An arc unit

Abstract

This invention provides an arc light unit, comprising a control circuit, a photoelectric conversion circuit, and a potential adjustment circuit. The key feature is the inclusion of a potential comparison circuit. This potential comparison circuit obtains an adjustable potential threshold from the potential adjustment circuit. It also obtains the arc light signal potential from the photoelectric conversion circuit, with each photoelectric conversion circuit corresponding to a potential adjustment circuit. When the arc light signal potential does not meet a comparison condition, the potential comparison circuit sends a suppression signal to the control circuit. When the arc light signal potential meets the comparison condition, the potential comparison circuit sends an arc light signal to the control circuit. The comparison condition is that the arc light signal potential obtained by the potential comparison circuit from the photoelectric conversion circuit is greater than the adjustable potential threshold. The arc light unit provided by this invention sends an arc light signal to the control circuit by determining whether the arc light signal potential meets the comparison condition. This arc light unit can be used to adjust the photosensitivity.

Description

Technical Field

[0001] This invention relates to the field of arc protection technology, and in particular to an arc protection unit. Background Technology

[0002] Arc flash protection systems are used to quickly and safely cut off electric arcs in power systems, protecting operators from injury and reducing property damage. When the arc measurement ports of the main control system in the arc flash protection system are insufficient, or if more tripping logic needs to be set, arc flash units are required. Arc flash units can also save on fiber optic costs. Arc flash units can be placed near the location that needs protection, and only one fiber optic cable is needed to connect one arc flash unit to another current or arc flash unit or the main control system. Summary of the Invention

[0003] This invention provides an arc light unit, which includes a control circuit, a photoelectric conversion circuit, and a potential adjustment circuit. Its distinguishing feature is that it further includes a potential comparison circuit.

[0004] The potential comparison circuit obtains the adjustable potential threshold from the potential adjustment circuit;

[0005] The potential comparison circuit obtains the arc signal potential from the photoelectric conversion circuit, and each photoelectric conversion circuit corresponds to a potential adjustment circuit.

[0006] The potential comparison circuit sends a suppression signal to the control circuit when the arc signal potential does not meet the comparison condition;

[0007] The potential comparison circuit does not send a suppression signal to the control circuit when the arc signal potential reaches the comparison condition;

[0008] The comparison condition is that the arc signal potential obtained by the potential comparison circuit from the photoelectric conversion circuit is greater than the adjustable potential threshold.

[0009] Furthermore, the arc light unit also includes an arc light signal circuit, which obtains a high level from the photoelectric conversion circuit and sends an arc light signal to the control circuit.

[0010] Furthermore, the arc unit also includes an interlock circuit, which consists of an arc signal circuit and a potential comparison circuit. After the photoelectric conversion circuit obtains the arc signal, it provides a high level to the arc signal circuit to turn it on. The arc signal circuit sends an electrical signal to the control circuit. After the photoelectric conversion circuit obtains the arc signal, it provides a low level to the potential comparison circuit to lock the potential comparison circuit. When the photoelectric conversion circuit does not obtain the arc signal, the potential comparison circuit turns on and outputs a high potential to the arc signal circuit to lock the arc signal circuit.

[0011] Preferably, the arc signal circuit includes a transistor Q1.

[0012] Furthermore, the control circuit includes an inverter U11A, a NAND gate, and a chip, while the potential comparison circuit includes a transistor Q2.

[0013] Furthermore, the photoelectric conversion circuit includes a light receiver, one end of which is connected to the base of transistor Q1 and the other end of which is connected to the emitter of transistor Q2. The emitter of transistor Q1 is grounded, and the collector is connected to the inverter U11A and the collector of transistor Q2, respectively.

[0014] Furthermore, the potential adjustment circuit includes resistors R11 and R12, and an adjustable resistor R13. The base of transistor Q2 is connected to the adjustable resistor R13. The signal output from inverter U11A is fed to a NAND gate, which transmits the signal to the chip. The two ends of R11 are connected to the voltage divider resistor R1 and the adjustable resistor R13, respectively. The voltage divider resistor R1 is also connected to the optical receiver. One end of R12 is connected to the adjustable resistor R13, and the other end is grounded.

[0015] Furthermore, the arc unit also includes an optical switch, which is connected to the arc detection module and the optical receiver via optical fibers.

[0016] The present invention also provides an arc light protection system including arc light units, the arc light protection system including at least two arc light units, and an optical connector is provided between the arc light units and the arc light detection module.

[0017] The present invention also provides another arc light protection system including arc light units, wherein the arc light protection system includes at least two arc light units, and adjacent arc light units are cascaded in pairs.

[0018] Furthermore, the arc flash protection system also includes a main control system. The main control system monitors the heartbeat packets sent periodically by the arc flash units. When the main control system detects that an arc flash unit has stopped sending heartbeat packets, it determines that the arc flash unit is in a non-working state, turns on the optical switch on the arc flash unit, and the arc flash detection module connected to it sends the detected arc flash signal to the cascaded arc flash unit through the optical switch on the arc flash unit. When the main control system detects that the arc flash unit is sending heartbeat packets periodically, it determines that the arc flash unit is in a working state, turns off the optical switch on the arc flash unit, and the arc flash detection module connected to the arc flash unit sends the arc flash signal to the arc flash unit.

[0019] Furthermore, the arc flash protection system also includes a circuit breaker and a main control system connected to the arc flash unit. The main control system is also connected to a current unit and several arc flash detection modules. The circuit breaker is located between the power supply line and the bus.

[0020] The arc light protection system protects at least one switchgear in a nuclear power plant. The arc light detection module transmits the detected arc light to the main control system, the current unit sends the detected current signal to the main control system, the arc light detection module also transmits the detected arc light to the arc light unit, and the arc light unit converts the arc light into a digital signal and transmits it to the main control system.

[0021] The main control system outputs a trip signal to the circuit breaker based on the received arc or current signal.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides a novel arc light unit that sends an arc light signal to a control circuit by determining whether the arc light signal potential reaches the comparison condition. This arc light unit can be used to adjust the photosensitivity. Attached Figure Description

[0024] Figure 1 This is a circuit diagram of the arc unit in the embodiment;

[0025] Figure 2 This is a structural block diagram of the arc protection system in the embodiment;

[0026] Figure 3 This is a structural block diagram of the arc protection system in the embodiment;

[0027] Figure 4 This is a flowchart of the arc protection system method in the embodiment;

[0028] Figure 5 This is a topology diagram of the arc flash protection system in the embodiment;

[0029] Figure 6 This is a diagram showing the address settings of the DIP switch in the embodiment. Detailed Implementation

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

[0031] In some embodiments, such as Figure 1 As shown, an arc light unit is provided, which includes a control circuit, a photoelectric conversion circuit, and a potential adjustment circuit. Its distinguishing feature is that it further includes a potential comparison circuit.

[0032] The potential comparison circuit obtains the adjustable potential threshold from the potential adjustment circuit;

[0033] The potential comparison circuit obtains the arc signal potential from the photoelectric conversion circuit, and each photoelectric conversion circuit corresponds to a potential adjustment circuit.

[0034] The potential comparison circuit sends a suppression signal to the control circuit when the arc signal potential does not meet the comparison condition;

[0035] The potential comparison circuit does not send a suppression signal to the control circuit when the arc signal potential reaches the comparison condition;

[0036] The comparison condition is that the arc signal potential obtained by the potential comparison circuit from the photoelectric conversion circuit is greater than the adjustable potential threshold.

[0037] like Figure 1 As shown, the method for adjusting the light sensitivity is as follows:

[0038] 1. The emitter potential of Q2 is V. e The base potential of Q2 is V b When V e- V b When the voltage is greater than the on-state potential (typically 0.6V), V e- V b ≥V 导通电位 (Formula 1). Q2 is on.

[0039] 2. The emitter of Q2 is supplied with a high level V by R1 (33k). e The base of Q2 is provided with a low level V by R11 (3k). b When D1 is turned on, a voltage drop V is generated at the emitter potential of Q2. 弧光 Therefore, the arc threshold potential V can be set. 弧光阈值电位 , (V e- V b )-V 弧光阈值电位 =V 导通电位 (Equation 2). It can be seen that V 弧光 Less than or equal to V 弧光阈值电位 At that time, V e- V b The voltage must be greater than the on-state potential, so Q2 will still be conducting. 弧光 Greater than V 弧光阈值电位 At that time, V e- V b It must be less than the on-state potential, so Q2 is cut off.

[0040] 3. When the precision adjustable resistor R13 is adjusted, the base potential of Q2 will increase by ΔV. At this time: V e -(V b +ΔV)-V 弧光阈值电位 =V 导通电位 After rearranging, we get: (V e -V b )-(V 弧光阈值电位 +ΔV)=V 导通电位 (Formula 3)

[0041] It can be seen that V 弧光 Less than or equal to V 弧光阈值电位 When +ΔV, V e-V b The voltage must be greater than the on-state potential, so Q2 will still be conducting. 弧光 Greater than V 弧光阈值电位 When +ΔV, V e- V b The voltage is necessarily lower than the on-state potential, so Q2 is cut off. At this point, it's equivalent to increasing V. 弧光阈值电位 .

[0042] In some embodiments, the arc unit further includes an arc signal circuit, which obtains a high level from the photoelectric conversion circuit and sends an arc signal to the control circuit.

[0043] In some embodiments, the arc unit further includes an interlock circuit, which consists of an arc signal circuit and a potential comparison circuit. After the photoelectric conversion circuit obtains the arc signal, it provides a high level to the arc signal circuit to turn it on. The arc signal circuit sends an electrical signal to the control circuit. After the photoelectric conversion circuit obtains the arc signal, it provides a low level to the potential comparison circuit to lock the potential comparison circuit. When the photoelectric conversion circuit does not obtain the arc signal, the potential comparison circuit turns on and outputs a high potential to the arc signal circuit to lock the arc signal circuit.

[0044] In the interlock circuit, the locking process of Q1 to Q2 is as follows: After D1 receives the arc signal, it provides a high level to the base of Q1, causing Q1 to conduct. At this time, the emitter of Q1 is at a high potential and the collector of Q1 is at a low potential. Therefore, the electrical signal is sent to U11A from the collector of Q1. At the same time, after D1 receives the arc signal, it provides a low level to the emitter of Q2, pulling down the potential of the emitter of Q2, thereby achieving the locking of Q2.

[0045] In the interlock circuit, the locking process of Q2 to Q1 is as follows: When D1 does not receive an arc signal, the emitter of Q2 is at a high potential, the base of Q2 receives the base potential, and Q2 turns on. This causes the collector of Q2 to output a high potential to the collector of Q1. Once the collector of Q1 receives the high potential, Q1 is locked in place.

[0046] Preferably, the arc signal circuit includes a transistor Q1.

[0047] In some embodiments, the control circuit includes an inverter U11A, a NAND gate, and a chip, and the potential comparison circuit includes a transistor Q2.

[0048] In some embodiments, the photoelectric conversion circuit includes a photodetector, one end of which is connected to the base of transistor Q1 and the other end of which is connected to the emitter of transistor Q2. The emitter of transistor Q1 is grounded, and the collector is connected to the inverter U11A and the collector of transistor Q2, respectively.

[0049] The optical receiver uses an SFH250V fiber optic photodiode detector, an inverter of model 74HC14, a NAND gate of model 74hc133, a transistor Q1 of model BC547 (NPN), and a transistor Q2 of model BC557 (PNP). The working principle of the arc signal circuit is as follows: after the optical receiver receives the arc signal, the base of Q1 will obtain a high level and turn on the transistor Q1. The signal is sent from the collector of Q1 to the inverter. The signal output by the inverter U11A is given to the NAND gate and finally transmitted to the chip in the arc unit.

[0050] In some embodiments, the potential adjustment circuit includes resistors R11 and R12, and an adjustable resistor R13. The base of transistor Q2 is connected to the adjustable resistor R13. The signal output from inverter U11A is fed to a NAND gate, which transmits the signal to the chip. The two ends of R11 are connected to voltage divider resistor R1 and adjustable resistor R13, respectively. Voltage divider resistor R1 is also connected to the optical receiver. One end of R12 is connected to adjustable resistor R13, and the other end is grounded.

[0051] The working principle of the potential control circuit is as follows: it consists of resistors R11, R12 and a precision adjustable resistor R13 forming a potential adjustment circuit; wherein, the adjustable resistor R13 is connected to the base of transistor Q2, so that Q2 obtains different base potentials, thereby adjusting the light intensity of the SFH250V light receiver.

[0052] In some embodiments, the arc unit further includes an optical switch, which is connected to the arc detection module and the light receiver via optical fibers.

[0053] Among them, the optical switch models include, but are not limited to, VS / VE18-4N3212.

[0054] like Figure 2 As shown, in some embodiments, an arc light protection system including the above arc light units is provided. The arc light protection system includes at least two arc light units, and adjacent arc light units are cascaded in pairs.

[0055] In some embodiments, the main control system monitors the heartbeat packets sent periodically by the arc light unit. When the main control system detects that an arc light unit has stopped sending heartbeat packets, it determines that the arc light unit is in a non-working state, turns on the optical switch on the arc light unit, and the arc light detection module connected to it sends the detected arc light signal to the cascaded arc light unit through the optical switch on the arc light unit. When the main control system detects that the arc light unit is sending heartbeat packets periodically, it determines that the arc light unit is in a working state, turns off the optical switch on the arc light unit, and the arc light detection module connected to the arc light unit sends the arc light signal to the arc light unit.

[0056] The arc flash protection system works as follows: the main control system monitors the heartbeat packets sent by the arc flash units. If an arc flash unit fails to send a heartbeat packet on time, it can be determined that the arc flash unit has malfunctioned. At this time, the optical switch on the arc flash unit is turned on, and the arc flash detection module connected to the arc flash unit can send the arc flash signal to other arc flash units cascaded with the arc flash unit through the optical switch. This avoids the arc flash signal detected by the arc flash detection module connected to the arc flash unit being unable to be sent to the main control module due to the failure of individual arc flash units, thereby affecting the operation of the entire arc flash protection system.

[0057] In some embodiments, to enable the main control system to quickly and timely identify the arc fault address information of each independent unit, an address is also set in the arc fault unit. The address of the arc fault unit in the same main control system and the address of the current unit in the same system cannot be duplicated. The preset address facilitates the work of operators and remote control, but does not affect the tripping function.

[0058] The address can be set using the internal DIP switch of the arc unit. The address is set according to... Figure 6 As shown in the settings, when the protection system changes the address during operation, the main control system can automatically find the correct address. If the original address cannot be found, the main control system will provide a notification. Similarly, the binary value plus 1 represents the number.

[0059] like Figure 4 As shown, in some embodiments, the arc flash protection system further includes a circuit breaker and a main control system connected to the arc flash unit. The main control system is also connected to a current unit and several arc flash detection modules. The circuit breaker is located between the power supply line and the bus.

[0060] The arc light protection system protects at least one switchgear in a nuclear power plant. The arc light detection module transmits the detected arc light to the main control system, the current unit sends the detected current signal to the main control system, the arc light detection module also transmits the detected arc light to the arc light unit, and the arc light unit converts the arc light into a digital signal and transmits it to the main control system.

[0061] The main control system outputs a trip signal to the circuit breaker based on the received arc or current signal.

[0062] Among them, the optical sensor inputs of the four input buses in the main control system can be programmed according to the output requirements of the main control system. When programming, the optical sensor input of the additional optical unit circuit board of the main control system needs to be considered. The main control system has four fast semiconductor thyristor outputs and six conventional relay outputs, which can be used for alarm, backup trip and internal system fault alarm. All outputs can be programmed.

[0063] When an arc occurs in the switch cabinet, the illuminance is approximately 100,000 lux, and the effective working illuminance is approximately 20,000 lux. The sensitivity of this device to light can be adjusted to a suitable level. Due to the different illuminance in different switch cabinets, adjustments are required. In certain situations, the set value needs to be increased during installation to avoid unnecessary light alarms.

[0064] When the arc flash units are connected to the protection system, their illuminance is first adjusted, and then the sensitivity of the main control system to the illuminance is adjusted according to the trip signal issued. The illuminance of the arc flash units can be adjusted on the potentiometer on their panel. The potentiometer affects all light sensor inputs at the same time. Setting the potentiometer to 30,000 lux can ensure that the system works correctly under normal conditions.

[0065] When connecting the arc flash units to the protection system, their light sensitivity must first be adjusted. This ensures that all units have the same light sensitivity. The arc flash detection units are directly connected to the main control system, and their sensitivity can be adjusted on the main control system panel.

[0066] like Figure 4 As shown, the current alarm port is L3, and the arc alarm port is a section of optical signal input port 1, port 2, and port 3 of the main controller itself.

[0067] like Figure 3 As shown, in some embodiments, an arc light protection system including arc light units is provided. The arc light protection system includes at least two arc light units, and an optical connector is provided between the arc light units and the arc light detection module.

[0068] The optical connectors include, but are not limited to, MPO / PC models. The working principle of the arc flash protection system is as follows: the main control system monitors the heartbeat packets sent by the arc flash units. If an arc flash unit fails to send a heartbeat packet on time, it can be determined that the arc flash unit has failed. At this time, the optical connector on the arc flash unit is adjusted, and the arc flash detection module connected to the arc flash unit can send the arc flash signal to other arc flash units connected to the optical connector through an optical switch. This avoids the arc flash signal detected by the arc flash detection module connected to the arc flash unit being unable to be sent to the main control module due to the failure of individual arc flash units, thereby affecting the operation of the entire arc flash protection system.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An arc light unit, characterized in that, The arc unit includes a control circuit, a photoelectric conversion circuit, and a potential adjustment circuit. It is characterized in that it further includes a potential comparison circuit, which obtains an adjustable potential threshold from the potential adjustment circuit. The potential comparison circuit obtains the arc signal potential from the photoelectric conversion circuit, and each photoelectric conversion circuit corresponds to a potential adjustment circuit. The potential comparison circuit sends a suppression signal to the control circuit when the arc signal potential does not meet the comparison condition; The potential comparison circuit does not send a suppression signal to the control circuit when the arc signal potential reaches the comparison condition; The comparison condition is that the arc signal potential obtained by the potential comparison circuit from the photoelectric conversion circuit is greater than the adjustable potential threshold. The arc light unit also includes an arc light signal circuit, which obtains a high level from the photoelectric conversion circuit and sends an arc light signal to the control circuit; The arc light unit also includes an interlock circuit, which consists of an arc light signal circuit and a potential comparison circuit. After the photoelectric conversion circuit obtains the arc light signal, it provides a high level to the arc light signal circuit to turn it on. The arc light signal circuit sends an electrical signal to the control circuit. After the photoelectric conversion circuit obtains the arc light signal, it provides a low level to the potential comparison circuit to lock the potential comparison circuit. When the photoelectric conversion circuit does not obtain the arc light signal, the potential comparison circuit is turned on and outputs a high potential to the arc light signal circuit to lock the arc light signal circuit. The arc signal circuit includes a transistor Q1, the control circuit includes an inverter U11A, a NAND gate and a chip, and the potential comparison circuit includes a transistor Q2.

2. The arc light unit as described in claim 1, characterized in that, The photoelectric conversion circuit includes a light receiver. One end of the light receiver is connected to the base of transistor Q1, and the other end is connected to the emitter of transistor Q2. The emitter of transistor Q1 is grounded, and the collector is connected to the inverter U11A and the collector of transistor Q2, respectively.

3. The arc light unit as described in claim 2, characterized in that, The potential adjustment circuit includes resistors R11 and R12, and an adjustable resistor R13. The base of transistor Q2 is connected to the adjustable resistor R13. The signal output from inverter U11A is fed to a NAND gate, which transmits the signal to the chip. The two ends of R11 are connected to voltage divider resistor R1 and the adjustable resistor R13, respectively. Voltage divider resistor R1 is also connected to the optical receiver. One end of R12 is connected to the adjustable resistor R13, and the other end is grounded.

4. The arc light unit as described in claim 3, characterized in that, The arc light unit also includes an optical switch, which is connected to the arc light detection module and the optical receiver via optical fibers.

5. An arc light protection system comprising the arc light unit of claim 1, characterized in that, The arc light protection system includes at least two arc light units, and an optical connector is provided between the arc light units and the arc light detection module.

6. An arc light protection system comprising the arc light unit of claim 4, characterized in that, The arc light protection system includes at least two arc light units, and adjacent arc light units are cascaded in pairs.

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