Contactless on-load automatic regulating distribution transformer

Abstract

The invention provides a non-contact on-load automatic voltage regulation distribution transformer, which includes a non-contact tap changer and a single-chip microcomputer control system. The high-voltage winding of the distribution transformer body has a rated voltage (UN) on the neutral point side. , 95%UN and 105%UN three taps, between each tap and the neutral point, a zero-crossing solid-state relay SSR as a non-contact tap changer is connected to measure the low-voltage side voltage output by the working power transformer T It is connected to the single-chip microcomputer monitoring system, and the output of the single-chip microcomputer monitoring system is connected to the control circuit of the solid-state relay SSR as a non-contact tap changer. The invention has the characteristics of automatically stabilizing the voltage according to the change of the load, has a compact structure and low cost, and adopts a solid-state relay instead of a bidirectional thyristor, so the operation is more reliable and the voltage stabilizing performance is better.

Description

(1) The technical field [0001] The invention relates to a distribution transformer, in particular to a distribution transformer with a certain automatic voltage stabilization function in a power system. (2) Background technology [0002] The vast majority (more than 99%) of the current distribution transformers use no-load, also known as non-excitation voltage regulation, that is to say, it is necessary to change the working taps of the high-voltage windings to achieve voltage regulation in a power outage state. When the transformer is overhauled, the position of the tap is re-determined according to the existing operating experience. In this way, the voltage of the secondary side of the distribution transformer changes greatly due to the fluctuation of the load every day, and the voltage is unstable. Only on-load voltage regulating switches are installed on and individual distribution transformers. Most of these switches are mechanical with contact or hybrid with contactle...

AI Technical Summary

Problems solved by technology

Although they can regulate the voltage on load and make the voltage on the secondary side of the transformer relatively stable, the structure of this kind of distribution transformer is complex, the volume is large and the reliability is low, and the cost is 50% higher than that of the distribution transformer with the same capacity without excitation voltage regulation. Even several times, and this kind of distribution transformer cannot operate frequently, and its performance is also poor

[0003] The invention patent document with the application number 98115448.4 discloses a technical solution named "non-contact electronic on-load voltage regulation device for power transformer". Irrelevant, its advantage is that the control circuit does not need to consider the withstand voltage problem of the control circuit when the high-voltage side is single-phase grounded, and when the voltage on the power supply side changes, it can realize on-load voltage regulation by detecting the voltage between the winding sub-connectors on the high-voltage side, but When the change of the transformer secondary side voltage caused by the load change, the control loop cannot respond, and the voltage fluctuation is mainly caused by the load change, so this kind of on-load voltage regulating device has poor voltage stabilization effect; on the other hand, it uses The bidirectional thyristor is used as a non-contact switch, which makes the control circuit complicated and reduces the reliability of the device; at the same time, this patent application uses the "transformer non-contact electronic on-load voltage regulating device" as an independent device, which is used in conjunction with the power transformer. The structure of the entire on-load tap changer transformer system is huge, and the cost is high, so it is not suitable for distribution transformers with small capacity.

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