JPH07322440A - Phase changer for on-site testing of power cable lines - Google Patents

Abstract

(57) [Summary] [Structure] In the grounding case 31, the power cable line side 3
Cable line side electrode 33a to which the phase-phase cable 19 is connected
33c and the power-apparatus-side electrodes 35a to 35c to which the power-applying device-side power supply cable 23 is connected are arranged to face each other. Conductive rods 55a to 55c are slidably attached to the electrodes of the power-applying device, and insulating rods 57a to 57c for moving the conductive rods forward and backward from the outside of the ground case 31 are attached to the rear ends of the conductive rods.
Connect. The grounding case 31 has a cable line side electrode 33a.
Grounding devices 39a to 39c capable of individually grounding 33c to 33c are provided. [Effect] It is not necessary to assemble the cable terminal connection box when switching phases. Phase switching can be performed efficiently and reliably. It greatly contributes to shortening the time of on-site testing and cost reduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable line field test phase switching device used for a completion test of a power cable line.

[0002]

[Prior Art] As a completion test of a power cable line,
Due to the capacity of the voltage applying device and the test space, a withstand voltage test is usually performed with a DC voltage. Further, in recent years, an AC withstanding voltage test is being conducted while using a partial discharge test together, and a test using a waveform such as a damped oscillatory wave or an ultra-low frequency is being studied.

The power cable line has three phases per line, but when it becomes a long-distance line, due to the limitation of the capacity of the power supply device,
Further, in order to confirm the soundness of each phase, a test is often performed for each phase. In this case, when the test of one phase is completed, it is necessary to perform phase switching so that the test of the next phase can be performed. Phase switching is a simple operation when the terminal part of the power cable line and the live part of the charging device are exposed to the air, or when the test is conducted outdoors where there is no restriction on the distance from the surroundings. This can be done relatively easily by simply reconnecting the electrical leads.

However, in recent years, with the downsizing of substations and the like, the terminal portion of the power cable line is often of the SF ₆ gas-insulated equipment direct connection type or transformer direct connection type. In the case of such a device direct connection type, since the high voltage lead wire is sealed in the grounding case of the device, it is difficult to perform phase switching from the outside.

For this reason, conventionally, phase switching is performed as shown in FIG. In FIG. 6, 11 is the laid power cable line, and 13 is the terminal end thereof. The terminal portion 13 is directly connected to a GIS (gas insulated switchgear) 15. One end of a test cable 19 is connected to the terminal end 13 of the power cable line via an adapter 17 for each phase. The other end of the test cable 19 is connected to a power supply device 25 via a three-phase branch device 21 and a power supply cable 23 for each phase.

Now, assuming that a U-phase voltage application test is performed,
Connect the other end of the U-phase test cable 19 to the U of the three-phase branch device 21.
It is connected to the phase terminal connection box 21u, and the other end of the other two-phase (V-phase, W-phase) test cables 19 is connected to the ground conductor 27 and grounded. A blind plug 29 is inserted into the V-phase terminal connection box 21v and the W-phase terminal connection box 21w of the three-phase branching device 21 to seal them.
In this state, the U-phase voltage application test is performed.

When the V-phase test is performed after the U-phase test is completed, the phases are switched in the following procedure. First, the U-phase cable end portion of the three-phase branch device 21 is disassembled, a blind plug is inserted into the U-phase terminal connection box 21u, and the conductor of the pulled-out U-phase test cable 19 is grounded. Next, pull out the blind plug 29 from the V-phase terminal connection box 21v, and connect the V-phase test cable 19
The end portion of is connected to the V-phase terminal connection box 21v of the three-phase branching device 21, and the terminal connection box is assembled. This completes the phase switching work. The time required for this work is at most 2-3
It takes about time, and there is no particular problem if the V-phase test can be carried out immediately thereafter.

[0008]

However, the connection structure of the test cable to the terminal junction box of each phase of the three-phase branch device is similar to that of the prefabricated joint, in that the rubber stress cone is converted into the epoxy insulator and the cable insulator by the compression device. It is a structure that secures electrical characteristics by pressing and applying surface pressure to the insulator interface. Therefore, it takes time until the stress of the rubber stress cone is relaxed and the surface pressure at the interface becomes uniform (until predetermined electrical characteristics are obtained). It is the same that time is required for the stress relaxation of the rubber stress cone even in the part where the blind plug is inserted.

It is usually recommended that the voltage be applied after leaving it for one day with a sufficient margin. For this reason, even if the time of the voltage application test is 10 minutes per phase, the next phase can be tested on the next day, and the test can be performed only at the interval of one phase per day, and the efficiency of the test is strong. It was wanted.

In view of the above problems, an object of the present invention is to provide a phase switching device for efficiently performing a field test of a power cable line in a short time.

[0011]

A phase switching device for on-site testing of a power cable line according to the present invention has three cable line side electrodes and three power supply device side electrodes in a grounding case.
Three parallel cable lines are arranged so as to face each other in a one-to-one relationship, and three cable line side electrodes are connected to three-phase cable terminals on the power cable line side, respectively. The three electrodes on the side of the power-supplying device are electrically connected to each other so that they can be collectively connected to the device on the side of the power-supplying device. A conductive rod having a child is attached so as to be slidable in the axial direction, and an insulating rod for advancing and retracting the conductive rod from outside the grounding case is connected to the rear end of each conductive rod. The case is provided with a grounding device capable of individually grounding the three cable line side electrodes (Claim 1).

In the phase switching device of the present invention, three cable line side electrodes and three power supply device side electrodes are respectively arranged at 120 ° intervals around the central axis of the grounding case, and the power supply device side cable is provided. It is desirable that the terminal connection box and the high-voltage shield electrode at the tip thereof are arranged on the central axis of the grounding case (claim 2).

[0013]

When performing a field test of a power cable line using this phase switching device, first, the three cable line side electrodes are respectively connected to the three phase cable ends on the power cable line side, and they are electrically connected to each other. One cable on the side of the power-applying device is connected to the three electrodes on the side of the power-applying device connected to. A rubber stress cone is used for each cable terminal connection box as before, but all the connection boxes are assembled first, so the time required for stress relaxation of the rubber stress cone is 1
It only takes a batch.

After the time required for stress relaxation of the rubber stress cone has passed, for example, when performing a U-phase test, the U-phase cable line side electrode is ungrounded by a grounding device,
The V-phase and W-phase cable line side electrodes are grounded. Also, by operating the insulating rod, the U-phase conductive rod is moved forward,
The V-phase and W-phase conductive rods are retracted. This makes U
Conduct the electrical connection between the power-supply side electrode of the phase and the cable line side electrode,
Insulate the V-phase and W-phase voltage-applying device side electrodes and the cable line side electrodes. In this state, the output of the charging device is applied and the U-phase test is performed.

When the V-phase test is conducted next, the V-phase cable line side electrodes are made ungrounded by the grounding device, and the U-phase and W-phase cable line side electrodes are grounded. In addition, by operating the insulating rod, the V-phase conductive rod is moved forward, the U-phase and W-phase conductive rods are moved backward, and only the V-phase is connected to the power supply device. In this state, the output of the voltage applying device is applied and the V phase test is performed. At this time, since the time required for stress relaxation of the rubber stress cone has already passed, the test can be performed immediately.

When the W-phase test is carried out next, the test can be carried out immediately by connecting only the W-phase to the non-grounded power supply device by the same operation as described above.

The operation of the grounding device and the insulating rod may be manual or automatic, and may be set to either one in consideration of safety and reliability. In the case of automatic operation, the grounding device and the insulating rod are automatically driven by hydraulic pressure, etc., and the completion of grounding or switching is detected by a limit switch etc. It is also possible to apply sequence power supply by sequentially applying power to each phase and conducting a test.

According to the structure of claim 2, since the cable terminal connection box on the side of the power-applying device does not project in the radial direction, the maximum radial size of the device can be reduced.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 3 show an embodiment of a phase switching device for on-site testing of a power cable line according to the present invention. In the figure, 31 is a cylindrical grounding case in which SF ₆ gas is filled. In the grounding case 31, three cable line side electrodes 33a to 33c are provided around the center axis of the grounding case 31.
They are arranged at 0 ° intervals. Also, the cable line side electrode 33
a to 33c are separated from each other by a predetermined insulation distance in the axial direction, the three power-apparatus-side electrodes 35a to 35c are in one-to-one correspondence with the three cable line-side electrodes 33a to 33c on the same axis.
Are arranged so as to face each other. Electrodes 33a-33c, 35
All of a to 35c are high-voltage shield electrodes.

The cable line side electrodes 33a to 33c are provided at the tips of the cable terminal connection boxes 37a to 37c, respectively. The cable terminal connection boxes 37a to 37c are open at one end side of the grounding case 31, and there are 3 on the power cable line side.
The phase test cable 19 is connected.

Further, on the outer circumference of the grounding case 31, grounding devices 39a to 39c are provided corresponding to the cable line side electrodes 33a to 33c. Each of the grounding devices 39a to 39c has grounding rods 41a to 41c that can move forward and backward toward the cable line side electrodes 33a to 33c (in FIG. 1, 39c and 41c are on the back side). can not see). The cable line side electrodes 33a to 33c are provided with recesses 43 into which the tips of the ground rods 41a to 41c are fitted.

On the other hand, the three charging device side electrodes 35a to 35c are electrically connected to each other by a three-pronged conductor 45. Further, a cylindrical branch case 47 is projectingly provided on the outer peripheral portion of the grounding case 31 corresponding to one of the power-applying device side electrodes 35a. In this branch case 47, a cable terminal connection box 49 having a high-voltage shield electrode 48 at its tip is provided. The cable terminal connection box 49 is opened at the outer end side of the branch case 47, and the power charging cable 23 connected to the power charging device is connected thereto. The high-voltage shield electrode 48 at the tip of the cable terminal connection box 49 is connected to one power-apparatus-device-side electrode 35a by a conductor 51. As a result, the three power-charging device side electrodes 35a to 35c are collectively connected to the power-charging device.

Conductive rods 55a to 35c each having a male contactor 53 at its tip are attached to the three electrodes 35a to 35c on the side of the power-applying device.
55c is attached so as to be slidable in the axial direction.
Further, insulating rods 57a to 57c extending to the outside of the ground case 31 are connected to the rear ends of the conductive rods 55a to 55c, respectively. Each of the insulating rods 57a to 57c is held by a guide device 59 provided at the end of the ground case 31 and is movable in the axial direction. By operating the insulating rods 57a to 57c from the outside of the grounding case 31, the conductive rods
55a to 55c can be moved forward and backward.

In FIG. 2, the conductive rod 55a advances and the ground rod
41a is retracted, and FIG. 3 shows a state in which the conductive rod 55a is retracted and the ground rod 41a is advanced. Conductive rod 55
When a is advanced, as shown in FIG. 2, the male contact 53 at the tip of the a is fitted into the female contact 61 of the cable line side electrode 33a,
The voltage application device side electrode 35a and the cable line side electrode 33a are electrically connected, and the cable line side electrode 33a is not grounded. When the conductive rod 55a is retracted,
As shown in FIG. 3, the male contactor 53 at the tip of the conductive rod 55a is retracted into the power-apparatus-side electrode 35a, so that the power-apparatus-side electrode 35a.
a and the cable line side electrode 33a are electrically insulated, and the cable line side electrode 33a is grounded. Although only one phase is shown in FIGS. 2 and 3, other phases are the same.

The above is the configuration of the phase switching device 63 of this embodiment. Next, an on-site test method for a power cable line using the phase switching device 63 will be described with reference to FIG. 4, the same parts as those in FIGS. 1 to 3 are designated by the same reference numerals.
The terminal end 13 of the power cable line 11 to be tested is directly connected to a GIS (gas insulated switchgear) 15. To perform the test, an adapter 17 is provided for each phase at the terminal end 13 of the power cable line.
One end of the test cable 19 is connected via the. The other ends of the test cables 19 are connected to the cable terminal connection boxes 37a to 37c of the phase switching device 63, respectively. Also a phase switching device
The power-supplying device is installed in the cable terminal connection box 49 of the power-supplying device 25 of 63
The charging cable 23 extending from 25 is connected.

In this state, the time required for stress relaxation of the rubber stress cone of each cable terminal connection box is set. When the U-phase test is to be performed first after that time has passed,
Operate 41a-41c to V-phase and W-phase cable line side electrodes
33b and 33c are grounded, and the U-phase cable line side electrode 33a is ungrounded. Also, operate the insulating rods 57a to 57c to make U
The phase conductive rod 55a is advanced, and the V-phase and W-phase conductive rods 55b, 55c are retracted. As a result, the U-phase voltage-apparatus-side electrode 35a and the cable line-side electrode 33a become conductive, and V
The phase-apparatus-side electrodes 35b and 35c of the W-phase and the cable-line-side electrodes 33b and 33c are insulated. In this state, the output of the power supply device 25 is applied and the U-phase test is performed.

Next, when performing the V phase test, the ground rod 41
a is retracted and 41b is advanced (41c remains retracted)
At the same time, the conductive rod 57a is retracted and 57b is advanced (57c remains retracted). As a result, the cable line side electrodes 33a and 33c are grounded and 33b is not grounded, and the V-phase power-apparatus-side electrode 35b and the cable line-side electrode 33b are electrically connected, and the U-phase power-apparatus-side electrode 35a and the cable line Side electrode 33
a is insulated (W-phase 33c and 35c remain insulated). In this state, the output of the power supply device 25 is applied and the V-phase test is performed. At this time, since the time required for stress relaxation of the rubber stress cone has already passed, the test can be performed immediately.

Next, when performing the W-phase test, the ground rod 41
b is retracted and 41c is advanced (41a remains retracted)
At the same time, the conductive rod 57b is retracted and 57c is advanced (57a remains retracted). As a result, the cable line side electrodes 33a and 33b are grounded, 33c is not grounded, the W-phase power-apparatus-side electrode 35c and the cable line-side electrode 33c are electrically connected, and the V-phase power-apparatus-side electrode 35b and the cable line are connected. Side electrode 33
b is insulated (U-phase 33a and 35a remain insulated). In this state, the output of the power supply device 25 is applied and the W-phase test is performed. At this time as well, since the time required for stress relaxation of the rubber stress cone has already passed, the test can be performed immediately.

FIG. 5 shows another embodiment of the present invention. This phase switching device 63 is different from that shown in FIG.
Of the cable terminal connection box 49 for connecting the ends of the high-voltage shield electrode 48 and the high-voltage shield electrode 48 at the tip thereof are arranged on the central axis of the grounding case 31, and the high-voltage shield electrode 48 and each of the power-apparatus-device-side electrodes 35a to
35c is connected by the conductors 51 arranged in a radial pattern. Since the configuration other than the above is the same as that of the above-described embodiment and the method of use is also the same, the same reference numerals are given to the same portions and the description thereof will be omitted. The configuration shown in FIG. 5 has an advantage that the maximum radial dimension of the device can be reduced.

Next, AC of one line of 275 kV CV cable line
Table 1 shows the comparison results of the working time when the withstand voltage test was performed using the phase switching device of the present invention and when using the conventional three-phase branching device. The test is conducted in the order of U, V, and W phases, and the test conditions are 275 kV and 10 minutes. As is clear from Table 1, when the phase switching device of the present invention is used, the working time can be shortened significantly.

[0031]

[Table 1]

The device of the present invention is not limited to the conventional DC withstand voltage test of the line, but is also being put into practical use in recent years. It can be applied to any applied waveform, such as a test using a damped oscillatory wave that may occur.

[0033]

As described above, according to the present invention, the phase switching in the field test of the power cable line can be efficiently and reliably performed, which greatly contributes to the time reduction and cost reduction of the field test. be able to. Further, although skill is required for assembling the cable terminal, in the conventional device, it is necessary to arrange a skilled worker for each phase switching. Other than the above is phase switching work and does not require skill, so there is an advantage that there is a large degree of freedom in terms of placement of skilled workers.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a phase switching device of the present invention.

2 is a cross-sectional view showing a state where a conductive rod is advanced in the apparatus of FIG.

FIG. 3 is a cross-sectional view showing a state where the conductive rod is retracted in the device of FIG.

FIG. 4 is an explanatory diagram showing an on-site test method of a power cable line using the apparatus of FIG.

FIG. 5 is a partially cutaway perspective view showing another embodiment of the phase switching device of the present invention.

FIG. 6 is an explanatory diagram showing a conventional power cable line field test method using a three-phase branch device.

[Explanation of symbols]

11: Power cable line 13: Termination of power cable line 11 15: GIS (gas insulated switchgear) 17: Adapter 19: Test cable 23: Power distribution cable 25: Power distribution device 31: Grounding case 33a to 33c: Cable Line side electrodes 35a-35
c: Power supply device side electrodes 37a to 37c: Cable terminal connection box 39a to 39
c: Grounding devices 41a to 41c are grounding rods 47: Branch case 49: Cable terminal connection box 53: Male contacts 55a to 55c: Conductive rods 57a to 57
c: Insulating rod 59: Guide device 61: Female contact 63: Phase switching device

Claims (2)

[Claims] 1. A grounding case (31) having three cable line-side electrodes (33a to 33c) and three power-apparatus-side electrodes (35a to 33c).
35c) are arranged so as to face each other in a one-to-one relationship on the three parallel axes, and the three cable line side electrodes (33a to 33c) respectively have three phases on the power cable line (11) side. The terminal of the cable (19) is connected, and the three electrodes (35a to 35c) on the power-applying device side are electrically connected to each other and collectively connected to the power-applying device (25). Each of the three electrodes (35a to 35c) on the side of the power-applying device has a conductive rod (55) having a contact (53) with the other electrode at the tip.
a to 55c) are attached so as to be slidable in the axial direction, and the conductive rods (55a to 55c) are advanced from the outside of the grounding case (31) to the rear ends of the conductive rods (55a to 55c),
Insulating rods (57a-57c) to be retracted are connected to the grounding case (31).
33c) Grounding device (39a-
39c) is provided, The phase switching device for on-site testing of power cable lines. 2. Cable line side electrodes (33a to 33c)
And the three electrodes (35a to 35c) on the side of the power-applying device are arranged at 120 ° intervals around the central axis of the grounding case (31), respectively, and are connected to the cable terminal connection box (49) on the side of the power-supplying device (25) The phase switching device for on-site testing of a power cable line according to claim 1, characterized in that the high-voltage shield electrode (48) at its tip is arranged on the central axis of the grounding case (31).