SYNOPTRA enables you to plan overhead lines that take care of the following optimization criteria:

• Visibility
• Costs
• Approval ability

SYNOPTRA uses a probabilistic method to optimize the lines. This method - called "genetic algorithms" - is based on the evolutionary process of "survival of the fittest". Starting point of this process is a population (i.e. a certain number) of overhead lines that is randomly created - but each of them representing a possible solution to the problem! Better individuals (i.e. overhead lines) survive with higher probability. Some of them are crossed-over, other are mutated leading to a new population of overhead lines. This process is repeated until no further improvements are visible - this could be the case after approx. 100 generations.

Consideration of different optimisation criteria complicate the problem. This is solved using modern and largely accepted methods for multiobjective optimisation that have been developed during Pascal Rheinert's master thesis and are now part of SYNOPTRA. In the following the optimisation criteria are explained in more details:

Visibility

The visibility of an overhead line during the optimisation process is calculated as the sum of total visibilities (see [Zewe]Rainer Zewe
Einfluß von Freileitungen auf das Landschaftsbild
Dissertation am Lehrstuhl für Energieversorgung
Universität des Saarlandes, 1995 ) of the pylons. Unit of visibility is "sterad" [sr]. The lower this value is the less visible is a pylon.

Costs

The costs of an overhead line are based on several components: Costs of the pylons (groundwork, steel, costs of construction) and costs of the conductors (depending on number of conductors and thickness). All these parameters are taken into account during the optimisation.

Approval ability

The better the planner succeeds in avoiding inhabited areas or nature reserves and in tracing along existing (power) lines, streets or railways the higher is the chance to get the approval for building the overhead line. These factors are accumulated under "approval ability".

Final optimisation

As already stated several optimisation criteria have to be considered at once. The weight of each criterion can freely be defined by the planner. In the process of final optimisation the algorithm searches for variants that cope best with all three criteria - by taking into account the formerly defined weights. By referencing to the initially determined optimized values it is now possible to sum up the values of each optimisation criterion which can additionally be weighted by the importance of the criterium for the planning process.