Extra-high voltage long-distance DC line protection algorithm based on new energy grid connection

Abstract

The invention discloses an extra-high voltage long-distance DC line protection algorithm based on new energy grid connection. The algorithm mainly comprises the following steps: obtaining electrical sampling data obtained after sampling of each electrode of the two sides of a protected DC transmission line, and carrying out initial judgment on practical operation state of the line in real time; according to the state obtained after initial judgment, starting an integral-form longitudinal impedance time domain protection algorithm; and when the DC transmission line drives time domain increment of the corresponding detected current above to be able to be measured effectively due to fault, starting a set longitudinal impedance algorithm and determining whether the line has an internal fault according to the time domain integral result of longitudinal impedance. Through a novel extra / ultrahigh-voltage DC transmission line unit protection algorithm, high-frequency harmonic interference hard to be resisted in an existing current differential protection algorithm configured to the DC transmission line can be eliminated effectively, influence due to ultra-long-distance line distribution parameters is eliminated, and meanwhile, setting time of tripping action is obviously reduced.

Description

technical field [0001] The invention relates to the technical field of relay protection for UHV DC transmission lines in electric power systems, in particular to the configuration principle of unitary protection for UHV DC transmission lines. Background technique [0002] In view of my country's "13th Five-Year Plan" and the environment of economic development in the future, energy consumption and resource development will face greater pressure. It can be seen from this that new energy grid-connected technology is an effective new measure widely used in domestic and foreign power systems to replace traditional power generation, save energy and reduce emissions. According to the actual situation of new energy power generation, wind power occupies the largest proportion. However, there are technical problems in the relay protection technology of UHV DC transmission lines used in the existing new energy grid connection, such as unreasonable protection configuration, defective ...

AI Technical Summary

Problems solved by technology

[0009] Why on the basis of so many relay protection configurations, the hidden danger of operation accidents still cannot be eliminated for DC transmission lines? In addition to the technical defects of the various protection principles mentioned above, the complexity of the DC transmission system also makes it impossible for any protection scheme to fully adapt to the various complex operating environments it faces, so there will inevitably be shortages of one kind or another

Traditional relay protection often lacks rigorous qualitative analysis conclusions and credible quantitative estimation results, so it has to rely on analysis conclusions based on ideal models, and through experimental simulation verification to actually adjust protection settings, without clear distinction boundaries and discrimination At the same time, the target of analysis is too monotonous, lacks correlation and contrast, once the measurement state of any one of the electrical signals changes, it will seriously distort the overall performance of the protection, so the relay protection—especially in the DC transmission system—delays become an indispensable means of compensation

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