Palmerston North Electric Power Station Inc.
Background
to our National Gas Engines
So around 1920, the authorities still didn't know the best place to build the power station. Had it not been in this present location, possibly the likely alternative would have been in the vicinity of Rangitikei Street and the present post-1960s railway station area. It seems likely that it would not have survived to the present on that site though. The land there is now far more valuable than its present site on a hill adjoining the cemetery and alongside the problematic former gasworks site.
Of special note, as shown in the photo below, is the size of the Nationals. These towered over the British Polars (which are tall enough themselves), despite having far less generating capacity. This photo dates from around 1945.
Manawatu
Evening Standard 7 October 1921, p. 5 (col. 2)
Generating Machinery
For
the Power House
During the past few months the machinery for the municipal power house has been arriving in Palmerston North and at the present time the greater part of the plant is in store. Since the component parts of the plant are of great weight the task of transporting them from the railway to suitable cover was a big one and it was during the course of these transporting operations that the regrettable fact that a site for the power station was not available was brought home forcibly to those concerned. All of the machinery will have to be handled a second time in transporting it from the store to its final resting place at the power station site. Had this place been ready, the large and weighty pieces of the power generating plant could have been taken there directly and much useless labour and expense would have been obviated.
To conduct a power station successfully
and economically, it should be situated in close proximity to the railway, so
that coal may be transported from truck to bunker at a minimum of expense and
delay. Hence, the present position with regards to the railway deviation at
Palmerston North, where it is not known exactly where the line will run should
the proposed deviation be affected, has been responsible for the delaying of the
action in connection with selecting a suitable property on which to erect the
power house. However, just as soon as the Government’s policy in the matter of
the deviation is available the Borough Council will proceed with the work. The Standard
pursued some inquiries with regard to the establishment of the power plant and
these facts were ascertained.
Two complete engines, each of 450 h.p., have arrived, together with the gas producers and all accessories. A third engine is on the water and should arrive here shortly. The switchboards and electric generators are also expected to be landed soon. In a store in Grey street some 180 tons of the plant are in store, while over 30 tons are under cover in the railway yards.
There
has been some discussion in various quarters as to the advisability or necessity
for the establishment of a generating plant in Palmerston North in view of the
fact that the completion of the Mangahao system is but two or three years
distant. But from the experience of practical electrical engineers it has been
found that a subsidiary plant is most useful, if not indispensable, as a
stand-by. Breakdowns on long extra high tension transmission lines are not
infrequent and a stand-by plant is very helpful when the main source of current
is temporarily out of commission.
The
plant to be erected here will, in the opinion of an expert, save the Borough
Council much expense, since it will supply power to cope with excessive demands.
If the stand-by plant were not available, the Government power would have to be
drawn upon to meet the full demand and, as a consequence, the council’s bulk
supply current would be greatly increased. On account of the ‘maximum
demand’ system, which obtains in Government supply schemes, a heavy demand on
the current, even if only for a short period, causes a very great increase in
the amount which a local body is required to pay for its supply. The saving
effected by the carrying of this ‘peak load’ by a subsidiary plant would
offset very largely the initial expense of the installation. A ‘peak load,’
it may be explained, is a load bearing practically the full demand of the area
supplied. On a ‘late night,’ for instance, with picture shows, shops,
offices, street lamps, elevators and other consumers all drawing on the current,
in addition to the ordinary household consumers, the load would be termed a
‘peak load.’ All estimates had to be made on the basis of such a load.
Arrangements to commence operations, as soon as a site for the power house has been procured, have been made by the contractors, so that within a very short time after the decision of the Government with regards to the railway deviation is made known, work on the power-house will be commenced and ratepayers will also see something for their money. Also, the reticulation of the town is to be commenced shortly, tenders already having been called, and it is anticipated that the poles and wires will be erected in time to link up and switch on the current simultaneously with the completion of the work at the power-house. The reporter who gleaned this information could not obtain an estimate of the time which will elapse before the electricity is available. Labour, and the shortage of materials which prevails, would, it was stated, probably make for a delay, but everything possible would be done to expedite the work. Our informant added that Palmerston North was a town of great possibilities and, with the immeasurable benefits bestowed by chance by cheap electricity, its prosperity should advance by leaps and bounds.
Manawatu
Evening Standard 21 October 1921 p. 7 (col 4)
Electrical Supply
The
Proposed Power Station: Facts about the Installation
Some facts
concerning the plant to be installed in the power house which is to be
established in Palmerston North at an early date were ascertained this morning
by a Standard reporter.
The three engines which are to be installed have been built by the National Gas Engine Co. Ltd., one of the leading firms in Great Britain for this line of work. Each engine is capable of developing 450 brake horse-power, at 300 revolutions per minute. The engines are the three-crank six-cylinder type, the cylinders being mounted in pairs, one rod passing through the two cylinders and carrying the two pistons. Each crank receives one impulse per revolution and as the three cranks are set at 120 degrees apart, the crankshaft receives three impulses per revolution. This gives the same steadiness of speed as a six-cylinder engine, such as is used on the majority of high-grade automobile engines, and is as nearly ideal as can be desired. The engines will be coupled direct to three Metropolitan Vickers three phase electric generators. They are each rated at 340 kilo volt ampers and generate at 3,000 volts.
Of the most up-to-date design they are faithfully built with that thoroughness of construction that distinguishes British machinery. The electric energy generated by these will be conducted by suitable means to the switchboard where, by means of the most modern equipment, the generators may be connected to the cables leading to the street mains. Each machine will be protected by an automatic device, which interrupts the circuit in the event of any serious trouble developing in the electrical part of the plant. Each section of the town may be supplied by its own set of mains, which will be fitted with automatic switches, similar to those which protect the generators. These will operate in the event of a heavy overload or a ‘short circuit’ on any part of the wiring to which it is connected, thus protecting the generators. Normally these will operate only in the event of a broken main on the poles, as the fuses and circuit breakers installed by the users of the current protect the mains against any trouble on the consumer’s premises.
The engines will be supplied with gas by two coal burning producers, each capable of supplying gas for 700 horsepower. One producer will therefore be able to supply two engines in ordinary circumstances. It will thus be able to maintain one engine and producer as a stand-by plant. Should the load threaten to become so great as to exceed the power of one producer the other producer may be prepared to operate in conjunction.
In practice, it may be stated, the average ‘load’ in any town is not difficult to deal with. The closing hours of workshops and factories and retail shops, the opening and closing hours of theatres and picture houses, private residence lighting and street lighting hours, as a general rule, follow the same course from day to day. This fact enables the superintendent of a power station to compile a ‘load curve,’ showing the average load for every minute each day. Once this has been done the station staff understands exactly what is required of the power and the engines are operated accordingly. At the same time, the average demand must never be looked upon as the only possible demand for any particular period, and a greatly increased load must always be anticipated.
A 35 horse power steam engine and boiler will also be installed. This will be nothing more than an auxiliary and will operate blowing machinery for starting the producers. It will also supply the power for a compression device to furnish compressed air for starting the main engines.
As has been previously stated in these columns the power station to be established here will eventually be linked up with Mangahao supply. The borough may then be supplied from either source, or the two in conjunction. The hydro-generated power from Mangahao will be transmitted from overhead wires supported by massive insulators on lofty poles. An exceptionally high voltage will obtain – 110,000 volts. Such has many advantages, chief of which are small transmission losses and a light weight cable. These mains are known as ‘extra high tension’ and will supply the ‘E.T.H.’ sub-stations situated in various parts of the country.
The sub-station which will supply the power to the local Power Board, it is expected, will be situated at Bunnythorpe. At these sub-stations the electricity is utilised to operate transformers, which are energised by the ‘E.H.T.’ current, and generate a current of much lower voltage. In the case of Mangahao power the ‘E.H.T.’ current of 100,000 volts will be generated by the transformers at 11,000 volts pressure. The high tension supply thus obtained will be distributed throughout the area which the local Power Board will supply.
Each separate district in this area will be equipped with transforming sub-stations similar to the ‘E.H.T.’ stations, with the difference that they will be specially designed to operate on the lower voltage pressure of the high tension current. They will generate current at 3000 volts, at which pressure the current will be delivered through each district, along the principal roads and thoroughfares. Transformers will be fixed to the poles in various centres of distribution, which will take the 3000 volt supply and generate at 400 volts and 230 volts respectively. At this pressure the individual consumer will receive his supply. Motors will be supplied at ‘400 volt three phase,’ whilst for lighting and heating purposes the supply will be at ‘230 volts single phase.’
The power house which is to be established will generate its own power by means of gas engines and generators at 3000 volts and the 11,000 volts supply will be brought to a sub-station located in the building so that the 3000 volt supply from this source, and the 3000 volt supply from the Palmerston North plant will be fed to the street mains through this switchboard. The whole of the power consumed by the borough will be controlled from the latter. It will be possible to divide the load between the two sources of supply or carry it solely by either, according to the conditions which may prevail.
The whole of the scheme, as regards the power house and the method of distribution, will be thoroughly up-to-date, and there is little doubt that the residents of Palmerston North will, when completed, view the installation with pride as one of the best in the Dominion.
Last Updated: 30/6/2001
