A three-phase line busbar and outgoing line fault comprehensive processing device

Abstract

The present invention discloses a comprehensive processing device for three-phase line bus and outgoing line faults. A comprehensive switch device is provided on the outgoing line. Thyristors are respectively connected to each phase wire at the lower port of the incoming line switch of the bus. The other ends of the thyristors are connected in parallel with each other and are connected to a common wire. When an interphase short circuit occurs on the bus, the thyristors are controlled to conduct to divert the current at the interphase short circuit fault point; when an interphase short circuit occurs on the outgoing line, the thyristors and the comprehensive switch device cooperate to process the outgoing line fault. This device can comprehensively process bus and outgoing line faults.

Description

Technical Field

[0001] The present invention relates to a device, and more particularly to a comprehensive device for processing three-phase line bus and outgoing line faults. Background Art

[0002] In power distribution, generally, a 10 kV incoming line is introduced into an incoming line switch cabinet and connected to a busbar copper row in the incoming line switch cabinet. An incoming line switch is provided in the incoming line switch cabinet, and then outgoing lines are led out from the busbar copper row through different outgoing line switch cabinets. In actual operation, sometimes phase-to-phase short circuits may occur in the busbar, and phase-to-phase short circuits or single-phase grounding faults may also occur in the outgoing lines. For example, due to an accidental event, a phase-to-phase short circuit occurs in the busbar copper row in the switch cabinet. At this time, a large current discharge will occur along with arc light, and the accumulated high heat may cause an explosion in the switch cabinet, resulting in significant losses. Although the phase-to-phase short circuit will be detected by the detection device and cause the incoming line switch to trip, the mechanical tripping of the incoming line switch takes time, and an explosion accident may still occur during this time. Another example is that a phase-to-phase short circuit in the outgoing line will cause a large-area power outage, and the short circuit point cannot be located in a short time, or a single-phase grounding in the outgoing line will generate step voltage, which also poses a potential danger to personal safety. At present, there is no unified device and method for dealing with busbar short circuit faults and outgoing line short circuit and grounding faults. Summary of the Invention

[0003] The purpose of the present invention is to provide a comprehensive device for processing three-phase line bus and outgoing line faults. After a phase-to-phase short circuit occurs in the busbar and before the incoming line switch trips to cut off the fault, this device diverts the current at the phase-to-phase short circuit fault point, thereby effectively weakening or eliminating the large amount of heat accumulation caused by arc discharge at the fault point and avoiding the occurrence of explosion accidents; when a phase-to-phase short circuit or single-phase grounding occurs in the outgoing line, it can assist in quickly locating and eliminating the fault point.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A comprehensive device for processing three-phase line bus and outgoing line faults, wherein an incoming line switch and several outgoing lines are provided on the busbar, a comprehensive switch device is provided on the outgoing lines, a thyristor is connected to each phase wire at the lower port of the incoming line switch, the other ends of the thyristors are connected in parallel with each other and connected to a common wire. When a phase-to-phase short circuit occurs on the busbar, all the thyristors are controlled to conduct or the thyristor directly connected to the faulty phase wire is controlled to conduct to divert the current at the phase-to-phase short circuit fault point; when a phase-to-phase short circuit occurs in the outgoing line, the comprehensive switch device maintains the conduction of one faulty-phase outgoing line and trips the other faulty-phase outgoing lines, and at the same time makes the outgoing line on the side far from the busbar of a tripped faulty phase conduct with the common wire, and the thyristor directly connected to the live-phase busbar other than the one faulty phase is controlled to conduct intermittently in a cycle or conduct for a fixed duration.

[0006] Preferably, a busbar fault detection device is used to detect busbar faults and control the thyristors to operate. The busbar fault detection device is an arc detection device or a differential detection device. The arc detection device determines the occurrence of an interphase short-circuit fault by detecting the arc at the interphase short-circuit fault point and controls all the thyristors to conduct. The differential detection device determines the occurrence of an interphase short-circuit fault and identifies the faulty phase by the non-conservation of the incoming current of each phase of the busbar and the corresponding phase current of each outgoing line, and then controls the thyristor directly connected to the faulty phase line to conduct to divert the current at the interphase short-circuit fault point.

[0007] Preferably, the busbar fault detection device includes an inlet current detection unit arranged on each phase incoming line of the busbar and an outlet current detection unit corresponding to the same phase on the outgoing line. The current quantity of the inlet current detection unit is converted into an inlet pulse by a voltage-frequency conversion circuit and transmitted to a comparison unit. The current quantity of the outlet current detection unit is converted into an outlet pulse by a voltage-frequency conversion circuit and transmitted to the comparison unit. The comparison unit calculates the difference between the number of inlet pulses and the number of outlet pulses and determines that the phase line is a faulty phase after the difference exceeds a preset value, and simultaneously sends a signal to make the thyristor directly connected to the phase line conduct.

[0008] Preferably, both the inlet current detection unit and the outlet current detection unit include a primary current transformer and a secondary current transformer. A weak current signal is obtained from the secondary current transformer, elevated by a reference voltage elevation circuit, and then sent into the voltage-frequency conversion circuit. The comparison unit includes a counter and an adder / subtractor. The counter calculates the number of pulses, and the adder / subtractor calculates the difference from the number of pulses.

[0009] Preferably, the integrated switch device includes two independent single-pole double-throw switches and a third independent switch for one phase. When the outgoing line is tripped, the single-pole double-throw switch conducts the outgoing line on the side far from the busbar to the common wire.

[0010] Preferably, the integrated switch device includes a three-phase circuit breaker and a short-circuit switch connected in parallel with at least two phases of the three-phase circuit breaker, and also includes a wiring switch that connects the outgoing lines on the side far from the busbar of at least two phases to the common wire respectively.

[0011] Preferably, the integrated switch device includes three independent single-pole single-throw switches and a short-circuit switch connected in parallel with at least two of the single-pole single-throw switches, and also includes a wiring switch that connects the outgoing lines on the side far from the busbar of at least two phases to the common wire.

[0012] Preferably, a resistor is connected in series on the common wire.

[0013] Preferably, the common wire is connected to the ground. When a single-phase ground fault occurs on the outgoing line, the thyristors directly connected to the non-grounded phase bus are controlled to conduct intermittently in a cycle or conduct for a fixed duration.

[0014] In the present invention, after an interphase short-circuit fault occurs on the bus, the thyristors connected in parallel with the bus are immediately turned on, and a loop parallel to the fault point is formed through the thyristors and current is conducted, so that the current at the interphase short-circuit fault point can be diverted, thereby effectively reducing the heat release at the fault point and avoiding the occurrence of explosion. If the bus fault detection device can specifically detect the faulty phase, the thyristors directly connected to the faulty phase can be controlled to conduct, so that the current at the fault point can be diverted more effectively. By using a voltage-frequency conversion circuit to convert the current quantity into pulses and calculating the difference in the number of pulses, the interphase short-circuit fault can be detected faster and the faulty phase can be distinguished, so as to make a quick judgment; for the interphase short-circuit and single-phase ground faults on the outgoing line, a controlled switch capable of detecting the number of current pulses or the current duration can be set on the outgoing line and cooperate with this device for processing: when an interphase short-circuit occurs in two or three phases on the outgoing line, the integrated switch device in the present invention is used to keep one faulty phase conducting, and the other faulty phases are tripped, then the outgoing line on the side far from the bus of the other faulty phase is connected to the common wire, and the thyristors on one live phase other than the conducting phase conduct intermittently in a cycle or conduct for a fixed duration, so that a closed loop can be formed and current pulses or continuous current can be generated, which can be detected by the controlled switch to cut off the fault. For the treatment methods of interphase short-circuit, refer to the invention patent applications 2020114536325 and 2020114536310, and for the treatment methods of single-phase ground, refer to the invention patents 2020114536306 and 2020114514415. Through the reuse of thyristors in the present invention, the interphase short-circuit of the bus is effectively solved, and at the same time, the interphase short-circuit and single-phase ground faults of the outgoing line can be effectively assisted in solving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the present invention;

[0016] Figure 2 is a schematic diagram of an embodiment of the integrated switch device;

[0017] Figure 3 is a schematic diagram of another embodiment of the integrated switch device;

[0018] Figure 4 is a schematic diagram of another embodiment of the integrated switch device;

[0019] Figure 5 is a schematic structural diagram of another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] As Figures 1 to 4 shown, the comprehensive processing device for three-phase line bus and outgoing line faults is installed on bus 1 and each outgoing line 3. An incoming line switch 2 and several outgoing lines 3 are provided on bus 1. On the three-phase lines at the lower port of the incoming line switch 2, a thyristor 4 is respectively connected. The other ends of the three thyristors 4 are connected in parallel with each other. When a phase-to-phase short circuit occurs on bus 1, it will be detected by the fault detection device. The fault detection device then controls all the thyristors 4 to conduct, thus forming a loop in parallel with the fault point and diverting the current at the fault point, reducing the release of heat at the fault point. Or more preferably, the fault detection device can detect the faulty phase, and then controls the thyristor 4 directly connected to the faulty phase line to conduct to divert the current at the phase-to-phase short circuit fault point. At this time, the thyristors 4 of the non-faulty phases do not conduct. Therefore, the manufactured parallel loop is more targeted and the current diversion effect is better.

[0022] In one embodiment, the fault detection device is an arc detection device. The arc detection device detects through arc light and cannot distinguish between the faulty phase and the non-faulty phase. Therefore, after detecting the arc light, it controls all the thyristors 4 to conduct. In another embodiment, the fault detection device is 3 sets of single-phase differential devices. The differential detection device judges the occurrence of a phase-to-phase short circuit fault by the non-conservation of the incoming line current of bus 1 and the currents of each outgoing line and can determine the faulty phase, and then controls the thyristor 4 directly connected to the faulty phase line to conduct to divert the current at the phase-to-phase short circuit fault point. At this time, the current diversion effect is more obvious.

[0023] In a preferred embodiment, the fault detection device includes an inlet current detection unit 5 arranged at the inlet end of bus 1 at the upper port of the incoming line switch 2 and an outlet current detection unit 6 on the outgoing line 3. The current quantity of the inlet current detection unit 5 is converted into an inlet pulse through a voltage-frequency conversion circuit (VFC) and transmitted to a comparison unit 7. The current quantity of the outlet current detection unit 6 is converted into an outlet pulse through a voltage-frequency conversion circuit (VFC) and transmitted to the comparison unit 7. The comparison unit 7 calculates the difference between the number of inlet pulses and the number of outlet pulses and judges that the phase line is the faulty phase after the difference exceeds a preset value. At the same time, it sends a signal to make the thyristor directly connected to this phase line conduct, and sends a signal to trip the incoming line switch 2. This can make the thyristor directly connected to the faulty phase conduct, and send a signal to trip the incoming line switch 2 to cut off the fault, achieving the effect of diverting the current at the fault point before cutting off the fault and reducing the possibility of explosion.

[0024] Both the inlet current detection unit 5 and the outlet current detection unit 6 include a primary current transformer and a secondary current transformer. A weak electric signal is obtained from the secondary current transformer and then sent into the voltage-frequency conversion circuit after being raised by a reference voltage elevation circuit.

[0025] The comparison unit includes a counter and an adder / subtractor. The counter calculates the number of pulses, and the adder / subtractor calculates the difference from the number of pulses.

[0026] The output of the comparison unit is cleared every fixed period to avoid the accumulation of errors exceeding the preset value. In one embodiment, 5 comparison units are set for each phase to calculate the difference between the respective inlet pulse numbers and outlet pulse numbers in parallel, and the output of each comparison unit is cleared every fixed period T (such as 5 milliseconds), and the start times of clearing for different comparison units are separated by T / N = 1 millisecond in sequence (N is the number of comparison units, here N = 5). In this way, the bus fault can be exported in 1 millisecond. When the calculation result of at least one comparison unit exceeds the threshold, a signal is sent to control the conduction of the thyristor. N is a positive integer greater than 1, and preferably 3, 4 or 5, etc. For further detailed implementation content, reference can be made to the utility model patent CN 211183401 U.

[0027] An integrated switch device 8 is installed on each outgoing line 3. The integrated switch device 8 is connected to the common wire 10. The common wire 10 is connected to the parallel ends of three thyristors 4. A resistor 9 can also be connected in series on the common wire for current limiting. When an interphase short circuit occurs on the outgoing line, the integrated switch device 8 can maintain the conduction of a faulty phase of the outgoing line and trip the other faulty phases of the outgoing line. At the same time, the side of the other faulty phase away from the bus (when installing a switch on the outgoing line, the outgoing line at the upper port of the switch is generally close to the bus side, then the outgoing line at the lower port of the switch is the side away from the bus) is connected to the common wire 10. The environment in which this device is used in conjunction is that there are multiple controlled switches installed on the outgoing line, and the controlled switches can cut off the line according to the number of current pulses or the current duration (see the patent applications for invention 2020114536325 and 2020114536310 for details). When a faulty phase of the outgoing line maintains conduction, while the other faulty phases trip, and the side of the other faulty phase away from the bus is connected to the common wire, then the thyristor 4 directly connected to the live-phase bus except the above-mentioned faulty phase (i.e., the phase maintaining conduction) is conducted, and a closed loop can be artificially created by short-circuiting the interphase short-circuit fault point and current can be generated. If the thyristor conducts intermittently in a cycle, discontinuous current pulses are generated. If it conducts for a fixed duration, continuous current is generated. The controlled switch can detect the number of pulses, and the number of pulses triggered by the downstream controlled switch to cut off is less than that of the upstream (closer to the power source) controlled switch to cut off. In this way, the interphase short-circuit fault can be removed. Or when conducting for a fixed duration, the controlled switch detects the current duration, and the current duration triggered by the upstream to cut off is longer than that triggered by the downstream to cut off. In this way, the interphase short-circuit fault point can also be cut off in time.

[0028] In a preferred embodiment ( Figure 2), the integrated switch device includes a phase-to-phase fault short-circuit detection module 801 for detecting the faulty phase, and also includes at least two single-pole double-throw switches 802 and a third switch (the third switch can be either a single-pole double-throw switch or a single-pole single-throw switch), and further includes a current detection unit 803 and a control unit 804. One stationary contact of the two single-pole double-throw switches 802 is connected to the outgoing line on the bus side, the other stationary contact is connected to the common wire 10, and the moving contact is connected to the outgoing line on the side far from the bus. In this way, when the single-pole double-throw switch 802 trips the outgoing line, it can directly conduct the common wire to the outgoing line on the side far from the bus. When the phase-to-phase fault short-circuit detection module 801 detects a phase-to-phase short circuit and the faulty phase (such as an AB short circuit), the control unit 804 maintains the conduction of phase A, trips phase B, and then connects the outgoing line on the side of phase B far from the bus to the common wire. At the same time, the control unit can also issue a conduction command to the thyristor directly connected to one of the phase buses other than phase A (the thyristor connected to phase B or phase C bus). In this way, a closed loop is formed by the thyristor, the bus, the outgoing line of phase A, the phase-to-phase short-circuit fault point, the outgoing line of phase B to the lower port of the outgoing line switch, the common wire, and the power supply. When the thyristor conducts intermittently in a cycle or conducts for a fixed duration, current pulses or continuous current will be generated and captured by the controlled switch arranged on the outgoing line. One controlled switch at the short-circuit fault point trips to cut off the fault, and then the thyristor can be controlled to disconnect.

[0029] The current detection unit 803 is used to detect the current pulses or duration on the outgoing line. When the short-circuit fault point occurs between the integrated switch device 8 and the next controlled switch, when the number of current pulses or duration detected by the current detection unit 803 reaches the preset value, the control unit cuts off the switch on the faulty phase that maintains conduction, thereby eliminating the fault. That is, at this time, the integrated switch device 8 also plays the role of the controlled switch to eliminate the fault.

[0030] In another embodiment of the integrated switch device ( Figure 3 ), the single-pole double-throw switch is replaced with a three-phase circuit breaker 805, and short-circuit switches 806 are arranged on at least two phases. At the same time, connection switches 807 connected to the common wire 10 are arranged on the other two phases that are staggered from at least one phase where the short-circuit switch 806 is arranged. After the three-phase circuit breaker trips, it cuts off the three-phase line, shorts one phase through the short-circuit switch 806 to form "maintaining the conduction of one faulty phase", and then uses the connection switch 807 to connect the side of the other faulty phase far from the bus to the common wire, so as to achieve the function of the aforementioned single-pole double-throw switch.

[0031] In another embodiment of the integrated switch device ( Figure 4), replace the single-pole double-throw switch with three independent single-pole single-throw switches 808, and at the same time, set wiring switches 809 on at least two phases. When an interphase short circuit occurs, maintain one phase conducting and trip the remaining faulty phases, and then use the wiring switch 809 to connect the outgoing line on the side of the other faulty phase far from the bus to the common wire 10.

[0032] Another embodiment is as Figure 5 shown, the common wire 10 is connected to the ground, so that the bus interphase short circuit and the outgoing line interphase short circuit can still be processed in the foregoing manner. And when a single-phase grounding fault occurs on the outgoing line, for example, a single-phase grounding occurs on the A-phase outgoing line. At this time, the thyristors connected to the non-grounded phase such as the B phase (or C phase) can be made to conduct intermittently in a cycle or conduct for a fixed duration. Because the common wire 10 is connected to the ground, a closed loop can be formed between the A-phase outgoing line, the power supply, the B-phase outgoing line, the conducting thyristor 4 and the grounding fault point to generate current pulses or continuous current, and can be detected by the controlled switch. According to the preset cut-off condition of the controlled switch, the nearest controlled switch upstream of the single-phase grounding fault point is cut off to remove the fault. Therefore, when the common wire is grounded, the device can handle the bus interphase short circuit, the outgoing line interphase short circuit and the outgoing line single-phase grounding fault through the multiplexing of thyristors.

[0033] The above embodiments are only several descriptions of the concept and implementation of the present invention, and do not limit it. Under the concept of the present invention, the technical solutions without substantial transformation are still within the protection scope.

Claims

1. A three-phase line bus and outgoing line fault comprehensive processing device, wherein an incoming line switch and several outgoing lines are provided on the bus, Characterized in that, A comprehensive switch device is provided on the outgoing line. A thyristor is connected to each phase line at the lower port of the incoming line switch. The other ends of the thyristors are connected in parallel with each other and connected to a common wire. When a phase-to-phase short circuit occurs on the bus, all the thyristors are controlled to conduct or the thyristor directly connected to the faulty phase line is controlled to conduct to divert the current at the phase-to-phase short circuit fault point; when a phase-to-phase short circuit occurs on the outgoing line, the comprehensive switch device maintains one faulty phase outgoing line to conduct and trips the other faulty phase outgoing lines. At the same time, it makes the outgoing line on the side far from the bus of the tripped faulty phase conduct with the common wire, and the thyristor directly connected to the live-phase bus other than the one faulty phase outgoing line is controlled to conduct intermittently in a cycle or conduct for a fixed duration.

2. The three-phase line bus and outgoing line fault comprehensive processing device according to claim 1, Characterized in that, The bus fault detection device detects the bus fault and controls the action of the thyristor. The bus fault detection device is an arc light detection device or a differential detection device. The arc light detection device judges the occurrence of the phase-to-phase short circuit fault by detecting the arc light at the phase-to-phase short circuit fault point and controls all the thyristors to conduct. The differential detection device judges the occurrence of the phase-to-phase short circuit fault by the non-conservation of the incoming line current of each phase of the bus and the corresponding phase current of each outgoing line and determines the faulty phase, and then controls the thyristor directly connected to the faulty phase line to conduct to divert the current at the phase-to-phase short circuit fault point.

3. The three-phase line bus and outgoing line fault comprehensive processing device according to claim 1, Characterized in that, The bus fault detection device includes an inlet current detection unit arranged on each phase incoming line of the bus and an outlet current detection unit corresponding to the same phase on the outgoing line. The current amount of the inlet current detection unit is converted into an inlet pulse by a voltage-frequency conversion circuit and transmitted to a comparison unit. The current amount of the outlet current detection unit is converted into an outlet pulse by a voltage-frequency conversion circuit and transmitted to the comparison unit. The comparison unit calculates the difference between the number of inlet pulses and the number of outlet pulses and judges that the phase line is a faulty phase after the difference exceeds a preset value, and at the same time sends a signal to make the thyristor directly connected to the phase line conduct.

4. The three-phase line bus and outgoing line fault comprehensive processing device according to claim 3, Characterized in that, Both the inlet current detection unit and the outlet current detection unit include a primary current transformer and a secondary current transformer. A weak current signal is obtained from the secondary current transformer and then raised by a reference voltage raising circuit and then sent into the voltage-frequency conversion circuit. The comparison unit includes a counter and an adder or a subtractor. The counter calculates the number of pulses, and the adder or the subtractor calculates the difference from the number of pulses.

5. The three-phase line bus and outgoing line fault comprehensive processing device according to claim 1, Characterized in that, The comprehensive switch device includes two independent single-pole double-throw switches and a third independent switch. When tripping the outgoing line, the single-pole double-throw switch conducts the outgoing line on the side far from the bus with the common wire.

6. The three-phase line busbar and outgoing line fault comprehensive processing device according to claim 1, characterized in that, the comprehensive switch device includes a three-phase circuit breaker and a short-circuit switch connected in parallel with at least two phases of the three-phase circuit breaker, and further includes a wiring switch for connecting the outgoing lines on the side away from the busbar of at least two phases to the common wire respectively.

7. The three-phase line busbar and outgoing line fault comprehensive processing device according to claim 1, characterized in that, the comprehensive switch device includes three independent single-pole single-throw switches and a short-circuit switch connected in parallel with at least two of the single-pole single-throw switches, and further includes a wiring switch for connecting the outgoing lines on the side away from the busbar of at least two phases to the common wire.

8. The three-phase line busbar and outgoing line fault comprehensive processing device according to claim 1, characterized in that, a resistor is connected in series on the common wire.

9. The three-phase line busbar and outgoing line fault comprehensive processing device according to claim 1, characterized in that, the common wire is connected to the ground, and when a single-phase ground fault occurs on the outgoing line, the thyristors directly connected to the non-grounded phase busbar are controlled to conduct intermittently in a cycle or conduct for a fixed duration.

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