CN113805101A - Cable cross interconnection system connection state testing method and testing device - Google Patents
Cable cross interconnection system connection state testing method and testing device Download PDFInfo
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Abstract
The invention relates to the technical field of power transmission and transformation equipment, in particular to a method and a device for testing the connection state of a cable cross interconnection system, which comprises the following steps: selecting two signals with frequencies different from power frequency or field interference frequency, respectively coupling A, B, C same-axis cables of the cable cross interconnection system, and testing the voltage and current values input each time; a, B, C current signals responding in the same axial cable when signals are input each time through coupling induction, and the current value of the lead of the coaxial cable is calculated; calculating impedance values of three sections of the cross interconnection system according to the input voltage value and the calculated coaxial cable lead current value, and calculating resistance values of the three sections according to the relationship between the impedance and the resistance and the inductance; and judging the connection state of the cable cross interconnection system according to the resistance value of each section or the ratio of any two sections of resistance values. The invention can detect the electric connection state of the cable cross interconnection system in a live-line and power-off manner, and has simple and convenient operation and high detection efficiency.
Description
Technical Field
The invention relates to the technical field of power transmission and transformation equipment, in particular to a method and a device for testing the connection state of a cable cross interconnection system.
Background
At present, the connection defect of a cable cross interconnection grounding system is easy to cause cable faults caused by metal suspension discharge in a cable aluminum sheath or a cable accessory, and the electrical connection is complicated because the cable cross interconnection length is long, and the cable metal sheath in an interconnection section is connected with an accessory tail pipe and a grounding box copper bar.
Because a current exists in a cable inner conductor when the cables are in cross connection and induced current correspondingly exists on the outer surface of a cable sheath, when the traditional detection method is used for detecting the state of a cable cross connection system, the cross connection system can be disassembled for testing only when a line is out of service so as to avoid the influence caused by the induced current of the cable sheath, and the testing method has poor timeliness and limitation.
In view of the above problems, the designer is actively making research and innovation based on years of abundant practical experience and professional knowledge in engineering application of such products and cooperating with the application of theory, so as to create a method and a device for testing the connection state of the cable cross interconnection system, so that the method and the device are more practical.
Disclosure of Invention
The invention provides a method and a device for testing the connection state of a cable cross interconnection system, thereby effectively solving the problems in the background art.
In order to achieve the purpose, the invention adopts the technical scheme that: a method and a device for testing the connection state of a cable cross-connection system comprise the following steps:
the method comprises the following steps:
the method comprises the following steps: selecting two signals with frequencies different from power frequency or field interference frequency, wherein the frequencies are respectively F1 and F2, coupling the two signals into A, B, C same-axis cables of a cable cross interconnection system respectively in sequence, and testing the voltage and current values input each time;
step two: when signals are input every time, current signals responding to the same axial cable are coupled and induced A, B, C, and the current value of the lead of the coaxial cable is calculated through the characteristic that the current vector is unchanged;
step three: calculating impedance values of three sections of the cross interconnection system according to the input voltage value and the calculated coaxial cable lead current value, and calculating resistance values of the three sections of the cross interconnection system according to the relationship between the impedance and the resistance and the inductance;
step four: and judging the connection state of the cable cross interconnection system according to the resistance value of each section or the ratio of any two sections of resistance values.
Further, in the second step, the current value of the coaxial cable lead is calculated by using the following formula:
wherein i is a test frequency category, j is a test frequency, IA _ Fij, IB _ Fij and IC _ Fij are currents responded in A, B, C three-phase coaxial cables when Fi signals are injected in a coupling mode, and IA _ B _ Fij, IB _ C _ Fij and IC _ A _ Fij are lead currents A-B, B-C, C-A in the coaxial cables respectively;
when i is set to 1, injecting an F1 frequency signal; when i is 2, injecting an F2 frequency signal;
when j is set to 1, a signal is injected into the phase A in a coupling mode; when j is 2, coupling and injecting signals into the phase B; when j is 3, a signal is injected to the C phase.
Further, in the third step, the impedance value of each section of the cross-interconnected system is calculated by using the following formula: obtained from Uij Fi I Fij:
-IA_B_Fi1*Z1_Fi+IC_A_Fi1*Z3_Fi＝2*UFi1
-IA_B_Fi2*Z1_Fi+IB_C_Fi2*Z2_Fi＝2*UFi2
-IB_C_Fi3*Z2_Fi+IC_A_Fi3*Z3_Fi＝2*UFi3
wherein Uij is an input voltage effective value, I _ Fij is an input current effective value, I is a test frequency category, j is the number of tests, and k is a proportionality coefficient;
z1_ Fi, Z2_ Fi and Z3_ Fi respectively represent impedances of different sections when a signal with Fi frequency is injected, Z1 is impedance of sections A1-B2-C3 of a cross interconnection system, Z2 is impedance of sections A2-B3-C1 of the cross interconnection system, and Z3 is impedance of sections A3-B1-C2 of the cross interconnection system;
UFi1, UFi2, and UFi3 are voltage values input when signals are coupled and injected to the a phase, the B phase, and the C phase, respectively.
Further, in the third step, the following formula is used to calculate the resistance values of the three sections of the cross-connect system:
Zn_F1^2＝Zn_Rn^2+(2*π*F1)^2*Zn_Ln^2
Zn_F2^2＝Zn_Rn^2+(2*π*F2)^2*Zn_Ln^2
wherein Zn _ F1 and Zn _ F2 represent impedances of different segments at frequencies F1 and F2, respectively;
zn _ Rn represents the resistance at different segments, Zn _ Ln represents the inductance at different segments;
n is 1, 2 or 3, and represents A1-B2-C3 when n is 1; when n is 2, the segment A2-B3-C1 is shown, and when n is 3, the segment A3-B1-C2 is shown.
Further, in the fourth step, when the resistance of any section is greater than or equal to 1 Ω or the ratio of each section exceeds 2, the connection defect of the cable cross-connection grounding system is determined.
Further, in the second step, the positive direction of the test current is selected to be the direction of the side of the grounding box closest to or farthest from the test current.
The invention also includes a cable cross-connect system connection state testing device, including:
the input module is used for respectively coupling and inputting signals with different frequencies to cables with the same axis A, B, C of the cable cross interconnection system and testing input voltage and input current;
an output module that simultaneously couples the induction to A, B, C coax cables of the cross-cable interconnect system and outputs A, B, C current signals in response in the coax cables.
Further, the input module includes:
the system comprises a variable frequency power supply, signal injection equipment, input voltage test equipment and input current test equipment which are electrically connected, wherein the variable frequency power supply provides the variable frequency power supply for the signal injection equipment;
the output module includes: the device comprises three coupling sensors and output current testing equipment, wherein the three coupling sensors are respectively sleeved at different sections of a cable cross interconnection system and respectively perform coupling induction, and the output current testing equipment tests response currents in the different sections through the coupling sensors.
Further, the input voltage testing equipment and the input current testing equipment are alternating current measuring equipment, and the accuracy is not lower than 0.2 level.
Further, the accuracy of the output current testing equipment is not lower than 0.5 level.
The invention has the beneficial effects that: according to the invention, the coupling input and coupling induction modes are adopted, and the two input signal frequencies are different from the power frequency or the field interference frequency, so that the two input signal frequencies are separated from the induced current frequency existing in the cable, the interference of the induced current in the cable is avoided, the resistance value is finally calculated by calculating the impedance value, and the connection state of the cable cross interconnection system is judged according to the resistance value or the ratio of the resistance values, so that the electric connection state of the cable cross interconnection system can be detected in an electrified and power-cut manner, the operation is simple and convenient, the detection efficiency is high, and the application prospect is good.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic diagram of a cable cross-connect system;
FIG. 3 is an equivalent circuit diagram of a cable grounding system;
FIG. 4 is a schematic structural diagram of a testing apparatus;
FIG. 5 is a diagram of test A coaxial cable input signals and test wiring;
FIG. 6 is a schematic diagram of the testing of the input signal and the test connection of the same axis cable A in FIG. 5.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like are based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
As shown in fig. 1 to 3: a method for testing the connection state of a cable cross-connection system comprises the following steps:
the method comprises the following steps: selecting two signals with frequencies different from power frequency or field interference frequency, wherein the frequencies are respectively F1 and F2, coupling the two signals into A, B, C same-axis cables of a cable cross interconnection system respectively in sequence, and testing the voltage and current values input each time;
step two: when signals are input every time, current signals responding to the same axial cable are coupled and induced A, B, C, and the current value of the lead of the coaxial cable is calculated through the characteristic that the current vector is unchanged;
step three: calculating impedance values of three sections of the cross interconnection system according to the input voltage value and the calculated coaxial cable lead current value, and calculating resistance values of the three sections of the cross interconnection system according to the relationship between the impedance and the resistance and the inductance;
step four: and judging the connection state of the cable cross interconnection system according to the resistance value of each section or the ratio of any two sections of resistance values.
By adopting the coupling input and coupling induction modes, and the two input signal frequencies are different from the power frequency or the field interference frequency, so that the two input signal frequencies are separated from the induced current frequency existing in the cable, the interference of the induced current in the cable is avoided, the resistance value is finally calculated by calculating the impedance value, the connection state of the cable cross interconnection system is judged according to the resistance value or the ratio of the resistance values, the electric connection state of the cable cross interconnection system can be detected in an electrified and power-cut manner, the operation is simple and convenient, the detection efficiency is high, and the cable cross interconnection system has a good application prospect.
In this embodiment, in the second step, the current value of the coaxial cable lead is calculated by using the following formula:
wherein i is a test frequency category, j is a test frequency, IA _ Fij, IB _ Fij and IC _ Fij are currents responded in A, B, C three-phase coaxial cables when Fi signals are injected in a coupling mode, and IA _ B _ Fij, IB _ C _ Fij and IC _ A _ Fij are lead currents A-B, B-C, C-A in the coaxial cables respectively;
when i is set to 1, injecting an F1 frequency signal; when i is 2, injecting an F2 frequency signal;
when j is set to 1, a signal is injected into the phase A in a coupling mode; when j is 2, coupling and injecting signals into the phase B; when j is 3, a signal is injected to the C phase.
Because the induced current exists in the cable, after a signal is input to the cable, the response current detected in the cable is the combination of the input current and the induced current, and the lead current in the coaxial cable is calculated through the characteristic that the current vector is unchanged, so that the influence of the induced current is removed.
As a preference of the above embodiment, in step three, the impedance value of each section of the cross-connect system is calculated by using the following formula:
obtained from Uij Fi I Fij:
-IA_B_Fi1*Z1_Fi+IC_A_Fi1*Z3_Fi＝2*UFi1
-IA_B_Fi2*Z1_Fi+IB_C_Fi2*Z2_Fi＝2*UFi2
-IB_C_Fi3*Z2_Fi+IC_A_Fi3*Z3_Fi＝2*UFi3
wherein Uij is an input voltage effective value, I _ Fij is an input current effective value, I is a test frequency category, j is the number of tests, and k is a proportionality coefficient;
z1_ Fi, Z2_ Fi and Z3_ Fi respectively represent impedances of different sections when a signal with Fi frequency is injected, Z1 is impedance of sections A1-B2-C3 of the cross interconnection system, Z2 is impedance of sections A2-B3-C1 of the cross interconnection system, and Z3 is impedance of sections A3-B1-C2 of the cross interconnection system;
UFi1, UFi2, and UFi3 are voltage values input when signals are coupled and injected to the a phase, the B phase, and the C phase, respectively.
In the cable cross-connection system, the cable is actually three sections, specifically: the section A1-B2-C3, the section A2-B3-C1 and the section A3-B1-C2 are all provided with an impedance, when actual coupling induction is carried out, every two of the three sections are combined and induced, therefore, induced current is the sum of every two combinations, and the impedance value of each section is calculated according to input voltage and input current through a simultaneous equation.
As a preference of the above embodiment, in the third step, the following formula is used to calculate the resistance value of the cross-connected system in three sections:
Zn_F1^2＝Zn_Rn^2+(2*π*F1)^2*Zn_Ln^2
Zn_F2^2＝Zn_Rn^2+(2*π*F2)^2*Zn_Ln^2
wherein Zn _ F1 and Zn _ F2 represent impedances of different segments at frequencies F1 and F2, respectively;
zn _ Rn represents the resistance at different segments, Zn _ Ln represents the inductance at different segments;
n is 1, 2 or 3, and represents A1-B2-C3 when n is 1; when n is 2, the segment A2-B3-C1 is shown, and when n is 3, the segment A3-B1-C2 is shown.
And establishing an equation set through two different frequencies according to the relation between the impedance and the inductance of each section, and calculating the resistance value of each section.
Preferably, in the fourth step, when the resistance of any one section is greater than or equal to 1 Ω or the ratio of two sections exceeds 2, the connection defect of the cable cross-connection grounding system is determined.
In an ideal state, each of the three sections of the cable cross-connection grounding system has no resistance, but in reality, the lengths of the cables are not strictly equal, so that one resistance exists in each section, but the resistance is small, if the resistance is greater than or equal to 1 Ω or the ratio of two to two exceeds 2, an open circuit may exist in the cable, and at this time, the connection defect of the cable cross-connection grounding system is determined.
In the second step, the positive direction of the test current is selected as the direction of the side of the grounding box closest to or farthest from the test current.
As shown in fig. 4 to 6, the present invention further includes a cable cross connect system connection status testing apparatus, including:
the input module is used for respectively coupling A, B, C same-axis cables of the cable cross-connection system with input signals with different frequencies and testing input voltage and input current;
and the output module is used for coupling induction to A, B, C coaxial cables of the cable cross-connection system at the same time and outputting A, B, C current signals responded in the coaxial cables.
Through the arrangement of the input module and the output module, signals with different frequencies are coupled and input, the input voltage and the input current are tested, the cable is coupled and induced, and the current signal responding to the coaxial cable is output.
In this embodiment, the input module includes:
the system comprises a variable frequency power supply, signal injection equipment, input voltage test equipment and input current test equipment which are electrically connected, wherein the variable frequency power supply provides the variable frequency power supply for the signal injection equipment;
the output module includes: the device comprises three coupling sensors and output current testing equipment, wherein the three coupling sensors are respectively sleeved at different sections of a cable cross interconnection system and respectively perform coupling induction, and the output current testing equipment tests response currents in the different sections through the coupling sensors.
The method comprises the steps that a variable frequency power supply, a signal injection device, an input voltage testing device and an input current testing device are arranged, so that the variable frequency power supply is provided, and the input voltage and the input current are detected; through setting up coupling sensor and output current test equipment, test response current in the different sections, easy operation, convenient to use.
Preferably, the input voltage testing device and the input current testing device are alternating current measuring devices, the accuracy is not lower than 0.2 level, and the accuracy of the output current testing device is not lower than 0.5 level.
By setting the precision levels of the input voltage testing equipment, the input current testing equipment and the output current testing equipment, the precision degree of the detected data is ensured, and the reliability of the detection is ensured.
I. Under the condition that coupling injection distinguishes stable signals under power frequency or field interference, the current of the internal interconnection lead of the coaxial cable is as follows:
i is the test frequency category and j is the number of tests, such as IA _ B _ F11, which represents the test data of the 1 st time of the A _ B lead of the cross-connect system at the frequency of F1.
Combining the interconnection lead current obtained by the step I, and establishing a simultaneous equation by applying Faraday's law of electromagnetic induction and applying kirchhoff and ohm's law as follows:
wherein the content of the first and second substances,
| Uij＝k1*Fi*I_Fij | (4) |
i _ Fij is the effective value of the output current of the testing variable frequency power supply, I is the testing frequency category, j is the testing frequency, and k is the proportionality coefficient.
Zn — F is the impedance at different sections and frequencies of the cross-connect grounding system, where n represents different sections of the cross-connect grounding system, i represents the category of the frequency, and when n is 1, represents the impedance of the section a 1-B2-C3; n-2 represents the impedance of the section A2-B3-C1 of the cross-interconnected grounding system; and n-3 represents the impedance of the section A3-B1-C2 of the cross-interconnected grounding system. For example: z1_ F1, representing the impedance of the cross-connect grounding system A1-B2-C3 segment at the F1 frequency.
Solving the solution (2) to obtain Z1_ F1, Z2_ F1 and Z3_ F1;
solution (3) was performed to find Z1_ F2, Z2_ F2, and Z3_ F2.
III: according to the characteristic that the resistance and inductance parameters are independent of the frequency, the following equation is established:
and calculating a resistance Z1_ R and an inductance Z1_ L of a Z1 segment which is a segment A1-B2-C3 of the cross-interconnected grounding system. The same principle is that:
solving a cross-interconnected grounding system A2-B3-C1 section, namely a Z2 section of resistance Z2_ R and inductance Z2_ L;
and a cross-interconnected grounding system A3-B1-C2 segment, namely a Z3 segment, namely a resistor Z3_ R and an inductor Z3_ L.
Examples are as follows:
the data for the injection and testing of coaxial cables in the first set of cross-connect boxes on the cable is given in the following table:
TABLE 1 coaxial Cable injection F1 frequency Signal parameters and test parameters
TABLE 2 coaxial Cable injection F2 frequency Signal parameters and test parameters
Substituting IA _ F11, IB _ F11 and IC _ F11 into formula (1) to obtain:
IA_B_F11＝-4.28A、IB_C_F11＝0.81A、IC_A_F11＝3.47A。
similarly, IA _ B _ F12, IB _ C _ F12, IC _ a _ F12, IA _ B _ F13, IB _ C _ F13, IC _ a _ F13, IA _ B _ F21, IB _ C _ F21, IC _ a _ F21, IA _ B _ F22, IB _ C _ F22, IC _ a _ F22, IA _ B _ F23, IB _ C _ F23, and IC _ a _ F23, and the following table is summarized:
TABLE 3 coaxial Cable lead-in Current parameters
Substituting k with 1.579, F1 and I _ F11 into equation (4) to obtain:
UF11＝1.579*500*5＝7895.7mV
similarly, UF12 and UF13 are 7895.7mV, and UF21, UF22 and UF23 are 5684.9 mV.
In summary, the data in table 1 are substituted into equations (3) and (4) to calculate Z1_ F1, Z2_ F1, Z3_ F1, Z1_ F1, Z2_ F1 and Z3_ F1, as shown in table 4. Z1, Z2 and Z3 represent impedances of sections A1-B2-C3, A2-B3-C1 and A3-B1-C2 of the cable cross-connection grounding system respectively.
TABLE 4 Cross-connect System impedance calculation
Substituting Z11 and Z12 into formula (5) to obtain
Z1_R＝1050mΩ；
Z1_L＝0.935mH；
The same principle is that:
Z2_R＝168.4mΩ，Z2_L＝0.951mH；Z3_R＝152.1mΩ，Z3_L＝0.948mH。
when the resistance of the Z1 section of the cable cross-connection grounding system, namely the A1-B2-C3 section, is more than or equal to 1 omega, and the ratio of the resistance of the Z1 section to the resistance of the two phases of the Z8925 section exceeds 2, the connection defect of the cable cross-connection grounding system is judged.
It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A method for testing the connection state of a cable cross-connection system is characterized by comprising the following steps:
the method comprises the following steps: selecting two signals with frequencies different from power frequency or field interference frequency, wherein the frequencies are respectively F1 and F2, coupling the two signals into A, B, C same-axis cables of a cable cross interconnection system respectively in sequence, and testing the voltage and current values input each time;
step two: when signals are input every time, current signals responding to the same axial cable are coupled and induced A, B, C, and the current value of the lead of the coaxial cable is calculated through the characteristic that the current vector is unchanged;
step three: calculating impedance values of three sections of the cross interconnection system according to the input voltage value and the calculated coaxial cable lead current value, and calculating resistance values of the three sections of the cross interconnection system according to the relationship between the impedance and the resistance and the inductance;
step four: and judging the connection state of the cable cross interconnection system according to the resistance value of each section or the ratio of any two sections of resistance values.
2. The method for testing the connection status of the cable cross-connection system according to claim 1, wherein in the second step, the current value of the coaxial cable lead is calculated by using the following formula:
wherein i is a test frequency category, j is a test frequency, IA _ Fij, IB _ Fij and IC _ Fij are currents responded in A, B, C three-phase coaxial cables when Fi signals are injected in a coupling mode, and IA _ B _ Fij, IB _ C _ Fij and IC _ A _ Fij are lead currents A-B, B-C, C-A in the coaxial cables respectively;
when i is set to 1, injecting an F1 frequency signal; when i is 2, injecting an F2 frequency signal;
when j is set to 1, a signal is injected into the phase A in a coupling mode; when j is 2, coupling and injecting signals into the phase B; when j is 3, a signal is injected to the C phase.
3. The method for testing the connection status of the cable cross-connection system according to claim 2, wherein in the third step, the impedance value of each section of the cross-connection system is calculated by using the following formula:
obtained from Uij Fi I Fij:
-IA_B_Fi1*Z1_Fi+IC_A_Fi1*Z3_Fi＝2*UFi1
-IA_B_Fi2*Z1_Fi+IB_C_Fi2*Z2_Fi＝2*UFi2
-IB_C_Fi3*Z2_Fi+IC_A_Fi3*Z3_Fi＝2*UFi3
wherein Uij is an input voltage effective value, I _ Fij is an input current effective value, and k is a proportionality coefficient;
z1_ Fi, Z2_ Fi and Z3_ Fi respectively represent impedances of different sections when a signal with Fi frequency is injected, Z1 is impedance of sections A1-B2-C3 of the cross interconnection system, Z2 is impedance of sections A2-B3-C1 of the cross interconnection system, and Z3 is impedance of sections A3-B1-C2 of the cross interconnection system;
UFi1, UFi2, and UFi3 are voltage values input when signals are coupled and injected to the a phase, the B phase, and the C phase, respectively.
4. The method for testing the connection state of the cable cross-connection system according to claim 3, wherein in the third step, the following formula is used to calculate the resistance values of the three sections of the cross-connection system:
Zn_F1^2＝Zn_Rn^2+(2*π*F1)^2*Zn_Ln^2
Zn_F2^2＝Zn_Rn^2+(2*π*F2)^2*Zn_Ln^2
wherein Zn _ F1 and Zn _ F2 represent impedances of different segments at frequencies F1 and F2, respectively;
zn _ Rn represents the resistance at different segments, Zn _ Ln represents the inductance at different segments;
n is 1, 2 or 3, and represents A1-B2-C3 when n is 1; when n is 2, the segment A2-B3-C1 is shown, and when n is 3, the segment A3-B1-C2 is shown.
5. The method for testing the connection status of the cable cross-connection grounding system according to claim 1, wherein in the fourth step, when the resistance of any section is greater than or equal to 1 Ω or the ratio of each section exceeds 2, the connection fault of the cable cross-connection grounding system is determined.
6. The method for testing the connection state of the cable cross-connection system according to claim 1, wherein in the second step, the positive direction of the test current is selected to be the direction of the side of the grounding box closest to or farthest from the testing current.
7. A cable cross-connection system connection state testing device is characterized by comprising:
the input module is used for respectively coupling and inputting signals with different frequencies to cables with the same axis A, B, C of the cable cross interconnection system and testing input voltage and input current;
an output module that simultaneously couples the induction to A, B, C coax cables of the cross-cable interconnect system and outputs A, B, C current signals in response in the coax cables.
8. The apparatus for testing connection status of a cable cross-connect system according to claim 7, wherein the input module comprises:
the system comprises a variable frequency power supply, signal injection equipment, input voltage test equipment and input current test equipment which are electrically connected, wherein the variable frequency power supply provides the variable frequency power supply for the signal injection equipment;
the output module includes: the device comprises three coupling sensors and output current testing equipment, wherein the three coupling sensors are respectively sleeved at different sections of a cable cross interconnection system and respectively perform coupling induction, and the output current testing equipment tests response currents in the different sections through the coupling sensors.
9. The apparatus for testing connection status of cable cross-connect system according to claim 8, wherein said input voltage testing device and said input current testing device are ac measuring devices with accuracy not less than 0.2 level.
10. The apparatus for testing connection status of cable cross-connect system according to claim 8, wherein the accuracy of the output current testing equipment is not less than 0.5 level.
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