Power grid model of urban medium voltage distribution network

Abstract

The invention discloses a power supply grid model of a urban medium voltage distribution network. A medium voltage public spare line that spare allowance is In is added n the basis of a conventional basic cable grid model; provided that the rated carrying capacity of the maximum single-turn universal trunk line of some city is In, a no-load line that the rated carrying capacity is In can cooperatewith one or more conventional power supply grids in the city for power supply, so that the demand of an N-1 power-losing failure of any user of the power supply grid on the spare allowance can be satisfied, and subsequently, the spare demands of any medium voltage users in the whole city can be met. With the adoption of the medium voltage public spare line that spare allowance is In, the variousconventional basic grid models have the characteristics that the models are universal and the models can be combined and shared. Therefore, the power supply grid model of the urban medium voltage distribution network is universal, expansible, broad in adaption, economical and capable of achieving integration of new and old models and elastic supply; and the grid model has the characteristics of being high in reliability, strong in power supply capacity and low in construction cost.

Description

Technical field [0001] The invention relates to the technical field of power distribution networks, in particular to a power supply grid model of an urban medium-voltage power distribution network with high reliability, strong power supply capability and low construction cost. Background technique [0002] The typical cable grid model of the traditional medium-voltage distribution network in urban areas. The national distribution network industry standards used to recommend the use of five types: double injection, opposite injection, double ring, N supply and one backup, and single ring. use. Among them, the dual injection, opposite injection, and dual loop types are suitable for areas where dual power users are concentrated. The reliability of power supply is: N-1 (single-side power failure), 2 (users single-circuit inlet end failure). (Note: Two trunk cables are usually built together in the same pipe gallery. Failure of one of the trunk cables may cause simultaneous failure; ...

AI Technical Summary

Problems solved by technology

The power supply capacity is limited, and the backup margin is large

3) The versatility and expandability of the model are poor, and the choice of grid model is highly dependent on the certainty of urban planning and construction. Areas with many users of dual power sources; or the expected actual demand in areas where users of dual power sources are more concentrated are not as expected; or in the same grid model, the center of gravity of power consumption between the two power sources deviates from the expected value, etc.), all of which will result in preset power supply equipment Substantial changes or idleness of facilities, the performance of the actual use of the model is not ideal

4) The reliability of power supply does not meet the new needs of modern cities

Some models consider the backup after unilateral power supply failure; some models consider the backup after unilateral power supply and user incoming line failure, and lack the ability to comprehensively deal with user incoming line failure or failure of each section of the power supply trunk line

In addition, the power consumption of urban users is divided into multiple reliability levels. The overall reliability of power consumption in the city is not balanced, and the principle of fairness is lacking. Only by increasing investment can the reliability be improved to N-2 level at most, and the reliability level of power supply is still low, while Facilities and facilities have potential but are idle

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