Synchronization of the Parts of Electrical Networks with Distributed Energy Sources After Emergency or Accident-Prevention Separation

Passive electric distribution networks are being transformed into active ones, which are low-capacity power plants, owing to the integration of small generating facilities and local power supply systems based on them [local intelligent power systems (Minigrid) and active energy complexes (AEC)]. This transformation requires the development of effective decentralized control systems for the modes of such networks, since the conventional centralized management is expensive. This paper presents the results of a study conducted on the possibilities of decentralized synchronization of the active parts of an electrical network that remain operational in the isolated mode, when restoring the integrity and normal mode of the network after emergency or accident-prevention separation. The complexity of the synchronization lies in the need to perform it on uncontrolled network switching devices (switches, reclosers) that are remote from power plants, with the quasisteady-state parameters of post-emergency modes, which, in general, significantly deviate from the nominal ones. This paper proposes a method for a decentralized control of the synchronization of small generating facilities of the separated parts of an electric network and of the network switching devices, which ensures, with a special control of the excitation of generators and power (frequency), the scanning of the synchronization conditions, and a successful synchronization without data exchange between the control devices involved in the process. The proposed method is multi-agent by type and based on the independent behavior of each device operating according to common rules. The operability of the method was tested on a physical model of power systems.