CN113078613B - Fast electrical fire protection current limiting protection device - Google Patents
Fast electrical fire protection current limiting protection device Download PDFInfo
- Publication number
- CN113078613B CN113078613B CN202110378417.1A CN202110378417A CN113078613B CN 113078613 B CN113078613 B CN 113078613B CN 202110378417 A CN202110378417 A CN 202110378417A CN 113078613 B CN113078613 B CN 113078613B
- Authority
- CN
- China
- Prior art keywords
- circuit
- current
- microprocessor
- module
- output end
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000008859 change Effects 0.000 claims abstract description 66
- 238000001514 detection method Methods 0.000 claims abstract description 27
- 238000010606 normalization Methods 0.000 claims abstract description 20
- 239000003990 capacitor Substances 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 4
- 230000003993 interaction Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000000007 visual effect Effects 0.000 claims description 3
- 230000002265 prevention Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 3
- 230000001012 protector Effects 0.000 description 3
- 206010000369 Accident Diseases 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/027—Details with automatic disconnection after a predetermined time
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/04—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
本发明公开了快速电气防火限流保护装置，它包括过零检测模块、变化率归一化模块、微处理器、电流传感器、主控开关和负载电路.本装置将负载电流进行归一化处理，使得微处理器进行短路判断时所依据的实时归一化电流相对变化率drt的数值始终保持在0‑1之间，且无论负载额定电流为何值时阈值表是相同的，也即，当负载额定电流为10A或32A或63A等数值时，其标准归一化电流相对变化率drti的值均相同，无需针对不同的负载更换不同的限流保护装置，该装置即可适配大部分的额定电流的负载，尤其是64A以下的负载电路。
The invention discloses a rapid electrical fire prevention current limiting protection device, which comprises a zero-crossing detection module, a change rate normalization module, a microprocessor, a current sensor, a main control switch and a load circuit. The device normalizes the load current so that the value of the real-time normalized current relative change rate drt based on which the microprocessor makes a short-circuit judgment is always kept between 0 and 1, and the threshold table is the same regardless of the value of the load rated current, that is, when the load rated current is 10A, 32A or 63A, etc., the value of its standard normalized current relative change rate drti is the same, and there is no need to replace different current limiting protection devices for different loads. The device can adapt to most rated current loads, especially load circuits below 64A.
Description
Technical Field
The invention relates to a quick electric fireproof current-limiting protection device.
Background
In recent years, electric fire accidents in China have an ascending trend year by year, and according to statistics, the electric fire accounts for up to 30.2% of all kinds of fire accidents, wherein the serious and oversized electric fire accounts for 70% of the total number of the serious and oversized fire. In recent three years, electrical fires caused by electrical faults have occurred more frequently, resulting in tremendous personal casualties and property loss. However, as the electrified equipment in the building is complicated, fire phenomena caused by short circuit and overload of the electric appliances are more and more common, and related fire cases are also increased.
In actual lines, a fire caused by a local high temperature due to a short circuit, overload, or the like is called an overheat fire. The overheat fire protection technology is based on that the overcurrent protector cuts off the circuit when the current exceeds a given setting value, but because the action time of the overcurrent protector is between tens to hundreds of milliseconds, the current of the circuit is increased to hundreds times of rated current before the circuit is cut off, and fire is easily caused by high temperature.
Therefore, fire disasters caused by short-circuit faults are effectively avoided, and the key point is how to realize quick current limiting. When the circuit has short-circuit fault, the detection system can detect and break in extremely short time, so that the short-circuit current is limited to be several times of rated current and is limited and broken, the energy released by the short-circuit fault is effectively reduced, and the occurrence probability of electric fire is greatly reduced.
In order to realize rapid current limiting protection, the prior art judges short circuit by setting a related threshold value, and utilizes a rapid electronic switch to realize circuit breaking, such as real-time current value, change rate of a difference value of two adjacent load currents relative to time and the like, when an actually detected characteristic value exceeds a preset threshold value, a protector performs a breaking process.
For example, the chinese patent application number 201910504259.2, entitled a current-limiting type electrical fire-proof short-circuit protection device and short-circuit protection method, which uses comparing the time-related rate of change of the load current data difference value of two adjacent times with the reference rate of change to determine whether a short circuit occurs. The device has the following disadvantages:
1. Different loads and currents are different, different reference change rates, namely thresholds, are required to be set for different rated currents, and the universality is poor;
2. the change rate value calculated by the mode is larger, and noise is amplified;
3. the reference change rate, that is, the setting of the threshold value is affected by subjective factors, and usually the reference change rate, that is, the threshold value is a constant value set by a person, so that reliability is lacking, if the threshold value is set to be large, the detection time is prolonged, and if the threshold value is set to be small, misjudgment occurs.
Disclosure of Invention
The invention provides a quick electric fireproof current-limiting protection device, which overcomes the defects existing in the background technology. The technical scheme adopted for solving the technical problems is as follows:
The rapid electric fireproof current-limiting protection device comprises a zero-crossing detection module, a change rate normalization module, a microprocessor, a current sensor, a main control switch and a load circuit;
The zero-crossing detection module is used for detecting a zero-crossing signal of the load current, converting a sinusoidal signal of the load current into a square wave signal, connecting the square wave signal in parallel with the load circuit, and connecting the output end of the square wave signal with the microprocessor;
The current sensor is used for collecting the current of the load circuit and converting a load current signal into a voltage signal, the input end of the current sensor is connected in series in the load circuit, and the output end of the current sensor is connected with the input end of the change rate normalization module;
the main control switch is connected in series in the load circuit and is connected with the microprocessor, and the microprocessor controls the main control switch to be turned on or turned off;
The change rate normalization module is used for calculating the real-time normalized current relative change rate drt and transmitting the real-time normalized current relative change rate drt to the microprocessor, acquiring a load current value in real time according to a sampling time interval dt, subtracting the current value acquired at the last moment from the current value acquired at the current moment, taking an absolute value from the result, dividing the data after taking the absolute value by the sum of the absolute value of the current value at the current moment and the absolute value of the current value at the last moment, and finally obtaining the real-time normalized current relative change rate drt, wherein the output end of the change rate normalization module is connected with the microprocessor;
the microprocessor is internally provided with a threshold value table, wherein the threshold value in the threshold value table is a standard normalized current relative change rate drti obtained by dividing the absolute value of the difference between the current value and the previous time value of the standard sinusoidal signal by the sum of the absolute value of the current value and the absolute value of the previous time value;
And the microprocessor waits for a zero-crossing trigger signal, sets the real-time normalized current relative change rate drt received once every dt seconds, compares the real-time normalized current relative change rate drt with the corresponding standard normalized current relative change rate drti in the threshold value table, judges that a load circuit is short-circuited if the drt is received for more than drti continuously N times, and controls the main control switch to be disconnected so as to realize short-circuit protection.
In a preferred embodiment, the change rate normalization module includes a proportional circuit, a delay circuit, a subtracting circuit, a first precise full-wave rectifying circuit, a dividing circuit, an opening circuit, a second precise full-wave rectifying circuit, a third precise full-wave rectifying circuit and an adding circuit, wherein an input end of the proportional circuit is connected with an output end of the current sensor, an output end of the proportional circuit is connected with an input end of the delay circuit and an input end of the subtracting circuit, an output end of the delay circuit is connected with an input end of the subtracting circuit, an output end of the subtracting circuit is connected with an input end of the first precise full-wave rectifying circuit, an output end of the first precise full-wave rectifying circuit is connected with an input end of the dividing circuit, an input end of the second precise full-wave rectifying circuit is connected with an output end of the delay circuit, an output end of the third precise full-wave rectifying circuit is connected with an input end of the adding circuit, an output end of the adding circuit is connected with an input end of the dividing circuit, an output end of the dividing circuit is connected with an input end of the opening circuit, and an output end of the opening circuit is connected with a microprocessor.
In a preferred embodiment, the zero-crossing detection module comprises a voltage compensation circuit and a zero-crossing detection circuit, wherein the zero-crossing detection circuit adopts a high-speed photoelectric coupler for detection, the output end of the high-speed photoelectric coupler is connected with the microprocessor, the voltage compensation circuit is used for compensating the forward voltage drop of the high-speed photoelectric coupler, the input end of the voltage compensation circuit is connected with the load circuit in parallel, and the output end of the voltage compensation circuit is connected with the input end of the zero-crossing detection circuit.
In a preferred embodiment, the system further comprises a valid value acquisition module and a key input module:
the effective value acquisition module is used for processing the load current to obtain an effective value of the load current, the input end of the effective value acquisition module is connected with the output end of the current sensor, and the output end of the effective value acquisition module is connected with the microprocessor;
The key input module is used for setting a reference overload threshold value and controlling the reset of the main control switch, and is connected with the microprocessor;
Refreshing the collected current effective value once when the microprocessor passes through each half wave, refreshing the overload threshold value from the key input module once when the microprocessor passes through each half wave, comparing the current effective value with the overload threshold value, and judging that the load circuit is overloaded and controlling the main control switch to be disconnected by the microprocessor when the current effective value continuously exceeds the overload threshold value n times.
In a preferred embodiment, the effective value acquisition module comprises a low-pass filter circuit, a fourth precise full-wave rectifier circuit and a capacitance filter circuit which are sequentially connected in series, wherein the input end of the low-pass filter circuit is connected with the output end of the current sensor, and the output end of the capacitance filter circuit is connected with the microprocessor.
In a preferred embodiment, the system further comprises a display module for displaying the reference overload threshold and displaying whether the circuit is short-circuited or overloaded, and the input end of the display module is connected with the microprocessor.
In a preferred embodiment, the system also comprises an alarm module which is used for sending out an audible and visual alarm signal when the load circuit is short-circuited or overloaded, and the input end of the alarm module is connected with the microprocessor.
In a preferred embodiment, the system also comprises a communication module which is used for completing man-machine interaction and sending alarm information and is connected with the microprocessor.
In a preferred embodiment, the intelligent control device further comprises a driving module, wherein the input end of the driving module is connected with the microprocessor, and the output end of the driving module is connected with the master control switch.
In a preferred embodiment, the device also comprises an auxiliary power module which provides power sources with different voltage magnitudes for the whole device, and the output end of the auxiliary power module is connected with the microprocessor.
Compared with the background technology, the technical proposal has the following advantages:
1. The device normalizes the load current, so that the value of the real-time normalized current relative change rate drt according to which the microprocessor performs short circuit judgment is always kept between 0 and 1, and the threshold value table is the same no matter what value the load rated current is, namely, when the load rated current is 10A, 32A, 63A or other values, the value of the standard normalized current relative change rate drti is the same, and different current limiting protection devices are not required to be replaced for different loads, and the device can be suitable for most of the load of the rated current, especially for load circuits below 64A.
And the threshold value calculated by adopting the normalized current relative change rate is smaller, so that noise cannot be amplified and is not easy to be interfered by the noise.
Meanwhile, the standard normalized current relative change rate drti is adopted as a threshold value which is not a constant value, but is calculated according to the current value of the standard sinusoidal signal, and drti values at each moment are different, so that the real-time normalized current relative change rate drt is more similar to the corresponding standard normalized current relative change rate drti value, the phenomenon of misjudgment is not easy to occur, the reaction time for detecting and judging the short circuit of the load circuit by the microprocessor is shorter, the reaction time can reach 120us, and the reliability and the effectiveness of the detection result are improved.
2. The voltage compensation circuit is used for compensating the forward voltage drop of the high-speed photoelectric coupler, so that the square wave signal and the load current signal are strictly synchronous, no delay phenomenon occurs, and the strict correspondence of the real-time normalized current relative change rate drt and the standard normalized current relative change rate drti is ensured.
3. The effective value acquisition module can acquire the current effective value of the load, and the microprocessor can compare the current effective value with the overload threshold value to judge whether the load circuit is overloaded or not, so that the load circuit can be further protected.
Drawings
The invention is further described below with reference to the drawings and examples.
FIG. 1 is a schematic block diagram of a fast electrical fire protection and current limiting device according to a preferred embodiment.
FIG. 2 shows a circuit block diagram of the rate of change normalization module.
Fig. 3 shows a specific circuit diagram of the rate of change normalization module.
Fig. 4 shows a specific circuit diagram of the zero-crossing detection module.
Fig. 5 shows a circuit block diagram of the driving module.
Fig. 6 shows a specific circuit diagram of the effective value acquisition module.
Fig. 7 shows a waveform diagram of the normalized current relative change rate drti.
Detailed Description
In the claims, specification and drawings hereof, unless explicitly defined otherwise, the terms "first," "second," or "third," etc. are used for distinguishing between different objects and not for describing a particular sequential order.
In the claims, specification and drawings of the present invention, unless explicitly defined otherwise, references to orientation or positional relationship such as the terms "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. are based on the orientation and positional relationship shown in the drawings and are merely for convenience of description and to simplify the description, and do not indicate or imply that the apparatus or element referred to must have a particular orientation or be constructed and operated in a particular orientation, nor should it be construed as limiting the particular scope of the invention.
In the claims, specification and drawings of the present invention, unless explicitly defined otherwise, the terms "fixedly attached" and "fixedly attached" are to be construed broadly as any manner of connection without any positional or rotational relationship between the two, i.e. including non-removable, fixed, integrally connected, and fixedly connected by other means or elements.
In the claims, specification and drawings of the present invention, the terms "comprising," having, "and variations thereof as used herein, are intended to be" including but not limited to.
Referring to fig. 1 to 7, a preferred embodiment of the fast electrical fire protection and current limiting protection device includes a zero crossing detection module 5, a change rate normalization module 2, a microprocessor 10, a current sensor 1, a main control switch 6 and a load circuit.
The zero-crossing detection module 5 is configured to detect a zero-crossing signal of the load current, and convert a sinusoidal signal of the load current into a square wave signal, which is parallel connected to the load circuit, and an output terminal of which is connected to the microprocessor 10.
In this embodiment, the zero-crossing detection module 5 includes a voltage compensation circuit 51 and a zero-crossing detection circuit 52, the zero-crossing detection circuit 52 uses a high-speed photoelectric coupler to detect, an output end of the high-speed photoelectric coupler is connected with the microprocessor 10, the voltage compensation circuit 51 is used for compensating a forward voltage drop of the high-speed photoelectric coupler, an input end of the voltage compensation circuit is connected with the load circuit in parallel, and an output end of the voltage compensation circuit is connected with an input end of the zero-crossing detection circuit 52. As shown in fig. 4, the high-speed photocoupler employs a 6N137 chip.
The current sensor 1 is used for collecting current of a load circuit and converting a load current signal into a voltage signal, the input end of the current sensor is connected in series in the load circuit, and the output end of the current sensor is connected with the input end of the change rate normalization module 2.
The main control switch 6 is connected in series in the load circuit, and is connected with the microprocessor 10, and the microprocessor 10 controls the main control switch 6 to be turned on or turned off.
The change rate normalization module 2 is configured to calculate a real-time normalized current relative change rate drt and transmit the real-time normalized current relative change rate drt to the microprocessor 10, collect a load current value in real time according to a sampling time interval dt, subtract a current value collected at a previous time from a current value collected at a current time, take an absolute value from a result, divide the data obtained after taking the absolute value by a sum of the absolute value of the current value at the current time and the absolute value of the current value at the previous time, and finally obtain the real-time normalized current relative change rate drt, where an output end of the change rate normalization module is connected with the microprocessor 10;
The microprocessor 10 is built with a threshold table 3, where the threshold in the threshold table 3 is a standard normalized current relative change rate drti obtained by dividing the absolute value of the difference between the current value and the previous value of the standard sinusoidal signal by the sum of the absolute value of the current value and the absolute value of the previous value. As shown in fig. 6, the waveform diagram formed between the standard normalized current relative change rate drti and the time axis is the same regardless of the value of the current in the load circuit.
The microprocessor 10 waits for a zero-crossing trigger signal, sets the real-time normalized current relative change rate drt received every dt seconds, compares the real-time normalized current relative change rate drt with the corresponding standard normalized current relative change rate drti in the threshold value table, and if the drt is received for more than drti for N times, the microprocessor 10 judges that the load circuit is short-circuited, and controls the main control switch 6 to be disconnected to realize short-circuit protection.
Taking the current of 10A as an example in normal operation in the load circuit, if the standard normalized current relative change rate drti is 0.02 at a certain moment, but the load circuit is short-circuited at this moment and the current rises to 100A, the change rate normalization module 2 calculates that the real-time normalized current relative change rate drt= |100-10|/(|100|+|10|) = 0.818,0.818 is greater than 0.02, that is, the moment that the real-time normalized current relative change rate drt is greater than the corresponding standard normalized current relative change rate drti. If the microprocessor 10 receives signals N times continuously, and the real-time normalized current relative change rate drt is greater than the corresponding standard normalized current relative change rate drti, the microprocessor 10 determines that the load circuit is shorted, and the master switch 6 is turned off.
In this embodiment, as shown in fig. 2, the rate of change normalization module 2 includes a proportional circuit 21, a delay circuit 22, a subtracting circuit 24, a first precise full-wave rectifying circuit 26, a dividing circuit and an opening circuit 28, a second precise full-wave rectifying circuit 23, a third precise full-wave rectifying circuit 25 and an adding circuit 27, where the input end of the proportional circuit 21 is connected to the output end of the current sensor 1, the output end thereof is connected to the input end of the delay circuit 22 and the input end of the subtracting circuit 24, the output end of the delay circuit 22 is connected to the input end of the subtracting circuit 24, the output end of the subtracting circuit 24 is connected to the input end of the first precise full-wave rectifying circuit 26, the output end of the first precise full-wave rectifying circuit 26 is connected to the input end of the dividing circuit and the opening circuit 28, the input end of the second precise full-wave rectifying circuit 23 is connected to the output end of the delay circuit 22, the input end of the third precise full-wave rectifying circuit 25 is connected to the output end of the proportional circuit 21, the output end of the second precise full-wave rectifying circuit 23 is connected to the input end of the adding circuit 27, the output end of the adding circuit 27 is connected to the output end of the dividing circuit 28 and the output end of the opening circuit 28 is connected to the microprocessor 10.
And, the device also includes effective value acquisition module 4 and key input module 8:
the effective value obtaining module 4 is used for processing the load current to obtain an effective value of the load current, the input end of the effective value obtaining module is connected with the output end of the current sensor 1, and the output end of the effective value obtaining module is connected with the microprocessor 10;
The key input module 8 is used for setting a reference overload threshold value and controlling the reset of the main control switch 6, and is connected with the microprocessor 10;
The microprocessor 10 refreshes the collected current effective value once every half wave, meanwhile, the microprocessor 10 refreshes the overload threshold value from the key input module 8 once every half wave, compares the current effective value with the overload threshold value, and when the current effective value exceeds the overload threshold value for n times continuously, the microprocessor 10 judges that the load circuit is overloaded and controls the main control switch 6 to be turned off.
In this embodiment, the effective value obtaining module 4 includes a low-pass filter circuit, a fourth precise full-wave rectifier circuit and a capacitor filter circuit that are sequentially connected in series, an input end of the low-pass filter circuit is connected with an output end of the current sensor, and an output end of the capacitor filter circuit is connected with the microprocessor.
In this embodiment, the device further comprises a display module 11 for displaying the reference overload threshold and displaying whether the line is shorted or overloaded, and the input terminal thereof is connected to the microprocessor 10.
In this embodiment, the device further comprises an alarm module 12 for emitting an audible and visual alarm signal when the load circuit is short-circuited or overloaded, and the input end of the alarm module is connected to the microprocessor 10.
In this embodiment, the device further includes a communication module 13 for performing man-machine interaction and sending alarm information, which is connected to the microprocessor 10.
In this embodiment, the device further includes a driving module, an input end of the driving module is connected to the microprocessor, and an output end of the driving module is connected to the master control switch. As shown in fig. 6, the driving module includes a 2SD315AI chip 71, and a reset circuit 73, an RC network 72, a first peripheral protection circuit 74, and a second peripheral protection circuit 75, all connected to the chip 71.
In this embodiment, the device further comprises an auxiliary power module 9, which provides power sources with different voltage levels for the whole device, and the output end of the auxiliary power module is connected with the microprocessor 10.
The foregoing description is only illustrative of the preferred embodiments of the present invention, and therefore should not be taken as limiting the scope of the invention, for all changes and modifications that come within the meaning and range of equivalency of the claims and specification are therefore intended to be embraced therein.
Claims (10)
1. The rapid electric fireproof current-limiting protection device is characterized by comprising a zero-crossing detection module, a change rate normalization module, a microprocessor, a current sensor, a main control switch and a load circuit;
The zero-crossing detection module is used for detecting a zero-crossing signal of the load current and converting a sinusoidal signal of the load current into a square wave signal, the zero-crossing detection module is connected in parallel in the load circuit, the output end of the zero-crossing detection module is connected with the microprocessor, and the zero-crossing detection module outputs a zero-crossing trigger signal;
the current sensor is used for collecting the current of the load circuit and converting a load current signal into a voltage signal, the input end of the current sensor is connected in series in the load circuit, and the output end of the current sensor is connected with the input end of the change rate normalization module;
the main control switch is connected in series in the load circuit, and is connected with the microprocessor, and the microprocessor controls the main control switch to be turned on or turned off;
The change rate normalization module is used for calculating a real-time normalized current relative change rate drt and transmitting the real-time normalized current relative change rate drt to the microprocessor, the change rate normalization module acquires a load current value in real time according to a sampling time interval dt, subtracts the current value acquired at the last moment from the current value acquired at the current moment, takes an absolute value from the result, divides the data after taking the absolute value by the sum of the absolute value of the current value at the current moment and the absolute value of the current value at the last moment, and finally obtains the real-time normalized current relative change rate drt, and the output end of the change rate normalization module is connected with the microprocessor;
The microprocessor is internally provided with a threshold value table, wherein the threshold value in the threshold value table is a standard normalized current relative change rate drti obtained by dividing the absolute value of the difference between the current moment value and the previous moment value of the standard sinusoidal signal by the sum of the absolute value of the current moment value and the absolute value of the previous moment value;
And the microprocessor waits for a zero-crossing trigger signal, sets the real-time normalized current relative change rate drt received once every dt seconds, compares the real-time normalized current relative change rate drt with the corresponding standard normalized current relative change rate drti in the threshold value table, judges that a load circuit is short-circuited if the drt is received for more than drti continuously N times, and controls the main control switch to be disconnected so as to realize short-circuit protection.
2. The rapid electric fire protection and current limiting device according to claim 1, wherein the change rate normalization module comprises a proportional circuit, a delay circuit, a subtracting circuit, a first precise full wave rectifying circuit, a dividing circuit, an opening circuit, a second precise full wave rectifying circuit, a third precise full wave rectifying circuit and an adding circuit, wherein an input end of the proportional circuit is connected with an output end of the current sensor, an output end of the proportional circuit is connected with an input end of the delay circuit and an input end of the subtracting circuit, an output end of the subtracting circuit is connected with an input end of the first precise full wave rectifying circuit, an output end of the first precise full wave rectifying circuit is connected with an input end of the dividing circuit, an input end of the second precise full wave rectifying circuit is connected with an output end of the delay circuit, an output end of the third precise full wave rectifying circuit is connected with two input ends of the adding circuit, an output end of the adding circuit is connected with another input end of the dividing circuit, an output end of the dividing circuit is connected with an input end of the opening circuit, and an output end of the opening circuit is connected with a microprocessor.
3. The rapid electric fireproof current limiting protection device according to claim 1, wherein the zero crossing detection module comprises a voltage compensation circuit and a zero crossing detection circuit, the zero crossing detection circuit is detected by a high-speed photoelectric coupler, the output end of the high-speed photoelectric coupler is connected with the microprocessor, the voltage compensation circuit is used for compensating the forward voltage drop of the high-speed photoelectric coupler, the input end of the voltage compensation circuit is connected with the load circuit in parallel, and the output end of the voltage compensation circuit is connected with the input end of the zero crossing detection circuit.
4. The rapid electric fire protection apparatus of claim 1, further comprising an effective value acquisition module and a key input module:
The effective value acquisition module is used for processing the load current to obtain an effective value of the load current, the input end of the effective value acquisition module is connected with the output end of the current sensor, and the output end of the effective value acquisition module is connected with the microprocessor;
The key input module is used for setting a reference overload threshold value and controlling the reset of the main control switch, and is connected with the microprocessor;
Refreshing the collected current effective value once when the microprocessor passes through each half wave, refreshing the overload threshold value from the key input module once when the microprocessor passes through each half wave, comparing the current effective value with the overload threshold value, and judging that the load circuit is overloaded and controlling the main control switch to be disconnected by the microprocessor when the current effective value continuously exceeds the overload threshold value n times.
5. The device of claim 4, wherein the effective value acquisition module comprises a low-pass filter circuit, a fourth precise full-wave rectifier circuit and a capacitor filter circuit which are sequentially connected in series, wherein the input end of the low-pass filter circuit is connected with the output end of the current sensor, and the output end of the capacitor filter circuit is connected with the microprocessor.
6. The device of claim 4, further comprising a display module for displaying a reference overload threshold and a status of whether the circuit is shorted or overloaded, wherein an input of the display module is connected to the microprocessor.
7. The rapid electric fire protection and current limiting device according to claim 4, further comprising an alarm module for sending out audible and visual alarm signals when the load circuit is short-circuited or overloaded, wherein the input end of the alarm module is connected with the microprocessor.
8. The device of claim 7, further comprising a communication module for performing man-machine interaction and sending alarm information, wherein the communication module is connected to the microprocessor.
9. The device of claim 1, further comprising a drive module having an input coupled to the microprocessor and an output coupled to the master switch.
10. The rapid electric fire protection and current limiting device according to claim 1, further comprising an auxiliary power module, wherein the auxiliary power module provides power sources with different voltage levels for the whole device, and an output end of the auxiliary power module is connected with the microprocessor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110378417.1A CN113078613B (en) | 2021-04-08 | 2021-04-08 | Fast electrical fire protection current limiting protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110378417.1A CN113078613B (en) | 2021-04-08 | 2021-04-08 | Fast electrical fire protection current limiting protection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113078613A CN113078613A (en) | 2021-07-06 |
| CN113078613B true CN113078613B (en) | 2024-12-24 |
Family
ID=76615543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110378417.1A Active CN113078613B (en) | 2021-04-08 | 2021-04-08 | Fast electrical fire protection current limiting protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113078613B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN216872836U (en) * | 2021-04-08 | 2022-07-01 | 华侨大学 | A fast electrical fire protection current limiting device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1305598B1 (en) * | 1996-12-10 | 2001-05-09 | Abb Research Ltd | METHOD FOR THE RECOGNITION OF SHORT CIRCUIT CONDITIONS AND DEVICE THAT USES THIS METHOD |
| DE102004056436B4 (en) * | 2004-11-19 | 2019-04-04 | Jenoptik Advanced Systems Gmbh | Method and device for detecting residual current arcs in electrical circuits |
| US10566780B2 (en) * | 2014-11-19 | 2020-02-18 | Nanyang Technological University | Electronic circuit for single-event latch-up detection and protection |
| CN108899871B (en) * | 2018-05-08 | 2019-11-19 | 广东电网有限责任公司 | A kind of recognition methods of excitation surge current, device and computer-readable medium |
| JP7196716B2 (en) * | 2019-03-25 | 2022-12-27 | 東京電力ホールディングス株式会社 | Short-circuit monitoring device, short-circuit monitoring method, and program |
| CN110137900B (en) * | 2019-06-12 | 2020-01-21 | 福建省润泽智能科技有限公司 | Current-limiting type electrical fireproof short-circuit protection device and short-circuit protection method thereof |
| KR102198283B1 (en) * | 2020-06-09 | 2021-01-05 | (주)넥스트파워 | High-efficiency solar power system with micro-ground fault detection and blocking function |
-
2021
- 2021-04-08 CN CN202110378417.1A patent/CN113078613B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN216872836U (en) * | 2021-04-08 | 2022-07-01 | 华侨大学 | A fast electrical fire protection current limiting device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113078613A (en) | 2021-07-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103353570B (en) | Method and system for identifying arc fault based on load terminal voltage detection | |
| CN109417285B (en) | Direct current electric loop protection device and arc detection method | |
| CN102332699A (en) | Ground wire safety voltage control system | |
| KR102012420B1 (en) | DC arc breaking device including monitoring function | |
| CN201805222U (en) | Device for series arc fault detection using wavelet entropy | |
| CN102097780B (en) | Electric shock and electric leakage protection device for low voltage power grid | |
| CN203522122U (en) | Load line fault detection circuit applied to circuit breaker reclosing | |
| CN103439625A (en) | Cable system fault positioning and load monitoring method | |
| CN203415061U (en) | Intelligent electrical fire hazard monitoring device | |
| CN202159961U (en) | Ground wire safe voltage control system | |
| CN113078613B (en) | Fast electrical fire protection current limiting protection device | |
| CN101520484A (en) | Grounded failure detection and judgment of DC system | |
| CN216872836U (en) | A fast electrical fire protection current limiting device | |
| CN206533120U (en) | Switch cubicle arc light protecting system and feeder cabinet arc light protecting system | |
| CN204008808U (en) | Alternating current is scurried into the detection of straight-flow system and is compeled to jump device | |
| CN104330607B (en) | Alternating current scurries into the detection of straight-flow system and compels to jump device | |
| EP0414657A2 (en) | Electronic device for detection and storage of short circuit currents switched off by a power circuit breaker | |
| CN113589024B (en) | Rapid detection method and device for single alternating voltage measurement abnormality of redundant system | |
| CN109038517B (en) | Single-phase insulation type electric fire on-line prevention and control device and method | |
| KR101464246B1 (en) | Arc detection breaker using ZCT | |
| CN101550567A (en) | Method for protecting electrolyzer voltage and protective system | |
| CN210536284U (en) | Over-voltage and under-voltage protector for power supply | |
| CN205429692U (en) | Arc light ground protection controller device | |
| CN204270455U (en) | Electrical fire monitoring equipment | |
| CN109390915A (en) | Method of controlling security, equipment and its system of system with pre-charge circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |