Power electronic transformer substation

Abstract

The invention provides a power electronic transformer substation. The high voltage side of the power electronic transformer substation is directly connected into a high voltage alternating current bus; one end of the low voltage side of the power electronic transformer substation is directly connected into a low voltage alternating current bus, the other end of the low voltage side of the power electronic transformer substation is directly connected into a low voltage direct current bus through a solid breaker; the high voltage alternating current bus comprises an alternating current inlet wire with a solid breaker; the low voltage alternating current bus comprises alternating current outlet wires provided with a solid breaker and a combination switch respectively; the low voltage direct current bus comprises a direct current outlet wire with a solid breaker; a control system of the transformer substation comprises a transformer substation dispatching layer, an inner-device coordination protecting layer and a single device control protecting layer. Compared with the prior art, the power electronic transformer substation has the advantages that rapid isolation of faults is achieved, the accurate control capability of power grids is improved, and the safe and stable operation level of the power grids is improved; meanwhile, an existing structure mode of the transformer substation is changed, the sizes of main devices are reduced, allocation of the main devices is simplified, the floor area is substantially reduced, and the good expandability is achieved.

Description

technical field [0001] The invention relates to a substation, in particular to a substation based on power electronics technology. Background technique [0002] A substation is a power facility in a power system that transforms voltage levels, receives and distributes electric energy, controls power flow, and adjusts voltage. It connects power grids at all levels of voltage through power transformers. Substations include power transformers, switchgear for opening and closing circuits, busbars for collecting current, transformers for measurement and control, instruments, relay protection devices, lightning protection devices, dispatching communication devices, and reactive power compensation equipment. [0003] Conventional substations include primary and secondary equipment. For primary equipment, single-phase or three-phase electromagnetic power transformers are generally used for voltage level conversion; electrical-mechanical circuit breakers are used to close or disconn...

AI Technical Summary

Problems solved by technology

[0013] This conversion and transmission mode has the following disadvantages: it requires a lot of equipment, the volume of the transformer is large, if the oil-immersed transformer is used, there will be oil pollution problems, and at the same time, the function is relatively single, and the control is not flexible. In order to improve the power quality, it is necessary to add other unnecessary power compensation or filtering device

[0015] In the context of the power system facing these new challenges, as the most basic power facility of the power system, its shortcomings are becoming more and more obvious due to its single function. The primary equipment of the substation is bulky and difficult to manufacture. The area of ​​the substation and land acquisition The investment is huge, and the insulating oil of the transformer poses a threat to the environment; the no-load loss of the transformer is high, and the output voltage fluctuates with the load; when a fault occurs on the load side, the transformer cannot isolate the fault and will spread to the power supply side; The current is coupled into the power grid through the transformer, which will cause pollution to the power grid; when the voltage on the power supply side is disturbed, it will be transmitted to the load side, resulting in an impact on sensitive loads; Will cause a large excitation inrush current

In addition, when the DC power transmission is operated in the single pole mode, the DC ground current passes through the neutral point of the power transformer, causing the partial magnetic saturation of the power transformer iron core, and the output harmonics, vibration and noise of the power transformer increase

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