CN105281299A - Electrical cabinet arc light protection device and protection method - Google Patents

Abstract

An electric cabinet arc protection device and protection method, belonging to the field of power transformation equipment, comprising an arc sensor and a sound sensor, the arc sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged in a closed position in the electric cabinet, and the current sensor is arranged on the busbar After the connected transformer, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, and the collector, the current collector and the sound collector are respectively connected to Intelligent signal processor, the above-mentioned signal processor is connected to control the circuit breaker through the outlet relay. This method of parallel detection using multiple detection methods can prevent false detection, ensure the safety of electrical equipment, surrounding property and people, and can Avoid various life or property losses caused by fire.

Description

Arc protection device and protection method for electric cabinet

technical field

The invention relates to an arc light protection device and a protection method, in particular to an electric cabinet arc light protection device and a protection method, belonging to the field of electrical equipment.

Background technique

In recent years, the arc short circuit in the medium and low voltage switchgear of domestic substations with a voltage level of 35kV and below is one of the most serious faults in the distribution network, especially when it occurs inside the medium and low voltage switchgear. Due to the arc resistance The reason is that the short-circuit current often does not reach the over-current and quick-break setting value, and the fault cannot be cut off quickly. If the arc short-circuit fault of the switchgear cannot be cleared in time, it will develop into a medium-voltage bus fault, which may cause a power outage for important users, or even a "burning operation" accident in which multiple sets of switchgears are burned at the same time. The main transformer may also be affected by the external short-circuit current damage. Therefore, taking protective measures in the medium and low voltage switchgear of the substation, quickly detecting the arc light generated when the accident occurs and removing the fault in time will avoid or reduce the economic loss caused by the fault.

The energy generated by the arc can be as high as 8~60MW. It is mainly proportional to the burning time of the arc and the square value of the short-circuit current. Other factors affecting the burning time include the geometric size of the cabinet and the materials used. The arc burning duration exceeds 100ms, and the released energy begins to increase sharply. The cable starts to burn at about 150ms, the copper bar burns at about 200ms, and the steel (switchgear) starts to burn at about 250ms. At present, the domestic switchgear is basically designed according to the IEC-298 international standard, and its maximum internal arcing time is 100ms.

By using this kind of arc detection equipment that mainly uses arc light and overcurrent detection as auxiliary detection, the fire caused by arc light is greatly reduced. However, because some electrical equipment is installed in airtight or opaque places, in these The arc light that occurs locally, the photoelectric sensor is difficult to detect the arc light phenomenon, there are still some unsafe factors, how to eliminate the remaining unsafe factors is a problem that electrical technicians have always been concerned about.

Contents of the invention

In view of the fact that some electrical equipment is installed in airtight or opaque places, it is difficult for photoelectric sensors to detect the occurrence of arc light in these places, and there are still some unsafe factors. The present invention provides an electrical cabinet The purpose of the arc protection device and protection method is to increase the detection probability of arc detection, reduce accidents such as electrical equipment fires caused by arc light, and reduce losses caused by arc light.

The specific scheme of the present invention is: an electric cabinet arc protection device, including an arc sensor and a sound sensor. After the transformer and the circuit breaker in the electrical cabinet, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, the arc collector, the current collector and The sound collectors are respectively connected with intelligent signal processors, and the intelligent signal processors are connected to control the circuit breaker through the outlet relay, the arc collectors include photoelectric conversion amplifiers, the current collectors include current amplifiers, and the sound collectors The device includes an acoustic-electric conversion amplifier. The entrance of the intelligent signal processor is connected with the above-mentioned photoelectric conversion amplifier, current amplifier, and acoustic-electric conversion amplifier. A plurality of arc photoelectric sensors and sound sensors are arranged on the busbar and feeder of the electrical cabinet. The light-transmitting position is provided with a sound sensor, and the relay adopts a semiconductor solid-state relay.

An arc light protection method for an electric cabinet, comprising an arc light sensor and a sound sensor, the arc light sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged at a closed position in the electric cabinet, and the current sensor is arranged behind a transformer connected to a busbar and disconnected in the electric cabinet After the arc sensor, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, and the arc collector, the current collector and the sound collector are respectively connected to the intelligent Signal processor, the above-mentioned signal processor is connected to control the circuit breaker through the outlet relay, and the specific protection method adopts detection A system or detection B system:

1. The detection A system adopted is a protection method combining arc light and overcurrent detection. The specific action sequence is as follows:

A. The current sensor is a current transformer that collects the current value according to the set frequency;

B. The arc sensor detects the arc;

C. Perform photoelectric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected photoelectric signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. According to the signal sent by the intelligent signal processor, intelligent circuit breaker protection is performed on the corresponding position of the sensor. If more than half of the sensors have an open circuit signal, the main circuit breaker will be cut off;

2. The detection B system adopted is a protection method combining overcurrent and sound detection. The specific action sequence is as follows:

A. The current sensor, that is, the current transformer, collects the current value according to the set frequency;

B. The sound is the arc sound detected by the sensor;

C. Acoustic-electric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected acoustic and electrical signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. The signal of the intelligent signal processor performs intelligent circuit breaker protection on the corresponding position of the sensor. If more than half of the sensors have a circuit breaker signal, the main circuit breaker will be cut off.

The positive effects of the present invention are as follows: the electric cabinet arc protection device is equipped with three protection devices of sound, light and electricity, and in the circuit where the connecting line is exposed in the electric cabinet, arc detection is mainly used, and overcurrent detection is provided. The supplementary photoelectric detection method feeds back the detected arc light and overcurrent to the main body of the arc light protection device. After calculation, the information to be protected is transmitted to the outlet relay, and then the power is cut off; It is difficult to install arc sensors in these places, and it can be judged by sound sensors and over-current sensors. In this case, over-current is the main factor. According to the sound frequency of arc generation, the arc light in closed places Carry out detection and judgment, and then cut off the power supply through the circuit breaker to protect the circuit. This method of parallel detection by using multiple detection methods can prevent false detection, ensure the safety of electrical equipment, surrounding property and people, and avoid accidents caused by fire. Any loss of life or property.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic diagram of the circuit connection of the present invention.

detailed description

In order to better understand and implement the technical solution of the present invention, some embodiments of the present invention are provided here. These examples are for better explaining the technical solution of the present invention, and do not constitute any form of limitation to the present invention.

An electric cabinet arc protection device, comprising an arc sensor and a sound sensor, the arc sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged in a closed position in the electric cabinet, and the current sensor is arranged behind the transformer connected to the busbar and disconnected in the electric cabinet After the arc sensor, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, and the arc collector, the current collector and the sound collector are respectively connected to the intelligent A signal processor, the intelligent signal processor is connected to control the circuit breaker through the outlet relay, the arc collector includes a photoelectric conversion amplifier, the current collector includes a current amplifier, and the sound collector includes an acoustic-electric conversion amplifier, The entrance of the intelligent signal processor is connected with the above-mentioned photoelectric conversion amplifier, current amplifier, and sound-to-electricity conversion amplifier. Multiple arc photoelectric sensors and sound sensors are arranged on the busbar and feeder of the electrical cabinet, and sound sensors are arranged at closed or opaque positions. , the relay adopts a semiconductor solid state relay.

An arc light protection method for an electric cabinet, comprising an arc light sensor and a sound sensor, the arc light sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged at a closed position in the electric cabinet, and the current sensor is arranged behind a transformer connected to a busbar and disconnected in the electric cabinet After the arc sensor, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, and the arc collector, the current collector and the sound collector are respectively connected to the intelligent Signal processor, the above-mentioned signal processor is connected to control the circuit breaker through the outlet relay, and the specific protection method adopts detection A system or detection B system:

1. The detection A system adopted is a protection method combining arc light and overcurrent detection. The specific action sequence is as follows:

A. The current sensor is a current transformer that collects the current value according to the set frequency;

B. The arc sensor detects the arc;

C. Perform photoelectric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected photoelectric signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. According to the signal sent by the intelligent signal processor, intelligent circuit breaker protection is performed on the corresponding position of the sensor. If more than half of the sensors have an open circuit signal, the main circuit breaker will be cut off;

2. The detection B system adopted is a protection method combining overcurrent and sound detection. The specific action sequence is as follows:

A. The current sensor, that is, the current transformer, collects the current value according to the set frequency;

B. The sound is the arc sound detected by the sensor;

C. Acoustic-electric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected acoustic and electrical signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. The signal of the intelligent signal processor performs intelligent circuit breaker protection on the corresponding position of the sensor. If more than half of the sensors have a circuit breaker signal, the main circuit breaker will be cut off.

The specific technical solution of the present invention will be further described with reference to Fig. 1 and Fig. 2. In the figure, 1: busbar, 10: transformer, 100: main body of arc protection device, 200: arc sensor, 300: main current sensor, 300a: feeder Current sensor, 400: sound sensor, 500: arc collector, 500a: photoelectric converter, 600: current collector, 700: sound collector, 700a: acoustic-electric converter, 800: intelligent signal processor, 900: export relay , 1000: circuit breaker, 1000a: main circuit breaker.

In the existing technology, the detection signals of arc and current are generally used to judge whether to carry out circuit protection. However, in practical applications, due to the arc discharge that occurs in the enclosed area, it cannot be detected by the photoelectric sensor installed outside. It has been found that overcurrent can only be detected in the electrical circuit. According to the judgment of the prior art, it is impossible to accurately judge whether an arc has occurred by only relying on the overcurrent, and it will not cause the circuit breaker to operate. In the prior art, the arc signal is used as the Mainly, the overcurrent signal is used as a supplementary judgment. The arc that occurs in a closed area can only detect overcurrent. If you only rely on the result of overcurrent to cut off the circuit, it will inevitably lead to misjudgment. If you do not cut off the circuit, it will cause a certain amount of missed judgment. There will be some arc faults that cannot be detected. For this reason, in the present invention, in addition to being provided with an A detection system mainly based on arc detection and supplemented by overcurrent detection, an A detection system based on overcurrent detection and supplemented by sound is also provided. The auxiliary electroacoustic detection system B, in the B system, the B system is set according to the frequency of the sound when arc discharge occurs, and the comprehensive judgment is made by combining the detection results with the overcurrent.

Arc light medium and low voltage protection is mainly based on detecting the arc light emitted when an internal fault occurs in the switchgear. In addition, in order to prevent misoperation, overcurrent is used as the blocking condition, that is, the protection system issues a trip command only when arc light and overcurrent are detected at the same time, so With high-speed and reliable action performance. The total fault clearing time for each unit room of the switchgear can be guaranteed to be within 100ms, and a certain margin is left.

The electrical cabinet arc protection device main body 100 includes a power supply module connected to the bus bar, an arc collector 500 connected to the arc sensor, a current collector 600 connected to the main current sensor 300 and the feeder current sensor 300a, and an arc collector connected to the sound sensor 400 The sound collector 700, the intelligent signal processor 800 connected with the arc collector 500, the current collector 600, the sound collector 700, the circuit breaker 1000, and a power supply module.

The power supply module includes the transformer, A/D mode converter, etc. of the power used in the arc protection device of the electrical cabinet.

In the present invention, the voltage of the bus 1 is converted into a resistive transformer 10, and a bus break protector 1000a is connected between the current and the transformer 10.

The combination of the A system using photoelectric detection and the B system using electroacoustic detection can detect all arcs generated in the entire electrical cabinet, and can prevent problems before they happen.

Light waves have wave-particle duality. In arc light, there are abundant ultraviolet rays, and most of them belong to short-wave ultraviolet rays. Generally, the wavelength is in the range of 300-400nm. The detector in the present invention uses this characteristic of arc light to detect arc light. Compared with the general arc detector, this detection sensor has the characteristics of less detection errors. The protection range covered by the arc protection system is realized by arranging the physical position of the arc sensor. Therefore, its coverage is within the switch Inside the cabinet is unlimited. In addition, this protection system can also provide fault location function by detecting arc light information, so as to help find the fault point and carry out maintenance, and restore power supply as soon as possible. The arc protection system adopts a series of anti-interference measures such as signal isolation technology, software and hardware filtering, lightning protection, shielding and grounding.

The electronic components in the arc sensor 200 convert the light signal into an electrical signal, and transmit it to an intelligent signal processor for arc protection as required. The main body of the arc protection device acts on the protection device to trip after receiving the arc signal, combined with the overcurrent signal through logic judgment. The arc light detection uses the arc light sensor 200 and the optical fiber to transmit the light signal to the arc light collector 500, and the arc light sensor is a kind of light sensing element.

When a grounding or phase-to-phase short circuit fault occurs, the intensity of the light will suddenly increase due to the generation and burning of arc light. The arc light sensor 200 is installed in the relevant parts of the switch cabinet to monitor those fragile and important parts. Such as: switch cabinet commercial port busbar interval, switch cabinet lower CT and PT components, cable connectors, etc. In front of the sensor, its sensitivity is almost unchanged. On the back of the sensor, however, the sensitivity is somewhat reduced. The arc light sensor is installed in each compartment of the switch cabinet, which can provide selective protection for medium and low voltage switch cabinets ranging from simple to complex wiring. The arc light sensor, as a light sensing element, will detect the sudden increase in light intensity when an arc light fault occurs, and use the collector 500 to convert the light signal into a current signal and send it to the intelligent signal processor 800 . In the arc collector 500 there is a photoelectric converter 500a that converts optical signals into electrical signals, and then amplifies the electrical signals and transmits them to the intelligent signal processor 800 for intelligent calculation to obtain a result.

The arc frequency, overcurrent and sound thresholds are set in the intelligent signal processor 800 .

The main current sensor 300 and the feeder current sensor 300a in the present invention use current transformers, which transmit current signals to the current collector 600 at a certain frequency to amplify the electrical signals, and then use the intelligent signal processor 800 to perform calculations If the arc frequency and overcurrent calculation results are greater than the judged threshold current value, the intelligent signal processor 800 will pass the signal to the circuit breaker 1000 through the outlet relay 900 to cut off the generated arc and overcurrent. unit circuit to prevent fire. The action time provided by the protection using this principle is 2.5-7ms, plus the opening time of the circuit breaker is 35-60ms.

In a sealed system where it is difficult to install an arc sensor, or even if an arc phenomenon occurs, it is difficult to detect in a closed area, an acoustic sensor 400 that can detect the sound of discharge is installed near the area, and the signal detected by the acoustic sensor 400 is detected in the sound. In the collector 700, the acoustic-electric converter 700a, which converts the acoustic signal into an electrical signal, is amplified by an amplifier circuit and then transmitted to the intelligent signal processor 800 for processing. When the processed value is greater than the threshold value, Combined with the value of overcurrent, when the value that needs to cut off the power is reached, the intelligent signal processor 800 will pass the signal of cutting off the circuit through the outlet relay 900, and cut off the power of the circuit breaker 1000 in the line to protect the line A fire broke out. The outlet relay adopts a semiconductor solid state relay, the highest speed is 2ms, generally 7ms; the tripping outlet has a large capacity (250V, 5A), and does not need to be expanded through the intermediate relay; the arc protection unit can realize tripping, with flexible selectivity, and also With main trip function.

The action time provided by the protection using this new principle is 4.5-10ms, plus the opening time of the circuit breaker is 35-60ms, which can ensure the safety of equipment and people.

The intelligent signal processor can be a microcomputer, or a combination of related components of a single-chip microcomputer, and can also be processed by PLC or the like.

The above description is only about a single A system or B system. In fact, there are multiple sensors and related electrical components distributed in the entire electrical cabinet. Where arcing may occur, multiple sensors are set according to the detection range of the sensor. Similarly, relevant circuit protection circuit breakers are configured to ensure that the circuit in the area where the arc occurs can be cut off, thereby protecting electrical equipment.

For the detection of arc light and overcurrent in this device, the specific action sequence of system A is as follows:

A. The current sensor is a current transformer that collects the current value according to the set frequency;

B. The arc sensor detects the arc;

C. Perform photoelectric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected photoelectric signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. According to the signal sent by the sensor, intelligent circuit breaker protection is performed on the corresponding position of the sensor. If more than half of the sensors have a circuit breaker signal, the bus circuit breaker will be cut off.

For overcurrent and sound in this device, the specific action sequence according to system B is as follows:

A. The current sensor is a current transformer that collects the current value according to the set frequency;

B. The sound is the arc sound detected by the sensor;

C. Acoustic-electric conversion and electrical signal amplification;

D. The intelligent signal processor performs calculations on the collected acoustic and electrical signals and overcurrent signals, and compares the calculation results with the threshold;

E. Intelligent signal processor for logical judgment;

F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay,

G. According to the signal sent by the intelligent signal processor, intelligent circuit breaker protection is performed on the corresponding position of the sensor. If more than half of the sensors have an open circuit signal, the main circuit breaker will be cut off. (A sound sensor is drawn in this invention, in fact, there should be multiple sensors in the electrical cabinet)

When system A and system B detect signals at the same time, that is to say, when the three sensors detect arc signals at the same time, the system will also protect the circuit at the location according to the logic judgment method of system A or system B above.

The arc protection device of the electric cabinet is equipped with three protection devices of sound, light and electricity. In the circuit where the connecting line is exposed in the electric cabinet, a photoelectric detection method with arc detection as the main and overcurrent detection as the supplement is set. The detected arc light and overcurrent are fed back to the main body of the arc light protection device. After calculation, the information to be protected is transmitted to the outlet relay, and then the power is cut off. Another protection method is mainly aimed at closed places where the arc light is difficult to transmit to the outside. It is difficult to install arc sensors in these places, which can be judged by sound sensors and over-current sensors. Cut off the power supply and protect the circuit. This method of parallel detection using multiple detection methods can prevent false detection, ensure the safety of electrical equipment, surrounding property, and life, and avoid various life or property losses caused by fire.

After the various specific embodiments of the present invention have been described in detail above, those of ordinary skill in the art should clearly understand that various equivalent changes and equivalent replacements can be made according to the ideas of the present invention based on various common knowledge in the art. Or simple modifications, these should all belong to the scope of the technical solution of the present invention.

Claims (5)

1. An electric cabinet arc protection device, comprising an arc sensor and a sound sensor, characterized in that: the arc sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged at a closed position in the electric cabinet, and the current sensor is arranged on the transformer connected to the busbar and behind the circuit breaker in the electrical cabinet, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, the arc collector, the current collector and the sound The collectors are respectively connected with intelligent signal processors, and the intelligent signal processors are connected to control the circuit breaker through the outlet relay. 2. A kind of electric cabinet arc protection device according to claim 1, characterized in that: the arc collector includes a photoelectric conversion amplifier, the current collector includes a current amplifier, and the sound collector includes an acoustic-electric conversion amplifier , the entrance of the intelligent signal processor is connected with the above-mentioned photoelectric conversion amplifier, current amplifier, and sound-to-electricity conversion amplifier. 3. An electric cabinet arc protection device according to claim 1, characterized in that multiple arc photoelectric sensors and sound sensors are installed on the busbar and feeder of the electric cabinet, and sound sensors are arranged at closed or light-tight positions. 4. The arc protection device for electric cabinets according to claim 1, characterized in that: said relays are semiconductor solid state relays. 5. An electric cabinet arc protection method, comprising an arc sensor and a sound sensor, the arc sensor is arranged on the inner wall of the electric cabinet, the sound sensor is arranged in a closed position in the electric cabinet, and the current sensor is arranged behind the transformer connected to the busbar and the electric cabinet On the inner wall, the arc sensor is connected to the arc collector, the current sensor is connected to the current collector, the sound sensor is connected to the sound collector, and the arc collector, the current collector and the sound collector are respectively connected to the intelligent signal Processor, the above-mentioned signal processor is connected to control the circuit breaker through the outlet relay, and it is characterized in that: the specific protection method adopts detection A system or detection B system: 1. The detection A system adopted is a protection method combining arc light and overcurrent detection. The specific action sequence is as follows: A. The current sensor is a current transformer that collects the current value according to the set frequency; B. The arc sensor detects the arc; C. Perform photoelectric conversion and electrical signal amplification; D. The intelligent signal processor performs calculations on the collected photoelectric signals and overcurrent signals, and compares the calculation results with the threshold; E. Intelligent signal processor for logical judgment; F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay, G. According to the signal sent by the intelligent signal processor, intelligent circuit breaker protection is performed on the corresponding position of the sensor. If more than half of the sensors have an open circuit signal, the main circuit breaker will be cut off; 2. The detection B system adopted is a protection method combining overcurrent and sound detection. The specific action sequence is as follows: A. The current sensor, that is, the current transformer, collects the current value according to the set frequency; B. The sound is the arc sound detected by the sensor; C. Perform sound-to-electricity conversion and electrical signal amplification; D. The intelligent signal processor performs calculations on the collected acoustic and electrical signals and overcurrent signals, and compares the calculation results with the threshold; E. Intelligent signal processor for logical judgment; F. If a signal needs to be sent, the intelligent signal processor sends the signal to the exit relay, G. The signal of the intelligent signal processor performs intelligent circuit breaker protection on the corresponding position of the sensor. If more than half of the sensors have a circuit breaker signal, the main circuit breaker will be cut off.