Power oscillation | In the last few years the power rating of PV power plants has risen very quickly to values reaching several hundred megawatts. This means there are hundreds, or even thousands, of inverters operating in parallel in these plants. Furthermore, these large-scale PV power plants are often built far away from cities and are therefore connected to the grid via long transmission lines. This leads to weak grid conditions in the power plants, and these conditions give rise to the risk of electrical instabilities within the plant, or instabilities of the plant within the grid. Roland Singer of Fraunhofer ISE explains how these electrical instabilities can be detected and counteracted.