Effiziente statische Spannungshaltung in Verteilungsnetzen mit innovativen Blindleistungsverfahren

Meyer-Vomberg, Marian; Ulbig, Andreas (Thesis advisor); Engel, Bernd (Thesis advisor)

Aachen : RWTH Aachen University (2023)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023

Abstract

This thesis deals with static voltage stability with reactive power control in distribution grids. A new, decentralised reactive power control method is presented, which can reduce the inverter and grid losses caused by reactive power by 70-90 % compared to the state of the art control. The control method has the same effectiveness with regard to the hosting capacity. The reduced losses correlate with significant economic savings for grid and plant operators. The developed reactive power method is called Q(U(P)). Depending on the local active power feed-in, a voltage limit is determined to which the voltage at the grid interconnection point is regulated by the inverter using an integral controller block. The new method is compared with the state of the art Q(U) characteristic according to VDE AR-N 4105 and a method called cosφ(P, U) taken from the scientific literature. The cosφ(P, U) method is based on the classic cosφ(P) control, but at a low local voltage the reactive power is attenuated. The three methods are decentralised reactive power controls that are implemented on inverters for photovoltaic generators. The integration potential is determined for the three methods depending on the parameterisation. An identical dependency of the integration potential on the voltage parameterisation is found for all inverter operating ranges investigated. At high voltages at the grid interconnection point, the integration potential can be increased by 40 % by reactive power methods. The methods are similarly effective, since further restrictions such as the loading capacity of lines and transformers have a limiting effect. Differences in the voltage management are therefore not relevant in practice. In terms of efficiency, there are major differences between the methods. With an identical hosting capacity, the grid losses caused by reactive power can be reduced by 70-90 % by using Q(U(P)) instead of Q(U) as a control method. The efficiency of voltage regulation using decentralised reactive power cannot be significantly improved in low voltage grids any further. Even with the usage of communication technology improvements are marginal.

Institutions

• Chair of Active Energy Distribution Grids [614010]