CN210835191U - Current leakage detection display alarm circuit for converter - Google Patents
Current leakage detection display alarm circuit for converter Download PDFInfo
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- CN210835191U CN210835191U CN201921394840.5U CN201921394840U CN210835191U CN 210835191 U CN210835191 U CN 210835191U CN 201921394840 U CN201921394840 U CN 201921394840U CN 210835191 U CN210835191 U CN 210835191U
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Abstract
The utility model discloses a converter leakage current detection display alarm circuit, which relates to the technical field of leakage current detection, and is characterized in that leakage current is collected by a leakage current sampling module to obtain leakage current offset voltage, the leakage current offset voltage is input into a display driver through a rectifier module, different light emitting diodes are lightened by the display driver according to the input voltage, quantitative display is carried out, and the abnormal condition of leakage current in a converter main loop is conveniently, quantitatively and in real time; two terminals are led out from the output end of the display driver and connected into the miniature relay for light and heavy fault alarming so as to inform operators on duty in advance, thereby timely analyzing and eliminating abnormal grounding conditions occurring in a main loop and avoiding major faults. The utility model is suitable for an among all kinds of conversion devices because the leakage current phenomenon takes place for unusual reason, and quantitative demonstration and warning when causing conversion device direct current major loop to appear voltage deviation.
Description
Technical Field
The utility model relates to a leakage current detection technical field more specifically indicates a converter leakage current detection shows warning circuit.
Background
The main transmission device of the hot rolling mill in the prior steel industry uses a MELVEC-3000 GTO variable frequency speed control system which is developed by a Mitsubishi motor in Japan and is controlled in a full digital mode. The whole set of system adopts a plurality of advanced technologies in the transmission field, such as full-digital vector control, diamond three-level PWM modulation, high power factor rectifier, and the like. As shown in fig. 1, the leakage current detection circuit is a detection circuit for detecting whether the dc voltages (P voltage and N voltage) are balanced in the dc loop of the main circuit, so as to detect whether the leakage current occurs in the main transmission control device. The inspection objects are mainly whether the ground insulation of the control main loop, the output circuit breaker, the connecting cable, the motor and other components in the variable frequency speed control system is good or not and whether the abnormal condition of the ground exists or not. The leakage detection circuit adopts two grounding sampling resistors (R64P and R64N), a grounding capacitor C64 and a grounding check board A-SAC 02. The grounding detection circuit only carries out qualitative detection and does not carry out quantitative detection. Such an inspection circuit cannot display in time when a slight grounding (leakage) condition occurs. When the voltage on the grounding capacitor (C64) reaches 9V due to serious leakage, a leakage heavy fault signal is sent out, and the upper-level high-voltage switch trips. Thereby causing great shutdown loss and equipment damage and causing great accidents of shutdown and total replacement.
Before the leakage current detection circuit sends out a leakage current fault signal, namely the deviation voltage of the P voltage and the N voltage does not reach the alarm detection value, the leakage current detection circuit cannot quantitatively and previously inform that the leakage phenomenon exists. When a small or small amount of leakage current exists on the main loop, the abnormal grounding condition can not be known in time, and the slight grounding phenomenon which may cause serious faults can not be eliminated in time in the sprouting state.
SUMMERY OF THE UTILITY MODEL
Technical problem to be solved
The utility model aims at providing a deflector leakage current detects and shows warning circuit, gather the leakage current through leakage current sampling module and obtain the electric leakage offset voltage, the electric leakage offset voltage is inputed to the display driver through rectifier module, light different emitting diode according to the size of input voltage by the display driver, carry out quantitative display; two terminals are led out from the output end of the display driver and connected with a miniature relay for light and heavy fault alarm.
(II) technical scheme
The utility model provides a current leakage detection of converter device shows warning circuit, includes rectifier main circuit DC voltage, its characterized in that: the device also comprises a leakage current sampling module, an offset voltage rectifying module, an offset voltage quantitative display module and an alarm output and protection module;
the leakage current sampling module comprises resistors R64N and R64P and a capacitor C64;
the offset voltage rectifying module comprises a rectifying bridge ZLQ, resistors R1 and R2 and a capacitor C1;
the offset voltage quantitative display module comprises a display driver, a power supply E, a resistor R3, a capacitor C3 and nine light-emitting diodes;
the alarm output and protection module comprises micro relays K1 and K2 and an alarm;
the P-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64P, the N-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64N, the other end of the resistor R64P and the other end of the resistor R64N are connected with one end of a capacitor C64, and the other end of the capacitor C64 is grounded;
the two ends of the capacitor C64 are connected with the input end of the rectifier bridge ZLQ, one end of the output end of the rectifier bridge ZLQ is connected with one end of the resistor R1, one end of the resistor R2 and one end of the capacitor C1, the other end of the output end of the rectifier bridge ZLQ is connected with the other end of the resistor R1, the other end of the capacitor C1 and the negative electrode of the power supply E, and the other end of the resistor R2 is connected with the display driver;
the anode of the power supply E is connected with one end of each of the nine light-emitting diodes, and the other end of each of the nine light-emitting diodes is connected with the display driver;
one ends of the micro relays K1 and K2 are connected with the negative electrode of the power supply E, the other ends of the micro relays K1 and K2 are connected with the other ends of the two light-emitting diodes, and auxiliary contacts of the micro relays K1 and K2 are connected with the alarm.
According to an embodiment of the present invention, the display driver is LM 3914.
According to an embodiment of the present invention, pins 2, 4 and 8 of the LM3914 are connected to the negative electrode of the power supply E; pins 3 and 9 of the LM3914 are connected with the anode of a power supply E; pins 6 and 7 of the LM3914 are connected with the negative electrode of the power supply E through a resistor R3; one end of the output end of the rectifier bridge ZLQ is connected with a pin 5 of the LM3914 through a resistor R2; pins 1 and 11-18 of the LM3914 are respectively connected with one ends of nine light-emitting diodes, and the other ends of the nine light-emitting diodes are respectively connected with the anode of a power supply E.
According to an embodiment of the present invention, the pins 1, 11-18 of the LM3914 are respectively connected to the cathodes of the nine leds, and the anodes of the nine leds are respectively connected to the positive electrode of the power supply E.
According to the utility model discloses an embodiment, the one end of micro-relay K1, K2 links to each other with LM 3914's 15, 11 feet respectively, and the other end of micro-relay K1, K2 links to each other with power E negative pole.
(III) advantageous effects
The technical scheme of the utility model is adopted, a converter leakage current detection display alarm circuit, the leakage current is collected through the leakage current sampling module to obtain the leakage current offset voltage, the leakage current offset voltage is input to the display driver through the rectifier module, different light emitting diodes are lightened by the display driver according to the input voltage, the quantitative display is carried out, and the abnormal condition of the leakage current of the converter main loop is conveniently, quantitatively and in real time known; two terminals are led out from the output end of the display driver and connected into the miniature relay for light and heavy fault alarming so as to inform operators on duty in advance, thereby timely analyzing and eliminating abnormal grounding conditions occurring in a main loop and avoiding major faults. The utility model is suitable for an among all kinds of conversion devices because the leakage current phenomenon takes place for unusual reason, and quantitative demonstration and warning when causing conversion device direct current major loop to appear voltage deviation.
Drawings
In the present invention, like reference numerals denote like features throughout, wherein:
fig. 1 is a schematic diagram of a leakage current detection circuit in the prior art.
Fig. 2 is a schematic diagram of the circuit principle of the present invention.
Fig. 3 is a graph showing the input/output signal correspondence of the driver.
Description of reference numerals:
resistance: r1, R2, R3R 64P, R64N; a display driver: LM 3914; capacitance: c1, C2, C64; a rectifier bridge: ZLQ; power supply: e; a light emitting diode: LED1-LED 9; micro relays K1, K2; auxiliary contacts K1a, K2a of the micro relay.
Detailed Description
The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.
Because the insulating bottom plate which is provided with and fixes the main circuit pre-charging rectifier bridge is affected with damp on the main roller main transmission control device (GTO for short) on the hot rolling mill set R2, the alarm is given out when the grounding current is too large for many times. The main drive control device of the hot rolling mill group F6 and F7 rolling mills has large conductivity of cooling pure water but does not reach the specified limit value. When the voltage is long, the ground detection capacitor (C64) has a deviation voltage of about 3V. The plastic pipeline of the pure water is not damaged in time due to discovery. In the main transmission control device of a rolling line of korea, the conductivity of pure water is too high to damage the plastic pipeline, which causes a serious accident of stopping production and completely replacing the plastic pipeline.
Through the analysis and investigation of a leakage current detection device on a direct-current link of a main transmission control device of a hot rolling mill set and a detection circuit (A-SAC02 board), the characteristics of circuit characteristics and action principle are analyzed, and a leakage current detection display alarm circuit of a converter device, which comprises the steps of sampling, rectifying and alarming the offset voltage after electric leakage, is provided.
A leakage current detection display alarm circuit of a converter device comprises a rectifier main circuit direct current voltage, a leakage current sampling module, an offset voltage rectifier module, an offset voltage quantitative display module and an alarm output and protection module; the leakage current sampling module comprises resistors R64N and R64P and a capacitor C64; the offset voltage rectification module comprises a rectification bridge ZLQ, resistors R1 and R2 and a capacitor C1; the offset voltage quantitative display module comprises a display driver, a power supply E, a resistor R3, a capacitor C3 and nine light-emitting diodes; the alarm output and protection module comprises micro relays K1 and K2 and an alarm;
the P-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64P, the N-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64N, the other end of the resistor R64P and the other end of the resistor R64N are connected with one end of a capacitor C64, and the other end of the capacitor C64 is grounded; the two ends of a capacitor C64 are connected with the input end of a rectifier bridge ZLQ, one end of the output end of the rectifier bridge ZLQ is connected with one end of a resistor R1, one end of a resistor R2 and one end of a capacitor C1, the other end of the output end of the rectifier bridge ZLQ is connected with the other end of the resistor R1, the other end of the capacitor C1 and the negative electrode of a power supply E, and the other end of the resistor R2 is connected with a display driver; the anode of the power supply E is connected with one end of the nine light-emitting diodes, and the other end of the nine light-emitting diodes is connected with the display driver; one ends of the micro relays K1 and K2 are connected with the negative electrode of the power supply E, the other ends of the micro relays K1 and K2 are connected with the other ends of the two light-emitting diodes, and auxiliary contacts of the micro relays K1 and K2 are connected with the alarm.
The display driver may be LM 3914. Pins 2, 4 and 8 of the LM3914 are connected with the negative electrode of a power supply E; pins 3 and 9 of the LM3914 are connected with the anode of a power supply E; pins 6 and 7 of the LM3914 are connected with the negative electrode of the power supply E through a resistor R3; one end of the output end of the rectifier bridge ZLQ is connected with a pin 5 of the LM3914 through a resistor R2; pins 1 and 11-18 of the LM3914 are respectively connected with one ends of nine light-emitting diodes, and the other ends of the nine light-emitting diodes are respectively connected with the anode of a power supply E. Pins 1 and 11 to 18 of the LM3914 are respectively connected with the cathodes of the nine light-emitting diodes, and the anodes of the nine light-emitting diodes are respectively connected with the anode of the power supply E. When the ground capacitance of the grounding detection of the current transformation circuit generates offset voltage, the display driver can change the high level and the low level of the output end according to the voltage of the control end so as to light different light emitting diodes, thereby quantitatively displaying the offset voltage.
One ends of the micro relays K1 and K2 are respectively connected with pins 15 and 11 of the LM 3914.
Example (b):
a leakage current detection display alarm circuit of a converter device comprises a rectifier main circuit direct current voltage, a leakage current sampling module, an offset voltage rectifier module, an offset voltage quantitative display module and an alarm output and protection module. The leakage current sampling module detects the leakage current of the direct-current voltage of the main rectifier circuit and outputs leakage offset voltage; the leakage offset voltage is rectified by a rectifier bridge of a rectifier module and then input into a display driver, and different light emitting diodes are lightened by the display driver according to the input voltage to carry out quantitative display; two terminals are led out from the output end of the display driver and connected with a miniature relay for light and heavy fault alarm.
The leakage current sampling module is mainly a sampling circuit formed by a sampling resistor and a grounding capacitor on positive and negative buses in a direct current main loop of the converter device, and takes out offset voltage formed by leakage of the main circuit.
The offset voltage rectifying module rectifies the extracted positive or negative unstable offset voltage into a consistent voltage signal through a rectifying bridge and applies appropriate and simple voltage stabilizing measures.
The quantitative display of the offset voltage is to connect the processed offset voltage signal to the display driver, and the display driver selects LM 3914. When the input signal is increased from small, 10 output terminals (pin 1, pin 18-10) of the LM3914 sequentially become low level, so that the leds connected to these terminals sequentially emit light. To quantitatively display the leakage degree.
The corresponding relationship curve of the input and output signals of the display driver is shown in fig. 3. When the leakage phenomenon exists in the main loop circuit, the offset voltage signal (Ui) is generated in the detection circuit. The more serious the electric leakage phenomenon is, the larger the offset voltage signal is generated, and when the offset voltage reaches 1V, the light-emitting diode LED1 is lightened; when the offset voltage reaches 2V, the LED2 lights up, when the offset voltage reaches 3V, the LED3 lights up, and so on. In addition, when the leakage current offset voltage reaches 5V, the phenomenon of the equipment leakage is a bit serious, the relay K1 loses power, and the auxiliary contact of the relay K1 gives out a leakage light fault pre-alarm, so that an equipment attendant can know the abnormal condition of the equipment leakage in time; when the leakage current offset voltage reaches 9V, the device has serious leakage phenomenon, the relay K2 loses power, and the auxiliary contact of the relay K generates leakage heavy fault and trips. The machine needs to be stopped for inspection, the reason of electric leakage is found, and the grounding point is eliminated. The alarm output and protection function is to transmit the abnormal leakage condition existing in the converter to the monitoring system of the person on duty through the relay auxiliary contact signal in a slight time; and when the serious condition is serious, the upper switch is switched off. The detection voltage values of the light fault signal and the heavy fault signal are respectively 5V and 9V.
The utility model discloses technical scheme implements the back at hot rolling mill group final drive variable frequency speed control system, and the output circuit breaker who takes place is female arranges ground connection, the pure water conductivity abnormal conditions such as exceeding standard and has played in time to show foreknowledge.
The concrete conditions are as follows: (1) occurs on the main drive variable frequency speed control system of the hot rolling mill F3. The LED1 on the ground detection circuit at that time has an abnormal condition of flashing. Then, the main loop is subjected to insulation inspection by using the downtime, water stains (water leakage exists above) on the insulator of the fixed busbar in the output breaker are found through careful inspection, and the leakage detection LED1 lamp is not lighted after the water stains on the insulator are cleaned and dried. (2) Occurs on the F6 and F7 main transmission variable frequency speed control system. The two ground detection circuits are found to be in an abnormal condition that the LED1 and the LED2 are both on and the LED3 is flashing. After a plurality of power failure checks, the phenomenon of electric leakage in the main loop is found because the conductivity of the pure water in the pure water cooling exceeds the standard.
In conclusion, the technical scheme of the utility model is adopted, the leakage current detection of converter device shows warning circuit, acquires the leakage current through leakage current sampling module and obtains the leakage current offset voltage, and the leakage current offset voltage is input to the display driver through the rectifier module, and different light emitting diodes are lighted by the display driver according to the size of the input voltage, and the quantitative display is carried out, so that the abnormal condition of the leakage current of the converter main loop can be conveniently, quantitatively known in real time; two terminals are led out from the output end of the display driver and connected into the miniature relay for light and heavy fault alarming so as to inform operators on duty in advance, thereby timely analyzing and eliminating abnormal grounding conditions occurring in a main loop and avoiding major faults. The utility model is suitable for an among all kinds of conversion devices because the leakage current phenomenon takes place for unusual reason, and quantitative demonstration and warning when causing conversion device direct current major loop to appear voltage deviation.
Claims (5)
1. The utility model provides a current leakage detection of converter device shows warning circuit, includes rectifier main circuit DC voltage, its characterized in that: the device also comprises a leakage current sampling module, an offset voltage rectifying module, an offset voltage quantitative display module and an alarm output and protection module;
the leakage current sampling module comprises resistors R64N and R64P and a capacitor C64;
the offset voltage rectifying module comprises a rectifying bridge ZLQ, resistors R1 and R2 and a capacitor C1;
the offset voltage quantitative display module comprises a display driver, a power supply E, a resistor R3, a capacitor C3 and nine light-emitting diodes;
the alarm output and protection module comprises micro relays K1 and K2 and an alarm;
the P-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64P, the N-side bus of the direct-current voltage of the main rectifier circuit is connected with one end of a resistor R64N, the other end of the resistor R64P and the other end of the resistor R64N are connected with one end of a capacitor C64, and the other end of the capacitor C64 is grounded;
the two ends of the capacitor C64 are connected with the input end of the rectifier bridge ZLQ, one end of the output end of the rectifier bridge ZLQ is connected with one end of the resistor R1, one end of the resistor R2 and one end of the capacitor C1, the other end of the output end of the rectifier bridge ZLQ is connected with the other end of the resistor R1, the other end of the capacitor C1 and the negative electrode of the power supply E, and the other end of the resistor R2 is connected with the display driver;
the anode of the power supply E is connected with one end of each of the nine light-emitting diodes, and the other end of each of the nine light-emitting diodes is connected with the display driver;
one ends of the micro relays K1 and K2 are connected with the negative electrode of the power supply E, the other ends of the micro relays K1 and K2 are connected with the other ends of the two light-emitting diodes, and auxiliary contacts of the micro relays K1 and K2 are connected with the alarm.
2. The inverter leakage current detection display alarm circuit as claimed in claim 1, wherein said display driver is LM 3914.
3. The current-leakage detecting and displaying alarm circuit of current transformer as claimed in claim 2, wherein pins 2, 4 and 8 of LM3914 are connected to negative pole of power supply E; pins 3 and 9 of the LM3914 are connected with the anode of a power supply E; pins 6 and 7 of the LM3914 are connected with the negative electrode of the power supply E through a resistor R3; one end of the output end of the rectifier bridge ZLQ is connected with a pin 5 of the LM3914 through a resistor R2; pins 1 and 11-18 of the LM3914 are respectively connected with one ends of nine light-emitting diodes, and the other ends of the nine light-emitting diodes are respectively connected with the anode of a power supply E.
4. The current leakage detection display alarm circuit of claim 3, wherein pins 1 and 11-18 of LM3914 are respectively connected to the cathodes of nine light emitting diodes, and the anodes of the nine light emitting diodes are respectively connected to the anode of power supply E.
5. The current-leakage detecting and displaying alarm circuit of current transformer as claimed in claim 4, wherein one end of said micro relays K1, K2 is connected to pins 15, 11 of LM3914, respectively, and the other end of micro relays K1, K2 is connected to the negative pole of power supply E.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921394840.5U CN210835191U (en) | 2019-08-26 | 2019-08-26 | Current leakage detection display alarm circuit for converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921394840.5U CN210835191U (en) | 2019-08-26 | 2019-08-26 | Current leakage detection display alarm circuit for converter |
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| Publication Number | Publication Date |
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| CN210835191U true CN210835191U (en) | 2020-06-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201921394840.5U Active CN210835191U (en) | 2019-08-26 | 2019-08-26 | Current leakage detection display alarm circuit for converter |
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| CN (1) | CN210835191U (en) |
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- 2019-08-26 CN CN201921394840.5U patent/CN210835191U/en active Active
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