Photovoltaic inverter low frequency oscillation

Why do inverters oscillate in a low-voltage grid?

The value of the virtual resistance can also be a source of instability; low values will induce high-frequency synchronous oscillations (also studied in ), while high values will induce subsynchronous ones. The oscillation mode originating from the power control has relatively low damping for inverters connected to low-voltage grids.

What causes a low-frequency oscillation in an inverter?

However, most challenging oscillations are low-frequency oscillations induced by coupling interaction between the outer loop controller and PLL (Phase-Locked Loop) when the inverter is connected to a weak grid.

Do PV inverters influence small-signal stability?

Another large body of research studies, especially in the past 10 years, has focused on the application of power oscillation damping (POD) control implemented in photovoltaic (PV) inverters. This paper aims to provide a comprehensive review of the utilization of PV inverters for influencing the small-signal stability of power systems.

Can a photovoltaic station damp a power oscillation?

This paper presents an analysis of renewable energy plants, in particular photovoltaic stations, on damping of these power oscillations. Achieving such damping function is possible via upgrading the automatic control system of photovoltaic stations by using a synthetic inertia block and the possibilities of the “underload” mode.

Why do PV inverters have a weak grid?

This paper presents a small signal stability analysis to assess the stability issues facing PV (photovoltaic) inverters connected to a weak grid. It is revealed that the cause of the transient instabilities, either high-frequency or low-frequency oscillations, is dominated by the outer control loops and the grid strength.

Why are low-frequency oscillations a problem in electric power systems?

The development of electric power systems determines the growing probability of low-frequency oscillations, which can be reason of system faults. Traditionally, the task of damping low-frequency oscillations is assigned to synchronous generators, by appropriate setting of the automatic voltage regulator parameters.