knjiga solarna energija dobra

PV POWER SYSTEM CONFIGURATION AND APPLICATION 761
17.2.2 Photovoltaic Systems for Remote Consumers of Medium
and Large Size
Electricity also solves other supply problems. Workshops, food storage and processing,
telecommunication, health services and tourism normally demand higher daily amounts of
energy and power than can be supplied by a Solar Home System. The usual supply levels,
classified according to small and medium loads, and local, regional and national supply
with the corresponding voltage levels and power ranges, are illustrated in Figure 17.8. For
very low power requirements, pure photovoltaic systems with an appropriate energy storage
unit are the best option. With increasing power demands, other electricity generators,
like wind turbines and solar thermal generators, become technically and economically
attractive. Small stand-alone grids that are supplied by various electricity generators are
the next step in remote area power supply. With increasing demands, the connection to the
public electricity grids makes good sense. Here, of course, all renewable energy technologies
can play a role; the decision on their application, however, has to compete with the
energy prices of conventional power stations driven by fossil or nuclear fuels. Because
of the price reductions in the last years, photovoltaic power technology is cautiously
expanding into the range “supply of small and medium loads” at present.
17.2.2.1 Photovoltaically powered telecommunication system
Owing to their high reliability and low maintenance, photovoltaics are already widely used
to power remote telecommunication systems, for example, repeater stations. Repeaters are
Power supply fields & grid complexity
Single consumers
& load groups
Solar (PV)
Solar thermal
Wind
Hydro
Oil, gas, biomass
Storage needs
Minute
consumers
Solar
homes
Stand-alone
systems
Supply of small and
medium loads
DC/...48 V 1~/230 V 3~/400 V
Hybrid technology
Isolated grids
Local power supply
3~/20 kV
Interconnected
grids
Regional power supply
Trans
national
grid
Trans-reg.
power sup.
3~/110 ... 380 kV
Voltage form and level
10 W 100 W 1 kW 10 kW 100 kW 1 MW 10 MW 100 MW
Power ranges
Figure 17.8 Classification of power supply technology for electrification with renewable
energy – energy sources, application classes and trends (Source: ISET, Kassel [13])