JPH0618587A - Method for applied voltage test of dc power cable - Google Patents

Abstract

PURPOSE:To carry out both of applied voltage tests by using a direct current, since the conventional applied voltage tests use alternating currents for continuity, where as the test is for direct current, and there is a possibility of occurring such a case that evaluated results do not reflect those of actual lines. CONSTITUTION:By using, for example, an auxiliary cable 20 prepared separately from a sample cable 14, an alternating current is made to flow through the auxiliary cable 20 through a current transformer 18 and the alternating current is converted into a direct current by means of a half-wave rectifier 22. Then the direct current is made to flow through the sample cable 14. It is possible to eliminate the need of the cable 20 when a closed circuit is formed by short-circuiting both ends of the cable 14 through a conductor and the rectifier 22 is connected to the conductor, and then, the transformer 18 is connected to the cable 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of testing a DC power cable for energization.

[0002]

2. Description of the Related Art In FIG. 5, 10 is a test transformer and 1 is a test transformer.
2 is a voltage doubler rectifier circuit, and 14 is a sample of a DC power cable. A DC voltage for testing is applied to the sample 14 by the voltage doubler rectifier circuit 12. Both ends of the sample 14 are short-circuited by the conductor 16 to form a closed circuit, and a test AC current is passed through the current transformer 18.

[0003]

In the conventional energization test of the DC power cable, as described above, the energization was DC, but energization was AC, and especially DC energization was not performed. However, in the case of AC energization, there is a possibility that the evaluation result may be different from that of the actual line because it is not affected by the space charge, which is a problem in the case of DC.

[0004]

[Means for Solving the Problems]

(1) As shown in FIGS. 1, 2 and 3, a cable sample 1
An auxiliary cable 20 different from that of No. 4 is prepared, and an alternating current is made to flow through the current transformer 18, and the alternating current is converted to a direct current and is made to flow to the cable sample 14. (2) Alternatively, as shown in FIG. 4, without using the auxiliary cable 20, both ends of the cable sample 14 are short-circuited by the conductor 23 to form a closed circuit, and the conductor 23 is provided with the half-wave rectifier 22 insulated from the ground. . Then, the current transformer 18 is attached at an arbitrary position in the closed circuit so that the DC current generated by the action of the current transformer 18 and the rectifier 22 is passed through the cable sample 14.

[0005]

[Operation] Both DC and energization are performed with DC. Therefore, the same evaluation as the actual line becomes possible.

[0006]

First Embodiment FIG. 1 is an explanatory diagram of a first embodiment of the present invention, and FIG. 2 is a circuit diagram. In this case, as described above, the auxiliary cable 20 is used in addition to the sample 14. In this auxiliary cable 20, a current (effective value) of the same degree as that of the sample 14 flows, and a voltage of the same degree (added via a rectifier described later) is applied.
It has to withstand it. Any DC or AC power cable may be used as long as it can withstand it.
If one auxiliary cable 20 is prepared, it can be used repeatedly. Both the sample cable 14 and the auxiliary cable 20 are hung by the insulator 36 so as not to fall.

Both ends of the auxiliary cable 20 are short-circuited by a conductor 21, and a full-wave rectifier 22 is provided in the middle of the conductor 21. Alternating current is passed through the auxiliary cable 20 through the power transformer 18, converted into direct current by the rectifier 22, and then passed through the sample 14.

Reference numeral 24 shows the entire DC current measuring device. For this, a telemetry method including a sending unit 26, a transmitting unit 30, and a receiving unit 32 is used. The delivery unit 26 is, for example, the flow divider 2
7 and a converter 28, which is composed of a current detection element, an A / D conversion element, an E / O conversion element, and the like.
The power source of the converter 28 is, for example, a flow charging system of a solar cell and a battery.

The feeding unit 26 (including the battery of the converter 28) and the rectifier 22 are housed in one case 34 and suspended by an insulator 36 to be insulated from the ground.

The receiving portion 32 is installed on the ground. Receiving unit 32
Is composed of, for example, an O / E conversion element / D / A conversion element / display. For the transmission unit 30 between the sending unit 26 in the case 34 and the receiving unit 32 on the ground, for example, an electrically insulating optical fiber is used.

Since a large current flows through the rectifier 22 and the temperature becomes considerably high, it is cooled by the blower 38. The blower 38 is installed on the ground. An insulating hose 40 is connected to this, and its outlet is cooled toward the rectifier 22. As the insulating hose 40, one that can withstand the test voltage is used. The voltage doubler rectifier circuit 12, the sample 14, and the auxiliary cable 20 are also hung by the insulator 36 and separated from the ground.

[0012]

[Embodiment 2] FIG. 3 shows a case where single-phase half-wave rectification is performed. Although the DC current value with respect to the AC current value is smaller than that in full-wave rectification, the AC current value may be increased accordingly.

[0013]

Third Embodiment FIG. 4 shows a case where the auxiliary cable 20 is not used. In this case also, half-wave rectification is performed. That is, both ends of the cable sample 14 are short-circuited by the conductor 23 to form a closed circuit, and the conductor 23 is provided with the half-wave rectifier 22 insulated from the ground. The current transformer 18 is attached to the cable sample 14. Then, the direct current generated by the action of the current transformer 18 and the rectifier 22 is caused to flow through the cable sample 14. It should be noted that, as shown in FIG. 4, it is not necessary to use an auxiliary cable as compared with the cases of FIGS.

[0014]

[Effects of the Invention] Both the charging and the energization are performed by direct current. Therefore, the same evaluation as the actual line becomes possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is a circuit diagram of the embodiment shown in FIG.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of Embodiment 3 of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 10 Test Transformer 12 Double Voltage Rectifier Circuit 14 Sample of DC Power Cable 16, 21 Conductor 18 Current Transformer 20 Auxiliary Cable 21, 23 Conductor 22 Rectifier 24 DC Current Measuring Device 26 Shunting Section 27 Shunt 28 28 Converter 30 Transmission part 32 Received part 34 Case 36 Insulator 38 Prowa 40 Insulation hose

Claims (2)

[Claims] 1. In an energization test in which a current is applied to a DC power cable sample under the application of a DC high voltage, an AC current is applied to a cable different from the cable sample via a current transformer, and the AC current is applied. A method for conducting an energization test of a DC power cable, in which a rectifier insulated from the ground is used to convert the DC current into a DC current, which is then passed through the cable sample. 2. In an energization test in which an electric current is applied to a DC power cable sample under the application of a DC high voltage, both ends of the cable sample are short-circuited with a conductor to form a closed circuit, and the conductor is insulated from the ground. A single-phase half-wave rectifier is provided, a current transformer is attached to the closed circuit, and a DC current generated by the action of the current transformer and a rectifier is passed through the cable sample. Test method.