scholarly journals Operation and Challenges of Multi-Infeed LCC–HVDC System: Commutation Failure, AC/DC Power Flow, and Voltage Stability

2021 ◽  
Vol 11 (18) ◽  
pp. 8637
Author(s):  
Bilawal Rehman ◽  
Atiq ur Rehman ◽  
Waqar Ahmad Khan ◽  
Irfan Sami ◽  
Jong-Suk Ro
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Voltage Stability ◽  
Power Transmission ◽  
Voltage Source ◽  
Future Research ◽  
Long Distance ◽  
Hvdc System ◽  
Dc Power ◽  
Commutation Failure

This paper presents a detailed analysis of commutation failure, AC/DC power flow, and voltage stability of multi-infeed high-voltage direct current (HVDC). The use of HVDC power transmission technology has become common in modern power systems. During the past two decades, HVDC technology has been extensively used for long-distance bulk power transmission to remote areas. Throughout the world, the demand for power has drastically increased in recent years due to industrialization; such situations make HVDC an economic candidate because the distance between power generation plants and load areas is significantly very long. The line-commutated converter (LCC) technology-based HVDC system is well more mature than other available conversion schemes (i.e., voltage source converters), and it is widely used in high-power projects. China had approximately 50 HVDC–LCC links in 2020, and a single LCC-based link with the highest capacity is 12 GW. The installation of several HVDC links in an existing power network has led to a situation where two or more HVDC links terminate in the electric vicinity of each other’s AC network or even in same AC busbar. Such scenarios are termed multi-infeed HVDC system. Multi-infeed HVDC systems bring various challenges related to voltage stability, local and concurrent commutation failure, and AC/DC power flow. Here, the literature available on these phenomena of LCC-based HVDC is discussed for future research. The assumptions and drawbacks of various techniques used for investigating the mentioned phenomena are also highlighted.

scholarly journals A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3222
Author(s):  
Duc Nguyen Huu
Keyword(s):  
Adaptive Control ◽  
Voltage Stability ◽  
Reactive Power ◽  
Control Method ◽  
Offshore Wind ◽  
Voltage Source ◽  
Long Distance ◽  
Control Approach ◽  
Hvdc System ◽  
Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

Voltage Stability Analysis of Wind Power Integrated System Based on Flexible HVDC

2013 ◽  
Vol 336-338 ◽  
pp. 1165-1169
Author(s):  
Ling Long Meng ◽  
Zhen Ning Tang ◽  
Dao Nong Zhang ◽  
Jie Ji ◽  
Jian Hua Zhang
Keyword(s):  
Wind Power ◽  
Voltage Stability ◽  
Transient Stability ◽  
Power Transmission ◽  
Reference Value ◽  
Integrated System ◽  
Voltage Source ◽  
Dc Power ◽  
Ac Power ◽  
Dc Power Transmission

With the scale of integration of wind power increases gradually, the voltage stability and the fluctuation problem of the system caused by integration have become more and more prominent. Traditional AC power transmission mode cannot alleviate the adverse effects of integration of wind power, Flexible DC power transmission has many advantages due to the use of voltage source converters self-commutated characteristics, Flexible DC power provides a new technical method and also provides a solution for the integration. This paper introduces the basic structure and the basic control principle of Flexible DC power transmission technology. Then, through comparing the transient stability level and voltage supporting ability of AC power transmission with that of Flexible DC power transmission, an isolated system is used as an example to elaborate the beneficial contribution that the new integration of wind power make to the voltage stability, which indicates that Flexible DC power transmission technology has broad application prospect in the transmission area of wind power, and gives very good reference value for the Flexible DC power used in integration in the future.

scholarly journals Improved Power Flow Algorithm for VSC-HVDC System Based on High-Order Newton-Type Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yanfang Wei ◽  
Qiang He ◽  
Yonghui Sun ◽  
Yanzhou Sun ◽  
Cong Ji
Keyword(s):  
Power Systems ◽  
Newton Method ◽  
Power Flow ◽  
Automatic Differentiation ◽  
Sixth Order ◽  
Voltage Source ◽  
Third Order ◽  
Type Method ◽  
Hvdc System ◽  
Computation Efficiency

Voltage source converter (VSC) based high-voltage direct-current (HVDC) system is a new transmission technique, which has the most promising applications in the fields of power systems and power electronics. Considering the importance of power flow analysis of the VSC-HVDC system for its utilization and exploitation, the improved power flow algorithms for VSC-HVDC system based on third-order and sixth-order Newton-type method are presented. The steady power model of VSC-HVDC system is introduced firstly. Then the derivation solving formats of multivariable matrix for third-order and sixth-order Newton-type power flow method of VSC-HVDC system are given. The formats have the feature of third-order and sixth-order convergence based on Newton method. Further, based on the automatic differentiation technology and third-order Newton method, a new improved algorithm is given, which will help in improving the program development, computation efficiency, maintainability, and flexibility of the power flow. Simulations of AC/DC power systems in two-terminal, multi-terminal, and multi-infeed DC with VSC-HVDC are carried out for the modified IEEE bus systems, which show the effectiveness and practicality of the presented algorithms for VSC-HVDC system.

scholarly journals A Full-Newton AC-DC Power Flow Methodology for HVDC Multi-Terminal Systems and Generic DC Network Representation

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1658
Author(s):  
Leandro Almeida Vasconcelos ◽  
João Alberto Passos Filho ◽  
André Luis Marques Marcato ◽  
Giovani Santiago Junqueira
Keyword(s):  
Power Systems ◽  
Direct Current ◽  
Power Flow ◽  
Large Scale ◽  
Flow Problem ◽  
Control Strategies ◽  
Problem Formulation ◽  
Expansion Planning ◽  
Dc Power ◽  
Power Flow Problem

The use of Direct Current (DC) transmission links in power systems is increasing continuously. Thus, it is important to develop new techniques to model the inclusion of these devices in network analysis, in order to allow studies of the operation and expansion planning of large-scale electric power systems. In this context, the main objective of this paper is to present a new methodology for a simultaneous AC-DC power flow for a multi-terminal High Voltage Direct Current (HVDC) system with a generic representation of the DC network. The proposed methodology is based on a full Newton formulation for solving the AC-DC power flow problem. Equations representing the converters and steady-state control strategies are included in a power flow problem formulation, resulting in an expanded Jacobian matrix of the Newton method. Some results are presented based on HVDC test systems to confirm the effectiveness of the proposed approach.

scholarly journals Linear power-flow analysis method for AC-DC electric power networks

2021 ◽  
Author(s):  
Mohammadreza Vatani
Keyword(s):  
Power Systems ◽  
Linear Model ◽  
Power Flow ◽  
Linear Models ◽  
Power Converters ◽  
Power Balance ◽  
Balance Equations ◽  
Dc Power ◽  
Phase Angles ◽  
Dc Power Systems

AC-DC power systems have been operating more than sixty years. Nonlinear bus-wise power balance equations provide accurate model of AC-DC power systems. However, optimization tools for planning and operation require linear version, even if approximate, for creating tractable algorithms, considering modern elements such as DERs (distributed energy resources). Hitherto, linear models of only AC power systems are available, which coincidentally are called DC power flow. To address this drawback, linear bus-wise power balance equations are developed for AC-DC power systems and presented. As a first contribution, while AC and DC lines are represented by susceptance and conductance elements, AC-DC power converters are represented by a proposed linear relationship. As a second contribution, a three-step linear AC-DC power flow method is proposed. The first step solves the whole network considering it as a linear AC network, yielding bus phase angles at all busses. The second step computes attributes of the proposed linear model of all AC-DC power converters. The third step solves the linear model of the AC-DC system including converters, yielding bus phase angles at AC busses and voltage magnitudes at DC busses. The benefit of the proposed linear power flow model of AC-DC power system, while an approximation of the nonlinear model, enables representation of bus-wise power balance of AC-DC systems in complex planning and operational optimization formulations and hence holds the promise of phenomenal progress. The proposed linear AC-DC power systems is tested on numerous IEEE test systems and demonstrated to be fast, reliable, and consistent.

scholarly journals Improvement of Power Quality Considering Voltage Stability in Grid Connected System by FACTS Devices

2013 ◽  
pp. 182-187
Author(s):  
Sarika D. Patil
Keyword(s):  
Power Generation ◽  
Wind Power ◽  
Power Flow ◽  
Voltage Stability ◽  
Low Voltage ◽  
Wind Power Generation ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Induction Generators ◽  
Facts Devices

Recently the wind power generation has attracted special interest and many wind power stations are being in service in the world. In the wind turbine that mostly uses induction generators, tend to drain large amounts of Vars from the grid, potentially causing low voltage and may be voltage stability problems for the utility owner, especially in the case of large load variation on distribution feeder. Voltage-source converter based various FACTS devices have been used for flexible power flow control, secure loading and damping of power system oscillations. Some of those are used also to improve transient and dynamic stability of the wind power generation (WPGS).

Multilevel Inverter Based DSTATCOM with Energy Storage Device

2011 ◽  
Vol 55-57 ◽  
pp. 1361-1364
Author(s):  
Jun Li Zhang ◽  
Xiao Feng Lv ◽  
Chao Li
Keyword(s):  
Energy Storage ◽  
Power Flow ◽  
Reactive Power ◽  
Power Transmission ◽  
Electronic Device ◽  
Multilevel Inverter ◽  
Voltage Source ◽  
Storage Device ◽  
Energy Storage Device ◽  
Reactive Power Flow

With the growth of industry manufacturers and population, power quality becomes more and more important issue, and is attracting significant attention due to the increase in the number of sensitive loads. A distribution static compensator (DSTATCOM) is a voltage source inverter (VS1)-based power electronic device, which is usually used to compensate reactive power and sustain the system voltage in distribution power system. Compared with the traditional STATCOM, multilevel STATCOMs exhibit faster dynamic response, smaller volume, lower cost, and higher ratings. A multilevel inverter connected to an energy storage device can control both active and reactive power flow, providing more flexible and versatile power transmission operation. SPWM is actually a kind of multi-pulse trigger mode and used to trigger the switches in DSTATCOM.

An Interline DC Power-Flow Controller (IDCPFC) for Multiterminal HVDC System

2015 ◽  
Vol 30 (4) ◽  
pp. 2027-2036 ◽  
Author(s):  
Wu Chen ◽  
Xu Zhu ◽  
Liangzhong Yao ◽  
Xinbo Ruan ◽  
Zhibing Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Hvdc System ◽  
Dc Power ◽  
Flow Controller ◽  
Power Flow Controller

Decoupled AC/DC Power Flow Strategy for Multiterminal HVDC Systems

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Yixiang Gao ◽  
Shuhui Li ◽  
Weizhen Dong ◽  
Bing Lu
Keyword(s):  
Power Flow ◽  
Control Mode ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Power System Control ◽  
Flow Method ◽  
Hvdc System ◽  
Dc Power ◽  
Bus System ◽  
Power Flow Method

AbstractThis paper proposes a decoupled AC/DC power flow approach for multi-terminal HVDC systems. The proposed method simplifies the power flow computation of multi-terminal HVDC systems while accurately reflecting the operation and control characteristics of VSC (voltage source converter) stations in a HVDC network. In the DC network, the power flow calculation is conducted based on a slack DC bus VSC station and power commends issued to other VSC stations from the power system control center. Then, in the AC power flow calculation, VSC stations are treated as special AC generators that can generate and absorb power from the AC grid in active and reactive power or active power and bus voltage control mode. For validation purpose, the conventional unified power flow method for multi-terminal HVDC systems is built. The paper compares the proposed method with the unified power flow method for an 8-bus multi-terminal HVDC system based on MATPOWER. Then, more case studies for different VSC control modes are conducted and evaluated for the 8-bus system. Afterwards, the proposed method is applied to the power flow study of a more practical and complicated multi-terminal HVDC system based on the IEEE 118-bus system.

scholarly journals Optimal Sizing and Spatial Allocation of Storage Units in a High-Resolution Power System Model

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3365 ◽  
Author(s):  
Lukas Wienholt ◽  
Ulf Müller ◽  
Julian Bartels
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Power Transmission ◽  
Renewable Generation ◽  
Large Power ◽  
Transmission Grid ◽  
Storage Units

The paradigm shift of large power systems to renewable and decentralized generation raises the question of future transmission and flexibility requirements. In this work, the German power system is brought to focus through a power transmission grid model in a high spatial resolution considering the high voltage (110 kV) level. The fundamental questions of location, type, and size of future storage units are addressed through a linear optimal power flow using today’s power grid capacities and a generation portfolio allowing a 66% generation share of renewable energy. The results of the optimization indicate that for reaching a renewable energy generation share of 53% with this set-up, a few central storage units with a relatively low overall additional storage capacity of around 1.6 GW are required. By adding a constraint of achieving a renewable generation share of at least 66%, storage capacities increase to almost eight times the original capacity. A comparison with the German grid development plan, which provided the basis for the power generation data, showed that despite the non-consideration of transmission grid extension, moderate additional storage capacities lead to a feasible power system. However, the achievement of a comparable renewable generation share provokes a significant investment in additional storage capacities.

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