KR102028762B1 - Apparatus for accelerated degradation testing of cable - Google Patents

Abstract

The present invention is an acceleration degradation test apparatus of a cable consisting of a tank for storing deionized water, a cable immersed in the deionized water, a deionized water manufacturing unit for producing the deionized water, and a monitoring system for measuring the leakage current of the cable, Apparatus for accelerated degradation test of cables using deionized water containing low metallic ions and impurities. Technology for improving the reliability of life test and accurately evaluating cable insulation performance using signal phase difference. to be.

Description

Accelerated deterioration test apparatus of cable {APPARATUS FOR ACCELERATED DEGRADATION TESTING OF CABLE}

The present invention is an apparatus for accelerated degradation test of a cable, specifically, an apparatus for performing accelerated degradation test of a cable using deionized water having a low content of metallic ions and impurities, which improves reliability of a life test and improves phase difference of a signal. The present invention relates to an apparatus for accurately evaluating the insulation performance of cables.

Power cables can be classified into general cables (CV, CE), flame retardant cables (FR-CV, FR-PH), and halogen-free flame retardant cables (HFCO). In particular, the cable used for high voltage power is made of insulating material, and it is largely classified into XLPE (Cross Linked Polyethylene) and EPR (Ethylene Propylene Rubber).

In the case of XLPE cable, the polymer plastic insulation material has the advantages of high heat curing temperature, low heat deformation, high heat resistance, water resistance and chemical resistance, strong stress cracking resistance and light weight. Therefore, it is used from 3.3kV high voltage power system to 22.9kV special high voltage power system and is used for transmission line.

However, there is a lack of a test apparatus capable of measuring long-term life for such plastic insulated power cable, and its reliability is also low. In particular, in an environment in which a large amount of moisture is present, there is a problem in that the life is abruptly shortened and the life is shortened, and the equipment to measure it also has low reliability.

In order to solve this problem, there is a power cable immersion and conduction test apparatus of Korea Patent Publication No. 2005-0029599 that accelerates degradation by immersing the cable in the tank. However, there was a limitation in that it caused errors in the life test results due to impurities present in the water.

Therefore, the necessity of the technology regarding the test apparatus which can test the accelerated degradation test of a more accurate cable emerged.

An object of the present invention is to improve the reliability of the life test by performing the accelerated degradation test of the cable using deionized water containing low metallic ions and impurities, and to accurately evaluate the insulation performance of the cable using the phase difference of the signal. An accelerated degradation test apparatus is provided.

Accelerated deterioration test apparatus of the present invention to solve the above problems, the tank containing a cable immersed in a fluid; And a monitoring system connected to the cable to measure a leakage current, wherein the fluid contained in the tank is deionized water, and further includes a deionized water producing unit connected to the water tank, wherein the deionized water producing unit is formed of metallic ions or An auxiliary water tank which deionizes an impurity content to a predetermined value or less and is connected to an auxiliary water supply pipe to the deionized water production unit; A water level measuring unit for measuring the level of the deionized water stored in the water tank; And a control unit for receiving a water level measurement value from the water level measurement unit and controlling a valve installed in the auxiliary water supply pipe, wherein the control unit opens and closes the valve according to the water level measurement value.

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At this time, the control unit may be operated to open the valve to supply fluid to the deionized water from the auxiliary water tank when the level measurement value is less than the predetermined value.

At this time, the electrical conductivity measuring unit for measuring the electrical conductivity of the fluid discharged from the water tank, and receives a conductivity measurement value from the electrical conductivity measuring unit, and includes a control unit for controlling the operation of the deionized water production unit, the control unit includes a conductivity measurement value Can be operated according to the deionized water production unit.

At this time, a circulation pump for flowing the fluid discharged from the water tank to the control unit may be installed in the pipe discharged from the water tank.

At this time, the monitoring system is amplified in the leakage current measuring unit for measuring the leakage current generated from the cable, the noise filter unit for removing the noise of the leakage current, the signal amplifier for amplifying the leakage current from which the noise is removed and the signal amplification unit It may include a deterioration state output unit for outputting a leakage current.

At this time, the monitoring system may further include a comparison determination unit for comparing the phase difference and amplitude difference of the leakage current amplified by the signal amplifier with a predetermined phase difference value and amplitude difference value, and transmits the comparison result to the deterioration state output unit. have.

At this time, the cable fixing portion for holding both ends of the cable further includes, the cable fixing portion is an open ring of one point, the material may be composed of different inner skin and outer shell.

At this time, the inner shell is composed of EPDM (Etylene Preopylene Terpolymers) material, the outer shell may be composed of ABS resin (Acrylonitrile-Butadiene-Styrene copolymer) material.

At this time, the cable fixing part is formed on the fasteners formed at one end of the outer shell, the fasteners connected to the elastic member to the fasteners, the engaging protrusions formed at the other end of the outer shell and the fasteners, and tightening levers to apply tension to the elastic members by rotational operation. It can be configured as.

According to the accelerated degradation test apparatus of the cable of the present invention, deionized water from which metallic ions and impurities are removed is used to greatly improve the reliability of the accelerated life test as well as the accelerated tree test.

In addition, the present invention allows the use of deionized water to measure actual deterioration conditions that could not be performed when using tap water or other unpurified water.

In addition, the present invention is equipped with a separate device for producing and supplying deionized water, and equipped with a monitoring device for measuring the conductivity in real time, by maintaining the deionized water used for the test to contain impurities below the appropriate level Can maintain high reliability.

In addition, the present invention increases the length of the submerged tank, reduces the height to minimize the effect between the cables to be tested to improve the reliability of the tree tree test.

1 is a structural diagram showing an accelerated degradation test apparatus of the cable of the present invention.
2 is a structural diagram showing an acceleration deterioration test apparatus of a cable provided with a monitoring system in the practice of the present invention.
3 is a block diagram of an internal configuration constituting the monitoring system.
4 is an actual use state diagram of the deterioration state output unit of the monitoring system.
Figure 5 is a comparison of the tank of the conventional cable test apparatus and the tank of the cable test apparatus of the present invention.
Figure 6 is a comparison of the cable fixing part of the conventional cable test apparatus and the cable fixing part of the cable test apparatus of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Here, the repeated description, well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention, and detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more completely describe the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a structural diagram showing an accelerated degradation test apparatus of the cable of the present invention.

Referring to Figure 1, the accelerated deterioration test apparatus of the cable of the present invention comprises a water tank 100, deionized water production unit 200, electrical conductivity measurement unit 210, control unit 220, circulation pump 300 It is.

At this time, the water tank 100 is further connected to the auxiliary water tank 130 for storing water to supply deionized water from the outside. In addition, the water level measuring unit 230 for measuring the water level inside the water tank 100 is installed.

The auxiliary water tank 130 is connected to the deionized water production unit 200 and is connected to the control unit 220. A pipe connected between the deionized water production unit 200 and the auxiliary water tank 130 and flowing water is called an auxiliary water supply pipe 140.

One side of the auxiliary water supply pipe 140 is formed with a second valve 222 that can open and close the pipe. The second valve 222 is opened and closed by the controller 220.

The water tank 100 is connected to the deionized water production unit 200 and the deionized water supply pipe 110 through which deionized water can flow. At one point of the deionized water supply pipe 110, a first valve 221 that opens and closes the pipe is formed. The first valve 221 is opened and closed by the controller 220.

Deionized water production unit 200 is connected to the water tank 100, the auxiliary water tank 110 and the control unit 220 by a pipe. The deionized water production unit 200 serves to deionize the water introduced from the auxiliary water tank 110 and the control unit 220 and supply the deionized water to the water tank 100.

Since the deionization process is a well-known technique, a detailed description thereof will be omitted, and the present invention is characterized by performing an accelerated test by supplying deionized water to the water tank 100 in which the cable test is performed.

The controller 220 is connected to the water tank 100 and the deionization manufacturing unit 200 by a pipe through which water can flow. In particular, between the control unit 220 and the water tank 100 is connected to the deionized water discharge pipe 120 through which water can flow.

At one point of the deionized water discharge pipe 120, an electrical conductivity measurement unit 210 for measuring the electrical conductivity of the deionized water discharged from the water tank 100 is installed.

In addition, at one point of the deionized water discharge pipe 120, a circulation pump 300 for flowing deionized water discharged from the water tank 100 to the controller 220 is installed.

The electrical conductivity measuring unit 210 performs a cable deterioration test in the water tank 100, measures the electrical conductivity of the discharged deionized water, and transmits the measurement result to the controller 220.

Since the deionized water is exposed to the outside air while the test is performed in the water tank 100, impurities may be introduced from the outside, and the electrical conductivity may be increased, which may cause errors in the test. To prevent this, the electrical conductivity measuring unit 210 is installed in the deionized water discharge pipe 120 to determine the current water state in real time.

If the measurement result exceeds the reference value, the control unit 220 operates the deionized water production unit 210 to remove impurities therein such that the water becomes below the reference value. At this time, the reference value is preferably 0.1 µS / cm.

Due to this structure, the water supplied to the water tank 100 can always supply deionized water having an electrical conductivity of less than or equal to a reference value. In other words, the water in the water tank 100 is deionized water which is lowered to the reference value by removing impurities and metallic ions. The water is minimized in the accelerated deterioration test to minimize errors and improve the reliability of the test results.

The water level measuring unit 230 is installed inside the water tank 100 to measure the surface height of the deionized water in the water tank 100 in real time. When the deterioration characteristic test of the cable is performed, deionized water in the water tank 100 is evaporated due to the heating of the cable. Therefore, the water level measuring unit 230 measures the height of the water surface in real time and transmits the result to the control unit 220. The controller 220 opens the first valve 221 and the second valve 222 when the surface of the deionized water is significantly lower than the preset value, and supplies the deionized water into the water tank 100.

At this time, the preset value is preferably set to a very small number so that the deionized water surface in the water tank 100 does not change.

The second valve 222 is opened to flow the water stored in the auxiliary water tank 130 to the deionized water production unit 200. The deionized water production unit 200 deionized the introduced water and supplies deionized water to the water tank 100.

When the water level of the water tank 100 again reaches a predetermined value, the controller 220 closes the first valve 221 and the second valve 222 to block the supply of deionized water introduced into the water tank 100.

In this way, the water level in the water tank 100 is always kept constant, and by circulating the deionized water through the valve opening and closing operation of the circulation pump 300 and the control unit 220, the water temperature can be kept constant, thereby testing The reliability of the test results was improved by maintaining a constant environment around the cable.

2 is a structural diagram showing an acceleration deterioration test apparatus of a cable provided with a monitoring system in the practice of the present invention.

Referring to FIG. 2, the neutral wire 30 is wound around the cable 10, and the deterioration characteristic is tested by immersion in the water tank 100.

The cable 10 is composed of a conductor 11, an insulator 12 surrounding the conductor, and a sheath 13 surrounding the insulator, and the neutral wire 30 is wound around the sheath 13. The neutral wire 30 is grounded with the ground to make the potential zero, and an alternating current is applied to the conductor 11 to generate a potential difference between the conductor 11 and the neutral wire 30.

At this time, a current flows through the insulator 12 formed between the conductor 11 and the sheath 13, and the degradation current of the cable can be tested by measuring the leakage current separately.

Existing test equipment uses unpurified water, such as deionized water, so that leakage current flows into water under the influence of impurities and metallic ions, making it impossible to measure leakage current of cables. Therefore, there was a limit to perform indirectly by installing only a remote monitoring device that records the amount of change in voltage and current applied to the power cable.

However, the present invention is a test apparatus using deionized water, and since the leakage current does not flow into the highly insulating deionized water, it is possible to measure the leakage current of the cable.

The stress cone 14 is provided at the point where the sheath 13 of the cable 10 peels off, and the neutral wire 30 is connected. Neutral wire 30 is wound around the cable 10, it is wound tightly to perform an experiment winding appropriately so as not to affect the neutral wire.

Neutral wire 30 is grounded and connected to the monitoring system 400 at the same time. Monitoring system 400 is a device for measuring the current degradation of the cable by measuring the leakage current of the cable (10).

The existing test apparatus enables the leakage current measurement which could not be performed by using water other than deionized water, and the present invention enables the test by using deionized water, and also the result derived from the existing test apparatus by measuring and analyzing directly. Better test results can be obtained.

3 is a block diagram of an internal configuration constituting the monitoring system, Figure 4 is a diagram showing the actual use state of the degradation state output unit of the monitoring system.

Referring to FIG. 3, the monitoring system 400 includes a leakage current measuring unit 410, a noise filter 420, a signal amplifier 430, and a degraded state output unit 440.

The leakage current measuring unit 410 is a device for measuring a current leaking due to a defect generated during the degradation test of the cable 10 submerged in the water tank 100. Since the deionized water does not contain impurities or metallic ions, when the leakage current is generated in the cable, the deionized water flows along the neutral wire 30. The leakage current measurement unit 410 detects this, and transmits the information of the detected leakage current to the noise filter unit 420.

The noise filter 420 removes the noise of the leakage current and transmits the signal to the signal amplifier 430 to facilitate the classification of the filtered leakage current.

The signal amplifier 430 amplifies the received leakage current information and transmits it to the deterioration state output unit 440.

As shown in FIG. 6, the deteriorated state output unit 440 may be a display, and represents a phase difference or amplitude difference of the amplified corresponding leakage current. Thus, the experimenter can determine whether the leakage current is generated, and if so, by the difference in phase or amplitude.

In addition, the comparison determination unit 450 may be further installed in the monitoring system 400. In the comparison determination unit 450, the experimenter presets a phase difference value or an amplitude difference value, receives leakage current information from the signal amplifier 430, and compares the preset phase difference value and the amplitude difference value. Accordingly, when the phase difference value and the amplitude difference value are greater than or equal to, the corresponding information is transmitted to the deterioration state output unit 440 so that the experimenter can easily determine whether leakage current is generated.

Figure 5 is a comparison of the tank of the conventional cable test apparatus and the tank of the cable test apparatus of the present invention.

Referring to FIG. 5, the tank of the conventional cable test apparatus had to perform an audit tree test in a circular shape of the cable. This is because the water tank is manufactured with a width of 2.0m, a length of 4.5m, and a height of 1.5m. In this case, the reliability of the tree test results is not only low due to the influence of the cables wound in a circle, but also for the cables of 325 mm2 or more. As even winding was difficult, the life test was limited.

The water tank 100 of the cable test apparatus of the present invention is manufactured by a width of 2.0m, a length of 5.0m, and a height of 0.8m, it can be carried out without the need to wind the cable. That is, 0.5m longer than the conventional water tank, 0.7m in height is reduced, and the amount of water required for the immersion of the cable can be carried out by reducing the amount of water by 60% than conventional.

Figure 6 is a comparison of the cable fixing part of the conventional cable test apparatus and the cable fixing part of the cable test apparatus of the present invention.

A cable anchor is a device for fixing both ends of a cable submerged in a tank.

Referring to Figure 6, the cable failure of the conventional cable test apparatus is a structure for fixing the cable by combining two semi-circular brackets around the cable. In the conventional cable fixing, a metal material such as iron was generally used, and to prevent damage to the surface of the cable, an additional jacket was fixed between the bracket and the cable.

On the contrary, the cable fixing part 500 of the cable test apparatus of the present invention is composed of the inner shell 510 formed in the C-type and the outer shell 520 surrounding it. At this time, the endothelium 510 is composed of EPDM (Etylene Preopylene Terpolymers) having excellent elasticity and high heat resistance. In addition, the outer shell 520 is composed of ABS resin (Acrylonitrile-Butadiene-Styrene copolymer). As such, the inner shell 510 and the outer shell 520 are made of a stretchable material, and can be held and fixed without damaging the sheath 13 of the cable.

A fastener 530 is coupled to one end of the outer shell 520, and the fastener 530 is connected through the latch 540 and the elastic member 550. At this time, the elastic member 550 may be typically composed of a rubber or a spring.

A locking protrusion 560 is formed at the other end of the outer shell 520 to protrude toward the outer circumferential surface of the outer shell 520 so that the latch 540 can be caught.

The fastener 530 is provided with a tightening lever 570, and a user may apply tension to the elastic member 550 by operating the tightening lever 570.

As such, the cable fixing part 500 may be formed in a C type to fix cables of various sizes, and tightly constrained to fix the cable by using the clamp 540 and the fastening lever 570 of the fastener 530. The soft materials of the endothelium 510 and the outer shell 520 can be used to perform tests without damaging the cable.

As described above, the ribbon for scavenging the self-extinguishing pipe combined with the reinforcing member according to the present invention is not limited to the configuration and method of the embodiments described as described above, but the embodiments may be variously modified. All or part of each of the embodiments may be configured to be selectively combined so that.

10: Cable 100: Countertop
130: auxiliary water tank 200: deionized water manufacturing unit
210: electrical conductivity measurement unit 220: control unit
230: water level measurement unit 300: circulation pump
400: monitoring system 500: cable fixing

Claims (11)

A water tank containing a cable submerged in the fluid;
A monitoring system connected to the cable for measuring leakage current;
The fluid contained in the tank is deionized water,
Further comprising a deionized water production unit connected to the water tank,
The deionized water production unit deionized the metallic ion or impurity content of the fluid to a predetermined value or less,
An auxiliary water tank connected to an auxiliary water supply pipe to the deionized water production unit;
A water level measuring unit for measuring the level of the deionized water stored in the water tank; And
A control unit for receiving a level measurement value from the level measuring unit and controlling a valve installed in the auxiliary water supply pipe;
And the control unit opens and closes the valve according to the level measurement value. delete delete The method according to claim 1,
And the control unit opens the valve to supply the fluid from the auxiliary water tank to the deionized water when the level measurement value is less than or equal to a predetermined value. The method according to claim 1,
An electrical conductivity measurement unit for measuring electrical conductivity of the fluid discharged from the tank;
Receiving a conductivity measurement value from the electrical conductivity measuring unit, including a control unit for controlling the operation of the deionized water production unit,
The control unit is an acceleration degradation test apparatus of the cable, characterized in that for controlling the operation of the deionized water production unit in accordance with the measured conductivity. The method according to claim 1,
It is installed in the pipe discharged from the water tank, the accelerated deterioration test apparatus for a cable, characterized in that it further comprises a circulation pump for flowing the discharged fluid to the controller. The method according to claim 1,
The monitoring system,
Leakage current measuring unit for measuring the leakage current generated from the cable;
A noise filter unit for removing noise of the leakage current;
A signal amplifier for amplifying the leakage current from which the noise is removed; And
And a deterioration state output unit configured to output the leakage current amplified by the signal amplifier. The method according to claim 7,
The monitoring system further includes a comparison determination unit for comparing the phase difference and amplitude difference of the leakage current amplified by the signal amplifier with a predetermined phase difference value and an amplitude difference value, and transmitting a comparison result to the deterioration state output unit. Accelerated deterioration test apparatus for the cable, characterized in that. The method according to claim 1,
Further comprising a cable fixing for holding both ends of the cable,
The cable fixing part is an annular open ring of one point, accelerated degradation testing device of the cable, characterized in that the material is composed of a different inner and outer shell. The method according to claim 9,
The inner shell is composed of EPDM (Etylene Preopylene Terpolymers) material, the outer shell is accelerated degradation test apparatus, characterized in that the ABS resin (Acrylonitrile-Butadiene-Styrene copolymer) material. The method according to claim 9,
The cable fixing part,
A fastener formed at one end of the shell;
A latch connected to the fastener with an elastic member;
A locking protrusion formed at the other end of the shell; And
Accelerated deterioration test apparatus of the cable further comprises a tightening lever formed in the fastener to apply a tensile force to the elastic member by a rotation operation.

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