KR20170030426A - Termination connection box, and system and method for observing water in the same - Google Patents

Abstract

The present invention provides a terminal connection box, a moisture monitoring system of the terminal connection box, and a moisture monitoring method of the terminal connection box which can prevent a moisture inflow while filling insulating oil in the terminal connection box, and furthermore can prevent damage to or a failure of the terminal connection box by checking a moisture amount or a humidity amount inside the terminal connection box when driving the terminal connection box.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end connection structure, a moisture monitoring system of a termination junction box, and a moisture monitoring method of a termination junction box,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a termination structure, a moisture monitoring system of a termination box, and a moisture monitoring method of a termination box.

Generally, a power cable is used to power a desired location through the ground, ground, or seabed using a power-supplying conductor. For such a power cable, it is very important to insulate the conductor. For this purpose, the insulating layer for insulating the conductor is made of XLPE (Cross-linked Polyethylene) or the like, I am using it.

The power cables are connected by a joint box at intervals of several hundred meters or tens of kilometers, and the ends of the power cables are connected to the wires by a termination connection box. The termination junction box can be classified into a termination termination box, a gas termination box and an oil termination box depending on the connected state of the conductor ends of the cables.

The end connection box includes an auxiliary pipe into which the power cable is inserted for a predetermined length, and the inside of the auxiliary pipe is filled with insulating oil. In this case, moisture may be introduced into the interior of the pipe during filling of the insulating oil, and in particular, when water flows into the interior of the pipe during operation of the terminal connection box, water drops may be dropped to lower the dielectric strength of the terminal- Which may cause breakage or failure of the termination enclosure.

The object of the present invention is to prevent the inflow of water during the filling of the end connection box with the insulating oil and to check the amount of moisture or humidity in the termination connection box at the time of operation of the termination connection box, A moisture monitoring system for the end connection box, and a moisture monitoring method for the end connection box.

An end connection structure according to an embodiment of the present invention includes: a termination connection box in which one end of a power cable is inserted and an insulation oil is filled; And a sensor positioned within the termination box and sensing a moisture content of the insulating oil; .

In the present invention, the power cable may include a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer positioned outside the insulation layer, wherein the termination junction box includes: an inner tube into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; And an electric field relieving cone that relaxes the electric field inside the pipe; Wherein the electric field relieving cone is electrically connected to the outer semiconductive layer; And an insulator surrounding the semiconducting element, and the sensor may be inserted into the termination enclosure through the lower metal fitting.

In the present invention, the sensor is disposed between the lower bracket and the triple point, and the triple point is a point at which the insulation layer of the power cable, the insulation portion of the electric field relieving cone, and the half- .

In the present invention, a distance between the lower metal fitting and the upper end of the sensor may be less than a distance between the lower metal fitting and the triple point.

According to the present invention, the external surface electric field of the pipe and the electric field at one end of the sensor vary according to the position of the sensor inserted into the terminal box, and when the external surface electric field exceeds the predetermined electric field value The sensor may be disposed in the termination box such that no discharge occurs on the outer surface of the tank and that an electric field at one end of the sensor exceeds a predetermined electric field value so that discharge does not occur in the insulating oil.

In the present invention, the sensor may be disposed in the termination junction box such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm.

In the present invention, the sensor can calculate the moisture content by sensing temperature and relative humidity.

The moisture monitoring system of the end connection box according to an embodiment of the present invention is a system for monitoring the moisture of the end connection box into which one end of the power cable is inserted, wherein the moisture monitoring system includes a sensing unit for sensing the moisture amount of the insulation oil in the termination connection box .

In the present invention, the controller may include a controller for determining the amount of moisture or continuing the operation based on the information of the sensing unit.

In the present invention, the power cable may include a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer positioned outside the insulation layer, wherein the termination connection box includes: an inner pipe into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; An electric field relieving cone for relieving an electric field inside said pipe; Wherein the electric field relieving cone is electrically connected to the outer semiconductive layer of the power cable; And an insulating portion surrounding the half-conduction portion, wherein the sensing portion is positioned between the lower bracket and the triple point, and the triple point is connected to the insulating layer of the power cable, the insulating portion of the field- May be a point at which the entirety of the half-circle of the magnetic field contacts.

In the present invention, a distance between the lower metal fitting and the upper end of the sensing portion may be less than a distance between the lower metal fitting and the triple point.

According to the present invention, the external surface electric field of the pipe and the electric field at one end of the sensor vary according to the position of the sensor inserted into the terminal box, and when the external surface electric field exceeds the predetermined electric field value The sensor may be disposed in the termination box such that no discharge occurs on the outer surface of the tank and that an electric field at one end of the sensor exceeds a predetermined electric field value so that discharge does not occur in the insulating oil.

In the present invention, the sensor may be disposed in the termination junction box such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm.

In the present invention, the control unit may store data in the form of a look-up table as a change in relative humidity according to the temperature change of the insulating oil.

In the present invention, the control unit may calculate the temperature and the relative humidity of the insulating oil measured by the sensing unit and the moisture content of the insulating oil at the measured temperature from the look-up table.

In the present invention, the controller compares the calculated moisture amount with a predetermined first threshold value, compares the measured relative humidity with a predetermined first threshold value, and if the calculated moisture amount exceeds the predetermined first threshold value Or if the measured relative humidity is greater than or equal to the predetermined first threshold, a first alarm may be generated.

In the present invention, when the calculated moisture amount is less than the predetermined first threshold value or the measured relative humidity is less than the predetermined first threshold value, the control unit controls the temperature of the insulating oil measured by the sensing unit And the relative humidity and the moisture content of the insulating oil at the measured temperature from the look-up table.

In the present invention, the control unit recalculates the moisture content included in the insulating oil by the measured relative humidity and the temperature after generating the first alarm, compares the calculated moisture amount with a predetermined second threshold value, Comparing the measured relative humidity with a predetermined second threshold and generating a secondary alarm if the calculated moisture content is greater than or equal to the predetermined second threshold or the measured relative humidity is greater than or equal to the predetermined second threshold And the operation of the terminal connection box can be stopped.

In the present invention, when the calculated moisture amount is less than the predetermined second threshold value or the measured relative humidity is less than the predetermined second threshold value, the controller calculates the calculated moisture amount and the measured relative humidity respectively And when the calculated moisture amount is equal to or greater than the predetermined first threshold value or the measured relative humidity is equal to or greater than the predetermined first threshold value, .

In the present invention, the control unit may release the first alarm when the calculated moisture amount is less than the predetermined first threshold value or the measured relative humidity is less than the predetermined first threshold value.

In the present invention, the control unit may calculate the moisture content included in the insulating oil by the measured relative humidity and the temperature, and calculate the calculated moisture amount and the measured relative humidity, respectively, And comparing it with the threshold value can be repeated.

In the present invention, the sensing unit may calculate the moisture content by sensing temperature and relative humidity.

A moisture monitoring method for a terminal connection case according to an embodiment of the present invention is a method for monitoring a moisture content of a terminal connection case in which one end of a power cable is inserted and an insulating oil is filled, Sensing step; And a control step of calculating the moisture content or continuing the operation based on the information collected through the sensor; .

In the present invention, the power cable may include a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer positioned outside the insulation layer, wherein the termination connection box includes: an inner pipe into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; And an electric field relieving cone that relaxes the electric field inside the pipe; The electric field relieving cone being electrically connected to the outer semiconductive layer of the power cable; And an insulating portion surrounding the semi-conductive portion. In the sensing step, the insulating layer of the electric cable, the insulating portion of the electric field relieving cone, and the half circle of the electric field relieving cone It is possible to sense between the triple points, which are the tangent points.

In the present invention, the sensing may be performed at a distance less than a distance between the lower bracket and the triple point.

According to the present invention, the external surface electric field of the pipe and the electric field at one end of the sensor vary according to the position of the sensor inserted into the terminal box, and when the external surface electric field exceeds the predetermined electric field value The sensor may be disposed in the termination box such that no discharge occurs on the outer surface of the tank and that an electric field at one end of the sensor exceeds a predetermined electric field value so that discharge does not occur in the insulating oil.

In the present invention, the sensor may be disposed in the termination junction box such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm.

In the present invention, sensing the moisture content of the insulating oil in the sensing step may be calculated by measuring the temperature and relative humidity of the insulating oil.

According to one embodiment of the present invention, when the insulating oil is filled in the end connection case, the inside of the pipe is purged with nitrogen, and further the insulating oil is filled into the interior of the pipe in accordance with the relative humidity of nitrogen discharged from the pipe It is possible to prevent the inflow of moisture into the inside of the pipe when the insulating oil is filled.

According to the present invention, when moisture permeates from the outside due to damage to the end connection box due to vibration, thermal expansion and expansion during operation of the end connection box, the moisture amount or relative humidity of the insulating oil in the end connection box is checked, It is possible to monitor moisture infiltration during operation and prevent breakage or damage of the terminal connection box due to moisture infiltration.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing a termination box according to the present invention,
2 to 9 are diagrams showing an electric field distribution along the length of the end of the moisture sensor,
10 and 11 are flowcharts showing a control procedure for monitoring the moisture amount at the time of operation of the terminal connection box,
12 is a flowchart showing a control procedure for monitoring the amount of water at the time of filling the insulating oil in the terminal box.

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

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a termination box according to the present invention. FIG. 1, an internal structure is shown by cutting a part to show the internal structure of the termination box 400. [

Referring to FIG. 1, the termination receptacle 400 has an eyelet 410. The air pipe 410 has a predetermined space therein, and the power cable 100 is inserted into the electric cable 100 with a predetermined length as described later. The cap 410 serves to insulate and support the power cable. Thus, the apex 410 has a plurality of wrinkles or protrusions 412 along its surface in order to have sufficient electrical insulation strength. The insulation distance can be increased by the wrinkles or protrusions to improve the dielectric strength. The cap 410 may be made of rigid magnetic or polymeric resin so as to maintain an appropriate level of strength while having an insulating proof force.

The power cable 100 penetrates through the cap 410 and a conductor lead rod 11 electrically connected to the conductor 10 of the power cable 100 is protruded by a predetermined length through an upper end of the cap 410. The upper end of the aerator pipe 41 may have a cover 510 connected to the upper bracket 414. The conductor draw-out bar 11 penetrates through the cover part 510 and protrudes outside the aerator 410.

In the power cable 100, the components surrounding the conductor 10 are peeled off inside the cap 410 and only the conductor 10 is exposed and protruded at the end of the cap 410 to be connected to the work line (not shown). That is, in the case where the power cable 100 is inserted into the apron 410 of the termination connection box 400, the power cable 100 is removed from the outer semiconductive layer 16 and the insulating layer 14 is exposed As shown in Fig. In this case, the unremoved outer semiconductive layer 16 is inserted into the eyelet 410 by a predetermined length. That is, the power cable 100 is inserted into the apical tube 410 with the insulating layer 14 exposed, and the outer semiconductive layer 16 is inserted into the predetermined length apical 410.

Meanwhile, the insulating pipe 420 may be filled in the inner pipe 410. The insulating oil 420 flows between the power cable 100 and the inner wall of the aerator 410 inside the aerator 410 and functions to electrically isolate the oil. The method of filling the insulating oil will be described in detail later.

If the power cable 100 in which the outer semiconductive layer 16 is partially removed is exposed so that the insulating layer 14 is exposed to the outer semiconductive layer 16 when a voltage is applied between the inner semiconductive layer and the inner semiconductive layer, The electric field can be concentrated at the end of the electrode. This may cause breakage of the outer semiconductive layer 16 and the insulating layer 14. Therefore, as shown in the figure, the electric field relieving cone 460 for relieving the electric field concentration of the cable 100 may be provided in the interior of the air duct 410.

The electric field relieving cone 460 may include a semiconducting portion 462 connected to the outer semiconductive layer 16 of the cable 100 and an insulating portion 461 surrounding the semiconductive portion 462.

The insulation part 461 provided at the outer side of the electric field relieving cone 460 may be made of liquid silicone rubber (LSR), for example, and is provided at the outer side of the electric field relieving cone 460 to ensure insulation performance.

Semiconductor device 462 may be fabricated using semiconductive liquid silicone rubber (LSR) as an example. The semiconductive layer 462 is in contact with the outer semiconductive layer 16 of the cable 100, so that the electric field is not locally concentrated but spreads evenly.

The electric field relieving cone 460 may be electrically connected to the outer semiconductive layer 16 of the cable 100 inserted into the inner tube 410. That is, even when the cable 100 is inserted into the eyelet 410 with the insulating layer 14 of the cable 100 exposed, the outer semiconductive layer 16 is inserted into the eyelet 410 by a predetermined length . In this case, the semiconductive portion 462 of the electric field relieving cone 460 is electrically connected to the external semiconductive layer 16 inserted into the interior of the electron tube 410. Since the semiconductive layer 462 of the electric field relieving cone 460 is electrically connected to the external semiconductive layer 16 to prevent the electric field from concentrating on the end of the external semiconductive layer 16.

Hereinafter, when moisture permeates the inside of the termination junction box 400 during operation of the termination junction box 400, at least one of the relative humidity of the insulation oil and the amount of water contained in the insulation oil is detected, And a water monitoring system 800 for determining whether the operation of the end-connection box 400 is continued or not.

The moisture monitoring system 800 of the terminal box 400 includes a moisture sensor 600 positioned inside the aerator 410 and sensing the temperature and relative humidity of the insulating oil inside the aerator 410, A warning message is sent when at least one of the calculated moisture amount and the relative humidity is equal to or greater than a threshold value and a threshold value, And a controller 700 for determining whether the connection box 400 is continuously operated.

In the moisture sensor 600, since the upper portion of the termination box 400 relatively forms a high-pressure portion, it is difficult to mount a device including the moisture sensor on the upper portion of the interior of the aerator 410. When moisture permeates into the insulating oil 420 inside the aerator 410, the water drops down to the bottom of the aerator 410 due to the difference in specific gravity between the insulating oil and the insulating oil. Therefore, it is preferable that the moisture sensor 600 is disposed at a lower portion of the interior of the aerator 410.

For example, a lower bracket 470 through which the power cable 100 passes is provided at a lower portion of the end connection box 400, and the moisture sensing sensor 600 penetrates through the lower bracket 470 . In this case, the lower fitting 470 may be provided with an injection port (not shown) for injecting insulating oil into the interior of the aerator 410, and a sensor mounting hole And the moisture sensor 600 may penetrate the sensor mount 472 and be positioned inside the eye 410. [

In this case, the moisture sensor 600 may include a connection portion 620 connected to the sensor mounting hole 472 and a connection portion 620 extending from the connection portion 620 to the interior of the aerator 410, And a sensing unit 610 that senses the sensed signal. As an example, the sensing portion 610 may sense the relative humidity and temperature of the insulating oil 420. When the sensing unit 610 senses the relative humidity and temperature of the insulating oil 420, the moisture content of the insulating oil can be calculated through the sensed relative humidity and the temperature. As another example, the sensing unit may indirectly measure the moisture content of the insulating portion 420 directly or through various methods.

For example, the moisture monitoring system may store data in the form of a look-up table as a change in relative humidity with a change in temperature, and the moisture content of the insulating oil may be determined based on the temperature of the insulating oil measured by the sensing unit 610, The relative humidity, and the moisture content of the insulating oil at the measured temperature from the look-up table.

As described above, the moisture sensing sensor 600 is provided in the lower bracket 470 and it is possible to monitor the end connection box 400 during operation through the moisture monitoring system 800 as described later.

Generally, when water is generated in the inner pipe 410, the moisture is collected at the upper end of the electric field relieving cone 460 by the electric field, so that the sensing unit 610 is adjacent to the upper end of the electric field relieving cone 460 It is advantageous to measure relative humidity. The insulation layer 14 of the electric power cable 100, the insulation portion 461 of the electric field relieving cone 460 and the half circle of the electric field relieving cone 460 are formed at the upper end of the electric field relieving cone 460. [ There is a triple point T at which the contact point 462 contacts. When the sensing unit 610 is positioned adjacent to the triple point T, the electric field is concentrated on the sensing unit 610 and a discharge may occur at one end of the sensing unit 610, A discharge may be generated along the outer surface of the terminal connection box and damage or breakage of the terminal connection box may be caused.

More specifically, electrical appliances such as terminal boxes need not only withstand voltage at all times, but also with occasional lightning or insulation against abnormal voltages during opening and closing. However, it is economical to insulate against any abnormal voltage without breakage. Therefore, the voltage test voltage of the equipment is standardized by "Test Voltage Standard" for electric appliances higher than high voltage. In this standard, the AC test voltage open / close impulse test voltage and the lightning impulse voltage are shown for each use voltage, but the value of the brain impulse test voltage is called BIL (Basic Impuls Insulation Level).

An insulation design is made to withstand the value of the brain impulse test voltage even in the case of a terminal connection box connected to a cable through which high-voltage power is transmitted. For example, for a 500kV class cable, the BIL according to the International Electronical Committee (IEC) standard is 1550kV, and the value of the brain impulse test voltage applying the temperature coefficient, the deterioration coefficient, and the design margin is approximately 1900kV. When a test impulse voltage value of 1900 kV is applied, the external surface field of the pipe shall not exceed 2.5 kV. If the external surface electric field exceeds 2.5kV, discharge may occur along the outer surface of the pipe and the end connection box may be damaged. Therefore, the aisle of the termination box must satisfy the predetermined impulse design criterion at the predetermined brain impulse test voltage value.

When the sensor 610 is inserted into the terminal box 400 and the terminal 610 is inserted into the terminal box 400 according to the position of the sensor 610 in the terminal box 400, So that the electric field at the surface is changed. Therefore, when the external surface electric field of the eye 420 exceeds a predetermined electric field value, no discharge occurs on the outer surface of the eye 420, and when the electric field at one end of the sensor 610 exceeds a predetermined electric field value Preferably, the sensor 610 is disposed within the termination junction so that no discharge occurs in the insulating oil 420. As an example, the sensor 610 may be configured such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor 610 does not exceed 20 kV / mm .

The distance from the lower metal fitting 470 of the aerator 410 to the upper end of the sensing portion 610 of the moisture sensing sensor 600 when determining the position of the sensing portion 610 of the moisture sensing sensor 600 L ₂ may be set to be smaller than the distance L ₁ from the lower metal fitting 470 of the pipe 410 to the triple point of the field relief cone 460.

For example, the distance from the lower bracket (470) to the triple point of the field-relief cones 460 in the distance (L ₂₎ is the lower bracket 470 of the upper end portion to the sensing unit (610) (L ₁₎ Or less.

In this case, the external surface electric field of the cap 410 does not exceed 2.5 kV / mm, and the electric field at one end of the sensor 610 does not exceed 20 kV / mm.

FIGS. 2 to 9 are diagrams showing the distribution of the equipotential lines in the eye 410 according to the position of the upper end of the sensing unit 610. FIG.

2 is a view showing a state in which the distance L ₂ from the lower bracket 470 to the upper end of the sensing unit 610 is smaller than the distance L ₁ from the lower bracket 470 to the triple point of the field relief cone 460 For example, about 50%. 3 is an enlarged view of the area "A" in Fig.

Referring to FIGS. 2 and 3, it can be seen that the distance between the equipotential lines is very wide at the upper end of the sensing unit 610, so that the electric field is small.

4 shows the distance L ₂ from the lower bracket 470 to the upper end of the sensing portion 610 to the distance from the lower bracket 470 to the triple point T of the field relief cone 460 (L ₁ ). 5 is an enlarged view of the area "B" in Fig. 6 is a graph showing the external surface electric field of the eye 420 in the section V1-V2 shown in FIG. 4 when 1900 kV is applied to the cable 100. FIG.

4 and 5, in the case of FIGS. 4 and 5, as in the case of FIGS. 2 and 3, it can be seen that the interval of the equipotential lines is relatively wide at the upper end of the sensing unit 610, have.

6 shows a case where the height of the sensing unit 610 is 1195 mm and the upper end of the sensing unit 610 is disposed at the same height as the triple point T. When the cable impulse test voltage value of 1900 kV is applied to the cable 100 Is a graph showing the surface electric field at the outside of the pipe. Referring to FIG. 6, it can be seen that the external surface field of the outer pipe at the point 3.527 * 10 ³ mm away from the top of the pipe in the direction from the top of the pipe to the bottom of the pipe is the highest at 2.4 kV / mm. As described above, since the impulse design criterion of the external surface electric field of the external pipe in the case where the brain impulse test voltage value is 1900 kV is 2.5 kV / mm, the distance L ₂ from the lower metal fitting 470 to the upper end of the sensing portion 610 ) Is substantially equal to the distance (L ₁ ) from the lower metal fitting (470) to the triple point (T) of the field relieving cone (460), the impulse design reference is not exceeded, I never do that.

On the other hand, Figure 7 is the distance (L _2), the distance (L ₁ in the lower bracket (470) to the triple point of the field-relief cones 460 of the upper end portion to the sensing unit 610 in the lower bracket 470, , For example, 35 mm higher than the triple point T, 8 is an enlarged view of the "C" area in Fig. 9 is a graph showing the external surface electric field of the pipe 420 between the sections V1 and V2 shown in FIG. 7 when 1900 kV is applied to the cable 100. FIG.

Referring to FIGS. 7 and 8, it can be seen that the distance between the equipotential lines at the upper end of the sensing unit 610 is relatively narrow as compared with the case of FIGS. 3 and 5, and the electric field is relatively increased.

9 shows a case where the height of the sensing unit 610 is 1230 mm and the upper end of the sensing unit 610 is positioned 35 mm higher than the triple point T and the cable 100 is applied with a brain impulse test voltage value of 1900 kV, Fig. 5 is a graph showing the external surface field intensity. Fig. Referring to FIG. 6, it can be seen that the external surface field of the outer pipe at the point 3.528 * 10 ³ mm away from the upper part of the pipe in the direction from the upper part of the pipe to the lower part of the pipe is the highest at 2.53 kV / mm.

As described above, since the impulse design criterion of the external surface electric field of the external pipe in the case where the brain impulse test voltage value is 1900 kV is 2.5 kV / mm, the distance L ₂ from the lower metal fitting 470 to the upper end of the sensing portion 610 Is greater than the distance (L ₁ ) from the lower bracket 470 to the triple point T of the field relief cone 460, the impulse design criterion is exceeded and the damage and breakage There is a concern.

Hereinafter, a method of monitoring the water amount during operation of the end connection box 400 by the moisture monitoring system 800 having the above-described configuration will be described.

Figs. 10 and 11 are flowcharts showing a control procedure for monitoring the amount of water at the time of operation of the terminal box. Fig.

Referring to FIGS. 10 and 11, the relative humidity and the temperature of the insulating oil 420 in the interior of the pipe 410 are measured by the moisture monitoring system 800 (S210).

Next, the controller 700 calculates the amount of water contained in the insulating oil according to the measured relative humidity and temperature (S220).

For example, information about the humidity change due to the temperature change is constructed in the database while changing the temperature with the insulating oil having a certain moisture content already known. The experiment is performed while varying the moisture content to construct a database, and the database is stored in the controller 700. Accordingly, when the temperature and relative humidity of the insulating oil 420 are known by the moisture sensor 600, the controller 700 can calculate the amount of water contained in the insulating oil through the database.

Next, the calculated moisture amount and the measured relative humidity are compared with a predetermined first threshold value and a predetermined first threshold value, respectively (S230). Here, the first threshold value and the first threshold value may be appropriately determined according to the type of the insulating oil. For example, when the insulating oil is polybutene, the first threshold may be determined to be approximately 20 ppm.

At this time, when the calculated moisture amount is equal to or greater than a predetermined first threshold value or the measured relative humidity is equal to or greater than a predetermined first threshold value, the controller generates a first alarm (S240). On the other hand, when the calculated moisture amount is less than the predetermined first threshold value and the measured relative humidity is less than the predetermined first threshold value, the controller 700 determines the moisture amount included in the insulating oil by the measured relative humidity and temperature (S220). ≪ / RTI >

In this case, when the temperature of the insulating oil 420 is increased due to the operation of the terminal box 400, the saturated moisture content of the insulating oil is increased, and the relative humidity is low. Since the relative humidity varies with temperature, it is difficult to immediately recognize whether moisture is introduced into the interior of the pipe 410 simply by changing the relative humidity. Therefore, in monitoring the operation of the terminal box 400, monitoring the amount of water together with the relative humidity can immediately know whether the amount of moisture contained in the insulating oil 420 increases.

After generating the primary alarm, the controller 700 recalculates the amount of moisture contained in the insulating oil according to the measured relative humidity and temperature (S250).

In this case, the calculated moisture amount and the measured relative humidity are compared with a predetermined second threshold value and a predetermined second threshold value, respectively (S260). Here, the second threshold value and the second threshold value may be appropriately determined according to the type of the insulating oil, and may be determined to be larger than the first threshold value and the first threshold value. For example, when the insulating oil is polybutene, the second threshold may be determined to be approximately 30 ppm.

If the calculated moisture amount is equal to or greater than the predetermined second threshold value or the measured relative humidity is equal to or greater than the predetermined second threshold value, the control unit generates a secondary alarm (S270) and drives the end connection box 400 (S280).

On the other hand, when the calculated moisture amount is less than the predetermined second threshold value and the measured relative humidity is less than the predetermined second threshold value, the controller 700 sets the calculated moisture amount and the measured relative humidity to predetermined 1 threshold and a predetermined first threshold (S300). At this time, if the calculated moisture amount is equal to or greater than the predetermined first threshold value or the measured relative humidity is equal to or greater than the predetermined first threshold value, the control unit maintains the first alarm (S310).

On the other hand, when the calculated moisture amount is less than the predetermined first threshold value and the measured relative humidity is less than the predetermined first threshold value, the controller 700 cancels the first alarm (S330) And comparing the calculated moisture amount and the measured relative humidity with a predetermined first threshold value and a predetermined first threshold value, respectively.

The moisture sensor 600 of the above-described moisture monitoring system 800 can be utilized not only in the operation of the termination box 400 but also in filling the interior of the aerator pipe 410 with insulating oil.

That is, when the insulating pipe 410 is filled with the insulating oil, moisture may flow into the interior of the pipe 410. In order to prevent this, it is possible to previously remove moisture or foreign matter in the air inside the terminal connection box 400 by vacuuming the inside of the terminal connection box 400 before filling the insulation oil. Therefore, when the insulating oil is filled into the pipe 410, it is possible to prevent foreign matter such as moisture from flowing into the pipe 410. As described above, in order to vacuum-process the interior of the pipe 410, it is necessary to provide various facilities for the vacuum process, so that the cost of the process of connecting the terminal connection box 400 is increased and the operation time is prolonged . Therefore, filling the inside of the termination box 400 with the inert gas may be performed before filling the inside of the termination box 400 with the insulating oil. It is possible to prevent moisture or foreign matter contained in the air from flowing into the insulating oil by filling the inside of the aerator pipe 410 with an inert gas such as nitrogen and purging the air inside the aerator pipe 410.

In this case, in the embodiment of the present invention, a check valve (not shown) is provided on the upper part of the aerator 410 when the inert gas is purged, for example, by purging with nitrogen gas, The sensor 600 can be attached to measure the relative humidity of the nitrogen through the check valve. In this manner, the relative humidity of the measured nitrogen allows the injection timing of the insulating oil into the aerator pipe 410 to be determined.

12 is a flowchart showing a control procedure for monitoring the amount of water at the time of filling the insulating oil in the terminal box.

Referring to FIG. 12, the inside of the pipe 410 is purged by an inert gas such as nitrogen (S110). In this case, the inert gas may be injected through the lower metal fitting 470 under the upper pipe 410.

Next, the relative humidity of nitrogen discharged through the check valve is sensed by a moisture sensor 600 provided in a check valve on the upper side of the aerator 410 (S130).

The controller 700 compares the measured relative humidity with a predetermined threshold (S150).

At this time, if the measured relative humidity is lower than the threshold value, the interior of the aerator 410 is filled with the insulating oil 420 (S170).

On the other hand, when the measured relative humidity is greater than the threshold value, the nitrogen purge (S110) and the relative humidity of nitrogen are measured (S130) and compared with the threshold (S150).

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. . It is therefore to be understood that the modified embodiments are included in the technical scope of the present invention if they basically include elements of the claims of the present invention.

10. Conductor
100 ... power cable
400 .. Termination box
410 .. Affection
420 .. insulating oil
460 .. Electric field relief cone
600 ... Moisture sensor
610 ... sensing section
620 ... connection
800 ... Moisture monitoring system

Claims (28)

An end connection box into which one end of the power cable is inserted and the insulation oil is filled; And
A sensing unit positioned inside the termination box and including a sensor for sensing a moisture content of the insulating oil; And an end connection structure for connecting the end connection structure. The method according to claim 1,
The power cable comprising: a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer located outside the insulating layer,
Wherein the end connection box includes: an end pipe into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; And an electric field relieving cone that relaxes the electric field inside the pipe; / RTI >
Wherein the electric field relieving cone is electrically connected to the outer semiconductive layer; And an insulating portion surrounding the semiconductive portion,
Wherein the sensor is inserted into the termination box through the lower bracket. 3. The method of claim 2,
Wherein the sensor is located between the lower bracket and the triple point,
Wherein the triple point is a point where the insulating layer of the power cable, the insulating portion of the electric field relieving cone, and the semi-conducting portion of the electric field relieving cone are in contact with each other. The method of claim 3,
Wherein a distance between the lower metal fitting and the upper end of the sensor is not greater than a distance between the lower metal fitting and the triple point. The method of claim 3,
The external surface electric field of the pipe and the electric field at one end of the sensor are changed according to the position of the sensor inserted into the end connection case and the external surface electric field exceeds a predetermined electric field value, And the sensor is disposed in the termination junction box so that an electric field at one end of the sensor exceeds a predetermined electric field value and no discharge occurs in the insulating oil. 6. The method of claim 5,
Wherein the sensor is disposed in the termination box such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm. The method according to claim 1,
Wherein the sensor senses temperature and relative humidity to calculate the moisture content. 1. A moisture monitoring system for a terminal junction box in which one end of a power cable is inserted,
Wherein the moisture monitoring system includes a sensing unit for sensing a moisture content of the insulating oil in the terminal connection box. 9. The method of claim 8,
And a controller for determining whether the water content is calculated or continued based on the information of the sensing unit. 10. The method according to claim 8 or 9,
The power cable comprising: a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer located outside the insulating layer,
Wherein the end connection box includes: an end pipe into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; An electric field relieving cone for relieving an electric field inside said pipe; / RTI >
Wherein the electric field reduction cone is electrically connected to the outer semiconductive layer of the power cable; And an insulating portion surrounding the semiconductive portion,
Wherein the sensing unit is located between the lower bracket and the triple point,
Wherein the triple point is a point where the insulating layer of the power cable, the insulating portion of the electric field relieving cone, and the semi-conductive portion of the electric field relieving cone are in contact with each other. 11. The method of claim 10,
Wherein a distance between the lower metal fitting and the upper end of the sensing part is less than a distance between the lower metal fitting and the triple point. 11. The method of claim 10,
The external surface electric field of the pipe and the electric field at one end of the sensor are changed according to the position of the sensor inserted into the end connection case and the external surface electric field exceeds a predetermined electric field value, And the sensor is disposed in the end connection case so that an electric field at one end of the sensor exceeds a predetermined electric field value so that discharge does not occur in the insulating oil. 13. The method of claim 12,
Wherein the sensor is arranged in the termination junction box such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm. 10. The method according to claim 8 or 9,
Wherein,
Wherein data of a lookup table type is stored as a change in relative humidity with a change in temperature of the insulating oil. 15. The method of claim 14,
Wherein,
The temperature and the relative humidity of the insulating oil measured by the sensing unit and the moisture content of the insulating oil at the measured temperature from the lookup table. The method according to claim 10 or 11,
Wherein,
Comparing the calculated moisture content to a predetermined first threshold value, comparing the measured relative humidity to a predetermined first threshold value,
And generates a first alarm when the calculated moisture amount is equal to or higher than the predetermined first threshold value or the measured relative humidity is equal to or higher than the predetermined first threshold value. 17. The method of claim 16,
Wherein,
The temperature and the relative humidity of the insulating oil measured by the sensing unit when the calculated moisture amount is less than the predetermined first threshold value or the measured relative humidity is less than the predetermined first threshold value, And the water content of the insulating oil at the measured temperature is recalculated. 17. The method of claim 16,
Wherein,
Calculating the moisture content included in the insulating oil by the measured relative humidity and temperature after generating the first alarm,
Comparing the calculated moisture content to a predetermined second threshold value, comparing the measured relative humidity to a predetermined second threshold value,
Generating a second alarm when the calculated moisture amount is equal to or greater than the predetermined second threshold value or the measured relative humidity is equal to or greater than the predetermined second threshold value,
And stops the operation of the terminal connection box. 19. The method of claim 18,
Wherein,
And comparing the calculated moisture content and the measured relative humidity with a predetermined first threshold and a predetermined threshold if the calculated moisture content is less than the predetermined second threshold or the measured relative humidity is less than the predetermined second threshold, Again,
And maintains the first alarm when the calculated moisture amount is equal to or greater than a predetermined first threshold value or the measured relative humidity is equal to or greater than a predetermined first threshold value. 20. The method of claim 19,
Wherein,
And releases the first alarm when the calculated moisture amount is less than the predetermined first threshold value or the measured relative humidity is less than the predetermined first threshold value. 21. The method of claim 20,
Wherein,
Calculating the amount of water contained in the insulating oil by the measured relative humidity and temperature, and comparing the calculated moisture amount and the measured relative humidity with a predetermined first threshold and a predetermined first threshold, respectively Features a moisture monitoring system. 9. The method of claim 8,
Wherein the sensing unit senses a temperature and a relative humidity to calculate the moisture content. 1. A moisture monitoring method for a terminal connection box in which one end of a power cable is inserted and an insulating oil is filled,
A sensing step of sensing the moisture content of the insulating oil through an end sensor connected to the sensor; And
A control step of calculating a moisture content or continuing operation based on the information collected through the sensor; Wherein the moisture monitoring method comprises the steps of: 24. The method of claim 23,
The power cable comprising: a conductor layer; An inner semiconductive layer located outside the conductor layer; An insulating layer located outside the inner semiconductive layer; And an outer semiconductive layer located outside the insulating layer,
Wherein the end connection box includes: an end pipe into which an end portion of the power cable is inserted and an insulating oil is filled therein; An upper bracket disposed at an upper end of the eyelet; A lower bracket disposed at a lower end of the eye tube; And an electric field relieving cone that relaxes the electric field inside the pipe; / RTI >
Wherein the electric field relieving cone is electrically connected to an outer semiconductive layer of the power cable; And an insulating portion surrounding the semiconductor device,
Wherein the sensing is performed between the lower bracket and an insulating layer of the power cable, an insulating portion of the electric field relieving cone, and a triple point, which is a point where the half of the electric field relieving cone contacts with the sensing portion. 25. The method of claim 24,
Wherein the sensing is performed at a distance less than a distance between the lower bracket and the triple point in the sensing step. 26. The method of claim 25,
The external surface electric field of the pipe and the electric field at one end of the sensor are changed according to the position of the sensor inserted into the end connection case and the external surface electric field exceeds a predetermined electric field value, And the sensor is disposed in the termination box so that an electric field at one end of the sensor exceeds a predetermined electric field value and no discharge occurs in the insulating oil. 27. The method of claim 26,
Wherein the sensor is disposed within the termination enclosure such that the external surface electric field does not exceed 2.5 kV / mm and the electric field at one end of the sensor does not exceed 20 kV / mm. 24. The method of claim 23,
Wherein the sensing of the moisture content of the insulating oil in the sensing step is performed by measuring the temperature and the relative humidity of the insulating oil.

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