Method for judging pulse-losing faults of converter valves
A technology of lost pulse and converter valve, applied in electrical components, emergency protection circuit devices, etc., can solve the problems of malfunction of power frequency protection of ice melting device, difficult to distinguish ice melting device, and reduce the sensitivity of power frequency protection, etc. To avoid misoperation, improve the accuracy and speed of action
Active Publication Date: 2012-07-18
NR ELECTRIC CO LTD +1
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Problems solved by technology
[0007] Insufficiency of the existing judgment method: When the DC ice melting device melts ice on one of the double-circuit or multi-circuit AC lines paralleled on the same pole, the parallel lines will also be induced in the ice-melting AC lines. Larger AC current, so it is not easy to distinguish the pulse loss of the converter valve in the ice melting device or the normal induction of the parallel line, which may easily cause the power frequency protection (also known as 50Hz protection in China) of the ice melting device to malfunction
In order to avoid protection malfunction, the current method is to increase the value of ID_fund, but this will reduce the sensitivity of power frequency protection
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[0028] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.
[0029] The power frequency protection based on the fault characteristic method can be realized according to the present invention, as follows:
[0030] Read the DC voltage and DC current in real time and obtain the power frequency component through filtering, calculate formula (2) and formula (3), use figure 1 When the conditions are met, the power frequency protection will operate after a delay, and the delay is set according to the anti-shake time of avoiding the signal. The typical anti-shake time range is 2ms to 5ms.
[0031] figure 2 The logic block diagram shows: when ID_fund is greater than the current setting value and UD_fund is greater than the voltage setting value, the power frequency protection operates, otherwise the power frequency protection does not operate.
[0032] Setting value selection reference: When the DC i...
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The invention discloses a method for judging pulse-losing faults of converter valves. Power frequency protection consists of ID_fund of direct current in a direct current circuit of an ice-melting device and UD_fund of power frequency component of direct current voltage of the direct current output end of the ice-melting device. Current condition is that ID_fund is greater than a fixed current value, and voltage condition is that UD_fund is greater than a fixed voltage value. When the conditions are simultaneously satisfied, a converter valve is judged to have pulse-losing faults, and then power frequency protection acts. The method can accurately judge the pulse-losing faults of converter valves and can allow protection devices to effectively increase action precision and action speed ofpower frequency protection.
Description
technical field [0001] The invention relates to a method for judging a converter valve lost pulse fault and a relay protection device using the method. Background technique [0002] Icing of transmission lines in winter seriously threatens the safe operation of the power system. The successful development of the DC ice melting device has played a huge role in improving the power grid's ability to resist ice disasters. The basic principle of the DC ice-melting device is to use a converter valve to convert the AC current into a DC current, inject it into the AC wire, and use the DC current to generate heat in the wire resistance to melt the ice. [0003] When the converter valve loses the pulse fault, it will cause a large power frequency component in the DC ice melting current. The existing method for detecting the pulse loss fault of the converter valve is to detect the power frequency component in the DC current, and protect the pulse loss fault of the converter valve acc...
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IPC IPC(8): H02H7/10
Inventor 张翔田杰陈松林赵森林曹冬明
Owner NR ELECTRIC CO LTD