Medium-voltage network planning with optimized power factor control of distributed generators

Distributed generation causes new challenges in medium voltage networks. Especially voltage stability is becoming an issue. Conventional planning measures, like network expansion, can be used to address this challenge, but they should be planned with great care due to their high costs. Power factor control of distributed generators is an alternative to such measures. Therefore it should also be considered in long term distribution network planning. It is the purpose of this paper to present a new approach for long term medium-voltage network optimization that integrates near optimal power factor control. The structural optimization is heuristic and based on a Delaunay triangulation in combination with an ant colony algorithm. Power factor control is predicated on dynamic programming. It is shown how near optimal results can easily be realized under German law with present technologies. A case study illustrates the impacts and advantages of an integrated planning approach. The integrated optimization resulted in network costs that are 2.5 % lower than the costs of the best topology found by conventional planning.