NEW PLYMOUTH'S ELECTRICAL DEPARTMENT.

Taranaki Daily News, 8 May 1916, Page 6

NEW PLYMOUTH'S ELECTRICAL DEPARTMENT.

IWliOUtifl ENCfiNiiiiK'S liJil'OHT. Mr. H. Black, electrical engineer, lias submitted the following report to the council on tin} operations of the year cndciil March 31, l!)l(i: The chief works carried out were the new transmission line via Mangorei Road, reconstruction of the original Avenue Road, extensive alterations to overhead lines along the tramway route, erection of new switchboards in the new sub-station, and removal of existing switchboards from the old sub-station to the new, all the above, work being carried out by our own staff. The new intake was put into regular service on January 10, Ifllfi, and lias greatly improved the supply and provided ample water for present requirements, with a fair lhargin for future growth, even when the river is at its lowest level. The conditions of operating in connection with the new- intake are not exactly ideal, as at present it is neeesary to carefully watcll the rise and fall of the water and regulate the gate opening to suit this and the varying demands of the lighting and tramway supply. The automatic gate gear, as fitted, was not suitable for the- work and had to be put out of action, but it is hoped that the proposed spillway will be of sufficient capacity to deal with any flood water and thus reduce attendance to a minimum. At the present time it is neeesary to have a man in attendance at the intake every Saturday evening from 0 p.m. to 10 p.m. The new transmission line was put into service on December 12, 1915. It was forunate that this line was available when the temporary tramway service was started without the battery,

as it would have been impossible to maintain a steady lighting supply over lines also carrying such a varying load as the tramways have given. 'With the new line in commission we have been able to run a separate generator and give a distinct and separate supply for the tramways without in any way inter- ■ fering with the lighting. At the present time ,t is necessary to devote a 250 k.v.a. generating «e't to tramway work, with a load varying from about •20 to 250 kilowatts, lnit when the battery is connected it is expected that the load will bo kept to about 100 kilowatts, except during rush hours, when it may' be necessary to run both motor generator sets. The reconstruction of the original transmission line was completed in ""February last, but the line voltage lias not yet been raised owing to some of the protective devices required by the Public Works Department, for protection of low pressure lines not having been com-, pleted. This work Ims just been finished and we expect to be ready to

raise the voltage in a few days. 'This should very materially reduce the loss in transmission, and will be a great help to us during the coming winter. The new sub-station, started in February, 1015, was completed, as far as the builders were concerned, in February, 1010, but before that time the new switchboards were in position and ■the tramway motor generators put ! down. The main (iGOO volt sv.'itch- [ boards of sheet steel, cubicle type, consists oi eight panels, one instrument, ■ three transformer* and one tramway panel, and is fixed in the wall between .the transformer room and machine room. | ' The transformer room is divided into three bays, in the first of which a 350 'k.v.a. GGOO-2000 transformer has been placed. A second similar transformer, at present in use at the power-house, will be placed in the second bay, leaving the third as a space for future development. The 2000 volt switchboard contains 0 panels transferred from the old substation, as follows:—Three transformer panels, one instrument and coupling panel, and twelve feeder panels. The new portion of this switchboard was erected and the lines transferred from the old sub-station, after which ilie original switchboard was dismantled and re-erected in the station, nnd on April 20 was connected to the supply, the GOOO and 2000 volt switchboards, with the above transformers, give a very complete equipment, and should meet all requirements for some years to come.

I Besides tlio above there ia also a street liflitin" switchboard, three-wire *l4O-220 ; volts, comprising six feeder-panels and la two-panel series lighting board. | The tramway generating plant eon- ; direct coupled to ,00 kilowatt iinn volt sists of two 135 h.p. fiOOO volt motors, DC. tramway generators. Battery with reversible booster, negative booster. and D.C. switchboard, comprising two machine panels, one instrument panel on reversible booster, one negative booster, and two feeder panels. The alterations to overhead lines has entailed a lot of work by the. Electric Light Department. By agreement with the telegraph engineer it was arranged over most of the tramway route, to avoid carrying service leads over the trolly wires, telephone service leads and electric lighting feeders should be run on both sides of the street, the tramway polos being of sufi'iccnt height to allow the telephone lines to occupy the tpp, with electric light and tramway feeders below. As the tramway poles were erected the lines were transferred and the original poles removed. To carry out this plan it was necessary to re-arrange the circuits, not only along the actual tramway route, but also in a number of adjacent streets, and this, with the transmission line erection and alterations, kept our outside staff very fully occupied during the whole of the vear. It will be a month or two yet before all this work can be completed, after which there is some street lighting to do along the tramway route, and several works authorised by the council, to complete as early as possible. It will be necesary to put in a new generator at the power-house very shortly, and this will entail some alterations to the building and to pipe lines. T propose reporting on this more fully as soon as the line voltage is raised and the tramway battery in service, as we will then be in a better position to jud°;e just what our working conditions will be.

During the year there have been several changes in our staff; Mi. Randilanrls, who lias been engineer at the power-house for over ten veara, left to take up another position, Mr. Malt, first assistant, being placed 111 charge. The starting of the tramways has necessitated the employment of'attendants in the sub-station, members of our own staff being employed for this work, leaving us short-handed for tlie ordinary electrical work. We have also recently lost two of our o/i'iee stall', which, happening just as we moved into the new offices, bus somewhat disorganised things, and some animal returns are not yet available, and cannot be included in this report. We hope to have these ready shortly, when I propose to submit a supplementary report oh the figures for the year. X would like to take this opportunity w QXgmi *»prwlAtl«Q Of the work of

the several members nf the staff. When required, extra service lias beep given willingly and the work carried out with )t minimum of inconvenience to consumers and without any accident or mishap of any land.

MONTHLY RUI'UUT. Mr. Black, in his report for the past month, states: Puucr-liouKc.—For tramway supply we arc running one of the 2jo K.V.A. sets and using the now transmission line, thus keeping this service entirely separate from our ordinary lighting and power supply. During the day-time the other 2;>o and AO K.W. sets are generally suffieent, but now that the nights are getting longer and the load greater we have to run one 45 as well, and on Saturday evenings have had every machine running. The raising of the transmission voltage, which we expect to arrange during the next week, will reduce the line loss very materially and thus leave us a, better margin, while the battery should also assist, as it will reduce the fluctuations of the tramway load. On April 10 the plant was shut down to allow an inspection of the tunnel to be made. The result was thoroughly satisfactory, all the unlined portions appear as good as when the tunnel was completed, while the invert wis cleaner than on any previous inspection, due perhaps to increased velocity of the water with growing demand, and partly also to the dam at Mangamahoe acting as a settling chamber. A quantity of silt, sticks and other debris had to be cleaned out of the forebay, but not more than on former occasions. Work on the 2000 volt switchboard, which was moved from the old substation, was put into service on Saturday last, April 29. The protective devices' required on low tension lines wlicVe run on the same poles as the transmission lines have nearly all been fixed, and we will be ready to raise the voltage in a few days.

During the past month some further 'alterations to private and street lighting lines have been made, mainly where they are run below transmission lines, bare wires being deplaced by insulated cables as required by the Public Works Department.