Home The Projects HelioTram - Introduction
HelioTram - Introduction Print E-mail
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Wednesday, 24 February 2010 18:47
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1. Introduction

Public transportation low voltage D.C. networks are particularly well suited for direct connection of PV systems because of their electrical characteristics, since the load of the network coincides with the PV production. Very simple and therefore reliable PV power stations can be built to inject the solar production into such networks, without power conditioning.

In the framework of the Thermie 96 programme, Sunwatt presented and developed the project called Heliotram, which is aimed to the connected PV large Plants for injection in light train low voltage D.C. networks. Since 1992 a small plant of 2kwp are connected to theD.C. networks of the railway and give us some data and experience to have a high system fiability.

The purpose of this project is to manufacture and install such PV power plants in Germany (250 kWp at Hannover) and in Switzerland (154 kWp at Geneva and about 100 kWp at Lausanne). This implies:

  • Direct connection of series of PV modules to 600-750V DC grid, i.e. peak voltages up to 1'000V at open circuit by cold weather.
  • Incite the manufacturers to certify their PV modules for a high voltage usage. The PV modules in use will be continuously exposed to high voltages and thus require a good insulation between frame and cells.
  • Testing high speed circuit breakers and power contactors, for DC high voltages and a large intensity scale (0.5A to 250 A bidirectional, under 1'500V).

Swiss industry is in a pole position in this area. For the PV modules we incite several manufacturer to certify their modules for a high voltage usage, solarmodule class II. The same high voltage certification holds also for the quick connections and other materials.

The system of TPG of 154 kWp, at Geneva, has started operating in July 1999. First results on the system behaviour and performances are presented.

Last Updated on Thursday, 25 February 2010 13:25