Looking to the future, there are several challenges that electricity networks will face: prosperity, global sustainable growth and security. The electricity industry situation is complex because resources worldwide are becoming scarce and the need for sustainable growth is important. Dealing with this challenge led to the foundation of micro-grids. The classical 'micro-grid' defines a mix of distributed energy resources (DER) capable of providing sufficient and continuous energy to a significant portion of the internal demand. Transmission system friendly micro-grids is a novel concept to encourage the power electronic converters to provide grid services and functionalities in line with new standards such as IEEE 1547- 2018. This paper presents a method for reducing losses by injecting reactive power from the grid-connected DER. The methodology is developed in Python and the system is modelled in DIgSILENT PowerFactory. The paper includes numerical results of the proposed methodology to show the suitability of the proposed concept.

Looking to the future, there are several challenges that the electricity networks will face: prosperity, sustainable growth, global, and security. The electricity industry situation is complex because resources across the world are becoming scarce and the need for sustainable growth is increasingly important. The evolution of a decarbonized economy involves three main aspects: developing energy efficiency measures, developing renewable energy capabilities, and dealing with adaptation needs arising due to climate change. However, the massive integration of generation technologies based on power electronic converters (PECs) are producing adverse effects for transmission system operators (TSOs) and distribution network operators (DNOs). The TSOs and DNOs are witnessing this loss of control of their systems and are exploring the possibility of requiring these new generators to adopt a set of functionalities to help mitigate the side effects caused by the converter/renewable generation. The concept of power converter-based microgrids (MGs) provides vast opportunities for many service providers who can help operate the transmission system. The classical concept of an MG defines it as a set of interconnected distributed energy resources (DERs) capable of providing sufficient and continuous energy to a significant portion of internal load demand. The MG concept has been extraordinary explored in the literature, especially with regard to the connection to the traditional alternating current (AC) system. However, the most recent development of grid-friendly or smart-converters allows the PECs to perform additional tasks that could help the TSO with operational problems, such as voltage control, low short-circuit currents, etc. This chapter is dedicated to introducing the concept of grid-friendly or smart-converters and how they can be used to create fully controllable MGs able to provide auxiliaries services to the transmission system: the so-called “transmission system-friendly microgrid.” This is an AC MG fully dominated by power-converter technologies, where the local and wide control is used in the mode of a power converter, which enables novel operational functions, for example, reactive power provision to enable voltage control. This chapter presents the concept of grid-friendly or smart-converters and their main capabilities. Their functions are enhanced by a wide-area control and the concept is a transmission system-friendly MG. The chapter includes numerical results of the proposed control algorithm and its implementation using Python and simulations using DIgSILENT PowerFactory to demonstrate the suitability of the proposed transmission system-friendly MG.