JP2000011823A - Insulated operation support bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the unbalance of resistivity and exhibit excellent dielectric strength. SOLUTION: A coating layer 6 consisting of chromium oxide is applied to the surface of an insulated bar 1. Since the resistivity of this coating layer 6 is sufficiently low, the current passing through a fiber group which readily carries a current is easily transferred to the coating layer 6, and uniformly distributed. Accordingly, the state where charges are accumulated in the end part of the fiber group never occurs, the disturbance of electric field distribution by charging nor occurs, and the dielectric strength to DC voltage can be significantly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating operation support rod used for a high-voltage switchgear such as a gas circuit breaker.

[0002]

2. Description of the Related Art In general, high-voltage switchgears are
Sufficient insulation must be provided between the electrically charged and ground potential parts to allow mechanical movement. For this reason, an insulating operating rod is used in a high-voltage switchgear. For example, when an insulating operating rod is used for a circuit breaker, the insulating operating rod receives a large impact load when the circuit breaker is turned on and off. Therefore, the impact strength of the insulating operating rod must be sufficiently high. At the same time,
Since a high voltage is always applied to both ends of the insulated operating rod, a sufficient electric strength is required. In particular, a DC voltage may be applied to general AC equipment. For this reason, sufficient consideration must be given to the dielectric strength against direct current. Also, when supporting electrically charged parts,
Insulating support rods are used, but it is indispensable for such insulating support rods to similarly support a heavy object, withstand large mechanical stresses, and to secure a sufficient electrical strength in electrical terms.

As this kind of insulating operation supporting rod, for example, a rod in which a joint member 2 made of metal is fitted to an end of an insulating rod 1 made of fiber reinforced resin as shown in FIG. 5 has been proposed. In this insulating operation supporting rod, a screw structure 3 is provided at a fitting portion between the insulating rod 1 and the joint member 2 and tightened, and an adhesive material 4 such as epoxy resin is applied to the fitting portion to form the screw structure 3. It does not come loose. The surface of the insulating rod 1 is provided with a powder coating layer 5. The powder coating layer 5 is obtained by adding a mixed curing agent and an inorganic filler such as alumina to the solid epoxy resin as main components.
The fiber-reinforced resin (more specifically, glass fibers in the fiber-reinforced resin) is prevented from deteriorating due to the decomposition gas of sulfur hexafluoride, which is an insulating gas, covering the insulating rod 1.

[0004]

However, the above-mentioned conventional insulating operation supporting rod has the following problems.
That is, while the resistivity of the epoxy adhesive 4 or the powder coating layer 5 is on the order of 10 ¹⁵ Ω · cm,
The resistivity of the fiber reinforced resin constituting the insulating rod 1 is 10 ¹⁴ Ω ·
It was an order of magnitude lower on the order of cm. Further, the resistivity of the fiber reinforced resin is not uniformly distributed, and the resistance is low in the longitudinal direction of the fiber and is higher by about one digit in the direction perpendicular to the longitudinal direction. Such an unbalance in the resistivity of the insulating operation supporting rod greatly affects the insulation strength against high-voltage insulation, particularly DC voltage. Specifically, the following three points have been problems.

(1) Charging on the surface of the insulating rod 1. The electric current flowing through the fiber reinforced resin is likely to flow in the longitudinal direction of the fiber, and there is a group of fibers particularly easy to flow the electric current. Therefore, the resistivity of the insulating rod 1 is not uniform. When such a fiber group that easily flows a current is interrupted on the surface of the insulating rod 1, that is, when the end of the fiber group that easily flows a current is on the surface of the insulating rod 1, the current flowing through the fiber group is It is blocked by the powder coating layer 5 having a resistivity higher by one digit or more. As a result, a large amount of electric charge is accumulated in the portion of the powder coating layer 5 and charging occurs. This disturbs the electric field distribution,
The dielectric strength has been greatly reduced.

(2) Charging of the fitting portion between the insulating rod 1 and the joint member 2 Similarly to (1), when the fiber group through which the current easily flows is interrupted at the fitting portion between the insulating rod 1 and the joint member 2, that is, when the end portion of the fiber group through which the current easily flows is in the fitting portion, The current flowing through the fiber group is blocked by the epoxy-based adhesive 4 having a higher resistivity by one digit or more. As a result, a large amount of electric charge is accumulated in the adhesive material 4 and charging occurs. As a result, a large potential difference was generated between the insulating rod 1 and the joint member 2 made of a metal material, and the dielectric strength was greatly reduced.

(3) Peeling of the epoxy adhesive 4 due to mechanical stress applied to the insulating operation supporting rod. The insulating operation support rod is always subjected to a large mechanical stress, and a mechanical stress is applied to a fitting portion between the insulating rod 1 and the joint member 2. Although the fitting portion is not mechanically disengaged by the screw structure 3, the microscopic peeling of the epoxy-based adhesive 4 from an electrical viewpoint
The contact resistance in this area may be even higher.
In this case, the charging of the fitting portion between the insulating rod 1 and the joint member 2 described in the preceding paragraph (2) was further accelerated, and the dielectric strength was greatly reduced.

By the way, not all insulating rods 1 include a fiber group through which an electric current is particularly easy to flow.
In fact, it is very rare. Therefore, if there is a special insulating rod 1 that includes a fiber group that is particularly easy to flow an electric current, it is common to find out and eliminate it by a shipping test. In this case, it is important that the withstand voltage characteristic of the insulating operation supporting rod does not change from the time of the shipping test. However,
Insulated operation rods often receive large impact loads,
There is a possibility that a mechanical stress is applied to change the electrical connection state of the fitting portion between the insulating rod 1 and the joint member 2, in other words, the electrical resistance between the two from the shipping test at the factory. Therefore, conventionally, there has been a demand for an insulating operation support rod in which the withstand voltage characteristics do not change from the time of the shipping test even when a mechanical stress is applied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and a main object of the present invention is to provide an insulating operation supporting rod capable of exhibiting an excellent dielectric strength without an imbalance in resistivity. It is in.

It is another object of the present invention to provide an insulating operation support rod whose withstand voltage characteristics do not change from the time of a shipping test even when subjected to mechanical stress.

[0011]

In order to achieve the above object, the invention of claim 1 is characterized in that chromium oxide is applied to the surface of a rod-shaped insulator. The invention according to claim 2 is characterized in that chromium oxide is mixed with powder for coating, and this powder is applied to the surface of a rod-shaped insulator. Further, the invention of claim 3 is characterized in that BTA (benzotriazole) is uniformly mixed in a small amount with a powder for coating, and this powder is applied to the surface of a rod-shaped insulator.

The first, second and third aspects of the present invention are as follows.
Since the insulation rod surface is coated with low resistance,
A large amount of electric charge is not accumulated on the surface of the insulating rod, so that charging can be suppressed. That is, according to the first aspect of the present invention, the resistivity is 1.3 × 10 ³ Ω · cm, which is as low as that of a semiconductor and has an SF 6 resistance.
By applying chromium oxide, which has excellent decomposition gas performance, to the surface of the insulating rod, the resistivity of the insulating rod is uniformly reduced, regardless of whether there is a fiber group on the surface of the insulating rod that is easy to conduct current, and SF6 decomposition gas resistance can be improved. In addition, in the invention of claim 2, by mixing chromium oxide into the powder for coating, it is possible to lower the resistivity of the powder so as to approach the resistivity of the insulating rod itself. The unbalance of the resistivity can be eliminated.

BTA mixed with powder according to the invention of claim 3
(Benzotriazole) has been widely used since it was introduced in Japan around 1972 because of its non-toxicity in the fields of antifreeze, photography, and paints. It is well known that the flow electrification between oil and insulating oil is dramatically suppressed. According to the third aspect of the present invention, by utilizing such properties of BTA (benzotriazole), charging of the surface of the insulating rod is suppressed.

A fourth aspect of the present invention is characterized in that chromium oxide is mixed with an epoxy-based adhesive, and the end of the insulator and the joint member are bonded by the adhesive. The invention according to claim 5 is characterized in that BTA (benzotriazole) is uniformly mixed in a small amount with an epoxy-based adhesive, and the end of the insulator and the joint member are bonded by the adhesive. In claim 4 and claim 5 of the present invention as described above, since the low-resistance adhesive is applied to the insulating rod and the joint member, even if the end portion of the fiber group through which the current easily flows is located in the fitting portion. Thus, there is no large difference from the resistivity of the adhesive. Therefore, the resistivity of the fitting portion between the insulating rod and the joint member becomes uniform, and it is possible to prevent the occurrence of charging in the adhesive material portion.

The invention according to claim 6 is characterized in that the joint member is divided into a joint portion receiving mechanical stress and an electrode portion for electrical connection. In such a case, only the joint portion receives the mechanical force, and the electrode portion side does not receive the mechanical force. Therefore, even if the insulating operation supporting rod receives a mechanical force, the electric resistance between the insulating rod and the electrode portion does not change, and the withstand voltage characteristic of the insulating operating supporting rod does not change from the time of the shipping test.

The invention according to claim 7 is characterized in that the electrode portion of the joint member is bonded to the insulator end portion with an adhesive obtained by mixing chromium oxide with an epoxy adhesive. The invention according to claim 8 is characterized in that the electrode portion of the joint member is similarly bonded to the end of the insulator with an adhesive obtained by uniformly mixing a small amount of BTA (benzotriazole) with an epoxy adhesive. According to the seventh and eighth aspects of the present invention, by using a low-resistance adhesive to fix the insulating rod and the electrode portion, it is possible to prevent the occurrence of charging between the insulating rod and the electrode portion.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The same members as those in the conventional example shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted.

(1) First Embodiment [Configuration] FIG. 1 shows a first embodiment of the present invention.
(Corresponding) is a longitudinal sectional view of the insulating operation support rod. The first embodiment is different from the above-mentioned prior art embodiment shown in FIG. 5 in that a coating layer 6 applied for the purpose of protecting the fiber reinforced resin constituting the insulating rod 1 from sulfur hexafluoride decomposition gas.
The present invention relates to a technology for reducing the resistance of a substrate. In the first embodiment, the six coating layers are made of chromium oxide.

[Operation] Next, the operation of the first embodiment will be described. Chromium oxide has a resistivity of 1.3 × 10 ³
It is as low as a semiconductor of Ω · cm and excellent in SF6 decomposition gas resistance. Therefore, by applying a liquid epoxy resin containing about 60% of chromium oxide to the insulating rod 1 by brush or spray, the resistivity of the insulating rod 1 becomes 10 ¹¹ Ω · cm.
Thus, the SF6 decomposition gas resistance can be improved.

[Effects] Even if the fiber group through which the current easily flows is interrupted on the surface of the insulating rod 1, the resistivity of the coating layer 6 is sufficiently low on the surface of the insulating rod 1, so that the fiber group through which the current easily flows flows. The incoming current easily moves to the coating layer 6 and becomes evenly distributed. Therefore,
The situation where charges are accumulated at the ends of the fiber group does not occur, the electric field distribution is not disturbed by the charging, and the dielectric strength against DC voltage can be greatly improved.

[Modification of the First Embodiment] As an embodiment corresponding to the second embodiment, a part or all of the inorganic filler such as alumina in the conventional powder coating layer 5 is partially or entirely oxidized. This material may be used as the coating layer 6 instead of chromium. For example, if the chromium oxide content is 60%, the resistivity of the coating layer 6 of this powder can be reduced to 10 ¹¹ Ω · cm.

According to an embodiment of the present invention, a small amount of BTA (benzotriazole) is added to a powder for powder coating mainly composed of an epoxy resin, a mixed hardener and an inorganic filler such as alumina. May be uniformly mixed, and this may be used as the coating 6 layers. Expressing the charge-suppressing effect of BTA (benzotriazole) on the scale of the resistivity of the coating layer 6, the resistivity of this powder is reduced by mixing BTA (benzotriazole) into an epoxy resin in an amount of about 1 to 3%. It can be reduced to 10 ¹⁴ Ω · cm.

(2) Second Embodiment [Structure] FIG. 2 shows a second embodiment of the present invention.
(Corresponding) is a longitudinal sectional view of the insulating operation support rod. The second embodiment is characterized in that a low resistance adhesive 7 is applied to a fitting portion between the insulating rod 1 and the joint member 2. The low-resistance adhesive 7 is formed by mixing a small amount of chromium oxide with an epoxy-based adhesive. In the case of the embodiment corresponding to claim 5, the low-resistance adhesive 7 is formed by mixing a small amount of BTA (benzotriazole) with an epoxy-based adhesive instead of chromium oxide.

[Operation] As described in the operation of the first embodiment, compounds such as chromium oxide and BTA (benzotriazole) are mixed with other organic chemical materials to greatly reduce the resistivity. Can be. For example, when about 60% of chromium oxide is mixed with an epoxy-based adhesive, its resistivity drops to 10 ¹¹ Ω · cm. Meanwhile, BTA
When about 1 to 3% of (benzotriazole) is mixed in the epoxy adhesive, its resistivity can be reduced to 10 ¹⁴ Ω · cm.

[Effect] Even when a fiber group through which an electric current easily flows is interrupted at the fitting portion between the insulating rod 1 and the joint member 2 made of a metal material, the fiber group is applied to the fitting portion between the insulating rod 1 and the joint member 2. Since the resistivity of the adhesive 7 is sufficiently low, particularly the current flowing through the fiber group through which the current easily flows easily transfers to the adhesive 7 and finally is absorbed by the joint part 2 made of a metal material. Is done. Therefore, a situation in which electric charges are accumulated at the end of the fiber group does not occur, a large potential difference does not occur between the insulating rod 1 and the joint part 2, and the dielectric strength against DC voltage is greatly increased. It is possible to improve.

(3) Third Embodiment [Configuration] FIG. 3 is a longitudinal sectional view of an insulating operation support rod according to a third embodiment of the present invention (corresponding to claims 6 and 7). Third
The feature of this embodiment resides in that the joint member 2 is divided into a joint portion 2 'for handling mechanical stress and an electrode portion 8 for treating electrical insulation. In the third embodiment, the joint portion 2 ′ and the electrode portion 8 are fixed to the insulating rod 1 by:
This is performed by using a low-resistance adhesive 7 mixed with chromium oxide. The joint 2 'and the electrode component 8 are electrically connected by a flexible metal member (not shown).

[Operation] In the third embodiment having the above configuration, all mechanical stress applied to the insulating operation support rod is processed by the joint 2 ', and no mechanical stress is applied to the electrode portion 8. Therefore, the fixed state of the electrode portion 8 and the insulating bar 1 does not change. That is, the state of the electrical connection of the electrode component 8 to the insulating rod 1, that is, the electrical resistance between the two does not change from the time of the shipping test at the factory.

[Effect] According to the third embodiment, the electrical connection between the electrode portion 8 and the insulating rod 1 does not change, and the electric connection between the joint 2 'and the insulating rod 1 is not changed. Even if the connection state changes, the withstand voltage characteristic of the insulating operation supporting rod does not change because the electrode portion 8 functions as a shield electrode. Therefore, once the abnormal lot is eliminated by the withstand voltage test, the dielectric strength does not change thereafter, so that screening by the withstand voltage test at the time of shipment is sufficient. In addition, in the third embodiment, the bonding of the electrode portion 8 is performed by the low-resistance adhesive 7 mixed with chromium oxide, so that the number of insulating operation supporting rods that are shaken off by screening is reduced, and
Yield improves. In an embodiment corresponding to claim 8, the adhesive 7 uses BTA (benzotriazole) instead of chromium oxide.

[Modification of Third Embodiment] As a third embodiment, as shown in FIG. 4, the insulating rod 1 is thickened on the front surface of the electrode portion 8, and the insulating rod 1 is thickened. The contacted portion is in contact with the front surface of the electrode portion 8 and is bonded by the epoxy adhesive 4. The joint 2 ′ and the electrode 8 are electrically connected by a metal spring 9.

In such an embodiment, the area where the electrode portion 8 contacts the insulating rod 1 can be increased. Therefore, the screening yield can be improved. In particular, since the direction of the fibers of the insulating rod 1 is generally set in the axial direction of the insulating rod 1, the electrode portion 8 may have a contact surface in a direction perpendicular to the axial direction of the insulating rod 1. This is effective for effectively flowing the current flowing in the fiber direction into the electrode portion 8, and from this point also, the effect of improving the yield of screening by the shipping test becomes large.

[0031]

As described above, according to the present invention,
By applying a low-resistance coating to the insulating rod surface,
An insulating operation supporting rod capable of exhibiting an excellent dielectric strength without an imbalance in resistivity was provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention, and is a cross-sectional view of an insulating operation support rod.

FIG. 2 is a sectional view of an insulating operation support rod according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention, and is a cross-sectional view of an insulating operation support rod.

FIG. 4 is a configuration diagram of a modification of the third embodiment of the present invention, and is a cross-sectional view of an insulating operation support rod.

FIG. 5 is a sectional view showing a configuration of a conventional insulating operation support rod.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating rod 2 ... Joint member 3 ... Screw structure 4 ... Epoxy-based adhesive 5 ... Powder coating layer 6 ... Coating layer 7 ... Low resistance adhesive 8 ... Electrode parts 9 ... Metal spring

Claims (8)

[Claims] 1. An insulating operation supporting rod, wherein chromium oxide is applied to the surface of a rod-shaped insulator. 2. A chromium oxide is mixed with a powder for coating,
An insulating operation supporting rod, wherein the powder is applied to a surface of a rod-shaped insulator. 3. An insulating operation supporting rod, wherein BTA (benzotriazole) is uniformly mixed with a small amount of powder for coating, and the powder is applied to the surface of a rod-shaped insulator. 4. An insulating operation support rod in which a rod-shaped insulator is provided, and an end of the insulator is fitted with a joint member made of metal, wherein chromium oxide is mixed with an epoxy-based adhesive. An insulating operation support rod, wherein an end portion of the insulator and the joint member are adhered to each other. 5. An insulating operation support rod in which a rod-shaped insulator is provided, and a joint member made of metal is fitted to an end of the insulator, wherein BTA (benzotriazole) is uniformly applied to the epoxy-based adhesive. Characterized in that an end of the insulator and the joint member are adhered to each other by the adhesive. 6. An insulating operation supporting rod in which a rod-shaped insulator is provided, and a joint member made of metal is fitted to an end of the insulator, wherein the joint member holds a mechanical stress. And an electrode portion for maintaining electrical connection. 7. The insulating operation support rod according to claim 6, wherein the electrode portion is bonded to an end of the insulator by an adhesive obtained by mixing chromium oxide with an epoxy adhesive. 8. The method according to claim 1, wherein the electrode portion is made of BTA with epoxy adhesive.
7. The insulating operation support rod according to claim 6, wherein said insulating operation supporting rod is adhered to an end of said insulator by an adhesive in which a small amount of (benzotriazole) is uniformly mixed.