the sound levels recorded at this location are known to include additional background sound due to the surrounding trees and resident farm animals. Figures 7a, 7b and 7c compare the unattended L EQ measurement data from the TS to the unattended L EQ data at the residences and Figures 7d, 7e and 7f compare the unattended L EQ measurement data from the TS to the unattended L 90 data at the residences. There is little consistent correlation between the recorded sound levels at the receptors and at the TS. This tends to suggest that while the sound levels at the residences are varying, the contribution of the transformers by themselves was not a dominant contributor to the sound levels measured at the residences. As shown in Figures 6d, 6e and 6f, there were a number of occasions when the L 90 sound levels were significantly higher than the MOE sound level criteria. These increased sound levels generally occurred during the daytime when the influence of local activity is more frequent. Increased sound levels of this nature are not unexpected, particularly when monitoring for an extended period of time at a residential location. As shown on Figures 7a through 7f the sporadic increases in sound levels at the receptors do not correlate with the sound levels recorded at the TS. Therefore, it can be concluded that the sound level spikes measured at the receptors were influenced by local sound sources and are not representative of noise from the TS. Figures 8a, 8b and 8c illustrate the L EQ sound levels at the residences against the recorded weather data and Figures 8d, 8e and 8f illustrate the L 90 sound levels at the residences against the recorded weather data. Measured sound levels correlate closely with local wind rather than 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
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 13 with the wind speed rather than the TS noise indicate that the sound contribution of the TS was in compliance with the MOE sound level limits during the measurement period. 7.3 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, 9 and 17) around the TS, 30 to 40 metres from the centre of the transformers. These positions are consistent with the winter 2009 acoustic audit. 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 L EQ spectra of the five minute measurement. This figure indicates tonal noise at all of the measurement locations, with a principal frequency of 125 Hz. The magnitude of this tone is comparable to the measurements conducted for the winter 2009 acoustic audit. 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 18). In general, the sound levels decreased due to the increasing separation from the transformers. The figure indicates tonal noise with a principal frequency of 125 Hz, particularly at Location 13. A Fast Fourier Transform ( FFT ) measurement was conducted at Location 19, approximately 40 metres from the centerline of the transformers. These measurements are summarized in Figure 11, which illustrates the frequency makeup of the sound of the transformers in some detail. The sound is tonal with peaks at 120, 240, 360 and 480 Hz, with other harmonics present. The peak sound pressure level at 120 Hz was approximately 48 decibels for the first measurement and 44 decibels for the second measurement. The FFT measurements of the transformers indicate a frequency profile that is typical for electrical transformers. Transformer noise is typically tonal at the electrical frequency of 60 Hz and harmonics of this frequency. The FFT measurements conducted in the Summer 2008 acoustic audit, the Winter 2009 acoustic audit and this Spring 2009 acoustic audit indicate that the peak sound pressure level is present at 120 Hz, whereas the previous acoustic audits (conducted for the GE transformer) indicated a peak sound pressure level at 360 Hz. 7.4 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
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 14 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 L EQ [dba] May 4, 2009 R01 L 90 [dba] Criteria [dba] 41 37 40 10:15 37 29 40 May 6, 2009 33 30 35 01:00 33 31 35 May 6, 2009 10:45 31 23 38 31 May 8, 2009 44 39 40 17:45 32 32 40 May 11, 2009 36 30 40 10:00 30 26 40 May 12, 2009 32 32 35 22:15 33 32 35 May 13, 2009 36 32 35 6:15 35 31 35 HGC Engineering Site Observations Distant traffic, birds, TS not audible Frogs, birds, transformer hum is clearly audible, airplane overhead 40 Birds, insects, horses, TS not audible 40 Distant traffic, birds, insects, TS not audible Birds dominant, distant traffic, wind, TS not audible Birds, distant traffic, TS not audible TS audible and dominant, frogs Birds, goose, distant traffic dominant, TS faintly audible
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 15 Location Date and Time L EQ [dba] May 4, 2009 R02 R04 L 90 [dba] Criteria [dba] 29 22 40 12:00 32 23 40 May 6, 2009 43 38 35 00:30 45 42 35 May 6, 2009 10:15 32 23 40 33 24 40 May 8, 2009 42 32 40 17:15 42 31 40 May 11, 2009 32 29 40 10:20 36 30 40 May 12, 2009 39 31 35 22:05 40 37 35 May 13, 2009 6:00 36 32 35 36 32 35 May 4, 2009 37 30 40 12:15 36 39 40 May 6, 2009 48 46 35 01:15 48 46 35 May 6, 2009 36 32 40 11:00 35 27 40 May 8, 2009 39 33 40 18:00 38 34 40 May 11, 2009 38 27 40 10:30 34 28 40 May 12, 2009 38 30 35 21:45 39 31 35 May 13, 2009 41 35 35 5:40 43 36 35 HGC Engineering Site Observations TS faintly audible, birds Birds and frogs dominant, distant traffic TS barely audible, birds, distant dog TS faintly audible, birds, plane overhead, distant car Wind noise, birds, TS not audible, distant traffic Birds, distant aircraft, TS not audible Birds, frogs, distant traffic, TS not audible, light wind Goose dominant, birds, distant traffic, TS not audible Goose dominant, birds, distant traffic, TS faintly audible Distant voices, distant traffic, birds, TS not audible Frogs dominant, distant dog, distant traffic, TS not audible Birds, frogs, distant traffic, TS not audible Birds dominant, wind in trees, distant dog, distant traffic, TS not audible Birds, insects, distant traffic, TS not audible Frogs, insects, birds, distant traffic, TS not audible Distant traffic, farm animals, birds, TS not audible
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 16 As shown in Table 3, the measured L EQ sound levels at the three receptors ranged from less than 29 dba to 48 dba and the L 90 sound levels ranged from less than 22 dba to 46 dba. The measured L EQ 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 L 90 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 the L 90 sound levels were 32 dba or less. This tends to indicate that TS noise is only audible when background noise is very low and below MOE guidelines. This observation is consistent with previous audits. Influence of the Second Transformer at the Residences This audit (spring 2009) was the second to be conducted with both transformers energized. During this audit the transformers were, at times, audible to some degree. During this investigation, the L 90 sound levels were less than 32 dba during periods of transformer audibility. The most recent audit (winter 2009) was also conducted with both transformers energized. During the winter 2009 audit, attended measurements conducted during periods of transformer audibility at the residences showed L 90 sound levels less than 23 dba. The summer 2008 audit was conducted for 1-Siemens transformer. During the summer 2008 audit, attended measurements conducted during periods of transformer audibility at the residences showed the L 90 sound levels between 20 and 22 dba. The first three audits (fall 2007, winter 2008 and spring 2008) were conducted for the original GE transformer. During these audits, attended measurements conducted during periods of transformer audibility at the residences showed L 90 sound levels between 22 and 33 dba. Theoretically, the addition of the second transformer should have increased the sound levels at the residences by up to 3 decibels; however, the variability associated with the measurements due to various environmental and seasonal factors is more than 3 decibels, which makes it difficult to determine the magnitude of the sound level changes due to the addition of the second transformer. Regardless, the measured sound levels remain well within the MOE sound level limits with both transformers operational. In an attempt to further quantify the sound level contribution of the TS at the residences, a series of FFT measurements were made at the three receptor locations when the transformer hum was audible. These measurements were made during the early morning of May 13 th at R01, the night of May 6, 2009 at R02 and the day of May 6, 2009 at R04. The measurements are summarized in Figure 13. Tones from the transformer were measured at 120 and 240 Hz at the receptors, confirming transformer audibility at the residences. The tones were less pronounced at R04 because the background sound was dominant at this residence during all of the attended measurements included in this audit.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 17 7.5 Resident Comment Logs and Registered Noise Complaints The residents have provided their comments for the measurement period. These comment logs have been included in Tables 5 through 7 below. Additionally, several official complaints were registered with Canadian Hydro during the measurement period from the residents at R01 (Kidd) and R04 (Whitworth). Table 4 summarizes the dates and times that the noise complaints were received by Canadian Hydro from the neighbouring residences. This table also indicates the resident that filed the complaint, the corresponding L EQ and L 90 sound levels recorded by the automatic monitors at the time of the complaint, and the weather conditions recorded by the ground level weather station situated at R02. Table 4: Summary of Official Complaints Received during the Measurement Period Date and Time Receptor L EQ at Receptor [dba] L 90 at Receptor [dba] Ground Level Wind Speed [m/s] May 5, 2009, 8:50 Whitworth 39 30 2 m/s, E Ted Whitworth sent an email reporting that the transformer was loud last night and this morning May 10, 2009, 7:40 Kidd 43 35 5.5 m/s, NW This is Theresa Kidd calling it is Sunday the 10 th of May it is approx. 7:40 and I am calling obviously with issues with the transformer substation. I am going to go ahead and call the after hours emergency number. I don t have an emergency at this point it s the same old, same old. However, the transformer has been clearly audible for the last hour and I will notify your technicians and hopefully they can get here shortly so they can hear exactly what we are hearing. As shown on Table 4, the measured L 90 sound levels were less than or equal to 35 dba at the time of both registered complaints. This further indicates that the TS continues to be in compliance with the MOE sound level limits and residents concerns continue to be related to audibility and not to the absolute magnitude of the sound. Tables 5 through 7 summarize the dates and times that the residents have noted the sound from the transformer station to be audible or perceptible inside or outside of their homes. These tables also include the corresponding L EQ and L 90 sound levels recorded by the automatic monitors at the time noted on the log, the weather conditions recorded by the ground level weather station situated at R02 and the text noted in the comments themselves.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 18 Spring 2009 Acoustic Audit and Interim Verification Measurements DRAFT: June 26, 2009 Table 5: Summary of Unattended Sound Level Measurements during times when the Residents of R01 (Kidd Residence) have noted the Transformer Station to be Audible or Perceptible Inside or Outside of their Homes) Date and Time May 4, 2009 19:00 19:30 L EQ at Receptor [dba] L 90 at Receptor [dba] Ground Level Wind Speed [m/s] Precipitation Resident Comments 40-43 < 30-31 2 m/s, N The evening is calm and crisp; it is approximately 5 degrees, sunny, blue sky. No noise outside; soft chiming throughout the house. I did note that there were quite a few turbines not running this evening. May 5, 2009 5:40 May 5, 2009 6:30 May 5, 2009 7:50 49 31 2 m/s, ENE Transformer is quite audible this morning. The morning is clear with a blue sky. Slight air movement from the east. Slight chiming outside. House is quieter; both house and barn are chiming slightly. 48 35 2 m/s, ENE Transformer continues to be audible. 48 35 2 m/s, E Transformer is no longer audible; house continues to chime and bathroom floor is vibrating slightly. May 5, 2009 40-51 32-39 3 6 m/s, SE Didn t notice transformer; house has been chiming softly all 17:30 21:00 evening. May 6, 2009 45 33 0 m/s Not feeling great when I arrived home this morning. Threw up Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 19 5:45 on the side of the road. Low fog expected things to be louder than they were can hear transformer. House is alive high pitch ringing floors vibrating slightly but I wasn t wearing my running shoes. I lay down for awhile; I awoke with a massive headache and called in sick to work; I know I can t stay here went to my sister s in Orangeville. Janelle has been ill for over two weeks she saw the doctor last Friday next time I ll take her to emergency at the hospital. May 7, 2009 8:30 May 8, 2009 7:30 May 9, 2009 7:15 7:45 43 31 0 m/s Arrived home at 8:30 a.m. I can hear high pitch tones inside and outside of the house as well as in the barn. Transformer not audible. 47 34 3 m/s, SW Too much traffic to hear what transformer was doing; inside, house is ringing and the floors are vibrating slightly. The morning is damp. 44 46 32-36 2 m/s, SE Arrived at 7:15 a.m. this morning. Transformer audible air is heavy but it is not raining yet. Feel pressure in ears while outside. Transformer remained audible to 7:45 a.m. House is noisy ringing outside too. May 9, 2009 47 37 1.5 m/s, SSE 10:15 Rain Vibrations in floor were noticeable by 10:15 a.m. It has rained a lot since we arrived home. Neck is numb while outside checking on four horses in the run. May 9, 2009 41 38 7 m/s, NW Noise in house was evident until leaving for the evening at 20:30 8:30 p.m. Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 20 May 10, 2009 43 37 4.5 m/s, WNW Happy Mother s Day! Arrived home at approximately 6:30 6:55 a.m. Didn t notice transformer until outside at 6:55 a.m. Transformer is audible while standing on the deck. Air is damp at approximately 4 degrees with moderate cold west wind. Ears blocked after seconds of being outside if I can hear the transformer over all nature s noises why can t HGC hear all the ringing tones outside too? May 10, 2009 46 40 4.5 m/s, WNW Our house is very noisy today; at 7:05 a.m. a light mist has 7:05 blown over and my ears are still blocked inside the house. There is a high pitch tone not ringing constant not pulsing no floor vibration in kitchen transformer remains audible. May 10, 2009 42 53 37-41 5.5 m/s, NW Reported to Cdn Hydro however I called both lines (issues and 8:35 9:30 emergency); spoke with Scott who told me he would send someone around; the transformer noise was not evident when returning from chores at 8:35 a.m. but it is clearly now ringing throughout the house and continued through to 9:30 a.m. when we left our property. May 11, 2009 5:15 May 11, 2009 20:30 21:00 33 24 0 m/s Terry arrived this morning at 5:15 a.m. it was cold out, approx. 0 degrees, crisp with a light frost on the ground. Calm morning. The transformer was audible. 40 42 26 28 2 m/s, NW Our house is another story. Vibrations throughout and loud ringing. My left ear hurt earlier. At almost 9:00 p.m. the chairs inside and outside are vibrating. While sitting outside on the deck at 8:30 p.m., I can feel waves pulsing through my chest. I Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 21 May 12, 2009 7:00 7:15 May 12, 2009 17:30 20:30 May 12, 2009 22:20 May 13, 2009 3:30 May 13, 2009 5:30 May 13, 2009 7:30 had to go in. This evening, while doing chores in the barn, I noticed while standing in the cement manger that it was also vibrating many times over. 42 44 30-31 1 m/s, NW I arrived home at approximately 7 a.m. Transformer was audible though it was low. The pressure on your head was quite acute - noted for minimum 15 minutes. Light frost, clear blue sky, no noticeable wind. 39 52 26 34 0 2 m/s, W 5:30 p.m. 8:30 p.m. While outside, experience neck numbing and pins and needles in upper back and shoulder area. Pressure on head was also evident. 49 29 3 m/s, S At 10:20 p.m. the transformer was audible low Megan took measurements. We had the neighbours in tonight, haven t seen them for months; after being in the house for five or ten minutes, Ron mentioned he could hear ringing but Kim, his spouse, couldn t though she could feel pressure on her head. 29 21 2 m/s, SE Transformer is loud 47 34 1 m/s, SE Transformer is audible though not as loud as it was at 3:30 a.m. 46 34 2 m/s, SE Transformer is audible. House is quite bad this morning. Terry slept in the house tonight and identified two sounds or tones; 1 ringing (high pitch) and one lower pitch drone.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 22 Table 6: Summary of Unattended Sound Level Measurements during times when the Residents of R02 (Thompson Residence) have noted the Transformer Station to be Audible or Perceptible Inside or Outside of their Homes) Date and Time May 4, 2009 22:00 May 5, 2009 6:00 May 5, 2009 22:00 May 7, 2009 22:00 May 8, 2009 6:30 May 8, 2009 22:00 L EQ at Receptor [dba] L 90 at Receptor [dba] Ground Level Wind Speed [m/s] Preciptiation 33 31 1.5 m/s, NE TS is audible 35 29 3 m/s, ENE TS is audible 40 39 2 m/s, ESE TS is audible 36 33 3 m/s, WSW TS is audible 43 31 3 m/s, SW TS is audible 36 35 1.5 m/s, SW TS is audible Resident Comments
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 23 May 9, 2009 37 30 4.5 m/s, ESE TS is audible 6:00 May 10, 2009 7:00 May 11, 2009 6:00 May 11, 2009 22:00 May 12, 2009 6:00 May 12, 2009 22:00 43 34 4 m/s, WNW TS is audible 47 32 0 m/s TS is audible 24 32 1 m/s, NW TS is audible 48 32 0 m/s TS is audible 37 24 2 m/s, SSE TS is audible Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 24 Table 7: Summary of Unattended Sound Level Measurements during times when the Residents of R04 (Whitworth Residence) have noted the Transformer Station to be Audible or Perceptible Inside or Outside of their Homes) Date and Time May 4, 2009 12:00 May 4, 2009 21:20 May 5, 2009 2:15 May 5, 2009 4:10 May 5, 2009 5:00 May 5, 2009 7:30 May 5, 2009 13:50 May 5, 2009 22:00 L EQ at Receptor [dba] L 90 at Receptor [dba] Ground Level Wind Speed [m/s] Precipitation Resident Comments 36 31 4 m/s, ENE Monitors arrived at 12 noon, sunny, bright, breezy day, warm weather, transformer slightly audible over the sound of the wind, birds, animals, etc. Noise heard throughout the afternoon. 49 48 1.5 m/s, NE 9:20 p.m. buzz heard inside and outside the house 42 < 30 2 m/s, E Buzz in house at 2:15 a.m 43 < 30 2 m/s, E Roaring at 4:10 a.m 43 33 2 m/s, ENE 45 34 2 m/s, ENE 48 R01 49 R04 32 R01 35 R04 Rumbling/vibration at 5 a.m. and onward inside the house still ongoing at 7:30 a.m. 3.5 m/s, SSE Away in morning, returned at 1:50, still buzzing weather warm, sunny 64 F, checked Theresa & Terry Kidd's pregnant mare, Loud vibration and pressure in the air there, it gave me a terrible headache and I was only there for 5 minutes 48 46 2 m/s, ESE 10 p.m. temp 48 F clear, still, bright night, frogs singing, but transformer buzz is still quite audible over these sounds I feel pressure on my ears, both inside and outside the house
May 6, 2009 3:50 May 6, 2009 5:00 May 6, 2009 7:55 May 6, 2009 13:45 Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 25 43 31 1 m/s, E Awakened at 3:50 a.m. by a buzz and vibration in the house 43 30 0.5 m/s, E 49 36 1 m/s, ESE 40 R01 44 R04 <30 R01 <30 R04 May 6, 2009 44 43 2 m/s, SSE 22:25 Rain 5 a.m. temp is 40 F, weather is misty and cool, an audible low hum is still ongoing at 7:55 a.m 3.5 m/s, S Away in morning, returned at l:45 and went to Kidd's to check their horse--there was a strong feeling of vibration and transmission as soon as I stepped out of car, it could also be felt in the barn temp 65 F, warm and sunny, returned home, our house is buzzing and humming Away at other farm during evening, returned home at 10:25, our house is roaring May 7, 2009 52 49 1 m/s, NE 4 a.m. rumbling in house, 50 F and raining 4:00 Busy for rest of day and did not make notes May 8, 2009 2:00 43 34 2 m/s, SSW Rain May 8, 2009 5:00 47 34 1 m/s, SSW Roaring heard in house throughout the night, from 2 a.m. onward, 5 a.m. temp is 50 F and it is raining May 8, 2009 49 46 0 m/s Loud roaring at 10:20 temp is 60 F, sunny Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
22:20 May 9, 2009 00:00 May 9, 2009 00:30 May 9, 2009 2:45 Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 26 47 42 2 m/s, S Still roaring at midnight 46 42 2 m/s, SSW 46 40 0.5 m/s, SW Heard humming and roaring inside throughout the night, noticed at 12:30a.m., 2:45a.m, 4:00 a.m. etc. May 9, 2009 4:00 45 35 1.5 m/s, N May 9, 2009 48 46 5.5 m/s, WNW Same noise throughout the day, still going at 11 p.m. 23:00 May 11, 2009 1:45 May 11, 2009 5:30 May 11, 2009 21:30 May 11, 2009 22:30 < 30 < 30 2 m/s, N 1:45 a.m. 30 F, clear and still, low buzz outside, pressure on ears inside 48 35 0 m/s Distinct buzz outside at 5:30 a.m. 43 38 2 m/s, NW 36 < 30 1 m/s, NW Away during day, low buzz inside and out at 9:30, 10:30 p.m. temp is 40 F. clear and still Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 27 May 12, 2009 5:00 May 12. 2009 7:25 May 12, 2009 13:30 May 12, 2009 22:30 May 13, 2009 5:00 31 < 30 0 m/s 5 a.m. temp 30 F, frost on ground, usual buzz inside and out 51 35 2 m/s, NW Still roaring at 7:25 42 R01 51 R04 31 R01 <30 R04 3 m/s, N Checking mare at Kidds, 1:30 p.m.--distinct buzz and pressure heavy on ears in barn 35 30 3 m/s, S 10:30 p.m. roaring in house as usual 44 33 3 m/s, SE 5 a.m. loud roaring in house, temp 40 F
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 28 Spring 2009 Acoustic Audit and Interim Verification Measurements DRAFT: June 26, 2009 As shown in Tables 5 through 7, the measured L EQ sound levels at the three receptors ranged from less than 30 to 53 dba and the L 90 sound levels ranged from less than 20 dba to 49 dba. Several time periods have been shaded grey to indicate that the wind speeds were greater than 15 km/hr (4.2 m/s); which is used as a threshold for measuring low sound levels according to the MOE s technical publication NPC-102. Several time periods were also shaded grey to indicate precipitation. Sound levels recorded during these periods are not representative of the steady source sound level associated with the transformer station. During periods of appropriate weather, the L 90 sound levels were generally less than 35 dba during periods of audibility, with seven exceptions at R04 (the Whitworth residence). The L 90 sound levels measured at the other two residences (R01 and R02) during these time periods were always less than 35 dba. Consequently these increased sound levels are likely due to local activity at R04. To further support this conclusion the sound levels recorded at the transformer station did not indicate any evidence of elevated sound levels during these time periods. During these seven time periods of interest, the L 90 sound levels recorded at Location 4 and Location 2 (the closest monitoring locations to R04 at the TS) were on the order of 40 dba. Considering the distance setback of R04 from the TS, sound levels on the order of 40 dba measured near the TS would be significantly less than 30 dba at R04. As shown on Figure 2 these elevated sound levels are often greater than the sound levels recorded at the transformer station. The analysis of the recorded sound levels in conjunction with the residents comments is consistent with previous audits and confirms that the impact of the TS is in continual compliance with the MOE sound level limits even during complaints. 8.0 Summary and Conclusions 1) The measurements show no consistent 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 are 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 during the measurement period the contribution of the TS was in compliance with the applicable MOE sound level limits, which account for the tonality associated with the transformer. 2) The comment logs of the residents observations and official noise complaints logged during this seasonal acoustic audit 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. Audibility does not indicate non-compliance with the MOE guidelines. The attended measurements conducted at the three receptor locations verify that the transformer is in compliance with the applicable MOE sound level limits but can be audible when the background sound levels are low.
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 29 Photo Plate 1: Monitoring Locations 2, 15 and 16, East Side of Transformers, Looking North
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 30 Photo Plate 2: Monitoring Location 4, Southwest Side of the South Transformer, Looking West
Canadian Hydro Developers, Inc., Amaranth Transformer Station Page 31 Photo Plate 3: Monitoring Location 17, Northwest Side of the North Transformer, Looking North