In Germany, the majority of renewable generation is connected to the distribution network level which includes low-voltage up to high-voltage (HV) level. The infeed of this power can cause an unacceptable voltage rise. The required additional network equipment, e.g. lines, generates reactive power if they run idle. Reactive power is also required to transport this power in the transmission network. If distribution system operators (DSO) control the reactive power locally, the decentralised generators (DGs) can contribute to reduce the mentioned problems. In this study, a concept of a reactive power management system is presented as it is developed by a joint work of five DSO in Germany. Results of the practical implementation of the first stage are demonstrated. Algorithms to improve the system in a second stage are presented. DGs in the HV level can be used to compensate the reactive power from the lower-voltage levels and even improve the balance to the transmission system. An overall optimisation combined with a local voltage limiting functionality essential to use a high portion of the potential by still keeping the network in a safe operating condition.