A Fast Full-Line Tripping Distance Protection Method for HVDC Transmission Line

The Gas-insulated Line (GIL) is a technical equipment that allows power transmission underground at high voltage level. The UHV GIL-overhead hybrid transmission line is an essential way for power transmission in complicated landscapes. Because of the distributed capacitance of the UHV transmission line and the difference of the structure and the electrical parameters between GIL and overhead transmission line, the distance protection based on uniform lumped parameters cannot be applied to this hybrid transmission line directly. In order to overcome the shortcomings, this paper studies and proposes a new principle of distance protection for the UHV GIL-overhead hybrid transmission line based on frequency domain lossless transmission line equation, with the distributed capacitance accounted. Then, the paper presents a setting scheme for this distance protection with the hybrid line parameters considered. Finally, tests are carried out on the Power Systems Computer Aided Design (PSCAD) platform, and the accuracy and reliability of the distance protection method proposed are verified by simulation results.

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

E3S Web of Conferences ◽

10.1051/e3sconf/202125602017 ◽

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.

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VSC-HVDC Bipolar Grid Based On Novel Distance Protection Scheme

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d7257.118419 ◽

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.

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