CN216312668U - Dual-power supply system convenient for fault processing - Google Patents

Abstract

The utility model discloses a dual-power supply system convenient for fault processing.A demarcation switch, a partition switch and a section switch are arranged on a three-phase circuit, first switch devices are arranged on the upper port and the lower port of the partition switch, second switch devices are arranged on buses or system neutral points of a first power supply and a second power supply, and the partition switch can be controlled in a split-phase mode so as to cut off any phase or conduct the cut-off phase through an auxiliary switch device. The system can cut off the connection between the interphase short-circuit fault point and the power supplies on the two sides, thereby realizing the coverage of a power supply area to the maximum extent, reducing the adverse effect caused by the interphase short-circuit, being beneficial to reducing the use of a large-current switch and reducing the cost.

Description

Dual-power supply system convenient for fault processing

Technical Field

The utility model relates to the field of power system protection, in particular to a dual-power supply system convenient for fault processing.

Background

At present, when an interphase short circuit occurs on a certain line of a three-phase power supply system, the power supply system has the following processing modes: 1. the reclosing mode is adopted: the first breaker on the line is cut off firstly and then closed, if the first breaker is a transient phase-to-phase short circuit and is eliminated after the first breaker is closed, normal power supply is continued. And if the interphase short-circuit fault still exists after the first breaker is closed, the first breaker is cut off to wait for maintenance. 2. Adopting a time step difference matching method: the method can isolate a fault area, but for a fault with a fault point close to the power supply, a power supply system has long short-circuit current tolerance time and large impact on a power grid. 3. The first breaker is tripped firstly when overcurrent occurs, then the load switches are tripped out without current at the last (other load switches are in a closing state), then the first breaker is superposed, if the fault occurs below the last load switch, the fault can be eliminated, otherwise, the fault current still exists after the first breaker is superposed, at the moment, the first breaker is tripped out again when overcurrent occurs, then the last load switch is tripped out without current, then the first breaker is reclosed again, and if the interphase short circuit occurs between the last load switch and the last load switch, the fault can be eliminated. And by parity of reasoning, the load switch is switched off under no current sequentially upwards until the fault is eliminated. However, during this operation, the power supply system is repeatedly subjected to a large short-circuit current surge, and if the number of times is excessive, damage may be caused to the line, and in addition, the time for removing the line fault is also long. 4. The circuit breakers with fault current tripping capability are configured on the circuit, when a fault occurs, all the circuit breakers are set to be tripped by overcurrent, then the circuit breakers are switched on from the first circuit breaker, and the circuit breakers are tripped by overcurrent, so that the fault is eliminated. If the first breaker is successfully switched on without overcurrent, the overcurrent trip is locked for a period of time, the second breaker is switched on in the period of time, and because the first breaker is subjected to overcurrent locking, the second breaker is subjected to overcurrent tripping, and the fault is removed. If there is no over-current then the next is closed and so on. The scheme requires that each breaker has the capacity of cutting off large current, and has the advantages of high requirement on the breaker, high manufacturing cost, complex logic and longer self-healing time. Therefore, the existing interphase short circuit processing modes have the defects of long time consumption for processing faults, large system impact and high requirement on the capability of switching off large current of a switch.

The utility model discloses a 202022965192.3 provides a can get rid of interphase short circuit's non-effective ground connection power supply system of three-phase, ann has controlled switch, first switch, second switch and third switch in this system, when this system takes place interphase short circuit, cut off the circuit breaker, then first switch is electrified with a trouble looks short circuit, the third switch is with another trouble looks ground connection, can make a ground current after the second switch is closed, thereby utilize controlled switch to detect current information and make a certain controlled switch cut off, thereby the trouble is got rid of to this. The system can quickly locate the interphase short-circuit fault point interval, can automatically, quickly and accurately remove the fault, can well improve the treatment quality of the interphase short-circuit fault, and improves the power supply safety. The utility model patent application 2021106183754 discloses a method for processing interphase short circuit of three-phase power system, setting a partition switch and a section switch on the circuit, the partition switch can cut off large current, the section switch only needs to cut off load current, when interphase short circuit occurs, the section switch is controlled to trip through differential protection, and then the section switch is tripped according to current pulse or current duration, thereby cutting the interphase short circuit fault.

The double-power-supply system is provided with two power supplies, the middle of the double-power-supply system is separated by the demarcation switch, and after one power supply stops transmitting power, the demarcation switch can be closed to use the other power supply to continue supplying power. However, after an inter-phase short-circuit fault occurs, the sectional switch on one side of the fault point is cut off by using the method, so that the short-circuit fault is cut off relative to the power supply on one side, and if the demarcation switch is closed to continue to supply power to the power-off line, the inter-phase short-circuit fault point still exists relative to the power supply on the other side, so that the power supply system is required to have corresponding hardware configuration so as to cut off the fault point again, and how to configure the hardware of the dual-power-supply system becomes a technical problem to be solved in the field.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a dual-power supply system convenient for fault processing, which can cut off the connection between an interphase short-circuit fault point and power supplies on two sides, thereby realizing the coverage of a power supply area to the maximum extent, reducing the adverse effect caused by interphase short-circuit, being beneficial to reducing the use of a large-current switch and reducing the cost.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a dual-power-supply system convenient for fault processing comprises a first power supply and a second power supply, wherein a three-phase line is arranged between the first power supply and the second power supply, a demarcation switch is arranged on the three-phase line, a plurality of partition switches and section switches are further arranged on the three-phase line on two sides of the demarcation switch, and the section switches can cut off the line according to current information; the upper port and the lower port of the partition switch are provided with first switch devices, the first switch devices can connect any phase of two phases or three phases with the ground or a common conductor, second switch devices are arranged on buses or system neutral points of a first power supply and a second power supply, the second switch devices can connect any phase of two phases or three phases of buses or system neutral points with the ground or the common conductor, and the partition switch also has one of the following conditions:

(a) the partition switch can be controlled in a split phase mode so as to cut off any phase;

(b) the partition switch is in three-phase linkage cutting off, an auxiliary switch device is arranged in parallel with the partition switch, and when the partition switch cuts off a three-phase line, the auxiliary switch device can conduct two or any one of three phases of the cut-off three phases.

Preferably, the first switch device is a two-phase independent or three-phase independent switch connected between the upper port or the lower port of the partition switch and the ground or the common conductor, the second switch device is a two-phase independent or three-phase independent switch connected between the bus bar and the ground or the common conductor, or the second switch device is a single-phase switch connected between the system neutral point and the ground or the common conductor.

Preferably, a current limiting resistor is connected in series between the first switching device and the earth or the common conductor, or a current limiting resistor is connected in series between the second switching device and the earth or the common conductor.

Preferably, the second switching device is an electronic power switch.

Preferably, the second switching device is a thyristor.

Preferably, the current limiting resistor is a variable resistor box.

Preferably, a differential protection system is arranged on two adjacent partition switches.

Preferably, the current information is a current pulse or a continuous current, and the section switch can cut off the line according to a preset current pulse number or current duration.

In the scheme, after the interphase short circuit occurs, the power supply system can respectively cut off the section switches on two sides of the fault point, so that the interphase short circuit fault point can be isolated to form the dual-power-supply system, and the power supply of other areas outside the section switches on two sides of the fault point is not affected. The technical scheme distinguishes the partition switch and the section switch, the partition switch can cut off the short-circuited large current, and the section switch can play a role in cutting off the constructed detection loop. The current signal with a smaller current value can be regulated and controlled by arranging the current limiting resistor, namely, the current in the detection loop is controllable current, so that the sectional switch only needs to have the capability of cutting off the small current, the requirement on the cutting performance is greatly reduced, and the performance cost of the switch is further effectively reduced. The system can quickly locate the specific position of the fault point and cut off the fault point by utilizing the action of the section switch aiming at the short-circuit fault point which randomly appears, and has good use effect.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of a dual-power three-phase power system according to the present invention (the first switching device and the second switching device are both three-phase);

FIG. 2 is a schematic structural diagram of another embodiment of a dual-power three-phase power system according to the present invention (the first switching device and the second switching device are both two phases);

FIG. 3 is a schematic structural diagram of another embodiment of a dual-power three-phase power system according to the present invention (a second switching device is connected to a system neutral point);

FIG. 4 is a schematic structural diagram of another embodiment of a dual-power three-phase power system (not connected to the ground but connected to a common conductor) in the present invention;

fig. 5 is a schematic diagram of a variable resistance box structure.

Detailed Description

The utility model will be further illustrated by the following specific embodiments in conjunction with the accompanying drawings:

as shown in fig. 1, the dual-power three-phase power system includes a first power source 1 and a second power source 2, a three-phase power supply line is erected between the two power sources, a boundary switch 3 is arranged in the middle of the power supply line, and the boundary switch 3 is in a disconnected state at any time. The three-phase circuit on both sides of the boundary switch 3 is provided with a plurality of partition switches 4, a protection area is arranged between two adjacent partition switches 4, a differential protection system can be arranged on two adjacent partition switches 4, and when interphase short circuit occurs in the protection area, the differential protection system controls the corresponding electric energy inlet partition switch 4 to trip so as to cut off fault current (a dotted frame in the figure is a certain partition switch and an area thereof capable of cutting off electric energy from the left side or the right side). A plurality of section switches 5 can be arranged in each protection area, and the section switches 5 only need to have the capacity of cutting off load current and do not need to have the capacity of cutting off short-circuit large current, so that the cost is reduced. The section switch 5 can detect current information such as circuit pulse or current duration, and can cut off the line according to preset conditions (see later).

A first switching device 6 is provided at each of the upper and lower ports of the partition switch 4, and the first switching device 6 can connect any one of two or three phases of the upper or lower ports of the partition switch 4 to the ground or a common conductor. For example, in one embodiment, the first switching device 6 is a three-phase switch (fig. 1) with each phase being independently controllable, and is connected between the upper port of the partition switch 4 and the ground, and between the lower port of the partition switch 4 and the ground (if the upper port of the partition switch 4 is connected to a bus, the upper port does not need to be provided with the first switching device), so that the first switching device 6 can connect any phase of the three-phase line to the ground. In another embodiment, only two independent switches may be provided, each connected between a respective one of the two phases of the three-phase line and earth, so that the first switching device 6 can connect either one of the two phases to earth (fig. 2).

A second switching device 7 is provided on the bus outside the first power source 1 and the second power source 2 (fig. 1, 2) or on both system neutral points (fig. 3), the second switching device 7 being able to connect either of the two or three phases of the bus to earth or a common conductor (i.e. if the first switching device 6 is connected to earth, the second switching device 7 is also connected to earth; if the first switching device 6 is connected to a common conductor, the second switching device 7 is also connected to a common conductor, thus forming a detection loop). In one embodiment, the second switching device 7 is a three-phase independent switch, and is respectively connected between a three-phase bus and the ground (fig. 1). In another embodiment, the second switching device 7 is a two-phase independent switch, and is respectively connected between the two-phase bus bar and the ground. In a third embodiment, the second switching device is a single-phase switch connected between the system neutral point and ground (fig. 3).

The partition switch 4 has an independent phase-splitting control function, that is, only one phase can be switched off. Or in another embodiment, the partition switch 4 is a three-phase ganged switch, and only three phases can be cut off simultaneously, and at this time, an auxiliary switch device 8 is provided, and the auxiliary switch device 8 is a three-phase independent switch, and is respectively connected with the three phases of the partition switch 4 in parallel, and can conduct any phase of the three phases which are cut off (fig. 1). Or in another embodiment the auxiliary switching means 8 are two independent switches connected in parallel with two phases of the sectional switch 4. At this time, if the first switching device 6 also sets two-phase switches at the same time, two phases of the auxiliary switching device 8 are set to be shifted by one phase from two phases of the first switching device 6 (i.e., two phases of the first switching device 6 and two phases of the auxiliary switching device 8 cannot be exactly the same two phases, fig. 2).

The dual-power supply system can process the interphase short-circuit fault in the following way: assuming that an inter-phase short-circuit fault occurs in the BC two-phase at point F (point F is random), the active-side partition switch 41 (which is a partition switch on the power supply side supplying power to the fault point at this time because the boundary switch 3 is in an off state) is first used to cut off the fault current (assuming that the C phase is cut off and the B phase is kept on, specifically, the BC two-phase is cut off at the same time and then the B phase is restored to be on, or only the C phase is cut off and the B phase is kept on itself), then the C phase is grounded at the lower port of the active-side partition switch 41 by using the first switching device 6, and then the a phase or the C phase is circularly grounded or continuously grounded at the upper port of the active-side partition switch 41 by using the second switching device 7 (the two phases are both charged, generally on the bus of the first power supply 1, and also can be grounded through the neutral point), so that a detection loop including two fault phase conductors (i.e., the BC phase) and the short-phase is constructed, and will generate a current pulse or a continuous current, the section switch 5 has the capability of detecting the current pulse or the current duration and can be switched off according to a first preset condition, where the number of current pulses switched off near the active side section switch 41 is greater than the number of current pulses switched off far away from the active side section switch 41, or the current duration switched off near the active side section switch 41 is longer than the current duration switched off far away from the active side section switch 41, so that the closest section switch 51 of the point F on the side of the active side section switch 41 can be guaranteed to be switched off (for more details, see patent application 2020114536325 and patent application 2020114536310). Then, the demarcation switch 3 is closed, and the point F remains as an inter-phase short-circuit fault point with respect to the second power supply 2 (new power supply to the point F), and is also processed and cut off in a similar manner. Specifically, the operation of the new source-side zone switch 42 (i.e., the zone switch on the new power source side) is controlled by the differential protection system to keep the B-phase on and the C-phase off (the B-phase off and the C-phase on may be also switched on, and hereinafter, the B-phase on and the C-phase off are taken as an example), then the C-phase is grounded at the lower port of the new source-side zone switch 42 by the first switch device 6 (the upper port and the lower port of the switch refer to the connection ports on both sides of the switch simply in terms of the structure of one switch, but when the switch is placed in the power supply system to discuss the processing logic in conjunction with the power source, the upper port refers to the side where the switch is electrically connected to the power source, the lower port refers to the other side where the upper port and the lower port are different depending on the power source, and then the a-phase or the C-phase on the side of the second power source-side zone switch 2 is placed at the upper port of the new source-side zone switch 42 by the second switch device 7 (both are electrically connected, the neutral point of the power supply 2 may also be grounded, typically on the bus of the second power supply 2), so that another detection loop including two faulty phase conductors and an interphase short-circuit point F is constructed, and a new current pulse or a persistent current is injected, and similarly, the closest section switch 52 of the point F on the new source side section switch 42 side may be tripped, so as to cut off the short-circuit fault of the point F with respect to the power supply 2 (only one section switch is shown on both sides of F in fig. 1, and actually, there may be a plurality of section switches). After the fault of the point F is removed, the active-side partition switch 41 and the new-source-side partition switch 42 are closed to resume power supply. In this embodiment, the active side partition switch is a partition switch capable of cutting off electric energy transmission of a protection area where an interphase short-circuit fault point is located before the boundary switch 3 is closed; the new source side zone switch is a zone switch which can cut off the electric energy transmission of the protection zone where the interphase short-circuit fault point is located after the demarcation switch 3 is closed (if the short-circuit fault point F is located on the other side of the demarcation switch 3, the operation principle is the same).

In the above embodiment, the active-side partition switch 41 may have a split-phase independent control function, that is, only the C-phase may be turned off while the B-phase is kept on, so that the fault current may be smoothly turned off. Alternatively, the active-side partition switches 4 are simultaneously turned off in three phases, and then closed in a single phase by the auxiliary switching device 8 to turn on the B phase again.

In the above embodiment, when the current pulse is generated, the second switching device 7 may be cyclically turned on, the first switching device 6 may be cyclically turned on, or the auxiliary switching device 8 may be cyclically turned on.

In one embodiment, the first switching device 6 and the second switching device 7 can also be connected to the same common line 10 (fig. 4) without being connected to ground, so that a detection circuit can also be produced.

In the above embodiment, a current limiting resistor 9 may be connected in series between the first switching device 6 and the ground (or the common conductor), or a current limiting resistor may be connected in series between the second switching device and the ground (or the common conductor) to limit the short-circuit current.

Preferably, one of the first switch device 6 and the second switch device 7 can be an electronic power switch, such as a thyristor, so as to conveniently perform instant on-off cycling control; the current limiting resistor can be a variable resistor, or a resistor with a fixed resistance value, and can also be a variable resistor box (figure 5). In one embodiment, the variable resistor box 9 includes a driving circuit and a plurality of resistors 901 with different resistance values, each of the resistors 901 is connected in series with a resistor switch 902 to form a series unit, all the series units are connected in parallel, the driving circuit is used to receive a signal of a short-circuit current value transmitted by a power supply system, and then the signal of a selected resistor is calculated and output, so as to drive the resistor switch 902 to operate, so that a suitable resistor can be selected, the current of a detection loop is in a control range, and thus the capability of the section switch 5 to cut off the current is suitable. In particular, the resistor in one of the series units is a wire 903, so that a resistor with a zero resistance can be connected in series.

If three-phase interphase short circuit fault occurs, two fault phases need to be cut off simultaneously, one fault phase is kept to be conducted, then one cut-off fault phase is grounded from the lower port of the corresponding partition switch, and other operations are the same. For additional details, see also patent application 2021106183754.

The above embodiments are merely illustrative of the concept and implementation of the present invention, and are not restrictive, and technical solutions that are not substantially changed under the concept of the present invention are still within the scope of protection.

Claims (8)

1. A double-power-supply power supply system convenient for fault processing comprises a first power supply and a second power supply, wherein a three-phase line is arranged between the first power supply and the second power supply, a demarcation switch is arranged on the three-phase line, and a plurality of partition switches and section switches are arranged on the three-phase line on two sides of the demarcation switch; the upper port and the lower port of the partition switch are provided with first switch devices, the first switch devices can connect any phase of two phases or three phases with the ground or a common conductor, second switch devices are arranged on buses or system neutral points of a first power supply and a second power supply, the second switch devices can connect any phase of two phases or three phases of buses or system neutral points with the ground or the common conductor, and the partition switch also has one of the following conditions:

(a) the partition switch can be controlled in a split phase mode so as to cut off any phase;

(b) the partition switch is in three-phase linkage cutting off, an auxiliary switch device is arranged in parallel with the partition switch, and when the partition switch cuts off a three-phase line, the auxiliary switch device can conduct two or any one of three phases of the cut-off three phases.

2. The dual power supply system facilitating fault handling of claim 1, wherein: the first switch device is a two-phase independent or three-phase independent switch connected between the upper port or the lower port of the partition switch and the ground or the common conductor, the second switch device is a two-phase independent or three-phase independent switch connected between the bus and the ground or the common conductor, or the second switch device is a single-phase switch connected between the system neutral point and the ground or the common conductor.

3. The dual power supply system facilitating fault handling of claim 1, wherein: a current limiting resistor is connected in series between the first switching device and the earth or the common lead, or a current limiting resistor is connected in series between the second switching device and the earth or the common lead.

4. The dual power supply system facilitating fault handling of claim 1, wherein: the second switching device is an electronic power switch.

5. The dual power supply system facilitating fault handling of claim 1, wherein: the second switching device is a thyristor.

6. The dual power supply system facilitating fault handling of claim 3, wherein: the current limiting resistor is a variable resistor box.

7. The dual power supply system facilitating fault handling of claim 1, wherein: and a differential protection system is arranged on two adjacent partition switches.

8. The dual power supply system facilitating fault handling of claim 1, wherein: the current information is current pulse or continuous current, and the section switch can cut off a line according to the preset current pulse number or current duration.

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