JP7794038B2 - Wiring method for circular distribution line, and circular distribution line - Google Patents

Description

The present invention relates to a wiring method for a circular distribution line and to a circular distribution line.

Various types of busbar configurations (e.g., three-phase, three-wire distribution lines) have been proposed for use in substations. Among these, ring busbars are known as highly reliable busbar configurations that are excellent at dealing with risks such as ground faults.

In a substation's ring bus, current flowing in from the transformer flows through the ring bus and is transmitted to the transmission line, but the path of the current flowing through this ring bus changes depending on the circuit configuration of the ring bus, the configuration of the transformer or transmission line, or changes in current or voltage. As a result, current flowing through the ring bus can circulate through the ring bus without flowing from the transformer to the transmission line (circulating current, or zero-phase circulating current). When circulating current occurs, it can cause protective relays in the circulating bus to malfunction, leading to the tripping of a circuit breaker. Therefore, it is important in substation operation to prevent circulating current as much as possible.

Circulating current is a phenomenon that can occur in circuits where current circulates. Regarding a method for suppressing circulating current in a switch, for example, Patent Document 1 describes a cross current compensation control system for a power system that includes a cross current detection compensator whose input terminal is connected to a cross-connection line that cross-connects the secondary sides of auxiliary current transformers, and whose output terminal is connected to a cross current compensation line that connects the secondary sides of multiple current transformers in series. When this cross current detection compensator detects a cross current circulating through a bus, distribution line, or switch, it supplies a compensation current to the cross current compensation line to cancel out the current component corresponding to the cross current that appears on the secondary side of the current transformer.

Japanese Patent Application Laid-Open No. 2003-189476

However, currently there is no effective means of dealing with the circulating current that occurs in the circulating bus of a substation.

The present invention was made in light of this current situation, and its purpose is to provide a wiring method for a ring-shaped power distribution line that can suppress circulating currents that occur in the ring-shaped power distribution line, and the ring-shaped power distribution line.

To achieve the above-mentioned objective, one aspect of the present invention is a wiring method for a circular distribution line composed of electric wires of multiple different phases, each of which is aligned, characterized in that the order in which the electric wires of the multiple phases are aligned in a first line section of the circular distribution line is reversed from the order in which the electric wires of the multiple phases are aligned in a second line section opposite the first line section.

The inventors have discovered that the circulating current occurring in the circulating bus can be suppressed by reversing the order in which the electric wires of each phase are arranged in the line section of the circulating bus from the order in which the electric wires of each phase are arranged in the line section opposite the line section. In this way, the wiring method for a circular distribution line of the present invention can suppress the circulating current occurring in the circular distribution line.

Furthermore, one aspect of the present invention for achieving the above-mentioned object is a wiring method for a circular distribution line, characterized in that the order in which the electric wires of the multiple phases are arranged in the line portion of the distribution line on the side where current flows into the circular distribution line is reversed from the order in which the electric wires of the multiple phases are arranged in the line portion of the distribution line on the side where current flows out of the circular distribution line.

In this way, by reversing the order in which the electric wires of each phase are arranged on the line section where current flows into the ring distribution line and the line section where current flows out of the ring distribution line, the circulating current occurring in the circulating bus can be more reliably suppressed.

Furthermore, one aspect of the present invention for achieving the above-mentioned object is a circular distribution line composed of electric wires of multiple different phases, each of which is aligned, characterized in that the order in which the electric wires of the multiple phases are aligned in a first line section of the circular distribution line is reversed to the order in which the electric wires of the multiple phases are aligned in a second line section opposite to the first line section.

Furthermore, one aspect of the present invention for achieving the above-mentioned object is a circular distribution line, characterized in that the arrangement order of the electric wires of the multiple phases in the line portion of the distribution line on the side where current flows into the circular distribution line is reversed from the arrangement order of the electric wires of the multiple phases in the line portion of the distribution line on the side where current flows out of the circular distribution line.

This invention makes it possible to suppress circulating currents that occur in circular distribution lines.

FIG. 2 is a diagram illustrating an example of the configuration of a circulation bus, which is a ring-shaped distribution line in the present embodiment. FIG. 2 is a diagram showing an example of a wiring configuration of a circulation bus according to the present embodiment. 3 is a diagram of the circulating bus shown in FIG. 2 as viewed from the side (the first line portion side). FIG. FIG. 1 is a circuit diagram of a circulating bus set for an XTAP in this embodiment. FIG. 10 is a diagram showing the effective values and phase values of the current in each switch in the conventional case and the invention case. FIG. 10 is a diagram showing values of circulating current (zero-phase current) generated in a switch in each of the conventional case and the invention case. FIG. 10 is a diagram showing values of circulating current (zero-phase current) generated in a switch in each of the conventional case and the invention case. FIG. 1 is a diagram showing an example of a wiring configuration of a conventional circulation bus.

Below, a wiring method for a ring-shaped distribution line and the ring-shaped distribution line according to one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows an example of the configuration of a circulation bus, which is a ring-shaped distribution line in this embodiment. This circulation bus 10 is a ring-shaped distribution line and is installed, for example, in a substation. Electric lines 21 (high-voltage side) from multiple transformers 20 and multiple transmission lines 30 (low-voltage side) are connected to the circulation bus 10. The transmission lines 30 are connected to consumers, etc. (not shown).

The circulation bus 10 is composed of a bus bar A 11 on the transformer 20 side, a bus bar B 12 on the transmission line 30 side, a first track section 13 connecting one end of the bus bar A 11 to one end of the bus bar B 12, and a second track section 14 connecting the other end of the bus bar A 11 to the other end of the bus bar B 12. Hereinafter, the side of the circulation bus bar 10 with the first track section 13 will be referred to as the "first side," and the side with the second track section 14 will be referred to as the "second side."

In this embodiment, the A busbar 11 and the B busbar 12 each constitute tracks in the longitudinal direction of the circulating busbar 10 and are positioned opposite each other. Furthermore, the first track portion 13 and the second track portion 14 each constitute tracks in the minor axis direction of the circulating busbar 10 and are positioned opposite each other.

The electric wires 21 from each high-voltage transformer 20 are connected to a bridging electric wire 15 that bridges between a predetermined position on the A bus 11 and a predetermined position on the B bus 12. A disconnector 16 is provided at a predetermined position on the bridging electric wire 15 on the A bus 11 side of the connection point of the bridging electric wire 15, and at a predetermined position on the bridging electric wire 15 on the B bus 12 side of the connection point of the bridging electric wire 15.

Each low-voltage transmission line 30 is connected to a connection on a bridging wire 17 that bridges between a predetermined position on the A bus 11 and a predetermined position on the B bus 12. A disconnector 18 is provided at a predetermined position on the bridging wire 17 on the A bus 11 side of the connection on the bridging wire 17, and at a predetermined position on the bridging wire 17 on the B bus 12 side of the connection on the bridging wire 17.

Furthermore, circuit breakers 19 are provided at predetermined positions on the A bus bar 11, the B bus bar 12, the first track section 13, and the second track section 14.

In the above configuration, electricity from the transformer 20 flows into the A bus 11 of the circulation bus 10, and the current flows through one of the lines of the circulation bus 10, and then flows out from the B bus 12 to the transmission line 30.

For example, if a worker confirms that a circulating current has occurred in the circulation bus 10, causing an abnormality, he or she can operate the circuit breaker 19 closest to the abnormality to cut off the current near the abnormality, and by switching the disconnectors 16, 18 on the bridging wires 15, 17, it is possible to ensure a path for current transmission from the transformer 20 via the circulation bus 10 to the transmission line 30 without using the line near the abnormality. However, this type of work is extremely complicated, and it is desirable to prevent circulating currents from occurring as much as possible.

Next, Figure 2 shows an example of the wiring configuration of the circulation bus 10 of this embodiment. This circulation bus 10 consists of three three-phase wires arranged in a roughly parallel alignment. Specifically, the circulation bus 10 consists of three wires: a first-phase wire 51 (red), a second-phase wire 52 (white), and a third-phase wire 53 (blue).

Here, conventionally, the arrangement direction of the first-phase electric wire 51 (red), second-phase electric wire 52 (white), and third-phase electric wire 53 (blue) is the same for both the A bus 11 and the B bus 12. For example, as shown in Figure 8, for both the A bus 11 and the B bus 12 of the circulation bus 10, the first-phase electric wire 51 (red), second-phase electric wire 52 (white), and third-phase electric wire 53 (blue) are aligned in this order from the high-voltage side (transformer 20 side) to the low-voltage side (transmission line 30 side).

Furthermore, the arrangement direction of the first phase electric wire 51 (red), second phase electric wire 52 (white), and third phase electric wire 53 (blue) is the same for the first line portion 13 and the second line portion 14. For example, as shown in FIG. 8, for both the first line portion 13 and the second line portion 14 of the circulation bus 10, the first phase electric wire 51 (red), second phase electric wire 52 (white), and third phase electric wire 53 (blue) are aligned in this order from the first side to the second side.

However, in the circulation bus 10 of this embodiment, the arrangement directions of the first phase electric wire 51 (red), second phase electric wire 52 (white), and third phase electric wire 53 (blue) are reversed between the A bus 11 and the B bus 12.

That is, for example, as shown in FIG. 2, the three wires in the A bus 11 of the circulation bus 10 are arranged in the order of first-phase wire 51 (red), second-phase wire 52 (white), and third-phase wire 53 (blue) from the high-voltage side (transformer 20 side) to the low-voltage side (transmission line 30 side), while the three wires in the B bus 12 of the circulation bus 10 are arranged in the order of third-phase wire 53 (blue), second-phase wire 52 (white), and first-phase wire 51 (red) from the high-voltage side (transformer 20 side) to the low-voltage side (transmission line 30 side). In other words, the arrangement order of the wires is reversed between the A bus 11 and the B bus 12.

Note that while the above describes red-white-blue and blue-white-red arrangements, other color patterns are also acceptable (for example, blue-white-red and red-white-blue).

Furthermore, in the circulation bus 10 of this embodiment, the arrangement directions of the first phase electric wire 51 (red), second phase electric wire 52 (white), and third phase electric wire 53 (blue) are reversed from the first line portion 13 and the second line portion 14.

For example, as shown in FIG. 2, the three wires in the first line section 13 of the circulation bus 10 are aligned from the first side to the second side in the order of first phase electric wire 51 (red), second phase electric wire 52 (white), and third phase electric wire 53 (blue), while the three wires in the second line section 14 of the circulation bus 10 are aligned from the first side to the second side in the order of third phase electric wire 53 (blue), second phase electric wire 52 (white), and first phase electric wire 51 (red). In other words, the alignment order of the wires is reversed between the first line section 13 and the second line section 14.

Note that while the above describes red-white-blue and blue-white-red arrangements, other color patterns are also acceptable (for example, blue-white-red and red-white-blue).

Note that Figure 3 is a side view (from the side of the first line section 13) of the circulation bus 10 shown in Figure 2. The circulation bus 10 is supported by a support member 32 erected on the substation site 3, and is fixed at a predetermined height from the circulation bus 10. The plane of the circulation bus 10 is set approximately parallel to the surface of the site 3.

Specifically, the A busbar 11 of the circulation busbar 10 is aligned approximately parallel to the surface of the site 31 from the high-voltage side (transformer 20 side) to the low-voltage side (transmission line 30 side) in the order of first-phase electric wire 51 (red), second-phase electric wire 52 (white), and third-phase electric wire 53 (blue). Furthermore, the B busbar 12 of the circulation busbar 10 is aligned approximately parallel to the surface of the site 31 from the high-voltage side (transformer 20 side) to the low-voltage side (transmission line 30 side) in the order of third-phase electric wire 53 (blue), second-phase electric wire 52 (white), and first-phase electric wire 51 (red).

In this way, by reversing the order in which the electric wires of each phase are arranged in the first track section (A busbar 11, first track section 13) of the circulation busbar 10 and the second track section (B busbar 12, second track section 14) opposite the first track section, it is possible to suppress the circulating current that occurs in the circulation busbar. This reduces the frequency with which workers have to perform tedious response work, such as operating circuit breakers 19 and disconnectors 16 and 18, due to the occurrence of circulating current.

<Example>
Next, the inventors have clarified that the circulating current can be suppressed by using a circulating bus bar employing the above-described wiring configuration, by constructing and executing the following simulation model.

The simulation model used by the inventors is XTAP (registered trademark) (Central Research Institute of the Electric Power Industry), an instantaneous value analysis program. The wire layout was input into XTLC, an impedance calculation program installed in XTAP, to determine the impedance of each element in the circuit, and the determined impedance was then input into XTAP to determine the circulating current generated in the circulating bus.

Figure 4 is a circuit diagram of the circulating bus set up for the XTAP in this embodiment. This circulating bus 300 consists of bus A 310, to which wires from first current source 301 and second current source 302 (each assumed to be a transformer) are connected, as well as wires to third current source 303 and fourth current source 304 (assumed to be a transmission line to a consumer), bus B 315, to which wires to fifth current source 305 (assumed to be a transmission line to a consumer) are connected, first bridge wire 320 connecting one side of bus A 310 to one side of bus B 315, and second bridge wire 325 connecting the other side of bus A 310 to the other side of bus B 315. Additionally, connection line 326, which connects a predetermined position on bus bar A 310 with a predetermined position on bus bar B 315, is connected to a wire to sixth current source 306 (assuming it is a transmission line to a consumer). These current sources simulate the current flowing into or out of circulation bus bar 300.

In addition, a switch 360 is provided on the A bus 310, a switch 370 is provided on the B bus 315, a switch 350 is provided on the first cross-linking wire 320, and a switch 340 is provided on the second cross-linking wire 325.

In addition, a switch 332 is provided on the electric wire 361 from the first current source 301. A switch 331 is provided on the electric wire 362 from the second current source 302. A switch 344 is provided on the electric wire 363 to the third current source 303. A switch 342 is provided on the electric wire 364 to the fourth current source 304. A switch 343 is provided on the electric wire 365 to the fifth current source 305. A switch 341 is provided on the electric wire 366 to the sixth current source 306.

Based on the above circuit configuration, we set up two cases: a conventional case where the circulation bus 300, which is a three-phase, three-wire distribution line, is wired in a conventional manner (hereinafter referred to as the conventional case), and a case where the wiring according to this embodiment is used (hereinafter referred to as the inventive case). Then, for each of the conventional case and the inventive case, we simulated how current flowed through the circulation bus 300 by passing it from each current source.

Specifically, in the conventional case, the first-phase electric wires (red), second-phase electric wires (white), and third-phase electric wires (blue) on each of the A busbar 310 and B busbar 315 of the circulation busbar 300 were aligned in this order from the side of the first current source 301, etc. (assuming the substation side) toward the side of the fifth current source 305, etc. (assuming the transmission line side). Furthermore, the first-phase electric wires (red), second-phase electric wires (white), and third-phase electric wires (blue) on each of the first cross-linking wire 320 and second cross-linking wire 325 of the circulation busbar 300 were aligned in this order from the side of the first cross-linking wire 320 (assuming the first side) toward the side of the second cross-linking wire 325 (assuming the second side).

In the invention case, the first-phase electric wire (red), second-phase electric wire (white), and third-phase electric wire (blue) in the A bus 310 of the circulation bus 300 were aligned in this order from the side of the first current source 301, etc. (assuming the substation side) toward the side of the fifth current source 305, etc. (assuming the transmission line side). On the other hand, in the B bus 315 of the circulation bus 300, the third-phase electric wire (blue), second-phase electric wire (white), and first-phase electric wire (red) were aligned in this order from the side of the first current source 301, etc. (assuming the substation side) toward the side of the fifth current source 305, etc. (assuming the transmission line side).

In addition, in the invention case, the first-phase electric wire (red), second-phase electric wire (white), and third-phase electric wire (blue) in the first cross-linking wire 320 of the circulation bus 300 were aligned in this order from the first cross-linking wire 320 side (assumed to be the first side) toward the second cross-linking wire 325 side (assumed to be the second side). On the other hand, in the second cross-linking wire 325 of the circulation bus 300, the third-phase electric wire (blue), second-phase electric wire (white), and first-phase electric wire (red) were aligned in this order from the first cross-linking wire 320 side (assumed to be the first side) toward the second cross-linking wire 325 side (assumed to be the second side).

Figure 5 shows the effective current value and phase values for each switch in the conventional and inventive cases. In the figure, "lm" indicates the effective current value (unit: A), and "Ph" indicates the phase (unit: deg). The numbers on the switches correspond to the reference symbols in the drawings attached to the switches described above. Additionally, "a," "b," and "c" respectively indicate the first, second, and third phases of the circulation bus 300. These settings simulated the current flowing into and out of the circulation bus 300.

Figure 6 also shows the values of the circulating current (zero-phase current) generated in the switch 360 in both the conventional and inventive cases. As shown in the figure, a circulating current of 226.39 mA was generated in the conventional case, while in the inventive case, this was reduced to 102.59 mA, less than half the amount.

In this way, it was found that the circulating current can be significantly reduced by reversing the arrangement of the three wires (three phases) in the circulating busbars, namely, by reversing the arrangement of the three wires (three phases) in the A busbar with the arrangement of the three wires (three phases) in the B busbar, and by reversing the arrangement of the three wires (three phases) in one bridge wire with the arrangement of the three wires (three phases) in the other bridge wire.

As described above, the circular distribution line and wiring method for the circular distribution line of this embodiment can suppress circulating currents generated in the circulation bus by reversing the order in which the electric wires of each phase are arranged in the line portion (A bus 11, first line portion 13) of the circulation bus 10 and the line portion (B bus 12, second line portion 14) opposite the line portion.

In particular, the circular distribution line and wiring method for the circular distribution line of this embodiment reverses the order in which the electric wires of each phase are arranged in the A bus 11, which is the side where current flows into the circulation bus 10, and the order in which the electric wires of each phase are arranged in the B bus 12, which is the line portion where the current that has flowed through the circulation bus 10 flows out, thereby more reliably suppressing the circulating current that occurs in the circulation bus.

The above description of the embodiments is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention may be modified or improved without departing from its spirit, and equivalents thereof are also included within the scope of the present invention.

For example, while this embodiment describes a circular bus in a substation, the present invention can also be applied to circular distribution lines in facilities other than substations.

In addition, while the circulation bus in this embodiment is three-phase, three-wire, the present invention can also be applied to other types of distribution lines, i.e., lines made up of wires of multiple different phases, each of which is aligned (for example, a three-phase, four-wire system).

10 Circulation bus 11 A bus 12 B bus 13 First line section 14 Second line section 20 Transformer 30 Transmission line

Claims (2)

A wiring method for a circular distribution line that is made up of electric wires of different phases and in which the electric wires are aligned, comprising:
an arrangement order of the electric wires of the multiple phases in a first line portion of the annular distribution line, on a side where a current flows into the annular distribution line , is reversed from an arrangement order of the electric wires of the multiple phases in a second line portion opposite to the first line portion, on a side where a current that has flowed through the annular distribution line flows out ;
A wiring method for a ring distribution line, comprising: A circular distribution line is made up of electric wires of different phases, each of which is aligned,
an arrangement order of the electric wires of the multiple phases in a first line portion of the annular distribution line, on a side where a current flows into the annular distribution line , is reversed from an arrangement order of the electric wires of the multiple phases in a second line portion opposite to the first line portion, on a side where a current that has flowed through the annular distribution line flows out ;
A circular distribution line characterized by: