Alternating-direct current mixed electric power system

Abstract

The invention discloses an alternating-direct current mixed electric power system. The system comprises an alternating current power supply (01), an alternating current bus (02), an alternating current feed line (03), an alternating current switch (04), an AC / DC current conversion device (05), an arc distinguishing device (06), a fault current damping device (07), a direct current positive electrode bus (101), a voltage measurement device (51), a direct current negative electrode bus (102), a voltage measurement device (52) and a grounding current measurement device (08). According to the invention, no transformer is connected between the AC / DC current conversion device (05) and the alternating current power supply (101), so the whole investment and land occupation of the system are reduced.

Description

technical field [0001] The invention relates to an AC-DC hybrid power system, which belongs to the technical field of AC-DC power supply. Background technique [0002] The transmission and distribution technology of the AC grid is mature, and the control and protection mechanism is clear. The DC power grid can realize the flexible control of the transmission power, is suitable for the access of DC power supply and DC load, and can be used as an important supplement to the urban power supply system. Building an AC-DC hybrid power supply system in a specific area can provide higher-quality power supply, better accommodate distributed power sources and DC loads, and improve the power and voltage control capabilities of the AC power distribution system, improve system security and stability, and reduce losses. . [0003] The voltage source converter device can realize AC / DC DC conversion, and its active and reactive power can be independently decoupled and controlled. It is th...

AI Technical Summary

Problems solved by technology

For the AC system using arc suppression coil grounding, the following problem exists when the converter device and the AC system share the ground, that is, after a ground fault occurs on the DC side of the converter device, the neutral point of the AC system will generate a DC bias voltage. A biased fault current will be generated on the arc suppression coil. Even if the converter device is blocked, the three-phase AC voltage can still be alternately conducted through the freewheeling diode of the converter. When the AC switch cannot be broken, the system cannot isolate the DC ground fault of the converter device

A large fault current will flow through the arc suppression device, commutation device and AC line, which will cause damage to the arc suppression coil, commutation device and other equipment in severe cases.

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