CONTROL OF VIRTUAL POWER PLANTS

Abstract

The power generation sources are mostly non-renewable in the conventional set up which are both cost ineffective and have larger carbon footprint on the atmosphere. These inherent disadvantages of the conventional power generation sources are forcing a historic transition in the power grid were numerous renewable energy dependant sources are being incorporated into the grid. Hence the Distributed Generation (DG)' is introduced in the modern power grid - a smart grid. The DG sources in the smart grid are controlled by using the concept of virtual power plant (VPP) or the Microgrid. Both these concepts viz. VPP and the Microgrid are challenged with the problem of the flow of active and reactive power between their comprising DOs and the control of this flow of power. This report analyzes this problem in the scenario of VPP and proposes a novel control scheme to control the output active and reactive power of three phase average voltage model based voltage source inverters (AVM-VSI) operating in the VPP environment. The proposed controller accurately controls the active and reactive power injection to the Power Grid from the VPP at the point of coupling of the VPP to the Grid without taking any information from the coupling bus, thus proving to be economical. The proposed controller is also shown to independently control the active and reactive power. This work also takes into account the intermittent nature of the renewable energy DG sources and for that purpose incorporates a storage battery via a non-isolated bidirectional DC-DC converter (NBDC). The controller of the NBDC ensures that the contracted amount of active power to be supplied to the grid by the VPP is always available in right quantity irrespective of the generation from the DG.