JPH0898532A - Polarity reversible dc high-voltage generation apparatus - Google Patents

Abstract

PURPOSE: To obtain a DC high-voltage generation apparatus in which a polarity reversing mechanism in a symmetrical circuit is made small and lightweight by a method wherein a rectifier bridge is driven lazy a drive gear, the connection of a contact point to an electrode plate for a smoothing-side capacitor is changed over and the polarity of an output voltage can be reversed. CONSTITUTION: A rectifier bridge 1 is turned by drive gears 8, 8' via transmission mechanisms 6, 6', the connection of contact points 5, 5' installed at both ends of the rectifier bridge 1 to electrode plates 10, 10' for a smoothing-side capacitor is changed over, and the polarity of an output voltage is reversed. That is to say, when the polarity of the output voltage is positive, the positive-side output terminal of the rectifier bridge 1 is connected to the high-voltage side of the smoothing-side capacitor 4, and the negative-side output terminal of the rectifier bridge 1 is connected to the low-voltage side of the smoothing-side capacitor 4. In addition, when the polarity of the output voltage is to be negative, a connecting operation in the reverse direction is performed, and the polarity of the output voltage can be reversed. Thereby, it is possible to obtain a DC high-voltage generation apparatus which is excellent in an electrical characteristic and which is small and lightweight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high voltage generator used for a withstand voltage test and a dielectric breakdown test of power cables and power transmission and transformation equipment.

[0002]

2. Description of the Related Art DC power transmission is used for power transmission over long-distance power cables such as submarine cables, and 1000 k is used for testing power cables for DC power transmission and transmission and transformation equipment.
A device that generates an ultra high DC voltage of V to 2000 kV is required, and the polarity is reversed in a short time even in a test device because the operation to reverse the polarity is performed during actual operation in a short time. Function is required.

In the conventional DC high-voltage generator, a device in which the entire device is insulated with insulating oil or high-pressure gas is manufactured for the purpose of downsizing and weight reduction. Of these, FIG. 2 (A)
There is a strong user's demand for a device of the symmetrical cascade circuit of FIG. 2 or the symmetrical inverse cascade circuit of FIG. 2B (hereinafter referred to as symmetrical circuit) and having a polarity reversing mechanism. Up to now, in a symmetrical circuit, the number of rectifiers is four times the number of stages and the circuit configuration is divided into two rows, so the mechanism for polarity reversal becomes complicated and large, and a device having a polarity reversal mechanism is oil-insulated or It was difficult to make high pressure gas insulation.

[0004]

The problem to be solved by the present invention is not suitable for reduction in size and weight due to oil insulation or high-pressure gas insulation because the polarity reversing mechanism is complicated and large in size. In the symmetrical circuit that has been developed, there are many user demands for the polarity reversing mechanism with a simple structure and small size and light weight, and it is to realize this.

In the above problems, the symmetrical circuit has a voltage drop when a load current flows, as compared with a Cockcroft-Walton circuit (hereinafter referred to as a CW circuit) of a conventional polarity reversal type DC high voltage generator. It has an excellent feature that the ripple voltage is small (Reference "Insulation Test Method Handbook", The Institute of Electrical Engineers of Japan, 1972, p30-p34). Also,
The input current waveform from the AC power source in the CW circuit is positive and negative asymmetric, whereas the symmetrical circuit is positive and negative symmetrical,
When a high frequency inverter circuit is used as the AC power source, there are the following advantages. One is that if the high frequency inverter circuit is made into a half bridge type or a full bridge type suitable for large output, the voltage and current waveforms applied to the two sets of output switching elements will be the same, and there will be no imbalance in electrical stress, which is economical. Another is that it is possible to select the appropriate switching elements and perform heat dissipation processing.The other is the high-frequency booster transformer that connects the high-frequency inverter circuit and the high-voltage circuit. There is no point.

[0006]

In order to reduce the size and weight of a polarity reversing mechanism in a symmetrical circuit having excellent characteristics, the present invention uses four rectifiers in each stage as one rectifier bridge,
This is a DC high voltage generator in which a rotating mechanism is provided for rotation so that the rectifying direction can be switched by the transmission mechanism and the driving device to reverse the polarity.

That is, according to the present invention, two rows of push-up side capacitors 2 connected in series from the high voltage terminal of the secondary winding of the transformer 13 and smoothing side capacitors 4 connected in multiple stages from the ground point 16 are provided. A symmetric or symmetrical inverse type cascade DC high voltage generator comprising rectifiers 11 connected in a staggered manner, each stage comprising a rectifier bridge 1 having contact points 5, 5'at both ends and a rotating mechanism 3 at an intermediate point. In preparation for this, the rectifier bridge 1 at each stage is provided with transmission mechanisms 6 and 6 ′ for connecting the respective rectifier bridges, and drive devices 8 and 8 ′ for driving the rectifier bridges. 1 is a polarity reversal type DC high voltage generator capable of reversing the polarity of the output voltage by driving 1 to switch the connection between the contact points 5 and 5'and the electrode plates 10 and 10 'of the smoothing side capacitors.

[0008]

The rectifier bridge 1 is rotated by the drive units 8 and 8'via the transmission mechanisms 6 and 6 '.
The polarity of the output voltage is inverted by switching the connection between the contact points 5 and 5'provided at both ends of the electrode and the electrode plates 10 and 10 'of the smoothing side capacitor. That is, when the polarity of the output voltage is positive, the positive output terminal of the rectifier bridge 1 is connected to the high voltage side of the smoothing capacitor 4, and the negative output terminal of the rectifier bridge 1 is connected to the low voltage side of the smoothing capacitor 4. Connected. When the polarity of the output voltage is negative, the polarity of the output voltage can be reversed by performing the operation of connecting in the opposite direction.

[0009]

FIG. 1 is a structural diagram of an embodiment of the present invention,
1 is a rectifier bridge, 2 is a pushing-up side condenser, 3 is a rotating mechanism, 4 and 4'are smoothing side condensers, 5 and 5'are contact points, 6 and 6'are transmission mechanisms, 7 and 7'are insulating support insulators,
8 and 8'is a drive device, 9 is an electrode plate of the pushing-up side capacitor, 10 and 10 'are electrode plates of the smoothing side capacitors, 11 is a rectifier, 12 and 12' are switches, 13 is a transformer, 14
Is an AC power supply, 15 is a load, and 16 is a ground point.

In the above, the electrode plates 10 and 10 'of the smoothing-side capacitors having the same height are connected in parallel to each other,
The smoothing capacitors 4 and 4'of the same stage are electrically integrated, and the output voltage is taken out from the electrode plate of the smoothing capacitor of the uppermost stage. Further, each of the four rectifiers 11 forming the rectifier bridge 1 is formed by connecting a plurality of rectifying elements in series.

In the state shown in FIG. 1, the piston of the drive unit 8 is pushed out, and the positive output terminal of the rectifier bridge 1 connects the contact point 5 and the electrode plate 10 of the smooth side capacitor to the high voltage side terminal of the smooth side capacitor 4. The negative side output terminal of the rectifier bridge 1 is connected to the contact point 5 ′ on the low voltage side of the smoothing side capacitor 4 ′ and the electrode plate 10 ′ of the smoothing side capacitor. The circuit at this time becomes the circuit of FIG. 2, and the output voltage polarity of the device is positive. On the other hand, if the piston of the pneumatic cylinder 8'is pushed out contrary to FIG. 1, it means that the two switches 12 and 12 'in the circuit diagram of FIG. 3 are switched, and the output voltage polarity of the device is negative. Become.

2 and 3 are circuit diagrams, the polarity of the rectifier 11 at each stage in the symmetrical cascade type circuit example shown in FIG. 2 is switched to invert the output voltage polarity of the device. This can be explained by switching each polarity of the rectifier bridge by the switches 12 and 12 'as shown in FIG. That is, the configuration of the switch for polarity reversal is the most characteristic of the present invention.

The polarity reversal type DC high voltage generator of the present invention can be housed in a container to be oil-insulated or gas-insulated, and naturally, it can be used as an air-insulated device.

【The invention's effect】

According to the present invention, it becomes possible to mount a simple and small-sized and lightweight polarity reversing mechanism on a DC high-voltage generator which is constituted by a symmetrical circuit, which has been conventionally considered unsuitable for downsizing, and has an electrical characteristic. It is possible to provide a DC high-voltage generator that is excellent in size and weight, and is industrially and practically valuable.

[Brief description of drawings]

1A and 1B are structural diagrams of an embodiment of a polarity reversal type DC high voltage generator of the present invention,
(A) is a plan view and (B) is a side view.

2A and 2B show a known symmetrical type and symmetrical inverse type cascade DC high voltage generator, in which FIG. 2A is a symmetrical type and FIG. 2B is a symmetrical inverse type circuit.

FIG. 3 is a circuit diagram for explaining polarity inversion of a rectifier bridge, which is an essential part of the present invention.

[Explanation of symbols]

 1 Rectifier Bridge 2 Push-Up Side Capacitor 3 Rotation Mechanism 4, 4'Smoothing Side Capacitor 5, 5 'Contact Point 6, 6'Transmission Mechanism 7, 7' Insulation Support Insulator 8, 8'Drive Device 9 Push-Up Side Capacitor Electrode Plate 10 10 'Smoothing-side capacitor electrode plate 11 Rectifier 12, 12' switch 13 Transformer 14 AC power supply 15 Load 16 Ground point

Claims (1)

[Claims] 1. A two-row push-up side capacitor (2) connected in series from a high voltage terminal of a secondary winding of a transformer (13) and a smoothing side capacitor (4) connected in series from a ground point (16). ) And a rectifier (11) connected in a zigzag pattern thereto, which is a symmetrical or symmetrical inverse type cascade DC high voltage generator having contact points (5, 5 ′) at both ends and a rotating mechanism at an intermediate point. A rectifier bridge (1) having (3) is provided in each stage, and the rectifier bridge (1) in each stage has a transmission mechanism (6, 6 ') connecting the rectifier bridges and a drive device for driving the same. (8,
8 '), and driving the rectifier bridge (1) by a driving device (8, 8') to connect the contact point (5, 5 ') to the electrode plate (10, 10') of the smoothing side capacitor. Switch
Polarity reversal type DC high voltage generator capable of reversing the polarity of output voltage.