JPS6149908B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thyristor valve that is most suitable for application to AC/DC conversion in DC power transmission or interconnection between different frequency power systems.

Most of the thyristor valves used for DC power transmission or interconnection between systems of different frequencies are air-cooled thyristor valves due to the recent trend towards higher voltages and ease of maintenance and inspection. A conventional air-cooled thyristor valve will be explained below with reference to FIGS. 1 to 8.

Figure 1 is an internal circuit diagram of the module, Figure 2 is a cross-sectional plan view of a conventional thyristor valve, Figure 3 is a front view, Figures 4 and 5 are layout diagrams of the thyristor valve, and Figure 6 is the number of modules. FIG. 7 is a diagram showing the relationship between the surge voltage and the overvoltage.

As shown in Fig. 1, the air-cooled thyristor valve includes a thyristor stack 2 in which a plurality of thyristor elements 1 are connected in series and parallel, an anode reactor 3 connected in series with the thyristor stack 2, and an anode reactor 3 connected in series with the thyristor stack 2. A plurality of modules 7 housing a voltage dividing circuit 4 and a damping circuit 5 connected in parallel, each thyristor element 1, and an ignition circuit 6 for ignition are arranged on both sides of the wind tunnel 8 as shown in FIGS. 2 and 3. These are one stage 9 ₁ , two stages 9 ₂ , . . . n stages 9 _o , and each stage is stacked and connected in several stages by insulating supports 10. Note that 11 is an insulator that insulates and supports the bulb from the ground.

When a steep surge is applied between the anode and cathode of a thyristor valve with such a configuration, if a plurality of modules 7 are used as one stage as shown in Fig. 6, an equal pull is applied between each stage. No applied voltage is applied, but due to the presence of stray capacitances C1, C2, Cn-1, and Cn, the stage on the surge application side shares a larger voltage than the stage on the grounded side.

That is, in FIG. 6, if we assume that the anode end A is the surge application end, the cathode end K is the ground end, and that there are no stray capacitances C1, C2, Cn-1, and Cn, then the surge current is flows from the anode end A to the cathode end K without being divided elsewhere. Also, if the number of modules in each stage is the same, the impedance of each stage will also be almost the same, and if that value is Z, the voltage sharing of each stage will be the product of the impedance Z and the current is, which will equalize the surge voltage. It will be shared.

However, in reality, there are stray capacitances C1, C2, Cn-1, and Cn between the stage and the ground, so in Fig. 6, the anode end A is the surge voltage application end, and the cathode end K is the ground end. In this case, when a surge voltage with a rise time of about 1 μs is applied as shown in Figure 7 Es, the stray capacitance acts and a part of the surge current flows through each stray capacitance C1, C.
Divides into 2... Therefore, the stage 9 ₁ at the application end
Even if a surge current is flowing through the capacitor C1, a part of the surge current is flowing to the next stage ₉₂ .
Therefore, if this shunted current is i1, a current of is-i1, which is smaller than is, flows. In this way, the surge current flowing in stages closer to the surge voltage application end, that is, the non-grounded end, is smaller as the stage is closer to the grounded end.
The stage on the non-grounded end side will share the maximum amount of the surge voltage.

Further, in FIG. 6, if the anode end A is set as the ground end, the surge voltage will enter from the cathode end K, so that the stage on the cathode end K side will share the maximum amount of the surge voltage.

If a surge is applied to the valve as described above,
The maximum overvoltage is applied to the stages near the anode and cathode ends of the bulb, so this must be taken into account when determining the insulation of the bulb, that is, the insulation distance between each stage. In other words, from Figures 3 and 6, 9 ₁
Stage and 9 Stage ₂ and 9 _o Stage and 9 _o-1
The insulation distance between stages must be maximized, and due to the valve configuration, the distance between each stage is not constant, causing problems in work, assembly, or maintenance inspection. Distance has to be considered, and the disadvantage is that the height of the valve becomes large.

Also, as a way to find out the number of destroyed thyristor elements during periodic inspections, etc., separate the valve's anode and cathode from other circuits, and apply a specified DC voltage between the valve's anode and cathode.
By measuring the DC impedance at that time, the number of thyristor elements must be determined by destroying them. Therefore, this work must be done efficiently, quickly, and safely since it is located at a high location.The positions of the anode and cathode terminals of the valve are as shown in Figures 4 and 5.
If the main circuit is attached to a surface other than the inspection surface, a work stand must be assembled to disconnect the main circuit, which not only requires a lot of time but also reduces economic efficiency. Additionally, safety problems arise, and the operating efficiency of the valve is reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and provide a highly reliable thyristor valve that is compact, easy to maintain and inspect.

The present invention will be explained below with reference to FIGS. 8 to 10.

The number of thyristor elements 1 and the configuration of the stack 2 are taken into consideration so that the number of stages near the anode and cathode poles of the valve, the _91st stage and the _9o stage are smaller than the other stages, as shown in FIG. As shown in FIG. 9, the valve is constructed so that the empty module 12 is disposed at the position closest to the anode and cathode of the valve in the ₉₁ and _9o stages. In addition, a connection part 13 is made in the air module 12 to connect the main circuit parts of the anode and cathode of the valve, and by removing the connection conductor 14 at the connection part 13, the valve can be disconnected from other circuits. It becomes the composition.

As described above, by making the number of modules in the stage closer to both the anode and cathode electrodes of the valve smaller than the number of modules in the other stages, the seventh
As shown by the broken line in the figure, the overvoltage applied to the stage near the application end is at approximately the same level as the voltage applied to the other stages.

Therefore, when considering insulation between each stage, the applied overvoltage is approximately the same, so it is sufficient to maintain the same insulation distance between all stages, and the applied overvoltage is also lower than in the case of the conventional valve configuration, so The insulation distance may be small. Furthermore, the first
A lifter for inspecting the module can be used because there is a connection part on the surface where the module housing the circuit shown in the figure is attached that can be disconnected from other circuits. Therefore, the DC impedance measurement during valve inspection as described above can be carried out safely and smoothly, and the time required to restart the valve can be greatly shortened.

As described above, according to the present invention, the insulation distance between each stage is required to be small, making the entire valve compact, and inspection work can be done in a short time and safely, improving the reliability of the valve as a whole system. .

[Brief explanation of the drawing]

Figure 1 is the module internal circuit diagram, Figure 2 is the 3rd diagram.
XX sectional view in the figure, Figure 3 is a front view of a conventional valve, Figures 4 and 5 are valve layout diagrams, Figure 6 is a diagram of the relationship between the module and stage, and Figure 7 is the applied voltage. and overvoltage waveform diagram acting on each stage, 8th
The figure is a relationship diagram between a module and a stage showing an embodiment of the present invention, Fig. 9 is a Y-Y sectional view of Fig. 10, and Fig. 10 is a front view of a valve showing an embodiment of the present invention. . 1... Thyristor element, 2... Stack, 3...
...Anode reactor, 4...Voltage divider circuit, 5...
Damping circuit, 6... Element ignition circuit, 7... Module, 8... Wind tunnel, 9... Stage, 10...
...Insulating support, 11...Insulator, 12...Empty module, 13...Main circuit connection part, 14...Connection conductor.

Claims (1)

[Scope of Claims] 1 A plurality of modules containing a plurality of thyristor elements and their associated circuits are arranged to form one stage, and the stages are stacked in multiple stages using insulating supports to obtain a specified voltage and current. A thyristor valve connected to the thyristor valve in which either the anode end or the cathode end is grounded, characterized in that the number of modules in the stage closest to the ungrounded end of the thyristor valve is smaller than the number of modules in the other stages. thyristor valve. 2 A plurality of modules housing a plurality of thyristor elements and their attached circuits are arranged to form one stage, and the stages are stacked in multiple stages with insulating supports, connected to provide specified voltage and current, and connected to the anode end or In a thyristor valve in which one of the cathode ends is grounded, the number of modules in the stage closest to the non-grounded end of the thyristor valve is reduced compared to the number of modules in the other stages, so that the number of modules in the stage closest to the non-grounded end of the thyristor valve is reduced to A thyristor valve characterized in that a pneumatic module is provided in a close position, and a disconnectable connection body is provided within the pneumatic module.