Large-Signal Stability Analysis for Islanded Microgrids Based on Inner Control Loops Approach

Ndiwulu, Guy Wanlongo; Jaeger, Emmanuel De; Lusala, Angelo Kuti; Matalatala, Michel

doi:10.1109/powerafrica52236.2021.9543101

Cited by 2 publications

(9 citation statements)

References 7 publications

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“…+ , total load loss total load loss (31) where P load is the total active power load demand and Q load the total reactive power load demand.…”

Section: Problem Formulationmentioning

confidence: 99%

“…An improved backward/ forward sweep approach was proposed in many studies. [29][30][31] These methods have high computational efficiency and good solution accuracy, but they are only suitable for radial distribution and weakly meshed systems with singular power sources and could be subjected to convergence issues when used in multisource microgrids. 3 This method also considers a slack node and other nodes as PQ nodes which is an invalid assumption in IM.…”

Section: Introductionmentioning

confidence: 99%

“…This assumption is not practicable as the DG units are generally of micro sources and none have the capability to act as an infinite bus to hold the network frequency and its local voltage constant. An improved backward/forward sweep approach was proposed in many studies 29–31 . These methods have high computational efficiency and good solution accuracy, but they are only suitable for radial distribution and weakly meshed systems with singular power sources and could be subjected to convergence issues when used in multisource microgrids 3 .…”

Section: Introductionmentioning

confidence: 99%

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Steady‐state operating points of islanded virtual synchronous machine microgrid

Kamilu,

Beck

2024

Energy Science & Engineering

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Before starting stability analysis of the multivirtual synchronous machine (n‐VISMA) power system, it is necessary to obtain the steady‐state operating points (SSOPs) of all dynamic nodes in the network. Modified traditional iterative schemes using the concept of droop bus technique in an islanded microgrid are not feasible for load flow analysis of VISMA microgrid incorporating non‐control dynamics. This paper proposes closed‐form steady‐state, fundamental‐frequency models for islanded VISMA microgrids using the concept of virtual swing buses. In this technique, the virtual internal buses of all VISMAs in the network are governed by the swing equation. The voltage at all buses is variable except the virtual buses in which the pole wheel voltages are prespecified. The algorithm was extended by a droop control localized to each VISMA. The suitability of the proposed algorithm to obtaining SSOPs of VISMA was tested on IEEE‐9 bus system with VISMA replacing electromechanical synchronous machines and also on a low‐voltage distribution system. To validate the applicability of the proposed algorithm and prove its accuracy, the case study systems were also modeled in the SIMULINK environment for detailed time domain analysis. The algorithm was found to be computationally effective for a load flow analysis of the VISMA microgrid. The results also reveal that the addition of external droop control improves the frequency stability of the system.

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“…+ , total load loss total load loss (31) where P load is the total active power load demand and Q load the total reactive power load demand.…”

Section: Problem Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Steady‐state operating points of islanded virtual synchronous machine microgrid

Kamilu,

Beck

2024

Energy Science & Engineering

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“…Two group experiments were performed: Group A, the power variation of CPLs from 40 W to 80 W, and Group B, the power variation of CPLs from 40 W to 100 W. Obviously, Group A's parameters met the condition (24), while Group B's parameters did not (24).…”

Section: Experimental Verification Of 3d Ras and Large Signal Stabili...mentioning

confidence: 99%

“…In [14,23], mixed potential function(MPF) is used to derive a DC Microgrid's large signal stability requirement and interpret the relationship between system parameters and stability. The voltage frequency and current control mechanisms of isolated microgrids that are fed by controlled inverters are investigated in [24], and the large signal stability of the system was investigated. In [25], the research object is the AC/DC hybrid microgrid, with a particular focus on developing the Liapunov function and analyzing the system's large signal stability.…”

Section: Introductionmentioning

confidence: 99%

Large Signal Stability Criteria Combined with a 3D Region of Asymptotic Stability Method for Islanded AC/DC Hybrid Microgrids

et al. 2022

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Large disturbances frequently happen in isolated AC/DC Hybrid Microgrids. Unfortunately, constant power loads (CPLs) with negative impedance characteristics are equivalent to positive feedback, resulting in an increase in large disturbances. The system can easily become unstable. Consequently, large signal stability criteria are proposed in this paper. Combined with a three-dimensional region of asymptotic stability (3D RAS) method for islanded AC/DC Hybrid Microgrids, important parameters to increase stability margins were determined. Firstly, mixed potential theory was used to derive a large-signal stability criterion. The criteria gave constraints on filtering parameters, CPL power, power of the battery to charge and discharge, AC resistive loads, and DC bus voltage. Then, Lyapunov functions were constructed, and the Lasalle invariance principle was adopted to achieve 3D RAS. When large disturbances emerged, and simultaneously voltage and current varied in 3D RAS, the system always obtained stability and reached new steady-state equilibrium points. Finally, according to comparisons, bigger capacitances of the DC bus capacitor and the AC capacitor, larger battery discharging power and smaller charging power could significantly increase stability margins of islanded Microgrids. Simulations and experimental data have shown that the large signal stability criteria and the 3D RAS work.

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Large-Signal Stability Analysis for Islanded Microgrids Based on Inner Control Loops Approach

Cited by 2 publications

References 7 publications

Steady‐state operating points of islanded virtual synchronous machine microgrid

Steady‐state operating points of islanded virtual synchronous machine microgrid

Large Signal Stability Criteria Combined with a 3D Region of Asymptotic Stability Method for Islanded AC/DC Hybrid Microgrids

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