Two-control three-precharge phase-control switch circuit of switched capacitor bank

Abstract

The invention relates to a two-control three-precharge phase-control switch circuit of a switched capacitor bank, which comprises a three-phase zero switch which consists of two phase-control switches for pre-charging the capacitor bank, the input end of the two phase-control switches is connected with a casecade filtering circuit of a two-phase star connection, the output end of the two phase-control switches is connected with an LC filter circuit of a third phase after being connected with each other, the LC filter circuit of star connection is connected with a three-phase electric-net power source through a high-voltage fuse, and a phase control device independently controls the connection and the disconnection of the two phase-control switches at the peak point of the voltage according to the time order. A casecade circuit of a high-voltage silicon-stack diode and a high-voltage current-limiting resistor is connected with each phase-control switch in parallel so as to realize the pre-charging of the capacitor bank; and at the same time a casecade absorption circuit of RC is connected with each phase-control switch in parallel. The tested waveform shows that: the switching effect of the two-control three-precharge phase-control switch circuit can be switched one time without impact within one second like the TSC (thyristor switched capacitor bank), is free from the power consumption, adopts an ordinary switch as a phase-control switch, and has low cost.

Description

technical field [0001] The invention relates to a 2-control 3 pre-charging phase-controlled switch circuit for switching capacitor banks, which is used in the power quality control project of the power grid, and can realize fast and non-impact current input to the capacitor bank and cut off when the current crosses zero, belonging to the power system The field of reactive power compensation and harmonic filtering technology. Background technique [0002] The conventional circuit of switching capacitor bank is: mechanical contact switching switch, thyristor switching capacitor (TSC), synchronous vacuum switch. [0003] Mechanical contact switching switch, three-phase switch switches capacitors at random and uncertain grid voltage points, the current impact is large, and the rated current is at least a few times, causing grid voltage distortion. There is also a dangerous probability of bouncing of the closing mechanical contact and re-ignition of the open contact. The re-igni...

AI Technical Summary

Problems solved by technology

[0008] The invention creates a new type of switching circuit. Its positioning: reversing the situation that TCR+FC dominates the world in the field of medium voltage dynamic compensation; The slow speed limit of the control switch shortens the action time, and completes an action from opening to closing within 1 second. There is no current impact when closing, and the opening current is zero; the traditional three-phase phase control switch uses three The structure of the independent switch, only two independent switches are used to complete the three-phase switching action, which is called 2-control 3; the capacitor bank is pre-charged, and the switch is switched at the peak point of the voltage, and the switching accuracy is lower than that of the traditional phase-controlled switch. , the effect is better than the traditional phase control switch, which means low cost, high quality and easy acceptance by users

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