An alternating current line fault intelligent protection device and method

Abstract

The application discloses an AC line fault intelligent protection device and method, characterized in that the device comprises a power supply module (1), an AC signal acquisition and processing module (2), a timing module and an AC fault protection module (3), wherein the timing module and the AC fault protection module (3) comprise a solid-state relay (J3), the output end of the solid-state relay (J3) is connected with the coil end of a magnetic latching relay (J2), the normally closed contact of the magnetic latching relay (J3) is connected with the coil end of a three-phase AC contactor (J1), the normally open contact is connected with a 24V power supply and a timing momentary switch (S3) respectively, and the timing momentary switch (S3) is connected with a timing module (W3). The device can protect high and low voltage AC lines with output power of thousands of watts to several megawatts. The fault protection reaction speed is extremely fast, the fastest fault protection speed of a conventional AC protector on the market is about 100 ms, and the fastest fault protection speed of the device can reach 16 ms by using an AC transformer for signal acquisition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fault protection of high-voltage alternating current lines, in particular to an intelligent protection device and method for alternating current line faults. BACKGROUND

[0002] At present, high-voltage alternating current plays a vital role in industrial production, but various major fires and other accidents caused by high-voltage alternating current short circuits often occur. Although there are various types of high-voltage alternating current fault protectors on the market, they still cannot meet the requirements of various industries in all aspects of industrial production. Therefore, it is necessary to develop an alternating current line fault intelligent protection device that can flexibly change its performance according to the specific situation and needs of industrial production, so as to better meet the needs of industrial production. SUMMARY

[0003] The purpose of the present application is to provide an intelligent protection device and method for alternating current line faults. It can protect the overcurrent, undercurrent and short circuit of the alternating current line, has fast response speed, and the voltage and current protection range is adjustable.

[0004] The present application achieves the purpose of the invention by adopting the following technical solutions:

[0005] An intelligent protection device for alternating current line faults, comprising a power supply module, an alternating current signal acquisition and processing module, a timing module and an alternating current fault protection module, the timing module and the alternating current fault protection module comprising a solid-state relay, the output end of the solid-state relay being connected to the coil end of a magnetic latching relay, the normally closed contact of the magnetic latching relay being connected to the coil end of a three-phase alternating current contactor, the normally open contact being connected to a 24V power supply and a timing momentary switch, respectively, the timing momentary switch being connected to the timing module, the magnetic latching relay being reset by a magnetic latching reset momentary switch, and the three-phase alternating current contactor being powered by a self-locking switch.

[0006] The above-mentioned intelligent protection device for alternating current line faults, wherein the alternating current signal acquisition and processing module is composed of an alternating current transformer and an alternating current signal processing module, the alternating current transformer being connected to the input end of the alternating current signal processing module, and the output end of the alternating current signal processing module being connected to the input end of the solid-state relay.

[0007] The above-mentioned intelligent protection device for alternating current line faults, wherein the power supply module comprises a DC power supply module and a 220V AC power supply self-locking switch.

[0008] The intelligent protection method for AC line fault, the AC transformer of the AC signal acquisition and processing module collects the AC current value in a half cycle, the AC signal processing module adds and averages the collected AC current value to obtain the effective value of each phase current, and the AC signal acquisition and processing module presets a normal current value range. When the effective value of the current of one phase is not in the preset normal current value range, the AC signal processing module sends a trip command.

[0009] The intelligent protection method for AC line fault, the trip command is transmitted to the magnetic latching relay coil end through the timing module and the solid-state relay output end of the AC fault protection module. Finally, the contacts of the magnetic latching relay are disconnected, the coil current of the three-phase AC contactor is disconnected, and the contacts of the three-phase AC contactor are disconnected, thereby disconnecting the AC line.

[0010] Compared with the prior art, the application has the following characteristics:

[0011] The device can protect high and low voltage AC lines with output power of thousands of watts to several megawatts. The fault protection reaction speed is extremely fast. The fastest fault protection speed of the conventional AC protector on the market is about 100ms, while the device uses an AC transformer to collect signals, and the fastest fault protection speed can reach 16ms, which is more than 5 times faster than the former. Therefore, it can provide excellent protection for high-power high-end equipment on the AC line. When the line fails, it can prevent equipment damage and fire accidents. Secondly, it is also very suitable for protection devices for verifying the load capacity limit of some high-power load equipment or AC contactors. When the high-power load equipment or AC contactors have overcurrent, undercurrent, short circuit, and contact sticking faults, because of the fast fault protection reaction speed, it can well protect the equipment or AC contactor from fire accidents. The AC fault intelligent protection device also has a normal operation timing function, so that test personnel can know when the test equipment or AC contactor fails. Because the protection device uses an AC transformer to collect high-voltage large current signals on the primary side and converts them into low-voltage small current on the secondary side and then transmits them to the protection system, it is safe.

[0012] The fault protection speed of the present technology is explained in detail as follows: Because ordinary AC power is a periodic sinusoidal signal, according to common sense, a complete cycle of current signal should be collected to accurately calculate the effective value of the current signal. For example, the most common 50Hz AC power in China has a complete cycle of 20ms. According to theory, at least 20ms of current signal should be collected to accurately calculate the effective value of the current.

[0013] But through the actual test verifies in the industrial production process 380 volts and above three-phase alternating current line appears the interphase short circuit fault time more than 20 ms, will cause fire, even explosion.If the prevention and control is not in place, will cause more serious disaster accident.

[0014] Based on the above reasons, the alternating current line fault intelligent protection device is used to avoid the short circuit of three-phase alternating current line as much as possible. The alternating current line fault intelligent protection device is used to make the fault protection time of the device less than 16 ms.

[0015] 1) Because the effective value of alternating current can be calculated according to the integral principle in higher mathematics, and the ordinary alternating current is a sinusoidal periodic signal, the alternating current signal processing module W2 is used to add and average the alternating current value collected by the alternating current transformer W1 in half a cycle, so that the effective value of each phase current can be accurately calculated. The alternating current signal acquisition time is reduced from 20 ms to 10 ms by using this scheme.

[0016] 2) The signal processing method adopted by the present application is to directly use the alternating current signal processing module W2 to add and average the alternating current value collected by the alternating current transformer W1 in half a cycle, so that the circuit module processing is simple, thereby making the signal processing time of the whole device controlled within 2 ms.

[0017] 3) The processing module and device selected by the present application are all aimed at improving the fault protection speed of the device. The whole device of electric signal transmission, processing, and alternating current line fault protection process takes only 6 ms through an alternating current transformer W1, an alternating current signal processing module W2, a solid state relay J3, a magnetic latching relay J2, and a contactor J1, which greatly guarantees the fault protection speed of the whole device.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1. High degree of intelligence, can quickly react to the overcurrent, undercurrent, short circuit and alternating current contactor life fault of the protected alternating current line, cut off the line current, and record the normal operation time of the protected alternating current line. The current range of the protected alternating current line is (10-1000) A, and the voltage range is (10-1000) Va.c.

[0020] 2. When the protected line fails, it can quickly cut off the protected line current, effectively prevent the high-end equipment on the line from being damaged and fire (the shortest time from the protected line failure to the cut-off of the protected line current is 16 ms, and the fault protection speed is more than 5 times faster than that of the alternating current protector on the market);

[0021] 3. Users can easily and quickly replace the high-voltage AC contactor according to production needs, thereby flexibly changing the protection range of the device's voltage and current (by replacing the high-voltage AC contactor, the device can be used with AC lines with a voltage of 1000Va.c., a single-phase current of 1000A, and an output power of up to 3 megawatts).

[0022] 4. The device is simple, safe, reliable, stable, and low in cost. Attached Figure Description

[0023] Appendix Figure 1 This is the circuit schematic diagram of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Example. An intelligent protection device for AC line faults, characterized in that it includes a power supply module 1, an AC signal acquisition and processing module 2, a timing module, and an AC fault protection module 3. The timing module and the AC fault protection module 3 include a solid-state relay J3. The output terminal of the solid-state relay J3 is connected to the coil terminal of a magnetic latching relay J2. The normally closed contact of the magnetic latching relay J3 is connected to the coil terminal of a three-phase AC contactor J1. The normally open contacts are connected to a 24V power supply and a timing jog switch S3, respectively. The timing jog switch S3 is connected to the timing module W3. The magnetic latching relay J2 is reset by closing the magnetic latching reset jog switch S1. The three-phase AC contactor J1 is powered by closing the self-locking switch S2.

[0026] The AC signal acquisition and processing module 2 consists of an AC transformer W1 and an AC signal processing module W2. The AC transformer W1 is connected to the input terminal of the AC signal processing module W2, and the output terminal of the AC signal processing module W2 is connected to the input terminal of the solid-state relay J3.

[0027] The power supply module 1 includes a DC power supply module VCC and a 220V AC power supply self-locking switch S4.

[0028] The AC line fault intelligent protection method involves the AC transformer W1 of the AC signal acquisition and processing module 2 acquiring the AC current value within half a cycle. The AC signal processing module W2 adds up the acquired AC current values ​​and takes the average value to obtain the effective value of the current of each phase. The AC signal acquisition and processing module 2 presets a normal current value range. When the effective value of the current of one phase is detected to be outside the preset normal current value range, the AC signal processing module W2 issues a trip command.

[0029] The trip instruction is transmitted to the coil end of the magnetic latching relay J2 through the output end of the solid-state relay J3 of the timing module and the alternating current fault protection module 3. Finally, the contacts of the magnetic latching relay J2 disconnect the coil current of the three-phase alternating current contactor J1, thereby disconnecting the contacts of the three-phase alternating current contactor J1, and further disconnecting the alternating current circuit.

[0030] Components: DC power module VCC, alternating current transformer W1, alternating current signal processing module W2, solid-state relay J3, magnetic latching relay J2, three-phase alternating current contactor J1, timing module W3, power self-locking switch S4, magnetic latching reset point switch S1, self-locking switch S2, timing point switch S3, and a plurality of wires.

[0031] Method for operating the device: when the device is connected to 220V alternating current, press the power switch S4, and the LED lamp on S4 is lit to provide normal power supply for the DC power module. Press the reset point switch S1 again, and the contacts of the magnetic latching relay J2 are reset. Then press the self-locking switch S2 that supplies power to the coil of the alternating current contactor J1. Then set the overcurrent and undercurrent values on the display screen of the alternating current signal processing module W2. Finally, press the timing switch S3, and the device starts normal operation.

[0032] Working principle: when the monitored alternating current circuit has a short circuit, overcurrent, or undercurrent fault, the alternating current transformer W1 converts the high-voltage large-current signal collected on the primary side into a low-voltage small-current signal on the secondary side and transmits it to the alternating current signal processing module W2. The alternating current transformer W1 collects the alternating current value within half a cycle. The alternating current signal processing module W2 converts the electrical signal into a digital signal through an AD converter and transmits it to a single-chip microcomputer. The single-chip microcomputer adds and averages the collected alternating current values to obtain the effective value of each phase current. The single-chip microcomputer performs logical judgment on the input effective value and the previously set current value range through a program. When the input digital signal value is not within the previously set current value range, the alternating current signal processing module W2 immediately sends a trip instruction to the solid-state relay J3. The trip instruction is transmitted to the coil end of the magnetic latching relay J2 through the output end of the solid-state relay J3. Finally, the contacts of the magnetic latching relay J2 disconnect the coil current of the three-phase alternating current contactor J1, thereby disconnecting the contacts of the three-phase alternating current contactor J1, and further disconnecting the alternating current circuit, thereby achieving the protection effect on the alternating current circuit. When the contacts of the magnetic latching relay J2 disconnect the coil current of the three-phase alternating current contactor J1, the timing stop circuit of the timing module W3 is also turned on, the timer stops timing, and the normal operation time of the protected alternating current circuit is continuously displayed.

[0033] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An intelligent protection method for AC line faults, characterized in that: The intelligent protection method for AC line faults is implemented using an intelligent protection device for AC line faults. The intelligent protection device for AC line faults includes a power supply module (1), an AC signal acquisition and processing module (2), a timing module, and an AC fault protection module (3). The timing module and the AC fault protection module (3) include a solid-state relay (J3). The output terminal of the solid-state relay (J3) is connected to the coil terminal of a magnetic latching relay (J2). The normally closed contact of the magnetic latching relay (J2) is connected to the coil terminal of a three-phase AC contactor (J1). The normally open contact is connected to a 24V power supply and a timing jog switch (S3). The timing jog switch (S3) is connected to the timing module (W3). The magnetic latching relay (J2) is reset by closing the magnetic latching reset jog switch (S1). The three-phase AC contactor (J1) is powered by closing the self-locking switch (S2). The AC signal acquisition and processing module (2) consists of an AC transformer (W1) and an AC signal processing module (W2). The AC transformer (W1) is connected to the input terminal of the AC signal processing module (W2), and the output terminal of the AC signal processing module (W2) is connected to the input terminal of the solid-state relay (J3). The AC current transformer (W1) of the AC signal acquisition and processing module (2) acquires the AC current value within half a cycle. The AC signal processing module (W2) adds up the acquired AC current values ​​and takes the average value to obtain the effective value of the current of each phase. The AC signal acquisition and processing module (2) presets the normal value range of the current. When the effective value of the current of one phase is detected to be outside the preset normal value range, the AC signal processing module (W2) issues a trip command.

2. The intelligent protection method for AC line faults according to claim 1, characterized in that: The power supply module (1) includes a DC power supply module (VCC) and a 220V AC power supply self-locking switch (S4).

3. The intelligent protection method for AC line faults according to claim 1, characterized in that: The trip command is transmitted to the coil of the magnetic latching relay (J2) through the output terminal of the solid relay (J3) of the timing module and the AC fault protection module (3); finally, the contacts of the magnetic latching relay (J2) disconnect the coil current of the three-phase AC contactor (J1), thereby disconnecting the contacts of the three-phase AC contactor (J1) and thus disconnecting the AC line.

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