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Performance Evaluation Method of Distance Protection in AC System Considering Hybrid DC Feed-in

A technology of distance protection and hybrid DC, which is applied in the direction of emergency protection circuit devices, electrical components, etc.

Active Publication Date: 2018-10-09
国家电网有限公司西南分部 +1
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Problems solved by technology

[0005] Aiming at the insufficiency of the existing technology that cannot analyze and evaluate the influence of the distance protection action characteristics of the existing AC system under the condition of simultaneous feed-in of two kinds of DC, the purpose of the present invention is to propose an AC-DC hybrid power grid distance An evaluation method of protection action characteristics, this method can take into account the impact of conventional DC transmission and flexible DC transmission on the measured impedance of distance protection under AC system faults

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  • Performance Evaluation Method of Distance Protection in AC System Considering Hybrid DC Feed-in
  • Performance Evaluation Method of Distance Protection in AC System Considering Hybrid DC Feed-in
  • Performance Evaluation Method of Distance Protection in AC System Considering Hybrid DC Feed-in

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Embodiment Construction

[0085] The present invention includes an evaluation method for the action characteristics of AC system distance protection under the action of a hybrid multi-infeed DC system. First, the conventional DC power transmission system and the flexible DC power transmission system are respectively equivalent to controlled current sources according to their respective operating characteristics, and then the transient The analysis principle calculates the short-circuit current at the AC system fault, and then obtains the equivalent circuit diagram when the AC system fails, and calculates the change in the characteristic quantity of the protection installation when the fault occurs from the fault component network diagram. Finally, based on the superposition theorem, the fault characteristic quantity of the installation place of the distance protection is solved and the evaluation of the action characteristics of the distance protection is given.

[0086] The equivalent controlled curren...

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Abstract

The invention discloses an evaluation method for distance protection performance of a mixed direct current feeding alternating current system. The method comprises the following steps: utilizing the characteristics of a mixed multi-feed direct current transmission system to enable a conventional direct current transmission system and a flexible direct current transmission system before the fault to be equivalent to a constant current source; enabling the conventional direct current transmission system and the flexible direct current transmission system after the fault to be equivalent to a controlled current source; subtracting the constant current source in a network before the fault from the controlled current source in the network under a normal condition after the fault equivalent to the conventional direct current transmission system and the flexible direct current transmission system in a fault component network; and adopting a transient state principle for acquiring a short circuit current at a fault point, thereby utilizing a superposition theorem to acquire the variation of voltage and current on a protecting mounting position in the fault component network, further acquiring the measured impedance and verifying the protection sensitivity. The defects of an evaluation scheme for the distance protection performance characteristics in a mixed multi-feed direct current transmission system model and an alternating current system connected with the mixed multi-feed direct current transmission system model in a traditional electrical power system equivalent model can be overcome.

Description

technical field [0001] The present invention relates to a method for evaluating distance protection of a hybrid multi-infeed direct current transmission system, and specifically refers to a method for analyzing and evaluating the action characteristics of distance protection when an AC power grid fails under the hybrid feed-in mode of a flexible direct current transmission system and a conventional direct current transmission system , belonging to the technical field of power system analysis. Background technique [0002] In recent years, with the implementation of west-to-east power transmission and the implementation of the global interconnected energy Internet strategy, HVDC transmission projects have developed rapidly in my country, and the AC-DC hybrid transmission system including conventional DC transmission and flexible DC transmission has gradually formed. Conventional DC transmission has unique advantages in realizing long-distance, large-capacity, asynchronous gri...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02J5/00
CPCH02H7/26H02J5/00
Inventor 张茜余锐欧阳金鑫马格土熊小伏肖超熊俊
Owner 国家电网有限公司西南分部
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