scholarly journals Improving Transient Stability of the Nigerian 330kv Transmission System on Ajaokuta - Benin Transmission Line with the help of artificial Neural Network (ANN) based VSC high Voltage direct current method

Author(s):  
C. C Okolo ◽  
O. A Ezechukwu ◽  
F. O Enemuo ◽  
A. E Anazia ◽  
J. O Onuegbu
Author(s):  
Ryota Kinjo ◽  
Hidehito Matayoshi ◽  
Gul Ahmad Ludin ◽  
Abdul Motin Howlader ◽  
Naomitsu Urasaki ◽  
...  

AbstractIn consideration of the natural environment and depletion of energy resources, the widespread use of electric power system is expected in which the power is generated from sources of renewables such as wind and solar. When these plants are introduced in large scale, the use of broad land is required. Due to low transmission losses and small stability problems, multi-terminal high voltage direct current (MTDC) transmission becomes advantageous as long-distance power transmission system. Since DC current does not incorporate a zero cross point, therefore it’s blocking is difficult. This paper proposes a DC resonant semiconductor breaker which enables rapid fault clearance for self-excited HVDC transmission. This circuit breaker is connected as a semiconductor switch, in parallel with a group of capacitors, and resistors in the DC transmission line. The capacitor is charged to a higher voltage from the DC transmission line. For generating reverse current to allow the zero cross point in the transmission line, the semiconductor switch turns on to open the circuit breaker. After blocking, the inductance of the line is demagnetized by the resistor and fault clearing is achieved. The system except fault point can continue its normal operation.


2010 ◽  
Vol 171-172 ◽  
pp. 171-174
Author(s):  
Hong Cheng ◽  
Peng Kun Liu ◽  
Yu Ling Wang ◽  
Chang Xin Nai

The dipole spacing can directly affects the detecting sensitivity and accuracy in the landfill leakage detection by the high voltage direct current method. Based on the high voltage DC detecting model, the impact of dipole spacing on locating leaks is analyzed taking a single leak and multiple leaks as example. The results show that the greater the dipole spacing is, the higher the detecting sensitivity is; the smaller the dipole spacing is, the higher the detecting accuracy is. For multiple leaks, only one leak can be located when the dipole spacing is greater than the distance between the two leaks. In order to detect all leaks correctly, the dipole spacing should be smaller than the distance between the two leaks.


2015 ◽  
Vol 740 ◽  
pp. 466-469
Author(s):  
Xue Hua Jiang

High Voltage Direct Current (HVDC) system was often the link between major power grids. In order to ensure the safe operation of HVDC, fault diagnosis method was studied. The system structure of HVDC Light system was analyzed, and the normal and fault conditions of the transmission system were simulated in the Matlab platform. This method was very convenient and simple, and it could restore the real situation. The use of simulated waveform could effectively identify the fault types of actual situation, and then it was a flexible, efficient and practical method of fault diagnosis in HVDC Light system.


2013 ◽  
Vol 860-863 ◽  
pp. 2107-2111
Author(s):  
Cong Zhao ◽  
Yuan Zeng ◽  
Guang Yu Lei

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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