JPH08241805A - Lightning arrester - Google Patents

Abstract

PURPOSE: To improve reliability of a thyristor valve by securing the stability and the vibration-resisting strength of the thyristor valve by accomplishing the space-saving of the thyristor valve, and by stabilizing the life of a resistor for a long term while the protection level of required dielectric breakdown is being satisfied. CONSTITUTION: A thyristor valve 1 is formed by laminating two valve units 1a and 1b, and among three valve arms 4, each valve unit is formed between two valve arms which are neighbouring with each other. Each valve arm is fixed by two insulative supporting poles. A plurality of thyristor elements 3 are series-connected on each valve unit between the neighbouring two valve arms, and a laminated unit 10, which is formed by laminating two lightning arrester unit, is arranged in parallel with the thyristor element 3. A characteristic element 13 is housed in the porcelain tube 12 of the lightning arrester unit 11, and a shield unit 14 is arranged on the circumference of the upper and the lower ends of the lightning arrester unit 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester, and more particularly to improvement of a lightning arrester provided for protecting a thyristor valve installed in a DC power transmission or frequency conversion station.

[0002]

2. Description of the Related Art Conventionally, in a DC power transmission system or a frequency conversion station, a thyristor valve for converting between AC and DC has been installed. The thyristor valve is configured to withstand a required high voltage and maintain a required current capacity by connecting a plurality of thyristor elements in series or in parallel. With a thyristor valve having such a configuration, there is a high possibility that dielectric breakdown will occur due to overvoltage such as lightning surge.Therefore, a lightning arrester for valve protection is installed in the arm portion of the thyristor valve to prevent dielectric breakdown of the thyristor valve. I am trying.

The lightning arrester for protecting the thyristor valve is
By connecting the non-linear resistor housed in the porcelain tube in series between the valve arms, the bus bar or terminal in the thyristor valve is connected to the ground, and the generated overvoltage is quickly released to the ground and the power transmission system. It has the function of shutting off the follow-up current continuously supplied from and recovering to the normal state. As such a lightning arrester for valve protection,
Conventionally, the one as shown in FIG. 5 is known.

In FIG. 5, the thyristor valve 1 is composed of four stages of valve units 1a to 1d stacked from the low pressure side to the high pressure side, and each of these valve units 1a to 1d includes a plurality of valve arms 4. Among them, it is configured between two valve arms adjacent to each other. The valve arms 4 are supported and fixed by a plurality of insulating columns 2.

A plurality of thyristor elements 3 are electrically connected in series between the two valve arms adjacent to each other for each valve unit, and four lightning arrester units 5a to 5d are connected to each other. Valve unit 1a
To 1d are electrically connected in parallel.

In each of the lightning arrester units 5a to 5d, a characteristic element formed by laminating a required number of nonlinear resistors having zinc oxide as a main component is housed in a porcelain insulator. Since such a lightning arrester using zinc oxide as a resistor generally has stable voltage-current characteristics,
While it is possible to effectively release the overvoltage while keeping the insulation breakdown protection level at a low level, it is always used with the operating voltage applied.Therefore, depending on the steady-state voltage applied to the arrester unit, the life may be shortened. Has the property of inviting.

The steady voltage applied to each arrester unit in the thyristor valve is different from the normal AC voltage, and changes depending on the installation position of each arrester unit in the thyristor valve. This is due to the rectification ripple generated by the switching of the thyristor valve and the commutation current superposed on the rectification ripple, which causes a difference in the voltage waveform and the peak value of the steady voltage for each arrester unit.

That is, as shown in FIG. 6, the voltage waveform 6a applied to the arrester unit 5a connected to the low pressure side valve unit 1a has a voltage waveform close to an AC half wave. Further, the voltage waveform 6 applied to the arrester unit 5b connected to the low pressure side valve unit 1b
The voltage b is similar to the DC waveform, and the voltage having the same peak value as that of the voltage waveform 6a is applied. On the other hand, the same can be said for the arrester units 5c and 5d connected to the valve units 1c and 1d on the high voltage side. However, on the high voltage side, the peak value of the voltage applied to each arrester unit is twice that on the low voltage side. (See applied voltage waveforms 6c and 6d).

From the characteristics of the resistor and the steady voltage as described above, conventionally, when the lightning arrester for protecting the thyristor valve is selected, the steady voltage applied to each valve unit and its waveform and peak value are The surge arrester with an appropriate level of insulation breakdown protection is selected after giving due consideration to the effect on the resistor of the surge arrester unit.

[0010]

However, the conventional lightning arrester described above has the following problems. First, in the conventional arrester configuration, only a single arrester unit is placed between each valve arm,
The height of the arrester unit determines the height of the valve arm.

Further, in recent years, the increase in the demand for electric power has led to a remarkable increase in the voltage and capacity of the power transmission system. Along with this, the size of the lightning arrester unit installed in the thyristor valve also increases, and The number of arrangements also tends to increase. As described above, as the surge arrester unit becomes larger, the height up to the valve arm at the upper end of the insulating strut will inevitably be set higher, and as a result, the scale of the thyristor valve will increase as a whole. It was

On the other hand, in the conventional arrester unit, the lower end thereof is only fixed to the lower valve arm of the two adjacent valve arms, and the upper end of the arrester unit is adjacent to each other. It was only electrically connected to the upper valve arm of the two valve arms. Therefore, when the weight of the lightning arrester unit arranged on the valve arm increases with the increase in size of the lightning arrester unit, there is also a problem that the stability of the thyristor valve is impaired and the seismic resistance of the thyristor valve decreases. .

Further, when a higher level of energy responsibility is required for the arrester for protecting the thyristor valve, it is necessary to arrange a plurality of arrester units in parallel between the valve arms. In addition, a lightning arrester for thyristor protection is required to have a low protection level. Since such a lightning arrester with a low protection level is applied at a high charge rate, a lightning arrester arranged between valve arms is used. It is necessary to make the potential distribution of the unit uniform.

However, when a plurality of lightning arrester units are arranged in parallel, there is a problem that the potential distribution of the lightning arrester units tends to become non-uniform due to the potential influence from the adjacent thyristor element. Therefore, conventionally, it has been necessary to devise the installation position of the lightning arrester unit in order to avoid this potential influence, and it has been difficult to secure the installation space.
In addition, when the arrester unit is applied to the valve unit on the high voltage side, a high ground potential is applied, which increases the charging current flowing in the ground capacitance, resulting in a more uneven potential distribution of the arrester unit. There was a problem of becoming.

As described above, in the conventional lightning arrester for protecting thyristor, not only a large installation space is required for installing the thyristor valve due to the increase in size of the lightning arrester unit, but also the seismic resistance of the thyristor valve is increased due to the increased weight of the lightning arrester unit. There was a fear that it would fall. Moreover, since it was difficult to arrange the arrester units in parallel while maintaining the uniform potential distribution of the arrester units, it was not possible to flexibly cope with higher energy responsibilities. Moreover, due to the potential effect from the thyristor element and the uneven distribution of the potential of each arrester unit due to the applied amount of the ground voltage, the wear of the resistor in the arrester unit progresses, which directly affects the life of the arrester. I was afraid.

The present invention has been made in view of the problems of the prior art as described above, and an object of the present invention is to secure seismic resistance of a thyristor valve and to save space, and to prevent required dielectric breakdown. While meeting the protection level,
It is an object of the present invention to provide a lightning arrester with long-term stability of the resistor and improved reliability.

More specifically, the first object of the present invention is to
To increase the number of lightning arrester units arranged in each valve unit, thereby configuring the thyristor valve with a smaller number of valve units and reducing the overall scale of the thyristor valve.

A second object of the present invention is to improve the resistance to the high energy duty in the arrester while maintaining the characteristics of the resistors in each arrester unit by making the potential distribution of the arrester unit uniform. is there.

A third object of the present invention is to equalize the potential distribution of the arrester unit arranged in the valve unit on the high voltage side in the vertical direction, thereby ensuring the reliability of the arrester regardless of the applied ground voltage. It is to secure.

A fourth object of the present invention is to further equalize the influence of the potential from the thyristor element in the horizontal direction of the lightning arrester and to make the potential distribution of the lightning arrester unit more uniform, thereby further improving the resistance of the lightning arrester to the energy duty. It is to improve.

A fifth object of the present invention is to integrate the thyristor valve and each arrester unit and to reduce the weight of the insulator tube of the arrester unit while ensuring sufficient protection so that the thyristor valve has a high seismic resistance. It is to improve.

[0022]

In order to solve the above problems in the prior art, the invention according to claim 1
A lightning arrester unit formed by housing a characteristic element made of a non-linear resistor in a porcelain insulator is a lightning arrester arranged between valve arms of a thyristor valve containing a plurality of thyristor elements. A stacking unit formed by vertically stacking a plurality of the lightning arrester units is arranged between two adjacent valve arms.

In a second aspect of the present invention, a lightning arrester unit in which a characteristic element made of a non-linear resistor is housed in a porcelain insulator is provided between the valve arms of a thyristor valve housing a plurality of thyristor elements. In each of the lightning arrester units, shield rings having the same diameter are respectively provided at upper and lower ends, and between the two valve arms adjacent to each other among the plurality of valve arms, the plurality of lightning arrester units are connected to the plurality of thyristors. It is characterized in that they are arranged in parallel so as to be parallel to the elements.

In a third aspect of the present invention, a lightning arrester unit is provided in which a characteristic element made of a non-linear resistor is housed in a porcelain tube, and the lightning arrester is arranged between valve arms of a thyristor valve housing a plurality of thyristor elements. In the plurality of valve arms, a plurality of stacked units formed by vertically stacking the lightning arrester units are arranged between two valve arms adjacent to each other, and the stacked units are the same at upper and lower ends of each lightning arrester unit. A plurality of shield rings each having a diameter are provided, and the plurality of laminated units are arranged in parallel so as to be parallel to the plurality of thyristor elements.

According to a fourth aspect of the present invention, in the lightning arrester according to any one of the second to third aspects, the shield ring provided at the upper end of each lightning arrester unit is It is arranged at a position lower than the upper end surface of the characteristic element, and the shield ring provided at the lower end portion of each lightning arrester unit is arranged at substantially the same height as the lower end surface of the characteristic element of each lightning arrester unit. Characterize.

According to a fifth aspect of the present invention, in the lightning arrester according to any one of the first to fourth aspects, the characteristic element has a columnar structure formed by laminating a plurality of nonlinear resistors. In addition, a plurality of characteristic elements having the columnar structure are housed in the porcelain tube in parallel so as to be parallel to the thyristor element.

According to a sixth aspect of the present invention, in the lightning arrester according to any one of the first to fifth aspects, the insulator tube is a heat-shrinkable tube around an insulating member made of fiber reinforced plastic. Configured by providing a strip-shaped covering member, the upper and lower end surfaces of the laminated unit or the arrester unit,
It is characterized in that it is fixed to valve arms located on both upper and lower sides thereof.

[0028]

The operation of the present invention having the above construction is as follows. First, according to the invention described in claim 1, instead of a single arrester unit, a laminated unit in which a plurality of arrester units are vertically stacked is arranged for each valve unit of the thyristor valve. Since the number of lightning arrester units arranged in each valve unit can be increased in this way, when arranging the same number of lightning arrester units, the thyristor valve can be configured with a smaller number of valve units. As a result, the height of the thyristor valve can be limited and its size can be reduced.

According to the second aspect of the invention, the shield rings arranged around the upper and lower ends of each lightning arrester unit are arranged in parallel with the thyristor element. This can prevent the influence of the potential from the thyristor element from spreading to the arrester unit. As a result, the potential distribution of the arrester unit becomes uniform, and it becomes easy to electrically connect the arrester units in parallel, so that it is possible to withstand a high energy duty. Moreover, since the shield rings are arranged at the upper and lower ends of each arrester unit, the same effect can be obtained even when the polarity is reversed.

According to the invention of claim 3, the size of the thyristor valve is reduced by the laminated unit, and the laminated unit is constituted by the shield rings provided at the upper and lower ends of the arresters forming the laminated unit. It is possible to make the electric potential distribution of the uniform. Therefore, the characteristics of the resistor can be stabilized and the life of the arrester in which the laminated unit is arranged can be extended.

According to the fourth aspect of the present invention, the upper end portion of each lightning arrester unit is lower than the upper end surface of the characteristic element, and the lower end portion of the lightning arrester unit is disposed at substantially the same height as the lower end surface of the characteristic element. By the shield ring
It is possible to guarantee the charging capacity that flows out to the electrostatic capacity due to the ground voltage. Therefore, a uniform potential distribution is obtained in the vertical direction, that is, in the vertical direction of the characteristic elements in the arrester unit, and even in the arrester unit arranged on the high voltage side, the characteristics of the resistor in the arrester unit are stable, The reliability can be maintained.

According to the fifth aspect of the present invention, in each lightning arrester unit, a plurality of columnar characteristic elements arranged in parallel in the porcelain insulator so as to be parallel to the thyristor element influence the influence of the potential from the thyristor element. Receive evenly. Therefore, the electric potential distribution of each arrester unit can be effectively made uniform along the juxtaposed direction of the characteristic elements. As a result, the characteristics of the resistor in each lightning arrester unit become more stable, and the resistance of the lightning arrester to the energy duty can be further improved.

According to the sixth aspect of the present invention, each lightning arrester unit has a significantly reduced weight due to the porcelain tube constituted by covering the insulating member made of fiber reinforced plastic with the heat shrinkable tube, and Adhesive and well protected. Further, the laminated unit is supported and fixed to the valve arm at the upper and lower ends to stabilize the thyristor valve. As a result, the seismic resistance of the thyristor valve can be improved.

[0034]

【Example】

(1) First Example An example to which the present invention is applied will be described below with reference to the drawings. First, a first embodiment to which the present invention is applied will be described with reference to FIG. FIG. 1 is a side view showing the internal structure of the thyristor valve in the first embodiment.

In FIG. 1, the thyristor valve 1 has two
One valve unit 1a and one valve unit 1b are stacked from the low pressure side to the high pressure side. Each of the valve units is configured between two valve arms of the three valve arms 4 that are adjacent to each other, and the valve arms 4 are supported and fixed by two insulating columns 2.

Here, between the two valve arms adjacent to each other, a plurality of thyristor elements 3 are connected in series for each valve unit, and two surge arrester units 11 for valve protection are vertically stacked. The laminated unit 10 is formed so as to be parallel to the thyristor element 3 (claims 1 and 3).

The insulator 12 of the lightning arrester unit 11
A characteristic element 13 formed by laminating a required number of nonlinear resistors containing zinc oxide as a main component is housed therein.

A shield ring 14 having the same diameter is arranged around the high pressure side and low voltage side ends of the lightning arrester unit 11. A plurality of the lightning arrester units 11 thus configured are arranged in parallel with the thyristor element 3 (claims 2 and 3).

The operation and effect obtained by the first embodiment configured as described above are as follows. First, the first
In the embodiment, the arrester unit 1 is provided for each valve unit.
Since the laminated unit 10 in which 1 is stacked in two stages is used, the number of valve units conventionally required to arrange the same number of arrester units can be reduced by half. As a result, the height of the thyristor valve 1 can be reduced. Therefore, it is possible to save the installation space of the thyristor valve 1 and to reduce the cost required for the installation (claims 1 and 3).

Further, since each lightning arrester unit 11 is arranged in parallel with the thyristor element 3 in each valve unit, the shield ring 14 provided around the upper and lower ends of each lightning arrester unit 11 has a lightning arrester unit 11. 1
The influence of the potential from the thyristor element 3 on 1 is made uniform. This makes it possible to eliminate the bias in the potential distribution, so that the lightning arrester unit 11 can be easily connected in parallel without considering the variation in the potential distribution.
As a result, it is possible to easily obtain the resistance to the high energy duty required in the lightning arrester for protecting the thyristor valve.

Further, in this way, the arrester unit 1
When the potential distribution of No. 1 is made uniform, a specific portion of the resistor is not consumed in the lightning arrester unit 11 even when it is applied at a high voltage application rate. Therefore, the characteristic of the resistor in the arrester unit 11 can be maintained in a stable state for a long time. That is, since the resistance to the energy duty can be strengthened while the protection level of insulation breakdown is kept low, the life of the arrester can be extended and the reliability thereof can be improved (claims 2 and 3).

Even when the thyristor valve 1 is reversed in polarity, the potential distribution can be made uniform by the shield ring arranged below, and the same effect as described above can be obtained.

(2) Second Embodiment A second embodiment to which the present invention is applied will be described below with reference to FIG. FIG. 2 is a cross-sectional view taken along the line AA ′ of the thyristor valve 1 shown in FIG.

As shown in FIG. 2, in the second embodiment, the first
In addition to the configuration of the embodiment, in particular, the characteristic element has a columnar structure characteristic element, that is, the characteristic element column 20 in which a required number of nonlinear resistors are laminated, so that the characteristic element column 20 is parallel to the thyristor element 3 in each valve unit. In addition, a plurality of them are juxtaposed in the porcelain bushing 12 (claim 5).

The operation and effect obtained by the second embodiment configured as described above are as follows. In the insulator tube 12 of the arrester unit 11, the thyristor element 3
The plurality of characteristic element columns 20 arranged in parallel so as to be parallel to
However, it is evenly affected by the potential from the thyristor element 3. That is, the potential distribution of the arrester unit 11 can be effectively made uniform by the plurality of characteristic element columns 20. As a result, the characteristics of the resistor in the lightning arrester unit 11 can be further stabilized, and it is possible to cope with the case where a higher energy duty is required for the lightning arrester.

(3) Third Embodiment A third embodiment to which the present invention is applied will be described below with reference to FIG. FIG. 3 is an enlarged view showing the position where the shield ring 14 is arranged at the upper and lower ends of the lightning arrester unit 11.

As shown in FIG. 3, in the third embodiment, the first
In addition to the configuration of the embodiment or the second embodiment, in particular, the shield ring 14a provided on the upper end portion of the lightning arrester unit 11, that is, on the high-voltage side is arranged at a height lower than the upper end surface of the characteristic element 13 of the lightning arrester unit 11. ing. Further, the shield ring 14b provided on the lower end portion of the lightning arrester unit 11, that is, on the low-pressure side is arranged at substantially the same height as the lower end surface of the characteristic element 13 of the lightning arrester unit 11 (claim 4).

The operation and effect obtained by the third embodiment configured as described above are as follows. That is,
Shield rings 14a and 1 are provided at the predetermined positions described above.
By arranging 4b respectively, the charging current flowing out to the electrostatic capacitance to the ground can be guaranteed, and a very uniform potential distribution can be obtained along the vertical direction of the characteristic element 13 in the arrester unit 11. Therefore, even in the arrester unit 11 arranged on the high voltage side, the characteristics of the resistor are stable, and the reliability of the arrester can be maintained.

(4) Fourth Embodiment A fourth embodiment to which the present invention is applied will be described below with reference to FIG. FIG. 4 is an enlarged view showing the structure of the porcelain bushing 12 in the arrester unit 11.

As shown in FIG. 4, in the fourth embodiment, the insulator tube 12 of the lightning arrester unit 11 forming the laminated unit 10 uses the insulating cylinder 40 made of fiber reinforced plastic as an insulating member, and the surface layer of the insulating cylinder 40. The whole is covered with a heat-shrinkable tubular covering member, that is, a heat-shrinkable tube 41. The heat-shrinkable tube 41 has a structure including a plurality of cap-shaped folds, which matches the shape of the insulating cylinder 40.

In FIG. 4, only the upper and lower ends of the plurality of cap-shaped folds are shown and the shape of the heat-shrinkable tube 41 is shown in a simplified form in order to simplify the notation. Actually, as shown by a chain double-dashed line portion in FIG. 4, a plurality of similar cap-shaped folds are continuously provided between the upper and lower end portions along the longitudinal direction of the insulating cylinder 40. It is assumed that

Further, the upper end and the lower end of the laminated unit 10 arranged between the two valve arms adjacent to each other are supported and fixed at the connecting portions 42a and 42b with these two valve arms ( Claim 6).

The operation and effect obtained by the fourth embodiment constructed as described above are as follows. That is,
Since the porcelain bushing 12 of the lightning arrester unit 11 uses fiber reinforced plastic, it is lighter in weight than the conventional porcelain porcelain bushing and is covered by the heat-shrinkable tube 41 having a cap portion. Sufficient protection and strength can be secured. Further, by the laminated unit 10 formed by stacking the lightning arrester units 11 as described above,
Since the two valve arms adjacent to each other can be fixed and supported together, the stability of the thyristor valve 1 is maintained,
Moreover, the seismic resistance of the thyristor valve 1 can be improved.

[0054]

As described above, according to the present invention, the space efficiency in the installation of the thyristor valve is improved, the stability and seismic resistance of the thyristor valve are improved, and the potential distribution of each arrester unit is improved. By making uniform, it is possible to provide a lightning arrester with enhanced reliability by enhancing resistance to energy duty while keeping the protection level of dielectric breakdown low.

[Brief description of drawings]

FIG. 1 is a side view showing an internal configuration of a thyristor valve 1 in which a lightning arrester according to a first embodiment of the present invention is arranged.

FIG. 2 is a lightning arrester unit 1 according to a second embodiment of the present invention.
It is a figure showing the arrangement | sequence of the characteristic element 13 in the porcelain insulator 12 of 1, and is an arrow sectional drawing of the AA 'direction in FIG.

FIG. 3 is a shield ring 1 according to a third embodiment of the present invention.
The enlarged view showing the arrangement position of FIG.

FIG. 4 is an enlarged view showing a configuration of a porcelain insulator tube 12 according to a fourth embodiment of the present invention.

FIG. 5 is a side view showing an internal configuration of a thyristor valve in which a conventional lightning arrester is arranged.

6 is an explanatory diagram showing a voltage waveform of a steady voltage applied to a lightning arrester unit arranged in each valve unit in the thyristor valve of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thyristor valve 1a, 1b ... Valve unit 2 ... Insulating pillar 3 ... Thyristor element 4 ... Valve arm 10 ... Laminated unit 11 ... Lightning arrester unit 12 ... Insulator tube 13 ... Characteristic element 14 ... Shield ring 20 ... Characteristic element pillar 40 ... Fiber reinforcement Plastic insulating cylinder 41 ... Heat shrink tube 42a, 42b ... Valve arm connection part

Claims (6)

[Claims] 1. A lightning arrester unit in which a characteristic element made of a non-linear resistor is housed in a porcelain insulator, and the lightning arrester unit is arranged between valve arms of a thyristor valve housing a plurality of thyristor elements. A lightning arrester characterized in that a laminated unit formed by vertically stacking a plurality of the lightning arrester units is arranged between two valve arms adjacent to each other among the arms. 2. A lightning arrester unit in which a characteristic element made of a non-linear resistor is housed in a porcelain insulator, and the lightning arrester unit is provided between valve arms of a thyristor valve housing a plurality of thyristor elements. Shield rings of the same diameter are respectively provided at both upper and lower ends of the plurality of valve arms, and between the two valve arms adjacent to each other among the plurality of valve arms, the plurality of arrester units are parallel to the plurality of thyristor elements. A lightning arrester characterized by being placed in parallel with each other. 3. A lightning arrester in which a lightning arrester unit in which a characteristic element made of a non-linear resistor is housed in a porcelain insulator is arranged between valve arms of a thyristor valve housing a plurality of thyristor elements. A plurality of laminated units formed by vertically stacking a plurality of lightning arrester units are arranged between two valve arms adjacent to each other among the arms, and a plurality of shields having the same diameter at the upper and lower ends of each lightning arrester unit. A lightning arrester, characterized in that each is provided with a ring, and the plurality of laminated units are arranged in parallel so as to be parallel to the plurality of thyristor elements. 4. The shield ring provided at the upper end of each lightning arrester unit is arranged at a position lower than the upper end surface of the characteristic element of each lightning arrester unit, and provided at the lower end of each lightning arrester unit. The shield ring is arranged at substantially the same height as the lower end surface of the characteristic element of each lightning arrester unit.
Lightning arrester described in any one of. 5. The characteristic element has a columnar structure formed by laminating a plurality of non-linear resistors, and the characteristic element having the columnar structure is parallel to the thyristor element in the insulator tube. The lightning arrester according to any one of claims 1 to 4, wherein a plurality of the lightning arresters are stored side by side. 6. The porcelain bushing is constructed by providing a heat-shrinkable tubular covering member around an insulating member made of fiber reinforced plastic, and the upper and lower end surfaces of the laminated unit or the arrester unit are both upper and lower sides thereof. The lightning arrester according to any one of claims 1 to 5, wherein the lightning arrester is fixed to each of the valve arms located at.