JPS6373879A - Water-cooled thyristor converter - Google Patents

Abstract

PURPOSE:To improve reliability, by providing the tie-ins of cooling water for a thyristor converter each at upper and lower sections of this converter, and by making it a tie-in of feedwater and a tie-in for drain respectively. CONSTITUTION:The cooling water discharged from a pump 16 is distributed to each module 8 from the floor of a valve hall 20, passing through an inlet distributing water pipe 12A, a main allocation pipe 10A and a distributing water pipe 11A for each thyristor module. The cooling water which cooled each module 8 is collected from a distribututing water pipe 11B for thyristor module to a main distributing water pipe 10B and led to a storage tank 13 provided on the roof of a control room 21 through an outlet distributing water pipe 12B to the ceiling of the valve hall 20. The cooling water is then discharged to a thyristor converter through a heat exchanger 14, an ion exchanger 15 and a pump 16. In this way, the quantity of flow of the cooling water communicating each module 8 is equally distributed, so that the increase of capacity of the pump, etc. can be dispensed with.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a thyristor conversion device for AC/DC conversion in DC power transmission or different frequency science systems, etc., and particularly relates to a water-cooled thyristor that cools by circulating a liquid. This invention relates to a conversion device.

(Prior Art) Semiconductor devices have made remarkable progress in recent years, and highly reliable high-voltage, large-current thyristor elements have been developed, and thyristor conversion devices using these thyristor elements are increasing in capacity year by year. Therefore, especially as the current increases, how to efficiently cool the components of the device has become a problem. 1' Insulating oil, air, etc. have conventionally been used as the cooling medium for the risk conversion device. However, the cold 7
There is a limit to the cooling performance of medium B. Therefore, many water-cooled thyristor conversion devices have been developed that are air-insulated and have a high cooling effect and are easy to maintain and inspect.

Generally, a thyristor conversion device constitutes a three-phase bridge circuit as shown in FIG. 7J' or 1U, 1v, 1
W, 2U, 2V, 2W1. AC system 1 is connected to AC terminals U, V, and W of the t-sai'J star valve, and 2.3 is a DC terminal. Furthermore, with the recent trend toward higher voltages and smaller valve holes, a three-phase bridge circuit consisting of valves 3U, 3V, 3W, 4U, 4V, and 4W is cascaded to the circuit in Figure 5, as shown in Figure 6. connected to.

A conventional water-cooled thyristor conversion device in which a thyristor conversion device connected as shown in FIG. 6 is cooled with water will be described with reference to FIGS. 7 to 9.

Fig. 8 shows a four-tiered thyristor conversion device and its cooling system, which is constructed by stacking 2U on top of 1U of thyristor valves, 3U on top of that, and then 4U on top of the thyristor valve 1U in the circuit of Fig. 6, and its cooling system. . Each = Iristor valve (1U will be explained here) consists of several thyristor elements 4 (6 in series in the figure) as shown in FIG. , a thyristor module 8 containing a capacitor 7 and the like is stacked in multiple stages using insulators.

Among the parts constituting the thyristor module 8, those that require cooling with water are the thyristor element 4, the anode reactor 5, and the voltage dividing resistor 6, which have large power losses.

When such a thyristor valve is cooled with water, main water pipes 10A and 10B made of insulators are connected to both ends of the thyristor module 8 by water pipes 11A and 11B for the thyristor module, respectively, as shown in FIG. There is. Further, at the ground level, an insulating inlet water pipe 12A and an outlet water pipe 12B are connected to the main water pipes 10A and 10B, and a storage tank 13, a heat exchanger 14, an ion exchanger 15, and a pump 16 are connected to each of them. ing.

Cooling water passes through the inlet water pipe 12△ by the pump 16,
The water is sent to the main water pipe 10△ and distributed to each thyristor module 8 by the water pipe 11A as shown by the arrow 17, and the above-mentioned parts are cooled by IJ'l. 10B, the water passes through the outlet water pipe 12B and is stored in the storage tank 13 at atmospheric pressure level. S1~
A cooling system is employed in which the water is cooled again from the rage tank 13 by a heat exchanger 14, purified by removing ions and impurities by an ion exchanger 15, and sent again to the thyristor conversion device by a pump 16.

Therefore, if the cooling system shown in FIG. 8 is plotted, it will become a cooling system diagram as shown in FIG. 9.

In addition, 18 in Fig. 8 is the frame of the thyristor valve, 1
Reference numeral 9 denotes an insulator that insulates and supports the entire four-stage thyristor valve. Further, 20 is a building called a valve hall where a thyristor valve is installed, and 21 is a building called a control room where a switchboard and monitoring equipment are installed. Normally, the voltage of one stage of such a thyristor valve is 125
In the kV class, the height is about 3'fTL, and as shown in FIG. 8, the height is about 12TrL as a four-stage thyristor conversion device. Furthermore, if the single hole is 25OkV class, the height will be nearly 20m when stacked in four tiers.

(Problems to be Solved by the Invention) Therefore, it becomes a problem to distribute the cooling water to the parts that require it at an even flow rate. FIG. 10 is a cooling system circuit diagram modeling the cooling system of the four-stage thyristor conversion device explained in FIG. That is, in FIG. 10, 22 is a fluid loss in the thyristor module 8, and 23 is a fluid loss in the water-cooled main tube 10. When distributing cooling water to each thyristor module 8 in such a cooling system, the flow rate of each thyristor module 8 decreases as it goes to the upper module as shown by the dotted line in FIG. This is determined by the ratio between the fluid loss 22 in each thyristor module 8 and the fluid loss 23 in the water-cooled main tube 10, and the larger the ratio, the smaller the slope of the graph in FIG. 3. Therefore, it would be better to reduce the fluid loss 23 of the water-cooled main pipe 10, but this is determined by the shape and thickness of the water-cooled main pipe 10, so it is hardly expected to reduce it, and conversely, the fluid loss of the thyristor module If 22 is increased, the capacity of the pump 16 must be increased,
The water pressure in the cooling system also increases, leading to problems with the reliability of the water pressure resistance of each component, water leakage, and increased costs.

Also, raise the cold water to a height of 1070 or higher to cool it down! In the case of such a tower-configured thyristor conversion device, if the pump 16 is stopped due to maintenance or inspection or for some other reason, the water in the piping in the thyristor module 8, etc. located 10 meters or more above will drop to atmospheric pressure. Depending on the relationship, for example, in the case of 1 atm, the distance may drop to 10 m. Naturally, the inside of the pipe where the water has descended becomes a vacuum.

Therefore, most of the piping used in thyristor converters requires insulation, so insulated piping is used, and as mentioned above, insulated piping can collapse and break when it becomes vacuum, and further vacuum can cause discharge. This tends to cause problems such as dielectric breakdown and reduced reliability of the thyristor conversion device.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a highly reliable water-cooled thyristor converter without any adverse effects on the thyristor converter.

[Structure of the Invention] (Means for Solving the Problems) The present invention will be described below with reference to FIGS. 1 to 4. still,
Identical parts in FIGS. 5 to 10 are given the same symbols.

In order to achieve the above object, the present invention has the following features as shown in FIG.
A cold W water connection of the thyristor conversion device is provided at each of the upper and lower portions of the conversion device, and each serves as a water supply connection and a drainage connection. Furthermore, the storage tank 13 is installed on the roof of a building such as the control room 21, and the head difference between the water level in the storage tank 13 and the top of the closed circulation cooling water pipe 12 is less than 10 m, that is, 1 atmosphere or less with pressure exchange. The storage tank 13 is arranged as shown in FIG.

(Function) FIG. 2 is a circuit diagram of the cooling system shown in FIG. 1, showing the present invention. Since the pressure loss in each flow path from the water supply connection to the drain port is equal, and the flow rate is balanced, the flow rate through each module is equal, as shown by the solid line in FIG. 3. Also, if the storage tank is arranged as shown in Figure 1 and the head difference between it and the closed circulation cooling water piping 12 is within 10 m, the water in the cooling piping will not fall due to atmospheric pressure even if the circulation pump 16 stops. Therefore, there is no vacuum inside the piping.

<Example) Embodiments of the present invention will be described below with reference to FIG.

The cooling water discharged from the pump 16 passes from the floor of the valve hole 20 through the inlet water pipe 12A, and from the water supply fitting provided at the bottom of the thyristor conversion device, passes through the main water pipe 10A and the water pipe 11A for each thyristor module. Water is distributed to module 8.

The cooling water that has cooled each module 8 passes through the thyristor module water pipe 11B and is collected in the main water pipe 10B, exits from the water distribution joint on the top of the η iristor converter, and flows to the ceiling of the valve hole 20 through the insulator outlet water pipe 12B. Handling is restricted i2
Enter the storage tank 13 installed in the rice field in the 0 block 21. The cooling water further passes through a heat exchanger 14 to lower its temperature, passes through an ion exchanger 15, increases the purity of the cooling water, and is again discharged to the thyristor conversion device by a pump 16. The cooling system has a closed circulation system and is installed on the roof of the control room 21 so that the drop between the top of the piping system and the water level of the storage tank 13 is at least 10 m or less.

With this configuration, the flow rate of cooling water passing through each module 8 is evenly distributed as shown by the solid line in FIG. There is no need to increase the capacity of
Water pressure can be low, and there are no problems with water leakage or water pressure resistance of parts.

Furthermore, even if the pump 16 were to be stopped, the water in the pipes would not fall due to the atmospheric pressure, so a vacuum would not be created in the pipes, which would cause damage to the pipes due to the insulating material and insulation breakdown due to rll electricity. We are able to provide a highly reliable water-cooled Guirista neck mount without any problems.

In Fig. 1, a floor-mounted thyristor converter was explained, but a suspended type thyristor converter 1' suspended from the ceiling
It goes without saying that it can be applied to devices such as Lister Variation]*. or,
Although the cooling water is circulated in the lower part of the thyristor converter, the same effect can be obtained even if the circulation system is in the opposite direction.

FIG. 4 shows a further embodiment of the present invention.

A pipe 24Δ that also serves as water storage is installed on the ceiling of the valve hole 20, and a pipe 24 that also serves as water storage is provided at the bottom of the thyristor conversion device.
B is configured such that one or more insulating vibrators 25 are connected between the pipes 24A and 248, and the other pipes are connected to the first pipe.
Same as the figure.

Normally, the top of the thyristor conversion system device is at a high voltage level, and the ceiling piping of the valve hole 20 is at the ground voltage level, so insulation is required during this time. In this case, if the diameter of the insulating vibrator is large, leakage current will increase, causing problems such as electrolytic corrosion. Moreover, if the diameter is small, the flow velocity increases, which increases pressure loss. Therefore, these problems can be avoided by adopting a configuration as shown in FIG. Also, the difference between the water surface of the storage tank 13 and the top of the cooling arrangement is 1
0m or more, even if the pump 16 stops and the water in the thyristor converter piping drops, the piping 24, which also serves as water storage, is replenished with cooling water, and at least the piping section made of insulators is kept in a vacuum state. It is designed not to form. Thereby, the same effect as the thyristor conversion device shown in FIG. 1 can be obtained. In FIG. 4, the thyristor conversion device of the floor-mounted type was explained, but it goes without saying that the present invention can also be applied to a hanging-type thyristor conversion S device suspended from the ceiling. Also, the same effect can be obtained even if the direction of circulation of the cooling water is reversed.

[Effects of the Invention] As explained above, according to the present invention, the flow rate of each thyristor module in a water-cooled thyristor conversion device is evenly distributed without increasing the pump capacity or upper limit of water pressure. ) and the water pressure resistance of each part are eliminated, and even if the pump stops or malfunctions, it can be converted to a thyristor)! To provide a highly reliable water-cooled thyristor conversion device that prevents the cooling water on the i-equipment side from dropping, thereby preventing the inside of the piping from becoming a vacuum and causing no damage to the piping or dielectric breakdown due to discharge. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a cooling system of a thyristor conversion device showing an embodiment of the present invention, and Fig. 2 is a diagram modeling the cooling system of the thyristor conversion device of Fig. 1 without showing an embodiment of the present invention. ,
FIG. 3 is a diagram showing the flow rate in each stage module of the conventional thyristor conversion device and the present invention, FIG. 4 is a block diagram of the cooling system of the thyristor conversion device showing another embodiment of the present invention, and FIG. Figure 6 is a thyristor valve connection diagram, Figure 7 is a circuit diagram inside the thyristor module that constitutes the thyristor valve, Figure 8 is a configuration diagram of a cooling system of a conventional thyristor conversion device, and Figure 9 is a diagram of the cooling system of a conventional thyristor conversion device. FIG. 10 is a diagram modeling the cooling system of the thyristor converter shown in FIG. 8, which shows a conventional example. 1... AC system, 1U~4W... Thyristor valve, 2.3... DC terminal, U, V, ~ ■... AC terminal, 4... Thyristor element, 5... Anode reactor , 6... Voltage dividing resistor, 7... Capacitor, 8...
Thyristor module, 9...Insulator, 10A, 10B
...Main water pipe, 11A, 11B...Water pipe, 12A
...Inlet water pipe, 12B...Outlet water pipe, 13...
・Storage tank, 14... Heat exchanger, 15...
Ion exchanger, 16...pump, 17...arrow, 1
8...Frame, 1...Insulator, 20...Valve hole, 21...Control room, 22...Thyristor module fluid loss, 23...Water-cooled main tube fluid loss, 24A
, 24B... Water storage piping, 25... Insulated vibrator. Applicant's Representative Patent Attorney Takehiko Suzue No. 121 Figures 2-1, 1-3, Figure 4, Figure 5, Figure 7, Figure 2, Figure 8, Figure 9

Claims (1)

[Claims] Modules containing multiple thyristor elements and their associated circuits are stacked in several stages using insulating supports to generate a specified voltage.
A multi-tiered water-cooled thyristor conversion device in which one unit is a thyristor valve which is connected so as to conduct current and water-cools a heating element such as a thyristor element, resistor, or reactor in the module, and the units are stacked in several stages. The water supply connection and the drainage connection of the cooling water main pipe are provided at the bottom and top of the thyristor converter, respectively, and the circulation cooling water system is provided with a circulation water pump, an ion exchanger, a heat exchanger, a storage tank, and a circulation cooling water system. 1. A water-cooled thyristor conversion device comprising cooling water circulation piping, wherein the head difference between the top of the cooling water circulation system and the water surface of the storage tank is about 10 m or less.