JPH0989963A - Dc high voltage generating device and its failure identifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC high voltage generating device and its failure identifying device in which a failure generating position can be easily specified, even when an abnormality occurs, without opening a metal vessel. SOLUTION: A multistage voltage double rectifier circuit 1 is housed in a metal vessel 2 having SF 6 gas sealed therein. An output terminal 14, an input terminal 13, and secondary winding terminals 5, 6 are provided on the outside of the metal vessel 2. The highest potential terminal 8 of the multistage voltage double rectifier circuit 1 is connected to the output terminal 14. Both ends of the secondary winding 4 of a boosting transformer 3 is connected to the secondary winding terminals 5, 6. The secondary winding terminals 5, 6 are short-circuited by a conductor, and an AC power source for failure judgment is connected between the secondary winding terminal 6 and the ground. The frequency and impedance of the input current are measured, whereby a ground position and a failing capacitor are examined.

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 using a multistage voltage doubler rectifier circuit housed in a metal container, and more particularly, to identify a fault in the multistage voltage doubler rectifier circuit. The present invention relates to a direct current high voltage generator suitable for the above and a fault identifying device therefor.

[0002]

Particle accelerators for accelerating charged particles such as electrons and ions to produce a particle beam of high kinetic energy are used for nuclear physics experiments, radiation chemistry, nondestructive inspection, food storage,
Widely used for cancer treatment. Among them, an accelerator that generates a high voltage by a multi-stage voltage doubler rectifier circuit such as a Cockcroft-Walton circuit that combines a large number of capacitors, diodes and transformers and accelerates it is widely used for industrial purposes as a simple DC high voltage generator. It's being used.

Since such a DC high voltage generator is required to be insulated from the ground, the entire multistage voltage doubler rectifier circuit is stored in a hermetically sealed container such as a metal tank in which an insulating medium is sealed. As the insulating medium, a highly insulating gas such as SF6 gas or insulating oil is used.

An example of the conventional DC high voltage generator as described above will be described below with reference to FIG. That is, a multistage voltage doubler rectifier circuit 1 including a large number of capacitors C and rectifiers D is stored in a metal container 2 in which SF6 gas is sealed. The highest potential terminal 8 of this multistage voltage doubler rectifier circuit 1 is
It is connected to an output terminal 14 provided outside the metal container 2. In addition, the multi-stage voltage doubler rectifier circuit 1 includes an input terminal 13 provided outside the metal container 2 via a boosting transformer 3.
It is connected to the. One end of the secondary side terminal of the step-up transformer is connected to the ground terminal 7 provided outside the metal container 2. An AC power supply 10 is connected to the input terminal 13, and the multistage voltage doubler rectifier circuit 1 is configured to use the AC power supply 10 as a power supply.

An example of the DC high-voltage generator having such a structure rectifies an AC voltage generated by the AC power source 10 on the secondary side of the step-up transformer 3 by using the multistage voltage doubler rectifier circuit 1 and outputs the rectified voltage. A high voltage direct current is generated between the terminal 14 and the ground.

[0006]

By the way, since the multistage voltage doubler rectifier circuit in the above DC high voltage generator is housed in the metal container, it is difficult to know the inside condition from the outside. . For this reason, not only in daily maintenance, but also when an abnormality occurs and it is necessary to identify the location of the failure, large-scale equipment and facilities are required for the internal point of view, and a lot of manpower and time are spent. Becomes

For example, when a metal container is filled with SF6 gas, in order to inspect the inside, a device for collecting the filled gas, a crane for catching the lid of the metal container, a container opened, Moisture-proof / dust-proof equipment (vinyl house, to prevent dust and humidity from entering the inside)
It was necessary to prepare dry air) and work for several days.

The present invention has been proposed in order to solve the problems in the prior art as described above, and its object is to open a metal container without opening it when an abnormality occurs in a DC high voltage generator. It is an object of the present invention to provide a direct current high voltage generator and a fault identification device therefor capable of easily identifying a fault occurrence location.

[0009]

In order to achieve the above object, the invention according to claim 1 is a secondary of a step-up transformer which is composed of a diode and a capacitor in a metal container filled with an insulating medium. A multi-stage voltage doubler rectifier circuit to which the side winding is connected, the output terminal to which the highest potential terminal of the multi-stage voltage doubler rectifier circuit is connected to the outside of the metal container, and the primary of the step-up transformer. A high-voltage direct current generator provided with an input terminal to which a side winding is connected, two ends of a secondary winding of the step-up transformer being connected to the outside of the metal container. A secondary winding terminal is provided.

In the invention according to claim 1 as described above, 2
Short-circuit the next winding terminal and connect an AC power supply between this terminal and ground. Then, the frequency and impedance of the input current are measured, and the position of the faulty capacitor is specified according to the equation indicating the impedance as a function of the frequency of the input current and the position of the capacitor.

According to a second aspect of the present invention, a multi-stage voltage doubler rectifier circuit, which is composed of a diode and a capacitor and to which a secondary winding of a step-up transformer is connected, is housed in a metal container filled with an insulating medium. On the outside of the metal container,
An output terminal connected to the highest potential terminal of the multistage voltage doubler rectifier circuit and an input terminal connected to the primary winding of the step-up transformer are provided, and are generated by the multistage voltage doubler rectifier circuit. In a failure identification device for a DC high-voltage generator that identifies such a failure, two secondary winding terminals, to which both ends of the secondary winding of the step-up transformer are connected, are provided outside the metal container. And a conductor that short-circuits the secondary winding terminal is connected, and an AC power supply having a clear frequency and a voltage that does not allow the forward current of the diode to flow between the secondary winding terminal and the ground. It is characterized by being connected.

In the above-described invention according to claim 2, in the state where the secondary winding terminal is short-circuited by the conductor, a voltage having a clear frequency by the AC power supply and a forward current of the diode does not flow is applied. When applied, the multi-stage voltage doubler rectifier circuit is considered similar to a capacitor-only circuit. Then, the impedance viewed from the AC power source is measured, and the position of the defective capacitor is specified in accordance with the equation showing the impedance as a function of the frequency of the input current and the position of the capacitor.

According to a third aspect of the present invention, in the fault identifying device for a DC high voltage generator according to the second aspect, a knowledge base that stores information associating an impedance with a fault state in the multistage voltage doubler rectifier circuit, It is characterized by further comprising: a determining unit that determines a failure state based on the measured value of the impedance and the information of the knowledge base.

According to the third aspect of the invention as described above, in the state where the secondary winding terminal is short-circuited by the conductor, a voltage having a clear frequency by the AC power supply and a forward current of the diode does not flow is applied. Apply. Then, the failure state is determined based on the knowledge base information by inputting the measured value of the impedance viewed from the AC power supply to the determination means.

According to a fourth aspect of the present invention, a multi-stage voltage doubler rectifier circuit, which is composed of a diode and a capacitor and to which a secondary winding of a step-up transformer is connected, is housed in a metal container filled with an insulating medium. On the outside of the metal container,
An output terminal connected to the highest potential terminal of the multi-stage voltage doubler rectifier circuit, an input terminal connected to the primary winding of the boosting transformer, and a secondary winding of the boosting transformer. In the fault identification device of the DC high-voltage generator for identifying a fault occurring in the multistage voltage doubler rectifier circuit, a load is connected to the output terminal, and the ground terminal and the ground are provided. And a DC power supply having the same polarity as the output of the multi-stage voltage doubler rectifier circuit are connected between and.

In the invention as described above, it is considered that the DC current is applied by the DC power supply and the multistage voltage doubler rectifier circuit is similar to the series circuit of the diodes. Then, gradually increase the voltage and measure the voltage at which conduction is obtained between the ground terminal and the highest potential terminal, and determine the voltage, the forward operating voltage of one diode, the number of diodes, and a short-circuited state due to a failure. Specify the number of failed diodes according to the formula that shows the relationship with the number of failed diodes.

According to a fifth aspect of the present invention, in the fault identifying apparatus for a high voltage DC generator according to the fourth aspect, when a current is passed through the multistage voltage doubler rectifier circuit by the direct current power source, the output terminal and the Judgment means for judging a failure state based on a knowledge base storing information associating a voltage at which a current starts flowing with a ground terminal and the number of failed diodes, and an actual measurement value of the voltage and information of the knowledge base. It is characterized by having and.

In the invention described in claim 5, when a direct current is applied from the direct current power source, the multistage voltage doubler rectifier circuit is regarded as a series circuit of diodes. Then, the voltage is gradually increased, the voltage at which conduction is obtained between the ground terminal and the highest potential terminal is measured, and is input to the determination means. Then, the number of failed diodes is specified by the determination means based on the input measured voltage and the knowledge base information.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments corresponding to the inventions described in claims 1 to 5 will be described below with reference to FIGS. The same members as those in the conventional technique shown in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted.

(1) First Embodiment First, one embodiment of a high voltage DC generator according to claim 1 will be described as a first embodiment below with reference to FIG. The present embodiment is a direct-current high-voltage generator that is the basis of the failure identification device according to the second and third embodiments described in (2) and thereafter.

(Structure) First, the structure of the present embodiment will be described. That is, both ends of the secondary winding 4 of the step-up transformer 3 which supplies an input to the multi-stage voltage doubler rectifier circuit 1 are connected to the secondary winding terminals 5 and 6 provided outside the metal container 2. The secondary winding terminal 6 is grounded and also serves as the ground terminal 7 of the multistage voltage doubler rectifier circuit 1. Both ends of the primary winding of the step-up transformer 3 are connected to the input terminal 13. The AC power supply 10 is connected to the input terminal 13 during normal operation.

(Operation) The operation and effect of the present embodiment having the above-mentioned configuration are as follows. That is, during normal operation, the AC power supply 10 causes
The AC voltage generated on the next side is rectified by using the multistage voltage doubler rectifier circuit 1 to generate a high-voltage DC between the output terminal 14 and the ground.

At the time of checking the condition of the capacitor, the AC power supply 10 for normal operation is removed and the secondary winding terminals 5 and 6 are connected.
Is short-circuited by a conductor, and an AC power supply for failure determination is connected between the secondary winding terminal 6 and the ground. Then, by measuring the frequency and impedance of the input current, the ground fault location and the faulty capacitor are examined. This operation will be described more specifically in the second embodiment (2).

When checking the state of the diode, the AC power supply 10 for normal operation is removed and the DC power supply 12 is connected between the ground terminal 7 and the ground. Then, by gradually increasing the voltage and measuring the voltage when conduction is obtained, the number of failed diodes is checked. This operation will be described more specifically in the third embodiment (3).

(Effect) The effects of the present embodiment as described above are as follows. That is, by short-circuiting the secondary winding terminals 5 and 6 and connecting an AC power supply for failure determination, the ground fault location and the failed capacitor can be easily examined. Further, by connecting the DC power supply 12, the number of failed diodes can be checked. Therefore, it is not necessary to open the metal container 2 by using a large-scale device or equipment for the inspection, and a lot of manpower and time are not consumed.

(2) Second Embodiment Failure of DC High Voltage Generating Device Corresponding to the Invention of Claim 2 One embodiment of the device is a second embodiment according to FIGS. This will be described below. The present embodiment is a device for inspecting the state of the capacitor in the DC high voltage generator, and the basic DC high voltage generator has the same configuration as that of the first embodiment.

(Configuration) First, the configuration of the present embodiment will be described. The conductor according to claim 2 is a high-voltage cable. That is, as shown in FIG. 2, the AC power supply 10 for normal operation in the first embodiment of FIG. 1 is removed, and the secondary winding terminals 5 and 6 are short-circuited by the high voltage cable 9. Then, an AC power supply 11 for failure determination is connected between the secondary winding terminal 6 and the ground. The AC power supply 11 applies a voltage having a clear frequency and at which the diode does not operate in the forward direction.

(Operation) The operation of the present embodiment having the above-described configuration will be described below in accordance with a procedure for identifying which capacitor has a circuit ground fault or which capacitor has a failure. To do. The multistage voltage doubler rectifier circuit 1 has n stages.

That is, the m-th and (m +
1) It is assumed that a ground fault occurs due to insulation failure or the like at point A between the capacitors. The electric circuit at this time is the same as the circuit having only the capacitor, and when the capacitance of the capacitor is C, it becomes as shown in FIG. The impedance of this circuit is a function of the frequency of the input power supply, as shown in Equation 1 below. In the formula 1, C
1 = (1 / n) C, C2 = (1 / m) C, C3 = {1 /
(Nm)} C.

[0030]

[Equation 1] Then, the frequency of the input current from the AC power supply 11 and the impedance seen from the AC power supply 11 are measured, and the value of m is obtained from the above equation 1 based on the measured values, so that the mth surface and the m + 1th surface from the high potential side A between the capacitors
It is specified at this point that a ground fault has occurred due to poor insulation.

It is also assumed that the m-th capacitor itself from the high-potential side has a failure and that part is in a ground fault state. The electric circuit at this time is as shown in FIG. When the impedance of this circuit is C1 = (1 / n) C and C3 = {1 / (n-m)} C in the above equation 1, and is replaced by C2 = {1 / (m-1)} C Since it is equal to, it is expressed by the following equation 2 and is also a function of the frequency of the input power supply.

[0032]

[Equation 2] Then, the frequency of the input current from the AC power supply 11 and the impedance seen from the AC power supply 11 are measured, and the value of m is obtained from the above formula based on the measured values, whereby the m-th capacitor itself from the high potential side fails. You can identify what you are doing.

(Effect) The effects of the present embodiment as described above are as follows. That is, if the frequency and impedance of the input current are measured, it is possible to identify which capacitor has the ground fault point or which capacitor has a failure by the above equations 1 and 2, so open the metal container. The failure can be easily and quickly identified without any trouble.

(3) Third Embodiment Failure of DC High Voltage Generating Device Corresponding to Invention of Claim 4 One embodiment of the device is a third embodiment according to FIGS. This will be described below. In this embodiment,
This is a device for inspecting the state of the diode in the DC high voltage generator, and the basic DC high voltage generator has the same configuration as that of the first embodiment.

(Configuration) First, the configuration of the present embodiment will be described. That is, as shown in FIG. 5, the AC power supply 10 for normal operation in the first embodiment of FIG. 1 is removed, and the DC power supply 12 is connected between the ground terminal 7 and the ground. The DC power supply 12 has the same polarity as the output of the multistage voltage doubler rectifier circuit 1. A load resistor 15 is connected between the output terminal 14 of the metal container 2 and the ground.

(Operation) The operation of the present embodiment having the above-mentioned structure will be described below in accordance with the procedure for checking the number of the failed diodes. The multistage voltage doubler rectifier circuit 1 has n stages.

That is, the voltage from the DC power source 12 is gradually increased starting from a low level, and the voltage V0 at which conduction is obtained between the input side terminal (here, the ground terminal 7) and the highest potential terminal 8 is measured. Since the input power source is direct current,
The impedance of the capacitor C becomes infinite and can be treated in the same way as the release, and the secondary winding 4 of the transformer can be treated as a conductor. The electric circuit at this time is, as shown in FIG. 6, a series connection of 2n diodes D.

Therefore, assuming that the operating voltage of one diode in the forward direction is V1, if all the diodes D are normal, they will conduct at 2 nV1. If the m number of diodes had a short-circuiting failure, (2n-
Since the equation of V0 / V1) = m holds, the number m of diode failures is estimated from this equation.

(Effects) The effects of the present embodiment as described above are as follows. That is, the number of failed diodes can be specified by the above equation from the voltage V0 at which conduction is obtained between the ground terminal 7 and the highest potential terminal 8 and the forward operating voltage of one diode from V1. The failure can be easily and quickly identified without opening the metal container.

(4) Other Embodiments The present invention is not limited to the above embodiments, and the size, number, etc. of each member can be changed as appropriate.
For example, the number of stages of the multi-stage voltage doubler rectifier circuit 1 is not particularly limited, and the number can be freely increased or decreased from the number described in the drawings.

Further, as one embodiment corresponding to the invention described in claims 3 and 5, the following can be constructed. That is, a computer is provided as the failure state determination means in the second and third embodiments. Then, an experiment was conducted by simulating the relationship between the measurement conditions such as impedance and the failure state in the second embodiment and the relationship between the measurement conditions such as the conduction voltage V0 and the failure state in the third embodiment. The obtained data at the time of failure is stored in the knowledge base of the computer. Then
When a failure occurs in the multi-stage voltage doubler rectifier circuit, by inputting the measurement result into the computer, it is possible to immediately determine the failure location or the like based on the knowledge base data.

If this computer is a small portable device such as a book type computer, it is possible to bring it to the DC high voltage generator when a failure occurs and determine the failure.

[0043]

As described above, according to the present invention, two secondary winding terminals to which both ends of the secondary winding of the step-up transformer are connected are provided outside the metal container. Thus, it is possible to provide a high-voltage DC generator and a fault identification device therefor, which can easily identify the location of failure when an abnormality occurs in the high-voltage DC generator.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a DC high voltage generator according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a fault identifying device for a DC high voltage generator according to a second embodiment of the present invention.

FIG. 3 is a diagram showing equivalent circuits (a) and (b) when a ground fault occurs between the capacitors in the embodiment of FIG.

FIG. 4 is a diagram showing equivalent circuits (a) and (b) when a capacitor fails in the embodiment of FIG.

FIG. 5 is a configuration diagram showing a DC high voltage generator according to a third embodiment of the present invention.

FIG. 6 is a diagram showing an equivalent circuit at the time of checking the state of the diode according to the embodiment of FIG.

FIG. 7 is a configuration diagram showing an example of a conventional DC high voltage generator.

[Explanation of symbols]

 1 ... Multi-stage voltage doubler rectifier circuit 2 ... Metal container 3 ... Boosting transformer 4 ... Secondary winding 5,6 ... Secondary winding terminal 7 ... Grounding terminal 8 ... Highest potential terminal 9 ... High voltage cable 10 ... During normal operation AC power supply 11 ... AC power supply for failure determination 12 ... DC power supply 13 ... Input terminal 14 ... Output terminal 15 ... Load resistance C ... Capacitor D ... Diode

Claims (5)

[Claims] 1. A multi-stage voltage doubler rectifier circuit comprising a diode and a capacitor and connected to a secondary winding of a step-up transformer is housed in a metal container filled with an insulating medium. A DC high voltage generator having an output terminal connected to the highest potential terminal of the multi-stage voltage doubler rectifier circuit and an input terminal connected to the primary winding of the step-up transformer on the outside. A DC high voltage generator, wherein two secondary winding terminals, to which both ends of a secondary winding of the step-up transformer are connected, are provided outside the metal container. 2. A multi-stage voltage doubler rectifier circuit, which is composed of a diode and a capacitor and to which a secondary winding of a step-up transformer is connected, is housed in a metal container filled with an insulating medium. An output terminal to which the highest potential terminal of the multistage voltage doubler rectifier circuit is connected and an input terminal to which the primary winding of the boosting transformer is connected are provided on the outside, and the multistage voltage doubler rectifier circuit is provided. In a failure identification device for a DC high-voltage generator for identifying a failure that has occurred in two, two secondary windings in which both ends of the secondary winding of the step-up transformer are connected to the outside of the metal container. A terminal is provided, a conductor short-circuiting the secondary winding terminal is connected, and a voltage having a definite frequency and a forward current of the diode does not flow between the secondary winding terminal and the ground. Characteristic that AC power supply is connected A fault identification device for a DC high voltage generator. 3. A determination of a failure state based on a knowledge base storing information associating an impedance and a failure state in the multi-stage voltage doubler rectifier circuit, and an actual measurement value of the impedance and information of the knowledge base. 3. A failure identification device for a DC high voltage generator according to claim 2, further comprising: 4. A multi-stage voltage doubler rectifier circuit, which is composed of a diode and a capacitor and to which a secondary winding of a step-up transformer is connected, is housed in a metal container filled with an insulating medium. An output terminal to which the highest potential terminal of the multistage voltage doubler rectifier circuit is connected, an input terminal to which a primary winding of the step-up transformer is connected, and a secondary side of the step-up transformer. And a ground terminal to which a winding of is connected is provided, in a failure identification device of a DC high-voltage generator for identifying a failure that has occurred in the multi-stage voltage doubler rectifier circuit, a load is connected to the output terminal, the ground A failure identifying apparatus for a DC high voltage generator, wherein a DC power supply having the same polarity as the output of the multistage voltage doubler rectifier circuit is connected between the terminal and the ground. 5. Information is stored that associates a voltage at which a current starts to flow between the output terminal and the ground terminal with the number of faulty diodes when a current flows through the multi-stage voltage doubler rectifier circuit by the DC power supply. 5. The fault identification of the DC high-voltage generator according to claim 4, further comprising: a knowledge base, and a determination unit that determines a fault state based on the measured value of the voltage and the information of the knowledge base. apparatus.