CN213125575U - Electronic relay with selectable ground fault protection function - Google Patents
Electronic relay with selectable ground fault protection function Download PDFInfo
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- CN213125575U CN213125575U CN202022145500.8U CN202022145500U CN213125575U CN 213125575 U CN213125575 U CN 213125575U CN 202022145500 U CN202022145500 U CN 202022145500U CN 213125575 U CN213125575 U CN 213125575U
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Abstract
The utility model discloses an electronic relay with selectable ground fault protection function, relating to the field of electronic relays, which also comprises a zero sequence current transformer sleeved on a three-phase power line, thereby being capable of testing the three-phase current vector sum, the zero sequence current transformer is connected to the existing fault detection controller through a zero sequence current detection circuit, a rectifying circuit inside the zero sequence current detection circuit rectifies the signal of the zero sequence current transformer, a comparison circuit compares and outputs the signal of the zero sequence current transformer, thereby the fault detection controller can judge whether the zero sequence current has fault and execute corresponding trigger operation to realize the ground fault protection function, and the electronic relay is also provided with a dial switch connected to the fault detection controller, thereby the ground fault protection function can be selectively opened, different use scenes are met.
Description
Technical Field
The utility model belongs to the technical field of electronic relay and specifically relates to a take electronic relay of selectable earth fault protect function.
Background
In industrial control applications, motor load devices may be subject to a variety of faults, such as overload, three-phase imbalance, phase loss, etc., which if not protected in time, may further degrade the damaged device. Therefore, an electronic relay is usually installed at the upper end of the existing motor load to provide the above protection functions, and the existing electronic relay product is provided with three current transformers for testing respective working currents of three phases, and a fault detection controller is used for comparing the conditions of the three-phase working currents to judge whether three phases are unbalanced, lack of phases or overloaded, so that an execution mechanism can be triggered according to a set program when the fault is detected, and a main circuit is cut off, thereby providing protection. However, in practical applications, it is also desirable to perform ground fault protection sometimes, i.e. to prevent the phase line insulation of the load from being damaged and contacting the surface of the housing, which may cause damage to the motor, and such ground fault protection function is sometimes needed or sometimes not needed and cannot be implemented.
SUMMERY OF THE UTILITY MODEL
The inventor of the present invention provides an electronic relay with selectable ground fault protection function to the above problems and technical requirements, the technical scheme of the utility model as follows:
the electronic relay with the selectable ground fault protection function comprises a fault detection controller, and further comprises a zero sequence current transformer, a zero sequence current detection circuit and a dial switch, wherein the zero sequence current transformer is sleeved on a three-phase power line and is connected with the fault detection controller through the zero sequence current detection circuit, the zero sequence current detection circuit at least comprises a rectification circuit and a comparison circuit, and the dial switch is connected with the fault detection controller.
The further technical scheme is that the zero sequence current detection circuit comprises a rectifier bridge, two alternating current input ends of the rectifier bridge are used as input ends of the zero sequence current detection circuit to be connected with a zero sequence current transformer, a first capacitor is connected between the two alternating current input ends, a first direct current output end of the rectifier bridge is further connected to a second direct current output end through a second capacitor and a third capacitor, a common end of the second capacitor and the third capacitor is connected with a first alternating current input end of the rectifier bridge, a first direct current output end of the rectifier bridge is further connected to a second direct current output end through a fourth capacitor and a fifth capacitor, a common end of the fourth capacitor and the fifth capacitor is connected with a second alternating current input end of the rectifier bridge, a first direct current output end of the rectifier bridge is further respectively connected with a cathode of a voltage stabilizing diode, a first resistor and a sixth capacitor, and an anode of the voltage stabilizing, the other end of the first resistor and the other end of the sixth capacitor are both connected to a second direct current output end of the rectifier bridge; the first direct current output end of the rectifier bridge is connected with the non-inverting input end of the amplifier, the second direct current output end of the rectifier bridge is connected with the inverting input end of the amplifier through a second resistor, the inverting input end of the amplifier is further connected with a working power supply through a third resistor, the output end of the amplifier is connected with the output end of the zero sequence current detection circuit through a fourth resistor and used for being connected with the fault detection controller, and the output end of the zero sequence current detection circuit is grounded through a seventh capacitor.
The further technical scheme is that the second resistor is a variable resistor.
The technical scheme is that the zero sequence current transformer is arranged in a shell frame of the electronic relay and sleeved on a three-phase power line, the zero sequence current detection circuit is arranged in the zero sequence current detection circuit board, the zero sequence current detection circuit board is realized as one side surface of the shell frame of the electronic relay, and the dial switch is arranged on the shell frame of the electronic relay.
The further technical scheme is that the zero sequence current transformer and the zero sequence current detection circuit are arranged in a shell frame of the electronic relay in the thickness direction of the electronic relay, and the widths of the electronic relay before and after the installation of the zero sequence current transformer and the zero sequence current detection circuit are kept unchanged.
The utility model has the beneficial technical effects that:
the application discloses but area selection ground fault protect function's electronic relay, this electronic relay still establishes the zero sequence current transformer on the three-phase power cord including the cover, consequently can test three-phase current vector sum, zero sequence current transformer is connected to current fault detection controller through zero sequence current detection circuit, the inside rectifier circuit of zero sequence current detection circuit rectifies zero sequence current transformer's signal, comparison circuit carries out comparison output to zero sequence current transformer's signal, thereby make the fault detection controller can judge whether zero sequence current is out of order thereby carry out corresponding trigger operation and realize ground fault protect function, and this application still is provided with the dial switch who is connected to the fault detection controller, thereby make the open of ground fault protect function selectivity, satisfy different use scenes.
Drawings
Fig. 1 is a structural diagram of an electronic relay according to the present invention after adding a ground fault protection function.
Fig. 2 is a circuit diagram of a zero sequence current detection circuit in the present application.
Detailed Description
The following describes the embodiments of the present invention with reference to the accompanying drawings.
The application discloses but area optional earth fault protect function's electronic relay, this electronic relay still includes zero sequence current transformer 1, zero sequence current detection circuit and dial switch 2 except including the conventional three current transformer of installing on the three-phase power cord and the fault detection controller that is used for detecting the trouble and triggering the execution structure, and zero sequence current detection circuit lays in zero sequence current detection circuit board 3 in this application. As shown in fig. 1, in the present application, a zero sequence current transformer 1 is disposed in a housing 4 of an electronic relay and is sleeved on a three-phase power line, and a zero sequence current detection circuit board 3 is implemented as one side surface of the housing 4 of the electronic relay. Furthermore, the zero sequence current transformer 1 and the zero sequence current detection circuit board 3 for laying the zero sequence current detection circuit are arranged in the shell frame of the electronic relay in the thickness direction of the electronic relay, so that after the structure of the electronic relay is added on the basis of the existing product, the thickness of the electronic relay is increased, but the width of the electronic relay is kept unchanged, and the installation of the electronic relay is not influenced.
The zero sequence current transformer 1 is sleeved on a three-phase power line, and the zero sequence current transformer 1 is connected with a fault detection controller through a zero sequence current detection circuit. The zero sequence current detection circuit at least comprises a rectifying circuit and a comparison circuit, wherein the rectifying circuit rectifies a signal input by the zero sequence current transformer 1, and the comparison circuit compares and outputs the signal input by the zero sequence current transformer 1. IN the present application, the rectifier circuit is constructed based on the rectifier bridge, the comparison circuit is constructed based on the amplifier, as shown IN fig. 2, the zero sequence current detection circuit includes the rectifier bridge formed by diodes D1, D2, D3 and D4, two ac input terminals IN1 and IN2 of the rectifier bridge are connected to the zero sequence current transformer 1 as the input terminal VIN of the zero sequence current detection circuit, and a first capacitor C1 is connected between the two ac input terminals. The first dc output terminal OUT1 of the rectifier bridge is further connected to the second dc output terminal OUT2 through a second capacitor C2 and a third capacitor C3, and the common terminal of the second capacitor C2 and the third capacitor C3 is connected to the first ac input terminal IN1 of the rectifier bridge. The first dc output terminal OUT1 of the rectifier bridge is further connected to the second dc output terminal OUT2 through a fourth capacitor C4 and a fifth capacitor C5, and a common terminal of the fourth capacitor C4 and the fifth capacitor C5 is connected to the second ac input terminal IN2 of the rectifier bridge. The first direct current output end OUT1 of the rectifier bridge is further connected to the cathode of the zener diode C0, the first resistor R1 and the sixth capacitor C6, respectively, and the anode of the zener diode C0, the other end of the first resistor R1 and the other end of the sixth capacitor C6 are all connected to the second direct current output end OUT2 of the rectifier bridge. The first dc output OUT1 of the rectifier bridge is connected to the non-inverting input of amplifier U1. The amplifier U1 in this application is model LM239 DR. The second direct current output end OUT2 of the rectifier bridge is connected with the inverting input end of the amplifier through a second resistor R2, the inverting input end of the amplifier is further connected with a working power supply VCC through a third resistor R3, the output end of the amplifier is connected with the output end of the zero sequence current detection circuit through a fourth resistor R4 and used for being connected with the fault detection controller, and the output end of the zero sequence current detection circuit is further grounded through a seventh capacitor C7. In the present application, the second resistor R2 is a variable resistor, and one end of the second resistor R2 is connected to the inverting input terminal of the amplifier U1, and the other end is connected to the active terminal of the second resistor R2 and to the second dc output terminal OUT2 of the rectifier.
The zero sequence current transformer 1 is arranged to test the three-phase current vector sum, the three-phase current vector sum can be subjected to alternating current-direct current conversion and various kinds of processing through a zero sequence current detection circuit, and finally, the three-phase current vector sum is compared with a preset threshold value through an amplifier U1 to output a corresponding signal to a fault detection controller so as to detect a fault and trigger an execution structure to realize a zero sequence current detection protection function. And because the resistance value of the second resistor R2 at the inverting input end of the amplifier U1 in the zero-sequence current detection circuit is variable, the predetermined threshold value for comparing with the three-phase current vector sum can be adjusted according to actual needs to adapt to different detection application scenes.
In addition, the dial switch 2 in the application is installed on a shell frame of the electronic relay, for example, the dial switch 2 is installed on the side face of the shell frame, and the dial switch 2 is connected with the fault detection controller and can provide signals corresponding to the current state for the fault detection controller, so that the fault detection controller can select whether to execute zero-sequence current detection protection according to the state of the dial switch 2, and a customer can select whether to need the ground fault protection function by using the dial switch 2, so that the two use scenes that the ground protection function is needed and the ground protection function is not needed are adapted.
What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and scope of the present invention are to be considered as included within the scope of the present invention.
Claims (5)
1. The electronic relay with the selectable ground fault protection function comprises a fault detection controller and is characterized by further comprising a zero sequence current transformer, a zero sequence current detection circuit and a dial switch, wherein the zero sequence current transformer is sleeved on a three-phase power line and connected with the fault detection controller through the zero sequence current detection circuit, the zero sequence current detection circuit at least comprises a rectification circuit and a comparison circuit, and the dial switch is connected with the fault detection controller.
2. The electronic relay according to claim 1, wherein the zero sequence current detection circuit comprises a rectifier bridge, two ac input terminals of the rectifier bridge are connected to the zero sequence current transformer as input terminals of the zero sequence current detection circuit, a first capacitor is connected between the two ac input terminals, a first dc output terminal of the rectifier bridge is further connected to a second dc output terminal through a second capacitor and a third capacitor, a common terminal of the second capacitor and the third capacitor is connected to the first ac input terminal of the rectifier bridge, the first dc output terminal of the rectifier bridge is further connected to the second dc output terminal through a fourth capacitor and a fifth capacitor, a common terminal of the fourth capacitor and the fifth capacitor is connected to the second ac input terminal of the rectifier bridge, the first dc output terminal of the rectifier bridge is further connected to a cathode of a zener diode, a cathode of the rectifier bridge, and a, The anode of the voltage stabilizing diode, the other end of the first resistor and the other end of the sixth capacitor are connected to the second direct current output end of the rectifier bridge; the first direct current output end of the rectifier bridge is connected with the non-inverting input end of the amplifier, the second direct current output end of the rectifier bridge is connected with the inverting input end of the amplifier through a second resistor, the inverting input end of the amplifier is further connected with a working power supply through a third resistor, the output end of the amplifier is connected with the output end of the zero sequence current detection circuit through a fourth resistor and used for being connected with the fault detection controller, and the output end of the zero sequence current detection circuit is grounded through a seventh capacitor.
3. The electronic relay according to claim 2, wherein the second resistor is a variable resistor.
4. The electronic relay according to any one of claims 1 to 3, wherein the zero sequence current transformer is disposed in a housing of the electronic relay and is sleeved on a three-phase power line, the zero sequence current detection circuit is disposed in a zero sequence current detection circuit board, and the zero sequence current detection circuit board is implemented as one side surface of the housing of the electronic relay, and the dial switch is mounted on the housing of the electronic relay.
5. The electronic relay according to claim 4, wherein the zero sequence current transformer and the zero sequence current detection circuit are provided in a housing of the electronic relay in a thickness direction of the electronic relay, and a width of the electronic relay is kept constant before and after installation of the zero sequence current transformer and the zero sequence current detection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022145500.8U CN213125575U (en) | 2020-09-25 | 2020-09-25 | Electronic relay with selectable ground fault protection function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022145500.8U CN213125575U (en) | 2020-09-25 | 2020-09-25 | Electronic relay with selectable ground fault protection function |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213125575U true CN213125575U (en) | 2021-05-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022145500.8U Active CN213125575U (en) | 2020-09-25 | 2020-09-25 | Electronic relay with selectable ground fault protection function |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213125575U (en) |
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2020
- 2020-09-25 CN CN202022145500.8U patent/CN213125575U/en active Active
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