Controle de microrrede baseado em frequência

Abstract

This paper proposes the concept of a new generation for emergency power systems, which are usually composed of a diesel generator coupled to a truck, used in the power distribution network to provide electricity to a customer (load) when some maintenance be done on the power grid. On the other hand since 2009 Germany has experienced an increase in the installation of photovoltaic solar energy through distributed generation. When the power utility maintains the low voltage electrical network that feeds a home equipped with photovoltaic system, it is disconnected from the grid by the protection system. However, the use of this photovoltaic system to feed the load can be exploited. In this work, an emergency power generating unit, consisting of a diesel generator and a battery bank with the respective converters supplying a continuous load, will be investigated, taking into account the use of the customer's photovoltaic system to contribute to the power supply. Thus, the system will operate isolated from the main power grid, categorizing itself as a microgrid operating in off-grid mode. To do this, it will be necessary to develop a frequency control so that the microgrid operates in an islanded mode. The battery, modeled as a voltage source, will adjust the voltage values of the microgrid. Furthermore, controllable circuit breakers, depending on the frequency of the mains, have been modeled for both the battery and the diesel generator. The DIGSilent Powerfactory software was used to model the studied microgrid and perform the computational simulations, which are static. Applying a frequency pulse to the microgrid, with sub- and overfrequency variations, it was evaluated how the elements of the microgrid will react, according to the control strategy chosen. Through these simulations, it has been discovered that frequency can be used as an important value for energy management in the context of microgrids.