Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.mrao.cam.ac.uk/projects/aavp/posters/Montebugnoli_Notes_on_local_generation_of_energy_for_large_array_operation.pdf Дата изменения: Tue Dec 7 02:42:54 2010 Дата индексирования: Tue Oct 2 17:51:40 2012 Кодировка: Поисковые слова: воздушные массы

Notes on local generation of energy for large array operation
S. Montebugnoli1, G. Bianchi
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INAF-IRA (I)

The Square Kilometre Array is planned to be installed in a radio quite zone located in a remote area of the southern hemisphere. The power supply needed to allow the normal operations, is thought to be higher than 80 MW. At least 60% of the total energy might be requested by the central core digital processing. Due to environmental, ethic, costs and technical reasons such an energy is planned to be locally generated from renewable sources or other. The more suitable seems to be both photovoltaic and thermic solar panels. It needs to be defined how far away from the core the power plant has to be placed. If it is too close, possible RFI from the power switches could interfere with electronics. If the power plant is far away from the core, the transmission wire losses can become a problem of costs and the same line acts as an antenna that irradiates RFI deriving from the power inverters. Possible extracurrent spikes, collected by long power transmission lines, have to be suppressed before they enter into the core electronic. Spikes cause the premature aging of the devices with a consequent decrease of the MTBF. Care has to be taken to clip out all the spikes that exceeds 500-600 V.

General overview of energy generation Possible scenario

The molten salt is a mixture of 60 percent sodium nitrate and 40 percent potassiumnitrate, commonly called saltpeter.

Possible solution for DC power storage. The Vanadium Flow Cell Energy Storage approach from Prudent Technology (USA, Canada, Denmark, China, Kenya) seems to be promising, anyway further investigations on this approach are requested.

Molten salt is fruitfully used in pressure, it provides an efficient, its operating temperatures are temperature steam turbines and,

solar power systems. It is liquid at atmosphere low-cost medium in which to store thermal energy, compatible with todays high-pressure and highin addition, it is non-flammable and non toxic.

Premature aging of the devices, due to spikes collected by the power transmission lines, strongly decrease the MTBF of the devices. Present technology allows to use clipping devices as Spark Gaps, GTD, MOV (not precise & high energy) or Zener, Transil, Trisil, SCR (precise & low energy). A new powerful clipping system (Italian patent), with aging control and able to manage very high energy, is available from the Torresan Company. It is able to directly handle up to 6.5 KA (8-20 uS). A vacuum discharging tube takes part of a resonant storage system that gives back to the power distribution line the spike energy.

4000 V

Standard devices

Stray

Italy

Alarm Aging Monitoring

SDS-IND-DIN-M230VAC

1000 V

Vin=230 V

1000 V 540 V
V tresh. C stray

LOAD

- 540 V -1000 V
Protection Circuit