A three phase photovoltaic power system connected to the MV network: behaviour during voltage dips

Abstract

The presence of Distributed Generation (DG) in the distribution network is increasing and represents one of the most important research areas. Several reasons have forced this increase like the possibility to use renewable resources reducing the fossil fuels use with environmental and energy benefits. The paper deals with the results of a study performed by RSE, in the frame of the Research Fund for the Italian Electrical System, focused on the behaviour during voltage dips of a "DG system", consisting in a Photovoltaic generator (PV) connected to the network with three phase Voltage Source Inverter (VSI).

Permanent magnet wind generators: control strategies to manage voltage unbalances

“…The diode bridge rectifier generates an unregulated DC voltage from the AC outputs of the PMSG which supplies the boost converter. This latter is controlled with a hysteresis band modulation [3] and sets the current extracted from the generator. The DC-DC converter output voltage is the DC input of the VSI which regulates the voltage across the capacitor by controlling the power injected into the distribution network through the LV/MV transformer.…”

“…This control approach, whose block scheme representation is shown in Figure 2, is often adopted in other type of distributed generators which require power electronics as interface with the distribution network [3,5].…”

Fault Ride Through strategies for Permanent Magnets Wind Generators

“…Other control approaches have analogous behaviorsThe inverter DC voltage increases, as shown inFig. 7, even though the boost current set-point is modified according to(3). The use of the damping chopper allows maintaining the voltage within a specified range, between 1300 V and 1350 V in the considered example.…”

“…In a probable scenario of further increase of PMSG, a strategy to manage generators in case of voltage dips, alternative to the present practice of disconnecting DG from the network, should be adopted. Since present VSIs are not designed for having Fault Ride Through (FRT) capabilities, new hardware and control solutions must be adopted [2], [3]. This paper focuses on possible control schemes and control strategies for a wind power PMSG, optimized for the FRT of balanced and unbalanced voltage dips.…”

Simulation model of a protection scheme for active distribution networks

“…where I N is the rated current, V N the rated voltage and k≥2 [7][8][9][10]. The employed model does not take into account the presence of power electronic switches.…”