JP3164477B2 - Polarity inversion type DC high voltage generator - Google Patents

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, a dielectric breakdown test and the like of a power cable and a transmission / substation device.

[0002]

2. Description of the Related Art DC power transmission is used for power transmission over long-distance power cables such as submarine cables.
A device that generates a DC super high voltage of 2000 kV from V is required, and the polarity of the DC power transmission is reversed in a short time during the actual operation. Function is required.

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

[0004]

The problem to be solved by the present invention is that the polarity reversing mechanism is conventionally complicated and large, and thus is not suitable for reduction in size and weight by oil insulation or high pressure gas insulation. In the conventional symmetrical circuit, the polarity reversing mechanism has a simple structure and a small size and light weight, but there are many demands from users, and this is to be realized.

In the above-mentioned problem, the symmetrical circuit has a voltage drop when a load current flows, compared to a Cockcroft-Walton circuit (hereinafter referred to as a CW circuit) of a conventional polarity inversion type DC high voltage generator. There is an excellent feature that the ripple voltage is small (refer to "Insulation Test Method Handbook", IEEJ, Showa 46, p30-p34). Also,
The input current waveform from the AC power supply in the CW circuit is positive / negative asymmetric, while the symmetrical circuit is positive / negative symmetric,
When a high-frequency inverter circuit is used for the AC power supply, there are the following advantages. First, if the high-frequency inverter circuit is 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, and economy Another reason is that the high-frequency step-up transformer that connects the high-frequency inverter circuit and the high-voltage circuit causes the magnetic material to saturate due to the imbalance of the current. There is no point.

[0006]

According to the present invention, in order to reduce the size and weight of the polarity reversing mechanism in a symmetrical circuit having excellent characteristics, the four rectifiers in each stage are replaced by one rectifier bridge.
This is a DC high-voltage generator in which a rotating mechanism is provided so as to be rotatable, and the rectification direction is switched by a transmission mechanism and a driving device so that the polarity can be reversed.

That is, the present invention relates to a two-stage booster-side capacitor 2 connected in multiple stages from a high voltage terminal of a secondary winding of a transformer 13, a smoothing-side capacitor 4 connected in multiple stages from a ground point 16, and a rectifier 11 Metropolitan symmetrical or symmetrical inverse shaped cascade DC high-voltage generator consists of connected in a staggered manner, and the contact points 5 and 5 'at both ends, press
Each stage is provided with a rectifier bridge 1 composed of four rectifiers having a rotation mechanism 3 at an intermediate point which is a connection point of the lifting-side capacitor 2 , and each rectifier bridge 1 is connected to each rectifier bridge 1. Transmission mechanism 6, 6 'and this
Drives 8, 8 'driven by pneumatic cylinder pistons
The provided, the driving device 8, 8 'by driving the rectifier bridge 1, the contact points 5 and 5' to switch the connection between the electrode plates 10, 10 'of the smoothing side capacitor and can reverse the polarity of the output voltage This is a polarity inversion type DC high voltage generator.

[0008]

The rectifier bridge 1 is rotated by the driving devices 8, 8 'via the transmission mechanisms 6, 6'.
Of the output voltage by switching the connection between the contact points 5, 5 'provided at both ends of the electrode and the electrode plates 10, 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 set to be negative, the polarity of the output voltage can be inverted by performing an operation of connecting in the opposite direction.

[0009]

FIG. 1 is a structural view of an embodiment of the present invention.
1 is a rectifier bridge, 2 is a push-up capacitor, 3 is a rotating mechanism, 4 and 4 'are smoothing capacitors, 5 and 5' are contact points, 6 and 6 'are transmission mechanisms, 7 and 7' are insulating support insulators,
Reference numerals 8 and 8 'denote driving devices, 9 denotes an electrode plate of a push-up capacitor, 10 and 10' denote electrode plates of a smoothing capacitor, 11 a rectifier, 12 and 12 'switches, 13 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 capacitor having the same height are connected in parallel with each other,
The smoothing-side capacitors 4 and 4 'in the same stage are electrically integrated, and an output voltage is extracted from the electrode plate of the uppermost-stage smoothing-side capacitor. Each of the four rectifiers 11 constituting the rectifier bridge 1 has a plurality of rectifiers connected in series.

In the state shown in FIG. 1, the piston of the driving device 8 is pushed out, and the positive output terminal of the rectifier bridge 1 is connected to the high voltage terminal of the smoothing capacitor 4 by the contact point 5 and the electrode plate 10 of the smoothing capacitor. The negative output terminal of the rectifier bridge 1 is connected to the contact point 5 'on the low voltage side of the smoothing capacitor 4' and the electrode plate 10 'of the smoothing capacitor. The circuit at this time is the circuit shown in FIG. 2, and the output voltage polarity of the device becomes positive. On the other hand, if the piston of the pneumatic cylinder 8 'is pushed out contrary to FIG. 1, 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.

In the circuit diagram, FIG. 2 and FIG. 3 are explanatory diagrams described above. In the circuit example of the symmetrical cascade type circuit shown in FIG. 2, the polarity of the rectifier 11 at each stage 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 reversing type DC high voltage generator of the present invention can be housed in a container to be oil-insulated or gas-insulated, or of course can be used for air insulation.

【The invention's effect】

According to the present invention, it is possible to mount a simple, small, and lightweight polarity reversal mechanism on a DC high voltage generator constituted by a symmetrical circuit which has been considered unsuitable for miniaturization. It is possible to provide a compact and lightweight DC high-voltage generator excellent in industrial and practical applications.

[Brief description of the drawings]

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

FIGS. 2A and 2B are known symmetrical and symmetrical inverse cascade DC high-voltage generators. FIG. 2A shows a symmetrical type, and FIG. 2B shows a symmetrical inverse type circuit.

FIG. 3 is a circuit diagram illustrating polarity inversion of a rectifier bridge, which is a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectifier bridge 2 Push-up capacitor 3 Rotating mechanism 4, 4 'Smooth-side capacitor 5, 5' Contact point 6, 6 'Transmission mechanism 7, 7' Insulating support insulator 8, 8 'Driving device 9 Electrode plate of push-up capacitor 10 , 10 'Electrode plate of smoothing side capacitor 11 Rectifier 12, 12' Switch 13 Transformer 14 AC power supply 15 Load 16 Grounding point

Claims (1)

(57) [Claims] 1. A two-stage boost-side capacitor (2) connected in multiple stages from a high voltage terminal of a secondary winding of a transformer (13) and a smoothing-side capacitor (4) connected in multiple stages from a ground point (16). ) And a rectifier (11) connected in a zigzag pattern to the symmetrical or symmetrical inverse cascade DC high voltage generator, having contact points (5, 5 ′) at both ends and a booster capacitor (2). ) Connection point
Four rectifiers with a rotation mechanism (3) at the midpoint
Comprising rectifier bridge (1) in each stage consisting of a rectifier bridge (1) of each stage, and the transmission mechanism for connecting the respective rectifier bridge (6, 6 '), pneumatic cylinder it
A drive device (8, 8 ') driven by the piston of the damper,
The driving device (8, 8 ') drives the rectifier bridge (1) to switch the connection between the contact points (5, 5') and the electrode plates (10, 10 ') of the smoothing-side capacitor, and to output voltage Polarity inversion type DC high voltage generator that can invert the polarity of