Grid services with PV-converters in distribution systems

Abstract

The most affected parts of the electrical power system in Germany are the distribution grids due to the rapid expansion of renewable energies. Most of these micro power plants e.g. photovoltaic systems feed into the low (LV) and medium (MV) voltage level. The voltage stability in these levels is thus much more complex and is partially violated in moments of strong feed-in. To reduce this negative impact the directive VDE-AR-N 4105 was specified that PV-inverters must provide reactive power instead of pure active power. This directive should however only be the beginning. In a smart grid, the asset inverter should be used much more intensively.In this paper it is demonstrated by power flow simulations with the data of a real distribution grid including PV-system feed-in that there are more possibilities but providing the reactive power for the distribution and voltage stability. It is illustrated that the use of the complete apparent power of the inverter is a more appropriate way to obtain the stationary stability of distribution grids. With this strategy in addition, the power loss can be influenced in LV-and MV-level and the power factor of the feed-in of the HV/MV-supplying transformer can be adjusted.Index Terms-Reactive power control, smart grids, photovoltaic cells, power system management.

Live Field Validation of an Islanded Microgrid Based on Renewables and Electric Vehicles

“…This objective is achieved by adopting the standard VDE-AR-N-4105 [24] and modifying the grid frequency as a function of the main battery State-of-Charge (SoC). Some examples of this standard's application can be observed in [27][28][29].…”

Low-voltage ride-through capability of cascaded H-bridge multilevel converters for large-scale photovoltaic power plants

“…Renewable energy sources are occupying an increasing share in the global power generation market. Among various renewable energy sources, the photovoltaic (PV) technology has been in the focus of many governments and, supported substantial subsidies has resulted a steep increase in the installed capacity [1]. Due to the increasing tendency of installed grid-connected photovoltaic power plants (GCPVPPs), there is a requirement to use advanced converter topologies in combination with optimized control structures in order to maximize the extracted power and reduce the losses and complying with grid code and standards [2]- [4].…”

Active/reactive power control of PV grid-tied NPC inverter using 3-D space vector modulation in abc coordinate

“…Due to the high penetration of installed photovoltaic power plants (PVPP) in the grid, new grid codes and standards are regulated in order to maintain the power quality and reliability of the power system. Consequently, PVPPs should be designed in order to inject the regulated active/reactive power to the grid during normal operation and also under grid faults [1], [2].…”