Single-phase-to-three-phase power supply system based on three-phase YNd transformer

Abstract

The invention discloses a single-phase-to-three-phase power supply system based on a three-phase YNd transformer. The system comprises a power transmission line, an isolation transformer, a power converter and a three-phase YNd transformer. The power transmission line is connected to a terminal P at the input end of the isolation transformer and a terminal A of a star-shaped winding of the three-phase YNd transformer. A terminal M and a terminal N at the output end of the isolation transformer are respectively connected with a terminal R and a terminal S at the input end of the power converter. A terminal B and a terminal C of the star-shaped winding of the three-phase YNd transformer are respectively connected with a terminal J and a terminal K at the output end of the power converter. Aterminal a, a terminal b and a terminal c of a triangular winding of the three-phase YNd transformer are connected with a low-voltage power distribution network with a grounded neutral point. A terminal Q of the isolation transformer and a terminal O at the center of the star-shaped winding of the three-phase YNd transformer are grounded. Therefore, single-phase power can be supplied to load operation needing three-phase power, and the system can be widely applicable to power distribution system transformation and fault repair.

Description

technical field [0001] The present application relates to the technical field of power distribution, in particular to a single-phase power-to-three-phase power supply system based on a three-phase YNd transformer. Background technique [0002] Users in the field of low-voltage power distribution in my country generally use single-phase power supply. When users need to use three-phase power, they need to re-erect power lines, which is very troublesome and takes a long time; Two-phase transmission lines and three-phase YNd transformers are connected to users, which is more economical and does not take up space, but some users need three-phase power. In particular, the user needs to use the 3-phase power supply for a short period of time due to special reasons, and the time for erecting a new three-phase line is not allowed. If the power quality of the grid allows, the three-phase power supply can be provided relatively easily, which will have a greater impact economic and soci...

AI Technical Summary

Problems solved by technology

The common reasons for disconnection in the distribution network are: (1) The wire joints are loose, especially when the copper and aluminum wires are connected, the contact surface will be galvanically corroded, which will increase the contact resistance and heat generation. The resistance is further increased, and such a vicious circle will inevitably blow the copper-aluminum spliced ​​joint; (2) When installing a fuse, one phase of the fuse is blown due to a certain phase being injured or the capacity of the three phases is inconsistent; (3) Switching or starting A certain phase contact of the equipment is burned, loose, or poor contact; (4) A certain phase of the motor winding is disconnected or the connector is loose, etc.

[0004] In the rural power grid, the users are scattered geographically, and some homes may have small workshops or small workshops, and the power system is sometimes set up with three-phase lines, but due to the low poles, one phase of the wire may be broken in bad weather conditions Or two-phase line, in the case of strong wind or rain, it is very dangerous to carry out emergency repairs

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