The “50.2 Hz” problem for photovoltaic power plants

Bucharest, April 27, 2012

The study commissioned by four network operators from Germany – “The effects of decentralized electrical energy generators on the network stability and proposals for fighting their effects” revealed the “50.2 Hz” problem.

This study was finalized in September 2011 and the German Ministry for the Environment together with the German Ministry of Economy recommended starting a retrofit process of approximately 9 GW of functioning photovoltaic power plants. The problem is generated by the necessity of disconnecting photovoltaic power plants from the network immediately at the moment that the network frequency exceeds 50.2 Hz.

Modern inverters are solving this problem by diminishing the power delivered proportionally with the increase of the network frequency. Inverters that cannot provide this function need to disconnect from the network in a manner that can provide the same effect, which leads to diminishing production of photovoltaic power plants, and implicitly to reduction in generated revenue.

The estimated cost for solving this problem is between 65 -175 million Euros.

Dan Cirstoc
Sales Manager
Siemens SRL