Power distribution system

Abstract

The invention discloses a power distribution system. The system comprises a main power supply (20); the main power supply (20) is connected with at least two branch power supplies; the branch power supplies comprise a first branch power supply (21) and a second branch power supply (22); the first branch power supply (21) is connected with a phase-change switch (10), and the phase-change switch (10) realizes three-phase power supply unbalance switching of the first branch power supply (21); the second branch power supply (22) is connected to a second conductor (22-1) which is a flexible and / or rigid conductor and is directly or indirectly connected to at least one electrical device. According to the power distribution system, automatic phase-change switching is carried out through the phase-change switch connected with the first branch power supply, three-phase balance of current of the power supply system is achieved; the second branch power supply is arranged to shunt the main power supply, only part of current of the main power supply is converted during the phase change of the phase change switch, and three-phase balance of the current is better achieved.

Description

technical field [0001] The invention relates to the field of low-voltage electrical appliances, in particular to a power distribution system applied to unbalanced three-phase loads. Background technique [0002] In my country's current low-voltage power distribution three-phase four-wire power grid, single-phase loads account for the majority. These single-phase loads have large irregularities due to actual application conditions and time distribution, resulting in serious three-phase current imbalances in the power grid. Problems, it is easy to cause single-phase current or excessive central line, increase the copper loss and iron loss of the line and transformer, lead to line overload or short circuit, and even lead to high temperature and fire of the cable, causing fire accidents, which is not conducive to power supply safety. [0003] As a typical application to solve the three-phase unbalanced problem, the power distribution system applied to the unbalanced three-phase l...

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Problems solved by technology

[0002] In my country's current low-voltage power distribution three-phase four-wire power grid, single-phase loads account for the majority. These single-phase loads have large irregularities due to actual application conditions and time distribution, resulting in serious three-phase current imbalances in the power grid. Problems, it is easy to cause single-phase current or the center line is too large, increase the copper loss and iron loss of the line and transformer, cause the line to be overloaded or short-circuited, and even cause the cable to catch fire at high temperature and cause a fire accident, which is not conducive to the safety of power supply

[0003] As a typical application to solve the three-phase unbalanced problem, the power distribution system applied to the unbalanced three-phase load has been used more and more, among which the commutation switch is an important part of the power switching system. The existing three-phase The reversing switch for one-phase outgoing line usually uses three electromagnets to drive three sets of moving and static contacts, such as figure 1 In the Chinese patent 201610916682.X shown, the switch disclosed in this patent uses three electromagnets and three sets of dynamic and static contacts to realize three-way incoming lines and one-way outgoing line commutation; figure 2 The Chinese patent 201821456019.7 shown in the figure uses an electromagnet to drive a rotating plug-in contact to achieve phase change of three incoming lines and one outgoing line. The technologies of the above two patents both switch the full current of the power supply to Another phase line, this switching method often causes the current of the other phase line to be too high, resulting in a new current imbalance, which is not conducive to the balanced switching of the three-phase current of the system; in the case of a three-phase load, such as a three-phase motor , the full current switching of the above two patents will cause the phase sequence of the motor to change, which will cause the motor to reverse or stop, causing the motor to heat up and bring mechanical and electrical shocks at the same time, causing the motor to break and burn. Equipment damage and production economic loss

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