scholarly journals A Novel Two-step Distance Protection for Flexible HVDC Transmission Lines

2021 ◽  
Vol 256 ◽  
pp. 02017
Author(s):  
Zeya Fang ◽  
Minghao Wen ◽  
Junchao Zheng ◽  
Minghao Wen
Keyword(s):  
Transmission Lines ◽  
Low Frequency ◽  
Lumped Parameter Model ◽  
Distance Protection ◽  
Backup Protection ◽  
Hvdc Transmission ◽  
Protection Method ◽  
Dc Line ◽  
Hvdc Line ◽  
Step Distance

DC line fault is one of the key problems that must be solved in a flexible HVDC system. During quite a long time between the existing main protection and backup protection of the HVDC line, there is no line protection method to detect the fault, which may lead the protection at the AC side to act before the backup protection of the DC line. To solve the problem, a novel two-step distance protection for flexible HVDC lines is proposed in this manuscript. Firstly, based on the uniform distributed parameter model, the equivalent lumped parameter model of the HVDC transmission line at low frequency is analyzed. Secondly, according to the time domain differential equation and the least squares algorithm, novel distance protection based on the iterative calculation of fault distance is proposed, which can eliminate the influence of distributed capacitive current and improve the precision of calculation. To improve the rapidity and reliability of the distance protection, low pass filters with two different cut-off frequencies are used to process the electrical quantities. Finally, simulation results show that the proposed distance protection can respond to metallic poleto-ground faults and pole-to-pole faults rapidly and reliably.

A Novel Fault-location Method for HVDC Transmission Lines Based on Concentric Relaxation Principle and Wavelet Packet

2020 ◽  
Vol 13 (5) ◽  
pp. 705-716
Author(s):  
Congshan Li ◽  
Ping He ◽  
Feng Wang ◽  
Cunxiang Yang ◽  
Yukun Tao ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Traveling Wave ◽  
Fault Location ◽  
Wave Attenuation ◽  
Wavelet Packet ◽  
Low Frequency ◽  
Evaluation Process ◽  
Location Method ◽  
Hvdc Transmission ◽  
Instantaneous Energy

Background: A novel fault location method of HVDC transmission line based on a concentric relaxation principle is proposed in this paper. Methods: Due to the different position of fault, the instantaneous energy measured from rectifier and inverter are different, and the ratio k between them is the relationship to the fault location d. Through the analysis of amplitude-frequency characteristics, we found that the wave attenuation characteristic of low frequency in the traveling wave is stable, and the amplitude of energy is larger, so we get the instantaneous energy ratio by using the low-frequency data. By using the method of wavelet packet decomposition, the voltage traveling wave signal was decomposed. Results: Finally, calculate the value k. By using the data fitting, the relative function of k and d can be got, that is the fault location function. Conclusion: After an exhaustive evaluation process considering different fault locations, fault resistances, and noise on the unipolar DC transmission system, four-machine two-area AC/DC parallel system, and an actual complex grid, the method presented here showed a very accurate and robust behavior.

scholarly journals Novel protection method for VSC-HVDC transmission lines

2019 ◽  
Vol 2019 (16) ◽  
pp. 2142-2146
Author(s):  
Lingtong Jiang ◽  
Qing Chen ◽  
Lei Wang ◽  
Pu Zhao ◽  
Yu Zeng ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Hvdc Transmission ◽  
Protection Method ◽  
Hvdc Transmission Lines

scholarly journals A Study for the Measurement of the Minimum Clearance Distance between the 500 kV DC Transmission Line and Vegetation

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2606
Author(s):  
Kumail Kharal ◽  
Chang-Hwan Kim ◽  
Chulwon Park ◽  
Jae-Hyun Lee ◽  
Chang-Gi Park ◽  
...  
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Electrical Power ◽  
Long Distance ◽  
Dc Voltage ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Dc Line ◽  
Pass Through

High voltage direct current (HVDC) transmission is being widely implemented for long-distance electrical power transmission due to its specific benefits over high voltage alternating current (HVAC) transmission. Most transmission lines pass through forests. Around the HVDC lines, an arc to a nearby tree may be produced. Thus, there should be a minimum possible clearance distance between a live conductor and a nearby tree, named the minimum vegetation clearance distance (MVCD), to avoid short-circuiting. Measurement of minimum clearance distance between the conductor and trees is a significant challenge for a transmission system. In the case of HVAC transmission, a large amount of research has been undertaken in the form of the Gallet equation for the measurement of this distance, whereas for HVDC transmission no substantial work has been done. An equivalent AC voltage value can be derived from the DC voltage value in order to use the Gallet equation. This paper presents an experimental measurement technique for determining the MVCD at 500 kV to verify the results obtained from the Gallet equation in the case of DC voltage. Performing the experiment with a 500 kV DC line is not possible in the laboratory due to safety concerns. Therefore, an experiment up to 60 kV is conducted to measure the MVCD for DC voltage. The measured results achieved from the experiment are then extrapolated to calculate the MVCD at 500 kV.

Distance Protection for HVDC Transmission Lines Considering Frequency-Dependent Parameters

2013 ◽  
Vol 28 (2) ◽  
pp. 723-732 ◽  
Author(s):  
Jiale Suonan ◽  
Jiankang Zhang ◽  
Zaibin Jiao ◽  
Liming Yang ◽  
Guobing Song
Keyword(s):  
Transmission Lines ◽  
Distance Protection ◽  
Frequency Dependent ◽  
Hvdc Transmission ◽  
Hvdc Transmission Lines

scholarly journals VSC-HVDC Bipolar Grid Based On Novel Distance Protection Scheme

2019 ◽  
Vol 8 (4) ◽  
pp. 2524-2529
Keyword(s):  
Practical Implementation ◽  
Zone Boundary ◽  
Distance Protection ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
Protection Scheme ◽  
End Point ◽  
Internal Fault ◽  
Protection Method ◽  
Lumped Parameter

Mostly distance protection is widely used in HVAC system no practical implementation is done for HVDC system. It is essential to measure accurately difference in internal fault from external correctly in distance protection at the zone boundary. The smoothing reactor in HVDC system is present at two ends and it can be considered as the operating boundary of distance protection. Considering these feature this paper introduce distance protection method for HVDC transmission line. Current and voltage at end-point are planned accurately using those at the relay point, based on distributed parameter model. The line between the fault point and end point is simplified as RL model lumped parameter and differential equations obtain fault distance. In this way, accuracy of calculation at the zone boundary is attained, that contributes to the improvement in operation of protection. Simulation results show that proposed method is used as primary protection for HVDC transmission and is capable of protecting the whole line with high rapidity.

scholarly journals Distance backup protection using supply currents on a line with several branches

Vestnik IGEU ◽  
2019 ◽  
pp. 49-59
Author(s):  
L.M. Kolesov ◽  
V.V. Mozhzhukhina
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Impedance Measurement ◽  
Total Power ◽  
Distance Protection ◽  
Backup Protection ◽  
Response Characteristics ◽  
Mode Recognition ◽  
Urgent Task ◽  
Short Circuits

The third step of distance protection is used as backup protection against phase-to-phase short circuits on 110–220 kV transmission lines. The main problem when using these protections on a line with several branches is to ensure the effectiveness of distant backup protection in case of phase-to-phase short circuits behind branch transformers of substations. The effective solution to distant backup protection is possible to provide by expanding the information base of protection. Currently, backup protection of lines with branches is being developed with control of currents and their components when using a communication channel, and based on algorithmic models of the facility. In this regard, the urgent task is to develop an algorithm for the distance protection ensuring the required sensibility during short circuits on the lower voltage side of the branch transformers. Analytical methods of determining the impedance measurement and simulation in Simulink and SimPowerSystems of the Matlab modeling system are used. The effectiveness of distant backup protection can be evaluated on the basis of recognition possibility of short circuit modes behind the branch transformers. Analytical expressions have been obtained to determine the impedance measurement during phase-to-phase short-circuits behind a branch transformer and under load conditions. Criteria have been developed to assess the proposed protection possibility to recognize the mode of phase-to-phase short circuits behind the branch transformer. Studies have shown that the main factor determining the possibility of mode recognition is the ratio between the protected transformer power and the total power of the branches loads. The use of several impedance measuring elements with their own response characteristics for branches with transformers of different capacities provides mode recognition for any possible correlation of power of branch substations. The use of the distance protection implementation option developed by the authors allows providing the required sensitivity for short circuits behind branch transformers and to solve the problem of distance backup line protection on a line with several branches. The reliability of the data obtained is confirmed by the correspondence of analytical research and simulation results.

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