Performance evaluation of secondary control policies with respect to digital communications properties in inverter-based islanded microgrids

A key challenge for inverted-based microgrids working in islanded mode is to maintain their own frequency and voltage to a certain reference values while regulating the active and reactive power among distributed generators and loads. The implementation of frequency and voltage restoration control policies often requires the use of a digital communication network for real-time data exchange (tertiary control covers the coordi- nated operation of the microgrid and the host grid). Whenever a digital network is placed within the loop, the operation of the secondary control may be affected by the inherent properties of the communication technology. This paper analyses the effect that properties like transmission intervals and message dropouts have for four existing representative approaches to secondary control in a scalable islanded microgrid. The simulated results reveals pros and cons for each approach, and identifies threats that properly avoided or handled in advance can prevent failures that otherwise would occur. Selected experimental results on a low- scale laboratory microgrid corroborate the conclusions extracted from the simulation study.Peer ReviewedPostprint (author's final draft

De quelques éléments décoratifs à la crypte de Saint-Maixent

Miret Rull Enric. De quelques éléments décoratifs à la crypte de Saint-Maixent. In: Cahiers de civilisation médiévale, 1e année (n°4), Octobre-décembre 1958. pp. 495-499

Aragón. Cuatro ensayos

Miret Rull Enric. Aragón. Cuatro ensayos. In: Cahiers de civilisation médiévale, 8e année (n°31-32), Juillet-décembre 1965. pp. 415-418

Aragón. Cuatro ensayos

Miret Rull Enric. Aragón. Cuatro ensayos. In: Cahiers de civilisation médiévale, 8e année (n°31-32), Juillet-décembre 1965. pp. 415-418

Séminaire de l'art roman en Saintonge

Miret Rull Enric, Swiechowska Aleksandra, Crozet René. Séminaire de l'art roman en Saintonge. In: Cahiers de civilisation médiévale, 1e année (n°1), Janvier-mars 1958. pp. 102-103

Chronique

Semmler Josef, Miret Rull Enric, Chélini Jean, Crozet René, Toth Barnabas. Chronique. In: Cahiers de civilisation médiévale, 9e année (n°34), Avril-juin 1966. pp. 263-274

Chronique

Semmler Josef, Miret Rull Enric, Chélini Jean, Crozet René, Toth Barnabas. Chronique. In: Cahiers de civilisation médiévale, 9e année (n°34), Avril-juin 1966. pp. 263-274

Communication-aware consensus for frequency restoration in islanded microgrids

MicroGrids (MGs) include spatially distributed generation (DG) systems and loads that may require operating autonomously in islanded mode. The operation of islanded MGs can benefit from consensus theory and practice, which are the foundations of distributed control. One of the main features of consensus strategies is that they rely on a cooperative scheme where inverters are required to communicate with their neighbors. Therefore properties of the communication network become fundamental. The contribution of this paper is twofold. First, it analyses the impact that communication properties such as transmission interval and message dropouts have in a given consensus-based frequency restoration strategy. Second, new design guidelines for the consensus policy are derived considering the communication dynamics as an opportunity for performance improvement.Peer ReviewedPostprint (published version

Performance analysis of frequency restoration for parallel voltage source inverters connected with a realistic communication channel

A topic of interest within the microgrid (MG) community is to achieve accurate sharing of active and reactive power among voltage source inverters (VSI) working in parallel while keeping the voltage frequency and amplitude stable, and close to a given reference. This problem has been mainly solved by the so-called frequency and voltage droop controllers that are local control loops implemented in each VSI. However, since they introduce a frequency and amplitude deviation, a secondary integral-like control loop using a communication system is usually deployed to enable each VSI to cancel the deviations. This paper evaluates two secondary control implementations of the frequency restoration with respect to properties of the communication system. Networked control applications are subject to known problems that are inherent to the use of a communication system such as message losses or varying sampling/transmission intervals, to name a few. The performance analysis reveals that control policies should be designed accounting also for the properties of the communication system. Otherwise, unexpected results violating the control specifications may appear.Peer Reviewe

Communication-aware consensus for frequency restoration in islanded microgrids

MicroGrids (MGs) include spatially distributed generation (DG) systems and loads that may require operating autonomously in islanded mode. The operation of islanded MGs can benefit from consensus theory and practice, which are the foundations of distributed control. One of the main features of consensus strategies is that they rely on a cooperative scheme where inverters are required to communicate with their neighbors. Therefore properties of the communication network become fundamental. The contribution of this paper is twofold. First, it analyses the impact that communication properties such as transmission interval and message dropouts have in a given consensus-based frequency restoration strategy. Second, new design guidelines for the consensus policy are derived considering the communication dynamics as an opportunity for performance improvement.Peer Reviewe