A Method for Discriminating Faulty Pole of HVDC Transmission Line Using Unipolar Electric Quantity

Abstract

The invention discloses a method for judging a faulty pole of a high-voltage direct current transmission line using unipolar electric quantity, comprising: step 1, obtaining an electric quantity signal from an electric quantity measuring device of the local pole direct current transmission line on the rectification side; step 2, obtaining an electric quantity signal according to step 1 Calculate the electrical quantity signal of the local pole line sudden change. When the sudden electric quantity of the local pole line is greater than the fault pole selection start threshold, perform step 3; step 3, use the electrical quantity signal obtained in step 1 to pass through a low-pass digital filter , to obtain the low-frequency electrical quantity of the DC transmission line at the local pole; step 4, compare the low-frequency electrical quantity of the local pole with the set fault pole selection threshold, and determine when the local low-frequency electric quantity is greater than the set fault pole selection threshold This pole is the fault pole of the transmission line. The invention only utilizes the electric quantity of the local pole of the high-voltage direct current transmission line to realize the discrimination of the faulty pole, does not require high sampling frequency, has simple algorithm, high sensitivity, and is easy to realize in engineering.

Description

【Technical field】 [0001] The invention belongs to the technical field of electric power system relay protection, and in particular relates to a method for discriminating a faulty pole of a high-voltage direct current transmission line using only unipolar electric quantity. 【Background technique】 [0002] HVDC power transmission system occupies an increasingly important position in long-distance and high-power transmission due to its advantages of large transmission power, low line cost, and good control performance. Developed countries in the world regard it as a large-capacity, long-distance power transmission It is also the main means of asynchronous networking, and it has also become a hot spot in power construction in my country because of "power transmission from west to east, mutual supply between north and south, and national networking". Since Gezhouba-Shanghai adopted DC transmission in 1989, the number of DC transmission projects in my country has ranked first in th...

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Problems solved by technology

However, the protection schemes proposed by the above studies all need the sampling information of the other pole or another circuit at the same time, and the action logic of the relay protection scheme is complex; Insufficient discrimination, which makes the relay protection scheme have insufficient sensitivity and reliability

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