The Influence Analysis of Rectifier Side Control Mode on Commutation Failure in UHVDC

2014 ◽  
Vol 631-632 ◽  
pp. 339-344
Author(s):  
Jun Xiang Rong ◽  
Ju Rui Yang
Keyword(s):  
Power Control ◽  
Short Circuit ◽  
Transmission System ◽  
Current Control ◽  
Control Mode ◽  
Constant Current ◽  
Critical Voltage ◽  
Constant Power ◽  
Ground Fault ◽  
Commutation Failure

This paper studies the influence of different control modes in the rectifier side (constant current control, constant power control) on commutation failure in UHVDC transmission system. The study is based on Yunnan-Guangdong ±800kV UHVDC transmission system and simulated in PSCAD/EMTDC. A wealth of simulation results indicate that the control ability of the constant current control on commutation failure caused by the critical voltage ratio of inverter transformer increased is worse than the constant power control; the control ability of the constant current control on commutation failure caused by three-phase grounding fault happens at inverter side AC bus is worse than the constant power control; The control ability of the constant current control on commutation failure caused by phase to phase short circuit fault or single-phase ground fault happens at inverter side AC bus is worse than the constant power control.

Reactive Power Compensation Method of HVDC Commutation Failure

2014 ◽  
Vol 536-537 ◽  
pp. 1510-1513
Author(s):  
Xiao Ming Wang ◽  
Qi Zhang ◽  
Bin Qian
Keyword(s):  
Reactive Power ◽  
Voltage Drop ◽  
Critical Value ◽  
Reactive Power Compensation ◽  
Transmission System ◽  
Critical Voltage ◽  
High Voltage Direct Current ◽  
Commutation Failure ◽  
The Difference ◽  
Bus Voltage

In the high-voltage direct current transmission system, the difference value between the landing phase voltage and DC transmission system commutation failure of the critical voltage drop value, as system occurred in the critical value of commutation failure. When commutation voltage lower than the critical value would reduce arc Angle, caused by commutation failure。Therefore, by using the method of reactive power compensation to keep converter bus voltage stability, can avoid commutation failure.

scholarly journals Demonstration of Converter Control Interactions in MMC-HVDC Systems

Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 175
Author(s):  
Jinlei Chen ◽  
Sheng Wang ◽  
Carlos E. Ugalde-Loo ◽  
Wenlong Ming ◽  
Oluwole D. Adeuyi ◽  
...  
Keyword(s):  
Power Control ◽  
Current Control ◽  
Operating Conditions ◽  
The Other ◽  
Constant Current ◽  
Droop Control ◽  
Dc Voltage ◽  
Control Scheme ◽  
Point To Point ◽  
Dc Current

Although the control of modular multi-level converters (MMCs) in high-voltage direct-current (HVDC) networks has become a mature subject these days, the potential for adverse interactions between different converter controls remains an under-researched challenge attracting the attention from both academia and industry. Even for point-to-point HVDC links (i.e., simple HVDC systems), converter control interactions may result in the shifting of system operating voltages, increased power losses, and unintended power imbalances at converter stations. To bridge this research gap, the risk of multiple cross-over of control characteristics of MMCs is assessed in this paper through mathematical analysis, computational simulation, and experimental validation. Specifically, the following point-to-point HVDC link configurations are examined: (1) one MMC station equipped with a current versus voltage droop control and the other station equipped with a constant power control; and (2) one MMC station equipped with a power versus voltage droop control and the other station equipped with a constant current control. Design guidelines for droop coefficients are provided to prevent adverse control interactions. A 60-kW MMC test-rig is used to experimentally verify the impact of multiple crossing of control characteristics of the DC system configurations, with results verified through software simulation in MATLAB/Simulink using an open access toolbox. Results show that in operating conditions of 650 V and 50 A (DC voltage and DC current), drifts of 7.7% in the DC voltage and of 10% in the DC current occur due to adverse control interactions under the current versus voltage droop and power control scheme. Similarly, drifts of 7.7% both in the DC voltage and power occur under the power versus voltage droop and current control scheme.

Operation of Multi DC Smart Grids Based on Renewable Energy Sources and Protection of DC Transmission Line

2012 ◽  
Vol 13 (3) ◽  
Author(s):  
Thabit S. Nassor ◽  
Masahiko Kina ◽  
Tomonobu Senjyu ◽  
Atsushi Yona ◽  
Toshihisa Funabashi
Keyword(s):  
Power Control ◽  
Transmission Line ◽  
Smart Grids ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Ground Fault ◽  
Bus Voltage ◽  
Grid Side ◽  
Photovoltaic Generators ◽  
Consumption Control

Abstract This paper presents the operation under fault and protection of multi DC smart grids connected to the DC transmission line. The smart grid consists of wind turbine and photovoltaic generators, controllable loads, generator side and grid side inverters. The voltage stability of the DC bus voltage is attained by applying the power consumption control of controllable loads, the power control of grid connected converter and power control of renewable plants. On the other hand, the fault protection for short-circuit and low resistance ground fault at the DC transmission line was sighted. Simulation results based on PSIM are provided to demonstrate the effectiveness of the system.

Modeling and Analysis of Arc Weld Inverter Based on Double Closed-Loop Control

2010 ◽  
Vol 36 ◽  
pp. 109-114
Author(s):  
Kuan Fang He ◽  
Ji Gang Wu ◽  
Xue Jun Li
Keyword(s):  
Power Supply ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Mathematic Model ◽  
Current Control ◽  
Soft Switching ◽  
Control Mode ◽  
Constant Current ◽  
Optimized Design ◽  
Loop Control

According to the soft-switching pulsed SAW (Submerged arc weld) weld power supply based on the double closed-loop constant current control mode, a small signal mathematic model of main circuit of soft-switching SAW inverter was established by applying the method of three-terminal switching device modeling method, and the mathematic model of double closed-loop phase-shift control system circuit was established by applying the method of state-space averaging method. Dynamic performance of the inverter was analyzed on base of the established mathematic model, and the tested wave of dynamic performance was shown by experimentation. Research and experimentation show that relation between structure of the power source circuit and dynamic performance of the controlling system can be announced by the established mathematic model, which provides development of power supply and optimized design of controlling parameter with theoretical guidance.

scholarly journals An Enhanced Control Strategy for the Stable Operation of Distributed Generation during Grid-Connected and Islanded Mode

2018 ◽  
Vol 7 (2) ◽  
pp. 147
Author(s):  
Suman Khichar ◽  
Yatindra Gopal ◽  
Mahendra Lalwani
Keyword(s):  
Power Flow ◽  
Current Control ◽  
Detection Technique ◽  
Control Mode ◽  
Constant Current ◽  
Stable Operation ◽  
Point Tracking ◽  
Loop Detection ◽  
Nondetection Zone ◽  
Voltage Control Mode

The incident of islanding occurs while the distributed generator fed constant power into the grid after power flow on the source of essential utility has been intermittent. If islanding is not rapidly detected, it can reason serious security and harmful condition.  This paper presents coordinated manage of solar photovoltaic unit through maximum power point tracking technique to make available voltage and frequency support for an islanding condition. In normal condition, structure works as constant current control mode subsequent to islanding the structure switched to voltage control mode. The projected technique is capable to discriminate involving an islanding and a non-islanding occurrence. In this paper phase locked loop detection technique designed for detecting islanding situation is conceded out. The authentication of proposed system is established efficiently using MATLAB/ Simulink environment. The simulated results exhibit that the islanding detection technique has zero nondetection zone property and be able to detect islanding within few seconds

scholarly journals ANALYSIS OF INVERTER FED MICROGRIDS FOR DIFFERENT MODES OF OPERATION IN MATLAB/SIMULINK

2013 ◽  
pp. 187-190
Author(s):  
SREELEKSHMI R S ◽  
SUNITHA R
Keyword(s):  
Control Strategies ◽  
Voltage Control ◽  
Current Control ◽  
Control Mode ◽  
Constant Current ◽  
Control Loops ◽  
Control Techniques ◽  
Mode Of Operation ◽  
Islanded Mode ◽  
Voltage Control Mode

This paper presents analysis of control techniques of a converter fed microgrid in grid connected mode and islanded mode of operation. Here two control strategies are discussed , one for grid connected mode and the other for islanded mode of operation. In grid connected mode of operation the DG inverter system works in constant current control mode, and provide preset power to the grid, while in islanded mode of operation the DG inverter system goes to voltage control mode. Voltage control mode is simple and has a low number of control loops.

scholarly journals Design of Controller for Transition of Grid Connected Microgrid to Island Mode

2021 ◽  
Vol 12 (2) ◽  
pp. 845-854
Author(s):  
K.Rayudua, Et. al.
Keyword(s):  
Pi Controller ◽  
Current Control ◽  
Wind Power Generation ◽  
Control Mode ◽  
Normal Operation ◽  
Constant Current ◽  
Pv System ◽  
Hybrid Microgrid ◽  
Distributed Generators ◽  
Voltage Control Mode

A microgrid is the combination of Distributed generators that interconnected with the main grid to ensure continuity in supply to the load. The operating system will be in grid-connected and the island mode. This paper presents a mathematical model of hybrid microgrid consisting of PV system, wind power generation using DFIG which are integrated to the utility grid and a PI Controller for controlling the transition from grid-connected mode to island mode and normal operation, each DG inverter sated in constant current control mode to provide preset power to the main grid. When it disconnects from the main grid each DG inverter detects and connect to voltage control mode in the islanding situation. The modeling is performed in MATLAB Simulink and results are discussed out to verify the operation of the proposed system  

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