Following the global environmental trends renewable generation in European countries experienced a significant growth. Energy from non-dispatchable renewables has some unique properties, which need to be addressed when integrating renewable resources into the power network. Two of those unique properties are uncertainty and variability of generation.
At the beginning of the thesis we have focused on the problems that arise with integration of renewable generation into the power grid. Then we described the existing ancillary services, which are used by transmission system operator for the safe operation of the power grid. The main focus of this thesis is research of ancillary services, provided by renewable generation. Renewable resources have typically smaller installed power compared to conventional generation sources and are connected at the distribution network. Distributions networks were initially designed as passive with power flows going from transmission to the distribution network. If we wish to achieve high percentage of renewable generation then we will have to implement new ancillary services, which will support further integration of renewable generation. Conventional distribution networks have to be upgraded with smart grid concepts. We have also researched challenges for enhancing capabilities of solar and wind power plants in providing ancillary services.
We researched the effects of integrating renewable generation in Slovenia. We found out that due to substantial financial subsidies renewable generation in Slovenia increased significantly. Because of insufficient technical requirements for installation, currently installed renewable resources in Slovenia are not capable of providing ancillary services with fast response times. Renewable resources, currently connected at the distribution network could be suitable for provision of operating reserves. In the last chapter we researched different techniques of solving overvoltage mitigation in low voltage distribution networks. We developed new technique of integrated control for overvoltage mitigation using droop control and profit sharing between generators.