JP2010122029A - Current applying test method of power cable - Google Patents

Abstract

An electric power cable charging test method that can be satisfactorily tested without being affected by changes in outside air temperature, and a power cable charging test system used for carrying out the test method. provide.
An energizing test system 1 includes a conductor CT 3 for passing a current through a conductor 20 of a test cable 2 arranged in a closed loop, and a conductor energizing dummy cable 4 used for measuring the temperature of the conductor 20; With Further, the system 1 includes a metal layer energizing dummy cable 6 having a temperature adjusting metal layer 61, the temperature adjusting metal layer 61, an energizing metal layer 41 included in the dummy cable 4, and the test cable 2. The metal layer 21 provided on the outer periphery of the conductor 20 is connected by lead portions 62a, 62b, 62c to form a closed loop 60R, and a current is also passed through the metal layer 21. The temperature of the conductor 20 can be increased by heat generated by energization of the metal layer 21.
[Selection] Figure 1

Description

  The present invention relates to a power cable charging test method used for a power supply line, and a power cable charging test system suitable for carrying out this test method. In particular, the present invention relates to a current-carrying test method that is not easily affected by changes in outside air temperature.

  As a method for conducting an energization test of a power cable used for a power line, for example, a closed loop is formed by short-circuiting both ends of a test cable with a conductor member, a predetermined voltage is applied to the test cable, and a current is supplied to the closed loop. There is a way to flow. In order to energize the test cable, for example, an induced current by a current transformer (hereinafter referred to as CT) is used.

  When conducting a test for the purpose of investigating insulation characteristics by giving a predetermined temperature history to the test cable, the temperature of the conductor of the test cable is measured during energization. When a high voltage is applied to the conductor in the above test method, it is difficult to directly measure the temperature of the conductor. Therefore, a dummy cable and a transformer are prepared separately, and a dummy cable in which a high voltage is not applied by causing a current similar to the current flowing in the conductor of the test cable to flow through the dummy cable conductor due to the induced current from the test cable. The temperature is measured by (for example, FIG. 1 of Patent Document 1). Based on the measured temperature, the temperature change of the conductor accompanying energization is grasped, and ON / OFF of the current flowing through the test cable is controlled so that the conductor has a predetermined temperature.

JP 05-203690 A

  However, in the conventional test method, when the outside air temperature changes, it is necessary to change the amount of current flowing through the test cable as needed according to the outside air temperature, and the operability during the test is not good. It is difficult to accurately control the temperature.

  When the test cable is installed in the external environment (environment where temperature changes occur such as outdoors or indoors without air conditioning equipment) and the above energization test is performed, this change will occur if the ambient temperature of the test cable changes due to changes in the outside air temperature. As a result, the temperature of the conductor also changes. That is, since the temperature environment in which the test cable is placed is not stable, the temperature of the conductor accompanying energization cannot be accurately controlled. Therefore, based on the temperature information from the dummy cable, so that the temperature of the conductor becomes a predetermined temperature environment based on the temperature information from the dummy cable, so that the influence of the change in the outside air temperature can be eliminated and the temperature of the conductor accompanying energization can be controlled more accurately It is necessary to adjust the amount of current flowing through the conductor of the test cable. For example, when the outside air temperature is low, such as in winter, the amount of current is increased. However, since the temperature of the conductor of the test cable is increased by energization, when the outside air temperature changes, it is not easy to determine the adjustment amount of the current amount by eliminating the change in the outside air temperature. Since the outside air temperature changes even during the day, fine adjustment of the current amount is frequently required. Thus, in the conventional test method, since the control of the conductor temperature of the test cable is complicated, improvement in operability is desired. In particular, when conducting an energization test over a long period of time, since the outside air temperature changes depending on the season and weather, the number of adjustments increases.

  On the other hand, as a method of reducing the influence of the change in the outside air temperature on the test cable, it is conceivable to arrange a heat insulating material on the outer periphery of the test cable. However, in this case, once the temperature of the test cable is increased, the temperature is difficult to decrease, and a predetermined temperature history (temperature change rate, etc.) may not be appropriately given to the test cable.

  On the other hand, CIGRE Recommendations (Electra No. 189, 2000) is generally used as an energization test for DC cables such as DC submarine cables. In this test, it is necessary to change the cable temperature between the maximum operating temperature and room temperature (below 29 ℃) with the duty cycle set to 8 hours ON-16 hours OFF. As described above, when the outside air temperature is low in winter or the like, the conductor can reach a predetermined temperature by increasing the current value. However, when the current value is increased, the temperature in the vicinity of the conductor of the electrical insulating layer provided on the outer periphery of the conductor is high, but the temperature on the outer peripheral side decreases, and the temperature distribution (temperature difference) of the electrical insulating layer increases. Therefore, an excessive electric field (stress) is applied to the electrical insulating layer, and there is a possibility that appropriate evaluation cannot be performed. Therefore, it is desirable to reduce the influence accompanying the change in the outside air temperature particularly in the direct current test of the DC cable.

  Accordingly, one of the objects of the present invention is to provide a power cable charging test method that can be satisfactorily performed by a change in outside air temperature and that can perform a good charging test. Another object of the present invention is to provide a power cable charging test system suitable for carrying out the above charging test method.

  The present invention uses the test cable having a metal layer that can be energized on the outer periphery of the conductor and configured to pass a current through the metal layer when the conductor is energized. To achieve.

  Specifically, the method for testing the power cable of the present invention is a method for evaluating the performance of a power cable by passing a current in a state where a predetermined voltage is applied to a conductor of a test cable arranged in a closed loop. It is about. This test method comprises preparing a metal layer energizing dummy cable having a non-conducting conductor through which no current flows at the time of the test and a temperature adjusting metal layer provided on the outer periphery of the non-conducting conductor. The layer is electromagnetically connected to the metal layer provided on the outer periphery of the conductor of the test cable. The test method is such that when the conductor of the test cable is energized, a current is passed through the metal layer of the test cable and the temperature adjusting metal layer of the metal layer energization dummy cable, and the metal layer energization is performed. Measure the temperature of the metal layer for temperature adjustment of the dummy cable for the cable, and adjust the current to the metal layer of the cable under test so that the metal layer of the cable under test reaches a predetermined temperature based on the measured temperature To do.

  The present invention section energization test method having the above configuration can be implemented, for example, by constructing the following present invention section energization test system. The current application test system of the present invention relates to a system used for evaluating the performance of a power cable by passing a current in a state where a predetermined voltage is applied to a conductor of a test cable arranged in a closed loop. is there. This system includes a current transformer for conducting current through the conductor of the test cable and a conductor energizing dummy cable used for measuring the temperature of the conductor of the test cable, And a current transformer for the metal layer and a control unit. The conductor conducting dummy cable is composed of a temperature measuring conductor in which the same current as the conductor of the test cable flows due to electromagnetic induction from the test cable, and a conducting metal layer provided on the outer periphery of the temperature measuring conductor. Have The metal layer current transformer is a member for causing a current to flow through the metal layer provided on the outer periphery of the conductor of the test cable. The metal layer energizing dummy cable has a non-conducting conductor through which no current flows during the test, and a temperature adjusting metal layer provided on the outer periphery of the non-conducting conductor. The metal layer for energizing the dummy cable for energizing the conductor and the metal layer for adjusting the temperature of the dummy cable for energizing the metal layer are electromagnetically connected to the metal layer of the test cable, and are connected to the metal layer of the test cable. A current similar to the flowing current is passed. The control unit measures the temperature of the metal layer energization dummy cable when energizing the metal layer of the test cable, and based on this temperature, the test layer is configured so that the metal layer of the test cable becomes a predetermined temperature. It is a member for adjusting the current to the metal layer of the cable.

  According to the said structure, by supplying with electricity to the metal layer provided in the outer periphery of the conductor of a test cable, the inner side of a metal layer is warmed by the heat_generation | fever of a metal layer accompanying this electricity supply, and the temperature of a conductor rises. Therefore, if the current to the metal layer of the cable under test is controlled based on the temperature of the cable for energizing the metal layer so that the temperature of the metal layer becomes a predetermined temperature, the test object regardless of the outside temperature The temperature environment where the test cable is placed can be kept constant, or a desired simulated environment can be constructed. In particular, in the above configuration, by providing a metal layer energization dummy cable separately from the test cable, the temperature of the metal layer in an unaffected state due to the temperature change caused by energization of the conductor is appropriately measured. be able to. Therefore, even if the outside air temperature changes, the temperature of the metal layer can be controlled with high accuracy, so that the temperature environment in which the test cable is placed during the test can be stabilized. Moreover, according to the said structure, since a heat insulating material is not provided in the outer periphery of a test cable, cooling of the conductor of a test cable can be implemented according to the characteristic which the said cable has. Therefore, according to the above configuration, an accurate and stable temperature history can be given to the test cable, and it is expected that the test result is less affected by changes in the outside air temperature, that is, a more accurate and reliable test result can be obtained. The Further, according to the above configuration, since the temperature of the metal layer of the test cable can be easily controlled by providing the metal layer energization dummy cable as described above, the temperature environment in which the test cable is placed can be controlled. Easy. From the above, the above-described configuration can satisfactorily conduct an energization test regardless of the external environment (particularly the outside air temperature) and is excellent in operability during the test. For this reason, when the test method and test system of the present invention are used for the direct current test of the direct current cable, it is expected that an electric field (stress) more than necessary is hardly applied to the electrical insulating layer and appropriate evaluation can be performed.

  The conductor energizing dummy cable and the metal layer energizing dummy cable have the same configuration as the test cable. The lengths of the test cable and the dummy cable may be appropriately selected, and the dummy cable may be shorter than the test cable.

  In measuring the temperature of the metal layer energizing dummy cable, when a temperature measuring means such as a temperature sensor is directly arranged on the temperature adjusting metal layer, it is preferable to provide a temperature adjusting metal layer separately from the components of the cable. In the case of a dummy cable in which an insulating layer such as an anticorrosion layer is provided on the metal layer for temperature adjustment, if a temperature measuring means is arranged on this insulating layer, even if the dummy cable causes dielectric breakdown due to energization during the test, etc. Due to this influence, the temperature measuring means is hardly destroyed, and the temperature of the metal layer energizing dummy cable can be stably measured.

  The adjustment of the current may be performed by increasing or decreasing the current value itself, or by current ON / OFF control. The ON / OFF control is practical and can be suitably used. More specifically, a current value that can secure a necessary amount of heat is set, and when a current of this current value is passed, ON / OFF control is performed based on the measured temperature to control the temperature of the metal layer.

  The current may be adjusted so that the temperature of the metal layer of the test cable is maintained at a preset constant temperature during the test, or as appropriate during the test so that a desired simulated environment can be realized. The current may be adjusted by changing the temperature so that each temperature is set. By appropriately changing the temperature of the metal layer, for example, it is possible to perform a test that simulates a temperature change for a certain day of the season or a yearly temperature change.

  The metal layer for energization and the metal layer for temperature adjustment of the dummy cable may be connected to the metal layer of the test cable via a lead portion to form one closed loop, or the metal layer of the test cable Another closed loop may be formed in addition to the closed loop formed by the. When the former has a single closed loop, the current from the metal layer current transformer flows through the energizing metal layer and the temperature adjusting metal layer in the same manner as the metal layer of the test cable. When the latter has a separate closed loop, the main closed loop is formed by connecting the metal layer of the test cable with the lead part, and the energizing metal layer and the temperature adjusting metal layer are connected with the other lead part. Constructs a sub closed loop. A metal layer induction transformer may be provided, and an induction current from the main closed loop through which a current from the metal layer current transformer flows may be passed through the sub closed loop by the induction transformer. By incorporating a metal layer energizing dummy cable in a closed loop that is different from the metal layer of the test cable that is charged, even if dielectric breakdown occurs in the test cable during the test, this effect causes the temperature adjusting metal layer to There is no surge. For this reason, the structure including the sub closed loop can prevent the temperature measuring means from being broken by a surge or the like even if the temperature measuring means is provided in the temperature adjusting metal layer. Temperature can be measured stably.

  The power cable to be tested in the present invention can employ cables having various structures, and may be either a DC cable or an AC cable. Moreover, the cable which does not provide the metal layer as a component of a cable in the outer periphery of a conductor, or the cable which provides the metal layer as a component of a cable may be sufficient. Examples of the cable not including the former metal layer include a CV cable including an insulating layer made of cross-linked polyethylene on the outer periphery of the conductor. Examples of cables having a metal layer include solid cables and OF cables, which have an oil-insulated insulating layer on the outer periphery of the conductor and a metal sheath on the outer periphery of the oil-immersed insulating layer, and some other CV cables. Can be mentioned. The metal sheath is typically made of lead (submarine cable) or aluminum (OF cable). Some CV cables have corrugated stainless steel or aluminum sheaths that can be used for metal layers. When a cable including these metal layers is used as a test cable, a current may be passed through the metal layer, or a metal layer may be provided separately. For cables that do not have a metal layer, a separate metal layer can be used for the test cable. The metal layer is provided, for example, by extrusion or by arranging a metal tube on the outer periphery of the conductor.

  According to the method for energizing electricity test of the power cable of the present invention, it is difficult to be affected by the outside air temperature, and the energizing test can be performed satisfactorily. In addition, according to the power cable charging test system of the present invention, it can be suitably used for carrying out the charging test.

Embodiments of the present invention will be described below.
(Embodiment 1)
FIG. 1 is a schematic diagram showing an outline of the current-carrying test system of the present invention. In the drawings, the same reference numerals denote the same items. The electrical charging test system 1 evaluates the performance of a power cable having the same configuration as the test cable 2 by supplying a current with a predetermined voltage applied to the conductor 20 of the test cable 2 arranged in a closed loop. Used for charging test. A more specific configuration of the system 1 includes a conductor CT 3 for conducting current through the conductor 20 of the test cable 2, a conductor energizing dummy cable 4 used for measuring the temperature of the conductor 20, and a conductor A conductor inductive transformer 5 is provided that causes a current to flow through a conductor (temperature measurement conductor 40) included in the energizing dummy cable 4. The feature of this system 1 is that, in addition to the dummy cable 4 for conducting the conductor, a dummy cable 6 for conducting the metal layer is provided, and the metal layer 21 provided in the test cable 2 can be energized. is there. Hereinafter, each component will be described in more detail.

[Test cable]
The test cable 2 includes a conductor 20 and a metal layer 21 provided on the outer periphery of the conductor 20. Here, in order from the center, a solid cable including a conductor, an oil-immersed insulating layer (inner semiconductive layer, main insulating layer, outer semiconductive layer), lead coating (metal layer), and an anticorrosion layer is used. . All the cables in FIG. 1 show only conductors and metal layers.

  Terminal portions (not shown) are provided at both ends of the test cable 2, and insulating cylinders 21 c are provided at both ends of the metal layer 21. Both ends of the conductor 20 are connected via a conductor member 22. By being short-circuited by the conductor member 22, the conductor 20 of the test cable 2 forms a closed loop 20R.

  A conductor CT3 is disposed on the conductor 20, and a predetermined current is caused to flow by electromagnetic induction during the test. In addition, a predetermined voltage is applied to the conductor 20 at the time of the test by a power application device (not shown).

[Closed loop for temperature measurement]
When high voltage is applied to the conductor 20 of the test cable 2, it is difficult to directly measure the temperature of the conductor 20, so the system 1 uses the conductor of the conductor energizing dummy cable 4 (temperature measurement conductor 40). Then, the temperature of the conductor 20 of the test cable 2 is measured. The conductor energizing dummy cable 4 comprises the temperature measuring conductor 40 and a metal layer (metal layer for energization) 41 provided on the outer periphery of the conductor 40, and has the same configuration as the test cable 2. . Here, the above-described solid cable is cut short. A heat insulating material is not disposed on the outer periphery of the conductor energizing dummy cable 4.

  Both ends of the temperature measuring conductor 40 of the conductor energizing dummy cable 4 are connected by the lead portions 42 to form a closed loop 40R. The energizing metal layer 41 at both ends of the conductor energizing dummy cable 4 is provided with terminal portions 43 for attaching lead portions 62a and 62c described later.

  A conductor induction transformer 5 is disposed on the lead portion 42 and the conductor 20 of the test cable 2. A current (inductive current) similar to that of the conductor 20 is caused to flow through the lead portion 42 by electromagnetic induction from the conductor 20 of the test cable 2 through the conductor induction transformer 5. That is, the induced current is passed through the temperature measuring conductor 40 connected to the lead portion 42. Since a high voltage is not applied to the closed loop 40R including the temperature measurement conductor 40 and the lead portion 42 by the voltage applying device, the temperature measurement means 44 disposed in the center of the temperature measurement conductor 40 causes the conductor 40 to The temperature can be measured. The measured temperature can be regarded as the temperature of the conductor 20 of the test cable 2.

[CT (current transformer), induction transformer]
Here, a general CT or induction transformer used for the energization test is used. The number of CTs and induction transformers shown in FIG. 1 is an example, and the number of conductor CT3, conductor induction transformer 5, and metal layer CT7 described later is the conductor 20 of the test cable 2 (closed loop 20R), for temperature measurement It may be selected as appropriate so that a predetermined current flows through the conductor 40 (closed loop 40R) and a temperature adjusting metal layer 61 (closed loop 60R) described later.

[Closed loop for metal layer energization]
In this system 1, during the test, not only the conductor 20 of the test cable 2 but also the metal layer 21 provided on the outer periphery of the conductor 20 is caused to flow, and this energization causes the metal layer 21 to generate heat and the test cable 2. The temperature is adjusted (increased) to reduce the change in the temperature environment in which the test cable 2 is placed as the outside air temperature changes. Therefore, the system 1 includes a closed loop 60R having the metal layer 21 and a metal layer CT7 for passing a current through the closed loop 60R, and regardless of energization of the conductor 20 of the test cable 2, the test is performed. In order to easily adjust the current to the metal layer 21 in order to set the temperature environment of the cable 2 to a predetermined temperature, a metal layer energization dummy cable 6 is separately provided.

  The metal layer energizing dummy cable 6 includes a non-conducting conductor 60 through which no current flows during the test and a metal layer (temperature adjusting metal layer) 61 provided on the outer periphery of the conductor 60. It is the same composition as. Here, the above-described solid cable is cut short. The temperature adjusting metal layers 61 at both ends of the metal layer energizing dummy cable 6 are provided with terminal portions 63 for attaching lead portions 62a and 62b described later. Further, here, a temperature measuring means 64 such as a temperature sensor is disposed on the outer periphery (on the anticorrosion layer) of the metal layer energizing dummy cable 6, and further, in order to make it less susceptible to the influence of sunlight, wind, etc. A protective tape is wound. In the case where a metal pipe is separately arranged on the outer periphery of the test cable 2 and the dummy cables 4 and 6, the temperature measuring means 64 is arranged directly on the metal pipe provided on the metal layer energizing dummy cable 6 and the temperature is set. May be measured. Note that a heat insulating material is not disposed on the outer periphery of the metal layer energization dummy cable 6.

  The terminal part 63 on one end side of the dummy cable 6 for energizing the metal layer and the terminal part 43 on one end side of the dummy cable 4 for energizing the conductor are connected by the lead part 62a, and the other end side of the dummy cable 6 for energizing the metal layer 6 is connected. The terminal portion 63 and the terminal portion 23 provided on the metal layer 21 on one end side of the test cable 2 are connected by the lead portion 62b, and the terminal portion 43 on the other end side of the conductor energizing dummy cable 4 and the test cable 2 The terminal portion 23 provided on the metal layer 21 on the other end side is connected by the lead portion 62c to form a closed loop 60R.

  During the test, a current is passed through the temperature adjusting metal layer 61 of the metal layer conducting dummy cable 6 by the metal layer CT 7 arranged in the lead portion 62c (no current is passed through the non-conducting conductor 60). At this time, a similar current is passed through the metal layer 21 of the test cable 2 to increase the temperature inside the test cable 2. With this configuration, the temperature adjusting metal layer 61 is not affected by the heat generated by the conductor 20 when the conductor 20 of the test cable 2 is energized, and the temperature of the metal layer energizing dummy cable 6 is measured by the temperature measuring means 64. Can do. This temperature corresponds to the temperature of the temperature adjusting metal layer 61, that is, corresponds to the metal layer 21 of the test cable 2. The controller (not shown) controls ON / OFF of the metal layer CT7 so that the temperature of the metal layer 21 becomes a predetermined temperature, thereby adjusting the current flowing through the closed loop 60R. By adjusting the current, the temperature environment in which the test cable 2 is placed can be stabilized at a predetermined temperature environment.

  Here, the metal layer CT7 is disposed on the lead portion 62c, but the lead portions 62a and 62b may be disposed, and the metal layer CT7 may be disposed on any location. Further, in short-circuiting the metal layer 21 of the test cable 2 by the lead parts 62a, 62b, 62c, the components of the closed loop 60R, that is, the lead parts 62a, 62b, 62c, the metal layer 21 of the test cable 2, and the dummy By arranging the energizing metal layer 41 and the temperature adjusting metal layer 61 of the cables 4 and 6 as close as possible so as to reduce the cross-sectional area of the closed loop 60R, mutual interference between the conductor current and the metal layer current can be reduced. It is preferable. For example, if the lead portions 62a, 62b, 62c are arranged as close as possible to the metal layer 21, the current induced in the metal layer 21 can be reduced when a current is passed through the conductor 20 of the test cable 2.

[Examination procedure]
A procedure for constructing the system 1 having the above-described configuration in an external environment (for example, outdoors) and performing a charging test will be described below.

  A reference temperature of the temperature environment in which the conductor 20 of the test cable 2 is placed is set in advance (for example, 30 ° C.). When the temperature of the conductor 20 is lower than a predetermined reference temperature in winter, night, early morning, rainy weather, etc., a closed loop 60R comprising the metal layers 21, 41, 61 and the lead portions 62a, 62b, 62c by the CT7 for metal layers An electric current is passed, and the temperature of the conductor 20 is raised by the heat generation of the metal layer 21 due to this energization. The temperature of the metal layer energizing dummy cable 6 is measured by the temperature measuring means 64, and based on the measured temperature, the control unit performs ON / OFF control so that the temperature of the metal layer 21 becomes a predetermined temperature. Adjust the current to layer 21. Since the temperature measured by the temperature measuring means 64 corresponds to the temperature of the metal layer 21 of the test cable 2 when the conductor 20 is in a non-energized state, the environment in which the test cable 2 is placed based on this temperature Conditions (such as current values) that prevent the temperature from falling below the reference temperature can be set. Whether or not the conductor 20 of the test cable 2 is at the reference temperature can be confirmed by the temperature measuring means 44 of the conductor energizing dummy cable 4.

  A predetermined voltage is applied to the conductor 20 of the test cable 2 by means of a voltage applying device (not shown), and a current is passed through the conductor CT 3 to perform a charging test. At this time, a current having the same magnitude as the current flowing in the conductor 20 of the test cable 2 flows through the closed loop 40R including the conductor energizing dummy cable 4 due to electromagnetic induction by the conductor induction transformer 5. In this state, the temperature of the temperature measuring conductor 40 is measured by the temperature measuring means 44. The temperature measured at this time corresponds to the temperature of the conductor 20 of the test cable 2. Therefore, the temperature of the temperature measuring conductor 40, that is, the temperature of the conductor 20 of the test cable 2 is measured at any time by the temperature measuring means 44 so that a predetermined temperature history is given to the conductor 20 of the test cable 2, Based on this measurement result, the conductor CT3 is turned on / off.

  At the time of the energizing test, as described above, a current is also passed through the closed loop 60R by the metal layer CT7 so that the temperature of the metal layer 21 of the test cable 2 becomes a predetermined temperature. With this configuration, the temperature environment in which the test cable 2 is placed can be stabilized even when the outside air temperature changes over time during the test. Alternatively, by appropriately adjusting the temperature of the metal layer 21, the temperature environment in which the test cable 2 is placed can be changed to a desired simulated environment. In the energization test, for example, the soundness of the cable when a predetermined temperature history is given is evaluated.

[effect]
Since the above-mentioned charging test system 1 is configured to energize the metal layer 21 in addition to the conductor 20 of the test cable 2 during the test, even if the outside air temperature changes, heat is generated by energizing the metal layer 21. By using this, the surface temperature of the test cable 2 and the temperature of the metal layer 21 can be set to predetermined temperatures. Therefore, the system 1 can maintain the temperature environment where the test cable 2 is placed in a constant state or control it to a desired temperature state. In addition, in this system 1, since the heat insulating material is not arranged on the outer periphery of the test cable 2, the decrease in the temperature of the conductor 20 is not delayed after the energization of the test cable 2 is stopped. Therefore, compared with the conventional method of adjusting the CT3 for the conductor according to the change of the outside temperature and changing the amount of current to the conductor 20 of the test cable 2 and the method of arranging the heat insulating material, this system 1 is It is expected that an accurate and stable temperature history can be imposed on the test cable, and a highly reliable test result can be obtained. For example, when conducting an energization test using the system 1 on a DC cable, an electric field (stress) more than necessary is not applied to the electrical insulation layer, so it is expected that a highly reliable test result will be obtained. The Further, the system 1 includes a metal layer energizing dummy cable 6 in addition to the conductor energizing dummy cable 4, and is configured so as not to energize the conductor (non-conducting conductor 60) included in the dummy cable 6. The temperature adjusting metal layer 61 provided in the dummy cable 6 is not substantially affected by the conduction of the conductor. Therefore, the temperature that is not affected by the conduction of the conductor can be measured by the metal layer conduction dummy cable 6, and this temperature can be handled as the ambient temperature of the test cable. In addition, since the current value can be easily set and controlled to the metal layer 61 for temperature adjustment based on the temperature measured by the dummy cable 6 for energizing the metal layer, the system 1 has excellent operability during the test. .

[Test example]
The charging test system shown in FIG. 1 was actually constructed, and the charging test was performed according to the procedure described above. The result is shown in FIG.

  By performing ON / OFF control by the control unit according to the above procedure, the current to the metal layer for temperature adjustment of the metal layer energization dummy cable is adjusted, and the temperature of the metal layer energization dummy cable is kept constant. 2, even when the outside air temperature changes over time, the conductor of the test cable is substantially unaffected by the change in the outside temperature, and the conductor of the test cable is It can be seen that the temperature history can be given. Further, by energizing the energizing metal layer of the conductor energizing dummy cable, the temperature of the conductor and metal layer of the test cable can be monitored as shown in FIG. 1 includes a metal layer energizing dummy cable having a non-conducting conductor as described above, and by measuring the temperature of this dummy cable, the conductor energizing as shown in FIG. It is possible to grasp the temperature of the metal layer in a state where it is not substantially affected by this. Therefore, the current to the metal layer can be appropriately controlled based on the measured temperature of the dummy cable for energizing the metal layer, and as a result, the temperature environment in which the test cable is placed can be kept constant. Therefore, when a predetermined temperature history is given, a highly reliable test environment (conditions) as shown in Fig. 2 reduces the complexity of adjusting the conductor temperature control (current control) compared to the conventional method. And can be easily constructed.

(Embodiment 2)
FIG. 3 is a schematic diagram showing an outline of another current section electrical test system. As in the system 1 of the first embodiment, the charging system 10 applies a predetermined voltage to the conductor 20 of the test cable 2 arranged in a closed loop, and allows the current to flow, similar to the test cable 2. It is used for the energization test to evaluate the performance of the power cable in the configuration. Similarly to the system 1 of the first embodiment, the system 10 includes a test cable 2, a conductor CT 3, a conductor energizing dummy cable 4, a conductor inductive transformer 5, and a metal layer energizing dummy cable 6. In the system 1 of the first embodiment, one closed loop including the metal layer 21 of the test cable 2 and the metal layers 41 and 61 of both dummy cables 4 and 6 is provided as one. In contrast, the system 10 separates a closed loop (main closed loop 60Rm) including the metal layer 21 of the test cable 2 and a closed loop (sub closed loop 60Rs) including the metal layers 41 and 61 of both dummy cables. Prepare for. Hereinafter, this difference will be mainly described, and the other configurations and the like are the same as those in the first embodiment, and thus description thereof will be omitted.

[Main closed loop]
The terminal portion 23 on one end side of the test cable 2 and the terminal portion 23 on the other end side are connected by a lead portion 62d to form a main closed loop 60Rm. A metal layer CT7 is arranged in the middle of the lead part 62d. With this configuration, a current flows through the metal layer 21 of the test cable 2 through the metal layer CT7. The direction of current flowing through the metal layer 21 (white arrow) is opposite to the direction of current flowing through the lead portion 62d (black arrow).

[Sub closed loop]
The terminal part 63 on one end side of the dummy cable 6 for energizing the metal layer and the terminal part 43 on one end side of the dummy cable 4 for energizing the conductor are connected by the lead part 62a, and the other end side of the dummy cable 6 for energizing the metal layer 6 is connected. The terminal portion 63 and the terminal portion 43 on the other end side of the conductor energizing dummy cable 4 are connected by the lead portion 62e to form the sub closed loop 60Rs. The metal layer induction transformer 8 is disposed on a part of the lead part 62e and a part of the lead part 62d constituting the main closed loop 60Rm. With this configuration, the metal layers 41 and 61 constituting the sub closed loop 60Rs are subjected to electromagnetic induction from the main closed loop 60Rm (lead portion 62d) via the metal layer induction transformer 8, so that the metal layer 21 of the test cable 2 is provided. A current (inductive current) similar to the current flowing through the

  The test cable 2 and the dummy cables 4 and 6 are both solid cables similar to those in the first embodiment. In measuring the temperature of the metal layer energizing dummy cable 6, the temperature measuring means 64 may be attached to the anticorrosion layer provided on the outer periphery of the lead coating (temperature adjusting metal layer 61) as in the first embodiment. You may attach to a lead coat.

[effect]
Similar to the system 1 of the first embodiment, the system 10 having the above configuration is configured so that the test cable 2 is energized not only in the conductor 20 of the test cable 2 but also in the metal layer 21 during the energization test. In addition to stabilizing the temperature environment, the provision of the metal layer energizing dummy cable 6 makes it easy to control the temperature of the metal layer 21 and provides excellent operability. In addition, this system 10 is configured to adjust the temperature of the main closed loop 60Rm to which the metal layer 21 of the test cable 2 belongs and the dummy cable 6 for energizing the metal layer used to control the temperature environment in which the test cable 2 is placed. The sub closed loop 60Rs to which the metal layer 61 belongs is not directly connected to the lead portion, but is separately provided, and the induced current from the main closed loop 60Rm is passed through the sub closed loop 60Rs. With this configuration, the sub closed loop 60Rs can reduce the influence of the conductor current. For example, even if a dielectric breakdown occurs in the test cable 2 during the test, a surge does not enter the temperature adjusting metal layer 61 due to this influence, so the temperature measuring means 64 is attached to the temperature adjusting metal layer 61. Even if it exists, the temperature measurement means 64 is not destroyed, and the temperature of the metal layer conduction dummy cable 6 can be measured stably.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration. For example, the test cable can be an OF cable or a CV cable. In the case of a CV cable that does not have a metal layer as a component of the cable, the metal layer is provided by extrusion or the like. Further, the energization current may be an alternating current as in the above embodiment, or may be a direct current. Even if a direct current is used, it is difficult to be affected by changes in the outside air temperature by passing a current through the metal layer, and a good energization test can be performed.

  The method for applying a power cable to the power cable of the present invention can be suitably used for a power cable applied to a power supply line. The power cable charging test system of the present invention can be suitably used for carrying out the above-described power charging test method of the present invention. In particular, the test method and test system of the present invention can be suitably used for a DC cable.

1 is a schematic diagram illustrating an outline of a power cable charging / discharging test system shown in Embodiment 1. FIG. It is a graph which shows the time-dependent change of the temperature of the conductor of the dummy cable for conducting electricity, the temperature of the metal layer, and the temperature of the metal layer conducting cable when conducting the conducting test using the charging test system shown in the embodiment. . 5 is a schematic diagram showing an outline of a power cable charging / discharging test system shown in Embodiment 2. FIG.

Explanation of symbols

1,10 Section test system 2 Test cable 20 conductors
20R, 40R, 60R, 60Rm, 60Rs Closed loop 21 Metal layer 21c Insulating cylinder
22 Conductor member 23, 43, 63 Terminal part 3 Conductor CT
4 Conductor conduction dummy cable 40 Temperature measurement conductor 41 Conduction metal layer
42,62a, 62b, 62c, 62d, 62e Lead 44,64 Temperature measuring means
5 Inductive transformer for conductor 6 Dummy cable for metal layer energization
60 Non-conducting conductor 61 Metal layer for temperature adjustment 7 CT for metal layer
8 Induction transformer for metal layer

Claims (7)

A power cable charging / discharging test method for evaluating the performance of a power cable by passing a current in a state where a predetermined voltage is applied to a conductor of a test cable arranged in a closed loop,
Prepare a metal layer energization dummy cable having a non-conducting conductor through which no current flows during the test and a temperature adjusting metal layer provided on the outer periphery of the non-conducting conductor,
Electromagnetically connecting the metal layer for temperature adjustment and the metal layer provided on the outer periphery of the conductor of the test cable,
At the time of energizing the conductor of the test cable, a current is passed through the metal layer of the test cable and the temperature adjusting metal layer, and the temperature of the dummy cable for energizing the metal layer is measured. Based on this temperature A method for applying an electric current to a power cable, wherein a current to the metal layer of the test cable is adjusted so that the metal layer of the test cable has a predetermined temperature.   2. The method of applying a power cable to a power cable according to claim 1, wherein the current is adjusted so that the temperature of the metal layer of the test cable is maintained at a constant temperature. A power cable charging test system used when evaluating the performance of a power cable by passing a current in a state where a predetermined voltage is applied to a conductor of the test cable arranged in a closed loop,
A current transformer for a conductor for passing a current through the conductor of the test cable having a metal layer on the outer periphery of the conductor;
A current transformer for a metal layer for passing a current through the metal layer of the test cable;
A temperature measuring conductor through which a current similar to that of the conductor of the test cable flows due to electromagnetic induction from the test cable, and a current similar to the current flowing through the metal layer provided on the outer periphery of the temperature measuring conductor. A conductor energizing dummy cable having a current-carrying metal layer;
A metal layer energizing dummy cable having a non-conducting conductor through which no current flows during the test, and a temperature adjusting metal layer that is provided on the outer periphery of the non-conducting conductor and through which a current similar to the current flowing through the metal layer flows.
The temperature of the dummy cable for energizing the metal layer is measured at the time of energizing the metal layer of the test cable, and based on this temperature, the metal layer of the test cable is set to a predetermined temperature. A power cable charging / discharging test system comprising a control unit for adjusting a current to the metal layer. A main closed loop in which a metal layer of the test cable is connected by a lead portion, and a current is passed by the current transformer for the metal layer,
A sub closed loop formed by connecting the energizing metal layer and the temperature adjusting metal layer with another lead portion;
4. The electric power cable imposing test system according to claim 3, wherein the sub closed loop includes a metal layer induction transformer for flowing an induced current from the main closed loop.   The test cable and the dummy cables are any of a solid cable, an OF cable, and a CV cable having a metal sheath on an outer periphery of a conductor, and the metal layer is the metal sheath. 5. A power cable charging test system according to claim 3 or 4.   6. The power cable charging / discharging test system according to claim 3, wherein the test cable and the dummy cables are provided with a metal layer separately on an outer periphery of the cable.   The power cable charging / discharging test system according to any one of claims 3 to 6, wherein the test cable and the dummy cables are DC cables.

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