JP2971816B2 - Bypass switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bypass switch device, and more particularly, to a bypass switch device suitable for a gas-insulated conversion station for DC power transmission.

[0002]

2. Description of the Related Art As shown in FIG. 2, converters are provided at both ends of a DC transmission line L, one converter A is a forward converter, and the other converter B is a basic converter. Inverter. The converters A and B are respectively connected to AC systems LA and LB via converter transformers TA and TB.
Connected to

In order to increase the DC transmission voltage, each converter is configured by stacking thyristor valve stacks in multiple stages, for example, in two stages. When an accident occurs in any of the stack groups, or when the operation of some of the stack groups is stopped for maintenance and disconnection from the system, only the remaining stack groups are operated to reduce the transmission voltage However, it is considered to prevent the total power outage by continuing the power transmission.

[0004] Usually, when such a stack group is disconnected from the system, a bypass switch electrically connected to the stack group in parallel is used.

The functions required of this bypass switch include the following: in order to quickly short-circuit the stack group and to bypass the load power when the failure, inspection and load reduction of the stack group are performed, the separated stack group is used. After the restoration, the DC current may be cut off without giving an abnormal voltage to the thyristor valves in the stack group, and steady DC power transmission may be continued.

FIG. 3 shows an example of the structure of one positive pole of a forward converter provided with such a bypass switch. In this example, the stack groups ST and ST ′ having the same configuration are stacked in two stages.

[0007] The stack groups ST and ST 'constitute a three-phase full-wave rectifier circuit by connecting the thyristor valve stacks a to f and a' to f 'with gratings.
T 'is connected to the AC system, and the DC terminal is connected to the disconnector LS,
It is connected to DC transmission lines L and L 'via LS'.

R and R 'are thyristor protection reactors connected in series to the thyristor valve stacks a to f and a' to f '; SA and SA' are surge absorbers;
S and BS 'are bypass switches each provided with a cutoff unit composed of two cutoff unit units 1A and 1B; 2A and 2B electrically connected in series.

In the configuration of FIG. 3, for example, when the thyristor valve of one stack group ST breaks down or the load is reduced, the bypass switch BS is turned on to short-circuit both ends of the stack group ST, and the other stack group ST is short-circuited. The current on the ST 'side is instantaneously switched to the bypass switch BS side, and then the disconnector LS is opened, and the thyristor valve on one of the stack groups ST is inspected and restored.

After the recovery, the disconnector LS is turned on, and an opening command is given to the bypass switch BS to perform the opening operation.
At this time, since the firing pulse is supplied to the bypass pair valve stacks a and d, each of the cutoff unit 1A, 1
Arcs 3A and 3B are generated between the poles of B, and when the arc voltage reaches or exceeds the minimum ignition voltage of the bypass pair valve stacks a and d, the bypass pair valve stacks a and b conduct, and several amps of A current is bypassed to form a bypass circuit short-circuiting both ends of the bypass switch BS.
After the short-circuit bypass circuit is formed, the current is further limited by the arc voltage to generate a current zero point and extinguish the arc. Then, each thyristor valve stack a to f
By supplying a firing pulse to the stack group ST to perform a steady operation, the current from the other stack group ST 'is switched to the restored stack group ST, and the DC current of apparently several hundred to several thousand amperes Has been cut off.

By the way, as the above-mentioned bypass switch, an air circuit breaker for AC cutoff as shown in FIG. 8 has been conventionally applied as described in Japanese Patent Publication No. 54-12964. That is, the compressed air storage tank 4
A pair of air cut-off units 6A and 6B mounted thereon via insulators 5A and 5B, a rotary disconnection unit 8 having a blade 7 disposed between the air cut-off units 6A and 6B, A bypass switch including an air drive operation mechanism 9 is used. This is because the responsibility of the bypass switch is to generate a high arc voltage and maintain it for a predetermined time.However, the air circuit breaker has a large arc potential gradient and a high arc voltage can be easily obtained. It is because it is suitable for.

[0012]

In recent years, attempts have been made to develop a DC gas insulated converter. When a bypass switch is installed in a DC gas insulated converter, an air circuit breaker that is compressed air insulated and releases compressed air to the atmosphere during shutoff operation is applicable to SF ₆ gas insulated and hermetically sealed gas insulated converters. Is inappropriate to do. On the other hand, the arc voltage is low in a gas circuit breaker that is most suitable for a gas insulated conversion station. To increase this, it is necessary to take measures such as using a multipoint series configuration or using a long stroke. Become

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a high arc voltage, and to apply a small and economical gas circuit breaker to a bypass switch device suitable for a DC gas insulated conversion station. Is to provide.

[0014]

In order to achieve the above object, according to the present invention, a cutoff portion of a bypass switch is constituted by a high-pressure cutoff unit and a low-pressure cutoff unit which are electrically connected in series. The side shutoff unit is a dead tank type gas shutoff unit with a large tank diameter, the low pressure side shutoff unit is a dead tank type gas shutoff unit with a small tank diameter, and the high pressure side and low pressure side shutoff units are further characterized. It is characterized by adding a configuration driven by the same operating device, or a configuration in which the connection conductor of the interrupting unit is led out so as to be substantially parallel to the interrupting unit and the direction of the flowing current is opposite to each other. .

Further, the shut-off portion of the bypass switch is a dead tank type gas shut-off portion having a long stroke of one shut-off point, and the diameter of the tank is increased at the high pressure side portion and reduced at the low pressure side portion.

[0016] Further, the cutoff section of each bypass switch electrically connected in parallel to the stack group of each stage is composed of a high voltage side cutoff unit and a low voltage side cutoff unit electrically connected in series, The high pressure side cutoff unit connected to the high pressure side stack group is a dead tank type gas shutoff unit with a large tank diameter, connected to the low pressure side cutoff unit connected to the high pressure side stack group and the low pressure side stack group The high-pressure side cut-off unit and the low-pressure side cut-off unit to be used are characterized in that the tank diameter is the same and the dead tank type gas cut-off unit is small.

As described above, the present invention uses a dead tank type gas shut-off unit instead of the air shut-off unit as the shut-off unit of the bypass switch, so that the present invention is suitable for a DC gas insulated conversion station. Despite the use, the two high-voltage cut-off units and the low-voltage cut-off unit are electrically connected in series, so that a sufficiently high arc voltage can be generated. Since the tank diameter of each unit is reduced, the size of the apparatus can be reduced by that much, and the internal volume of the tank can be reduced to reduce the amount of gas used.

In addition, since a configuration is provided in which the high-pressure side and low-pressure side interrupting unit are driven by the same operating device, the number of operating devices can be reduced, or the interrupting unit and its connecting conductor can be substantially connected. Since a configuration is provided in which the electric current is led out in parallel and the directions of the flowing currents are opposite to each other, the arc can be extended by the electromagnetic repulsion between them, and the arc voltage can be further increased.

Further, since the dead tank type gas shut-off portion is set as one shut-off point of a long stroke, a sufficiently high arc voltage can be generated, and further, the tank diameter is partially changed so that the low pressure of the shut-off portion is reduced. Since the diameter of the tank portion accommodating the side is reduced, the size of the apparatus can be reduced by that much, and the internal volume of the tank can be reduced to reduce the amount of gas used.

Further, in the case of an apparatus comprising a plurality of bypass switches connected to a plurality of stack groups, only the high-pressure side cut-off unit of the cut-off unit of the bypass switch connected to the high-pressure side stack group is provided. The tank diameter is large, and the low pressure side cutoff unit of the bypass switch connected to the high pressure side stack group, and both the high pressure side and the low pressure side cutoff part of the bypass switch connected to the low pressure side stack group Since the diameters of the tanks of the unit are made small and the same, in addition to the above-described effects, the structure of the shut-off unit of these small-diameter tanks can be made common to facilitate their manufacture.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a front view showing a cross section of a part of a bypass switch according to an embodiment of the present invention. This bypass switch is connected to a high-pressure side thyristor valve stack group ST shown in FIG. It corresponds to the high-pressure side bypass switch BS.

In FIG. 1, reference numeral 10 denotes a large-diameter dead tank, and 11 denotes a small-diameter dead tank.
Numerals 0 and 11 are integrally connected to each other by tightening or welding the connecting portions 25 and 26 with bolts, and the high-pressure side drawing portion of the tank 10 is insulated by the insulating spacer 12 and the low-pressure side drawing portion of the tank 11 is insulated. The pressure chambers are hermetically sealed by spacers 13 and filled with SF ₆ gas to form an integral pressure vessel. In the large-diameter dead tank 10 of this pressure vessel, the high-pressure-side interrupting unit 1A of the interrupting unit 1A and the interrupting unit 1B electrically connected in series is housed. Is
The low-pressure-side cutoff unit 1B is stored. The structure of the interrupting unit 1A and the interrupting unit 1B are exactly the same, each is a puffer type interrupting unit, and the dimensions are only partially different. In the interrupting unit 1A, a fixed contact base 16 fixed to the inside of the tank 10 with the support insulator 15 and a fixed contact 17 electrically connected to the connection conductor 14
Is provided, and is opposed to the fixed contact 17 and is electrically connected to the connection conductor 18.
9A, a puffer piston 20 fixed to the other end of the tank is provided.
And a puffer cylinder 23 provided with an insulator nozzle 21 and a movable contact 22. The puffer cylinder 23 is connected to an operation device 33 via an insulating rod 30, a lever 31, and an operation rod 32.

In this embodiment, the breaking unit 1
Although A and the blocking unit 1B have the same size structure, the stroke length and the like may be different.

Breaker unit 1A side and breaker unit 1
The dimensional difference between the tanks 10 and 11
And the length of the connecting conductors 14 and 24, and the size of the supporting insulators 15 and 19B on the fixed contact side. The support insulator 15 having a long insulation distance is used on the high-voltage side interrupter unit 1A side, and the support insulator 19B having a short insulation distance is used on the low-voltage side interrupter unit 1B side. In addition, as for the size of the support insulator 19A on the movable contact side, one having a short insulation distance is used on any of the interruption unit units.

FIG. 1 shows a state in which the bypass switch is turned on. The direct current I is applied to the connection conductor 14... Fixed contact stand 16.
7: movable contact 22: puffer piston 20: flows into the low-voltage side cut-off unit 1B via the connection conductor 18, and similarly reaches the connection conductor 24 via the above-mentioned parts of the low-pressure side cut-off unit 1B.

When the stack group ST is activated, the operation device 33 is driven to drive the puffer cylinder 23 integrated with the movable contact 22 downward through the operation rod 32, lever 31, and insulating rod 30 in the drawing. I do. As a result, the movable contact 22 is separated from the fixed contact 17 and the arcs 3A, 3B are cut off by the respective breaker units 1A, 1B as shown in FIG.
B is generated. At the same time, the gas in the space surrounded by the puffer piston 20 and the puffer cylinder 23 is compressed, generating high-pressure gas. This high-pressure gas is blown to the arcs 3A and 3B via the insulator nozzle 21. With the stroke of the movable contact 22, the distance between the contacts increases, and the arc voltage increases almost linearly.

In FIG. 3, when the arc voltage in each of the interrupting units 1A and 1B electrically connected in series reaches or exceeds the minimum firing voltage of the bypass pair valve stacks a and d, the bypass pair valve stack a , D conduct. Furthermore,
By limiting the current by maintaining the arc voltage,
The entire current is commutated to the bypass pair valve stacks a and d to generate a current zero point and extinguish the arcs 3A and 3B. Only a low voltage of several hundred volts corresponding to the forward voltage drop of the bypass pair valve stacks a and d is applied between the bypass switches BS immediately after the cutoff.

After the bypass pair valve stacks a and d take over the entire current and the bypass switch BS extinguishes the arc and cuts off the current, the converter is controlled to gradually increase the output voltage (current). After several hundred milliseconds, the steady state is reached, and only at this point is the rated voltage applied between the bypass switches BS.

In this embodiment, the bypass switch BS
Since the dead tank type gas shut-off units 1A and 1B are used in place of the air shut-off unit as the shut-off unit, the present invention can be easily adapted to a DC gas insulated conversion station.

Moreover, the two cut-off unit units 1A and 1B
Are electrically connected in series to form two interruption points, so that an arc voltage that is twice as high as the arc voltage at one interruption point can be generated. The ignition and the arc are surely extinguished and the stack group ST can be reliably activated.

Further, since the diameter of the dead tank 11 and the supporting insulator 19B of the cut-off unit 1B are reduced, the size can be reduced by that much, and the internal volume of the tank can be reduced to reduce the amount of gas used.

In the above-described embodiment, the cut-off unit 1A, 1B has an operating device 33 independently. However, as shown in FIG. 4, the cut-off unit 1A and the lever 31 of the cut-off unit 1B are connected. Connect with rod 40,
It may be configured to be driven by one operating device 33. With this configuration, the number of operating devices can be reduced from two to one.

Further, it is not always necessary that the cut-off portion has two cut-off points, but may be one cut-off point as in the embodiment shown in FIG. In this case, the arc voltage can be made sufficiently high by making the stroke length of the breaking unit 1 at one breaking point several times longer than that of the AC circuit breaker. Further, in this embodiment, the diameter of the dead tank 41 is partially changed so that the diameter of the fixed contact 17 side of the blocking unit 1, that is, the tank portion 42 on the high pressure side is increased, and the movable contact of the blocking unit 1 is increased. The diameter of the tank portion 43 on the child side, that is, the low pressure side, is reduced. Further, the supporting insulator on the fixed contact 17 side is omitted. With such a configuration, the bypass switch BS
The size of the tank can be significantly reduced, and the amount of gas used can be reduced by reducing the internal volume of the tank.

FIG. 6 shows still another embodiment of the present invention. In this embodiment, each blocking unit 1
The central axes of one of the connection conductors 50 and 51 of A and 1B are substantially parallel to the central axes of the respective cutoff unit 1A and 1B, and the directions of the flowing currents are opposite to each other. In such a configuration, the fixed contact 1
When the movable contact 22 and the movable contact 22 are separated from each other and an arc is generated, the arc is repelled by the interaction of the current flowing through the connection conductors 50 and 51 with the magnetic field, so that the arc is opposite to the side where the connection conductors 50 and 51 are arranged. Driven. For this reason, the arc is elongated, the effective arc length is lengthened, and the arc voltage can be further increased.

Each of the above embodiments relates to the bypass switch BS connected to the stack group ST on the high voltage side, but one embodiment of the bypass switch BS 'connected to the stack group ST' on the low voltage side. The configuration is shown in FIG. In this embodiment, the small-diameter dead tank 1 shown in FIG.
A bypass switch BS 'is formed by electrically connecting two interrupting unit units 2A and 2B having the same size structure as the interrupting unit 1B housed in the unit 1 in series. Therefore, regarding each of the shutoff units 1A, 1B and 2A, 2B of the bypass switches BS and BS ', one shutoff unit 1A housed in the large-diameter dead tank 10 of the bypass switch BS and one of the shutoff units of the bypass switch BS are provided. One shut-off unit 1B housed in the small-diameter dead tank 11 and the shut-off units 2A and 2B housed in the small-diameter dead tank 11 of the bypass switch BS '.
Are two, and there are a total of three shut-off units housed in the small-diameter dead tank 11. Since these three units have the same size structure including the tank, they can be manufactured in common. It will be easier.

In each of the above embodiments, the shut-off portion is vertically arranged and the operation device is arranged at the lower portion. However, in the DC gas insulation system, the insulation deterioration due to the metal particles is much smaller than that of the AC. Because of the strict considerations,
As described above, by adopting the vertical arrangement in which the metal particles are unlikely to float, the diameter of the dead tank can be reduced as compared with the case of the horizontal arrangement. Therefore, if this point is not particularly taken into consideration, the blocking portion may be configured in a horizontal arrangement.

[0038]

As described above, according to the present invention, a dead tank type gas shut-off unit is used in place of an air shut-off unit as a shut-off unit of a bypass switch, so that it is suitable for a DC gas insulated converter. Despite the use of the gas cut-off section, the two cut-off points of the two cut-off sections electrically connected in series make it possible to generate a sufficiently high arc voltage. Since the diameter of the tank of the low-pressure side shut-off unit is reduced, the size of the apparatus can be reduced by that much, and the internal volume of the tank can be reduced to reduce the amount of gas used, which is economical.

Further, since the gas shut-off portion is set as one shut-off point of a long stroke, and the tank diameter of the tank is partially changed to make the diameter of the tank portion for storing the low-pressure side of the gas shut-off portion small, the arc voltage is sufficiently high. However, the apparatus can be downsized and the internal volume of the tank can be reduced to reduce the amount of gas used, which is economical.

Further, in a bypass switch device comprising a plurality of bypass switches connected to a plurality of stack groups, only the high pressure side cutoff unit of the bypass switch connected to the high pressure side stack group has a large tank diameter. In addition, the tank diameter of each of the low-pressure side cut-off unit of the bypass switch connected to the high-pressure side stack group and both the high-pressure side and the low-pressure side cut-off unit of the bypass switch connected to the low-pressure side stack group is reduced, and Since they are the same, in addition to the above-described effects, the structure of each shut-off unit having a small tank diameter can be shared to facilitate its manufacture, which is more economical.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a bypass switch according to an embodiment of the present invention.

FIG. 2 is a system diagram showing a basic configuration of a DC power transmission circuit.

FIG. 3 is a circuit diagram showing a configuration of a positive unipolar of a forward converter provided with a bypass switch.

FIG. 4 is a vertical sectional front view of a bypass switch according to another embodiment of the present invention.

FIG. 5 is a vertical sectional front view of a bypass switch according to still another embodiment of the present invention.

FIG. 6 is a vertical sectional front view of a bypass switch according to still another embodiment of the present invention.

FIG. 7 is a longitudinal sectional front view of a bypass switch according to still another embodiment of the present invention.

FIG. 8 is a vertical sectional front view of a conventional bypass switch.

[Explanation of symbols]

 ST, ST 'Thyristor valve stack group BS, BS' Bypass switch 1A, 1B, 2A, 2B Gas shut-off unit 10 Large-diameter dead tank 11 Small-diameter dead tank 18 Connection conductor 33 Operating device 40 Connecting rod 41 Dead tank 42 Large-diameter tank Part 43 Small diameter tank part 50, 51 Connection conductor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shunji Tokuyama 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Power & Electric Equipment Development Division (72) Inventor Keisho Endo Omika-cho, Hitachi City, Ibaraki Prefecture 7-2-1, Hitachi, Ltd. Power and Electricity Development Division (72) Inventor Kenichi Natsui 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Power and Electricity Development Division (72) Inventor Yoshito Asai 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside Hitachi Kokubu Plant, Hitachi, Ltd. (72) Inventor Tokio Yamagoku 1-1-1, Kokubuncho, Hitachi City, Hitachi, Ibaraki Hitachi, Ltd. Inside Kokubu Plant, Hitachi, Ltd. (72) Inventor Naoaki Takeji 3-3-22 Nakanoshima, Kita-ku, Osaka-shi, Osaka Inside Kansai Electric Power Company (72) Inventor Koji Takahata 2-5 Marunouchi, Takamatsu-shi, Kawasaki Prefecture Shikoku Electric Power Co., Inc. (72) Inventor Masayuki Hatano 6-15-1, Ginza, Chuo-ku, Tokyo Power development Co., Ltd. (56) References JP-A-7-105793 (JP) JP-A-8-36954 (JP, A) JP-A-5-49123 (JP, A) JP-A-5-342959 (JP, A) JP-A-58-69414 (JP, A) 54-12964 (JP, B2) Jiko 64-3147 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02B 13/02-13/075 H01H 33/59 H02J 1 / 00 301 H02M 7/155

Claims (5)

(57) [Claims] 1. A bypass switch device in which a bypass switch having an interrupting portion is electrically connected in parallel to a plurality of stack groups constituting a converter, wherein the interrupting portions of the bypass switch are electrically connected in series. A high-pressure side shut-off unit and a low-pressure side shut-off unit, the high-pressure side shut-off unit is a dead tank type gas shut-off unit having a large tank diameter, and the low-pressure side shut-off unit is a dead tank type having a small tank diameter. A bypass switch device comprising a gas shut-off unit. 2. The bypass switch according to claim 1, wherein the high-pressure side cut-off unit and the low-pressure side cut-off unit are driven by the same operating device. 3. The device according to claim 1, wherein at least one of the connection conductors of the high-voltage side cut-off unit and the low-voltage side cut-off unit is substantially parallel to the cut-off unit and the direction of the flowing current is opposite to each other. A bypass switch device characterized by being derived as follows. 4. A bypass switch device in which a bypass switch having a cut-off portion is electrically connected in parallel to a plurality of stack groups constituting a converter, wherein the cut-off portion of the bypass switch is connected to a long stroke one cut-off point. A dead tank type gas shut-off portion, wherein the tank diameter is large at the high pressure side portion and small at the low pressure side portion. 5. A bypass switch device in which a bypass switch having an interrupting portion is electrically connected in parallel to a plurality of stack groups constituting a converter, wherein the interrupting portions of the bypass switch are electrically connected in series. The high-pressure side shut-off unit composed of the high-pressure side shut-off unit and the low-pressure side shut-off unit connected to the high-pressure side stack group is a dead tank type gas shut-off unit having a large tank diameter, and the high-pressure side stack group. The low-pressure side shut-off unit connected to the low-pressure side stack group and the high-pressure side shut-off unit and the low-pressure side shut-off unit connected to the low-pressure side stack group have the same tank diameter and a small dead tank type gas shut-off unit. A bypass switch device characterized by the above-mentioned.