Thyristor trigger abnormity protection method for direct-current power transmission system
A DC transmission system and abnormal protection technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve problems such as the decline of thyristor voltage resistance, the inability to identify the back-check signal, and the inability of a single thyristor to trigger abnormal protection, etc., and meet the requirements. Low, increased practicality, low computational frequency
Active Publication Date: 2020-07-10
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 for a direct-current power transmission system. The thyristor trigger abnormality protection method comprises the steps of detecting thyristor trigger pulses; intercepting thyristor voltage recording data U1(t) in T1 time after thyristor trigger pulse occurs; judging whether U1 _ max is greater than kset _ 1 * Uv _ max or not; judging whether | U1 (t) | < = kset _ 2 * U1 _ max exists or not; intercepting thyristor voltage recording data U2(t) within the time from T1 to T1 + T2 after thyristor trigger pulses occur; judging whether | U2 (t) | is greater than or equal to kset _ 3 * U2 _ min or not; judging whether the abnormal frequency reaches a set value NSET or not; and determining whether the protected thyristor equipment is triggered abnormally or not according to the judgment result. According to the invention, a voltage comparison method is adopted to identify abnormal triggering, abnormal turn-off and otherphenomena of the thyristors, when the thyristors are frequently abnormal, an operator is reminded of potential safety hazards, and the converter valve is directly locked when a plurality of thyristorsare 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...
Claims
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Login to View More 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