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HomeMy WebLinkAbout81 - 25 PLANNING COMMISION MINUTES & AGENDAS MARCH 10, 1982 9 OF 9Tables Hand 17 show the data frorri two TV sets an the Calaveras s3dcz, Fripm an investigation of the Mariposa facility lV1ATY lyl'e,ad.,End, no izzapul, sive electrical interference was visible. However, the �yi.negard, proam li, ler may be overdriving the Jerrold amplifier,; A, 6 dB pad was found can; the amplifier input, Another 10 dB pad-was added and the gain, of the amplifier was adjusted for a better picture quality. A switch on the amplifier. was found in the separate mode which should have b'eA,n in the combined xr,od-e, In general, the Sierra Correctional Facility MATV system is in a location that experiences light to mc„lerate electrical interference with respect to seasonal changes, This location alr,o experiences a fade in the signal path during the early evening and it is further aggravated by having the existing system, :not Optimized. 'fable 18 shows the predicted power line noise field strengths expected at the existing Calaveras head end antennae. The proposed 230 kV line is approximately 1, 100 feet from the Calaveras antennae. The predicted noise field strengths at this distance for fair weather conditions are expected to be below the 1vL4TV system internal noise. However, under foul weather con- ditions and with the existing MATY equipment, it is possible that the low band VFIF, mainly channel 3, might be slightly degraded, Table .19 illustrates that only tuider foul weather conditions will the proposed. 230 kV transmission. line introduce a noise level about equivalent to the SCC NLA.TV internal noise, otherwise it is lower than t:�e internal noise. J-22 PLATE 35 GAY,,AVERA.S MATY */ SYSTEM 37 TV Sets RCA Preamp Jerrold Amply RGA Finca 80 Series l OG -z05 2300A - Modal Color Spectrum /FM Antenna Gain dB Gain 38 d8 NF—,/6 dB TR956 WTV assumed NF 15 dB Modal 71-89"0 Gann ... lea Jerrold Splitter© L,ow, VHF + 6 dB roterred to o. Model 1592 3, dB 159s High VHF +10 dB Folded UHF +11 dB Dipole MARIPOSA MATY SYSTEM same as above�.o. W egard Jerrold Ampl. SPreamp "°°"'" Model 2661 -�—aame as above DA 825 A Gain 25 dB Gain 45 dB NF 11 - 12 dB assumed NF 7 dB Master Antenna Television System Noise Figure SCHEMATIC EMATI (COURTESY P,G,BE,) PLATE 34 FM Mobile Radio Desetasing vs J,jt�jral l'r4,f le for a 23.0 kV 'Transmisslo %Inc 2:0 l5 a� .n U 0 A 10 [C�Q' q Q N 4I A 5 O -r 10 b .-a „y � 0 4 I.Y� I��IP fly �wY '°'""°^-•...e... ' threshold of effect _ foal hee vy rain (. 47 inch/hr, -5 light rain 230 kV 230 1,.v fair 230 kV -10 ..0. 100. 200 300 400 500 600 Lateral Distance Feet 700 $00 (COURTESY P.G,&E.) California. The system is composed of approximately 250 base radio stations;, 3, 5010 mobiles,, and 520 pack sets operating in the 4$, 150 and 450 MHz,2V bands. All of the manned transmission substations operating at voltages up to and a.ncludxng 500 kV are equipped with base radio stations operating in the .150 MHz band. one 50Q kV substation is also equipped with a 4$ Mliz base.. These radio systems ars; vital: to the operation of the eleo- trical system and arc'used primarily for the restoration of service in all kinds of weather. Qver a period of many years, the 150 MHz radio stations operating in this severe electriQaI environment have nOL experienced any adverse effect detrimental to the operation of the stati()n Even the 48 MHz station, although more susceptible to electric interaerkxace, performs satis- factorily under adverse weather conditions. With regard to television reception at the Sierra Conservation, Center, it was investigated and, determined that the SCC" has an MATV system with two separate head ends and associated equipment. (See Plate 35. ) From a field investigation, it appears that the system was originally designed for reception of only the Sacramento channels. In addition., the system; appears to have several deficiencies. The orientation of the Calaveras Head End antenna did not appear to be optimized, which results in a reduced radio frequency (RF), level presented to the preamplifier; The distribution ampli- fier currently used is approximately 8 dB low in gain within the low band spectrum and also contributes a high noise figure to channel 13. The observed picture quality ranged from light to heavy electrical interference. It is felt that the heavy interference was caused by a local source due to it beingcyclic in nature. A possible cause is an air conditioning unit or refrigeration equipment, */ Megahertz J-21 tj trN 1 1 1 1,111 f h � �>"'�"wrs ii, r• Kdz � ✓ � i �� dl �� ' ti r �m C� �•'` 40 2 SIV a y 1 lAIOti114YK1�91�'�' aeQmMun icatQr Tra "sm'[i%r w kwa w+ rrti •�. � K>,.Id t . t,. Calaveras Head,, Encs. R8lop T «%%``__ 4� wY.t r r*..��•...r.'�fe+w.r�ywe�....r.....r'(` �1 �f�W iN OM«fNd Ofl� ., e.«.,... M 17A Lely ;y..ai1 v r Jf Sierra " k j r+� Tuf(CaGh ��CP.j�ler 'sur ^, ,r�u >� .`•� �" VIM �� f,�,n.,� f t"al+"'�"41l't'�'�% "'� � .tib.. `t- '1 ,:.« t '+...,�.. a;�,.d,. `•�.. w >,.,,Y., _ e � .�• �1 �!' " - � � � t ( N 1• ' � "� n'• fit\ � ,}I'; '1, A"w , 5,,,%`r .' }F,.i #'}- ^W '> ic�{wc�1.ti� l` G."4,% ^. "'• 1r .f.�r'y,.-�` .,.� r'°1 �4.•. C7 �n' i riw�'S.~F{�-C It6tA",.t"a F{1 Yt'�""`p�h.�-a1�.'gi �.Yv-�... oz K>' : ^'' l -' .,r, �.i, �'�., r..^`, rd � `v, \� �. l \ 1 7 \I S-#•�L�/..z�+;. � '" .. ii1 = 2000` �' .'l. "� ,,,~'•...�\ AZ `� kart , �, t..,y ,'; �� - - PLATE 33 : SIERRA CONSERVATION !CENTER The Sierra Conservation Center is l,or,4ted 11 mikes west of aonora# Tuoluznlyo County, It is a nediuzn-minimuYx� security institution enoornpassing 301 4gros of land and is de9igned to accommodate 1, 200 inmates and over 400 staff, Ino mates have .free mobility within the institution in order that they may have the use of dayrooms, sleeping living rooms, educational classes, vocational train i.ng, recreational activities and other facilities.The physical plant is ;a single And double story structure of reinforced concrete, cons tructioa Platte 33 shows the general planlayout of the existing i1. 15 lY t,ransmission line and the Sierra Conservation Center property along theyro l posed 230 kV trans, missW line, The proposed 230 kV transmission line will be approxi mately 1, 100 feet from, the nearest part of the main correctional facility, Therefore, radio reception, either AM broadcast or FM, should not have any impact at this distance. (See pages d$-11,) Two-way radio cbmh unicacion is also a vital tool at the prison in the, event of escapes, emergencies, etc, The area used fortwo-.way communications is from the watch towers to the top of the mountain and beyond as well as in. the SCC property„ Previous tests conducted upon narrow band FM receivers have shown that under fair weather conditions the SCC should not experience any receiver degradation, The two-way receiver should be able to receive and transmit where they now can receive or transmit. However, under foul weather conditions the two-way radio portable receiver might range from 21 dB desensi.ng directly under the proposed line to no degradation approxi mately 150 feet beyond the proposed line. (See Plate 34 for details, ) Only under foul weather conditions, 'and when attempting to receive a message under or immediately adjacent to the proposed line, might there be an impact. It should also be noted that PGandE operates an extensive mobile radio system throughout its operating area, which is about two-thirds of the State of J-20 TABLE 16 Calavaras MATV System, Dorm 4 TV Set Video carrier Channel Level (riBmy— 1 3 +10 6 +5 10 1.2 13 Observed Picture Cualit Very light to Occa,siz.at-._jr��oder,ate electrical ,joxsc, amcar, ghoA2s Good viewable b'icture, color slightly wlshocl c,ut, but probably due to TV act, Color beat, smear on edge, Ghostingo smear, picture noiac VlitY not adgood Picture, except for smear, E)Octrical andbm,noise, difficult to distinguish, Light to moderate electrical novice, smear, Noticeably noisie3,, UtLg 17 C41avaraa MATV System, I)orim 22 TV Set Video Carrier Baseband SN.'�; ,.Channel, Levr dllmv poise (di3myl dB 3 .� "46 58 6 +16 +11 13 +8 »40 X86 X40 ;% milivalt '% Signal to hbise Vatic X23 Observed„_Plcturz ac lit Slightisnow unci smear; impulsive electrical noise, extremely randoin and cyclic, 3 to 4 minute cycle, very Moderate to heavy in intensity, ghost- ing; beat appears to be adjacent channel intermodulation product caused by sot, Good Picturaminor well displaced ghost, smear) Well displaced minor level negative video contrast, very `Aoderate electrical equipment cycling through, Smear, extremely light, vei`y ,xando n. electrical noise. Smear, occabtonal light flashes, Table 18 POWERLINE NOISE FIELD STRENGT14S EXPECTED AT THE EXISTING CALAVERAS HEAD END ANTENNAE (Units are dB µy/mrt/tor a 3 MHt±f/ Bandwidth) Channel Fair Weather Foul Weather w/o 230 kV vv/230 V r/o 2'30 It V% w/230 kV 2 14.33 - 9.19 1.67 6.81 3 -14.83 9.69 1 17 6.31 6 -17.33 -12.19 -1.33 3. 81 10 -24.33 -19.19 -8: 33 -3.19 13 25.33 -20.19 -9.33 -4.19 Table 19 CAVERAS MATV I ' SYSrEM POWER LINE AND MATV SYSTEM THERMAL NOISE EVALUATION Power Line Thermal Noise Resultant Nome TV Noise. Voltage. Volta e g L Level. TV Amplifier Amplifier Output Carrier Carrier -System Carrier -internal Noise Channel,. Output Levels Internal Noise + Pwr. Line Noise Ratio dB'f ��— Fair Foul dg },�V dB fsV dB µV. Ratio dB- Fair Foul, d8' 3' 48.55 &1.. 55 b3„ 9 Fair-- Foul'. 42.35 58..35 62_ 9` o4 67.25, 1.13.5 62.94 49.6 49.5 46.-"5 1p' 32.95 49.35 65.9 6:4..2 1�q. 5 65_9; 46.6 46.56 45.3' 35.8'5 51,- S5 69. � 65.99 109.5 69F. 91 43.613 43, 6 43.51 69..97' 106.5 36.6 36.6. 36.53 ATV -Master Antenna. Television System UV -microvolts Electrostatic and glectroma uetic Occasional, annoying, non -:hazardous electrical sensations may be exrgri- enced by persons touching ungrounded metal objects on or adjacent to tie edge of transmission line right-of-way. These ungrounded metal objects sometimes acquire an electrical potential by electrostatic coupling, Typical types of ungrounded objects include wire fences having dry wood Posts, vehicles with rubber tires, and wooden barns with large metal roofs. The sensation experienced may range from the slightest g perceptible t=ingle to s distinct; sensation, Grounding of the fence or other metal objects will eliminate the induced electrostatic potential and any sen- sation that might be experienced by touching the object, A 60 hertz current of 1 milliampere (ma) can be perceived by 50 percent of the population and this value is commonly known as the 'threshold of per- ception level." Currents of a level, (in the range of 1 to g 5 ma) which may be painful, but which will not cause Toss of muscular control are termed secondary shock currents, Currents g cater than 5 ma are considered pri- Mary shock currents (that is, they do cause logo of muscular control). The magnitude of the electrostatic vol'.age induced on ungrounded metal objects which ate in the field of the 230 kV transmission line would depend on the surface area of the object, the distance of tate metal sur- .faue from the transmission line conductor, and the height of the object -above ground, The magnitude of the current one could eXperence would depend on the transmission line voltage, the site and shape of the object,, and the :impedance of the current's path through the person touching the Object to the ground. The latter varies greatly according to the indi-, vidual and the nwhhtt in which the person is grounded, The short-circuit discharge current from an insulated Tench five feel thigh 1 and approximately 2;400 feet long parallel to a 230 kV transmission line at the point of m4ximunl pickup (i.e,, approximately five feet horizontal dis- tance from the outer conductor) is 5 ma. Msximum short-circuit Brom an automobile on a 230 k'V transmission line right -of. -way is In the order of 0.4 ma and .from a very large 'truck 12 feet by 12 feet by 50 ,fent long is on the order of 1.4 oma, plate 36 shows a lateral profile of the electrostatic j-26 ` 1.-8 cf Q) . 1. 1.2. �a A 0.8 ._ . . F 0'.4 0. 0 0 40 8"0' I20 150 200 feet Horizontal Distance From The Transmission Center Line Electrostatically Induced Short Circuit Discharge. Current Profile: to a. Large Truck fora Typical 230 kV Single- Conductor Two Circuit Transmi5sio Line O: c M �. M s» 01, discharge current from a large truck vorsus hart-1,0111'al digtp center line of tile trans,. Ince J�Jlle -n IssiOn line. The discharge current decro,-ts(-,q rapidly as the object is Moved away front the tower In sllvnrnary, secondary shocks maY'Occur in rare instances when farm or Construction equipinent or extremely large veh:cles operate on Or adjacent the right-of-way. Electric L�a�a n0tic Field An overhead high voltage AC Power line produces both (IlecLA*ic and magnetic fields. To assess the effects Of such fiolds, t"cY Must be described quanti- tatively in Whia (kilovolts Per me'Ler) for the electric field and in tho 'magnetic field. Gauss for Th . e electric field gradic!nt profile for a typical double (,irctijt# SL.31e conduc- tot) 280 kV transmission line is illustrated in Plate 37, The maximurn electric fied , "' for the t'1ifoot height Of Measureme-nt p)i t Is kV/m. Correspondingly, in approvimatel, te 38, the 1-naVMeLic field Profile for a typical 230 kNr double circuit single Conductor line is i�enctxatocllu fo., an assumed loading; of 525 amperes (one I -1!al£ the bA'1nm,,r exncx rating), The maximuxn magnetic f, '01d at a height of five approxitnately 0. 048 Cac18s, fUet abuve 6r-)11nd is Public concern has arisen ov(sr Possible biological effects Produced by power transmis I (:t a of the ('10ctrlt fields siOn lines. The ElectI I contracted %-ith the IIT Researeb Institute to criti r'c Power Research Institute literature and on-going resa earch nd 1 to cally '"vieW the world-wide search, The rerulLing report entitled Identify areas Occtding additional re- search, field 13'0109'cal t�ffccts of 111gh Voltage ('IT Ae"arch In,st1tute, 1975), is based oil review of J-27 �. 0.0 0 20 40, &0 80. 100120 110' feet Distance From. Transmission bine Center Line n O r c rn r- .r Electric Field. Gradient Profile: for a Typical 230 kV Single. Conductor Two Circuit Transmission Line. 0.0 0 20 40, &0 80. 100120 110' feet Distance From. Transmission bine Center Line n O r c rn r- .r Electric Field. Gradient Profile: for a Typical 230 kV Single. Conductor Two Circuit Transmission Line. a bn 0. I o m6 5 foot Leight. of measurement point 0.04 0.02 0.00 a 20 40 60 80 100; 120 140 160 feet Distance From Transmission Line Center Line O c M M G m.00 Magn&ti= Field Pr.-fl"ile for a. Typical 230 kV Single Conductor Two Gircuit Transmissio.t. Dine Carrying One -Half the -Summer Emergency Rating, or 525 Amperes approximately 800 U.S. and foreign papers pertaining to biological effects of electric fields at powerline frequencies. Gradients from powerlines are comparable to natural and other man-made electric fields. Beneath thunderclouds, electric fields of 3 kV/rn,.or more have, been measured. I)t,-st storms in northern -west Africa can reverse the earth's 0. 13 kV/m field (caused by the Ionosphere) and produce fields up to 1.5 kV/m. Examples of man-made electric fields are those from electric blankets (0;25 kV/m), boilers (0.13 kV/m), stereos (0.09 kV/m), and electric ranges (0.004 kV/m). (Values are all at distances of about one foot. ) (IIT Research Institute, 1975). The generally accessable magnetic field produced by transmission lines is much less than the magnetic fields which now occur in homes or industrial environments due to appliances and machinery. Soldering guns and hair dryers can getierate 10-25 Gauss in their vicinity and a can opener, kitchen range, and electric shaver generate 5-10 Gauss. The earth's natural mag- netic field is about 0, 5 Gauss. (IIT Research Institute, 1915). A summary of the studies as reported in EPRI report on "Biological Effects of )figh Voltage Electric Fields" follows: A. HVAC Field Influences on 1411maft-q No significant differences between test subjects and test controls were observed according to seven references relevant to studies conducted in Western Europe and thu United States. At the very high electric field intensities - on the order of 100 kflovOlt8 Pei' meter (some 50 times the normal field intensities at ground level for 230 kV transmission lines), some transition after effects have been noted. Jm28 i As reported by Soviet research workers, persons occupationally exposer to high voltage electric fields in the complex environment found in switchyards have complained of a number of disorders such as headaches, fatigue and nausea. A major problem exists in interpreting these findings because of the difficulty in deteritiining which factors in this unique environment were responsible for the observed symptoms. The Soviets report that the small arc self -discharge is another factor which might be responsible for. the symptoms. ,Another plausible factor, unique to the switchyard environment, is the very high level 100 Hz accoustical noise arising from magneto striction in the transformer, Such high level: 100 Hz accoustical noise can cause similar symptoms. B. HVAC Field Influences on Animals No hazardous effects on laboratory and agricultural animals have been attributed to electric field exposures according to references from Western Europe and the United States. However, some of the results obtained are not definitive owing to possible problems with the biological protocol or dosimetry: C. Horizontal. Power Freguencv Electric and Magnetic r, leld Effects on a Variety of Test Subjects The horizontal, portion of the electric field and the rnagtretic field are s. a ',o the field which would be created by the Navy,s proposed ELF (4 -Iz) Comj-Aunicati6, s System (Project Saaguine or Seafarer), D',.) hazardous effects have Yc; beet, identified in some 45 studies coridt cted under Project Sanguine. he subjects of the tests included soil anthro' pods; earth worms, fish, marine animals, tadr.o es, rodents, pigeons, monkeys; man, atnooebas, and plants (including pine trees). Some -29 lfauffman and 1vlic,haeolson (1974) present several conclusions as follows; Research to date has failed to provide any convixtcitig evidence that human exposure to stationary or low frequency electric fields has any harmful biological effect. "Until such evidence is found, the obvious dangers of electrical spsrking should determine the limits of safe human expost;tre. Wilson 1974 states: It seems, that the p11ysxo100c;a1 research on the influence of electric magnetic energy has identified few tangible effects. For the most part, the cxpc4M011L ,.l effort lacks a syotematic approach to the examination of the critical variables involved and parametric studies are the exception rather th:4n the rule: Part of the difficulty probaLly lies in the fact that the research. accomplished so far has not Produced data suggesting than 0 p,r-�found physiological hazard might be developing, Tilis, in t• .rn, Piinits the interest in this field of study by those searching for P.nd rlap,d developments, Research into biological effects of both electric and magnetic fields is being continued. Such re=search is difficult and mu$t be care flIlly (jone to Uncover any subtle effocts: After criticalty reviewing the litoraWre )ncGrnitig known biological effects of power frequency electric fielda on man and aajmals; no Convincing .evidence is reported that 50/60 hertz elrrwtric fields, as nort-nalXy encotr�lt red, can cause: a significant biological effect to humans, �Yhere a possible effect is suggested, its cause can be attributed to factors other than clettric fields such, as different enviren#neontal influenr,.08 or improper biological procedures: ITAl REFERENCES 1. Reiter, R. "Effects of Atmospheric and Extra -Terrestrial Electromag- netic and Corpuscular Radiations on Living Organisms, It Sixth Interna` tional Journal of B.Lometeorolo y, Vol. 17,, No. 3, Pages 2------------- 17-227. 2. Schmitt, O. H. , and Tucker,. R. D. rrHnman Perception Strength Low Frequency Magnetic Fields It IEEE ` of Moderate ' iy1 C.+ S zlx O s 1t1I17 Record, New York, Pages 65-70, June 1973.- 3. Kaufman, G. E. , and Michaelson, S. M. rr Critical Review of Effects of Electric and Magnetic Fields, It From Biologic nd the is logical Effects of Low -Frequency Magnetic asci Ele Sancectric and Fields, Llaurado as, Pub1. C. C. Thomas, Springfield, U. S. A. Pages 49-61, 1974. d. Fields Wilson, tr Arthur S. "Physiological Effects of Magnetic and. Electric From $iologic and Clinical Effects of Lovv Freauency 7Vlaenetic and Electric Fields , Llatirado and Sances, publ. C. C. Thomas, `— Springfield, U S. A. , pages 71-80 1974, "Y' 7-32 ,I APPENDIX K METRIC ChNVERSrON To Conversion From Me tr ic, Factor �--- --- -- 1�nfi1 i:alt biil. MLllimetre Owl) 0.0254 2.54 Length g Lncl (in) Centimetre (em) 0.305 Toot (ft) Metre (M) (v) 0.914 Yard (yd) Metre l�ilometre (km) 1.61 Mile (mi) Area cmi9l) Xilocircul'F Square blillimetr� (mm2) q (an) 0.625 0.094 t (ft Square 'Foot (ft) Square Metres tlecte,re (ha) 0,4 • Acre (ac) Square bJile (mit) Square Kilametrd (ktit2) 2«6 Volume Cubic Foot Ut3) Cubic Mete (m3) •, 0,028 3.8 Gallon (gala Litt Cubic Me. Ind) 077 Cubic Yard (yd') Wei =h,t �' Pound (lb) Kilogram ft) is 'ion (t) 0.45 0.9 Tonblear K (kwh) Tera Jo EnetgY .lowatthour