CN201066783Y - Over-voltage protector for current mutual inductor - Google Patents

Abstract

The utility model relates to an overvoltage protector of a current transformer. The protector is composed as follows: an overvoltage signal detected by a detecting circuit is put into a trigger circuit through a signal insulating circuit; the trigger circuit produces driving signals; one signal controls a light emitting diode LED 1 of an action display circuit to start; an energy-release loop uses controllable silicon to replace a relay at a contact position of the relay which is formerly connected with a secondary terminal to take effect of protection; the other signal drives the controllable silicon of the energy-release loop to be conducted through an output middle circuit to release high-pressure energy, so as to achieve the purpose of protection. Because the response time for conducting the controllable silicon is very short, the protection action time is reduced greatly, and the purpose of effectively protecting the human body safety is achieved.

Description

The current transformer overvoltage protection device

Technical field

The utility model relates to a kind of protector, is meant a kind of current transformer overvoltage protection device especially.This protector operate time of protection postpones little, is widely used in height, the medium-voltage distribution device.

Background technology

At present, existing known current transformer overvoltage protection device structure is made up of testing circuit, protective circuit, display circuit and output circuit.Detection contact is connected with the Current Transformer Secondary terminal; its relay contact that shields is attempted by on the secondary terminal; when Current Transformer Secondary terminal open circuit causes relative high voltage; the LED starter of current transformer overvoltage protection device; expression secondary terminal is opened a way, thereby relay contact closure leads high-pressure energy to discharge the threat of eliminating personnel and equipment simultaneously.But; Current Transformer Secondary terminal open circuit is instantaneous generation when causing relative high voltage; general current transformer overvoltage protection device can not provide the high-pressure energy release channel fast, causes difficulty to protection, causes easily to protect afterwards and do not reach the protection effect.

The operation principle of domestic product of the same type was to detect voltage with pressure-sensitive electricity group in the past, and last executive component is the auxiliary relay of electromagnetic type.As everyone knows, be about 20～30mS the operate time of the auxiliary relay of electromagnetic type.So produce the time that overvoltage plays its secondary circuit short-circuit and should be not less than 20～30mS at least from detecting secondary winding in current transformer.

The highest overvoltage that existing current transformer overvoltage protection device weak point is a current transformer is created in first cycle behind the open circuit, also is in the 20mS.If can not just move and after having produced overvoltage, protect successfully with its inhibition when voltage begins to rise in first cycle after overvoltage produces, be ineffectual; Because caused injury this moment to equipment and personnel.

Summary of the invention

The purpose of this utility model is to avoid above-mentioned weak point of the prior art and product that a kind of current transformer overvoltage protection device is provided.This protector is realized with the electronic circuit technical scheme, no electromagnetic device.

The purpose of this utility model can reach by following measure:

A kind of current transformer overvoltage protection device, its circuit is constructed as follows:

The input of load termination full-wave rectifying circuit, the negativing ending grounding of its full-wave rectifying circuit, its full-wave rectifying circuit anode is through nonlinear resistance RV and capacitor C 1, resistance R 1, the backward diode D1 series circuit ground connection that constitutes in parallel, nonlinear resistance RV and capacitor C 1, resistance R 1, backward diode D1 being connected in series of series circuit that constitutes in parallel a little connects the anode 1 of the diode of photoelectricity isolated tube U2 by resistance R 2, negative terminal 2 ground connection of the diode of photoelectricity isolated tube U2, at the diode of photoelectricity isolated tube U2 just, negative two ends also connect capacitor C 6, the transistor collector of photoelectricity isolated tube U2, shunt capacitance C2 between emitter, the transistor collector of photoelectricity isolated tube U2 connects power supply, and the transistor emitter of photoelectricity isolated tube U2 connects power supply ground through resistance R 4;

3 legs of the emitter contact Power Generation Road microprocessor C4043 of photoelectricity isolated tube U2,8 legs of microprocessor C4043 connect power supply, 5, the 16 leg ground connection of microprocessor C4043, between 8 legs of microprocessor C4043,16 legs and meet capacitor C 4, C5,6,12,14 legs of microprocessor C4043 are by resistance R 5 ground connection and connect capacitor C 3 and be connected to the end of switch AN, and 1 leg of microprocessor C4043 connects the base stage of the T1 of triode through resistance R 10;

The grounded collector of the T1 of triode, two branch roads of backward diode D1 in parallel, resistance R 7 series connection and resistance R 6, LED 1 series connection between two emitters of the T1 of triode, T2, the collector electrode of the T2 of triode is through resistance R 9 ground connection and connect the base stage of the T3 of triode through resistance R 8, the grounded emitter of the T3 of triode, the collector electrode of the T3 of triode connects power supply through relay J, the backward diode of parallel connection;

2 legs of the integrated circuit C3020 of the 2 leg exit intermediate circuits of microprocessor C4043,1 leg of integrated circuit C3020 connects power supply by resistance R 11;

One end of the positive termination load of the controllable silicon T4 of 6 legs, the circuit that releases energy of the integrated circuit C3020 of outlet intermediate circuit, integrated circuit C3020 4 legs connect the control utmost point of controllable silicon T4, the negative terminal of controllable silicon T4 connects the other end of load.

The utility model has following advantage compared to existing technology: whether this protector can open a way at measuring current instrument transformer secondary terminal produces the superpotential while; provide the high-pressure energy release channel to reach the purpose of protection fast; its operate time of protection postpones little, simple in structure.

Description of drawings

The electronic-circuit diagram of Fig. 1 current transformer overvoltage protection device.

Embodiment

Please refer to Fig. 1, produce drive signal through signal isolation circuit to circuits for triggering by the detected overvoltage signal of testing circuit, signal controlling action display circuit, another signal drives the purpose that the loop that releases energy reaches protection through the outlet intermediate circuit.

Release energy the loop at the former relay contact place that shields on the secondary terminal that is connected on, replace relay with controllable silicon.Protector LED 1 starter when Current Transformer Secondary terminal open circuit causes relative high voltage; send triggering signal simultaneously and connect controllable silicon; because the response time of controllable silicon conducting is very little, thereby greatly reduces operate time of protection, reaches the purpose of effective protection personal safety.

Below in conjunction with accompanying drawing this protector is further specified:

When load end produces overvoltage, its signal converts direct current to through full-wave rectifying circuit, its direct current is through nonlinear resistance RV and capacitor C 1, resistance R 1, the backward diode D1 series circuit that constitutes in parallel, in nonlinear resistance RV and capacitor C 1, resistance R 1, backward diode D1 being connected in series of series circuit that constitutes in parallel a little detects forward voltage, its forward voltage signal filters out 3 legs that interference signal is sent to the microprocessor C4043 that triggers the loop through the photoelectricity isolated tube U2 of buffer circuit, arrive when overvoltage after the threshold value of microprocessor C4043, the 1 leg output signal of microprocessor C4043 makes action display circuit LED 1 indicator light light and move the relay J action of display circuit, 2 legs of microprocessor C4043 send actuating signal simultaneously, integrated package C3020 through the outlet intermediate circuit carries out the signal amplification, trigger controllable silicon executive component T4 conducting, discharge high-pressure energy, the peripheral circuit switch AN1 of its microprocessor C4043, resistance R 5, capacitor C 3 is the nulling circuit of microprocessor C4043.

This protector is from detecting high pressure to this process that releases energy, and relevant authoritative department detects through country, and the time is less than in 5ms.

Claims (1)

1. current transformer overvoltage protection device, its circuit is constructed as follows:

The input of load termination full-wave rectifying circuit, the negativing ending grounding of its full-wave rectifying circuit, its full-wave rectifying circuit anode is through nonlinear resistance RV and capacitor C 1, resistance R 1, the backward diode D1 series circuit ground connection that constitutes in parallel, nonlinear resistance RV and capacitor C 1, resistance R 1, backward diode D1 being connected in series of series circuit that constitutes in parallel a little connects the anode 1 of the diode of photoelectricity isolated tube U2 by resistance R 2, negative terminal 2 ground connection of the diode of photoelectricity isolated tube U2, at the diode of photoelectricity isolated tube U2 just, negative two ends also connect capacitor C 6, the transistor collector of photoelectricity isolated tube U2, shunt capacitance C2 between emitter, the transistor collector of photoelectricity isolated tube U2 connects power supply, and the transistor emitter of photoelectricity isolated tube U2 connects power supply ground through resistance R 4;

3 legs of the emitter contact Power Generation Road microprocessor C4043 of photoelectricity isolated tube U2,8 legs of microprocessor C4043 connect power supply, 5, the 16 leg ground connection of microprocessor C4043, between 8 legs of microprocessor C4043,16 legs and meet capacitor C 4, C5,6,12,14 legs of microprocessor C4043 are by resistance R 5 ground connection and connect capacitor C 3 and be connected to the end of switch AN, and 1 leg of microprocessor C4043 connects the base stage of the T1 of triode through resistance R 10;

The grounded collector of the T1 of triode, two branch roads of backward diode D1 in parallel, resistance R 7 series connection and resistance R 6, LED 1 series connection between two emitters of the T1 of triode, T2, the collector electrode of the T2 of triode is through resistance R 9 ground connection and connect the base stage of the T3 of triode through resistance R 8, the grounded emitter of the T3 of triode, the collector electrode of the T3 of triode connects power supply through relay J, the backward diode of parallel connection;

2 legs of the integrated circuit C3020 of the 2 leg exit intermediate circuits of microprocessor C4043,1 leg of integrated circuit C3020 connects power supply by resistance R 11;

It is characterized in that:

One end of the positive termination load of the controllable silicon T4 of 6 legs, the circuit that releases energy of the integrated circuit C3020 of outlet intermediate circuit, integrated circuit C3020 4 legs connect the control utmost point of controllable silicon T4, the negative terminal of controllable silicon T4 connects the other end of load.

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