Distance protection method making use of voltage distribution under distributed parameter model

Abstract

The invention discloses a distance protection method making use of voltage distribution under a distributed parameter model. The distance protection method comprises the following steps of: 1, taking a mutational volume current as a protection starting element: Img>0.2Ie (1), and when the mutational volume current meets the formula (1), judging that an mn power transmission line has a fault, wherein Img is the mutational volume current amplitude of the m end in the mn power transmission line, and Ie is the rated current amplitude; 2, solving the voltage amplitudes at 80% and 100% places of the line, for the fault phase, by combining a fault phase selection result and by utilizing the voltage of a relay-installed place under the distributed parameter model, and judging whether the voltage amplitudes accord with a formula (2): U1>=U0.81, wherein the U1 is the voltage amplitude at the 100% place of the line, and the U0.81 is the voltage amplitude at the 80% place of the line; and 3, if the formula 2 is set up, judging the fault is an internal fault and protecting actuating-tripping, or protecting non-actuating. The distance protection method disclosed by the invention is not influenced by distributed capacitive current of the line by adopting the distributed parameter model, has strong transition resistance endurance capability, capability of judging the fault just by judging the voltage trend at the terminal of the line and has less computation amount.

Description

【Technical field】 [0001] The invention belongs to the field of relay protection for power system transmission lines, and relates to a distance protection method based on a distributed parameter model, in particular to a high transition resistance protection method under the distributed parameter model. 【Background technique】 [0002] As a basic component of line protection, distance protection plays a vital role in the safe and stable operation of the power system. With the expansion of the power system scale, the high-voltage long-distance transmission lines are increasing day by day, and the requirements for distance protection are also getting higher and higher. [0003] The existing distance protection has the following problems: the centralized parameter model is adopted, and for ultra-high voltage long lines, its distributed parameter characteristics make the measured impedance of the traditional distance protection not proportional to the fault distance, which has a g...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a distance protection method using voltage distribution under a distributed parameter model, to overcome the shortcomings of traditional distance protection using a simplified model and poor resistance to transition resistance, and the existing distributed parameter model distance protection has a significant impact on the sampling frequency. Problems with high requirements, large amount of calculation, and low resistance to transition resistance

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