Direct-current circuit breaker capable of reducing forward superimposed current
A DC circuit breaker and superimposed current technology, which is applied in the direction of circuit devices, emergency protection circuit devices, electrical components, etc., can solve the problems of increased positive amplitude of superimposed current, large arc of circuit breaker opening, and difficulty in increasing large currents, etc. , to achieve the effect of preventing overvoltage, protecting the transformer, and eliminating the DC current component
Inactive Publication Date: 2014-11-12
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology
In terms of technical problems and reliability, the current superposition method is more feasible, that is, a forced reverse current or oscillating current is superimposed in the DC system to obtain the current zero point, but this method will increase the positive amplitude of the superimposed current at least more than double, which increases the difficulty of breaking large currents, which may cause larger arcs when the circuit breaker is opened, and cause greater damage to the switch contacts
Method used
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[0020] figure 1 The structures in are open and not limited to the ones shown in the figure. The present invention is described in more detail below by means of examples, but the following examples are only illustrative, and the protection scope of the present invention is not limited by these examples.
[0021] Such as figure 1 As shown, the DC circuit breaker provided by the present invention includes first and second inverter circuits 1, 1', first and second transformer circuits 2, 2', DC switch contacts 8 and non-linear resistors 9. The structures of the first and second inverter circuits 1 and 1' are all composed of a DC power supply 3, an inverter 4 and a filter 5. One end of the inverter 4 is connected to the DC power supply 3, and the other end is connected to the filter 5. The first and second transformer circuits 2 and 2' have the same structure, and both are composed of an intermediate frequency transformer 6 and a DC blocking capacitor 7, the output winding of the...
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The invention discloses a direct-current circuit breaker capable of reducing forward superimposed current. The direct-current circuit breaker comprises two inverter circuits, two transformer circuits and a direct-current switch contact, wherein the two converter circuits are respectively connected in series with the two transformer circuits and then are connected in parallel with two ends of the direct-current switch contact. The direct-current circuit breaker also comprises a nonlinear resistor which is connected in parallel with the direct-current switch contact. When the direct-current circuit breaker detects a heavy direct-current fault current, the two converter circuits are controlled to ensure that two manually generated alternating currents are superimposed onto the direct-current fault current, so that the amplitude of the forward superimposed current is reduced while a zero-crossing point is generated. A direct-current switch is triggered at a right moment during a current negative half wave cycle so as to enable the direct-current switch to be switched off, so that the generation of electric arcs is effectively inhibited, and the capacity of the circuit breaker is improved. According to different requirements, current waveforms generated by the inverter circuits can be flexibly controlled.
Description
technical field [0001] The invention relates to a DC circuit breaker, in particular to a DC circuit breaker capable of reducing forward superimposed current. Background technique [0002] At present, most of the DC systems in operation in the world use two-terminal systems. Due to the lack of practical high-voltage circuit breakers, the development level of DC circuit breakers has become an important factor restricting the development of DC transmission. So far, the method adopted in the design of DC circuit breakers in HVDC transmission systems is to convert the DC current passing through the AC circuit breaker into an AC current with a current zero point, so that the DC circuit breaker designed by the traditional AC circuit breaker The breaking scheme can achieve the effect of breaking a large current. In terms of technical problems and reliability, the current superposition method is more feasible, that is, a forced reverse current or oscillating current is superimposed ...
Claims
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IPC IPC(8): H02H3/087
Inventor 毛承雄王丹陆继明栾会
Owner HUAZHONG UNIV OF SCI & TECH