scholarly journals Non-characteristic Harmonic Analysis of Uhv ac/dc Systems

2019 ◽  
Vol 260 ◽  
pp. 02011
Author(s):  
Jie Gong ◽  
Lixing Zhou ◽  
Lawu Zhou ◽  
Mengdi Zhou
Keyword(s):  
Direct Current ◽  
Power Transmission ◽  
Transmission System ◽  
Operating Conditions ◽  
Operation Condition ◽  
Long Distance ◽  
Current Transmission ◽  
Pulse Converter ◽  
Actual Operation ◽  
Grid Side

Uhv direct current transmission has developed rapidly in China due to its unique advantages of large capacity, long distance and high voltage. A series of researches have been carried out on the non-characteristic harmonic current in the grid side of uhv dc transmission system. This paper is aimed at the analysis of non-characteristic harmonics in the uhv direct current transmission system using a 12-pulse converter. Under ideal operating conditions, the system has characteristic non-characteristic harmonics. However, the actual operation condition of HVDC project is not ideal, so there are non-characteristic harmonics. The Simulink of MATLAB is used to model a uhv dc power transmission system. Based on this model, dynamic simulation is carried out to analyze the steady-state and dynamic characteristics of the system. Meanwhile, several common faults in the system are simulated. The simulation result is the same as the actual phenomenon, which provides support for identification, control and fault diagnosis of uhv ac/dc transmission system in the future.

Research of UHV DC Transmission Based on the Current Control

2011 ◽  
Vol 143-144 ◽  
pp. 19-23
Author(s):  
Hai Long Zhao ◽  
Zhong Ying Lin
Keyword(s):  
Transmission System ◽  
Current Control ◽  
Good Effect ◽  
Submarine Cable ◽  
Long Distance ◽  
Harmonic Control ◽  
Dc Power ◽  
Current Transmission ◽  
Simulation Results ◽  
Time Type

Compared with AC (alternating current) transmission, DC(direct current) transmission has obvious superiority at high power, long distance, submarine cable transmission and asynchronous interconnected between exchange systems etc.. This paper constructed a kind of 12 pulse bridge UHV DC transmission system that includes control protection function through MATLAB/Simulink tool. By setting the breaker parameters, this paper studied the 12 pulse bridge UHV DC transmission system AC/DC side in case of setting down time, type and cleared. The simulation results demonstrate that this system has a good effect in harmonic control and it has no power compensations in realizing HV DC process, and it can completely work as an important reference in constructing HV DC power grid.

Numerical Simulation of IAQ under Up-Suction Exhaust Hood in Commercial Kitchen

2011 ◽  
Vol 250-253 ◽  
pp. 3228-3231 ◽  
Author(s):  
Da Hua Jiang ◽  
An Gui Li ◽  
Fa En Shi ◽  
Zhi Hua Wang
Keyword(s):  
Exhaust System ◽  
Operating Conditions ◽  
Airflow Rate ◽  
Exhaust Hood ◽  
Operation Condition ◽  
Main Site ◽  
Actual Operation ◽  
The Common ◽  
Simulation Results ◽  
Save Energy

For particular commercial kitchen, using CFD software to build model according to the actual operation condition uttermost, adopting the exhaust system of up-suction hood, the effect of exhaust airflow rate on working temperature,velocity,CO2 concentration at main site in commercial kitchen is studied. According to the common four calculation methods of airflow rate of exhaust hood, the simulation results shows 4.81 m3/s of exhaust system can realize eliminating harmful gas quickly and effectively, IAQ is good relatively. Based on of it, additional airflow rate can not improve emissions effect and operating conditions obviously, whereas it can be detrimental to save energy. The simulation results help design exhaust system.

Dynamic simulator for multi-terminal direct current transmission system

2016 ◽  
Author(s):  
Zhijie Liu ◽  
Ke-Jun Li ◽  
Xinhan Meng ◽  
Wei-Jen Lee ◽  
Zhuo-di Wang ◽  
...  
Keyword(s):  
Direct Current ◽  
Transmission System ◽  
Current Transmission ◽  
Dynamic Simulator

Reliability Evaluation & Analysis of UHVDC Transmission System

2013 ◽  
Vol 860-863 ◽  
pp. 2107-2111
Author(s):  
Cong Zhao ◽  
Yuan Zeng ◽  
Guang Yu Lei
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Fault Tree Analysis ◽  
Transmission System ◽  
Repair Time ◽  
Analysis Method ◽  
Fault Probability ◽  
Tree Analysis ◽  
High Voltage Direct Current ◽  
Current Transmission

The reliability of UHVDC (ultra-high voltage direct current) transmission system is significant to the development of power grid. The paper selects dual 12-pulse converters on each pole to model and analyze the UHVDC transmission system. Firstly, the system is divided into six subsystems to evaluate the reliability by the fault tree analysis method. Then based on the fault frequency and the repair time of each subsystems bottom components, the paper calculates the fault frequency and the repair time of each subsystem. Using the frequency and duration method, the paper calculates the fault probability, fault frequency and repair time of the whole system. Finally, it is validated by the actual data of typical lines.

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