A Thyristor Trigger Abnormal Protection Method for DC Transmission System
A DC transmission system and abnormal protection technology, applied in the direction of measuring electricity, measuring electrical variables, instruments, etc., can solve problems such as unrecognizable return inspection signals, degradation of thyristor withstand voltage performance, and inability to trigger abnormal protection for a single thyristor, so as to increase practicality The effects of high reliability, low requirements, and low calculation frequency
Active Publication Date: 2022-05-17
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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Problems solved by technology
The actual project uses the signal (back-check signal) established by detecting the positive or negative voltage of the thyristor to judge the thyristor-level fault. If there is no back-check phenomenon in multiple thyristors, the DC will be blocked directly. After being hit during the forward voltage period, when a certain blocking characteristic is restored during the reverse voltage period, the retest signal cannot identify this phenomenon
In addition, the pole control is equipped with commutation failure protection, which uses the characteristics of the difference between the current of the converter valve side and the DC current to identify the commutation failure after the commutation failure, but this protection is only for the triggering or commutation of the entire bridge arm of the converter valve process, unable to protect the abnormal triggering of a single thyristor
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[0051] Such as figure 1 As shown, this embodiment provides a thyristor trigger abnormality protection method in a direct current transmission system, the system frequency is 50 Hz, including the following steps:
[0052] Step 1, detecting the thyristor trigger pulse;
[0053] A. If the thyristor trigger pulse is detected, go to step 2;
[0054] B. If the thyristor trigger pulse is not detected, proceed to step 1;
[0055] Step 2. Intercept the thyristor voltage recording data U within 5ms after the thyristor trigger pulse appears 1 (t);
[0056] Step 3. Determine whether U is satisfied 1_max >k set_1 * U v_max ;
[0057] A. If satisfied, go to step 4;
[0058] B. If not satisfied, the thyristor has been triggered in advance, go to step 5;
[0059] Among them, U 1_max for U 1 The maximum value of the absolute value of (t), U 1_max =max(|U 1 (t)|); U v_max It is the maximum voltage that the thyristor can withstand in DC stable operation, U v_max =√2*U v / N, where U...
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The invention discloses a thyristor trigger abnormality protection method in a direct current transmission system, comprising: detecting the thyristor trigger pulse; intercepting the thyristor trigger pulse after T 1 Thyristor voltage recording wave data U 1 (t); judge whether U is satisfied 1_max >k set_1 * U v_max ;Judge whether there is |U 1 (t)|≤k set_2 * U 1_max ; Intercept T after the thyristor trigger pulse appears 1 to T 1 +T 2 Thyristor voltage recording wave data U 2 (t); judge whether |U exists 2 (t)|≥k set_3 * U 2_min ;Judge whether the number of abnormalities reaches the set value N SET ; Determine whether the protected thyristor device is triggered abnormally according to the above judgment result. The invention adopts the method of voltage comparison to identify abnormal triggering and shutting down of thyristors, reminds operating personnel of potential safety hazards when thyristors frequently appear abnormal, and directly blocks the converter valve when multiple thyristors appear abnormal.
Description
technical field [0001] The invention relates to a thyristor fault detection technology, in particular to a thyristor trigger abnormality protection method in a direct current transmission system. Background technique [0002] my country's DC transmission technology developed earlier. In the 1980s, the Zhoushan and Geshang DC projects were completed. In the early 21st century, the Tianguang, Sanchang, Gaozhao, and Xing'an DC projects were completed. In recent years, the construction speed of DC projects has been further accelerated. More than 30 DC projects are under construction or put into production. [0003] However, with the increase of the operating life of some DC projects, DC transmission equipment is aging, resulting in an increase in equipment operating loss and a decline in performance, which has caused serious safety hazards to the safe and stable operation of DC. The thyristor converter valve is the core equipment of the DC transmission project. The thyristor can...
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IPC IPC(8): G01R31/26G01R31/27
CPCG01R31/2601G01R31/27Y02E60/60
Inventor 武霁阳彭光强何竞松李清王越杨徐智华国建宝
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID