JP2001197617A - Switchgear at electric power station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a switchgear at an electric power station, that prevents short circuit caused by lightning between electrodes of a breaker, even when multiple lightning strokes occurs on aerial transmission lines and lightning surges from a plurality of transmission lines enter breakers of the line unit of the switchgear connected to the transmission lines of the aerial transmission lines. SOLUTION: A main bus line is connected in series to a main bus line side isolator, a breaker and a line side isolator, and parallel lightning arresters in which zinc oxide elements are stacked in series are connected parallel to the breakers of the line unit of the switchgear at an electric power station, in which line lightning arresters are arranged between the end of the line side isolator and ground. The ends of the line side are connected to the transmission lines of the aerial transmission lines, and the main bus line side isolators are connected to the main bus line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switchgear for an electric substation, which is installed in an electric substation such as a power plant or a substation and includes a plurality of line units connected to an overhead transmission line.

[0002]

2. Description of the Related Art FIG. 12 is a single-line diagram of a line unit of a conventional switchgear connected to a transmission line of an overhead transmission line of an electric station such as a power plant or a substation. FIG. 13 is a side view showing a case where the line unit portion of the single line diagram of FIG. 12 is configured by an air-insulated device. In the drawing, 1 is a main bus, 2a is a first line unit, 2b is a second line unit, and each of the circuit breaker 3, the current transformer 4, the main bus-side disconnector 5, the line-side disconnector 6, and the line It is composed of an arrester 7.

[0003] 8a is a connection line between the main bus 1 and the main bus-side disconnector 5, 8b is a connection line between the main bus-side disconnector 5 and the circuit breaker 3, and 8c is a connection line between the circuit breaker 3 and the line side disconnector. 8d is a connection line between the line side disconnector 6 and the line arrester 7, and 8e is a connection line between the line arrester 7 and the power transmission line. 9 is an overhead transmission line, and the first line unit 2a
And a second power transmission line 9b connected to the second line unit 2b, which is mounted on both sides of the tower. An overhead ground wire is installed between the tops of the towers.

[0004] Circuit breakers generally used in power systems include:
When the generator steps out, a voltage of 2 / √3 times the rated voltage of the circuit breaker is applied, and it is necessary to withstand this voltage for a long time, so the withstand voltage between poles is 2 to 2.5 times the withstand voltage to ground. It has a withstand voltage of about 2 to 2.5 times the limit voltage of the line lightning arrester 7 with respect to the lightning surge voltage.

When the first line unit 2a and the second line unit 2b are connected to the first power transmission line 9a and the second power transmission line 9b of the overhead power transmission line 9, a tower or an overhead If there is a lightning strike on the ground wire, the electric potential of the tower rises, and a reverse flashover occurs in the arc horn of the insulator on which the first power transmission line 9a or the second power transmission line 9b of the overhead power transmission line 9 is mounted, thereby causing a ground fault. I do.

Assuming that the power transmission line having the ground fault is the first power transmission line 9a, the circuit breaker 3 of the line unit 2a in which the ground fault has occurred is opened to cut off the ground fault current. When the lightning strike is a multiple lightning strike, there is a lightning surge after the breaker 3 is opened, and the lightning surge limited to the voltage limit by the line arrester 7 enters the line-side electrode of the circuit breaker 3 in the opened state. Then, a lightning surge of the opposite polarity is generated from the adjacent power transmission line 9 b by the second line unit 2.
b, first track unit 2a opened around main bus 1
Of the lightning surge that has entered the main bus side electrode of the circuit breaker 3, and the surge voltage that is three times the limit voltage of the line arrester 7 is applied between the poles of the circuit breaker 3 due to reflection at the electrodes on both sides of the circuit breaker 3. Join.

When the overhead transmission line 9 composed of a plurality of power transmission lines 9a and 9b receives a lightning strike by multiple lightning, the ground fault current of the power transmission line that has been grounded is cut off, and the gap between the opened circuit breakers is cut off. A surge voltage three times the limit voltage of the line arrester 7 is applied,
Since this voltage greatly exceeds the withstand voltage level between the poles of the circuit breaker 3, a flashover occurs and a ground fault occurs again. When a flashover occurs between the electrodes of the open circuit breaker 3, the other circuit breaker concerned is opened by the operation of the bus protection relay, and the circuit in which the ground fault current flows is cut off.

As described above, when the switchgear connected to the overhead power transmission line of the conventional electric substation includes a plurality of power transmission lines, the circuit breaker of the line unit is subjected to multiple lightning strikes in the open state. Occasionally, the occurrence of inter-electron flashover cannot be prevented.

[0009]

As described above, in the conventional switchgear of an electric substation, multiple lightning strikes occur on the overhead transmission line 9, a ground fault occurs on the transmission line due to reverse flashing, and a circuit breaker is provided. When the overhead power transmission line is grounded and a lightning surge enters from multiple power transmission lines even after opening, a surge voltage three times the limit voltage of the line surge arrester is applied between the poles of the circuit breaker 3 and a flashover between poles occurs. There were problems that occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the structure of a switchgear of an electric substation is provided between poles in which a circuit breaker of a line unit is opened against multiple lightning strikes. An object of the present invention is to provide an electric station switchgear that can prevent flashover from occurring.

[0011]

According to a first aspect of the present invention, there is provided a switchgear for an electric substation in which a main bus and at least a circuit breaker are arranged, one of which is connected to the main bus, and the other of which is a power transmission line of an overhead transmission line. A parallel lightning arrestor with stacked zinc oxide elements is connected in parallel to a circuit breaker of a switchgear of an electric substation that has multiple line units with line arresters connected between the line and the connection to the power transmission line and the ground. It was done.

According to a second aspect of the present invention, there is provided a switchgear for an electric substation, wherein the circuit breaker according to the first aspect is housed in a tank whose cut-off portion is grounded and externally connected to both ends of the tank. Is a tank-type gas circuit breaker to which is attached. The parallel lightning arrester has a configuration in which stacked zinc oxide elements are housed in an insulator tube and is connected between upper terminals of a pair of bushings of the circuit breaker.

According to a third aspect of the present invention, there is provided a switchgear for an electric substation, wherein the circuit breaker according to the first aspect has a breaking portion in which an arc-extinguishing chamber and a switching electrode are accommodated in a porcelain tube, and a support for supporting the breaking portion. An insulator-type gas circuit breaker composed of an insulator part and a parallel lightning arrestor arranged in parallel with the insulation part of the insulator-type gas circuit breaker as a structure containing a zinc oxide element stacked in an insulator tube. It is a connected configuration.

According to a fourth aspect of the present invention, there is provided a switchgear for an electric substation, wherein a main bus and at least a circuit breaker are connected and accommodated in a tank, and a pair of bushings are attached to both ends of the tank. A bus bar is connected, and the other bushing has a configuration including a plurality of line units connected to the transmission line of the overhead power transmission line, between upper terminals of a bushing attached to both ends of a tank of a switchgear of an electric substation. The stacked zinc oxide elements are connected to a parallel lightning arrester housed in an insulator tube.

According to a fifth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the parallel lightning arrester according to any one of the second to fourth aspects is applied to a resin insulator tube formed of weather-resistant resin in a shape having a plurality of folds on an outer periphery thereof. This is a configuration in which the stacked zinc oxide elements are accommodated.

According to a sixth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the main bus accommodated in a grounded tank and at least a circuit breaker are connected and accommodated in a grounded tank,
A line arrestor housed in a tank grounded between the other end and the other end is arranged between the other end and the ground, and the other end is connected to an overhead transmission line via a bushing attached to the tank end. A zinc oxide element is laminated on a circuit breaker of a switchgear of an electric substation having the above-mentioned line unit, and a parallel lightning arrester housed in a grounded tank is connected in parallel to the circuit breaker.

According to a seventh aspect of the present invention, there is provided a switchgear for an electric substation, wherein the parallel lightning arrester having the structure according to the sixth aspect is stacked in a zinc oxide element, connected in parallel to a breaking portion of the circuit breaker, and arranged in a circuit breaker tank. The configuration is as follows.

According to an eighth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the limiting voltage of the parallel lightning arresters connected in parallel to the cut-off portions of the first to seventh aspects is the limit voltage of the line arrester arranged on the line side. It is set at about twice the limit voltage.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1
The switchgear of the substation is constructed with air insulation, the circuit breaker of the line unit is a tank-type gas circuit breaker, and flashing occurs between the opened poles of the circuit breaker of the line unit in response to multiple lightning strikes. This is a configuration that does not occur. FIG. 1 is a single-line diagram of a line unit portion of the switchgear for an electric substation according to the first embodiment, and FIG. 2 is a side view of a tank-type gas circuit breaker of the line unit in FIG. In the figure, a first power transmission line 9a and a second power transmission line 9b of a main bus 1, a current transformer 4, a main bus-side disconnector 5, a line-side disconnector 6, a line arrester 7, and an overhead transmission line 9 are conventional. 12 and 13 are the same as those shown in FIGS. Reference numeral 13 denotes a tank-type gas circuit breaker. As shown in FIG. 13, a shut-off portion 13a is accommodated in a tank 13b.
And a pair of bushings 13c attached to both ends. 13d is an operation device, and 13e is an insulating support member for supporting the blocking portion. Reference numeral 18 denotes a parallel lightning arrester connected between terminals of a bushing 13c attached to both ends of the tank 13b. 10a is the first track unit, 10
Reference numeral b denotes a second line unit, which includes a main bus-side disconnector 5, a tank-type gas circuit breaker 13, a line-side disconnector 6, a line arrester 7, and a parallel arrester 18, respectively.

The parallel lightning arrester 18 connected in parallel to the tank type gas circuit breaker 13 is a zinc oxide type lightning arrester having a zinc oxide element housed in an insulator tube, and its voltage limit is twice the voltage limit of the line lightning arrester 7. Set back and forth.

In the state where the first line unit 10a and the second line 10b of the switchgear of the electric substation thus constructed are connected to the overhead transmission line 9, the multiplexing is performed on the tower or the overhead ground line of the overhead transmission line 9. There is a lightning strike, and the power transmission line is grounded due to reverse flashing, and the ground fault current is interrupted.
3, a surge voltage that is three times the limit voltage of the line lightning arrester 7 is applied to the surge voltage applied between the poles, but the surge arrester 18 operates and the tank type gas circuit breaker 13 The flashover between poles is prevented, and the tank-type gas circuit breaker 13 serves as a switchgear of an electric station protected from lightning surge due to multiple lightning.

In the configuration of the air insulation system according to the first embodiment, a simple structure in which only the parallel lightning arrester 18 is connected between the ends of the bushing of the tank-type gas circuit breaker 3 having the conventional structure is employed. A switchgear for an electric station that is protected from flashing between poles of the tank-type gas circuit breaker 13 even when struck by lightning is obtained.

Embodiment 2 FIG. In the second embodiment, the switchgear of the electric substation is constructed by air insulation, the circuit breaker of the line unit is an insulator type gas circuit breaker, and the circuit breaker of the line unit is opened for multiple lightning strikes. This is a configuration in which no flashover occurs between the poles. FIG. 3 is a single-line diagram of the line unit of the switchgear for an electric substation according to the second embodiment, and FIG. 4 is a side view of the insulator-type gas circuit breaker of the line unit in FIG. In the figure, main bus 1, current transformer 4, main bus-side disconnector 5, line-side disconnector 6, line arrester 7, and power transmission line 9 of overhead transmission line
Reference numerals a and 9b are the same as those shown in FIGS. 12 and 13 of the related art.

Reference numeral 23 denotes an insulator type gas circuit breaker.
3a is formed by two-point cutting housed inside two porcelain tubes, mounted horizontally on both sides of a central upper tank portion 23c, and a closing resistor 23b is arranged in parallel with the cut-off portion 23a. 23c is supported by a support insulator 23d, and is attached to an upper portion of the operation device 23e of the gantry. Numeral 28 denotes a parallel lightning arrestor, which is formed by laminating a required number of two divided zinc oxide elements and housing them in two porcelain tubes.
3a, and is connected in parallel with the blocking unit 23a.

Reference numeral 20a denotes a first track unit, and 20b denotes a second track unit.
Insulator type gas circuit breaker 2 equipped with parallel lightning arrester 28
3, a line-side disconnector 6 and a line arrester 7. The limit voltage of the parallel lightning arrester 28 connected in parallel to the cutoff portion of the insulator type gas circuit breaker 23 is set to be about twice the limit voltage of the line lightning arrester 7.

In the conventional insulator type gas circuit breaker, a voltage dividing capacitor is attached to make the voltage sharing of the breaking portion uniform, but the zinc oxide element type parallel lightning arrester 28 has a voltage dividing action due to leakage current. In addition, a voltage dividing capacitor is not required.

In a state where the first line unit 20a and the second line 20b of the switchgear of the electric substation configured as described above are connected to the overhead transmission line 9, the transmission line 9 is multiplexed with the tower or the overhead ground line. When there is a lightning strike, a ground fault occurs in the transmission line due to a reverse flash and a ground fault current is interrupted. Lightning surge intrudes from the power transmission line, and the lightning surge applied between the poles is three times the limit voltage of the line lightning arrester 7, but the parallel lightning arresters 28 operate to prevent inter-electron flashover of the insulator type gas circuit breaker 23. Thus, the insulator-type gas circuit breaker 23 serves as a switchgear of an electric power plant protected from lightning surge due to multiple lightning.

Embodiment 3 Embodiment 3 is a composite gas insulated switchgear in which a main bus disconnector, a circuit breaker, and a line-side disconnector of a line unit of a switchgear of an electric substation are accommodated in a tank. It is configured so that flashover does not occur between the poles of the circuit breaker that has been opened. FIG. 5 is a single-line diagram of the track unit of the switchgear for an electric substation according to the third embodiment, and FIG. 6 is a side view of the track unit of FIG. In the figure, the main bus 1, the first power transmission line 9a and the second power transmission line 9b of the overhead power transmission line 9 are the same as the conventional units shown in FIGS.

Reference numeral 33 denotes a gas circuit breaker, 34 denotes a current transformer, 36 denotes a line-side circuit breaker, and 37 denotes a line lightning arrester.
3, the current transformer 34 and the line-side disconnector 36 are connected in series,
The track lightning arrestor 37 is a track side disconnector 36 housed in a tank.
And a pair of bushings 39 attached to both ends of the tank to form a combined switchgear. 33a is a circuit breaker operating device. A main bus-side disconnector 35 is disposed between the combined switchgear and the main bus 1. Reference numeral 38 denotes a parallel lightning arrestor connected between a pair of bushings 39 at both ends of the combined switchgear, and is connected between upper terminals of the pair of bushings 39 attached to the tank. Reference numeral 30a denotes a first line unit, and 30b denotes a second line unit, each of which comprises a main bus-side disconnector 35, a circuit breaker 33, a line-side disconnector 36, a line arrester 37, and a parallel arrester 38.

The parallel lightning arrester 38 is of a zinc oxide type in which zinc oxide elements are stacked and accommodated in a porcelain tube, and its limit voltage is set to be about twice the limit voltage of the line lightning arrester 7.

Also in this configuration, in the power transmission lines 9a and 9b of the overhead transmission line 9, a multiple lightning strike occurs on the tower or the overhead ground line of the overhead transmission line 9 and a ground fault occurs in the overhead transmission line 9, and the line unit Even after the gas circuit breaker 33 of 30a or 30b interrupts the ground fault current, a lightning strike causes a ground fault, and a lightning surge intrudes into the opened gas circuit breaker 33 from a plurality of power transmission lines, and the line lightning arrester 37 between the poles. The lightning surge voltage that is three times the limiting voltage is applied, but the parallel lightning arrester 38 operates to prevent inter-electrode flashing of the gas circuit breaker 33 and protect the gas circuit breaker 33 from lightning surge caused by multiple lightning. Switchgear.

Embodiment 4 FIG. Embodiment 4 is an embodiment in which the parallel lightning arresters connected in parallel to the circuit breakers of Embodiments 1 to 3 are reduced in weight. FIG. 7 shows the configuration of the parallel lightning arrester.
In the figure, reference numeral 40 denotes a parallel lightning arrester, in which a stacked zinc oxide element 41 is inserted into the inner diameter portion of a resin insulator tube 42, and a lid 44 is attached to the end to seal the same, and a stable gas such as nitrogen gas is contained inside. The configuration is enclosed. The resin porcelain tube 42 has an FRP tube 42a formed in a cylindrical shape with a fiber reinforced resin at the inner diameter portion, an outer jacket 42b formed with a weather resistant resin and a fold 42c at the outer diameter portion at the outer periphery, and an outer jacket at the end. It is formed into a shape provided with a flange 43 integrally with 42b.

In the parallel lightning arrester 40 in which the circuit breaker is closed, no voltage is applied between the poles, and when the circuit breaker is opened, the pole between the main bus-side disconnector and the line-side disconnector is opened. Voltage is applied between them, the time is short, and the insulation is not exposed to severe conditions as compared with the insulator used between the ground, which is a favorable condition for aging.

When the parallel lightning arrester 40 has a configuration in which the zinc oxide element 41 is inserted into the resin insulator tube 42, the weight is greatly reduced, the assembling is facilitated, the mechanical strength of the switchgear is improved, and the weight can be reduced. .

Embodiment 5 FIG. The fifth embodiment is directed to a gas-insulated switchgear in which a main bus and a track unit of a switchgear of an electric substation are accommodated in a tank. This is an embodiment in which is not caused. FIG. 8 is a single-line diagram of a line unit portion of the switchgear for an electric substation according to the fifth embodiment, and FIG. 9 is a side view when the portion shown in FIG. 8 is a gas-insulated switchgear. In the figure, 51 is a main bus, 53 is a gas circuit breaker, 53c is an operating device of the gas circuit breaker 53, 54 is a current transformer, 55 is a main bus side disconnector, 56 is a line side disconnector, 57 is a line arrester, 5
Reference numeral 8 denotes a parallel lightning arrester, which is directly connected to the gas circuit breaker 53. 59 is a bushing connected to the overhead transmission line,
It is attached to the bushing tank 59a. 59b
Is a bushing tank mount.

Reference numeral 56a denotes a connection bus between the line disconnecting switch 56 and the bushing tank 59a, and 57a denotes a line arrestor mount. 50a is a first line unit and 50b is a second line unit.
4. The main bus-side disconnector 55, the line-side disconnector 56, and the line lightning arrester 57, and the parallel lightning arrester 58 is directly connected to the tank of the circuit breaker 53, and each device is accommodated and connected to the tank. The end of the bushing 59 is connected to the power transmission lines 9a and 9b of the overhead power transmission line 9.

The parallel lightning arrester 58 has a configuration in which zinc oxide elements are stacked and mounted next to the circuit breaker 53 accommodated in the tank and connected in parallel.
It is set to double before and after.

In this configuration, as in the first to third embodiments, the power transmission lines 9a and 9b of the overhead transmission line 9
Multiple lightning strikes on the tower or the overhead ground line of the overhead transmission line 9 and a ground fault occurs in the overhead transmission line 9 and the line unit 5
Even after the gas circuit breaker 53 of 0a or 50b is interrupted by the ground fault current, a lightning strike causes a ground fault of the overhead power transmission line, and a lightning surge intrudes into the opened gas circuit breaker 53 from a plurality of power transmission lines. A surge voltage three times the limit voltage of the line lightning arrester 57 is applied between the poles, but the parallel lightning arrester 58 operates and the gas circuit breaker 5
3 is prevented, and the switchgear of an electric station is protected from lightning surge caused by multiple lightning.

As described above, in the gas insulated switchgear in which the main bus 51, the first line unit 50a, and the second line unit 50b are accommodated in the tank, the parallel installation of the parallel lightning arrester 58 to the gas circuit breaker 53 allows the installation area to be increased. Can be configured without making it too large.

Embodiment 6 FIG. Embodiment 6 has a configuration in which the parallel lightning arresters of the single line diagram of FIG. 8 are arranged inside the circuit breaker.
FIG. 10 is a side view of the switchgear, and FIG. 1 is a cross-sectional view of the gas circuit breaker.
It is shown in FIG. In the figure, a main bus 51, a current transformer 54, a main bus-side disconnector 55, a line-side disconnector 56, a line arrester 57, and a bushing 59 are the same as those in FIGS. 8 and 9 of the fifth embodiment. 63 is a gas circuit breaker, 63a is a shutoff section, 6
3b is an insulating support member for insulatingly supporting the blocking portion 63a, 63
c is an operation mechanism, 63d is an insulating operation rod, and 63e is an opening and closing mechanism. The parallel lightning arrester 68 has a configuration in which zinc oxide elements 68a are stacked and arranged beside the cut-off portion 63a, and are connected in parallel to the cut-off portion 63a. The limiting voltage is set to about twice that of the line lightning arrester 57.

Also in this configuration, the first to third and fifth embodiments
Similarly to the above, in the transmission lines 9a and 9b of the overhead transmission line 9, a multiple lightning strike occurs on the tower or the overhead ground line of the overhead transmission line 9 and a ground fault occurs in the overhead transmission line 9 to shut off gas in the line unit. Even after the circuit breaker 63 cuts off the ground fault current, the gas circuit breaker 6 is opened due to the lightning strike and the ground fault of the overhead transmission line.
3, a surge voltage of three times the limit voltage of the line lightning arrester 57 applied between the poles is applied, and the parallel lightning arrester 68 operates to cause a flashover between the gas circuit breakers 63. It is a switchgear for electric stations that is prevented and protected from lightning surges caused by multiple lightning.

In this configuration, the parallel lightning arrester 68 is connected to the circuit breaker 6
By disposing the lightning arrester 3 inside, the space for arranging the parallel lightning arresters becomes unnecessary, and the tank of the circuit breaker 63 does not become too large.

[0043]

According to a first aspect of the present invention, there is provided a switchgear for an electric substation, wherein a main bus and at least a circuit breaker are arranged, one is connected to the main bus, and the other is connected to a transmission line of an overhead transmission line. A parallel lightning arrestor in which zinc oxide elements are stacked in series was connected in parallel to the breaker of the circuit breaker of the line unit, and multiple lightning strikes occurred on the overhead transmission line, and a ground fault occurred on the overhead transmission line. Even after the line unit circuit breaker cuts off the ground fault current, the lightning surge voltage from the multiple transmission lines goes around and the lightning surge voltage, which is three times the limit voltage of the line surge arrester applied between the circuit breaker electrodes due to the lightning surge voltage, is paralleled. The lightning arrester operates to prevent inter-electron flashover of the circuit breaker, thus providing a switchgear for an electric substation protected from lightning surge due to multiple lightning.

According to a second aspect of the present invention, there is provided a switchgear for an electric substation, wherein the circuit breaker according to the first aspect of the present invention is configured such that a circuit breaker is housed in a tank whose grounding portion is grounded and connected to both ends of the tank externally. A bushing is installed, a tank-type gas circuit breaker filled with insulating gas inside the tank, a parallel lightning arrestor is a lightning arrester containing stacked zinc oxide elements in an insulator tube, and a pair of tank-type gas circuit breakers. Since the configuration is connected between the upper ends of the bushings, the simple configuration of simply connecting parallel lightning arresters between the ends of the bushing when the conventional configuration is a tank type gas circuit breaker allows lightning strikes due to multiple lightning. A switchgear for an electric station in which no flashover between poles of the tank type gas circuit breaker occurs even in the case of receiving the electric power can be obtained.

According to a third aspect of the present invention, there is provided a switchgear for an electric substation, wherein the circuit breaker according to the first aspect is provided with a breaking portion in which an arc-extinguishing chamber and a switching electrode are accommodated in a porcelain tube, and a support for supporting the breaking portion. An insulator type gas circuit breaker composed of an insulator and a parallel lightning arrestor is a lightning arrestor that contains stacked zinc oxide elements in an insulator tube, and is arranged parallel to the interrupter of the insulator type gas circuit breaker and parallel to the interrupter. Since the connection configuration is used, if the conventional configuration is an insulator type gas circuit breaker, it is a simple configuration that simply connects a parallel lightning arrester instead of a voltage dividing capacitor arranged in parallel with the circuit breaker. Therefore, it is possible to configure a switchgear of an electric station in which the inter-electrode flash of the insulator type gas circuit breaker does not occur even in the case of receiving the electric shock.

According to a fourth aspect of the present invention, there is provided a switchgear for an electric substation, wherein a main bus and at least a circuit breaker are connected and housed in a tank, and a pair of bushings are attached to both ends of the tank. The busbar is connected, and the other bushing is stacked between the ends of the bushings attached to both ends of the tank of the switchgear of an electric substation with a plurality of line units connected to the transmission line of the overhead power transmission line. Since the zinc element was connected to parallel lightning arresters housed in the insulator tube, even after multiple lightning strikes on the overhead power transmission line and ground fault current was interrupted, the electrodes of the circuit breaker were wrapped around from multiple transmission lines. The parallel lightning arrester operates in response to a lightning surge three times the limit voltage of the line lightning arrester interposed therebetween, thereby preventing inter-electrode flashing of the circuit breaker. In addition, the existing switchgear has a simple configuration in which only a parallel lightning arrestor is connected between the ends of the bushing. There can be no switchgear for electric stations.

According to a fifth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the parallel lightning arrester having the structure according to any one of the second to fourth aspects is a resin insulator tube formed of a weather-resistant resin in a shape having a plurality of folds on an outer periphery. Furthermore, since the stacked zinc oxide elements are accommodated, the weight of the parallel lightning arrester is greatly reduced, the assembly is facilitated, and the mechanical strength of the switchgear is improved.

According to a sixth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the main bus accommodated in a grounded tank and at least a circuit breaker are connected and accommodated in a grounded tank,
An electric line comprising a plurality of line units each having one end connected to the main bus, a line lightning arrester arranged between the other end and the ground, and the other end connected to an overhead power transmission line via a bushing attached to the tank end; A zinc oxide element was stacked on the circuit breaker of the switchgear at the place and a parallel lightning arrestor housed in a grounded tank was connected in parallel with the circuit breaker, so there was a multiple lightning strike on the overhead transmission line and the overhead transmission line Even after a ground fault occurs and the circuit breaker of the line unit cuts off the ground fault current, the sneak from multiple transmission lines causes a lightning surge voltage between the electrodes of the circuit breaker that is three times the limit voltage of the line arrester. In addition, the parallel lightning arrester prevents inter-electrode flashes of the circuit breaker, and a configuration protected from lightning surge due to multiple lightning can be configured without increasing the installation area much.

According to a seventh aspect of the present invention, there is provided a switchgear for an electric substation, wherein the parallel lightning arrester according to the sixth aspect has a structure in which zinc oxide elements are stacked, connected in parallel to a circuit breaker, and arranged in a circuit breaker tank. Therefore, a space for arranging the parallel lightning arresters becomes unnecessary, the tank of the circuit breaker does not become too large, and the configuration in which the parallel lightning arresters are connected can be installed in substantially the same area as the conventional configuration.

According to an eighth aspect of the present invention, there is provided a switchgear for an electric substation, wherein the limiting voltage of the parallel lightning arrester connected in parallel with the interrupting unit according to any one of the first to seventh aspects is applied to the line arrester arranged on the line side. The limit voltage is set to be about twice as large as that of the above, so that even if a lightning surge voltage exceeding the withstand voltage between poles of the circuit breaker is applied, the flashlight between poles can be prevented by the parallel lightning arrester.

[Brief description of the drawings]

FIG. 1 is a single-line diagram of a line unit according to a first embodiment.

FIG. 2 is a side view of the case where the circuit breaker of the line unit shown in the single-line diagram of FIG. 1 is a tank-type gas circuit breaker.

FIG. 3 is a single-line diagram of a line unit according to a second embodiment.

4 is a side view of the case where the circuit breaker of the line unit shown in the single line diagram of FIG. 3 is an insulator type gas circuit breaker.

FIG. 5 is a single-line diagram of a line unit according to a third embodiment.

6 is a side view of a case where the line unit portion of the single line diagram of FIG. 5 is constituted by a composite gas insulated switchgear.

FIG. 7 is a configuration diagram of a parallel lightning arrester in which a zinc oxide element is accommodated in a resin insulator tube.

FIG. 8 is a single-line diagram of a line unit according to a fourth embodiment.

9 is a side view of a case where the configuration of the single line diagram of FIG. 8 is configured by a gas insulated switchgear.

FIG. 10 is a sectional view of a gas circuit breaker according to a fifth embodiment.

FIG. 11 is a sectional view of a configuration in which a parallel lightning arrester is incorporated in a tank of a circuit breaker of a switchgear for an electric substation according to a sixth embodiment.

FIG. 12 is a single-line diagram of a track unit of a conventional switchgear for an electric substation.

FIG. 13 is a side view of the conventional electric substation switchgear when the configuration of the single-line diagram of FIG. 12 is configured by air-insulated equipment.

[Explanation of symbols]

1 Main Bus, 4 Current Transformer, 5 Main Bus Side Disconnector, 6 Line Disconnector, 7 Line Arrestor, 9 Overhead Transmission Line, 9a
1st power transmission line, 9b 2nd power transmission line, 10a 1st line unit, 10b 2nd line unit, 13
Tank type gas circuit breaker, 18 parallel lightning arresters, 20a first line unit, 20b second line unit, 23
Insulator type gas circuit breaker, 28 parallel lightning arrester, 30a first line unit, 30b second line unit, 33
Gas circuit breaker, 34 Current transformer, 35 Main bus side disconnector, 3
6 line side disconnector, 37 line lightning arrester, 38 parallel lightning arrester, 39 bushing, 40 parallel lightning arrester, 41 zinc oxide element, 42 resin insulator, 43 flange, 44
Lid, 50a first line unit, 50b second line unit, 51 main bus, 53 gas circuit breaker, 54 current transformer, 55 main bus side disconnector, 56 line side disconnector, 5
7 Track lightning arrester, 58 parallel lightning arrester, 59 bushing, 63 gas circuit breaker, 63a blocking part, 63b insulating support member, 63c operating mechanism, 63d insulating operating rod, 63e opening and closing mechanism, 63T tank, 68 parallel lightning arrester, 68a zinc oxide element.

Continued on the front page (72) Inventor Masaki Hiratsuka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 5G016 CE02

Claims (8)

[Claims] 1. A main bus and at least a circuit breaker are connected, one is connected to the main bus, the other is connected to a power transmission line of an overhead power transmission line, and a line arrester is arranged between a connection portion with the power transmission line and the ground. An electric station switchgear comprising a plurality of line units, wherein a parallel lightning arrester having a zinc oxide element laminated thereon is connected in parallel to the circuit breaker. 2. The circuit breaker is a tank-type gas circuit breaker in which a breaker is housed in a tank whose ground is grounded, and a pair of bushings externally connected to both ends of the tank are attached, and the parallel lightning arresters are stacked. 2. The switchgear for an electric substation according to claim 1, wherein the zinc oxide element is housed in an insulator tube and connected between upper terminals of a pair of bushings of the circuit breaker. 3. The circuit breaker is an insulator type gas circuit breaker comprising a breaking part in which an arc-extinguishing chamber and a switching electrode are accommodated in a porcelain tube, and a supporting insulator part supporting the breaking part. 2. The electric substation according to claim 1, wherein a zinc oxide element stacked in the insulator tube is accommodated in the insulator type gas circuit breaker and arranged in parallel with the interrupter and connected in parallel to the interrupter. Switchgear. 4. A main bus and at least a circuit breaker are connected and housed in a tank, a pair of bushings are attached to both ends of the tank, one bushing is connected to the main bus, and the other bushing is connected to an overhead transmission line. In a switchgear for an electric substation having a plurality of line units connected to a power transmission line, a parallel lightning arrestor in which a stacked zinc oxide element is accommodated in an insulator tube is connected between upper terminals of the pair of bushings. A switchgear for an electric substation, characterized in that: 5. The parallel lightning arrester has a structure in which laminated zinc oxide elements are housed in a resin insulator tube formed of weather-resistant resin in a shape having a plurality of folds on an outer periphery. An electric station switchgear according to any one of claims 2 to 4. 6. A tank housed in a grounded tank connected to at least a circuit breaker and housed in a grounded tank, one end connected to the main bus, and grounded between the other end and ground. In a switchgear of an electric substation, a line arrester housed in the tank is disposed, and a plurality of line units connected to the overhead power transmission line via a bushing whose other end is attached to a tank end. A switchgear for an electric substation, wherein parallel lightning arresters housed in a stacked and grounded tank are connected in parallel to a circuit breaker. 7. The switchgear for an electric substation according to claim 6, wherein the parallel lightning arresters are stacked in a zinc oxide element, connected in parallel to a circuit breaker of the circuit breaker, and arranged in a circuit breaker tank. . 8. The limiting voltage of the parallel lightning arrester connected in parallel to the cutoff unit is set to be about twice the limiting voltage of the line arrester arranged on the line side.
The switchgear for an electric substation according to claim 7.