JP2013070449A - Sealed switchgear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the insulation reliability of an insulation section part for a long time by preventing the deterioration of voltage-withstanding performance in the insulation section part which is caused by external contamination while suppressing high-frequency high voltage occurring in the insulation section part.SOLUTION: A through hole 25 is formed at an insulation part 10 of an insulation spacer 17 so as to be arranged parallel with the axial direction of a closed vessel 3. A discharge prevention element 14, formed by a resistive element or a lightning arrester element, is attached to the interior of the through hole 25.

Description

  Embodiments of the present invention relate to a hermetic switchgear provided with an insulating section at the connection between hermetic containers.

  Generally, in a switchgear, a hermetic switchgear in which a high voltage conductor is insulated and supported in a hermetic container is arranged. Among them, those provided with an insulating section at the connection part between the sealed containers ensure high insulation reliability because AC induction current does not flow through the sealed container even when a plurality of sealed containers are connected. .

  For example, as shown in FIG. 8, in a closed type switchgear including a disconnector 5, a plurality of closed containers 3 are connected and arranged. A high voltage conductor 1 is insulated and supported inside the sealed container 3 and an insulating gas 2 is enclosed. In such a hermetic switchgear, an insulating section 11 having an insulating portion 10 such as epoxy is provided at the connecting portion between the hermetic containers 3.

  As the structure of the insulating portion 10 of the insulating section 11, the following two structures are typical. One is a structure in which the outer edge portion of the insulating spacer 17 installed in the hermetic container 3 is used as it is as the insulating portion 10 for the insulating section as shown in FIG. The other is a structure using a ring-shaped thin insulating plate 18 as the insulating portion 10 as shown in FIG. The insulating plate 18 is generally used in combination with a metal flange 19. 9 and 10, reference numeral 23 denotes an insulating washer, and reference numeral 24 denotes a bolt / nut.

  In the hermetic switchgear having the insulating section 11 as described above, the insulating section 10 of the insulating section 11 insulates the hermetic container 3 even if an AC current flows through the high voltage conductor 1. For this reason, a closed loop circuit associated with a plurality of ground points is not formed, and an AC induced current flowing in the sealed container 3 can be suppressed. Therefore, the temperature rise of the sealed container 3 can be avoided, and the insulating performance of the insulating gas 2 sealed in the sealed container 3 is not lowered.

  Incidentally, in the hermetic switch shown in FIG. 8, a discharge 13 may occur in the insulating portion 10 of the insulating section 11. Here, the generation process of the discharge 13 will be described with reference to FIGS. 8, 11, and 12. As shown in FIG. 11, when the high voltage circuit of the hermetic switchgear is composed of a high voltage circuit 6 between the circuit breaker 4 and the disconnecting switch 5 and a power supply side high voltage circuit 7. Assume that the disconnecting switch 5 is opened while the circuit breaker 4 is open.

  At this time, since the potential difference between the high voltage circuit 6 and the power supply side high voltage circuit 7 changes, an interelectrode discharge 8 occurs between the electrodes of the disconnector 5. As a result, the voltage of the high voltage circuit 6 between the circuit breaker 4 and the disconnect circuit 5 suddenly changes so as to coincide with the voltage of the power supply side high voltage circuit 7, and 10 MHz is applied to the high voltage circuit of the sealed switchgear. A super high frequency transient voltage 9 is generated (see the graph of FIG. 12).

  When the high-frequency transient voltage 9 is generated, a high-frequency high voltage 12 (shown in FIG. 8) is induced between the sealed containers 3 that are insulated by the insulating section 11. The high frequency high voltage 12 disappears in a very short time of several microseconds. However, if the voltage value is higher than the withstand voltage in the insulating section 11, a discharge 13 is generated in the insulating section 10 of the insulating section 11.

  Since the high frequency high voltage 12 applied to the insulating section 11 is generated each time the high voltage circuit is opened and closed, the discharge 13 generated in the insulating section 10 may be repeated many times. Therefore, the discharge 13 not only causes an inductive failure to the adjacent control circuit, but may damage the insulating portion 10.

  If the damage of the insulating part 10 due to the discharge 13 is increased, the insulating performance of the insulating section 11 is lowered, and an AC induction current flows through the sealed container 3, leading to an increase in the temperature of the sealed container 3. Therefore, preventing damage to the insulating portion 10 due to the discharge 13 in the insulating section 11 is a very important point for improving reliability even when viewed from the whole of the hermetic switchgear.

  As a specific conventional example for preventing the discharge 13 from occurring, the techniques shown in FIGS. 13 and 14 are known. In the conventional example of FIG. 13, a resistance element 14 is attached between the sealed containers 3 that are separated from each other (for example, Patent Document 1). The resistance element 14 can reduce the high frequency high voltage 12 applied to the insulating section 11.

  Further, in the conventional example shown in FIG. 14, a gap type lightning arrester element 15 is attached in parallel to the insulator 10 of the insulating section 11 (for example, Patent Document 2). The lightning arrester element 15 includes a discharge electrode 15a, and when the high frequency high voltage 12 is applied, the discharge electrode 15a discharges to prevent the discharge 13 from being generated.

  The elements 14 and 15 shown in FIGS. 13 and 14 can effectively reduce the voltage value of the high-frequency high voltage 12, so there is a concern that the voltage value of the high-frequency high voltage 12 exceeds the insulation withstand voltage of the insulating section 11. No. As a result, the generation of the discharge 13 in the insulating portion 10 can be reliably prevented. In addition, when the high frequency high voltage 12 is generated, a current flows through the elements 14 and 15 to the sealed container 3. It does not affect the temperature rise.

JP-A 61-167313 Japanese Patent No. 2672665

  However, the following problems have been pointed out in the above prior art. That is, in the conventional example of FIGS. 13 and 14, the resistance element 14 and the lightning arrester element 15 are attached to the outside of the insulating section 11, that is, the outside of the sealed container 3. Therefore, the length of the mounting conductor of each of the elements 14 and 15 becomes long, and the circuit inductance 16 (shown in FIGS. 13 and 14) including the elements 14 and 15 tends to be large. This is because the conductor composing the electric circuit has an inductance proportional to the length.

  The impedance of the circuit inductance 16 due to the attached conductor length is larger than the impedance of the elements 14 and 15 with respect to the high-frequency voltage 12 exceeding 10 MHz. For this reason, the elements 14 and 15 cannot effectively reduce the high-frequency high voltage 12, and even if the elements 14 and 15 are installed, the generation of the discharge 13 in the insulating portion 10 may not be sufficiently prevented.

  Further, in the conventional example of FIGS. 13 and 14, since the elements 14 and 15 are located outside the insulating section 11, these elements 14 and 15 have a problem that they are easily affected by contamination. If the elements 14 and 15 are soiled, it cannot be denied that the withstand voltage characteristics of the elements 14 and 15 are deteriorated. Furthermore, if the degree of contamination progresses and the withstand voltage values of the elements 14 and 15 are significantly reduced, even the withstand voltage performance against the AC induced current that flows during normal AC voltage operation is in danger. For this reason, the contamination of the elements 14 and 15 has been a serious problem.

  As described above, in the conventional hermetic switchgear, since the element for preventing discharge at the insulating section is installed outside the hermetic container, the mounting conductor of the element becomes longer and the impedance is increased, and the high frequency transient It has been difficult to reduce the voltage. In addition, by installing an element for preventing discharge on the outside of the sealed container, the element tends to be deteriorated in withstand voltage performance due to the influence of fouling, and there is a risk that dielectric breakdown may occur in the insulating part of the insulating section. there were. As a result, in the conventional hermetic switchgear, it has been difficult to maintain the insulation reliability for a long time.

  The hermetic switchgear according to the embodiment is proposed in order to solve the above problems. In this embodiment, in a closed type switchgear in which an insulating section is provided at the connection between the sealed containers, the withstand voltage performance of the insulating section due to external contamination is reduced while suppressing high frequency high voltage generated in the insulating section. The purpose of this is to maintain the insulation reliability of the insulation section for a long period of time.

  In order to achieve the above object, an embodiment provides an element that prevents discharge from occurring in an insulating section inside the insulating section in a hermetic switchgear in which an insulating section is provided at the connection between the sealed containers. It is characterized by having been attached.

The principal part sectional view of a 1st embodiment. Sectional drawing of the principal part of the modification of 1st Embodiment. The principal part sectional view of a 2nd embodiment. (A) is sectional drawing of the connection conductor of 2nd Embodiment, (B) is sectional drawing of the discharge prevention element of 2nd Embodiment. The principal part sectional view of a 3rd embodiment. Sectional drawing of the principal part of 4th Embodiment. Explanatory drawing which shows the Vi characteristic of the nonlinear resistance insulation board in 4th Embodiment. Sectional drawing of the conventional closed type switchgear. Sectional drawing which shows the structure of the insulation division part of the conventional closed type switchgear. Sectional drawing which shows the structure of the insulation division part of the conventional closed type switchgear. The circuit block diagram of the conventional sealing type switchgear. Explanatory drawing of the high frequency transient voltage generate | occur | produced when the disconnecting switch is open-operated in the conventional hermetic switchgear. Sectional drawing of the conventional closed type switchgear provided with the discharge prevention element. Sectional drawing of the conventional closed type switchgear provided with the discharge gap.

  Hereinafter, a hermetic switchgear according to an embodiment will be described with reference to the drawings. In all of the following embodiments, an insulating section having an insulating portion is provided at the connecting portion between the sealed containers. Therefore, the same members as those in the conventional example shown in FIGS. 9 and 10 are denoted by the same reference numerals, and the description thereof is omitted.

(1) First Embodiment [Configuration]
As shown in FIG. 1, in the first embodiment, as in the example shown in FIG. 9, the outer edge portion of the insulating spacer 17 is used as the insulating portion 10 of the insulating section portion 11. The embodiment shown in FIG. 2 is a modification of the first embodiment. In the embodiment of FIG. 2, as in the example shown in FIG. 10, the insulating plate 18 </ b> A combined with the metal flange 19 is used as the insulating portion 10 of the insulating section 11. That is, the embodiment shown in FIG. 2 is obtained by applying this embodiment to the example shown in FIG.

  In such a 1st embodiment, the through-hole 25 is formed in the insulating part 10 of the outer edge part of the insulating spacer 17 in parallel with the axial direction of the airtight container 3. In the modification of the first embodiment, a through hole 25 is formed in the insulating plate 18A. Inside the through hole 25, a discharge preventing element 14 made of a resistance element or a lightning arrester element is attached. In the modification of the first embodiment shown in FIG. 2, the thickness of the insulating plate 18A is set to be thicker than that of the insulating plate 18 shown in FIG. .

[Function and effect]
In the first embodiment as described above, the discharge preventing element 14 is attached inside the through hole 25, that is, inside the insulator 10. Therefore, the circuit length of the discharge preventing element 14 can be significantly shortened as compared with the case where the discharge preventing element 14 is attached to the outside of the insulating section 11.

  Therefore, the inductance of the circuit including the discharge prevention element 14 becomes very small, and the discharge prevention element 14 can effectively exert a protection function against the high-frequency voltage 12 exceeding 10 MHz. That is, the discharge preventing element 14 can reduce the high frequency high voltage 12 applied to the insulating section 11, and can reliably prevent the discharge 13 from occurring in the insulating section 10.

  Further, since the discharge preventing element 14 disposed inside the insulating portion 10 is not exposed to the outside, it is not easily affected by external contamination. Therefore, the withstand voltage performance of the discharge preventing element 14 does not deteriorate due to contamination. As a result, the withstand voltage performance with respect to the high frequency high voltage 12 as well as the withstand voltage performance with respect to the AC induction current during normal operation can be maintained for a long period of time. Thereby, there is no fear that an insulation breakdown will occur in the insulating portion 10 of the insulating section 11, and the insulation reliability of the insulating section 11 can be maintained for a long period of time.

  Furthermore, the member including the insulating portion 10 is usually manufactured by casting, whether it is the insulating spacer 17 of the first embodiment or the insulating plate 18A of the modified example. Therefore, an appropriate through hole 25 can be easily provided in the insulating spacer 17 or the insulating plate 18A simply by adjusting the casting mold. Therefore, the work of assembling the discharge preventing element 14 into the insulating portion 10 can be efficiently advanced, and the hermetic switchgear can be quickly assembled.

(2) Second Embodiment [Configuration]
Next, a second embodiment will be described with reference to FIG. In the second embodiment, the insulating plate 18 combined with the metal flange 19 is used as the insulating portion 10 of the insulating section 11. In the second embodiment, through holes 25 are formed in both the insulating plate 18 and the metal flange 19. A connecting conductor 20 is installed in the through hole 25. The connection conductor 20 is fixed to the inner wall portion of the insulating section 11. The discharge prevention element 14 </ b> A is attached inside the through hole 25 so as to be sandwiched between the two connection conductors 20. The discharge prevention element 14 </ b> A is detachably installed on the connection conductor 20.

  As shown in FIG. 4A, the connection conductor 20 is provided with two cases 201 that overlap in the left-right direction, and a spring 202 having an elastic force in the left-right direction is accommodated in the case 201. The case 201 is adapted to expand and contract in the axial direction while receiving the elastic force of the spring 202. As shown in FIG. 4B, the discharge preventing element 14A is configured by covering an element portion 141 made of a resistance element or a lightning arrester element with an insulating mold 142 in contact with the metal flange 19.

[Function and effect]
The second embodiment having the above-described configuration has the following unique operational effects in addition to the operational effects of the first embodiment. The metal flange 19 is often manufactured by machining, but in the second embodiment, a through hole 25 is formed in the metal flange 19 that is such a machined product. Therefore, the size and position of the through hole 25 can be freely adjusted, and the attachment work of the discharge preventing element 14A to the insulating portion 10 can be further efficiently performed.

  In the second embodiment, since the through holes 25 are formed in both the insulating plate 18 and the metal flange 19, even if the insulating plate 18 has a thin ring shape as in the prior art, the mounting space for the discharge preventing element 14A is used. Can be secured. Therefore, unlike the first embodiment, it is not necessary to employ a thick insulating plate 18A, which is economical.

  Furthermore, in the second embodiment, since the case 201 expands and contracts, it is easy to attach and detach the discharge preventing element 14A to and from the connection conductor 20, and the workability of attaching the discharge preventing element 14A is good. In addition, since the insulating mold 142 covers the element portion 141 in the discharge preventing element 14A, even if the discharge preventing element 14A is located inside the metal flange 19, there is no fear that the discharge preventing element 14A is damaged.

(3) Third Embodiment [Configuration]
Next, a third embodiment will be described with reference to FIG. The third embodiment is an improved example of the second embodiment, and the upper part of the through hole 25 is opened up to the upper surface of the metal flange 19, and this opening part can take out the discharge preventing element 14A. An extraction port 26 is formed. A lid member 21 that closes the take-out port 26 is attached to the take-out port 26 so as to be freely opened and closed.

[Function and effect]
In the third embodiment, in addition to the functions and effects of the first and second embodiments, there are the following functions and effects. That is, since the outlet 26 is provided in the metal flange 19, the lid member 21 can be opened and the discharge preventing element 14 </ b> A inside the through hole 25 can be taken out from the outlet 26. Therefore, it is possible to easily inspect and replace the discharge prevention element 14A, and after assembling the switchgear, the number of discharge prevention elements 14A attached can be changed according to the generation state of the high-frequency voltage 12. Easy. Thereby, the insulation reliability of the insulation division part 11 further improves.

(4) Fourth Embodiment [Configuration]
As shown in FIG. 6, the fourth embodiment is characterized in that the insulating plate 18 combined with the metal flange 19 is a non-linear resistance insulating plate 22 made of a non-linear resistance resin. The dimension and shape of the nonlinear resistance insulating plate 22 are the same as those of the conventional insulating plate 18, and are different from the insulating plate 18 in that the nonlinear resistance insulating plate 22 is made of a nonlinear resistance resin filled with a nonlinear resistance material. Further, the non-linear resistance insulating plate 22 is waterproofed on the outer surface.

[Function and effect]
Since the non-linear resistance insulating plate 22 has non-linear resistance characteristics, the applied voltage to the insulating plate 22 is small during operation with only a normal AC voltage. Therefore, the non-linear resistance insulating plate 22 can maintain a very high resistance value due to non-linear resistance characteristics. Therefore, the resistance between the sealed containers 3 is increased, and the AC induced current can be reliably prevented from flowing through the sealed container 3.

  On the other hand, when the high-frequency high voltage 12 is generated by the operation of the disconnector 5, the voltage value applied to the insulating section 11 due to the non-linear resistance characteristic of the non-linear resistance insulating plate 22 becomes a relatively low limit voltage. Limited (see graph in FIG. 7). For this reason, it is possible to prevent dielectric breakdown from occurring in the insulating portion 10 of the insulating section 11.

  Further, since the non-linear resistance insulating plate 22 is manufactured by casting a resin, it is easy to manufacture the nonlinear resistance insulating plate 22 in a shape that is thinly cast and has a wide contact area with the metal flange 19. As a result, the circuit length of the circuit connecting the sealed containers 3 via the non-linear resistance insulating plate 22 can be shortened, and the circuit inductance is reduced. Therefore, the voltage applied to the insulating section 11 can be effectively limited even for the high-frequency voltage 12 exceeding 10 MHz, and there is no possibility that the discharge 13 is generated in the insulating section 10.

  Furthermore, in the fourth embodiment, the outer surface of the non-linear resistance insulating plate 22 is waterproofed so that it is not easily affected by external contamination, and long-term insulation reliability is easily secured. For this reason, it is possible to reliably prevent the discharge 13 from being generated in the insulating portion 10 of the insulating section 11 with respect to the high-frequency voltage 12. Thereby, the insulation reliability of the insulation division part 11 required for prevention of AC induction current can be maintained for a long period of time in the airtight container 3.

(5) Other Embodiments In the present specification, a plurality of embodiments according to the present invention have been described. However, the above embodiments are presented as examples, and are intended to limit the scope of the invention. Not done. That is, the above-described embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention. For example, the discharge prevention element attached to the inside of the insulation section is not limited to a resistance element or a lightning arrester element, but can be appropriately selected as long as it is a surge protection element that reduces the high-frequency voltage applied to the insulation section. It is.

DESCRIPTION OF SYMBOLS 1 ... High voltage conductor 2 ... Insulating gas 3 ... Sealed container 4 ... Circuit breaker 5 ... Disconnector 6 ... High voltage circuit 7 between disconnector and circuit breaker ... Power supply side high voltage circuit 8 ... Interelectrode discharge 9 ... High frequency transient voltage 10 ... Insulating part 11 ... Insulating section 12 ... High frequency high voltage 13 ... Discharge 14, 14A ... Discharge prevention element 141 ... Element part 142 ... Insulating mold 15 ... Discharge gap 16 ... Inductance 17 ... Insulating spacers 18, 18A ... Insulating plate 19 ... Metal flange 20 ... Connecting conductor 21 ... Lid member 22 ... Non-linear resistance insulating plate 25 ... Through hole 26 ... Extraction port

Claims (6)

A plurality of sealed containers are connected, a high-voltage conductor is insulated and supported inside the sealed container, and an insulating section for insulating and separating the sealed containers is provided at a connection portion between the sealed containers. In switchgear,
An enclosed switchgear characterized in that an element for preventing discharge in the insulating section is attached inside the insulating section. An insulating spacer made of an insulating material is installed in the sealed container,
The insulating section is composed of an outer edge of the insulating spacer,
A through hole is formed in an outer edge portion of the insulating spacer serving as the insulating section,
The hermetic switchgear according to claim 1, wherein the discharge prevention element is attached to the through hole. The insulating section is provided with a metal flange and an insulating plate,
A through hole is formed in the insulating plate,
The hermetic switchgear according to claim 1, wherein the discharge prevention element is attached to the inside of the through hole. The insulating section is provided with a metal flange and an insulating plate,
A through hole is formed in the insulating plate and the metal flange,
The hermetic switchgear according to claim 1, wherein the discharge prevention element is attached to the inside of the through hole. The discharge prevention element is detachably attached to the inside of the through hole,
In the through hole, a discharge port for taking out the discharge prevention element to the outside of the through hole is inserted and formed,
The sealed opening / closing device according to claim 3 or 4, wherein a lid member that closes the extraction opening is attached to the extraction opening so as to be freely opened and closed. A plurality of sealed containers are connected, a high-voltage conductor is insulated and supported inside the sealed container, and an insulating section for insulating and separating the sealed containers is provided at a connection portion between the sealed containers. In switchgear,
The insulating section is provided with a metal flange and an insulating plate,
2. The hermetic switchgear according to claim 1, wherein the insulating plate is made of a non-linear resistance resin filled with a non-linear resistance material.

Images