German PV plants - an interesting problem

[Yo_Mama]

http://www.germanenergyblog.de/?p=7313#more-7313

This is not political, etc. It's an interesting technical problem about stabilizing grid voltage. The older standards for German PV plants required that the plant automatically stop feeding electricity to the grid when the grid was running above normal capacity:

Until the introduction of temporary voluntarily applicable rules set by VDE in spring 2011, power generators connected to the low-voltage grid – including PV systems – were required to disconnect from the public grid as soon as the grid frequency exceeded 50.2 Hz. During normal operations (50.0 Hz), this level has so far not been reached, and was not likely to be reached.

The suggested alternatives are in the linked article but include varying the set points for disconnect and scrolling feed-in power inversely to the grid frequency. This is not supposed to affect small installations such as household. The problem is that installed capacity has reached the point at which this could crash the grid, because if the frequency hits the discriminant, all of a sudden a whole bunch of generation is going to drop out.

This is just one example of why we should watch what Germany is doing closely!

[kristopher]

1. .

"Retrofitting is being recommended for all PV systems with a capacity of over 10 kWp that started operating after 1 September 2005. According to the study, retrofitting would in the vast majority of cases consist of a software update or a change of the parameter settings of the solar inverter. It is recommended to be carried out between 2012 and 2014 on around 315,000 mid- to large-sized solar power systems that are connected to the low-voltage grid. Thus, small roof-mounted systems on single-family homes would not be required to undergo retrofitting."

[diane in sf]

2. Good info.