At present, the structure of power systems is greatly changing due to the penetration of decentralized generations. Although they encompass a high flexibility potential, their large-scale penetration interferes with t...At present, the structure of power systems is greatly changing due to the penetration of decentralized generations. Although they encompass a high flexibility potential, their large-scale penetration interferes with the power system operation at all voltage levels. To get rid of this flaw and exploit their flexibility, different concepts like Virtual Power Plants, Microgrids and Cellular Approach have been introduced but still no solution is in sight. Under these conditions, it seems quite intriguing to find out whether these concepts are likely to offer a complete solution or not. This paper presents ten criteria to assess the complete Smart Grid solution and introduces a comprehensive evaluation system based on cloud-charts. The paper looks into the already existing solutions, which are respectively based on Virtual Power Plants, Microgrids and Cellular Approach concepts. The investigations have shown that none of these solutions meets all criteria necessary for a complete Smart Grid solution. Even a combination of different criteria fails to yield the desired results.展开更多
The major challenge to increase the decentralized generation share in distribution grids is the maintenance of the voltage within the limits. The inductive power injection is widely used as a remedial measure. The mai...The major challenge to increase the decentralized generation share in distribution grids is the maintenance of the voltage within the limits. The inductive power injection is widely used as a remedial measure. The main aim of this paper is to study the effect of the reactive power injection (by what-ever means) on radial grid structures and their impact on the voltage of the higher voltage-level grids. Various studies have shown that, in addition to the major local effect on the voltage at the injection point, the injection of the reactive power on a feeder has a global effect, which cannot be neglected. The reactive power flow and the voltage on the higher voltage level grid are significantly affected. In addition, a random effect is introduced by the DGs which are connected through inverters (using wind or PVs). Although their operation is in accordance with the grid code, a volatile reactive power flow circulates on the grid. Finally, this study proposes the implementation of the “Volt/var secondary control” interaction chain in order to increase the distributed generation share at every distribution voltage level, be it medium or low voltage, and at the same time to guarantee a stable operation of the power grid. Features of Volt/var secondary control loops ensure a resilient behavior of the whole chain.展开更多
文摘At present, the structure of power systems is greatly changing due to the penetration of decentralized generations. Although they encompass a high flexibility potential, their large-scale penetration interferes with the power system operation at all voltage levels. To get rid of this flaw and exploit their flexibility, different concepts like Virtual Power Plants, Microgrids and Cellular Approach have been introduced but still no solution is in sight. Under these conditions, it seems quite intriguing to find out whether these concepts are likely to offer a complete solution or not. This paper presents ten criteria to assess the complete Smart Grid solution and introduces a comprehensive evaluation system based on cloud-charts. The paper looks into the already existing solutions, which are respectively based on Virtual Power Plants, Microgrids and Cellular Approach concepts. The investigations have shown that none of these solutions meets all criteria necessary for a complete Smart Grid solution. Even a combination of different criteria fails to yield the desired results.
文摘The major challenge to increase the decentralized generation share in distribution grids is the maintenance of the voltage within the limits. The inductive power injection is widely used as a remedial measure. The main aim of this paper is to study the effect of the reactive power injection (by what-ever means) on radial grid structures and their impact on the voltage of the higher voltage-level grids. Various studies have shown that, in addition to the major local effect on the voltage at the injection point, the injection of the reactive power on a feeder has a global effect, which cannot be neglected. The reactive power flow and the voltage on the higher voltage level grid are significantly affected. In addition, a random effect is introduced by the DGs which are connected through inverters (using wind or PVs). Although their operation is in accordance with the grid code, a volatile reactive power flow circulates on the grid. Finally, this study proposes the implementation of the “Volt/var secondary control” interaction chain in order to increase the distributed generation share at every distribution voltage level, be it medium or low voltage, and at the same time to guarantee a stable operation of the power grid. Features of Volt/var secondary control loops ensure a resilient behavior of the whole chain.
