CN210041310U

CN210041310U - Shunting type electric fireproof load overcurrent protection device

Info

Publication number: CN210041310U
Application number: CN201921203166.8U
Authority: CN
Inventors: 王殊; 窦征
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-07-29
Filing date: 2019-07-29
Publication date: 2020-02-07
Anticipated expiration: 2029-07-29

Abstract

The utility model relates to a shunting electric fire prevention load overcurrent protection device belongs to civilian, industrial power consumption protection and electric fire prevention technical field. The device comprises a circuit breaker connected with a load in series, a current monitoring module and a normally open shunt switch connected with the load in parallel, wherein the signal output end of the current monitoring module is connected with a control module, and the open-close control end of the control module is connected with the controlled end of the shunt switch. Under normal conditions, the load circuit takes power from the power grid through a circuit breaker such as an air switch because the shunt switch is in an off state. When the load is in overcurrent or short circuit, the shunt switch is switched on within microsecond time, so that the overload or short-circuit current of the load loop is rapidly reduced. Adopt the utility model discloses can in time prevent the damage that the load circuit leads to because of overload or short-circuit current to effectively restrain overheated, electric arc and spark harm, ensure the safety in load circuit.

Description

Shunting type electric fireproof load overcurrent protection device

Technical Field

The utility model relates to an electric overload and short-circuit protection device, especially through reducing rapidly with electric circuit overload or short-circuit current, reduce the shunting electric fire prevention load overcurrent protection device of electric arc spark, belong to civilian, industrial power consumption protection and electric fire prevention technical field.

Background

The current overcurrent and short circuit protection in civil and industrial electric circuits generally adopts circuit breakers, wherein the most common circuit breaker is an air switch. When overcurrent or short circuit occurs in the circuit, the circuit breaker can automatically cut off the power supply.

According to the relevant regulations, the instantaneous opening time of the air switch is not greater than 0.1s, in practice within 10ms, which means that in the event of an overcurrent or short circuit, there is still an abnormally high current in the load circuit for 10ms to 100ms due to overload or short-circuit faults, and consequently overheating and strong arc sparks occur, with the result that it is possible to damage the load circuit (for example, to destroy the cable insulation, to burn the appliance or the circuit) and even to ignite combustibles, leading to fire.

Chinese utility model patent 201120189781.5 discloses a technical scheme that uses the electron cut-off switch module to replace the air switch circuit breaker, this electron cut-off switch establishes ties in the power consumption load return circuit, and when overload or short circuit fault took place, the time of disconnection power consumption return circuit shortened to microsecond level by the millisecond level, made load return circuit overheat time shorten, and only formed small electric arc spark. However, in the technical scheme, no matter the MOSFET tube or the thyristor is used as the electronic switch, a certain on-resistance exists, and the on-resistance of the general MOSFET tube is between tens of milliohms and hundreds of milliohms and is far larger than the contact resistance of the air switch, so that the problems of high heat generation and high power consumption exist, and the MOSFET is not suitable for the electric circuit with a large current load in practice.

Disclosure of Invention

The utility model aims to provide a: in view of the problems in the prior art, the shunt-type electric fireproof load overcurrent protection device can overcome the problems of heat generation and high power consumption of the electronic cut-off switch caused by internal resistance, and can rapidly reduce the current of a load loop in overload or short circuit, thereby preventing the load loop from overheating and reducing arc spark caused by overload and short circuit current, and more effectively protecting the load loop.

In order to achieve the above purpose, the utility model discloses shunting electric fire prevention load overcurrent protection device's basic technical scheme does: the intelligent control circuit comprises a circuit breaker connected with a load in series, a current monitoring module and a normally-open shunt switch connected with the load in parallel, wherein the signal output end of the current monitoring module is connected with a control module, and the opening and closing control end of the control module is connected with the controlled end of the shunt switch.

Under normal conditions, the load circuit takes power from the power grid through a circuit breaker such as an air switch because the shunt switch is in an off state. When the current monitoring module detects that overload or short-circuit current exists in a load loop, the control module quickly starts the shunt switch to be switched on within microsecond-level time according to an abnormal current signal. Because the shunt switch is connected with the load in parallel, the overload or short-circuit current generated by the load loop is rapidly reduced within microsecond time, so that the damage of the load loop caused by the overload or short-circuit current is prevented in time, and the overheating, the electric arc and the spark damage are effectively inhibited. Meanwhile, the large current generated by the short circuit of the shunt switch triggers the tripping action of a circuit breaker such as an air switch and the like, so that the power supply of the whole power utilization loop is cut off, and the safety of a load loop is ensured.

The utility model discloses a further perfection is, switching element in the shunt switch is silicon controlled rectifier, or MOSFET pipe, or IGBT component.

A further refinement of the present invention is that the control module comprises a single-chip microcomputer, or a digital signal processor, or a logic circuit, or an operational amplifier.

The utility model discloses it is still further perfect, the current monitoring module comprises hall current sensor chip.

The utility model discloses still further perfect is, shunt switch is parallelly connected the back each other by piezo-resistor, two positive and negative silicon controlled rectifiers or bidirectional thyristor switch device, parallelly connected constitution with the resistance-capacitance ware of establishing ties again.

The utility model discloses still further perfection is, control module's the switching device controlled end that the control end that opens and shuts connects shunt switch through optoelectronic coupling device.

Drawings

The present invention will be further described with reference to the accompanying drawings.

Fig. 1 is a circuit block diagram of an embodiment of the present invention.

Fig. 2 is a circuit schematic of the embodiment of fig. 1.

FIG. 3 is a circuit block diagram illustrating the operation of the embodiment of FIG. 1.

FIG. 4 is a block diagram of the second circuit in the working state of the embodiment shown in FIG. 1.

FIG. 5 is a block diagram of the three circuits in the working state of the embodiment of FIG. 1.

Detailed Description

Example one

The shunt type electric fire-proof load overcurrent protection device of the embodiment is basically composed as shown in fig. 1, wherein an air switch breaker and a current monitoring module are connected in series with a load, a normally open shunt switch is connected in parallel with the load, a signal output end of the current monitoring module is connected with a control module, and an opening and closing control end of the control module is connected with a controlled end of the shunt switch. The power supply module supplies power to the current monitoring module, the shunt switch and the control module.

Specifically, as shown in fig. 2, the current monitoring module is composed of a hall current sensor chip, the shunt switch is composed of two controllable silicon switching devices Q1 and Q2 which are connected in parallel in a positive and negative mode, the voltage dependent resistor VR1 and the capacitance resistance device R2 and C1 form a silicon controlled protection circuit, the control module is composed of a PIC12F1501 single chip microcomputer chip, and the pin 2 of the opening and closing control end of the control module is connected with the controlled ends of the two controllable silicon switching devices Q1 and Q2 in the shunt switch through a photoelectric coupling device U1. The power module B1 is used to supply power to the current monitoring module, the shunt switch, and the control module.

When the load circuit works, the current monitoring module collects the current of the load circuit and feeds the current signal to the control module, and the control module judges whether the load circuit is overloaded or short-circuited according to the current signal. The current monitoring module is composed of a Hall current sensor and can reliably respond to a current signal in real time. Mature products exist on the Hall current sensor market. The switching device in the shunt switch can be composed of a silicon controlled rectifier, a MOSFET tube or an IGBT element. The switching state of the shunt switching device is controlled by the control module.

The shunt switch is connected with the load in parallel and is in a disconnected state at ordinary times, the load work is not influenced, and when the load loop is in an overcurrent or short circuit state, the shunt switch is quickly connected and short circuits the load loop. The control module is composed of a microcontroller, and can adopt a single chip microcomputer or devices such as a digital signal processor, a logic circuit or an operational amplifier.

The microcontroller receives a load loop current signal output by the Hall current sensor, and when the current is overloaded or short-circuited, the control module controls the shunt switch to be switched on.

In a normal working state, as shown in fig. 3, an alternating current power supply voltage 220v is adopted for supplying power, the air switch is switched on, the shunt switch is switched off, the load loop supplies power normally, and the load obtains an alternating current 220v voltage.

Once the load is overloaded or short circuited, the protection state is divided into two phases as shown in fig. 4 and 5. The current monitoring module gives an abnormal large current signal, as shown in fig. 4, the control module sends a control signal to the shunt switch after receiving the signal, the shunt switch device is quickly conducted, and the voltage on the load is approximately 0V and the current of the load loop is very small because the load is short-circuited. Because the electronic circuit is adopted, the whole process is completed in microsecond level from the sampling of the current monitoring module to the conduction of the shunt switch device, the overload or short-circuit current and time of the load loop are greatly reduced, the overload or short-circuit current of the load loop is prevented from being overheated, and arc sparks are reduced. Then, the short-circuit current on the shunt switch triggers the tripping action of the air switch, and as shown in fig. 5, the current of the whole power utilization loop is cut off, so that the load circuit is protected, and the power utilization safety is ensured.

When the overload or short-circuit fault of the load circuit is removed, the air switch breaker is manually switched on, the load circuit recovers power supply and returns to the state shown in the figure 3. Because the air switch breaker widely used for the power supply line has small internal resistance and low heat productivity during normal work, the problems of heat generation and extra power consumption caused by replacing the air switch breaker with the electronic disconnecting switch module can be solved.

In a word, after the embodiment is adopted, the load loop can be prevented from being damaged by overheating or arc sparks generated by overload and short-circuit current as soon as possible, and the defects of self heating and large power consumption of the electronic cut-off switch can be overcome. In addition to the above embodiments, the present invention may have other embodiments. All the technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope claimed by the present invention.

Claims

1. The utility model provides a shunting electric fire prevention load overcurrent protection device, includes the circuit breaker who establishes ties with the load, its characterized in that: the current monitoring device further comprises a current monitoring module and a normally-open shunt switch connected with the load in parallel, the signal output end of the current monitoring module is connected with the control module, and the open-close control end of the control module is connected with the controlled end of the shunt switch.

2. The shunt type electrical fire protection load overcurrent protection device according to claim 1, wherein: and a switching device in the shunt switch is a silicon controlled rectifier, or an MOSFET (metal oxide semiconductor field effect transistor) or an IGBT (insulated gate bipolar transistor) element.

3. The shunt type electrical fire protection load overcurrent protection device according to claim 1, wherein: the control module is composed of a singlechip, a digital signal processor, a logic circuit or an operational amplifier.

4. The shunt type electrical fire protection load overcurrent protection device according to claim 1, wherein: the current monitoring module is composed of a Hall current sensor chip.

5. The shunt type electrical fire protection load overcurrent protection device according to claim 4, wherein: the shunt switch is formed by connecting a piezoresistor, two positive and negative silicon controlled or bidirectional silicon controlled switch devices in parallel and then connecting the piezoresistor, the two positive and negative silicon controlled or bidirectional silicon controlled switch devices in parallel with a resistor-capacitor device connected in series.

6. The shunt type electrical fire protection load overcurrent protection device according to claim 5, wherein: and the opening and closing control end of the control module is connected with the controlled end of the switch device of the shunt switch through a photoelectric coupler.