Overvoltage protection circuit

Abstract

The utility model discloses an overvoltage protection circuit, which comprises a power supply circuit breaker arranged in a power supply loop, and further comprises a piezoresistor, one end of the piezoresistor is connected with an outgoing line terminal of the power supply circuit breaker, and the other end of the piezoresistor is grounded; according to the utility model, equipment damage caused by branch loop overvoltage can be prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply and distribution in industrial enterprises, in particular to an overvoltage protection circuit. Background Art

[0002] Currently, industrial power supply and distribution facilities are prevalent with variable frequency equipment and pulse discharge devices. Traditionally, conventional power supply and distribution branch circuits only had overcurrent protection, using circuit breakers to prevent overcurrent. Overvoltage protection consisted of installing surge protectors (SPDs) in the incoming power lines to prevent lightning overvoltage. With the increasing diversity of electrical equipment, overvoltages in power supply and distribution branches are becoming increasingly common. These overvoltages are particularly severe due to unbalanced load distribution and resonance between energy storage components and the power supply frequency when connected in certain configurations. Temporary connection of electrical equipment often results in three-phase load imbalance, surge discharges during faults, and high-frequency harmonics generated during startup and shutdown. These can cause prolonged or transient overvoltages in the power supply circuit, potentially damaging the equipment within. Conventional power supply circuits utilize circuit breakers for short-circuit protection, while overvoltage protection for power supply circuits relies solely on surge protectors at the incoming power lines for lightning protection and grounding. Overvoltage protection for internal electrical equipment branch circuits is not provided. Utility Model Content

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide an overvoltage protection circuit, which can prevent the overvoltage in the branch circuit from damaging the equipment therein.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an overvoltage protection circuit, including a power circuit breaker arranged in a power supply circuit, and also including a varistor, one end of the varistor is connected to the output terminal of the power circuit breaker, and the other end of the varistor is grounded.

[0005] As a further improvement of the present invention, the varistor is arranged in a double-layer terminal block, and the two pins of the varistor are respectively welded to one end of the upper and lower layers of the double-layer terminal block. The upper terminal of the double-layer terminal block is connected to the output terminal of the power circuit breaker, and the lower terminal is grounded.

[0006] As a further improvement of the present invention, the double-layer terminal block is installed on a slide in the power box.

[0007] The beneficial effects of the utility model are:

[0008] The utility model is applied to the power supply and distribution branch circuit of industrial enterprises, and aims to protect the equipment in the branch circuit and prevent the overvoltage of the branch circuit from damaging the equipment therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the circuit structure of an embodiment of the present utility model. DETAILED DESCRIPTION

[0010] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0011] Example

[0012] An overvoltage protection circuit includes a power circuit breaker arranged in a power supply loop and a varistor, one end of the varistor is connected to an output terminal of the power circuit breaker, and the other end of the varistor is grounded.

[0013] In practice, the varistor can be placed in the empty space of a double-layer terminal block, with the two pins of the varistor soldered to one end of the upper and lower layers of the double-layer terminal block. When wiring, the upper terminal is connected to the output terminal of the power circuit breaker, and the lower terminal is grounded.

[0014] The principle of this embodiment is described below:

[0015] The characteristic of a varistor is that when the voltage difference between the two pins is within a certain range, the resistance of the varistor is infinite; when it exceeds the aforementioned range, the resistance is almost 0 and the two pins are conductive.

[0016] Install this protection circuit on the slide rail of the distribution box. One end of one layer of the double-layer terminal block is connected to the output terminal of the circuit breaker of the loop power supply, and one end of the other layer is connected to the ground wire.

[0017] The voltage between the two pins is the loop voltage. When there is no overvoltage in the loop, the varistor in the device does not conduct, and the distribution loop equipment works normally. When there is an overvoltage in the loop, the varistor conducts, and the power supply is equivalent to being directly grounded. The power circuit breaker will immediately disconnect the circuit because the power supply is short-circuited to the ground, protecting the equipment in the loop from damage caused by overvoltage in the loop.

[0018] like Figure 1 As shown, V1, V2, and V3 are simple overvoltage protection circuits. When overvoltage occurs in the load of the A1 / B1 / C1 circuit, one or more varistors in V1, V2, and V3 are turned on, causing one or more phases of A1 / B1 / C1 to be grounded. The power circuit breaker Q1 will disconnect the entire circuit, preventing the equipment in the Q3, Q7, and Q9 circuits from being damaged by high voltage.

[0019] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. An overvoltage protection circuit, comprising a power circuit breaker provided in a branch power circuit of an electrical device, characterized in that: It also includes at least one varistor, one end of each varistor is connected to the output terminal of the power circuit breaker, and the other end of each varistor is grounded; the varistor is arranged in a double-layer terminal block, and the two pins of the varistor are respectively welded to one end of the upper and lower layers of the double-layer terminal block, the upper terminal of the double-layer terminal block is connected to the output terminal of the power circuit breaker, and the lower terminal is grounded.

2. The overvoltage protection circuit according to claim 1, wherein: The double-layer terminal block is installed on a slide in the power box.

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