Electricity utilization safety detector for electricity marketing

Abstract

The invention belongs to the technical field of power equipment, and particularly relates to an electricity utilization safety detector for electricity marketing, which comprises an electric leakage detection module for obtaining a detected voltage signal, the electric leakage detection module is connected with a zero-crossing comparator to compare the voltage signal with zero voltage, if the voltage signal is higher than the zero voltage, a high level is output to a single-chip microcomputer AT89C51, and if the voltage signal is lower than the zero voltage, the single-chip microcomputer AT89C51 is connected with the single-chip microcomputer AT89C51. The single-chip microcomputer AT89C51 counts the signals after receiving the signals and judges whether true electric leakage occurs or not, and if electric leakage is judged, the power-off protection module and the alarm module are started. The device can judge whether electric leakage occurs or not, power-off protection is carried out on an electric leakage circuit, after electric leakage, the buzzer gives an alarm, it is guaranteed that current can be rapidly cut off, danger is avoided, and personal safety is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to an electric power marketing electricity safety detector. Background Art

[0002] Power marketing refers to the process by which power companies adjust the demand level and time of the power market through a series of related business activities, meet users' reasonable power requirements with good service quality, achieve mutual coordination between power supply and demand, establish a partnership between power companies and users, and encourage users to actively change their consumption behavior and power usage methods, improve power efficiency, and thus increase corporate benefits. In power marketing, in order to ensure the normal use of power equipment, it is necessary to frequently use detectors to conduct power safety inspections on power equipment, so as to promptly detect abnormal power equipment and perform maintenance to ensure power safety.

[0003] As such a leakage detection device, a leakage detection device using a coupling capacitor is known. The leakage detection device comprises: a coupling capacitor, one end of which is connected to a DC power supply; a pulse generator, which provides pulses to the other end of the coupling capacitor; a voltage detection unit, which detects the voltage of the coupling capacitor charged by the pulse; and a leakage judgment unit, which compares the voltage detected by the voltage detection unit with a threshold value and judges whether the DC power supply has leakage based on the comparison result. Existing documents record leakage detection devices with such a structure. Existing technology is as follows: utilizing the stored energy of a filter capacitor in the power supply unit of an engine drive device, boosting the charging voltage of the capacitor by a power supply circuit and applying it between the engine coil and the ground, thereby detecting a decrease in insulation of the engine.

[0004] However, when detecting the presence or absence of leakage based on the voltage of the coupling capacitor, the magnitude of the voltage applied to the coupling capacitor affects the detection accuracy. If the voltage Va of the coupling capacitor is small, when the leakage resistance between the DC power supply and the earth changes due to temperature, etc., the change amplitude α of the capacitor voltage also becomes small. In other words, since the dynamic range cannot be increased, there is an upper limit to the detection accuracy. On the other hand, if the voltage Vb of the coupling capacitor is large, the change amplitude β of the capacitor voltage becomes larger relative to the change of the leakage resistance. In other words, since the dynamic range can be increased, the detection accuracy is improved.

[0005] When detecting leakage based on the voltage of the coupling capacitor, the magnitude of the voltage applied to the coupling capacitor affects the detection accuracy. If the voltage Va of the coupling capacitor is small, the change amplitude α of the capacitor voltage also decreases when the leakage resistance between the DC power supply and the earth changes due to temperature, etc. In other words, since the dynamic range cannot be increased, there is an upper limit to the detection accuracy. Summary of the invention

[0006] The purpose of the present invention is to provide an electric power marketing electricity safety detector to address the problems existing in the prior art. The detector can determine whether there is a leakage and cut off the power to the leakage circuit. After the leakage, the buzzer will sound an alarm to ensure that the current can be quickly cut off to prevent danger and ensure personal safety.

[0007] The technical solution of the present invention is:

[0008] The utility model discloses an electric power marketing electricity safety detector, which adopts a direct current power supply to power the system, and comprises a leakage detection module for obtaining a detected voltage signal. The leakage detection module is connected with a zero-crossing comparator to compare the voltage signal with the zero voltage. If the voltage is higher than the zero voltage, a high level is output to a single-chip microcomputer AT89C51. After receiving the signal, the single-chip microcomputer AT89C51 counts the signal to determine whether there is a real leakage. If it is determined that there is a leakage, a power-off protection module and an alarm module are started.

[0009] Specifically, the leakage detection module adopts the principle of electromagnetic induction, passes the output current and input current wires through a ring-shaped magnetic core at the same time as a primary mutual inductance coil, generates a magnetic field according to the changing current, and obtains a detected voltage signal.

[0010] Specifically, the zero-crossing comparator includes an integrated operational amplifier. The zero-crossing comparator compares the signal voltage Ui with the reference voltage zero. If it is higher than the zero voltage, it outputs a high level to the microcontroller AT89C51. When the microcontroller AT89C51 receives the signal, it counts the signal to determine whether there is a real leakage.

[0011] Specifically, the power-off protection module includes a power-off protection circuit, which includes relays J1, J2 and crystal resistors R1, R2, transistor Q1 and diode D1. If a leakage signal is generated, a high level is generated. When the single-chip microcomputer AT89C51 detects the leakage signal, a high level is generated and output to the crystal transistor Q1. After the transistor Q1 amplifies the signal, it can turn on the relay J1 to close, and further turn on the relay J2 to energize, quickly cutting off the power supply of the entire system within 0.1 seconds.

[0012] Specifically, the DC power supply is a 12V power supply.

[0013] Specifically, the alarm circuit includes a manually controlled switch J1. When the switch J1 is closed, the circuit generates leakage, and the indicator light is on; when the switch J1 is open, no leakage signal is generated.

[0014] The beneficial effects of the present invention are as follows: a 12V DC power supply is used to power the system, wherein the leakage detection module applies the electromagnetic induction principle, the changing current generates a magnetic field, and a detected voltage signal can be obtained. The voltage signal is compared with the zero voltage through a zero-crossing comparator. If it is higher than the zero voltage, a high level is output to AT89C51. After receiving the signal, AT89C51 counts the signal to determine whether there is leakage. If leakage is determined, a power-off protection module and an alarm module are started. After determining whether there is leakage, the leakage circuit is powered off. After leakage, a buzzer sounds an alarm to ensure that the current can be quickly cut off to prevent danger and ensure personal safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention;

[0016] Figure 2 It is a schematic diagram of the circuit structure of the present invention;

[0017] Figure 3 It is a structural schematic diagram of a zero-crossing comparator of the present invention;

[0018] Figure 4 It is the alarm circuit diagram of the present invention;

[0019] Figure 5 It is a signal detection diagram of the present invention;

[0020] Figure 6 This is a power-off protection circuit diagram of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] like Figure 1 The power marketing electricity safety detector provided by the present invention includes: a leakage detection module, which uses a 12V DC power supply to power the system, wherein the leakage detection module applies the principle of electromagnetic induction, and the changing current generates a magnetic field to obtain a detected voltage signal. The voltage signal passes through a zero-crossing comparator and is compared with the zero voltage. If it is higher than the zero voltage, a high level is output to AT89C51. When AT89C51 receives the signal, it counts the signal to determine whether there is a real leakage. If it is determined that there is a leakage, the power-off protection module and the alarm module are started.

[0023] Figure 2The circuit structure diagram of the present invention is shown, the negative electrode of the zero-crossing comparator is grounded, and if a leakage signal is generated, a high level is generated, and if the relay X1 is disconnected, the relay X2 is closed; when the power-off protection module receives a high level, the relay X1 is closed and the relay X2 is disconnected, and the purpose of power-off protection is achieved; the switch J1 is manually controlled, and when it is closed, the circuit generates leakage, and the small light bulb lights up; when the switch J1 is disconnected, no leakage signal is generated.

[0024] Figure 3 As shown: As a further improvement, the zero-crossing comparator compares the signal voltage Ui with the reference voltage zero. The circuit is composed of an integrated operational amplifier. Its open-loop voltage amplification factor is very large, and the input bias current and offset voltage are very small. If the ideal situation (Aod = infinity, IBI = 0, Uio = 0) is considered, when the integrated operational amplifier works in an open loop, when Ui>0, Uo is a low level; when Ui<0, Uo is a high level. The high and low level values ​​​​of the integrated operational amplifier output are generally the maximum output positive and negative voltage values ​​​​Uom.

[0025] Figure 4 As shown in the alarm module, when the system leaks electricity, the leakage signal is input into the single-chip microcomputer. After judgment, a high level is generated for the alarm circuit, causing it to sound an alarm. Only when the system eliminates the fault and restarts can it work normally.

[0026] Figure 5 As shown: During the use of the device, the live wire and the neutral wire, that is, the conductors of the output current and the input current, are simultaneously passed through a toroidal magnetic core. We can use this coil as a primary mutual inductance coil to generate a magnetic field according to the changing current. If the system leaks electricity, the leakage secondary coil can output a leakage signal. The current input from the power supply flows through the system of all loads and returns to the branch current at the neutral end of the power supply. When there is no grounding current in the branch, the output current should be equal to the input current, and the secondary coil has no leakage signal output. In other words, if the input current and the output current in the power input line are completely equal, no leakage signal is generated. When the system leaks electricity, assuming that the system has a ground leakage current, the input current and the output current will not be equal at this time, and the composite current is the leakage current. The output leakage degree is proportional to the size of the leakage signal.

[0027] Figure 6 As shown: the power-off protection circuit is composed of relays J1, J2 and crystal resistors R1, R2, transistor Q1, and diode D1. When the single-chip microcomputer detects a leakage signal, a high voltage is generated and output to the crystal transistor Q1. After the transistor Q1 amplifies the signal, it can turn on the relay J1 to close, and further turn on the relay J2 to energize, quickly cutting off the power supply of the entire system within 0.1 seconds.

[0028] The working principle of the present invention is as follows: when the single chip microcomputer detects a leakage signal, a high level is generated and output to the crystal triode Q1. After the triode Q1 amplifies the signal, it can conduct the relay J1 to close, and further conduct the relay J2 to energize, and quickly cut off the power supply of the entire system within 0.1 seconds. In the alarm module, when the system leaks electricity, the leakage signal is input into the single chip microcomputer. After judgment, a high level is generated for the alarm circuit, so that it sounds an alarm. Only when the system eliminates the fault and restarts, can it work normally. The zero-crossing comparator compares the signal voltage Ui with the reference voltage zero. The circuit is composed of an integrated operational amplifier. Its open-loop voltage amplification factor is very large, and the input bias current and offset voltage are very small. If it is considered according to the ideal situation (Aod=infinity, IBI=0, Uio=0), when the integrated operational amplifier works in the open loop, when Ui>0, Uo is a low level, and when Ui<0, Uo is a high level. The high and low level values ​​output by the integrated operational amplifier are generally the maximum output positive and negative voltage values ​​Uom.

[0029] During use of the device provided by the present invention, the live wire and the neutral wire, that is, the conductors of the output current and the input current, are simultaneously passed through a toroidal magnetic core. We can use this coil as a primary mutual inductance coil to generate a magnetic field according to the changing current. If the system has leakage, the leakage secondary coil can output a leakage signal. The current input from the power supply flows through the system with all loads and returns to the branch current at the neutral line end of the power supply. When there is no grounding current in the branch, the output current should be equal to the input current, and the secondary coil has no leakage signal output. In other words, if the input current and the output current in the power input line are completely equal, no leakage signal is generated. When the system has leakage, assuming that the system has a ground leakage current, the input current and the output current at this time will not be equal, and the composite current is the leakage current. The output leakage degree is proportional to the size of the leakage signal.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A power marketing electricity safety detector, which uses a DC power supply to power the system, characterized in that: The invention comprises a leakage detection module for obtaining a detected voltage signal. The leakage detection module is connected with a zero-crossing comparator to compare the voltage signal with the zero voltage. If the voltage is higher than the zero voltage, a high level is output to a single-chip microcomputer AT89C51. After receiving the signal, the single-chip microcomputer AT89C51 counts the signal to determine whether there is leakage. If leakage is determined, a power-off protection module and an alarm module are started.

2. The power marketing electricity safety detector according to claim 1 is characterized in that: The leakage detection module adopts the principle of electromagnetic induction, and the wires of the output current and the input current are simultaneously passed through a ring-shaped magnetic core as a primary mutual inductance coil, and a magnetic field is generated according to the changing current to obtain a detected voltage signal.

3. The power marketing electricity safety detector according to claim 1 is characterized in that: The zero-crossing comparator includes an integrated operational amplifier. The zero-crossing comparator compares the signal voltage Ui with the reference voltage zero. If it is higher than the zero voltage, it outputs a high level to the single-chip microcomputer AT89C51. When the single-chip microcomputer AT89C51 receives the signal, it counts the signal to determine whether there is a real leakage.

4. The power marketing electricity safety detector according to claim 1 is characterized in that: The power-off protection module includes a power-off protection circuit, which includes relays J1, J2 and crystal resistors R1, R2, transistor Q1 and diode D1. If a leakage signal is generated, a high level is generated. When the single-chip microcomputer AT89C51 detects the leakage signal, a high level is generated and output to the crystal transistor Q1. After the transistor Q1 amplifies the signal, it can turn on the relay J1 to close, and further turn on the relay J2 to energize, quickly cutting off the power supply of the entire system within 0.1 seconds.

5. The power marketing electricity safety detector according to claim 1 is characterized in that: The DC power supply uses a 12V power supply.

6. The power marketing electricity safety detector according to claim 1 is characterized in that: The alarm circuit includes a manually controlled switch J1. When the switch J1 is closed, the circuit generates leakage, and the indicator light is on; when the switch J1 is open, no leakage signal is generated.

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