Transformer differential protection signal conversion circuit

Abstract

The present disclosure belongs to the field of nuclear power technology, and particularly relates to a transformer differential protection signal conversion circuit. In the present disclosure, a capacitor is connected in parallel with the coil of the first relay to form a parallel sub-module. One end of the parallel sub-module is grounded, and the other end of the parallel sub-module is connected to the fourth terminal through a first reverse diode; the input end of the first switch is connected to the first power supply through a second reverse diode. The first output end of the first switch is connected between the parallel sub-module and the first reverse diode, and the second output end of the first switch is connected to the third terminal; the input end of the second switch is connected to the first terminal, the first output end of the second switch is connected to the second terminal, and the second output end of the second switch is open; the transformer differential protection signal conversion circuit of the present disclosure converts the captured differential pulse signal into a normally closed contact signal and outputs it externally, so that the fire alarm system can receive the differential protection signal in a timely manner.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and in particular relates to a transformer differential protection signal conversion circuit. Background Art

[0002] The differential protection signal is a transformer leakage protection signal. When the differential protection signal is triggered, the transformer is powered off, thereby playing a protective role to prevent the leakage from worsening and causing accidents such as fire. The differential protection signal is an extremely short contact signal. When the signal is triggered, the transformer power supply will be immediately disconnected, and the differential protection signal will disappear immediately. It usually lasts for about 50ms (milliseconds).

[0003] The fire alarm system connects detectors, modules and other equipment in series through bus communication to form a loop, and the fire alarm controller completes the communication by inspecting the equipment in the loop one by one. In the design of some industrial fields such as nuclear power plants and thermal power plants, the transformer differential protection signal is introduced into the fire alarm system. When the transformer differential protection signal is triggered, it can be used as an early warning of the transformer area fire alarm, and can also participate in the transformer area fire linkage control. However, in the relevant technology, the inspection cycle of the fire alarm system loop is much longer than the millisecond level, and the differential protection signal is highly likely not to be captured by the fire alarm system module when it is triggered. Therefore, how to make the fire alarm system effectively capture the differential protection signal has become an urgent problem to be solved. Summary of the invention

[0004] In order to overcome the problems existing in the related art, a transformer differential protection signal conversion circuit is provided.

[0005] According to one aspect of the present disclosure, there is provided a

[0006] A transformer differential protection signal conversion circuit, the transformer differential protection signal conversion circuit comprising: a first power supply, a first relay, a capacitor, a first reverse diode, a second reverse diode, and a first terminal row, the coil of the first relay is used to control the actions of a first switch and a second switch, and the first terminal row comprises a first terminal, a second terminal, a third terminal, and a fourth terminal;

[0007] The capacitor is connected in parallel with the coil of the first relay to form a parallel submodule, one end of the parallel submodule is grounded, and the other end of the parallel submodule is connected to the fourth terminal through the first reverse diode;

[0008] The input end of the first switch is connected to the first power supply through the second reverse diode, the first output end of the first switch is connected between the parallel submodule and the first reverse diode, and the second output end of the first switch is connected to the third terminal;

[0009] The input end of the second switch is connected to the first terminal, the first output end of the second switch is connected to the second terminal, and the second output end of the second switch is open-circuited;

[0010] When the third terminal and the fourth terminal do not input the transformer differential protection signal of the fire alarm system, the coil of the first relay is de-energized, the input end of the first switch is connected to the second output end of the first switch, and the input end of the second switch is connected to the second output end of the second switch;

[0011] When the third terminal and the fourth terminal input the transformer differential protection signal of the fire alarm system, the capacitor is charged and supplies power to the coil of the first relay. The coil of the first relay is energized, so that the input end of the first switch is connected to the first output end of the first switch, and the input end of the second switch is connected to the first output end of the second switch, so that the first terminal and the second terminal are connected, and a normally closed signal is output to the fire alarm system.

[0012] In a possible implementation, the capacitance of the capacitor is between 0.00001 - 0.00002 farads, and the discharge time of the capacitor is between 30 - 50 milliseconds.

[0013] In a possible implementation, the transformer differential protection signal conversion circuit further includes a second indicator light, and the second indicator light is connected in parallel with the first relay.

[0014] In a possible implementation, the transformer differential protection signal conversion circuit further includes: a second power supply, a second relay, a third switch, and a second terminal block. The second terminal block includes a fifth terminal and a sixth terminal;

[0015] The coil of the second relay is connected between the second power supply and the ground, and the second power supply is used to supply power to the fire alarm system;

[0016] When the second power supply supplies power, the coil of the second relay is energized, and the third switch is closed so that the fifth terminal and the sixth terminal are connected to output a normally closed signal;

[0017] When the second power supply does not supply power, the coil of the second relay is de-energized, and the third switch is opened so that an open circuit is formed between the fifth terminal and the sixth terminal to output a normally open signal.

[0018] In a possible implementation, the transformer differential protection signal conversion circuit further includes a first indicator light, and the first indicator light is connected in parallel with the second relay.

[0019] In a possible implementation, the transformer differential protection signal conversion circuit further includes: a third power supply, a fourth power supply, a normally open switch, a chip, a variable resistor, and a diode;

[0020] The third power supply is connected to the first input terminal of the chip through the normally open switch;

[0021] The fourth power supply is connected to the second input terminal of the chip through the variable resistor;

[0022] The output terminal of the chip is connected to the positive electrode of the diode, and the negative electrode of the diode is connected to one end of the coil of the first relay;

[0023] When the normally open switch is closed, the third power supply inputs a trigger signal to the first input terminal, and the output terminal of the chip outputs a pulse signal, which is used to simulate the transformer differential protection signal, and the pulse width of the pulse signal changes with the resistance value of the variable resistor.

[0024] In a possible implementation, the transformer differential protection signal conversion circuit further includes a second jumper, and the second jumper is connected between the diode and the coil of the first relay.

[0025] In a possible implementation, the transformer differential protection signal conversion circuit further includes a second jumper, and the second jumper is connected between the second power supply and the second relay.

[0026] The beneficial effects of the present disclosure are as follows: Through the circuit structure cooperation of the first power supply, the first relay, the capacitor, the first reverse diode, the second reverse diode, and the first terminal block, the transformer differential protection signal conversion circuit of the present disclosure converts the captured differential pulse signal into a normally closed contact signal and outputs it externally after capturing the differential pulse signal, so that the fire alarm system can receive the differential protection signal in time; In addition, the capacitor is fully charged during the signal capture process and supplies power to the first relay, which can appropriately extend the power-on time of the relay and effectively prevent the phenomenon that the brake is not in place during the power-on control process of the first relay, ensuring the success rate of signal capture; Further, the output circuit of the normally closed signal and the power supply circuit of the first relay are independent, effectively avoiding the situation that an internal loop is formed when the differential signal does not disappear after the differential signal triggers the first switch to close, and increasing the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of a transformer differential protection signal conversion circuit shown according to an exemplary embodiment.

[0028] In the figure:

[0029] U1, the first power supply; U2, the second power supply; U3, the third power supply; U4, the fourth power supply; Relay2, the first relay; Relay1, the second relay; C6, the capacitor; D1, the first reverse diode; D4, the second reverse diode; D6, the diode; J2, the first terminal block; J1, the second terminal block; JP1, the first jumper; JP2, the second jumper; LED1, the first indicator light; LED2, the second indicator light; U2A, the chip; J2-2, the first terminal; J2-3, the second terminal; J2-4, the third terminal; J2-5, the fourth terminal; J2-4, the third terminal; J2-5, the fourth terminal; J1-1, the fifth terminal; J1-5, the sixth terminal; S1, the reset switch; S2, the normally open switch. Detailed implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 It is a schematic diagram of a transformer differential protection signal conversion circuit shown according to an exemplary embodiment. As Figure 1 shown, the transformer differential protection signal conversion circuit includes: the first power supply U1, the first relay Relay2, the capacitor C6, the first reverse diode D1, the second reverse diode D4, and the first terminal block J2. The first relay Relay2 is used to control the operation of the first switch (t1, t2, t3) and the second switch (t4, t5, t6). Among them, the first switch and the second switch can be single-pole double-throw switches. The first terminal block J2 includes the first terminal J2-2, the second terminal J2-3, the third terminal J2-4, and the fourth terminal J2-5;

[0032] The capacitor C6 is connected in parallel with the coil of the first relay Relay2 to form a parallel sub-module. One end of the parallel sub-module is grounded, and the other end of the parallel sub-module is connected to the fourth terminal J2-5 through the first reverse diode D1;

[0033] The input end t1 of the first switch is connected to the first power supply U1 through the second reverse diode D4. The first output end t2 of the first switch is connected between the parallel sub-module and the first reverse diode D1, and the second output end t3 of the first switch is connected to the third terminal J2-4;

[0034] The input end t4 of the second switch is connected to the first terminal J2-2. The first output end t5 of the second switch is connected to the second terminal J2-3, and the second output end J2-3 of the second switch is open;

[0035] The third terminal J2-4 and the fourth terminal J2-5 can be connected to the monitoring module of the fire alarm system. When the transformer differential protection signal is not input by the monitoring module of the fire alarm system, the first relay Relay2 is de-energized. The input end t1 of the first switch is connected to the second output end t3 of the first switch through the gate of the first switch, and the input end t4 of the second switch is connected to the second output end t6 of the second switch through the gate of the second switch.

[0036] When the transformer differential protection signal is input by the monitoring module of the fire alarm system through the third terminal J2-4 and the fourth terminal J2-5, the capacitor C6 is charged and supplies power to the first relay Relay2. The first relay Relay2 is energized, causing the gates of the first switch and the second switch to act, connecting the input end t1 of the first switch to the first output end t2 of the first switch, and connecting the input end t4 of the second switch to the first output end t5 of the second switch. In this way, the first power supply U1 is connected to the first relay Relay2, continuously supplying power to the first relay Relay2, and keeping the input end t4 of the second switch connected to the first output end t5 of the second switch, so that the first terminal and the second terminal are connected, continuously outputting a normally closed signal to the fire alarm system, enabling the fire alarm system to receive the differential protection signal in a timely manner.

[0037] In a possible implementation, the transformer differential protection signal conversion circuit further includes a reset switch S1. The reset switch S1 is a normally closed switch and is connected between the input end t1 of the first switch and the first reverse diode D4. When the input end t1 of the first switch is connected to the first output end t2 of the first switch, disconnecting the reset switch S1 can reset the transformer differential protection signal conversion circuit.

[0038] Through the circuit structure cooperation of the first power supply, the first relay, the capacitor, the first reverse diode, the second reverse diode, and the first terminal block, the transformer differential protection signal conversion circuit of the present disclosure converts the captured differential pulse signal into a normally closed contact signal and outputs it externally after capturing the differential pulse signal, enabling the fire alarm system to receive the differential protection signal in a timely manner. In addition, the capacitor is fully charged during the signal capture process and supplies power to the first relay, which can appropriately extend the energization time of the relay, effectively preventing the phenomenon that the gate is not in place during the energization control process of the first relay, and ensuring the success rate of signal capture. Further, the output circuit of the normally closed signal and the power supply circuit of the first relay are independent in the present disclosure, effectively avoiding the situation where an internal loop is formed when the differential signal does not disappear after the differential signal triggers the first switch to close, increasing the stability of the circuit.

[0039] In a possible implementation, the capacitance of the capacitor ranges from 0.00001 to 0.00002 farads, and the discharge time of the capacitor ranges from 30 to 50 milliseconds. Since the shortest differential signal is 50 ms, the capacitance of the capacitor ranging from 0.00001 to 0.00002 farads ensures that the capacitor is fully charged within 50 ms. In addition, the discharge time of the capacitor is 30 - 50 milliseconds. Since the operating time of the relay is about 20 milliseconds and considering that the relay cannot work when the voltage is too low, the discharge at the end is actually ineffective. Therefore, the discharge duration of the capacitor between 30 and 50 milliseconds fully guarantees the power supply requirement for the relay to complete its operation.

[0040] In a possible implementation, the transformer differential protection signal conversion circuit further includes a first indicator light LED1, and the first indicator light LED1 is connected in parallel with the first relay Relay2. The first indicator light can indicate whether the transformer differential protection signal is input.

[0041] In a possible implementation, the transformer differential protection signal conversion circuit further includes: a second relay Relay1, a third switch, and a second terminal block J1. The second terminal block J1 includes a fifth terminal J1-1 and a sixth terminal J1-5;

[0042] The coil of the second relay Relay1 is connected to the second power supply U2, and the second power supply U2 is used to supply power to the fire alarm system;

[0043] When the second power supply U2 supplies power, the second relay Relay1 is in the energized state. The second switch is closed to connect the fifth terminal and the sixth terminal to output a normally closed signal, and this normally closed signal is used to indicate that the fire alarm system is powered normally.

[0044] When the second power supply U2 does not supply power, the second relay Relay1 is in the de-energized state. The second switch is opened to form an open circuit between the fifth terminal and the sixth terminal to output a normally open signal, and this normally open signal is used to indicate that the fire alarm system has lost power.

[0045] In a possible implementation, the transformer differential protection signal conversion circuit further includes a second indicator light LED2, and the second indicator light LED2 is connected in parallel with the second relay Relay1. The second indicator light can indicate whether the fire alarm system has lost power.

[0046] In a possible implementation, the transformer differential protection signal conversion circuit further includes: a third power supply U3, a fourth power supply U4, a normally open switch, a chip U2A, a variable resistor, and a diode D6; wherein, the variable resistor can be a variable resistor module, and the variable resistor module can include a plurality of resistors and a plurality of DIP switches. Each resistor is connected in series with a DIP switch to form a resistor sub-module, and a plurality of resistor sub-modules are connected in parallel to form a variable resistor module. The total resistance value of the variable resistor module can be set by controlling the switches of each resistor sub-module. In addition, the variable resistor can also be a sliding variable resistor.

[0047] The third power supply U3 is connected to the first input terminal of the chip U2A through the normally open switch, and the fourth power supply U4 is connected to the second input terminal of the chip U2A through the variable resistor;

[0048] The output terminal of the chip U2A is connected to the positive electrode of the diode, and the negative electrode of the diode is connected to the coil of the first relay Relay2;

[0049] When the normally open switch is closed, the power supply inputs a trigger signal to the first input terminal, and the output terminal of the chip U2A outputs a pulse signal. This pulse signal is used to simulate the transformer differential protection signal, and the pulse width of this pulse signal changes with the resistance value of the variable resistor.

[0050] In a possible implementation, the transformer differential protection signal conversion circuit further includes a first jumper JP1, and the first jumper JP1 is connected between the diode and the first relay Relay2. In a possible implementation, the transformer differential protection signal conversion circuit further includes a second jumper JP2, and the second jumper JP2 is connected between the second power supply U2 and the second relay Relay1. In this way, the connection or disconnection of the first jumper and the second jumper can be controlled as needed, so as to select functions such as power failure alarm and / or transformer differential trigger.

[0051] The above has described the embodiments of the present disclosure. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technologies in the market, or to enable other ordinary skill in the art in the technical field to understand the embodiments disclosed herein.

Claims

1. A transformer differential protection signal conversion circuit, characterized in that The transformer differential protection signal conversion circuit includes: a first power supply, a first relay, a capacitor, a first reverse diode, a second reverse diode, and a first terminal block. The coil of the first relay is used to control the operation of a first switch and a second switch. The first terminal block includes a first terminal, a second terminal, a third terminal, and a fourth terminal; The capacitor is connected in parallel with the coil of the first relay to form a parallel sub-module. One end of the parallel sub-module is grounded, and the other end of the parallel sub-module is connected to the fourth terminal through the first reverse diode; The input end of the first switch is connected to the first power supply through the second reverse diode. The first output end of the first switch is connected between the parallel sub-module and the first reverse diode, and the second output end of the first switch is connected to the third terminal; The input end of the second switch is connected to the first terminal. The first output end of the second switch is connected to the second terminal, and the second output end of the second switch is open; When the transformer differential protection signal of the fire alarm system is not input to the third terminal and the fourth terminal, the coil of the first relay is in a de-energized state. The input end of the first switch is connected to the second output end of the first switch, and the input end of the second switch is connected to the second output end of the second switch; When the transformer differential protection signal of the fire alarm system is input to the third terminal and the fourth terminal, the capacitor is charged and supplies power to the coil of the first relay. The coil of the first relay is energized, so that the input end of the first switch is connected to the first output end of the first switch, and the input end of the second switch is connected to the first output end of the second switch, so that the first terminal and the second terminal are connected, and a normally closed signal is output to the fire alarm system.

2. The transformer differential protection signal conversion circuit according to claim 1, wherein The capacitance of the capacitor is between 0.00001 - 0.00002 farads, and the discharge time of the capacitor is between 30 - 50 milliseconds.

3. The transformer differential protection signal conversion circuit according to claim 1, characterized in that, The transformer differential protection signal conversion circuit further includes a second indicator light, which is connected in parallel with the coil of the first relay.

4. The transformer differential protection signal conversion circuit according to claim 1, wherein The transformer differential protection signal conversion circuit further includes: a second power supply, a second relay, a third switch, and a second terminal block. The second terminal block includes a fifth terminal and a sixth terminal; The coil of the second relay is connected between the second power supply and the ground. The second power supply is used to supply power to the fire alarm system; When the second power supply is supplying power, the coil of the second relay is in an energized state. The third switch is closed so that the fifth terminal and the sixth terminal are connected to output a normally closed signal; When the second power supply is not supplying power, the coil of the second relay is in a de-energized state. The third switch is opened so that an open circuit is formed between the fifth terminal and the sixth terminal to output a normally open signal.

5. The transformer differential protection signal conversion circuit according to claim 4, wherein The transformer differential protection signal conversion circuit further includes a first indicator light, which is connected in parallel with the coil of the second relay.

6. The transformer differential protection signal conversion circuit according to claim 1, characterized in that The transformer differential protection signal conversion circuit further includes: a third power supply, a fourth power supply, a normally open switch, a chip, a variable resistor, and a diode; The third power supply is connected to the first input terminal of the chip through the normally open switch; The fourth power supply is connected to the second input terminal of the chip through the variable resistor; The output terminal of the chip is connected to the positive electrode of the diode, and the negative electrode of the diode is connected to one end of the coil of the first relay; When the normally open switch is closed, the third power supply inputs a trigger signal to the first input terminal, and the output terminal of the chip outputs a pulse signal, which is used to simulate the transformer differential protection signal, and the pulse width of the pulse signal changes with the resistance value of the variable resistor.

7. The transformer differential protection signal conversion circuit according to claim 6, wherein The transformer differential protection signal conversion circuit further includes a second jumper wire, which is connected between the diode and the coil of the first relay.

8. The transformer differential protection signal conversion circuit according to claim 4, characterized in that The transformer differential protection signal conversion circuit further includes a first jumper wire, which is connected between the second power supply and the coil of the second relay.

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