S06-SoundTutorial

AUDIBLE SOUND REGULATORY REQUIREMENTS FROM A UTILITY PERSPECTIVE

JANE ANN VERNER P.E. MARCH 2006

Overview 

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F a ct c t o r s T h a t D et et e r m i n e A cc c c e p t a b l e So S o u n d L ev ev e l s Ba ck g r o u n d I n f o r m a t i o n Z o n i n g Re q u i r e m e n t s P r o j e ct c t S p e ci c i f i c Fa Fa ct c t o r s To To H e l p M ee e e t Zo Z o n i n g Re Re q u i r e m e n t s

Factors That Determine Acceptable Sound Levels 

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P r o x i m i t y o f su su b st at i on o r t r a n s f o r m er t o s lee p in g f a c cii l i t i e s, s, ei t h er c o m m er ci al o r r esi d en t i al Zo n i n g o r u s e o f l a n d s e l ev ev e ls  I n d u s t r i a l h i g h e r n o i se permitted Ti m e o f d a y o r n i g h t f o r s o u n d activity Dur at ion, volum e and n at ur e of so u n d s u ch a s t o n e , f r e q u e n c y an d b r o ad b a n d

Background Theory 

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Pe r i o d - Ti m e t h a t i t t a k e s f o r o n e v i b r a t i o n c y c l e ( T se c) Fr e q u e n c y # o f v i b r a t i o n c y c l es p e r se c ( f H z) F = 1/ T 5 0 0 H z = 1 / 0 .0 0 2 se c

Background Theory  

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Pu r e To n e s j u st o n e Fr e q u e n c y N o i s e – co n t a i n s m a n y frequencies Tr a n s f o r m e r s So u n d s  Co r e , w i n d i n g s & co o l i n g  Co r e n o i s e 1 2 0 H z & e v e n harmonics H u m a n A u d i b l e Ra n g e  2 0 H z t o 2 0 ,0 0 0 H z  2 0 H z t o 1 6 ,0 0 0 H z

Sound Chart

Background Theory 

A w e i g h t e d So u n d s – si m u l at e s t h e f r e q u e n c y r e sp o n s e o f t h e h u m an ear . Ad j u st ed p ri m ar i l y f o r l o w f r e q u e n c i es.

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Se e C5 7 .1 2 .9 0

Ta b l e s 9 & 1 0

A Weighted Sound Curve

Perception of Sound Intensity Ch a n g e i n d B 1 dB 3 dB 5 dB 10 dB

H u m a n Pe r ce p t i o n I m p e r ce p t i b l e Ju s t N o t i ce a b l e Cl e a r l y N o t i ce a b l e Su b s t a n t i a l Ch a n g e

Requirements 

M o st Co m m o n  7 A M t o 7 PM 6 5 d b A  7 PM t o 7 A M 5 5 d b A

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So m e ar e a s m o r e s t r i n g e n t  Li m i t o f 1 0 d e ci b e l s o v e r e x i s t i n g so u n d l ev e l s

Requirements PHI NJ (Con’t) Continuous sound level limited to 50 dbA

Hz 3 1 .5 63 125 250 500 1000 2000 4000 8000

dB 96 82 74 67 63 60 57 55 53

Project Specific Factors Screening and Landscaping

Project Specific Factors  

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B a se l i n e so u n d m e a su r e m e n t s Gr e e n f i e l d si t e - M ea su r e a t si m i l a r s i t e To u r f o r z o n i n g p e r s o n n e l I n c l u d e so u n d l i m i t i n y o u r s p ec Sp e ci f y l o w s o u n d e m i t t i n g equipment Se t b a c k s I EEE C5 7 .1 3 6 A n n e x B

Calculating Transformer Noise Level with Setback from Property Line Step 1: Determine Transformer Sound Power Level (Lw) Lw = LpIEEE + 10 log10 (Surface Area) (B1) Where: Lw = Transformer Sound Power Level (dBA) LpIEEE = Transformer Sound Pressure Level at IEEE Locations (dBA) Surface Area = IEEE Measurement Surface Area in m2 = 1.25 x Transformer Height x Measurement Perimeter (B2)

Calculating Transformer Noise Level with Setback from Property Line Step 2: Calculate Sound Pressure Level at a Specific Location Assuming hemispherical sound wave radiation LpR = Lw – 10 Log10 (2πR²) (B3) Where: LpR = Sound Pressure Level at the Specified Distance, R (dBA) Lw = Transformer Sound Power Level (dBA) R = Distance from Transformer to Location in m. This resulting Lp calculated from Step 2 will provide an estimate for a single transformer installation.

Calculating Transformer Noise Level with Setback from Property Line The maximum allowed sound level at a property line is 53 dBA. The property line is 122 meters from the transformer. The height of the transformer is 6.1 meters and the perimeter is 18.3 meters. What should the maximum allowable sound pressure level of the transformer be at the IEEE locations? LpR = 53 dBA, R = 122 m, h = 6.1 m, p = 18.3 m Using equation (B2) Surface Area = 1.25 x h x p = 1.25x (6.1 m) x (18.3 m) = 139.5 m2 Rewriting equation (B3) Lw = LpR + 10 log10 (2πR2) Lw = 53 dBA + 10 log10 (2 π(1222)) = 102.7 dBA ⇒ Using equation (B1) Lw= LpIEEE + 10 log10 (Surface Area) LpIEEE = 102.7 dBA – 10 log10 (139.5) = 81.3 ⇒ dBA The maximum allowable sound pressure level of the transformer at the IEEE locations is 81 dBA.

Summation of Levels of Multiple Sources # o f I d e n t ica l So u r ce s

2 3 4 5

d B ad d ed t o single level 3 5 6 7

dB dB dB dB

Tutorial Session IEEE Transformer Committee

Ramsis Girgis

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Transformer Noise Sources & Characteristics

Monday, March 20, 2006

Topics

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Sources / Components of transformer noise

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Characteristics of each noise component

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Relative magnitudes of no-load and load noise

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Is Load Noise an issue?

Sources of Noise in a Transformer 

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No-Load Noise 

Core Noise

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Cooling Equipment Noise

Load Noise

Total Noise = No-Load Noise + Load Noise    3     r   e   m   r   o    f   s   n   a   r    T   r   e   w   o    P    A    B    B    B    A    ©

   4     r   e   m   r   o    f   s   n   a   r    T   r   e   w   o    P    A    B    B    B    A    ©

 s  e  c  r  u  o  S  &  m  u   r  t  c  e  p  S  y  c  n  e  u  q   e  r  F

Core Noise 

Caused by Magnetostriction of core material 

Mainly 120 Hz, 240 Hz, and 360 Hz with some 480 Hz 

100, 200, 300, and 400 Hz for 50 Hz operation

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Relative magnitudes are determined by core material & flux density

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An unexpectedly high level of a frequency component would indicate core / tank resonance

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Frequency Spectrum of Core Noise - 1 80

70

   B    d  ,    l    e    v    e    l    e    r    u    s    s    e    r    p    d    n    u    o    S    6     r   e   m   r   o    f   s   n   a   r    T   r   e   w   o    P    A    B    B    B    A    ©

60

50

40

30

20

10    5  .    2    1   5    3

   0    0    3    0    0    5    0    0    0    5    0    0    0    0    0    0    0    0    0    0    0    0    5    0    0    0    0    0    0    0    0    0    0    0    0    0   4    5    6    8    1    0    1    2    1    6    2    0    2    5    3    1   4    0    5    0    6    3    8    0    0    0    2    5    0    5    0    0    0    0    0    6    2    0    2    5    3    1   4    0    5    0    6    3    8    0    0    1    1    1    0    1    2    1    6    2    0    1

Frequency, Hz

Frequency Spectrum of Core Noise - 2 90 80    )    B    d    (    e    r    u    s    s    e    r    P    d    n    u    o     S

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70 60 50 40 30 20 10 0    5    5  .    2    1    3

   0    0 4    5

   3    8    0    6

   0    0   0    3   0    0   0    0    0    0   0    1    2   5    1    6   0    2    0   0    2    5   0    3    1   5    4    0    1    5    6    8    1    0

Frequency (Hz)

Cooling Equipment Noise 

Caused by Fans and Pumps 

Moderate levels of low-frequency ( 2,000 MW M W per mile2

D e n s e U r b a n En En v i r o n m e n t

3

T y p i c a l 1 3 8/1 3 k V Su b s t a t i o n Syn Bus Syn Bus Breakers

138/13 kV

65 MVA

Circuit Switcher

Transformer Breakers

To Network Load

Syn Bus

H i s t o ri c a l T ra ns f or m e r N o i s e Requirement  

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New York City Noise Code – Octave band noise specification with annoyance criteria Locate substations in commercial zones next to major roads Industry standards: transformer no -load and cooling no-load equipment (pumps & fans) noise

Isolated areas: 65 – 85 db(A) Urban areas: 60 - 65 db(A) Residential: Main tank in enclosed room with radiators in ventilated area

T y p i c a l Su bs t a t i o n A r e a 1 9 7 0s

Co m m e rc i a l – Re s i de nt i a l Z on e

5 T r a ns f o r m e r V a u l t s I n -L i n e

T r an s f o r m e r L o a d N o i s e Fi e l d Me a s u r em e n t s  

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Survey: 6 transformers from 4 different manufacturers Power Loading: 30 -50 % of nameplate rating 30-50 Voltage: 105 % of nameplate rating

68 – 78 db(A)

M a n h a t t a n Su b s t a t i o n De s i gn Co n c ept nc

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Midtown Manhattan Mixed residential and commercial Limestone veneer, granite base Louvers lit to appear as storefront Planters in sidewalk

10

N Y Ci t y M 1 R N o i s e Pe r fo r m a n c e Re q u i r e m e n t (So u n d Pr e s s u r e L e v e l ) Manufacturing Zone Octave Band Freq. (Hz)

Maximum Average Sound Level (db)

20 - 75

79

75 - 150

74

150 - 300

66

300 - 600

59

600 - 1,200

53

1,200 – 2,400

47

2,400 – 4,800

41

Above 4,800

39

T ra nss m i s s i o n Sys r an Sy s t e m V o l t a ge ge Re qu i re m e nt s (Ov e re x c i t a t i o n ) Voltage Class (kV)

138

345

Voltage Limits (kV)

Duration

Range

Lower

(minutes)

Over 160

-

0

153153-160

-

10

146146-152

124

30

130130-145

130

Continuous

Over 400

-

0

381381-400

-

10

363363-380

311

30

328328-362

328

Continuous

T y p i c a l A r ea St a t i o n N o rrm m al Op e r at i n g Co n di t i o n  

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140 -145 kV HV bus voltage 140-145 Non -summer loading: Four transformers loaded Non-summer to approximately 30 % of nameplate rating (65.3 MVA) Summer loading: Four transformers loaded to approximately 80 - 90 % of nameplate rating (65.3 MVA) NLTC: 125.4 kV position LTC: 12L position (12.558 kV position) Power factor: 0.93

T y p i c a l A r ea St a t i o n Co nt i n g e n c y Op e rra att i n g Co n di d it i o n    

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138 -140 kV HV bus voltage 138-140 Summer loading: Three transformers loaded to approximately 143 % of nameplate rating (65.3 MVA): 93.8 MVA for 8 -hours 8-hours NLTC: 125.4 kV position LTC: 16R position (15.468 kV position) Power factor: 0.93

L ow N o i s e T r an s f o r m e r De s i g n s a ns

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65 MVA, 132 -13.8 kV Transformer 132-13.8 93 MVA, 132 -27 kV Transformer 132-27 65 MVA, 132/65 -13.8 kV Transformer 132/65-13.8 234 MVA, 138 kV +/  +/-- 25 25°° Phase Angle Regulator * 234 MVA, 335 -136-13.8 kV Auto-transformer Auto -transformer * 335-136-13.8 420 MVA, 335 -136-13.8 kV Auto -transformer 335-136-13.8 Auto-transformer 150 MVAr, 345 kV Shunt Reactor (Future) * New designs for 2007 -08 2007-08

Re v i s e d 2 0 0 5 N Y C N o i s e Co d e

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New law provides for maximum sound levels measured, with the windows open, within a residence in either a mixed use or residential use, or within a commercial building.

Co m p a r i s o n o f N Y C Z R v s . N Y C N o i s e Co d e L i m i t s (So u n d Pr e s s u r e ) 80    )    B    d    (    l   e   v   e    L    d   n   u   o    S

70 60 50 40 30 31.5

63

125 500 1000 Octave Band Frequency (Hz)

2000

4000

8000

ZR Property line M1R

ZR Property line M1

Des ign Lim it outside res idential

Design Limit outside com mercial