JPH03107314A - Lead in system of overhead power line to substation - Google Patents

Abstract

PURPOSE:To reduce lightning surge in good balance among phases by connecting the bushings of phases having long bus bars at the lead-in section of a substation comprising a gas insulated switchgears to the lower power lines of a closest steel tower and connecting the bushings of phases having short bus bars to the upper power lines of the closest steel tower. CONSTITUTION:The lead-in section 1 for a substation comprises air/gas bushings 3-8, gas bus bars 9-14, line breakers 15-20, and lightning arresters 21-26, which are connected to main bus bars 40 and 41. The power line upper, intermediate, and lower phases 100, 101, and 102 of the first line 50 on a steel tower 2 are connected to bushings 23, 22, and 21 respectively and the power line upper, intermediate, and lower phases 103, 104, 105 of the second line 51 are connected to bushings 24, 25, and 26 respectively. That is, the bushings of the phases with the longest gas bus bars are connected to the lower-phases power lines and the bushings of the phases with the second longest gas bus bars are connected to the intermediate-phase power lines.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a combination of a lead-in section structure and a lead-in overhead power line in a substation or switchyard, and particularly relates to a substation using gas-insulated switchgear [(GIS)]. , and a combination suitable for switching stations.

[Conventional technology]

Conventionally, regarding insulation coordination in substations, the Institute of Electrical Engineers of Japan Electrical Standards Investigation Committee standard “Zinc oxide type lightning arrester JJEC-217-1
984. In other words, an approximate expression showing the relationship between the distance between the lightning arrester and the protected device and the lightning surge voltage generated in the device is given by equation (4), and the lightning surge voltage increases with distance until the distance increases to a certain area. has been shown to increase.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give detailed consideration to the arrangement of overhead power lines drawn into substations and switchyards and the lightning surge voltage generated in protected equipment, and does not provide detailed information on means of insulation coordination in substations. It wasn't.

An object of the present invention is to provide a GIS substation and a switchyard that are more compact and economical from the standpoint of lightning insulation.

[Means to solve the problem]

In order to achieve the above objective, the bushing of the phase with the long lead-in bus of the GIS substation is connected to the power line at the bottom of the nearby steel tower, and the bushing of the phase with the short bus bar is connected to the power line on the top of the nearby steel tower. be.

[Effect]

As the distance between the lightning arrester and the protected equipment increases to a certain value, the lightning surge voltage generated in these equipment increases.

On the other hand, when a steel tower or an overhead ground wire is struck by lightning, the lightning surge voltage at each part of the tower becomes very high. in general,
For power lines arranged vertically to a steel tower, when a reverse flashover occurs due to an arcing horn, the lightning surge voltage appearing on the upper power line will be higher than that on the lower side.

GIS substations are made as compact as possible.

In addition, in order to be economical, the length of the lead-in busbar of the substation is different for each phase.

Therefore, from this relationship, if the phase with a long lead-in bus bar is connected to the power line located below the nearby steel tower.

With a good balance between each phase, it is possible to reduce the lightning surge voltage generated in the protected equipment as a whole.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a plan view mainly showing the lead-in section 1 and the first steel tower 2 of the substation, and FIG. 2 is a corresponding side view. The substation lead-in section 1 has air/gas bushings 3 to 8. Gas bus lines 9-14. Line breakers 15-20. It is composed of lightning arresters 21 to 26, which are connected to main bus bars 40 and 41, and the main bus bars are connected by a tie breaker 42. Note that the right side of the main busbar, transformer, etc. are omitted.

In the first steel tower 2, two power lines 50 and 51 are installed on tower arms 52 and 53. In addition, the overhead ground wire 60,6
1.62 is the restraining steel structure 7 of the substation lead-in part 1 from the first steel tower 2
It is constructed at 0.71.72.

Now, as shown in the side view of FIG. 2, the power lines are arranged vertically, and usually the upper phase is 80 degrees, the middle phase is 81 degrees, and the middle phase is 81 degrees from the top. It is called the lower phase 82.

The power line upper phase 100 of the first line 50. Middle phase 101゜Lower phase 1
02 are connected to bushings 23, 22.21, respectively. The same applies to the second line 51, and the power line upper phase 103. Middle phase 1o4゜Lower phase 105 is bushing 2
4, 25, and 26.

That is, for each circuit, the bushing of the phase with the longest gas bus bar is connected to the lower phase power line, the bushing of the phase with the next longest gas bus line is connected to the middle phase power line, and the remaining bushings are connected to the upper phase power line. are connected to each other.

Here, both lines use the connection method described above,
This connection method may not necessarily be used for lines with short gas bus lines.

Figure 3 shows the relationship between the distance Q of the gas bus from the lightning arrester branch point to the line breaker and the lightning surge voltage generated at the opened circuit breaker point (open end).
．． Middle phase 81. This is the result obtained using the reverse flashover in the lower phase 82 as a parameter. The first gas bus length ρ is long.
In a case like gas bus line 9 in the figure (its length is Q^)
When the upper phase power line 80 is connected to the bushing 21 with this bus bar 9, the lightning surge voltage V increases to VH, and when it is connected to the lower phase power line 82, the lightning surge voltage V can be lowered to VH. When the gas bus length Q is short Qc, even if the upper phase power line 80 is connected to the bushing with this gas bus, the voltage will not rise to the level of VH, but Vm'. That is, as shown in FIG. 3, the lightning surge voltage generated in the open circuit breakers of each phase can be reduced to about VL on average in a well-balanced manner, and rationalization of the insulation of the GIS can be achieved.

Note that in Fig. 1, the right side of the main bus line is omitted, but in order to shorten the length of this main bus line as much as possible, the first
There is a difference in the length of the gas bus bar of the lead-in section 1 in the figure. Shortening the main bus bar reduces the overall site area of the substation, and
This contributes to making the main bus itself more compact and improving economic efficiency.

According to this embodiment, it is possible to rationally suppress the lightning surge voltage generated in the open circuit breaker in the substation lead-in section, and to provide a GIS substation that is compact and economical from the viewpoint of lightning insulation. can do.

A variant according to the invention may be such that the bushing leading to the longest busbar in at least one line is connected to the lowest lower power line in the nearest tower. In this case, no matter how the remaining two-phase connections are selected, there is no significant difference in the lightning surge voltage generated in the GIS.

Another variant according to the invention can be such that at least one outer bushing at the substation entry is connected to the lowest lower power line at the tower. This is because, generally, the busbar connected to the outer bushing at the lead-in portion is the longest.

FIG. 4 shows an application example of the present invention in a single line diagram.

This is the case when multiple steel towers are used and their heights are different. In FIG. 4, power lines 101, 1 of the taller tower 100 are shown.
02 are connected to lead-in bushings 105, 106 connected to the short busbars 103, 104, and power supplies 8201, 202 of the lower tower 200 are connected to lead-in bushings 205, 206 connected to the long busbars 203, 204. In this way, it is possible to average out the lightning surge voltage that occurs over the entire lead-in area.

〔Effect of the invention〕

According to the present invention, even if the line breaker or disconnector of a substation that uses gas-insulated switchgear is in an open state and lightning surge voltage due to reverse flashover intrudes, the line breaker can be connected from the lightning arrester branch point to the line breaker. According to the length of the gas bus bar, it can be connected to the power line at an appropriate position in the vertical arrangement, so the lightning surge voltage generated at the open circuit breaker (or disconnector) can be reasonably suppressed, and the lightning-resistant design From this point of view, it is possible to provide a more compact and economical gas-insulated substation and switchyard.

[Brief explanation of drawings]

FIG. 1 is a plan view mainly showing the substation lead-in part and the first steel tower according to an embodiment of the present invention, and FIG. 2 is a side view corresponding to FIG. 1.
FIG. 3 is a relationship diagram between gas bus length and lightning surge voltage, and FIG. 4 is a single line diagram showing another embodiment of the present invention. 1... Substation lead-in section, 2... First steel tower, 3-8...
・Bushing, 9~14... Gas bus bar, 15~20・
...Railway lol 1 Figure 2 Figure 3 No- Figure 4

Claims (1)

[Scope of Claims] 1. A lead-in part of a substation using a gas-insulated switchgear in which each phase bus in at least one line from a line breaker to a line lightning arrester has a different length, and a steel tower near the substation and vertically arranged power lines, each phase bushing connected to a long, medium, or short bus bar in at least one circuit and the power line whose height at the tower is lower, intermediate, or upper. A system for connecting overhead power lines to a substation, which is characterized by being connected to each substation. 2. Each bus bar in at least one circuit from a line breaker to a line surge arrester is arranged vertically at the lead-in part of a substation using gas-insulated switchgear and a steel tower near the substation. A method for bringing an overhead power line into a substation, which connects a power line to a substation, characterized in that a bushing connected to the longest bus bar in at least one circuit is connected to the lowest lower power line on the tower. . 3. At the lead-in part of a substation or switchyard, the length of the busbar from the line breaker to the line lightning arrester on at least one side of the outside of the lead-in part of a substation or switchyard is longer than the length of the busbar of the other phase. For connecting vertically arranged power lines on a steel tower near a substation, the outer bushing on at least one side of the lead-in part is connected to the lower power line at the lowest height on the tower. A system for connecting overhead power lines to a substation, which is characterized by: 4. Under the conditions that the bus length between the lines at the substation lead-in part is different and the height of the nearby steel tower is different, the lead-in part of the line with the long bus bar and the power line of the low tower are connected to the power line of the short line of the bus bar. An overhead power line lead-in method to a substation characterized by connecting the lead-in part to a power line on a high steel tower.