Adaptive current protection algorithm

A technology of current protection and protection algorithm, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems that the traditional current protection setting value cannot be changed, and the protection range changes.

Inactive Publication Date: 2016-05-04
HENNAN ELECTRIC POWER SURVEY & DESIGN INST
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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide an adaptive current protection algorithm. The present invention solves the technical problem that the traditional current protection setting value cannot change with the change of the system impedance, resulting in the change of the protection range when the system impedance changes.

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Embodiment Construction

[0067] Common short-circuit faults in power systems mainly include single-phase grounding, two-phase short-circuiting, two-phase grounding, and three-phase short-circuiting.

[0068] When an asymmetric short circuit occurs, negative sequence voltage and negative sequence current will be generated at the protective installation; when a grounding short circuit occurs, zero sequence voltage and zero sequence current will be generated at the protective installation. According to the analysis of the sequence network method, when a short circuit occurs, simply looking at the negative sequence network, its power supply is at the short circuit point, unlike the positive sequence network power supply at the system side of the protection installation. Calculate the system-side negative-sequence impedance based on the sequence voltage and negative-sequence current. Similarly, the system-side zero-sequence impedance can be calculated based on the zero-sequence voltage and zero-sequence cur...

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Abstract

The invention discloses an adaptive current protection algorithm. The adaptive current protection algorithm comprises the following steps: (1), when a short-circuit fault occurs, enabling a protective action program; (2), by the protective action program, extracting one or a half of cycle of protection-level voltage sampling data and protection-level current sampling data, and calculating three-phase voltage and current phasor; (3), calculating and extracting negative-sequence/zero-sequence voltage and current phasor in the one or half of cycle; (4), calculating system negative-sequence, zero-sequence impedance; (5), calculating a protected real-time setting value by utilizing the system negative-sequence, zero-sequence impedance, which are calculated in step (4) according to preset line impedance, system potential, opposite-side system impedance (only applied to zero-sequence current protection) and setting value calculation formulas; (6), comparing the real-time calculated setting value with the current phasor calculated in step (3), and judging whether protection can be enabled; if judging the protection can be enabled, tripping the protection. The adaptive current protection algorithm solves a problem that the current protection utilizes a fixed setting value, achieves relative fixation of a protection range and has a certain of popularization significance and practical significance.

Description

technical field [0001] The invention relates to a relay protection algorithm, in particular to a line current relay protection algorithm. Background technique [0002] The traditional current protection uses the system potential / (system impedance + line impedance of this section) to calculate the short-circuit current of this section of the line, and further calculates the protection setting value, so the protection setting value is fixed. When the system operation mode changes, the system impedance changes with the If the change occurs, since the setting value cannot change with the change of the system impedance, the protection range of the current protection will change at this time (the actual operation requirement of the power system is to hope that the protection range is relatively fixed), which is an inherent shortcoming of the current protection. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide an adaptiv...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26
CPCH02H7/262H02H7/263H02H7/267
Inventor 吴蕾于广耀陈萍徐荥冯蕾王瑞平周春晓毛吉亮黄晓博张晓慧李鹏达
Owner HENNAN ELECTRIC POWER SURVEY & DESIGN INST
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