This paper presents a noninvasive online parametric identification of three-phase AC power impedances to assess small-signal stability of grid-tied inverter systems by using well-known impedance-ratio-based stability criteria. The identification technique is integrated into the control of an existing grid-tied inverter for the estimation of wide bandwidth AC grid impedances, on top of its original power conversion function. This is accomplished in practice by injecting a short-time small-signal Pseudo Random Binary Sequence (PRBS), a digital approximation of white noise which is wide bandwidth in nature, on the inverter control loop so that all frequencies of interest at the impedance measurement point can be excited at once. Then, digital processing is performed in the integrated control platform where the parametric AC grid impedance is extracted from the measurement of voltage and current over the length of PRBS injection. Moreover, a procedure on how to identify the output impedance of the inverter is deployed so that the parametric source and load impedances can be used to verify the system stability by means of the generalized Nyquist stability criterion. The technique is validated via Hardware In the Loop (HIL) real-time simulation. The present work focuses on the identification of balanced three-phase AC impedances in dq reference frame and a dq diagonal-dominant stability analysis which is typical of LV Distribution Grids.

Modern distribution grids are complex systems that need advanced management for their secure and reliable operation. The Information and Communication Technology domain today offers unprecedented opportunities for the smart design of tools in support of grid operators. This paper presents a new philosophy for the digitalization and automation of distribution grids, based on a modular architecture of microservices implemented via container technology. This architecture enables a service-oriented deployment of the intelligence needed in the Distribution Management Systems, moving beyond the traditional view of monolithic software installations in the control rooms. The proposed architecture unlocks a broad set of possibilities, including cloud-based implementations, extension of legacy systems and fast integration of machine learning-based analytic tools. Moreover, it potentially opens a completely new market of turnkey services for distribution grid management, thus avoiding large upfront investments for grid operators. This paper presents the main concepts and benefits of the proposed philosophy, together with an example of field implementation based on open source components carried out in the context of the European project SOGNO.

The interconnection of power systems in conjunction with faster dynamics, caused by power electronics, increases the complexity of power system simulations for future grids. We propose an open platform as a solution which supports several important features. Grid models are stored in the Common Information Model (CIM) and the platform presents a uniform interface to several commercial and non-commercial Digital Real-time Simulator (DRTS) which can be used in parallel for co-simulation. A web-based interface is used to promote collaboration between research groups during planning and execution of simulation scenarios. Besides, this solution is designed for real-time simulation which allows the integration and testing of hardware components. Several components of the proposed platform have already been used for experiments and are available as open-source.

In future all-electrical ships with Medium Voltage DC distribution, the power system stability can be jeopardized by the presence of constant power loads, due to the negative impedance characteristic of their tightly regulated converters. In order to solve this problem we apply backstepping as a nonlinear control technique to the converter interfacing the generation side and which supplies the bus. In this work we demonstrate two versions of backstepping, which are compared to a centralized linearizing state feedback controller taken from literature.

Smart grids evolve rapidly towards a system that includes components from different domains, which makes interdisciplinary modelling and analysis indispensable. In this paper, we present a cosimulation architecture for smart grids together with a comprehensive data model for the holistic representation of the power system, the communication network, and the energy market. Cosimulation is preferred over a monolithic approach since it allows leveraging the capabilities of existing, well‐established domain‐specific software. The challenges that arise in a multidomain smart grid cosimulation are identified for typical use cases through a discussion of the recent literature. Based on the identified requirements and use cases, a joint representation of the smart grid ecosystem is facilitated by a comprehensive data model. The proposed data model is then integrated in a software architecture, where the domain‐specific simulators for the power grid, the communication network, and the market mechanisms are combined in a cosimulation framework. The details of the software architecture and its implementation are presented. Finally, the implemented framework is used for the cosimulation of a virtual power plant, where battery storages are controlled by a novel peak‐shaving algorithm, and the battery storages and the market entity are interfaced through a communication network.

Real-time simulation is an increasingly popular tool for product development and research in power systems. However, commercial simulators are still quite exclusive due to their costs and they face problems in bridging the gap between two common types of power system simulation, conventional phasor based, and electromagnetic transient simulation. This work describes recent improvements to the open source real-time simulator DPsim to address increasingly important use cases that involve power electronics that are connected to the electrical grid and increasing grid sizes. New power electronic models have been developed and integrated into the DPsim simulator together with techniques to decouple the system solution, which facilitate parallelization. The results show that the dynamic phasors in DPsim, which result from shifted frequency analysis, allow the user to combine the characteristics of conventional phasor and electromagnetic transient simulation. Besides, simulation speed up techniques that are known from the electromagnetic domain and new techniques, specific to dynamic phasors, significantly improve the performance. It demonstrates the advantages of dynamic phasor simulation for future power systems and the applicability of this concept to large scale scenarios.