WATER POWER

Evening Post, Volume CVII, Issue 56, 9 March 1929, Page 17

WATER POWER

PLANT AT WAIKARE

FnTIIE DMYELOJ'MJOT

TRIPLE-STATION SCHEME

,(:By Our: Special Keportcr.)

In the last article upon the "Wai-k:a-(sui6an:i;liy"(lro-electric scheme an idoUXHs:given b£ what is still bu■yo.re'th'e civil eiigiliCLU's' in tho slor■iiig'lip"- of • ilb'oil waters ■ in Lake ■AVaik'aremoaiia to meet smuincr to-

:^.quii'pment.s • of the;-.turbines _ in. tliu powerhouse. In.-this-article an given of tho present do■,'iveio.^nie,ii,t «nd .of proposals for the -'fntlirei tlie expansion of the. scheme

into .a- triple-station development

."'',;Bqfpr.c "going oil to the. system as it ..is'.-t6-jay "it:-.wili. be well to give an ildpaspf the! country befbro. tho work iwas: star'tcd." From the rock jumble . f tlie face'from, which the overflow from •|£e Make .-escapes 1, either- over the nar!row surface outlet or through the many ■un.d.eJgii&uM' leakages,' tho..Y.aiiey. of the ••Waikaretaheke .stream falls very steep■ly: for .435 ,f ceti..;.Herc there is' a -flat of perhaps a' hundr.ed:.a;erc3, jii which is a small. lak^'Kaitiiwa; /'Over the low BdgeHvhiclubas'dammed back the water itir'.foriiirtHis 1 Maktf is ~anothor equally gtcep-'liilfei.aee -/to a much flat, Whakamariiib;r.6Bo:feet,'lower in level. Erqmf-this-second level-area the valley ;cpntinues- to'fall,.gradually at first, then 'again-almost to a third flat, SSO ,'feet belaw \Vhakamarino. In three !^nd;/avhalf/imiles .tho. river falls 1-150 'ife^'i^ '■ three;AvaiS: steep declines., '■•'tfThe Vpower-hbuso.-jus't;.. .brought into «t)iiniissi6n.i^.built on the middlo.Hat, On "the" first level, Kaitawa, .the sfnalll riaturaUakchas been Mprovcd- by an earth dam and con-crete,-vWprk. and. enlarged iv area to 'about;,fifteen.-acres. ■,Through the. ridge ■^iic^TJioidsiit ."back from.the next deifJeit ■» -iftV^lKe-foot.-,tunnel,; 67Q.fi; long, ia's been .pierced, and through it the Water as.'lecUto,ai circular concretei surge *fianib*r/3|0 "it eefc..deep;' and 100 feet in ■■aiaiiijstfer, the ;excess; ' river flow running *vsr^;-"i^eir;Tiear: the small-lake, head, 'a wild, '^o^ing'current..V^T/.,'■ '.;.-.:■ :. ...;.;■'.' seventeen: hundred tons in ':;,.£ wwes.:- ; ::.-.., _ .v.:jProth^ .the* 1 surge;, 'chamber the steel •pipe v]iH'esJ v'6ft >6in- in : dianieter at the •tqp.an'd reducing to oft I3in at the bot.'toin,\>tallt steeply;: down ...tlie hillside .to th'V.ptfwejapuse.: on .Wliakaniarino- Fiai, '• -There, are two of "these ■great/jiipp; lines in - place, . squatting heavily vWupbn concrete -cradles and held ■fop and. bottom and'at the middle downbe'ttd;:By .anchor . blocks of concrete weighing hundreds' of tons—at JNfaikaremqana ey.erj:thing • is, iv hun-_ dreds, Tvlxoreat'i-yiiot. in thousands and hundreds^ of thousands. ; -The ■ wide trenching .down : the :;hil)side, tho surge chamber,; and the anchor blocks ■. have been'designed to take a' third pipe' line when:'the time comes 'for. the'installa-tibtf-o^ the. third turbine- and generator. At" present,, with one generating unit installed, ..only one pipe line carries water;;•:• 'At^tlwhead of the pipe line the pressure/is comparatively light, so that the. steel;used.is: 3-8 inch thick, but,at I;hp .footf'.wherethe pressure is 2801b.t0 the^square inch the.plates are-15-16 inch. Seventeen':.hundred, and fifty tons of . steel plates went to the making of these •two- pipe, lines,- and hundreds of thousands of rivets. Each line is about four-fifths-of'a mile long.- .. • "The- power-house is, built for work, not -for lopks ? 7»an'd ris a '-reinforced;: con- - crete .structure squarely built. In it are\hcrased the. generating plant and thefuU'.cP'ntrdl -system. The "outdoor station)", including tho great transformers,, switches,' and so on, is .well, removed; AtManga'.ha'Q..the generators, arje'. driVen by. .Peltou- wheel turbines, but- at.'Waikaremoana the Armstrong, "Whitw'pr.th^JJtiEineisl'.reaction type, tuv-; bin-e is instilled. ■ 'The difference is that theiPeltbn! wheelis in the nature of a specialised; 1 water wheel, many jets of water: : .;Un.der;high.'pressure I playing o,i. the! cups bf the whirling water wheel. The'reactipn type turbine is more after •the ■'style; of-a«steam. turbine,' in which the. .wa,ter>iis' >:'directed:,by- one set of' sljtipnafyvvjiftesr.upon vanes on the yhifjjng-ifplprj-'an.d jjemairis under ■full. pressiiro-,tin:fcilH.t\pdurs -from the turbine, casing." .:. The "Pelton wheel is spun^ thpugh sgiinisa hopelessly, inadequate . word,f or, -g^eat machines such, as these -~by.'_, the impa.c t of the-high-velocity jctsfi the "turbine proper is s.piiiv by-the. continued'"pre&sure of tho.'water.-Local conditions," such as available head,' do-V terming' Which, type; shall be employed, lnilcac'n.:':case; .the .generator is coupled, direct, to the turbine. , , ; ; V.- A. MARVEL OF CONTROL. :'.A-very wonderful feature, to-: -the' Ippker-on, is'the manner in which this .luigej. combined, machine, tho funuiiig part of which weighs, 65 tons, is autpr «atically .governed to-.deal' with the <T.ieryry-a.ryiug>electrical,-load.-. It-is-a, %istaKe to think that because thegen-' eratpr -revolyes,always at tho same speed' (428 revolutions per: ininuto at ■Vyaikare)'it:is"cbhßtantly generating its' full, power, i. ■ There is a general idea that :duririg th.e-night hours, when few electrfcally\(lriven machines'are operating and household demands are: over, "ppjver is 'runjiing to Waste:" Notli-: •ing;'pf-;the...sbrt:-,pqwe.r.is generated bythese '"great - machines 'paly, and : their immediately," when it is, required, notwithstanding- that.-the generator -specd 1, is;constant through; the twenty-four hours ,'of 'the. day. ;; - 'if „one: pushes a bicycle along a level road' at ten miles an hour a certain amount of pedal pushing-must be done; If-one rides a bicycle at ten'miles per hour uphill tho pedallmg' is' stiffer/- The demand for power, to light; a lamp in Napier, to drive'-a fram in 'Wellington,' to boil an electric,kettle in an up-country farm■.touse,::provides ;the:.uphill going for tho 'generator. To., caruy tha ■ illustratiou'. to an extreme: if there wasi no demand whatever upon the station, the station, though still running at its constant rate, , would: actually generate no power at all./ .'.-.; '.. ■; . ; " ■' -.. -. i ,' In -a hydro-oleetric scheme water power and electric power are, so to speak, one and the same. The power of the water as given by high pressure is merely transformed by the revolafions ,'of the turbines and generator and the/play of magnetic forces into electric power,-and were it not for the machinery, and friction losses the rela.tiq'ri between water consumed through tho driving turbines and power producc'l by the/generator would bo in strict proportion, i.e., 1000 kilowatts, so mtich water; 10,000 kilowatts, ten times as much; and actually there is a quite dVflnite relatiou. When tho demand for; power is light, little water passes through the turbine. When the demand climbs .high the water roars through in.'a flood, and it is through the , marvellously accurate automatic control of water flow that,generator output is adjusted- to the demands of tho monien.t. ■.;■'..:

. At Vr'oikaremoana thero are several systems of control of water /low. There ■i$ .oiio' at iW.topiend of the-pipe-line, ■«• system, of gates, .which may be operated by. 'electric' motor or by hand, to shut djff; or ,open the-'flow to; the pipe linen. At'.tlle f9'6(;;:.oi J each pipe line; the.ro is a.;:needle.. valve (a, carburettor needle valye^on. a'giant-scale), and rouridthe iilsiiJe L of'the twrßine casing is a series of,; mojea'Ble ,c.urv.e,d<varies (technically kiioiro. as"gates") connected to a moving'ring,:which in turn is connected

to the governing apparatus by \\ Ji.cs.ivy, steel arm. As the demand for power falls the generator tends to spceil up, the governor moves tho steel iirm a trifle, closing'lliq va.nces and redui'iug the volume of water to the .spinning turbine rotor.i. As the load comes on tin; vanes'are "lubveiJ, back- and Iho How of Vv.'ifer'iiutomi.iticnl.ly adjusts itself to the: demand. this ponderous adjustment .continues,; second by second, hundliug a river, oi'-water at high pressure, timing tlib revolutions of ■ 65 tons of steel and of coper windings wil.li a precision -that-is. almost übsolulc.