BSTJ 10: 2. April 1931: Status of Joint Development and Research on Noise Frequency Induction. (Wills, H.L.; Blackwell, O.B.)

12.9 MB·English

Status of Jolat Development and Research on Nolze
Frequoacy Induction *

‘By HL, WILLS and 0. BLACKWELL

Ee a bee Homers mis treqaney ection
Bt viol tnsha any lel seen

2, Saaceptivoeen,fasine hie
|. Coupling fect ‘nic comcers che nteltion of ower and
“The pane ctr tho vate floc i etal wad describes the work
‘lh cmon aa engage eee een
secre of ube ot tc te i Hua a ek

Us chica of the

MIL Joint Subcommitise on Development and Research ie the

‘cney thonugh whieh Ue National Electr Light, Asextation
tind the ell Telephone System carryout technical wok 02 praersf
DPhyseal relations whieh vially utect their respective growch sad
pecating practises. Inthe presen: paper acd compasion papers te
fais of is oize developement snd research work ie descr,

“Tae puezent caper, Port TH of tlm Symp, i oonncere wich
ucblests of indhetion ip eephinie renls onder normal operating
Soaditions of power systems which seule in neive, Part TTT othe
Symposium eats of induction ct tie power system fundamental
Freeney, priapally that oceussiag at the tine ef grounds, sine
drei of ther abnormal conditions of power systems, Part IV af
Ue Sypesiua teats of the physical relations and ofthe special noise.

sett ate Mats Eaton he ke New
JOINT pevetar WRN? AND Note PREQUENCY ENDUCTION 188

Frequency aul low-feequeney problems hrovght about by the
Imexiity of the svo types of sevice when ereupying the eame poles

Tre Juin! Sulcomuniceee on Development ane) Reseach bas sub-
Avil ils work among eleven project comimisrees and assigned
tach the eeutal carcying on of specie research work. Cert of the
project comuniteees are ensased on the yrublems described in this
paper while the remainder nre concerned with the development and
feeeavch problems of the companion papers, Parts TTT aad TV of the
Symposium, The names of these project committees, torecher with
f statement ot the phaee of the problem ennsidered By eae, ix gen
Volume I ot “Engineeing Kepocts of the Joint Subeommiteee on
Develepinent ene Research." *

Naturally te het sep taken by the Joine Snsconumittee wore the
review and apprasa!ofexetng information a che exchange ot data
hetween the ewe inceress represented. ‘This paper includes a state
rent of the problem, with some rien of the factor involved, te
results accomplished by che subcommittee and the work projected in
‘connection with each fector

Cuassuncattos: oF Factoas Cosmunurase 19 Isotrtos

There ate certain characteristics of a power iret wit its seociated
appacatss shat deeermive the exarecer and intensity of che electric of
Imaguede fed which is se: up in the surourdizg medium. These
Charaerereics are fesaed Tenens Faetare!

Tikes, there ane certain chiririeatice ef 9 eammmaieation ire
it with ih smeciated appesion which deermive le respon sivenene
to external electric or magnetic feds, Theee characteristics ae
teem iis Sunceptiveness Factvs."*

“There in Hin! group af Tastose which rele to che iatereation of
atighboring power and communication lines by electric or anagnecie
induction o¢ bot. These exe trmed “Coupling Factors."#

Inductive inteierence ie thus the manifestation in the telephone
"sre os combination of ieiuenen seanptivenes ed oping

indus eaortna on tons he crtod wf cars ll heer

these cles to the degree requied for satisfactory operation of bach
Marnoos oP Coxrnon,

“Pyrizat Seporovion—The ose method whieh comes ca mind for the

control cf inductive efets is that af physical separation ebteined by

placing the power and telephone ines om separate routes, A sepaction
eewaun lings of few handel fer practically linia che nose
frequency problem wheres the er regency problem may exist with
tnwel greate> separations. Since the same customers desi both
fommanation ad ower sre le two kis of tition Bs
fre nec often lesial neraie seeeivandhighovase. Power
‘tasamission ine ad toll tlepha lines do ne, in general, have ta be
placa particular routes and, thevefone, separation ea often be
Employed where sac lines re involve. Cooperative ava pla
ring on the part of the utilities in laying out their plants makes it
posse to employ separation whe it realy eased anon
el

Iremwncy Sepasasion —ssother methad of fundamental impor
towne ete use of Fequeney sepasation. By this method, cicuits to
Tre ordain! are ereanged so as ta be veeponsive to decent he-
quencies or Bane of Iroqensaes an romani: rsp
the frequency or bar of Ireauencies erage for the othe certs
Ite thus posible to male macy iflereat uses uf electricity volving
trams in the sae svete. This solution i aiiar tn in
the cuorination of rao serves

Tle, {shows diagram of Uhevarkoes uses ofthe frequency specteum
for secre transtsison aad Ue manner in whieh power cad enn
monies series axe eooudiaated hy means of feequeney sceetiviy

“The fint commercial eleeriral energy available was inthe form ot
iver current, ‘Shorty thenester,sltemating current wae weed for
the teanemnission of power. The nominal frequencies of the current

oc this servi in the ester days range from 1634 eyes #186
yet In American practi te fresno ued for june pret
fave practically seta] cown (a wider 25 gr icy. There one
tenth Sikeyele system and Tew old frequency systems, These

of M5, sl 40 eye, ad pera others, are eng rapidly
tliminaet, loe othe importance of interconnecting them with lle
fyele systema. At the present tm here's rome zendeney for ae use
DP higher Fequeccies in specie! maine &iop applicators. ‘This us,
ft present is pzcilly at 180 cycles and need moe concern us here a
ice extent i ueally confined within aetary ling.

In message telephone srancmiaion, the prime consideration is the
luanesisson of intlliible speech, While the range of response of
‘he fuman ear is fom alum Té tyres to 18.000 eyeles per seeoad,
‘human speech occupite a mirromer range snd stil narrower band it
adequate for ineligibility. The prevent voice frequency telenhone
rein eqeilly the longer ones, operace within a frequency ha
(steal 250 Io 275M eyales por eecond, The broqueney ately a

435 to BODO eyeles per second, thus oveHlappng the fundamestal fre
‘quences used for power tansnission.

(Control of Power Letle-—Cooninaton by frequency. separation
Decomes inadequate when the power levels of the warns clases
services differ geatly as with power and telephone services.” Ths,
fliiough incidental jowers ah nanan une power circuit funda
yextelfrequoney are aepligble in comparison to the pemwer at the
fandansencal frequency, they a lange tomparel othe power em
played inthe saphoue coe sue al dvertly witht she frequency
range othe :elephone crete,

While the posters invalved in (ephone cansaision ane sea a
compared to thse power Ses, Hey are iw tae Tonge ae compaced
tothe acousticsl power received {coat the talier or delivecel tthe
Vstenee.. The ordinary tlaphoae Lansanittr isan amlifer, delivering
to the line several huméed times the voice pow whit acluate the
Gaphram. On the other have the reariver requires an elveries]
wer channel or more tees hat whieh fe delivers sound 20 ee
Hateners eae

Tis nbn that che relative levels of hiemoniefrequensy power
in the per circus and voice ‘requeney power in the zelepeae c=
cuits are of maior impersance an induetive coordination, These co
Sider ens: hae il Lage il nthe oer eld inthe comer
ff wire ef cots rene aed eransformers, and fe the
telephone Sed in Sixing italien such factors ae wive sees, spac
ings of repeater anc instrument eens,

Balaree. Amwig. the sel implant methods of oodiasting
ower and comnminicstion eieuits isthe control of their respective
balances to around asd co each ether. A power ciccuit with aberlutely
balanced voltages and cuvreniaimpiesel and with the various can
ductors area in such 2 way that they would not eetablish external
lectrie or magnetic els, would not have any effect on ary type of

eighboring communication Ene
Tikewis teleshone sien whieh there were no urbane ml

Bu which che conductore were arrarged in such away chat fe pres
lensrof st eeciie ue magnet el they would not have any yay

induce hewn hem wma wae nay Ir ey iho

fawn rein, Sich an teal state fable, Dt ah es ee
seciralished by cae i che design of the fines al equipement ad by
the Iesasgnstions of the eulctos

‘Skiing 11 yi ts eatery eect ler els hy inter-
posing Uetwewe disturbing and vlisarted conduetore grounded coe
‘Buotor surfaces koma ae sels, “Magotie fields can Hawise be
choca iy nterpsing conducting othe which circulate correns
vec wacounter magnet felis Titeower aa tleptone cables in use
tev baby he simplest examples of hieking. A cable sheath is
Sion 100 percent eective ax 9 shill for electri induction, citer on
“hyamercalleor naa telephone cable. These les eflecive ss
thie far aznetie toeuction, because of is fnite vmuctivity. He
doce not stem Tessible at this tine to obtain anywhere near perfect
get sbieling.

FFacrons Coxnamutise sa NoteR FRRQUENeY Inpucriox
Senos Pacers

“Prewwave twa choractecstcs of a power system which are of primary
isoetance ia decermining its iva ive fnuence upon neigh>oring
lepine systeis, fe. its wavenkaye wal ils balance. The wave
sles + determines by charicteriee of apparatus associated with,
the system, The bale i determined by the degree of symmetry
‘tahe suppl voltages ld imece, and ofthe series impedances
tnd shunt edmittances of che Haga, While it i not prariealie to
design rotating, machinery ov other apparates weg magic eres
ttrely freer harnics, 9: eee ie eal Balanced hehe
fete itis practicable ty corte! bath these fetare within Brite

‘which in wonjunction with sar dpe of emer the ein,
fnd fx the siseeptiveress «te comuricarion eirsits, ert
fatislactors opecetion ol Leth eeisirse withow™ sale buslering

The work on infu fortune whit: has been conducted Sy the
Joint Subrommiteron Developers ara Resa has hereore, he

ieected for the nna! pare onal the sry of the wve-shape care

tesistics of power nyseims atl apparatus and methods for their i
piovement an the investgstion rf fnons fet the balance ofthe
ner spain ai sethod for their conte

TViase Shape initiating its wor on iduence factor, the Joine
Suhonmiiztee found litte ivonetion avaiable ac to. wave-shape
Iwi sarghe be expected om apr ing power syeteme equipped wil
Viious ospes co apperetie, In ender to ebtein a bral pier of

seuveeaqa excitons as they exist the field, che Sulionanitive

rye shane coon er opera

ccorueted sn estensve suesey ot

ingrowersystemsin she easter al af ibeenwatey. The pwogyant Was
‘range t oan indceration a the average ad range 6° gh
fuses Tornwnies sewent kn ware ese of tramision ana ist

bution systems under normal operating eoditions, co obkerve the
elati besween the wave shape af generating machinesy under open
ecuit conditioner aml a, to sty the ees of various teens
nemee connections on wave shape, and te observe the elects on wave
shape of various ¢ypes ane magnitudes of load

“The messuremonts mide included gnalyses of the phase-ro-neuteal
‘and phse-tophase voltages ard phase currents on a large number of
feclatowe, tarsmission ince and distibution feeders. Whetever
Dracdesble, data were obtinnd eta the babivee of the erpnstng rps
ems by measorements of reidval vole ve residual vite
‘Meseuremente wore sls rade of tho Telephone lmerfereace Fests
et te wuragie ard rarren'e Whine ie egone sri exponir le
fable Zor test purpesesev'ted, ruse measurements were made on the
commun:cation lines to aid in deermining the relation between puwoe
poten wave-enape and lance and telephone cievait nose. The
tual measurements were for the most pare conducted by the operat
ing companies with the cooperation, during the Bret part of the teeting
rogram of representative of the Joine Sulomaitee

Mie nase of data aecumblatel during this survey is being summa:

laod in several cechnieal reports which itis anticipated wil yield muuch
Yalusble infomation pertaining to the wavesttaoe problem. An
innpovtant practical appliceton of thse ete wll be in conzection with
the prediction of waneshape conditions on new Knes whicr art
Invalved in esposures wth communication spsteme orsl om which
cieeetinates are derive

I general, che survey ata ndicase tht the maga of te
Tharmemnios present in vleage and eerene die ih incr,
Frequency, with the exception thal x poneuced dip cooues ix the ze
fon from SU Lo 1800 eyes. This fm Coubt, afoul ef the eres
It The marke designers uy eewelywmtecl the harmonies in this i
fertinl region. Frequcucies aluve, 2000 cycles beeoine ealieaicly
inal ecept where thee nay be intoduci on the power circuits by
supespaed cariercoasnnunicadon or sigualing serves. general
Ue Crequenciey used Tos sul wervicew Lave Lee In the sange fm 80
16-200 ke. hich i above she vange entpleyed fo: cever communica
oa on telephore lines

Ta the gencce sree af xeve-ahape, no efor ere made tn ace
fetdere "20 ve in hes of eluctie ferferesce. aide oom Lhe

survey wore, however, mete ltver of he Submit: hast p=
FErinctor in b number of Savestigations of auch eats ia which power
syatert wavestape wes a inarcant Gee Much valuable data as

to waveshape conditions ander which coordination dlietioe see
tepevieneed have been abtained from these ste, wile ia obtaining
heee dats the Subcommittee eprementtives have hoes of service
‘he Tol companies in the slat of the prlielar probiene
parquascy 1spU

Avital ameun! of hectetical werk hee been carried on aig 1
Gorwih ihe efits of lout en the asmorice observe in the oa
Sltcuie voltage of cotsting machines, "Thos work whic wat based
lends ie as ion theory ae supplemented by lahrateny” ts
fon several small mavhines. It was found that the reactions wich
Tae place wath the rotating machines, particularly when (oor mre
wre eherating in parallel ev sn vonplvated ae to practically precade
route eompucatons of the wes. However, the dats obeained
Som this investigation ave been valuable im conncedion wth iter
stati

“Balance. A bolonend power circuit is ore in which the vokaes
‘ewwsen the various pase concustrs gral grou re malin rag
inde and sump ves tory 20 abs0 and in which tbe phase eurenta sr
tho cqul a meri and sus ap veccoilly to geo, Tra care
se nyatsan where the currents or voltages ure wt exalt los
tn tao che currents or vellages aa be Zeolved into two balanced
Unvesine yatem, one of yo plaaeFequetce and one of negetive
itn sje La cases where the currents or voltages do not sum
bin tn mera hey’ contain w single phase component which is usually
evo residual of rer phase seuence component. Any three phase
syste can Be ceeolved into its Falarced andres mpenents sl
Gheh cated separately. The coupling foe the reslual example
ie anual suc larger than forthe balanced com pores ans there
fice ently of major impor-ancein cooediresionneablens. Dier
fences toe maghitedes or egustines Som phase syrome re af he
three apres phose-orventes. voltae, lose oF line unbalance,
sive ee to residual cusents or voles

“Experione husindicated that the oulading factor in the unbal
nice af ner stent isthe essence of eiplesuarmorie voleagrs and

Eunents which may ise wither In sotating machinery or i eae
Teens hich ave connected i wae with zroaded neutral. Siow che
{tile hanno volages'n the chee phase-to-restrs Teg ae in phase,
thew set in a pot const ag ef the phate csmdvcsons aml an eateral
Fett for instance, © eae neutral er grt

‘hepe meastre of oonlcul aay be rveerite on the zgntuses ot
the urpi-harvoni esl voleagee id varrents by the use of eereain
framcoemer erste a by nat operating he transformers at igh
Mux densities

he mites of tipl-kasronie residual cuscents in ground
neutral synergy be siniminea by These of staeedelte connected
Cranciormery in which case nearly all the requieed tepleshormmic
Content cireatesin he delta, ‘The opie exlzeme occurs with star
star connections ip wisi ease che (ull .ple-sacanee anagutiing
fa ient tows inthe twn eyeteme whieh the transtruie iene!
the slative magnicuéts in esch cepending on heir relative inpedances
Where star-iar bank ie consectot atone terminal ofa Tine, with a
stardeta at the ether, the neutale ab each eal being grou, prac
‘eally the entire third harmonie required by the stac-star bank may be
expected to ciculace inthe line connecting the two.

An eective method of canticl tor ets in which staratar omnes
sie ae rogue diet pas relations s the provision of tied set
ef windings ur terarim in the trissrrcers. she impedance of the

fers with respect to the cher windings being sullen lo t0
fer ada pls fr the ripen muerting everert
Aveasermace method! contre, which al neovides te phasing om the
too wiles of the bank, it the ase of riz-ze connected! eansformers

Ta fourvire emaldrgroutled wenlcal disuthudon systems, Th hab
‘hee found helpful in contolliag se ssidual tripe-haenionie curredia
fom thesnglesphace lod tranalecates to provide stay-delta cenaccced
tanks at varios points in the network with neutcalx conneesed t0 the

stem nexcral, In some sors, theae have been three-phase load
Tanke in thers special hanke insalen a a method of contr
‘The altconitee contig ils wack on wave shape an lance

AHhongdh on biluratory stay nstorr brani al Hrs
fongesiors. These test ave being wade on mall mavll transformer,
bypical of He digas whic ave won for “arge sizes on “rans,
seins. 11s pzanel to develop che sheo-y appliable to hase
Teoma trancformere on chece-phace systema from the work an these
laboratory mode's. Tt is planned ro eupplement che wrk by cet
‘om linge transormers in the manufacturer's shops a in the eld

Avinmber of severe tie situ have been creed ring Ue
teat few years when slareimneriel generator, operating wil
‘rouuuled neural *bave bach connected directly or through staratar
Uanaformer tans te tranenssins oc ditibution systens. The
incesfereace in tse nes eel Iron vigle-barmorie esl one
Donenes impression the system by the particular gnerstor operating
‘wits che goznded entre, The magn cues ofthese curren lepend
tia the teiple-harmonie components in he generator pace Uo neutral
olla so the impmtites tyra ut use stem. “The wechonds of
hndra whieh Taye leew surely apple in se eases inlusle the
Fallow:

1 Tang the generator aeutsl and supplying the system goound
‘thaough suitably designed teanstormer bank.

2. Grvsning the noutza af only Lowe genecetore devigucd to be
foe fro role bassin in thes phase o-neutal voltage
4. The ue of slertive devices sue a5 reactors or and-rewmant
ireaits commonly eaed “wave tips” ia the generator neal for
Snovesing the distcbing trile-nnie components.

Nowteiple heron eesidual voltages and eaeents may exist from
sliferencis of phase-tnvenral Ina Epedances and From difleeres
in the eapoetances to grown of he thaee phase wires

Th maltgruaided neutral fr see ystems diterencestn he singe
hin Ita ronnected between ‘he ilivual phares and the reuts
tray: be inortant sowie of resid enerent. Acsiderable measure
Uk cntnal may he eercse iy vesting the sie of single-phase areas
vl bnsaing te foad on the diferent aes

Capacitance untalance to grimal ney be due uy se phase
Irasches 1 Uecephase disrtuion systems, Usually, the mone
instant flee fe fott om the sing phase Inanel where the cela
‘altage i iasteally equal 20 the yltoe-toneutral voltage. The
abaigrsing effect on che theerphae system may he misiized by
feqalizing th lenis of the branches connerte tothe sever pases
‘The residual voltage om the single-phase branch am, where weer,
beiminate by the use of olating lanstormers nr by converting £08
hers Inna

(Capitan: uabalasce may alsa be eve to eeeynametry ia ee a
rugement uf Uhe wires of the civil reach other and’ ern
"Thee urvalances ave lowest im Insular enatiguacions of che wires

jal largess Wer all the mices ane in “Ie wom vertical ce horizontal
Plane. With avulenicene Enos, a ronwidavable measure of evitral
thay be obeained hyp suitable plata satereonsceton of the cist
‘Transpesitions are als efetive in teeing these unbalanoes

Conplins Farle. —The coupling betwen poser nat eonnuaication
eve if conse, determined by the drgtee nf their prosiity, but
ity he grvaly soit bythe sce of the two classe
oveach other and with rsp to gerund. Walle the mae diet aul
evan method for reducing siping is avoid peiminy, sear
hue availabe fer minimizing the coxpling where resmsany

The work cr romping ofthe Joint Sabrommiter ew Developnent
sid Reeserh, in the woige and exiveedrequence range, las Leon
tivectedteward two objectives: (1) devrlopment of eyruvedl methods
lor yeesievernising she coupling ca be exeted in ew eas of expo
see al (2) sevelopaent of iapvoved eerhods fr reducing cowpling
for giver degrees of provi

Severs) years un the Califor Joine Committee on Twaactive
Incentcence "complete eine s:e2 ob coaupieations an ene
cena ol iiacn whick were expressed inthe oer of rureen Zor