DC controllable lightning arrester device

Abstract

The invention provides a DC controllable lightning arrester device. The DC controllable lightning arrester device comprises a lightning arrester body and a hybrid switch, wherein the lightning arrester body comprises a lightning arrester fixed part and a lightning arrester controllable part, the lightning arrester fixed part and the lightning arrester controllable part respectively comprise at least one column of lightning arrester units, one end of a parallel circuit formed by the lightning arrester controllable part and the hybrid switch is grounded, the other end is connected with the lightning arrester fixed part, the hybrid switch comprises a thyristor valve switch and a mechanical switch which are connected in series, and the hybrid switch is connected with two ends of the lightningarrester controllable part in parallel. The DC controllable lightning arrester device is advantaged in that the thyristor valve switch and the mechanical switch are utilized to form the high voltage DC hybrid switch type controllable lightning arrester, the thyristor switch is ensured to be reliably turned off, so the lightning arrester returns to normal operation, the lightning arrester body achieves dual functions of energy release and overvoltage suppression, a charge rate of the whole lightning arrester under the operation voltage is reduced, the safety margin of the lightning arrester isimproved, and reliability of the lightning arrester is enhanced.

Description

technical field [0001] The invention relates to the field of electrical equipment in a power system, in particular to a DC controllable lightning arrester device. Background technique [0002] With the continuous improvement of DC transmission capacity, the characteristics of "strong DC and weak AC" appear, which will lead to a decrease in the short-circuit ratio, and the electrical distance between the inverter stations is relatively close. The failure of the AC system near the converter station may cause multiple DC circuits to occur at the same time The commutation failure affects the safe and stable operation of the AC and DC system. If the phase commutation on the inverter side fails, the power on the rectifier side cannot be sent normally, and the energy at the receiving end cannot be consumed normally, which will lead to system overvoltage. [0003] In the existing technology, the ZnO arrester is an ideal technical means to suppress overvoltage because of its good no...

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Problems solved by technology

[0002] With the continuous improvement of DC transmission capacity, the characteristics of "strong DC and weak AC" appear, which will lead to a decrease in the short-circuit ratio, and the electrical distance between the inverter stations is relatively close. The failure of the AC system near the converter station may cause multiple DC circuits to occur at the same time Commutation failure affects the safe and stable operation of AC and DC systems

If the commutation on the inverter side fails, the power on the rectifier side cannot be sent normally, and the energy at the receiving end cannot be consumed normally, which will lead to system overvoltage

[0003] In the existing technology, the ZnO arrester is an ideal technical means to suppress overvoltage because of its good nonlinear characteristics. However, in the DC system, when the commutation failure of the inverter side converter occurs, the When conventional surge arresters perform energy discharge and overvoltage suppression, the current flowing through the arrester is large and lasts for a long time (tens of milliseconds), and the energy that needs to be absorbed by the arrester reaches hundreds of megajoules. As far as the absorption capacity of the current ZnO resistor sheet is concerned, Hundreds of columns need to be connected in parallel, and the residual voltage is still high, the overvoltage limit level is difficult to meet the system requirements, and the charging rate is high under normal operating voltage, the aging speed of ZnO resistors is accelerated, and the reliability is reduced

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