scholarly journals Integration of Voltage Source Converters in Steady-State RMS Short-Circuit Analysis

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3610
Author(s):  
Carlos Coelho Teixeira ◽  
Helder Leite
Keyword(s):  
Steady State ◽  
Reactive Power ◽  
Early Stage ◽  
Short Circuit ◽  
Current Source ◽  
Circuit Analysis ◽  
Voltage Source ◽  
Voltage Source Converters ◽  
Analysis Techniques ◽  
Short Circuit Analysis

Voltage source converters (VSCs) are self-commutated converters able to generate AC voltages with or without the support of an AC connecting grid. VSCs allow fast control of active and reactive powers in an independent way. VSCs also have black start capability. Their use in high-voltage direct current (HVDC) systems, comparative to the more mature current source converter (CSC)-based HVDC, offers faster active power flow control. In addition, VSCs provide flexible reactive power control, independent at each converter terminal. It is also useful when connecting DC sources to weak AC grids. Steady-state RMS analysis techniques are commonly used for early-stage analysis, for design purposes and for relaying. Sources interfaced through DC/AC or AC/DC/AC converters, opposite to conventional generators, are not well represented by electromotive forces (E) behind impedance models. A methodology to include voltage source converters (VSCs) in conventional RMS short-circuit analysis techniques is advanced in this work. It represents an iterative procedure inside general calculation techniques and can even be used by those with only basic power electronics knowledge. Results are compared to those of the commercial software package PSS®CAPE to demonstrate the validity of the proposed rmsVSC algorithm.

scholarly journals Contribution of Voltage Support Function to Virtual Inertia Control Performance of Inverter-Based Resource in Frequency Stability

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4220
Author(s):  
Dai Orihara ◽  
Hiroshi Kikusato ◽  
Jun Hashimoto ◽  
Kenji Otani ◽  
Takahiro Takamatsu ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Function ◽  
Current Source ◽  
Voltage Control ◽  
Frequency Stability ◽  
Voltage Regulation ◽  
System Stability ◽  
Voltage Source ◽  
Apparent Difference ◽  
Virtual Inertia

Inertia reduction due to inverter-based resource (IBR) penetration deteriorates power system stability, which can be addressed using virtual inertia (VI) control. There are two types of implementation methods for VI control: grid-following (GFL) and grid-forming (GFM). There is an apparent difference among them for the voltage regulation capability, because the GFM controls IBR to act as a voltage source and GFL controls it to act as a current source. The difference affects the performance of the VI control function, because stable voltage conditions help the inertial response to contribute to system stability. However, GFL can provide the voltage control function with reactive power controllability, and it can be activated simultaneously with the VI control function. This study analyzes the performance of GFL-type VI control with a voltage control function for frequency stability improvement. The results show that the voltage control function decreases the voltage variation caused by the fault, improving the responsivity of the VI function. In addition, it is found that the voltage control is effective in suppressing the power swing among synchronous generators. The clarification of the contribution of the voltage control function to the performance of the VI control is novelty of this paper.

Teaching Short - Circuit Calculation with Off - Nominal Turns Ratio Transformers

TEM Journal ◽  
2021 ◽  
pp. 1525-1533
Author(s):  
Allen A. Castillo ◽  
M. Natalia Galván Osuna ◽  
Norma A. Barboza Tello ◽  
Alejandra J. Vega
Keyword(s):  
Case Studies ◽  
Short Circuit ◽  
Circuit Analysis ◽  
Industrial System ◽  
Software Simulation ◽  
Three Phase ◽  
Short Circuit Calculation ◽  
The Subject ◽  
Ieee Standards ◽  
Short Circuit Analysis

Teaching short-circuit analysis is conducted primarily through case studies; however, there are not many validated short-circuit studies available on the subject, especially when considering off-nominal turns ratio transformers. In order to improve the teaching of short-circuit analysis, a three phase short-circuit study in an industrial system according to ANSI/IEEE standards by means of Zmatrix method is presented; two case studies are considered: the industrial system with nominal and offnominal turns ratio transformers, in both cases the step by step solution is given in an explicit manner and the analytical results are validated through software simulation.

scholarly journals Research on Serial VSC-LCC Hybrid HVdc Control Strategy and Filter Design Scheme

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2260
Author(s):  
Fan Cheng ◽  
Lijun Xie ◽  
Zhibing Wang
Keyword(s):  
Reactive Power ◽  
Filter Design ◽  
Control Strategies ◽  
Short Circuit ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Level Control ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Design Scheme

This paper investigated the characteristics of a novel type of hybrid high voltage direct current (HVdc) converter, which is composed by line commutated converter series with voltage source converter. The system and valve level control strategies are introduced, which can provide ac system voltage support. A novel filter design scheme composed by resonant filers for hybrid HVdc are also proposed, which can decrease the capacity of reactive power compensation equipment without deteriorate harmonic characteristics. The ac voltage of HVdc fluctuation level caused by transmitted power variation will be effectively reduced, with the coordination between filter design scheme and converter control. In addition, the influence of ac grid strength is also analyzed by equivalent source internal impedance represented by short circuit ratio (SCR). Finally, the +800 kV/1600 MW hybrid HVdc system connecting two ac grids under different SCR cases are studied, and the PSCAD/EMTDC simulation results have validated the effectiveness for proposed strategy.

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