Grounding protection unit of comprehensive compensation device

Abstract

The utility model discloses a grounding protection unit of a comprehensive compensation device, which belongs to the technical field of power distribution safety and comprises a power supply circuit used for generating a direct-current working power supply of the grounding protection unit. The rectification circuit is used for carrying out full-wave rectification and amplitude limiting processing on the measured signal; the detection circuit is used for detecting a detected signal; the signal circuit is used for outputting a ground fault control signal; wherein the power circuit is respectively connected with the rectifying circuit and the signal circuit through power lines, and the detection circuit is respectively connected with the rectifying circuit and the signal circuit; by arranging the power supply circuit, the rectification circuit, the detection circuit and the signal circuit, the safety performance of the comprehensive compensation device is further enhanced, the reliability and the stability of the comprehensive compensation device are improved, the potential difference between the neutral line and the ground can be monitored in real time, and a control signal is sent when the potential difference exceeds a safety threshold.

Description

Technical Field

[0001] The utility model belongs to the technical field of power distribution safety, and in particular relates to a grounding protection unit of a comprehensive compensation device. Background Art

[0002] As we all know, in power systems, the voltage difference between the neutral line and the ground line / earth must be strictly controlled within the safety threshold, usually not allowed to exceed 10V. This is because excessive voltage difference may bring a series of safety hazards and operational problems.

[0003] First, it may cause electric shock accidents. When the human body touches the live electrical housing or other conductive parts, it may suffer electric shock, threatening life safety. Secondly, the increase in the neutral line potential will increase the voltage stress on the insulation of electrical equipment, accelerate the aging of the insulation material or even breakdown, and eventually damage the electrical equipment and reduce the reliability of power supply. In addition, excessive potential difference may also cause the metal housing of the electrical equipment to be charged, generate leakage sparks, and become a fire hazard. At the same time, it will interfere with other electrical signals, increase the power loss of the line, and reduce the quality and efficiency of power supply. Finally, the neutral line is an important part of the grounding protection and lightning protection system. Excessive potential difference will seriously affect the grounding and lightning protection effect, and weaken the ability of the power supply system to resist lightning and operational overvoltage.

[0004] The comprehensive compensation device is a kind of electrical equipment, which is mainly used for monitoring and compensating control of voltage and current in power systems. It can monitor various parameters of voltage and current in real time, such as voltage amplitude, current waveform, etc. It also has certain compensation functions, and can adjust and control voltage and current within a certain range to ensure that power quality indicators are within the allowable range.

[0005] In order to further enhance the safety performance of the integrated compensation device and improve its reliability and stability, a grounding protection unit of the integrated compensation device is needed; the grounding protection unit is integrated in the integrated compensation device and is specifically used to monitor the potential difference between the neutral line and the earth in real time. Once the potential difference exceeds the preset safety threshold, the grounding protection unit will send an alarm signal to remind the operation and maintenance personnel to promptly investigate the cause of the fault to improve the safety performance of the power supply system. Utility Model Content

[0006] The purpose of the utility model is to provide a grounding protection unit of an integrated compensation device, further enhance the safety performance of the integrated compensation device, improve its reliability and stability, monitor the potential difference between the neutral line and the earth in real time, and send a control signal when the potential difference exceeds a safety threshold.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A grounding protection unit of a comprehensive compensation device, comprising:

[0009] A power supply circuit for generating a DC working power supply for the ground protection unit;

[0010] A rectifier circuit for full-wave rectification and amplitude limiting of the measured signal;

[0011] A detection circuit for detecting a measured signal and a signal circuit for outputting a control signal of a ground fault; wherein:

[0012] The power supply circuit is connected to the rectifier circuit and the signal circuit respectively through power lines, and the detection circuit is connected to the rectifier circuit and the signal circuit respectively;

[0013] The detection circuit includes chip No. 1 and chip No. 2; the +5V power supply is connected to pin No. 3 of chip No. 2 through resistor No. 16, resistor No. 17, potentiometer, and test ring No. 5 in sequence; test ring No. 3 is connected to pin No. 2 of chip No. 2 through resistor No. 11; test ring No. 3 is connected to the output pin of chip No. 2 through resistor No. 11 and resistor No. 12 in sequence; the output pin of chip No. 2 is connected to pin No. 3 of chip No. 1 through test ring No. 6 and resistor No. 21 in sequence; the +5V power supply is connected to pin No. 2 of chip No. 1 through resistor No. 13; resistor No. 13 is grounded through a parallel circuit of capacitor No. 15 and resistor No. 14; the output pin of chip No. 1 is connected to test ring No. 4.

[0014] Preferably, the power supply circuit includes an AC power supply module and / or a DC power supply module; by setting the AC power supply module and the DC power supply module, the circuit will automatically select and use the DC or AC power supply module according to the different input power types, without the need for judgment by other external components.

[0015] Preferably, the AC power supply module and the DC power supply module share an input socket and a welding position; for different power types, only the module needs to be replaced without affecting other circuits, and the compatibility is good.

[0016] Preferably, the rectifier circuit includes a bridge rectifier circuit, and the bridge rectifier circuit includes four diodes; it is used to perform full-wave rectification on the measured signal, generate a stable DC voltage V1 as the input of the subsequent circuit, and realize input and output isolation.

[0017] Preferably, a gas discharge tube is provided at the signal input end of the rectifier circuit; the gas discharge tube has a very high breakdown voltage. Once the input signal voltage exceeds its breakdown voltage, it will conduct and discharge, limiting the input voltage within a safe range, thereby preventing surge voltage from damaging the rectifier circuit.

[0018] Preferably, the rectifier circuit includes a filter circuit and a filter capacitor; the filter circuit plays a primary filtering role, performs preliminary filtering on the input signal, and removes high-frequency noise components; the filter capacitor plays a secondary filtering role, performs secondary filtering on the signal after the primary filtering, and further removes residual high-frequency noise.

[0019] Preferably, the signal circuit includes a transistor for controlling an optocoupler or a relay; the transistor is turned on and off according to the level signal output by the detection circuit, and drives the optocoupler or relay to output an isolation signal or a dry node signal.

[0020] Preferably, the signal circuit includes an optocoupler for outputting an optocoupler isolation signal and a relay for outputting a relay dry node signal; different types of output devices are provided to meet the requirements of different external circuit interfaces and improve the compatibility and applicability of the system.

[0021] Compared with the prior art, the beneficial effects of the utility model are:

[0022] The utility model provides a grounding protection unit of a comprehensive compensation device, comprising a power supply circuit, a rectifier circuit, a detection circuit and a signal circuit; the safety performance of the comprehensive compensation device is further enhanced, the reliability and stability thereof are improved, the potential difference between the neutral line and the earth is monitored in real time, and a control signal is issued when the potential difference exceeds a safety threshold; a power supply circuit is provided to generate a DC working power supply required by the grounding protection unit; an AC power supply module or a DC power supply module can be selected to adapt to different control power supply types; a rectifier circuit is provided to perform full-wave rectification and amplitude limiting processing on a voltage signal at a signal input end; a detection circuit is provided to realize detection, judgment and output of an input signal; the detection circuit comprises an adjustable potentiometer, a voltage divider circuit and a voltage ratio circuit connected in sequence comparator; the detection circuit is provided with a voltage comparator; the voltage comparator compares the detection signal with a reference level, and outputs a high-level signal if the detection signal is greater than the reference level, otherwise it outputs a low-level signal, thereby realizing a simple and efficient detection function; the input end of the voltage comparator is connected to a voltage divider circuit, and the voltage divider circuit includes a resistor and an adjustable potentiometer; the voltage divider circuit divides the detection signal into a reference level, and the adjustable potentiometer is used to adjust the reference level to realize the setting of different protection thresholds; a signal circuit is also provided, and when the detection circuit outputs a high-level signal, the triode of the detection circuit is in a conducting state, indicating that the neutral line voltage is within a normal range; when the detection circuit outputs a low-level signal, the triode of the detection circuit is in a non-conducting state, indicating that the neutral line voltage is too high. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a circuit diagram of a preferred embodiment of the utility model;

[0024] Figure 2A circuit diagram of a power supply circuit of a preferred embodiment of the utility model;

[0025] Figure 3 A circuit diagram of a rectifier circuit according to a preferred embodiment of the present utility model;

[0026] Figure 4 A circuit diagram of a detection circuit of a preferred embodiment of the utility model;

[0027] Figure 5 The figure is a circuit diagram of a signal circuit according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the utility model shall fall within the scope of protection of the utility model.

[0029] In the description of the invention of the utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of the utility model can be understood according to specific circumstances.

[0030] like Figure 1-Figure 5 As shown:

[0031] First embodiment: A grounding protection unit of a comprehensive compensation device, comprising:

[0032] A power supply circuit for generating a DC working power supply for the ground protection unit;

[0033] A rectifier circuit for full-wave rectification and amplitude limiting of the measured signal;

[0034] A detection circuit for detecting a measured signal and a signal circuit for outputting a control signal of a ground fault; wherein:

[0035] The power supply circuit is connected to the rectifier circuit and the signal circuit respectively through power supply lines, and the detection circuit is connected to the rectifier circuit and the signal circuit respectively.

[0036] Second embodiment: Based on the first embodiment, the power supply circuit includes an AC power supply module and / or a DC power supply module; by setting the AC power supply module and the DC power supply module, the circuit will automatically select and use the DC or AC power supply module according to the different input power types, without the need for other external components to judge. The AC power supply module and the DC power supply module share an input socket and a welding position; for different power types, only the module needs to be replaced without affecting other circuits, and the compatibility is good.

[0037] For details, please refer to Figure 2 Terminal No. 1 XS1 is the control power interface of the grounding protection unit, and adopts a three-core connector. The second pin of the three-core connector is vacant to increase the creepage distance between the first and third pins. Pin 1 of terminal No. 1 XS1 is connected to the N end of power module No. 1 G1 and the Vin end of power module No. 2 G2. Pin 3 of terminal No. 1 XS1 is connected to the L end of power module No. 1 G1 and the GND end of G2 (pins 23 and 24). Power module No. 1 G1 is an isolated power module for single-phase AC to DC conversion, and power module No. 2 G2 is an isolated power module for DC to DC conversion. The +V0 end of power module No. 1 G1 is connected to the +V0 end of power module No. 2 G2, the + end of capacitor No. 1 C1, the + end of capacitor No. 2 C2, one end of capacitor No. 3 C3, and one end of resistor No. 1 R1 in sequence. The 0V end of the power module G1 is connected to the 0V end of the power module G2, the - end of the capacitor C1, the - end of the capacitor C2, the other end of the capacitor C3, the cathode of the diode HL1, the test ring TP1, and the test ring TP2. The other end of the resistor R1 is connected to the anode of the diode HL1. The outputs of the power module G1 and the power module G2 are connected in parallel.

[0038] According to the type of control power supply of the electrical system, if the control power supply is AC, the first power supply module G1 is selected; if the control power supply is DC, the second power supply module G2 is selected. The pads of the first power supply module G1 and the second power supply module G2 are reserved in the same area on the circuit board.

[0039] When the No. 1 power module G1 or the No. 2 power module G2 works normally, the No. 1 diode HL1 emits light, otherwise it does not emit light, thereby judging whether the working power supply of the ground protection unit is normal.

[0040] The third embodiment: On the basis of the first embodiment, the rectifier circuit includes a bridge rectifier circuit, which includes a diode No. 1 VD1, a diode No. 3 VD3, a diode No. 5 VD5 and a diode No. 6 VD6; it is used to perform full-wave rectification on the measured signal to generate a stable DC voltage V1 as the input of the subsequent circuit. A gas discharge tube is provided at the signal input end of the rectifier circuit; the gas discharge tube has a very high breakdown voltage. Once the input signal voltage exceeds its breakdown voltage, it will conduct and discharge, limiting the input voltage within a safe range, playing a protective role in preventing surge voltage from damaging the rectifier circuit. The rectifier circuit includes a filter circuit and a filter capacitor; the filter circuit plays a primary filtering role, performs preliminary filtering on the input signal, and removes high-frequency noise components; the filter capacitor plays a secondary filtering role, performs secondary filtering on the signal after primary filtering, and further removes residual high-frequency noise.

[0041] For details, please refer to Figure 3 , pin 2 of terminal XS2 is left vacant to increase the creepage distance between pins 1 and 3. Pin 1 of terminal XS2 is connected to one end of thermistor RV1, one end of capacitor C5, one end of capacitor C7, the anode of diode VD1, and the cathode of diode VD5 in sequence. Pin 3 of terminal XS2 is connected to one end of gas discharge tube FV1, the other end of capacitor C5, the other end of capacitor C7, the anode of diode VD3, and the cathode of diode VD6 in sequence. The other end of gas discharge tube FV1 is connected to the other end of thermistor RV1. The cathode of diode VD1 is connected to the cathode of diode VD3 and one end of resistor R2. The other end of resistor R2 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of capacitor C8 and one end of resistor R5. The other end of resistor R5 is connected to one end of resistor R9 and the cathode of voltage regulator diode VD4. The anode of the fifth diode VD5 is connected to the anode of the sixth diode VD6, the other end of the eighth capacitor C8, the other end of the ninth resistor R9, and the anode of the voltage-stabilizing diode VD4.

[0042] Terminal No. 2 XS2 is the signal interface of the grounding protection unit. When in use, pin 1 of terminal No. 2 XS2 is connected to the neutral line of the electrical equipment, and pin 3 of terminal No. 2 XS2 is connected to the PE line of the electrical equipment. When the instantaneous AC peak voltage or DC voltage between pin 1 and pin 3 of terminal No. 2 XS2 exceeds the threshold of the gas discharge tube FV1, the gas discharge tube FV1 is turned on to discharge energy to protect the safety of the subsequent circuit. The AC or DC voltage between pin 1 and pin 3 of terminal No. 2 XS2 passes through the filter circuit of capacitor No. 5 C5 and capacitor No. 7 C7, the bridge rectifier circuit composed of diode No. 1 VD1, diode No. 3 VD3, diode No. 5 VD5, and diode No. 6 VD6, the filter capacitor composed of resistor No. 2 R2, resistor No. 3 R3, and capacitor No. 8 C8, and the voltage divider and limiter circuit composed of resistor No. 5 R5, resistor No. 9 R9, and voltage regulator diode VD4, and obtains a voltage signal V1 with a maximum amplitude of the reverse breakdown voltage of voltage regulator diode VD4.

[0043] Connection between power supply circuit and rectifier circuit: Figure 3 The anode of diode VD5 is connected to Figure 2 0V pin of the power module G2.

[0044] Fourth embodiment: Based on the first embodiment, the detection circuit includes a voltage comparator; the voltage comparator compares the detection signal with the reference level, and outputs a high-level signal if the detection signal is greater than the reference level, otherwise it outputs a low-level signal, thereby realizing a simple and efficient detection function. The input end of the voltage comparator is connected to a voltage divider circuit, which includes a voltage divider resistor and an adjustable potentiometer; the voltage divider circuit divides the detection signal into a reference level, and the adjustable potentiometer is used to adjust the reference level to realize the setting of different protection thresholds.

[0045] For details, please refer to Figure 4, the other end of resistor R16 No. 16 is connected to one end of resistor R17 No. 17, the other end of resistor R17 is connected to one end of potentiometer RP1, the other end of potentiometer is connected to one end of resistor R23 No. 23, the other end of capacitor C14 No. 14, the adjustable end of potentiometer RP1, test ring TP5 No. 5, and pin 3 of chip U2 No. 2. The other end of resistor R11 No. 11 is connected to pin 2 of chip U2 No. 2, and one end of resistor R12 No. 12. The other end of resistor R12 No. 12 is connected to pin 7 of chip U2 No. 2, the other end of resistor R19 No. 19, test ring TP6 No. 6, and one end of resistor R21 No. 21. The other end of resistor R21 No. 21 is connected to the other end of capacitor C11 No. 11, the other end of resistor R24 ​​No. 24, and pin 3 of chip U1 No. 1. The other end of resistor R13 No. 13 is connected to the other end of capacitor C15 No. 15, the other end of resistor R14 No. 14, and pin 2 of chip U1 No. 1. Pin 7 of chip No. 1 U1 is connected to the other end of resistor No. 18 R18 and test ring No. 4 TP4.

[0046] See also Figure 4 , the adjustable voltage divider circuit composed of the sixteenth resistor R16, the seventeenth resistor R17, the potentiometer RP1, the twenty-third resistor R23, the twenty-second resistor R22, and the fourteenth capacitor C14 provides a reference level to the pin 3 of the second chip U2. The voltage signal V1 is connected to the pin 2 of the second chip U2 through the eleventh resistor R11. The second chip U2 is a voltage comparator. When the voltage of the pin 2 of the second chip U2 is greater than the voltage of the pin 3, the pin 7 of the second chip U2 is a high level, otherwise the pin 7 of the second chip U2 is a low level. The nineteenth resistor R19 plays a pull-up role so that the output of the second chip U2 can reach a high level. The filter circuit composed of the twenty-first resistor R21 and the eleventh capacitor C11 plays a filtering role. The twenty-fourth resistor R24 ​​is used to release the charge on the eleventh capacitor C11. The thirteenth resistor R13, the fifteenth capacitor R15, and the fourteenth resistor R14 provide a voltage divider and filter circuit to provide a reference voltage to the pin 2 of the first chip U1. When the level of pin 3 of chip U1 is higher than the level of pin 2 of chip U1, pin 7 of chip U1 is at a low level, otherwise it is at a high level. Resistor R18 provides a pull-up level to pin 7 of chip U1 so that it can reach a high level. Pin 7 of chip U1 outputs a voltage signal N_OV.

[0047] Connection of supply current and detection circuit: Refer to Figure 2 and Figure 4 , Figure 4One end of the sixteenth resistor R16, the pin 5 of the second chip U2, the pin 6 of the second chip U2, the pin 8 of the second chip U2, one end of the nineteenth resistor R19, one end of the thirteenth resistor R13, the pin 5 of the first chip U1, the pin 6 of the first chip U1, the pin 8 of the first chip U1, and one end of the eighteenth resistor R18 are connected to Figure 2 The +V0 end of the power module G2 in the middle. One end of the resistor R22, one end of the capacitor C14, pin 1 of the chip U2, pin 4 of the chip U2, one end of the capacitor C10, one end of the capacitor C11, one end of the resistor R24, one end of the capacitor C15, one end of the resistor R14, one end of the capacitor C9, pin 1 of the chip U1, and pin 4 of the chip U1 are connected to Figure 2 The 0V terminal of the medium power module G2.

[0048] Connection between rectifier circuit and detection circuit: Please refer to Figure 3 and Figure 4 , Figure 4 One end of the eleventh resistor R11 and the third test ring TP3 are connected to Figure 3 The cathode of the medium voltage regulator tube VD4 is used to obtain the voltage signal V1.

[0049] Fifth embodiment: Based on the first embodiment, the signal circuit includes a transistor for controlling an optocoupler or a relay; the transistor is turned on and off according to the level signal output by the detection circuit, driving the optocoupler or relay to output an isolation signal or a dry node signal. The signal circuit includes an optocoupler for outputting an optocoupler isolation signal and a relay for outputting a relay dry node signal; different types of output devices are provided to meet the requirements of different external circuit interfaces and improve the compatibility and scope of application of the system.

[0050] For details, please refer to Figure 5, the other end of resistor No. 4 R4 is connected to the primary anode of optocoupler PHT1. The other end of resistor No. 6 R6 is connected to the anode of diode No. 2 HL2. The cathode of diode No. 2 HL2 is connected to the collector of transistor No. 1 V1 and the cathode of the primary of optocoupler PHT1. The other end of resistor No. 7 R7 is connected to the other end of resistor No. 8 R8, the other end of capacitor No. 12 C12 and the base of transistor No. 1 V1. The collector of the secondary side of optocoupler PHT1 is connected to one end of capacitor No. 4 C4, the cathode of diode No. 2 VD2 and pin 2 of terminal No. 3 XS3. The emitter of the secondary side of optocoupler PHT1 is connected to the other end of capacitor No. 4 C4, the anode of diode No. 2 VD2 and pin 1 of terminal No. 3 XS3. The other end of resistor No. 10 R10 is connected to the anode of diode No. 3 HL3. The cathode of diode No. 3 HL3 is connected to the anode of diode No. 7 VD7, pin 2 of relay KA1 and the collector of transistor No. 2 V2. The other end of the 15th resistor R15 is connected to the other end of the 20th resistor R20, the other end of the 13th capacitor C13, and the base of the 2nd diode V2. Pin 3 of the relay KA1 is connected to pin 3 of the 3rd terminal XS3. Pin 4 of the relay KA1 is connected to pin 4 of the 3rd terminal XS3.

[0051] See also Figure 5 When the voltage signal N_OV is at a high level, pin 1 and pin 2 of terminal No. 3 XS3 are conductive, and pin 3 and pin 4 are conductive; when the voltage signal N_OV is at a low level, pin 1 and pin 2 of terminal No. 3 XS3 are not conductive, and pin 3 and pin 4 are not conductive.

[0052] Connection of power circuit and signal circuit: Please refer to Figure 2 and Figure 5 , Figure 2 The +V0 terminal of the second power module G2 is connected to Figure 5 One end of the No. 4 resistor R4, one end of the No. 6 resistor R6, pin 1 of the relay KA1, the cathode of the No. 7 diode VD7, and one end of the No. 10 resistor R10. Figure 2 The 0V terminal of the second power module G2 is connected to Figure 5 One end of resistor No. 8 R8, one end of capacitor No. 12 C12, the emitter of transistor No. 1 V1, one end of resistor No. 20 R20, one end of capacitor No. 13 C13, and the emitter of transistor No. 2 V2.

[0053] Connection between detection circuit and signal circuit: Please refer to Figure 4 and Figure 5 , Figure 4 The No. 4 test ring TP4 is connected to Figure 5 One end of resistor No. 7 R7 and one end of resistor No. 15 R15.

[0054] See also Figure 2-Figure 5When an AC voltage or a DC voltage exceeding a preset value appears between pin 1 and pin 3 of terminal XS2, pin 1 and pin 2 of terminal XS3 are not conducting, and pin 3 and pin 4 are not conducting. Otherwise, pin 1 and pin 2 of terminal XS3 are conducting, and pin 3 and pin 4 are conducting. Thus, the external circuit connected to terminal XS3 can obtain a control signal of whether the neutral line has a voltage exceeding a safe level.

[0055] Working principle:

[0056] The control power (AC or DC) of the external electrical equipment is input through the No. 1 socket XS1 of the power circuit, and then isolated and voltage-regulated by the No. 1 power module G1 or the No. 2 power module G2 to generate the working DC power required by each internal circuit; the working DC power is output to the rectifier circuit, the detection circuit and the signal circuit to provide working power for these three circuits;

[0057] The external voltage enters the rectifier circuit through the No. 2 terminal XS2, and first passes through the gas discharge tube FV1, which is used to quickly conduct when the input voltage is too high, discharge the overvoltage energy to the ground, and play an overvoltage protection role; then it is filtered through the filter circuit composed of the No. 5 capacitor C5 and the No. 7 capacitor C7 to filter out the high-frequency noise in the input signal; it enters the bridge rectifier circuit composed of the No. 1 diode VD1, the No. 3 diode VD3, the No. 5 diode VD5, and the No. 6 diode VD6 for rectification, and the input AC signal is rectified into a DC signal with a pulse waveform; the rectified current is secondary filtered through the filter circuit composed of the No. 2 resistor R2, the No. 3 resistor R3, and the No. 8 capacitor C8, and the pulse waveform after rectification is further filtered to generate a smooth DC signal; then it enters the voltage divider and limiter circuit composed of the No. 5 resistor R5, the No. 9 resistor R9, and the voltage zener diode VD4 for voltage division and limiting, and the voltage signal is limited to a range as the input signal of the detection circuit; finally, a voltage signal V1 with a maximum amplitude limited by the voltage zener diode VD4 is generated as a reference level signal for subsequent detection and comparison.

[0058] The voltage signal V1 is introduced into the pin 2 of the detection circuit chip U2 through the eleventh resistor R11, and the voltage divider circuit composed of the sixteenth resistor R16, the seventeenth resistor R17, the adjustable potentiometer RP1, the twenty-third resistor R23, the twenty-second resistor R22, and the fourteenth capacitor C14 provides a reference level to the pin 3 of the second chip U2; the second chip U2 is a voltage comparator, which compares the voltage signal V1 on the pin 2 with the reference level on the pin 3. When the voltage signal V1 is greater than the reference level, the pin 7 of the second chip U2 outputs a high level signal; otherwise, it outputs a low level signal; the second chip U2 is a voltage comparator, which compares the voltage signal V1 on the pin 2 with the reference level on the pin 3. When the voltage signal V1 is greater than the reference level, the pin 7 of the second chip U2 outputs a high level signal; otherwise, it outputs a low level signal; The high / low level signal output by chip U2 is transmitted to pin 3 of chip No. 1 U1. A voltage divider and filter circuit composed of resistor No. 13, capacitor No. 15, and resistor No. 14 provides a reference voltage to pin 2 of chip No. 1 U1. The level of pin 3 of chip No. 1 U1 is compared with pin 2 to generate a voltage signal N_OV. When U2 outputs a high level signal, the level of pin 3 is higher than that of pin 2, then U1 outputs a low level. When U2 outputs a low level signal, the level of pin 3 is lower than that of pin 2, then U1 outputs a high level. The voltage signal N_OV is output to the detection circuit through test ring No. 4 TP4.

[0059] The voltage signal N_OV enters the base of transistor 1 V1 and transistor 2 V2 through R7 and R15. Transistor 1 V1 and transistor 2 V2 are in a conducting or non-conducting state according to the high or low state of the voltage signal N_OV level. The conducting and non-conducting of transistor 1 V1 and transistor 2 V2 control the conducting and non-conducting of optocoupler PHT1 and relay KA1 respectively. When the voltage signal N_OV level is high, transistor 1 V1 and transistor 2 V2 are in a conducting or non-conducting state. The base voltage is higher than the emitter voltage, at this time, transistor No. 1 V1 and transistor No. 2 V2 are turned on, and the optocoupler PHT1 and relay KA1 are turned on; the conduction state represents that the neutral line voltage is within the normal range; when the voltage signal N_OV level is low, the base voltage of transistor No. 1 V1 and transistor No. 2 V2 is lower than the emitter voltage, at this time, transistor No. 1 V1 and transistor No. 2 V2 are not turned on; the non-conduction state of the optocoupler PHT1 and relay KA1 indicates that the neutral line voltage is too high.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A grounding protection unit of a comprehensive compensation device, It is characterized in that include: A power supply circuit for generating a DC working power supply for the ground protection unit; A rectifier circuit for full-wave rectification and amplitude limiting of the measured signal; A detection circuit for detecting a measured signal and a signal circuit for outputting a control signal of a ground fault; wherein: The power supply circuit is connected to the rectifier circuit and the signal circuit respectively through power lines, and the detection circuit is connected to the rectifier circuit and the signal circuit respectively; The detection circuit includes chip No. 1 and chip No. 2; the +5V power supply is connected to pin No. 3 of chip No. 2 through resistor No. 16, resistor No. 17, potentiometer, and test ring No. 5 in sequence; test ring No. 3 is connected to pin No. 2 of chip No. 2 through resistor No. 11; test ring No. 3 is connected to the output pin of chip No. 2 through resistor No. 11 and resistor No. 12 in sequence; the output pin of chip No. 2 is connected to pin No. 3 of chip No. 1 through test ring No. 6 and resistor No. 21 in sequence; the +5V power supply is connected to pin No. 2 of chip No. 1 through resistor No. 13; resistor No. 13 is grounded through a parallel circuit of capacitor No. 15 and resistor No. 14; the output pin of chip No. 1 is connected to test ring No.

4.

2. The grounding protection unit of the comprehensive compensation device according to claim 1, It is characterized in that The power supply circuit includes an AC power supply module and / or a DC power supply module.

3. The grounding protection unit of the comprehensive compensation device according to claim 2, It is characterized in that The AC power supply module and the DC power supply module share an input socket and a welding position.

4. The grounding protection unit of the comprehensive compensation device according to claim 1, It is characterized in that The rectifier circuit includes a bridge rectifier circuit including four diodes.

5. The grounding protection unit of the comprehensive compensation device according to claim 4, It is characterized in that A gas discharge tube is arranged at the signal input end of the rectifier circuit.

6. The grounding protection unit of the comprehensive compensation device according to claim 4 or 5, It is characterized in that The rectifier circuit includes a filter circuit and a filter capacitor.

7. The grounding protection unit of the comprehensive compensation device according to claim 1, It is characterized in that The signal circuit includes a transistor for controlling an optical coupler or a relay.

8. The grounding protection unit of the comprehensive compensation device according to claim 7, It is characterized in that The signal circuit comprises an optocoupler for outputting an optocoupler isolation signal and a relay for outputting a relay dry node signal.

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