JP2000035457A - High voltage test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To verify interface insulation easily and simply without impressing higher voltage than voltage to ground by impressing antiphase power of 50% of fixed power on power conductors of the other two phases, when fixed voltage is impressed on a power conductor of one phase of a three-phase package electrical machinery and apparatus. SOLUTION: Fixed voltage V is generated between the terminals U-E on the secondary side of a transformer 1 for testing the single phase. At this time, because voltage V/2 is generated between the terminals V-E on the secondary side, and the exciting direction of a coil is reverse, it becomes voltage of different phase by 180 degrees. Then the voltage V of the U-terminal is impressed on the R-phase impressed terminal 3a of a three-phase batch electrical machinery and apparatus 2 through an impressing line 4a, simultaneously with it, the voltage V/2 of the V-terminal is respectively impressed on a S-phase impressed terminal 3b and a T-phase impressed terminal 3c through an impressing line 4b. Hereby, the voltage V is impressed between the terminal 3a and the chest of the machinery and apparatus 2, the voltage V/2 of antiphase is impressed between the terminals 3b, 3c and the chest, and voltage V+(-V/2) is impressed between the terminal 3a and the terminals 3b, 3c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage test method which contributes to improving the reliability of insulation of an electric device containing three-phase conductors.

[0002]

2. Description of the Related Art FIG. 6 shows, for example, JEC-2350-199.
FIG. 5 is a diagram for explaining the conventional high voltage test method shown in FIG. In the drawing, 1 is a single-phase test transformer, 2 is a three-phase batch electric device containing three-phase conductors collectively, and 3 is a single-phase test transformer through a conductor 4 contained in the three-phase collective electrical device 2 through an application wire 4. 1 is an application terminal for applying a test high voltage. FIG.
FIG. 7 is a diagram showing a distribution of lines of electric force when a voltage is applied to each of the application terminals 3a, 3b, 3c shown in FIG. In the figure, reference numeral 7 denotes lines of electric force generated around the charging unit 5 in the closed container 6.

FIG. 7 is a voltage waveform showing a temporal change of a voltage applied from the single-phase transformer 1 shown in FIG. FIG. 9 is a voltage waveform showing a temporal change of the three-phase AC voltage when a three-phase AC voltage is actually applied to each application terminal.

Next, a high voltage test method will be described. Three
In a state where the application terminals S (3b) and T (3c) of the phase collective electric device 2 and the closed container 5 are grounded, the application terminal R
(3a) A high voltage is applied from the single-phase test transformer 1 through the application line 4. And the applied terminal R
Insulation between (3a) and the grounded application terminal S (3b), between the application terminals T (3c), or between the closed containers 6 is verified.

[0005]

The conventional high voltage test is:
As described above, in order to verify the insulation between phases, it is necessary to apply a voltage higher than the ground voltage to the application terminal. That is, taking a 550 kV transmission system as an example,
The line voltage between S phases (same between S and T and between T and R) is 55
To achieve 0 kV _RMS , a voltage of the R phase (same for the S phase and the T phase) is applied. This voltage is the voltage between the R phase and the closed container, and the ground is 550 / √3 = 318 kV.
_It is called _RMS voltage. At this time, the voltage phase of the S phase (same for the T phase) is shifted by 120 °, so that the ground voltage is reduced by half to 3
The voltage is 18 kV / 2.

Here, if a test voltage is applied by a conventional test method in which a voltage is applied to one terminal and the other terminal and the sealed container are grounded, for example, a line voltage of 5% is applied to the R phase.
When 50 kV is applied, the insulation between the R and S phases (at the same time, between the R and T phases) is verified as proper insulation. However, between the R phase and the closed container, 1.73 of 318 kV which is the original ground voltage is applied.
The doubled voltage is applied, and there is a possibility that serious damage may be caused to the ground.

Further, the applied voltage of the R phase is changed to a ground voltage (318 k
V), the voltage between the R phase and the S phase is similarly 318 KV, and is not applied to the normal voltage of 550 kV.
This is not a valid verification of insulation. Further, it is apparent that the electric field distribution (FIG. 8) in the voltage application mode of the conventional test method is different from the electric field distribution (FIG. 5) at the time of actual use (FIG. 9) and does not correspond to the actual use. Therefore, there is a problem that the conventional high voltage test method is not a method for verifying insulation properties corresponding to actual use.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a simple and simple method of applying a voltage distribution between phases without applying a voltage higher than a ground voltage, and in accordance with an actual use state. It is an object of the present invention to provide a high-voltage test method capable of verifying proper insulation using a phase test transformer.

[0009]

According to a first aspect of the present invention, there is provided a high-voltage test method for performing an AC high-voltage test on an insulated electric device in which power conductors corresponding to respective phases are housed in a single closed container while maintaining insulation. When performing the test, when a predetermined voltage is applied to the power conductor of one phase by the test transformer, a voltage of 50% of the predetermined voltage is simultaneously applied to the power conductors corresponding to the other two phases in opposite phases. It is something to do.

[0010] The high voltage test method according to the invention of claim 2 comprises:
A neutral point is provided on the secondary winding of the test transformer where the winding ratio is 1: 2, and the voltage generated from the winding having the winding ratio of 2 is applied to the power conductor of one phase. Then, voltages of opposite phases generated by windings having a winding ratio of 1 are simultaneously applied to power conductors corresponding to the other two phases.

According to a third aspect of the present invention, there is provided a high voltage test method comprising:
Two transformers having the same primary-side voltage specification and a proportional relationship of 1: 2 for each secondary-side voltage specification are provided as test transformers. The generated voltage is applied to the power conductor of one phase, and the opposite-phase voltage generated from the transformer having the secondary voltage specification of 1 is simultaneously applied to the power conductors corresponding to the other two phases. Things.

According to a fourth aspect of the present invention, there is provided a high voltage test method comprising:
As the test transformer, each primary side voltage specification is the same,
Provide three transformers with the same
The secondary windings of one transformer are cascaded, and the voltage generated in the cascaded windings is applied to the power conductor of one phase, and is generated in the secondary winding of another transformer. In this configuration, voltages of opposite phases are simultaneously applied to power conductors corresponding to the other two phases.

According to a fifth aspect of the present invention, there is provided a high voltage test method comprising:
The input terminals of the input voltage to the primary side are reversed and connected by the first and second transformers.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1
Sets the division ratio of the secondary winding to 2: 1 and the generated voltage ratio to 2: 1
A single-phase test transformer having a divided part of the secondary winding as a ground terminal; a two-phase electrical device containing three-phase conductors; Terminal for applying a test high voltage from the transformer 1 for testing.

Next, the operation will be described. A predetermined voltage V is generated between the terminals UE on the secondary side of the single-phase test transformer 1. At this time, the terminal U is simultaneously connected between the terminals VE on the secondary side.
Since a voltage V / 2, which is half of the voltage V between -E, is generated, and the exciting direction of the winding is opposite, the voltages have a phase difference of 180 °. The voltage V at the U terminal is applied to the application terminal R (3a) of the three-phase electric device 2 via the application line 4a, and the voltage V / 2 of the V terminal is simultaneously applied to the three-phase electric device 2 via the other application line 4b. The voltage is applied to the application terminals S (3b) and T (3c) of the electric device 2.

With this arrangement, the voltage between the application terminal R (3a) and the sealed container 6 is V, and the voltage between the application terminal S (3b) and the application terminal T (3c) and the sealed container 6 is V / 2 is applied, and the application terminal R (3a) and the application terminal S (3
b) and the voltage between the application terminal T (3c) and V + (− V /
2) is applied, and a voltage suitable for the actual phase can be applied between the phases without applying an excessive voltage between the ground, and valid insulation between the phases can be verified.

Embodiment 2 FIG. In the above-described embodiment, an example is shown in which one transformer in which the secondary side winding ratio is divided by 2: 1 is used as the single-phase test transformer. And the voltage ratio on the secondary side is 2: 1
, Two single-phase test transformers may be used.
At this time, if the primary-side input of one single-phase test transformer is connected in the opposite direction in order to reverse the excitation direction, the voltage will be 180 ° different in phase, and the same effect will be obtained. can get.

According to FIG. 2, the single-phase test transformers 1a, 1
The specifications of the primary winding of b are similar and are connected to a single high voltage source. The winding ratio of the secondary winding of the single-phase test transformers 1a and 1b is 2: 1. The voltage V between the U1 and V1 terminals is applied to the application terminal R (3a) of the three-phase collective electric device 2 via the application line 4a, and at the same time, the voltage V / 2 between the U2 and V2 terminals is applied to the other application line 4b. Via the three-phase electrical equipment 2
Are applied to the application terminals S (3b) and T (3c).

In the first embodiment, a transformer having a special structure having two high-voltage terminals and one ground terminal on the high-voltage side of the test transformer is required. A simple method using two transformers with the same specifications and a voltage ratio of 2: 1 on the secondary side will be described.

Embodiment 3 In the second embodiment, a simple method using two single-phase test transformers having a secondary side voltage ratio of 2: 1 is used. It is necessary that the turns ratio between them is 2: 1. In the present embodiment, three single-phase test transformers having the same primary-side specification and the same secondary-side specification are used, and the secondary windings of two of the single-phase test transformers are used. The same effects as in the second embodiment can be obtained even if the cascade connection is performed.

FIG. 3 is a diagram for explaining the high voltage test method according to the present embodiment. As shown in the figure, single-phase test transformers 1a1, 1a having the same specifications for both the primary voltage and the secondary voltage.
2, 1a3. The primary windings of the single-phase test transformers 1a1 and 1a2 are connected to a high voltage source to apply a high voltage of, for example, 6600v. The voltage V / 2 (for example, 500 kV) at the U3 terminal of the secondary winding of the single-phase test transformer 1a2 is applied to the application terminal S (3
b) and T (3c).

On the other hand, in the secondary winding of the single-phase test transformer 1a1, a U2 terminal and a U2 terminal where a high voltage of 6600 V is generated.
_{The 2V} terminal is connected to the primary winding of the single-phase test transformer 1a3, U1 in the secondary winding of the single-phase test transformer 1a3.
The terminal is connected to the application terminal R (3a) of the three-phase collective electric device 2 via the application line 4a. The V1 terminal of the secondary winding of the single-phase test transformer 1a3 is connected to the U2 terminal of the secondary winding of the single-phase test transformer 1a1.

At this time, since the V2 terminal of the secondary winding of the single-phase test transformer 1a1 is grounded, the secondary winding of the single-phase test transformer 1a3 and the secondary winding of the single-phase test transformer 1a1 The winding is connected in cascade. As a result, the voltage V (for example, 1) of the U1 terminal in the secondary winding of the single-phase test transformer 1a3.
000 kV) is applied to the application terminal R (3a) of the three-phase batch electric device 2 via the application line 4a.

The present embodiment is a method of using three test transformers of the same specification which are universally present as three-stage cascade connection test transformers, so that the method is easier than in the second embodiment. Test equipment can be provided.

[0025]

According to the first aspect of the present invention, when performing an AC high voltage test on an insulated electric device in which power conductors corresponding to each phase are housed in one closed container while maintaining insulation, a test transformer is used. When a predetermined voltage is applied to the power conductor of one phase at
Since 50% of the predetermined voltage is applied simultaneously to the power conductors corresponding to the three phases in opposite phases, it is possible to easily and easily verify the inter-phase insulation of the three-phase electrical equipment in a state according to the actual situation. Since the verification can be performed, there is an effect that the reliability of the electric device can be improved.

According to the second aspect of the present invention, a neutral point is provided in the secondary winding of the test transformer at a turn ratio of 1: 2, and a neutral point is provided at a turn ratio of 2: The generated voltage is applied to the power conductor of one phase, the voltage is generated from the winding having the winding ratio of 1, and the opposite phase voltage is simultaneously applied to the power conductors corresponding to the other two phases. There is an effect that two types of test voltages can be generated by a single transformer.

According to the third aspect of the present invention, as the test transformer, two transformers having the same primary-side voltage specification and having a proportional relationship of 1: 2 between the respective secondary-side voltage specifications are provided. The voltage generated from the transformer having the secondary voltage specification of 2 is applied to the power conductor of one phase, and the opposite phase voltage generated from the transformer having the secondary voltage specification of 1 is applied to the other two phases. Are applied simultaneously to the power conductors corresponding to the above-described configuration, and there is an effect that a test transformer capable of generating two kinds of test voltages can be configured by combining a transformer having a simple configuration.

According to the fourth aspect of the present invention, three transformers having the same primary-side voltage specifications and the same secondary-side voltage specifications are provided, and the secondary windings of the two transformers are provided. In cascade,
The voltage generated in the cascade-connected windings is applied to the power conductor of one phase, and the voltage of the opposite phase generated in the secondary winding of the other one transformer is converted to power corresponding to the other two phases. Since the voltage is applied to the conductors at the same time, there is an effect that a test transformer capable of generating two kinds of test voltages by a combination of transformers having the same voltage specification can be configured at lower cost.

According to the fifth aspect of the present invention, since the input terminals of the input voltage to the primary side are connected in reverse by the first and second transformers, the generation of the reverse phase voltage is prevented. This has the effect of being easier.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a circuit showing a high voltage test method according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a circuit showing another embodiment of the present invention.

FIG. 3 is a conceptual diagram of a circuit showing another embodiment of the present invention.

FIG. 4 is a diagram showing an AC voltage waveform applied to the three-phase collective electric device according to the present invention.

FIG. 5 is a diagram showing an electric field distribution applied to the three-phase collective electric device according to the present invention.

FIG. 6 is a conceptual diagram of a circuit showing a conventional high voltage test method.

FIG. 7 is a diagram showing an AC voltage waveform applied to a three-phase batch electric device by a conventional high-voltage test method.

FIG. 8 is a diagram showing a distribution of an electric field applied to a three-phase electric device by a conventional high-voltage test method.

FIG. 9 is a diagram showing an AC voltage waveform applied to an actual three-phase collective electric device.

[Explanation of symbols]

1a, 1a1, 1a2, 1a3, 1b Single-phase test transformer, 2 / 3-phase electrical equipment, 3a, 3b application terminal, 4a, 4b application wire, 5 charging exposed part, 6 closed container.

Claims (5)

[Claims] When conducting an AC high voltage test on an insulated electrical device in which power conductors corresponding to each phase are housed in a single closed container while maintaining insulation, a power transformer for one phase is applied to a power conductor of one phase by a test transformer. Wherein a voltage of 50% of the predetermined voltage is applied simultaneously to the power conductors corresponding to the other two phases in opposite phases. 2. A test transformer is provided with a neutral point on the secondary winding at a turn ratio of 1: 2, and applies a voltage generated from a winding having a turn ratio of 2 to one phase. 2. The power conductor according to claim 1, wherein the negative voltage is applied to the power conductors corresponding to the other two phases at the same time. Voltage test method. 3. As a test transformer, the primary side voltage specifications are the same, and the proportional relation between the secondary side voltage specifications is 1: 2.
A transformer is provided, and a voltage generated from a transformer having a secondary side voltage specification of 2 is applied to a power conductor of one phase, and an opposite phase generated from the transformer having a secondary side voltage specification of 1 is provided. The high voltage test method according to claim 1, wherein a voltage is simultaneously applied to power conductors corresponding to the other two phases. 4. Three transformers having the same primary-side voltage specifications and the same secondary-side voltage specifications are provided, and the secondary windings of the two transformers are cascade-connected. The voltage generated in the connected winding is applied to the power conductor of one phase, and the voltage of the opposite phase generated in the secondary winding of another transformer is applied to the power conductor corresponding to the other two phases. The high voltage test method according to claim 1, wherein the voltage is applied simultaneously. 5. The high voltage test method according to claim 3, wherein the input terminals of the input voltage to the primary side are connected in reverse by the first and second transformers. .