CN207339261U - A kind of overvoltage protection device for preventing high pressure from sealing in electrification display - Google Patents

Abstract

The utility model provides an overvoltage protector for preventing high voltage from being connected to a charged display, which comprises a high voltage sensor and a charged display, an overvoltage protector is arranged between the high voltage sensor and the charged display, and the overvoltage protector uses a The copper circuit board is divided into three-phase input and three-phase output. Each phase circuit in the three-phase circuit is connected in series with two-stage current-limiting resistors R1 and R2. R1 and R2 are connected in series with each other. The front end of the first-stage current-limiting resistor R1 is connected with The high-efficiency discharge tube RV1 is connected with a piezoresistor RV2 at the rear end of the first-stage current limiting resistor R1, and is connected with a bidirectional transient suppression diode TV3 at the rear end of the second-stage current limiting resistor R2. The overvoltage protector uses three voltage limiting elements with different functional principles to limit the voltage in stages, two-stage resistance current limiting, and two groundings to ensure that the high-voltage sensor is under abnormal high voltage and limit the damage of the output voltage to the live display.

Description

An overvoltage protector for preventing high voltage from being connected in series to a charged display

technical field

The utility model relates to an electrical protection device, in particular to an overvoltage protector for preventing high voltage from being connected to a live display.

Background technique

At present, the small grounding power distribution network is usually 6kv, 10kv and 35kv level power grid system. The single-phase grounding non-fault phase voltage rises 1.732 times of the normal value. Three-phase short circuit or two-phase short circuit will occur for a long time, and high voltage will enter the secondary circuit. , the cable room of the closed high-voltage cabinet is closed due to the environment, and the high-voltage sensor is destroyed by the high voltage at the moment of short circuit, and the high voltage enters the charged display device, causing the charged display device to burn out, and affecting the relevant electrical operation circuit (switch opening and closing circuit), temperature and humidity test circuit, ventilation And the heating circuit, due to the high pressure, the above related circuit equipment will not be able to withstand the high pressure and burn down. According to the accident cases and a large amount of related data in recent years, it is found that the live display is installed in the high-voltage cabinet status display device or the high-voltage cabinet control status display device, and the high-voltage cabinet status display device contains switch cabinet position contacts, heaters, and cabinet fans. , temperature and humidity sensors, and even switch tripping and closing coil circuits. These circuits are very important. If high voltage enters, it will pose a threat to the operation of secondary equipment, cause protection malfunction or device burnout, and even cause personal injury to the personnel who are working. Life is threatened.

Utility model content

In order to overcome the deficiencies in the prior art, the utility model provides an overvoltage protector that prevents high voltage from being connected to a live display.

The utility model is realized through the following technical solutions: an overvoltage protector for preventing high voltage from being connected to a live display, comprising a high voltage sensor and a live display, an overvoltage protector is arranged between the high voltage sensor and the live display, the The overvoltage protector uses a copper-clad circuit board to divide three-phase input and three-phase output. In the three-phase circuit, each phase circuit is connected in series with two current-limiting resistors R1 and R2. R1 and R2 are connected in series with each other. A high-efficiency discharge tube RV1 is connected to the front end of the resistor R1, a varistor RV2 is connected to the rear end of the first-stage current-limiting resistor R1, and a bidirectional transient suppression diode TV3 is connected to the rear end of the second-stage current-limiting resistor R2.

In the above solution, the current limiting resistors R1 and R2 are 5W D4 3RO J cement resistors.

In the above solution, the high-efficiency discharge tube RV1 is a 2R300M/L high-efficiency discharge tube.

In the above solution, the varistor RV2 is a 2D391K varistor.

In the above solution, the bidirectional TVS diode TV3 is a 30KPA288CA bidirectional TVS diode.

In the above solution, the overvoltage protector is 50cm away from the high voltage sensor.

In the above scheme, the incoming terminal N-in and the outgoing terminal N-out of the overvoltage protector are respectively provided with grounding points at two different locations, and the grounding point at N-in is set in the cable room of the high-voltage cabinet, and the distance from the high-voltage sensor The grounding point is 80-100cm apart, and the grounding point at N-out is set in the cabinet under the circuit breaker room of the high-voltage cabinet, and the distance from the grounding point at N-in is 80-100cm.

Compared with the prior art, an overvoltage protector for preventing high voltage from being connected to a charged display in the utility model has the following beneficial effects:

The overvoltage protector uses three voltage limiting elements with different functional principles to limit the voltage in stages, two-stage resistance current limiting, and two groundings to ensure that the high-voltage sensor is under abnormal high voltage and limit the damage of the output voltage to the live display.

Description of drawings

Fig. 1 is an analysis diagram of the action principle of an overvoltage protector for preventing high voltage from being connected to a live display according to the utility model.

Figure 2 is a schematic circuit diagram of the overvoltage protector.

In the figure: 1. High voltage terminal, 2. High voltage sensor, 3. Overvoltage protector, 4. Live display, 5. Grounding point of high voltage sensor, 6. N-in grounding point, 7. N-out grounding point.

Detailed ways

A kind of overvoltage protector of the utility model that prevents high voltage from being connected to the charged display will be further described below in conjunction with the accompanying drawings and specific embodiments:

Fig. 1 is an analysis diagram of the action principle of an overvoltage protector for preventing high voltage from being connected to a live display according to the present invention, and Fig. 2 is a schematic circuit diagram of the overvoltage protector. In the figure, the overvoltage protector that prevents high voltage from being connected to the charged display includes a high voltage sensor 2 and a charged display 4, and an overvoltage protector 3 is arranged between the high voltage sensor 2 and the charged display 4, and the overvoltage protector 3 Use copper-clad circuit boards to divide three-phase input and three-phase output. Each phase circuit in the three-phase circuit is connected in series with two 5W D4 3RO J current-limiting resistors R1 and R2. R1 and R2 are connected in series with each other. A 2R300M/L high-efficiency discharge tube RV1 is connected to the front end of the current resistance R1, a 2D391K varistor RV2 is connected to the back end of the first-stage current-limiting resistor R1, and a 30KPA288CA bidirectional transient is connected to the rear end of the second-stage current-limiting resistor R2. state suppression diode TV3.

RV1 uses 2R300M/L high-efficiency discharge tube as the first-level protection element, and its breakdown voltage is 250V-345V; RV2 is a 2D391K varistor, which is used as the second-level protection element of the overvoltage protector device, and its protection voltage is 351V-429V; TV3 It is a bidirectional transient suppression diode 30KPA288CA, its working voltage is less than or equal to 288V; its breakdown voltage is 321V, and its clamping voltage is 470V. As a three-level protection element of overvoltage protector;

When a surge overvoltage signal appears at the secondary end of the high voltage sensor:

I. If the voltage amplitude is greater than the discharge value of the first-level components but less than the second- and third-level components, the RV1 high-efficiency discharge tube will be started first, and the overvoltage signal will be clamped between 250-345V to shunt and discharge most of the surge current. Discharge, absorb surge interference energy, and protect the charged display and related secondary equipment. The remaining residual pressure is completed by the last two levels of protection.

II. If the overvoltage amplitude is greater than that of the first-stage components and greater than the protective start-up voltage of the latter two-stage elements, because the latter two-stage elements have a fast start-up time, the latter two stages are discharged before the start-up. At this time, as the current of R2 increases, the RV2 terminal When the ground voltage rises to 351V, the RV2 varistor protection starts, clamping the voltage between 351V-429V, and protecting the TV3 tube and related secondary equipment. At this time, the overvoltage signal is still continuing, and the front-end voltage of R1 will continue to increase until it reaches the ignition discharge time of the RV1 discharge tube, and the RV1 ignition discharge will bypass the damaged current to the ground. The secondary output voltage of the sensor is finally clamped at about 250-345V, so as to protect the insulation of the overvoltage protector and the secondary wiring.

III. Installation location and installation requirements: The overvoltage protector is usually installed in the cable room of the high-voltage cabinet, preferably 50cm away from the high-voltage sensor. The N-in and N-out on the voltage protector are respectively set at two different grounding points, N The grounding point at -in is set in the cable room of the high-voltage cabinet, preferably 80-100cm away from the grounding point of the high-voltage sensor; the grounding point at N-out is set in the cabinet under the circuit breaker room of the high-voltage cabinet, at a distance of It is advisable to have a distance of 80-100cm between the grounding points; to connect to the main grounding network of the substation, use multi-strand hard and soft copper wires, and the wire diameter is not less than 4mm2.

The overvoltage protector uses three voltage limiting elements with different functional principles to limit the voltage in stages, two-stage resistance current limiting, and two groundings to ensure that the high-voltage sensor is under abnormal high voltage and limit the damage of the output voltage to the live display.

The above are only preferred embodiments of the utility model, and are not intended to limit the utility model in any form. Although the utility model has been disclosed as above with preferred embodiments, it is not intended to limit the utility model. Any Those who are familiar with this profession, without departing from the scope of the technical solution of the present utility model, can use the methods and technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all without departing from the scope of the present utility model For the content of the new technical solution, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present utility model still belong to the scope of the technical solution of the utility model.

Claims (7)

1. A kind of overvoltage protector that prevents high voltage from being strung into charged display, comprising high voltage sensor and charged display, is characterized in that: be provided with overvoltage protector between described high voltage sensor and charged display, described overvoltage protector uses The copper-clad circuit board is divided into three-phase input and three-phase output. Each phase circuit in the three-phase circuit is connected in series with two current-limiting resistors R1 and R2. R1 and R2 are connected in series with each other and connected at the front end of the first-stage current-limiting resistor R1. There is a high-efficiency discharge tube RV1, a varistor RV2 is connected to the rear end of the first-stage current limiting resistor R1, and a bidirectional transient suppression diode TV3 is connected to the rear end of the second-stage current limiting resistor R2. 2. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, wherein the current limiting resistors R1 and R2 are 5W D43RO J cement resistors. 3. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, wherein the high-efficiency discharge tube RV1 is a 2R300M/L high-efficiency discharge tube. 4. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, wherein the varistor RV2 is a 2D391K varistor. 5. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, wherein the bidirectional transient suppression diode TV3 is a 30KPA288CA bidirectional transient suppression diode. 6. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, wherein the overvoltage protector is 50 cm away from the high voltage sensor. 7. An overvoltage protector for preventing high voltage from being connected to a charged display according to claim 1, characterized in that: the incoming terminal N-in and the outgoing terminal N-out of the overvoltage protector are respectively provided with two The grounding point at different locations, the grounding point at N-in is set in the cable room of the high-voltage cabinet, 80-100 cm away from the grounding point of the high-voltage sensor, and the grounding point at N-out is set in the lower cabinet of the high-voltage cabinet circuit breaker room, at a distance of N- The distance between the grounding points at in is 80-100cm.