CN-116230376-B - Hybrid on-load tap-changer

CN116230376BCN 116230376 BCN116230376 BCN 116230376BCN-116230376-B

Abstract

The application aims to provide a hybrid on-load tap-changer. The hybrid on-load tap-changer comprises a first gear circuit, a second gear circuit, a main on-off switch and a thyristor loop arranged between the first gear circuit and the second gear circuit, wherein the thyristor loop comprises a thyristor and a change-over switch, a first anode of the thyristor is connected with a voltage input end of the hybrid on-load tap-changer through the change-over switch, a second anode of the thyristor is connected with a voltage output end of the hybrid on-load tap-changer through the main on-off switch, and the thyristor loop is used for transitionally switching current from the first gear circuit to the second gear circuit when the gears are switched. By arranging the thyristor loop between the first gear circuit and the second gear circuit, the problems of overlong arc discharge and pre-breakdown existing in the switching process of the current are solved.

Inventors

XIAO YI
ZHU QIANG
WANG JUNJIE
XIE ZHIXUN
LIU BUFENG
XU KANGNING
HE CHUNHONG

Assignees

上海华明电力设备制造有限公司

Dates

Publication Date: 20260508
Application Date: 20230324

Claims (9)

1. The hybrid on-load tap-changer is characterized by comprising a first gear circuit, a second gear circuit, a main on-off switch and a thyristor loop arranged between the first gear circuit and the second gear circuit; The thyristor loop comprises a thyristor and a change-over switch, a first anode of the thyristor is connected with a voltage input end of the hybrid on-load tap-changer through the change-over switch, a second anode of the thyristor is connected with a voltage output end of the hybrid on-load tap-changer through the main on-off switch, and the thyristor loop is used for transitionally switching current from the first gear circuit to the second gear circuit when the gear is switched; the first gear circuit comprises a first main load circuit and a first transition circuit, wherein the first transition circuit is connected with the first main load circuit, the second gear circuit comprises a second transition circuit and a second main load circuit, and the second transition circuit is connected with the second main load circuit; the thyristor loop comprises a gate trigger circuit, the gate trigger circuit is connected with the thyristor, the gate trigger circuit comprises a switching switch, and the thyristor is turned on or off through the switching switch.
2. The hybrid on-load tap changer of claim 1, wherein a first static contact is disposed at an end of the first main load circuit at the voltage output end, and when the main on-off switch leaves the first static contact, a voltage difference is generated at two ends of the thyristor, and a trigger current is provided for a gate electrode of the thyristor through the gate trigger circuit, so that the thyristor completes a first conduction.
3. The hybrid on-load tap changer of claim 2, wherein the gate trigger circuit comprises a first trigger resistor and a second trigger resistor, the first trigger resistor is connected to the gate of the thyristor, and the thyristor is connected to the on-off switch through the first trigger resistor and the second trigger resistor.
4. A hybrid on-load tap changer as recited in claim 3, wherein the thyristor loop further comprises a gate protection circuit including a current limiting element, the gate of the thyristor being connected to the current limiting element by the first trigger resistor.
5. The hybrid on-load tap changer of claim 1, wherein the first transition circuit comprises a first transition resistor, the first gear circuit is provided with a second fixed contact at a voltage input end, the second gear circuit is provided with a third fixed contact at a voltage input end, when the thyristor is in a first conducting state, the gate trigger circuit is disconnected through the switching switch, so that the thyristor is automatically turned off after a zero crossing point, current is switched to the first transition circuit, when the current is switched to the first transition circuit, the change-over switch is switched from the second fixed contact to the third fixed contact, the thyristor is conducted through the switching switch, the second conducting of the thyristor is completed, and the first transition circuit and the thyristor form a first circulation.
6. The hybrid on-load tap changer of claim 5, wherein the first transition circuit is provided with a fourth stationary contact at a voltage output terminal, the second transition circuit is provided with a fifth stationary contact at a voltage output terminal, the main on-off switch is switched to the fourth stationary contact and the fifth stationary contact in the first circulating state, the thyristor is turned off by the on-off switch, and the first transition circuit and the second transition circuit form a second circulating current; The second transition circuit comprises a second transition resistor, a sixth static contact is arranged at a voltage output end of the second main load circuit, the change-over switch is switched from the third static contact to the second static contact in the second circulation state, the thyristor is conducted through the switching switch, the current is switched from the first transition circuit to the thyristor, the third conduction of the thyristor is completed, the current is switched from the first transition circuit to the thyristor, when the current is switched from the first transition circuit to the thyristor, the thyristor is disconnected through the switching switch, the current is switched to the second transition circuit, when the current is switched to the second transition circuit, the change-over switch is switched from the second static contact to the third static contact, the thyristor is conducted through the switching switch, and after the fourth conduction of the thyristor is completed, the thyristor is disconnected through the switching switch, and the current is switched from the thyristor to the second main load circuit.
7. The hybrid on-load tap changer of claim 1, wherein the thyristor loop comprises a snubber circuit connected in parallel with the thyristor, the snubber circuit comprising an snubber resistor and a capacitor arranged in series.
8. The hybrid on-load tap changer of claim 1, wherein the thyristor comprises a triac.
9. An on-load tap changer according to any one of the preceding claims 1 to 8, comprising a hybrid on-load tap changer.

Description

Hybrid on-load tap-changer Technical Field The application relates to the field of circuits, in particular to a hybrid on-load tap-changer. Background In the novel power distribution network, due to the wide application of new energy sources such as photovoltaics and wind power and the diversity of loads such as new energy automobiles, the requirement of users for the on-load voltage regulation function of the power distribution transformer is increasingly urgent. The existing on-load voltage regulating switch for the distribution transformer is mainly a hybrid scheme of matching a mechanical switch with a thyristor. The on-load tap-changer for the distribution transformer is divided into two modes of arc quenching in oil and vacuum arc quenching according to an arc quenching medium. The vacuum on-load tap-changer can generate interception during arc extinction, so that voltage overshoot is caused, and insulation damage of a tap winding of the transformer is caused when the voltage overshoot is serious. In addition, the contact opening distance in the vacuum arc-extinguishing chamber is obviously smaller than that in oil, and once vacuum failure occurs, short-circuit accidents are easy to occur, so that the requirement on process control is extremely high. In the traditional in-oil arc-quenching type on-load tap-changer, as the arc quenching process is completed by arc pulling of a mechanical contact in insulating oil, the contact can be seriously ablated after multiple times of switching, the insulating oil is decomposed under the action of an electric arc to generate combustible gas and trace metal particles, and therefore, the insulating oil and the electrode surface are required to be maintained regularly. Based on the in-oil arc-quenching type on-load tap-changer, problems such as overhigh cost, longer arc discharge and contact pre-breakdown exist. Disclosure of Invention It is an object of the present application to provide a hybrid on-load tap-changer. According to one aspect of the application, a hybrid on-load tap-changer is provided, the hybrid on-load tap-changer comprises a first gear circuit, a second gear circuit, a main on-off switch and a thyristor loop arranged between the first gear circuit and the second gear circuit, the thyristor loop comprises a thyristor and a change-over switch, a first anode of the thyristor is connected with a voltage input end of the hybrid on-load tap-changer through the change-over switch, a second anode of the thyristor is connected with a voltage output end of the hybrid on-load tap-changer through the main on-off switch, and the thyristor loop is used for transitionally switching current from the first gear circuit to the second gear circuit when the gear is switched. In some embodiments, the first gear circuit comprises a first main load circuit and a first transition circuit, the first transition circuit is connected to the first main load circuit, the second gear circuit comprises a second transition circuit and a second main load circuit, the second transition circuit is connected to the second main load circuit, the first gear circuit and the second gear circuit can be connected with a voltage output end of the hybrid on-load tap changer through the main on-off switch, the thyristor circuit comprises a gate trigger circuit, the gate trigger circuit is connected to the thyristor, the gate trigger circuit comprises a switching switch, and the thyristor is turned on or off through the switching switch. In some embodiments, a first static contact is disposed at one end of the first main load circuit at the voltage output end, and when the main on-off switch leaves the first static contact, a voltage difference is generated at two ends of the thyristor, and a trigger current is provided for a gate electrode of the thyristor through the gate trigger circuit, so that the thyristor completes a first conduction. In some embodiments, the gate trigger circuit comprises a first trigger resistor and a second trigger resistor, wherein the first trigger resistor is connected with the gate of the thyristor, and the thyristor is connected with the switching switch through the first trigger resistor and the second trigger resistor. In some embodiments, the thyristor loop further comprises a gate protection circuit comprising a current limiting element, the gate of the thyristor being connected to the current limiting element by the first trigger resistor. In some embodiments, the first transition circuit includes a first transition resistor, the first gear circuit is provided with a second fixed contact at a voltage input end, the second gear circuit is provided with a third fixed contact at a voltage input end, when the thyristor is in a first conducting state, the gate trigger circuit is disconnected through the switching switch, so that the thyristor is automatically turned off after a zero crossing point, current is switched to the first transition circuit, when the c