Environmental Engineering Reference
In-Depth Information
•
Dynamic simulation
allows transients and stability to be examined. This is particularly
important in the design of transmission systems. The modelling has to include the dynamic
characteristics of the generators and their associated control systems.
5.6.2 A Particular Case
The one-line diagram of the Icelandic national power system shown in Figure 5.12 is powered
mostly by renewable energy, primarily hydro, but with an increasing contribution from geo-
thermal. The generators are indicated by the symbol, while the loads are shown as triangles.
In practice, these loads are the bulk supply substations that feed power to the distribution
networks, but for now they will be thought of as simple point loads. The thick horizontal
lines are
nodes
(also known as
buses
) and, although they have a fi nite length in the diagram,
electrically they are just connection points: they have zero length and zero impedance. The
thinner lines in the diagram are the actual transmission lines and each one has a fi nite imped-
ance, which may be estimated from the line characteristics and its length. The system uses a
mix of 220, 132 and 66 kV and the transformers connecting these are indicated by the usual
symbol.
In the design and operation of a power system it is important to know the power fl ows,
both active and reactive, the voltages (which will normally differ slightly from the nominal
Glerárskógar
Geiradalur
Mjólká
Rangárvellir 66 kV
Laxá 66 kV
Hrútatunga
Blanda
Rangárvellir
Hryggstekkur
Vatnshamrar
Laxárvatn
Varmahlíð
Krafla
Brennimelur 132 kV
Hrauneyjarfoss
Brennimelur 220 kV
Teigar-
horn
Sigalda
Sog 220 kV
Geitháls 220 kV
Búrfell1
Sigalda 132 kV
Geitháls
Sog 132 kV
Hamra-
nes
Prestbakki
Hólar
Figure 5.12
Single-line diagram of the Icelandic national power system. (Reproduced from Egill B.
Hreinsson, www.hi.is/∼ egill/rit/estonia99.pdf )
