Intelligent reactive compensation device based on single three-pole synchronous switch

Abstract

The invention provides an intelligent reactive compensation device based on a single three-pole synchronous switch. The intelligent reactive compensation device is characterized in that a capacitor bank consists of a reactor and a capacitor connected in a form of a triangular circuit; three main contacts of a three-pole synchronous switch K1 are mounted in the triangular circuit, and are serially connected with the capacitor bank; a pre-charging circuit (1) is connected between the input end and the output end of one main contact in parallel; a pre-charging circuit (2) is connected with the input end and the output end of another main contact in parallel; the capacitor bank is pre-charged by the line voltage of a grid through the pre-charging circuit (1) and the pre-charging circuit (2); a phase control device switches on and off the three main contacts of the three-pole synchronous switch K1 at the same time according to the phase angle of a predetermined grid voltage so as to switch the capacitor bank; and a CT (current transformer) is used for detecting the summation current in the triangular circuit for imbalance protection. The experimental waveform shows that the intelligent reactive compensation device provided by the invention is excellent in electric switching, green, energy-saving, simple in structure, economic and practical, and is good to wide engineering application.

Description

technical field [0001] The invention relates to the fields of reactive power compensation, harmonic filtering and grid power quality control of electric power systems, and in particular to an intelligent reactive power compensation device based on a single three-pole synchronous switch. Background technique [0002] The power grid needs reactive power compensation to achieve the purpose of stabilizing the grid voltage, improving the power factor, and reducing line loss. Switching capacitor bank is the main method to realize reactive power compensation. However, the technical status of switching capacitor bank is not optimistic. [0003] In the field of reactive power compensation, about 80% use mechanical contact switches to switch capacitors. The mechanical contact switches are three-pole switches. The three main contacts of the three-pole switch are closed and opened at the same time. The voltage phase angle switches the capacitor, and the current when it is switched in e...

AI Technical Summary

Problems solved by technology

The structure of three unipolar synchronous switches is more complicated than that of a single three-pole synchronous switch, and there are more driving circuits, and each unipolar switch requires an independent switch coil and driving circuit, and the driving sequence is complicated

However, the zero potential of the three-phase circuit of this circuit topology is prone to drift, and the DC potential of the capacitors in each phase of the capacitor bank is different, and it may be very high when it is abnormal, just like the phenomenon of voltage doubler rectification, which will affect the three-pole synchronization The potential of the main contact of the switch is not conducive to the safe operation of the system

Moreover, when the capacitor bank is in an unbalanced state, the sum of the currents of the three main contacts of the synchronous switch is still equal to zero according to Kirchhoff's current law, and it is not easy to observe the unbalanced situation of the capacitor bank

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