scholarly journals Small-Signal Stability Analysis of Multi-Terminal DC Grids

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 130
Author(s):  
Amr Radwan
Keyword(s):  
Steady State ◽  
State Space ◽  
State Space Model ◽  
Operation Time ◽  
Power Sharing ◽  
Voltage Source ◽  
Small Signal ◽  
Small Signal Stability ◽  
Steady State Operation ◽  
The Individual

This paper presents a detailed small-signal analysis and an improved dc power sharing scheme for a six terminal dc grid. The multi-terminal DC (MTDC) system is composed of (1) two voltage-source converters (VSCs) entities operating as rectification stations; (2) two VSCs operating as inverting stations; (3) two dc/dc conversion stations; and (4) an interconnected dc networking infrastructure. The small-signal state-space sub-models of the individual entities are developed and integrated to formulate the state-space model of the entire system. Using the modal analysis, it is shown that the most critical modes are associated with the power sharing droop coefficients of the rectification stations, which are constrained by the steady-state operational requirements. Therefore, a second degree-of-freedom compensation scheme is proposed to improve the dynamic response of the MTDC system without influencing the steady-state operation. Time domain simulation results are presented to validate the analysis and show the effectiveness of the proposed techniques.

scholarly journals A Building Block Method for Modeling and Small-Signal Stability Analysis of the Autonomous Microgrid Operation

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1492 ◽  
Author(s):  
Bojan Banković ◽  
Filip Filipović ◽  
Nebojša Mitrović ◽  
Milutin Petronijević ◽  
Vojkan Kostić
Keyword(s):  
State Space ◽  
Building Block ◽  
System Analysis ◽  
State Space Model ◽  
Model Complexity ◽  
Individual Element ◽  
Small Signal Stability ◽  
Block Method ◽  
Parameter Modification ◽  
The Individual

The task of the whole microgrid state-space matrix creation is usually done in a preferred textual programming language, and it presents a complicated, time-consuming, and error-prone job for a researcher without good coding practices. To ease the modeling task, contribute to the adaptation of new microgrid structures, control algorithms, and devices, and to improve the flexibility of the model, a graphical element building block method is proposed in this paper. With the proposed approach model creation of the whole microgrid is reduced to the creation of the individual element state-space model that is linked with other elements in a logical way with a graphical connection. Elements are then grouped into meaningful wholes and encapsulated with the appropriate graphical user interface that enables easy parameter modification and model complexity change. More detailed DC/DC and DC/AC models of converters than those in the literature concerning microgrid stability are presented in this paper. Those converters are incorporated in a microgrid, whose model is created using the proposed approach in MATLAB/Simulink. The dynamic response examination of the model remains easy, just as with all Simulink models, while for the linear system analysis, a specialized toolbox is used.

scholarly journals Multi-machine power system state-space modelling for small-signal stability assessments

2013 ◽  
Vol 37 (24) ◽  
pp. 10141-10161 ◽  
Author(s):  
Carlos E. Ugalde-Loo ◽  
Enrique Acha ◽  
Eduardo Licéaga-Castro
Keyword(s):  
Power System ◽  
State Space ◽  
Small Signal ◽  
System State ◽  
Small Signal Stability ◽  
Signal Stability

scholarly journals Stability of Power Grids: State-of-the-art and Future Trends

2019 ◽  
Vol 217 ◽  
pp. 01017
Author(s):  
Nikita Tomin ◽  
Daniil Panasetsky ◽  
Alexey Iskakov
Keyword(s):  
Steady State ◽  
Lyapunov Function ◽  
Power Systems ◽  
Transient Stability ◽  
State Of The Art ◽  
Test System ◽  
Power Grids ◽  
Small Signal ◽  
Small Signal Stability ◽  
Signal Stability

The state of the art of transient stability and steady-state (small signal) stability in power grids are reviewed. Transient stability concepts are illustrated with simple examples; in particular, we consider two machine learning-based methods for computing region of attraction: ROA produced by Neural Network Lyapunov Function; estimation of the ROA of IEEE 39-bus system using Gaussian process and Converse Lyapunov function. We discuss steady state stability in power systems, and using Prony’s modal analysis for evaluating small signal stability for the 7 Bus Test system and real French power system.

scholarly journals Modeling and Analyzing the Effect of Frequency Variation on Weak Grid-Connected VSC System Stability in DC Voltage Control Timescale

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4458 ◽  
Author(s):  
Yang ◽  
Yuan
Keyword(s):  
Voltage Control ◽  
System Stability ◽  
Voltage Source ◽  
Frequency Variation ◽  
Voltage Source Converter ◽  
Small Signal ◽  
Small Signal Stability ◽  
Dc Voltage ◽  
Weak Grid ◽  
Dc Voltage Control

The effect of frequency variation on system stability becomes crucial when a voltage source converter (VSC) is connected to a weak grid. However, previous studies lack enough mechanism cognitions of this effect, especially on the stability issues in DC voltage control (DVC) timescale (around 100 ms). Hence, this paper presented a thorough analysis of the effect mechanism of frequency variation on the weak grid-connected VSC system stability in a DVC timescale. Firstly, based on instantaneous power theory, a novel method in which the active/reactive powers are calculated with the time-varying frequency of voltage vectors was proposed. This method could intuitively reflect the effect of frequency variation on the active/reactive powers and could also help reduce the system order to a certain extent. Then, a small-signal model was established based on the motion equation concept, to depict the effect of frequency variation on the weak grid-connected VSC system dynamics. Furthermore, an analytical method was utilized to quantify the effect of frequency variation on the system’s small-signal stability. The quantitative analysis considered the interactions between the DC voltage control, the terminal voltage control, phase-locked loop, and the power network. Finally, case studies were conducted, and simulation results supported the analytical analyses.

scholarly journals Small-signal stability modeling of the microgrid with network transients taken into consideration

2021 ◽  
pp. 17-23
Author(s):  
Hung Nguyen-Van, Huy Nguyen-Duc Nguyen
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
State Space Model ◽  
Voltage Regulation ◽  
Electrical Network ◽  
Small Signal ◽  
Small Signal Stability ◽  
Synchronous Generators ◽  
Electrical Loads ◽  
The Stability

The development of a small signal model that accurately reflects dynamic processes plays an essential role in the stability analysis and control of power systems. The main components in a microgrid power system are synchronous generators, the electrical network, electrical loads, and inverters. A method to derive the microgrid state-space model is proposed in the article. This method is based on linearized models of synchronous generators, electronic power inverters, networks, and loads. This model can be further developed to account for microgrid control schemes such as frequency control and voltage regulation. A small-signal analysis of the Microgrid model is also carried out in this work.

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