JPH0787742A - Water-cooled thyristor valve and manifold - Google Patents

Abstract

PURPOSE:To provide a solid cooling-water pipe which can cool a thyristor module uniformly and whose installation area is minimum. CONSTITUTION:Electrically insulated pipes 10 which supply pure water used to cool thyristor modules 1 are arranged in regions excluding a space which is constituted of a first-stage frame 3 and of a floor face 50 and excluding a space which is surrounded by lengths of + or -10% of a frame width in the horizontal direction from end parts of frames in individual stages and of + or -10% of a frame interstage distance. In addition, the electrically insulated pipes 10 are bent to be crank-shaped in a plurality of parts, and they are connected to manifolds 9 in the individual stages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-cooled thyristor converter for AC / DC conversion between DC power transmission or different frequency power systems, and more particularly to a thyristor valve cooled with pure water.

[0002]

2. Description of the Related Art Due to the recent energy situation in Japan, there is an increasing demand for high-efficiency transmission of large electric power over a long distance. On the other hand, large-capacity power thyristors have been put into practical use, have become easily available, and have been applied to frequency conversion, DC power transmission, etc. in response to the power situation. In this thyristor valve, a large amount of heat is generated from the constituent parts of the thyristor valve, in particular, the thyristor in order to process a large current, and recently, in order to efficiently cool this, the mainstream is to circulate pure water for cooling. In addition, higher voltage is required to transmit large power with high efficiency over a long distance, and accordingly, the thyristor valve is made high-layer, and when transmitting at 1000 KV, the valve height reaches 10 m or more. When the thyristor valve is increased in number of layers, a means to evenly and efficiently cool it, a robust and highly safe piping structure, a means to reduce leakage current and suppress electrolytic corrosion, and a compact installation to reduce the cost of constructing valve holes The structure that can be created is a technical issue.

As shown in FIG. 1, a thyristor valve is constructed by mounting a thyristor module 1 on an insulating column 2 together with a frame 3 in a layered manner. As shown in FIG. 2, the thyristor module 1 is composed of a plurality of thyristor elements 4 and its associated circuit, an anode reactor 5, a resistor 6, a capacitor 7 and the like. Of these, those that require cooling are the thyristor element 4 , The anode reactor 5, the resistor 6, etc., and the cooling water is supplied through the cooling pipe 8.

FIG. 9 shows the structure of a cooling system for a conventional thyristor valve, and a manifold 9 is provided at each stage of the thyristor valve so as to correspond to the thyristor module. The manifold 9 is connected by a plurality of electric insulation pipes 10, a cooling water mother pipe 11, a circulation pump 12, a heat exchanger (cooler) 13, an ion exchanger 14,
A cooling water circulation system is configured with the cooling tower 15. The thyristor module 1 is connected to the manifold 9 by a branch pipe 16 and receives distribution of cooling water. The heat exchanger (cooler) 13 transfers the amount of heat generated from the components forming the thyristor module 1 to the cooling tower 15 to dissipate the heat to the outside of the system. The ion exchanger 14 removes the ions eluted from the circulation system to increase the specific resistance of the circulating water and reduce the leakage current amount.

[0005]

In order to reduce the leakage current due to the cooling water in the above thyristor valve, it is necessary to reduce the cross section of the pipe passage of the cooling water pipe, but this becomes a factor to increase the pressure loss. Furthermore, it is necessary to pump water to a height of 10 m or more at the top of the thyristor valve, but this also increases the pipe internal pressure, and it is necessary to have a strength that can withstand this, and when the circulating water circulation stops Although it will fall down and the inside of the pipe will be in a vacuum state, a robust and highly safe pipe structure is required so that the pipe will not be damaged by this.

Further, when a plurality of thyristor modules 1 are arranged, it is necessary to improve the arrangement and piping of the thyristor modules that minimize the installation area in order to reduce the construction cost.

Further, as described above, when the thyristor valve is required to have a high voltage and a large current, the number of thyristor modules increases and the height of the thyristor valve reaches 10 m or more. Means for uniform water supply will be an important technical issue.

Further, there has been required a means for reducing the flow path loss at each stage in order to reduce the stress acting on the cooling water piping by lowering the operating pressure of the cooling water circulation system.

The present invention has been made in accordance with the above need, and by providing a means for uniform cooling, a compact and robust pipe means, the economical efficiency of the thyristor valve and the cooling system. It seeks to improve the reliability and safety of.

[0010]

A water-cooled thyristor valve according to the present invention supports a predetermined number of thyristor modules, each containing a thyristor element and its associated circuit, by insulating columns, and the thyristor module group is mounted between a plurality of frames. In addition to stacking in multiple stages and cooling water piping for cooling the heat generated inside the thyristor module, the space formed by the first stage frame from the floor and the floor, and the end of each stage frame The cooling water pipe is arranged in a region excluding a space within a distance of ± 10% of the frame width in the horizontal direction from the above portion and a distance of ± 10% of the frame step distance in the vertical direction.

Further, the cooling water manifolds of the respective stages are connected by electric insulation pipes which are bent in a crank shape at a plurality of places, and the surface formed by the bent electric insulation pipes is perpendicular to the side surface of the thyristor module. It is configured to incline.

Further, water is supplied independently from the bottom or top of the thyristor valve mount to each thyristor module by a plurality of cooling water supply pipes.
The cooling water return path is configured so as to be independently taken out from the thyristor module of each stage toward the top or bottom of the thyristor valve mount opposite to the above water supply path to return water.

Further, in the manifold connecting the branch pipe for distributing the cooling water to the thyristor module, the manifold main body is constituted by a plurality of branch pipes penetrating in a direction perpendicular to the axis of the manifold main pipe and the manifold main pipe. One or more pressure equalizing holes are provided in a part of the branch pipe located inside the pipe.

[0014]

In the water-cooled thyristor valve of the present invention, since the cooling water pipe is arranged by selecting the region having a small electric gradient, the insulating pipe having a relatively low corona characteristic and the electrically insulating pipe having the multilayer structure can be used. As a result, a robust and safe cooling water pipe can be realized. In addition, it is possible to improve the routing of the cooling water pipe and minimize the installation area of the thyristor valve. Furthermore, the cooling operation pressure can be reduced, the stress acting on the cooling water pipe can be reduced, and the flow path loss can be minimized. Further, reliability for cooling is improved by providing a means for supplying cooling water evenly to the thyristor module.

[0015]

EXAMPLES Example 1. The cooling water pipe of the water-cooled thyristor valve is required to have good electrical insulation properties and one without elution of ionic impurities. Moreover, since the thyristor valve is operated under high pressure, a tetrafluoroethylene tube is generally used because it does not cause corona in the minute gaps and voids in the material to cause insulation deterioration. .. However, this is a relatively soft material, and its strength decreases at high temperatures, and at 60 ° C, it is
It decreases to 0% and 60% at 80 ° C. In the ultrapure water system, organic microorganisms grow over time, so 80
The inside of the system may be sterilized by circulating hot water of ℃ or higher.
For the cooling pipe of the thyristor valve, it is necessary to use a thick pipe that can withstand the circulating operating pressure even in this temperature range.

However, since the tetrafluoroethylene tube is expensive and used only for special purposes, availability of thick pipes is limited. Therefore, as shown in FIG. 10, a multi-layered pipe structure in which the outside of the tetrafluoroethylene pipe 10a is reinforced with a strong pipe 10b is conceivable. On the other hand, in the case of a multi-layer structure pipe, if there is a gap between layers, the corona resistance is deteriorated, so it is necessary to select an environment in which the pipe is installed so that corona does not occur in the pipe.

FIG. 3 shows 250 at the bottom of the thyristor valve.
9 shows an example of equipotential distribution when a voltage of KV and a voltage of 500 KV is applied to the uppermost stage. The electric field is concentrated near the end of the frame 3 that partitions the plurality of thyristor modules and between the floor surface 50 and the first-stage frame and the floor surface 50, and the potential gradient becomes large, but it deviates from that region. And the potential gradient becomes low. In this embodiment, the first thyristor valve is constructed from the area where the potential gradient is small, that is, the floor surface 50.
Space (A area) formed by the frame 3 and the floor surface 50 of the tier, and ± 10% of the frame width in the horizontal direction from the end of the frame 3 of each tier, and ± 10% of the distance between the frame tiers in the vertical direction. Since the potential gradient of the space (C region) excluding the region (B region) surrounded by the length is 0.1 KV / MM or less, by arranging the cooling water pipe in this region (C region),
It is possible to use a pipe having a multi-layered structure of a material having low corona resistance or a pipe structure thereof, and to provide a cooling water pipe having sufficiently high strength and high safety. For example, the cooling water pipe is reinforced with the same material as that of the insulating column 2 to which the thyristor module 1 is attached, or a resin (Teflon resin, tetrafluoroethylene) having an electric insulation property higher than that, or an insulating fiber such as glass fiber. A multi-layered tube or the like coated with the above resin may be used.

Example 2. An example of the arrangement of the cooling water pipes according to the present invention is shown in FIGS. In FIG. 4, the electrical insulation pipe 10 is bent into a crankshaft shape a plurality of times to connect between the manifolds 9 of each stage, and each manifold 9 is connected to a branch pipe 16
The cooling water is sent to and received from each thyristor module 1 through. As described above, by bending the electric insulating pipe 10 a plurality of times, the pipe length of the cooling pipe is lengthened so that the amount of leakage current is less than the specified value and the creepage distance is lengthened. A plurality of thyristor modules 1 are arranged in each stage of the thyristor valve mount, and the surface of the electrically insulated pipe 10 bent in a crank shape as shown in FIG. The installation area of the thyristor mount is reduced by arranging the thyristor modules at an angle θ and arranging the thyristor modules at high density by packing them.

Example 3. The thyristor valve has a structure in which a plurality of thyristor modules 1 are vertically arranged and a plurality of thyristor modules 1 are arranged in each stage. The number of thyristor modules and the number of stages increase as the processing power becomes a high voltage and a large current, and a means for evenly distributing the cooling water to each module is required. FIG. 9 shows an example of conventional piping. A manifold 9 is provided in each stage, and the thyristor module 1 arranged in the same stage is connected to the manifold 9 by a branch pipe 16 to receive water supply. The manifolds 9 in each stage are connected by a plurality of electric insulation pipes 10 and the number of the manifolds 9 is reduced every time water is supplied and received in each stage. The primary side (water supply side) has a plurality of electrical insulation tubes 10 from the bottom of the thyristor valve mount.
Water is supplied through the pipes, and the number of the insulating tubes 10 is reduced each time each step goes up. On the other hand, on the secondary side (return side), the number of insulating tubes 10 is increased from the upper stage to the lower stage, and water is returned to the circulation system from the lowest stage. In this method, since the pipe resistance is different for each stage, it is necessary to adjust the water amount by using some kind of adjusting means in order to supply water evenly to each stage. FIG. 6 shows a piping configuration example of the cooling water piping according to the present invention. While supplying water to a plurality of electric insulating pipes 10 from the lowermost stage of the thyristor valve pedestal through a cooling water mother pipe 11a for supplying water, the number of the insulating pipes 10 is sequentially reduced toward each upper stage. On the secondary side (return side), the number of the insulating tubes 10 is sequentially increased toward the upper stage, and after collecting water at the uppermost stage, a region having a small potential gradient except for the regions A and B shown in Example 1. Water is returned to the cooling water mother pipe 11b for water return arranged in (C region). With this configuration, all flow path resistances to the thyristor module 1 have the same value, and the flowing water amount can be equalized without the water amount adjusting means. Further, if the cooling water mother pipe 11b for returning water is electrically insulated from the thyristor valve body by an electrically insulating pipe and is arranged in a region having a small potential gradient, for example, a large-diameter and robust pipe can be used even if the insulating property is low, An inexpensive and highly safe cooling water pipe can be realized. In the above description, the cooling mother pipe 11a sequentially supplies water from the lowermost stage, collects water at the uppermost stage, and returns the water to the cooling water mother pipe 11b for returning water.
The flow of cooling water may be reversed and pumped up to the uppermost stage by the cooling water mother pipe 11b, supplied from the uppermost stage, and returned to the cooling water circulation system from the lowermost stage.

Example 4. A manifold for cooling water is provided at each stage of the thyristor valve, and reducing this fluid loss is important for lowering the operating pressure of the cooling water circulation system and reducing the stress generated in the cooling pipe. FIG. 7 shows a configuration example of a conventionally used manifold, in which a plurality of branch pipes 18 are attached to a manifold mother pipe 17.
The branch pipe 18 is configured to connect the electrical insulating pipe 10. Then, in order to equalize the amount of water flowing through the plurality of electrical insulating pipes 10, the flow is merged and split in each manifold of each stage, but in this method, the fluid in the manifold is disturbed. However, there is a drawback that the pressure loss increases. FIG. 8 shows a configuration example of a manifold that solves this drawback. In this example, a plurality of branch pipes 18 having the same diameter as the electrical insulating pipe 10 are passed through in a direction substantially perpendicular to the axial direction of the manifold main pipe 17 forming the manifold, and a part of the branch pipe 18 located inside the manifold is penetrated. One or a plurality of pressure equalizing holes 19 are provided. The electrically insulating pipes 10 connecting the manifolds of the respective stages are connected to both ends of the branch pipe 18. According to this embodiment, the electrical insulation pipe 10 is pressure-equalized for each manifold in each stage of the thyristor valve, and the amount of flowing water is also equalized thereby. In addition, since the cross section of the flow path is continuous and uniform, there is no turbulence in the flow and there is an effect that the fluid loss can be reduced.

[0021]

As described above, according to the present invention, a robust and highly safe cooling water pipe can be realized by selecting a region having a small electric gradient and arranging an electrically insulating pipe having a multi-layer structure. The reliability of cooling is improved by providing a means for supplying the cooling water evenly. Further, the effect of the present invention is great such that the installation area of the thyristor valve and the cooling operation operating pressure can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of a thyristor valve.

FIG. 2 is a configuration diagram of a thyristor module that constitutes a thyristor valve.

FIG. 3 shows a potential distribution diagram of a thyristor valve.

FIG. 4 is a side view showing an embodiment of a thyristor valve cooling water pipe of the present invention.

FIG. 5 is a plan view of the cooling water pipe for the thyristor valve.

FIG. 6 shows a configuration example of a thyristor valve cooling water piping system of the present invention.

FIG. 7 is a cross-sectional view showing a conventional manifold.

FIG. 8 is a cross-sectional view showing a configuration example of the manifold according to the present invention.

FIG. 9 shows a configuration example of a conventional thyristor valve cooling system.

FIG. 10 shows a configuration example of a conventional multilayer piping structure.

[Explanation of symbols]

 1 Thyristor module 2 Insulation column 3 Frame 4 Thyristor element 5 Anode reactor 6 Resistance 7 Capacitor 8 Cooling pipe 9 Manifold 10 Electric insulating pipe 11a, b Cooling water mother pipe 12 Circulation pump 13 Heat exchanger 14 Ion exchanger 15 Cooling tower 16 Branch pipe 17 Manifold mother pipe 18 Branch pipe 19 Pressure equalizing hole

Claims (4)

[Claims] 1. A predetermined number of thyristor modules accommodating thyristor elements and their associated circuits are supported by insulating struts, the thyristor module group is stacked in multiple stages between a plurality of frames, and heat generated in the modules is cooled. In a water-cooled thyristor valve equipped with cooling water piping for the space, the space between the floor and the frame of the first stage and the floor, and the frame width ±
A water-cooled thyristor valve, wherein the cooling water pipe is arranged in a region excluding a space surrounded by 10% and a length of ± 10% of a frame step distance in the vertical direction. 2. A predetermined number of thyristor modules accommodating thyristor elements and their associated circuits are supported by insulating struts, the thyristor module group is stacked in multiple stages between a plurality of frames, and heat generated in the modules is cooled. In a water-cooled thyristor valve having a cooling water piping system for, the cooling water piping system is connected to the cooling water manifold of each stage through a plurality of electric insulating pipes bent at a plurality of points, and the bent electric insulating pipes are connected. A water-cooled thyristor valve characterized in that the surface formed by the parts is attached to be inclined with respect to the vertical surface of the side surface of the thyristor module. 3. A cooling water pipe for cooling a plurality of thyristor modules, in which a plurality of thyristor modules accommodating a thyristor element and its accessory circuits are supported by insulating columns, and the thyristor module group is stacked in a plurality of stages between a plurality of frames. In a water-cooled thyristor valve equipped with a water cooling system, a plurality of cooling water supply pipes are used to supply water independently from the bottom or top of the thyristor valve mount to each thyristor module, and the cooling water return path is the above-mentioned water supply path. Reversed from the thyristor valve, a water-cooled thyristor valve that is configured to take out and return water independently from each stage thyristor module toward the top or bottom. 4. A manifold for connecting a branch pipe for distributing cooling water to a plurality of thyristor modules arranged in a plurality of stages, in a manifold mother pipe and a plurality of branch pipes penetrating in a direction perpendicular to the axis of the manifold mother pipe. A manifold body comprising: a manifold main body; and one or more pressure equalizing holes provided in a part of the branch pipe located inside the manifold main pipe, and the branch pipe being connected to the branch pipe.