Under-voltage supervision circuit

A technology for monitoring circuits and voltage dividing resistors, applied in circuit devices, protection for undervoltage or no voltage response, emergency protection circuit devices, etc., can solve the problems of complex structure of undervoltage monitoring circuits and poor monitoring effects, etc. Achieve the effects of accurate monitoring prompt results, simple structure, and convenient operation

Inactive Publication Date: 2011-10-19
XJ ELECTRIC +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide an undervoltage monitoring circuit to solve the problems of complex structure and poor monitoring effect of the existing undervoltage monitoring circuit

Method used

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Examples

Experimental program
Comparison scheme
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Embodiment 1

[0020] figure 1 It is a single-phase power supply monitoring circuit diagram of the present invention, which includes a sub-rectifier bridge 1, a current limiting resistor (2, 3), a voltage dividing resistor (4, 5), a reference resistor 6, an optocoupler device 7, and contacts driven by a relay coil 14. The freewheeling diode 12 of the relay coil 13, the filter capacitor (8, 9, 11) and the decoupling capacitor 10. The AC power supply to be monitored is connected between the AC nodes of the rectifier bridge, and two branches are connected in parallel between the positive and negative stages of the output terminal of the rectifier bridge. The first branch is a relay branch, and the second is a voltage dividing monitoring branch. An optocoupler device 7 is arranged between the two branches. The monitoring voltage dividing branch and the optocoupler device 7 constitute a monitoring control unit. The current-limiting resistors (2, 3) and the relay coil 13 are connected in series ...

Embodiment 2

[0024] like Figure 4 As shown, the three phase voltages of the AC voltage are respectively connected to the input ends of the rectifier bridges 401, 402, and 403, and the output of each rectifier bridge is connected to a separate monitoring control unit and a relay branch, and the monitoring control unit and the relay branch Same as Embodiment 1. The relay coil 433 of the A phase controls the relay contact 436 to indicate whether the A phase is undervoltage; the B phase relay coil 434 controls the relay contact 437 to indicate whether the B phase is undervoltage; the C phase relay coil 435 controls the relay contact 438, Indicates whether phase C is undervoltage. Similarly, the line voltage of the three-phase AC can also be connected to the input terminal of the rectifier bridge, so as to realize the separate monitoring of the three-phase line voltage.

Embodiment 3

[0026] like figure 2 As shown, the circuit can monitor the voltage loss of the line voltage of the three-phase power supply, and it includes a rectifier bridge (201, 202, 203) for rectifying the AC voltage, three monitoring control units and a relay branch. The three monitoring and control units have the same circuit structure as that of the first embodiment. Each line voltage corresponds to a rectifier bridge (201, 202, 203), the line voltage (Ua-Ub) is added to the rectifier bridge 201, the relay branch is connected to the output end of the rectifier bridge 201, and the relay branch is connected in series with a current-limiting resistor (214, 215) and relay coil 225; three monitoring control units, each corresponding to a line voltage, each monitoring control unit includes an optocoupler device and a voltage division monitoring branch, each voltage division monitoring branch connected in parallel to the output end of the corresponding line voltage rectifier bridge, includ...

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Abstract

The invention relates to an under-voltage supervision circuit which comprises a relay subcircuit, wherein current-limiting resistors and relay coil are connected in series in the relay subcircuit. The under-voltage supervision circuit also comprises a monitoring control unit which comprises an optical coupler device and a voltage divider monitoring subcircuit. The voltage divider monitoring subcircuit and the relay subcircuit are connected in parallel. The voltage divider monitoring subcircuit also comprises voltage divider resistor and reference resistor which are connected in series. The secondary of the optical coupler device and the relay subcircuit are connected in series. The primary of the optical coupler device and the reference resistor are connected in parallel. The under-voltage supervision circuit in the invention has the advantages of accurate prompt result, simple structure and convenient operation. And the production and maintenance cost are effectively reduced.

Description

technical field [0001] The invention relates to the field of electric power system relay protection, in particular to a power supply undervoltage monitoring circuit. Background technique [0002] In the process of power generation, transmission, distribution, and power consumption, it is often necessary to monitor the voltage of the power supply. In multi-phase power supply, power supply monitoring is particularly important. The existing commonly used power monitoring method is to first use the transformer to perform voltage conversion, then sample and digitally process the voltage, and then monitor the abnormal situation of the voltage, or use the voltage divider to add the voltage to be monitored to the relay coil, through the relay contact The opening and closing to judge the undervoltage situation. Of these two methods, the former has problems such as complex structure and high production and maintenance costs, and the latter cannot make the relay operate accurately wit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26H02H3/24H02H3/253
Inventor 马世玺王振华周俊华高传发王彩凤李富生王全海宋一丁张项安张新昌金全仁张克元赵成功郭震任华锋
Owner XJ ELECTRIC
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