Distributed Small-Signal Stability Conditions for Inverter-Based Unbalanced Microgrids

Nandanoori, Sai Pushpak; Kundu, Soumya; Du, Wei; Tuffner, Francis K.; Schneider, Kevin P.

doi:10.1109/pesgm46819.2021.9638102

Cited by 4 publications

(7 citation statements)

References 32 publications

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“…Finally, we calculate efficiently the maximal droop coefficient for which these safety admissible controls exist. As such, this paper provides novel design guidelines for the droop control parameters, extending the literature on stability-informed droop settings, e.g., [6], [8], [9], and the references therein. We use SOS programming to solve the safety verification problems, and illustrate the algorithm via numerical simulations.…”

Section: Introductionmentioning

confidence: 88%

“…Remark 1: Note that the problem of identifying the maximal droop for stability analysis is relatively well studied in the literature (see, for instance, [6], [8], [9]). However, as a novel contribution of this paper, we propose a method to identify maximal droop values for safety verification.…”

Section: Maximal Droop For Robust Control Invariancementioning

confidence: 99%

“…Many recent efforts have addressed this need via, for example, stability and security-constrained optimization [3], [5], [7], identification of local and distributed parametric stability conditions [6], [8], [9], etc. The distributed identification of stability conditions are particularly interesting since these fit well into a multi-ownership models of microgrid resources, and facilitate hierarchical and plug-andplay operations [10].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Distributed Transient Safety Verification via Robust Control Invariant Sets: A Microgrid Application

Bouvier¹,

Nandanoori²,

Ornik³

et al. 2022

Preprint

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Modern safety-critical energy infrastructures are increasingly operated in a hierarchical and modular control framework which allows for limited data exchange between the modules. In this context, it is important for each module to synthesize and communicate constraints on the values of exchanged information in order to assure system-wide safety. To ensure transient safety in inverter-based microgrids, we develop a set invariance-based distributed safety verification algorithm for each inverter module. Applying Nagumo's invariance condition, we construct a robust polynomial optimization problem to jointly search for safety-admissible set of control set-points and design parameters, under allowable disturbances from neighbors. We use sum-of-squares (SOS) programming to solve the verification problem and we perform numerical simulations using grid-forming inverters to illustrate the algorithm.

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Section: Introductionmentioning

confidence: 88%

Section: Maximal Droop For Robust Control Invariancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distributed Transient Safety Verification via Robust Control Invariant Sets: A Microgrid Application

Bouvier¹,

Nandanoori²,

Ornik³

et al. 2022

Preprint

Self Cite

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“…(3), ( 4) are the droop characteristic equations where 𝜔 0 , V 0 are nominal angular frequency and voltage values corresponding to P 0 , Q 0 , and m p , n q are droop characteristics slopes which are FIGURE 3 The structure of VSI calculated from ( 5) and ( 6):…”

Section: Power Sharing Controllermentioning

confidence: 99%

Microgrid small‐signal stability analysis considering dynamic load model

Mahdavian

Ghadimi

Bayat

2021

IET Renewable Power Gen

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Microgrids suitable operation depends on the system's proper design, based on accurate component models. A complete model considering entire system dynamics is a vital necessity for a successful design. Using dynamic load in microgrid small-signal model results in a model that shows transient and steady-state dynamics, since designing a low-inertia system like microgrid need extra accuracy. In this paper, an inverter-based microgrid's small-signal model in islanded operation mode containing a dynamic load model has been achieved. The Exponential Recovery Load (ERL) model is presented here to study the dynamic behavior of load. Microgrid stability analysis has been carried out for both static and dynamic load models. To attain this goal, the entire component equations are obtained and linearized around an operating point, then the state-space model is formed and eigenvalues are derived. System stability condition has been investigated by plotting eigenvalues and root locus method. In the final step, a simulation on Matlab/Simulink is performed to show the microgrids operation in the presence of a static and dynamic load.

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“…This fact is recognized in various stability and security-constrained optimization formulations for microgrids, as exemplified in [4]- [6] and related works. On the other hand, this has also spurred the interest in deriving local and distributed stability conditions for the inverters, specified with respect to its control parameters [7]- [12], to facilitate the emergence of plug-andplay operations in microgrids and distribution networks [13], [14]. Unlike stability and stabilization, the concept of safety violations of node voltages, line currents and frequencies, especially during transients, leading to severe power quality issues and possible damages to the electrical equipment [5], [15] have been largely ignored in the literature.…”

Section: Introductionmentioning

confidence: 99%

Transient Safety Filter Design for Grid-Forming Inverters

Kundu¹,

Kalsi²

2020

Preprint

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Unlike conventional generators, inverter-based generation do not possess any rotational inertia. While grid-forming inverters can synthesize small (virtual) inertia via advanced feedback control loops, additional control mechanisms are needed to ensure safety and security of the power grid during transients. In this paper, we propose novel real-time safety-constrained feedback controllers ("safety filters") for droop-based (gridforming) inverters to ensure transient security of the grid. The safety filter acts as a buffer between the network operational layer and the inverter-control layer, and only lets those dispatch control signals pass to the inverter droop-controller, which are guaranteed to not violate the safety specifications (frequency, voltage, current limits). Using a distributed barrier certificates method, we construct state-inclusive bounds on the allowable control inputs, which guarantee the satisfaction of transient safety specifications. Sum-of-square programming is used to synthesize the safety filters. Numerical simulation results are provided to illustrate the performance of the proposed filter in inverter-based microgrids.

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Distributed Small-Signal Stability Conditions for Inverter-Based Unbalanced Microgrids

Cited by 4 publications

References 32 publications

Distributed Transient Safety Verification via Robust Control Invariant Sets: A Microgrid Application

Distributed Transient Safety Verification via Robust Control Invariant Sets: A Microgrid Application

Microgrid small‐signal stability analysis considering dynamic load model

Transient Safety Filter Design for Grid-Forming Inverters

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