Fault detection device and detection method for cable branch box

Abstract

The invention relates to a fault detection device and method for a cable branch box, and the device and method are used for the fault detection of the cable branch box, and a fault detection module carries out the fault detection according to data sampling. The fault detection module judges whether the loop is fused at present, and if the loop is fused and the loop is over-current, the fault reason is the loop over-current; or if the loop is fused, no loop overcurrent exists and the loop is short-circuited, the fault is short-circuited; or if the loop is fused, no loop overcurrent exists and no loop short circuit exists, the fault reason is the fuse fault; the detection method is used for the detection device. According to the invention, the fault position and type are determined according to whether loop fusing, loop overcurrent and loop short circuit occur in sequence, and display and warning are carried out through the man-machine interaction module, so that the fault position of the cable branch box can be conveniently found out, and maintenance personnel can conveniently and rapidly position and maintain the fault.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical fault detection devices, and in particular to a fault detection device and a detection method for a cable branch box. Background Art

[0002] In the operation of the distribution network, power outages of the outgoing line circuits of the 0.4kV cable branch box often occur. Under such working conditions, it is difficult to judge from the appearance which outgoing line circuit of the cable branch box fuse is blown, and it is also impossible to determine whether the fuse-blowing power outage is caused by overcurrent or short circuit. Such faults are very difficult to judge whether the cause of the power outage is a line problem or a load problem. The frequent occurrence of such events has greatly increased the work pressure of the power grid operation and maintenance personnel. Failure to timely analyze and find the cause of the fault will also cause a decrease in user satisfaction, thereby affecting the image of the power supply company.

[0003] The invention patent with publication number CN104578429A discloses an online operation monitoring system for a cable branch box, including a measurement and analysis module, a voltage acquisition module, a current acquisition module, a temperature acquisition module, a communication module, a display module, an audible and visual alarm module, a corona flashover detection module, a remote portable terminal, a central network server, etc. The system measures the current, voltage, temperature, and even the flashover of the electrical equipment in the cable branch box in real time, performs real-time calculation, analysis, and judgment, and performs local or remote early warning and alarm after abnormalities or faults are found; the patent realizes the real-time online automatic monitoring and alarm of the cable branch box, but does not realize the location of the fuse fault of a certain phase circuit, and cannot identify the cause of the fault.

[0004] Therefore, providing a detection device that can realize fault location is an issue that urgently needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a fault detection device and a detection method for a cable branch box in order to overcome the defects of the above-mentioned prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, there is provided a fault detection device for a cable branch box, which is used for detecting a fault of the cable branch box. The cable branch box comprises a fuse, a power supply side and a load side, wherein the power supply side and the load side are respectively connected to the fuse. The device comprises a fault detection module and a data sampling module, wherein the fault detection module is connected to the data sampling module, wherein the data sampling module is respectively connected to the power supply side and the load side for data sampling, and wherein the fault detection module performs fault detection according to the data sampling.

[0008] The fault detection module determines whether the circuit is currently blown. If the circuit is blown and the circuit is overcurrent, the fault cause is the circuit overcurrent; or if the circuit is blown, there is no circuit overcurrent and the circuit is short-circuited, the fault cause is the circuit short-circuit; or if the circuit is blown, there is no circuit overcurrent and there is no circuit short-circuit, the fault cause is a fuse failure.

[0009] As a preferred technical solution, the data sampling module includes a voltage sensor and a current sensor, the voltage sensor is connected to the power supply side, and the current sensor is connected to the load side.

[0010] As a preferred technical solution, the device also includes a human-computer interaction module, a parameter management module and a communication management module. The parameter management module is respectively connected to the human-computer interaction module and the fault detection module. The parameters of the parameter management module are set through the human-computer interaction module. The fault detection module performs fault detection according to the set parameters and data sampling. The communication management module is connected to the fault detection module, and the communication management module transmits the detection results to the human-computer interaction module or uploads them wirelessly.

[0011] According to another aspect of the present invention, there is provided a detection method for a fault detection device of any of the above cable branch boxes, the method comprising the following steps:

[0012] S1, the fault detection module reads the voltage effective value, current effective value and current instantaneous value of the three phases, and performs data sampling by real-time scanning;

[0013] S2, the fault detection module determines whether the circuit is blown, and if so, determines whether the circuit is overcurrent;

[0014] S3. If the circuit is not overcurrent, determine whether the circuit is short-circuited;

[0015] S4. If the circuit is not short-circuited, the fuse is faulty, and the fault location and type are recorded and a warning is issued through the human-computer interaction module.

[0016] As a preferred technical solution, the step S2 specifically further includes:

[0017] S21. If the circuit is not blown, real-time scanning is performed to sample data.

[0018] As a preferred technical solution, the step S3 specifically further includes:

[0019] S31. If the circuit is overcurrent, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

[0020] As a preferred technical solution, the step S4 specifically further includes:

[0021] S41. If the circuit is short-circuited, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

[0022] As a preferred technical solution, the judgment process of the circuit fusing is as follows:

[0023] In Tn1, the effective values ​​of the voltages of the three phases are taken as the first average value, and the effective values ​​of the currents of the three phases are taken as the second average value. If the first average value is greater than UN*0.85 and the second average value changes from greater than Icri1 to 0, the circuit is blown;

[0024] Among them, Tn1 is the preset time, UN is the rated voltage, and Icri1 is the minimum load current threshold.

[0025] As a preferred technical solution, the circuit overcurrent judgment process is:

[0026] In Tn2 before the fuse is blown, the effective values ​​of the currents of the three phases are taken as the third average value. If the third average value is greater than Icri2, the circuit is overcurrent;

[0027] Among them, Tn2 is the preset time, and Icri2 is the rated current value of the fuse.

[0028] As a preferred technical solution, the process of determining whether the circuit is short-circuited is as follows:

[0029] In Tn3 before the fuse is blown, the instantaneous current values ​​of the three phases take the maximum value. If the maximum value is greater than Icri3, the circuit is short-circuited;

[0030] Among them, Tn3 is the preset time, and Icri3 is the short-circuit current constant.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention determines the fault location and type by checking whether circuit fusing, circuit overcurrent and circuit short circuit occur in turn, and displays and warns through a human-computer interaction module, so as to facilitate the identification of the fault location of the cable branch box and facilitate maintenance personnel to quickly locate the fault and repair it.

[0033] 2. The present invention determines whether a circuit is blown, a circuit is overcurrented, or a circuit is short-circuited by setting corresponding conditions, and the result of determining the circuit status is relatively accurate.

[0034] 3. The present invention sets corresponding parameters through the parameter management module, and changes the judgment conditions of circuit fusing, circuit overcurrent and circuit short circuit by adjusting the parameters, so as to facilitate corresponding adjustments according to actual conditions.

[0035] 4. The present invention samples the voltage and current respectively by setting a voltage sensor and a current sensor, and transmits the data to the fault detection module; setting a plurality of current sensors and voltage sensors can complete the detection of a plurality of loops at the same time.

[0036] 5. The present invention is provided with a communication management module to transmit the detection results to the human-computer interaction module, and can also transmit the detection results to a remote monitoring platform by using a wireless network. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0038] Figure 2 It is a connection schematic diagram of the present invention;

[0039] Figure 3 The figure is a schematic diagram of the fault judgment process flow of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] In the operation of the distribution network, power outages of the outgoing line circuits of the 0.4kV cable branch box often occur. Under such working conditions, it is difficult to judge from the appearance which outgoing line circuit of the cable branch box fuse is blown, and it is also impossible to determine whether the fuse-blowing power outage is caused by overcurrent or short circuit. Such faults are very difficult to judge whether the cause of the power outage is a line problem or a load problem. The frequent occurrence of such events has greatly increased the work pressure of the power grid operation and maintenance personnel. Failure to timely analyze and find the cause of the fault will also cause a decrease in user satisfaction, thereby affecting the image of the power supply company.

[0042] The existing power quality monitors and load recorders on the market have certain operation monitoring and analysis capabilities, but generally only support single-circuit monitoring and cannot simultaneously collect information on multiple outgoing line circuits of the cable branch box. Moreover, such equipment generally requires manual export of measurement and recording data for analysis, which is costly and inconvenient to install and use.

[0043] The present invention provides a fault detection device and method for a cable branch box. The present invention determines the fault location and type by checking whether a circuit is blown, circuit is overcurrented, and circuit is short-circuited in sequence, and displays and warns through a human-computer interaction module, so as to facilitate the identification of the fault location of the cable branch box and facilitate maintenance personnel to quickly locate the fault and repair it. The present invention sets corresponding conditions to determine whether a circuit is blown, circuit is overcurrented, and circuit is short-circuited, and the result of judging the circuit state is relatively accurate. The present invention sets corresponding parameters through a parameter management module, and changes the judgment conditions of circuit blown, circuit overcurrent, and circuit short-circuited by adjusting the parameters, so as to facilitate corresponding adjustments according to actual conditions. The present invention samples the voltage and current respectively by setting a voltage sensor and a current sensor, and transmits the data to the fault detection module; setting multiple current sensors and voltage sensors can complete the detection of multiple circuits at the same time. The present invention sets a communication management module to transmit the detection results to a human-computer interaction module, and can also transmit the detection results to a remote monitoring platform by using a wireless network.

[0044] Example 1

[0045] A fault detection device for a cable branch box, used for detecting faults of the cable branch box, the cable branch box comprising a fuse, a power supply side and a load side, the power supply side and the load side being connected to the fuse respectively, the device comprising a fault detection module and a data sampling module, the fault detection module being connected to the data sampling module, the data sampling module being connected to the power supply side and the load side respectively for data sampling, and the fault detection module performing fault detection according to the data sampling;

[0046] The fault detection module determines whether the circuit is currently blown. If the circuit is blown and the circuit is overcurrent, the fault cause is the circuit overcurrent; or if the circuit is blown, there is no circuit overcurrent and the circuit is short-circuited, the fault cause is the circuit short-circuit; or if the circuit is blown, there is no circuit overcurrent and there is no circuit short-circuit, the fault cause is a fuse failure.

[0047] The data sampling module includes a voltage sensor and a current sensor, the voltage sensor is connected to the power supply side, and the current sensor is connected to the load side. The device also includes a human-computer interaction module, a parameter management module and a communication management module, the parameter management module is connected to the human-computer interaction module and the fault detection module respectively, the human-computer interaction module is used to set parameters for the parameter management module, the fault detection module performs fault detection according to the set parameters and data sampling, the communication management module is connected to the fault detection module, and the communication management module transmits the detection result to the human-computer interaction module or uploads it wirelessly.

[0048] In this embodiment, if Figure 1 and Figure 2As shown, the cable branch box is a 0.4kv cable branch box, the incoming line side (upper part) is called the power side, and the outgoing line side (lower part) is called the load side. The detection device accesses the three-phase AC voltage signal and the neutral line voltage signal at the power input end of the cable branch box to be tested through the voltage sensor on the power side as the voltage sampling input of the detection device, and also uses any phase live wire (such as phase A) and the neutral line (N line) to provide working power for the detection device. The detection device accesses the load side current signals of multiple outgoing line circuits of the cable branch box to be tested through the current sensor, and each current sensor sampling circuit corresponds to an outgoing line circuit. The detection device makes a fault detection logic algorithm judgment based on the various input AC signal quantities and the preset equipment parameters, judges the cause of the fault when the outgoing line circuit or the fuse is blown and the power is cut off, and provides a human-machine interface indication.

[0049] The detection device includes a human-computer interaction module, a parameter management module, a fault detection module, a data sampling module, and a communication management module; the human-computer interaction module includes a human-computer interaction interface, which is used to display fault information and set parameters for the parameter management module; the parameter management module includes a parameter setting unit and a fixed value parameter unit, which set different types of parameters; the fault detection module includes a detection result unit and a fault detection unit, the fault detection unit detects the sampling data of the data sampling module, and the detection structure unit outputs the detection result; the data sampling module includes a voltage sampling unit and a current sampling unit, the voltage sampling unit is connected to the voltage sensor, and the current sampling unit is connected to the current sensor; the communication management module performs wireless network transmission through 4G Cat.1.

[0050] Example 2

[0051] like Figure 3 As shown, a detection method for a fault detection device of a cable branch box, the method comprising the following steps:

[0052] S1, the fault detection module reads the voltage effective value, current effective value and current instantaneous value of the three phases, and performs data sampling by real-time scanning;

[0053] S2, the fault detection module determines whether the circuit is blown, and if so, determines whether the circuit is overcurrent;

[0054] S3. If the circuit is not overcurrent, determine whether the circuit is short-circuited;

[0055] S4. If the circuit is not short-circuited, the fuse is faulty, and the fault location and type are recorded and a warning is issued through the human-computer interaction module.

[0056] The step S2 specifically also includes:

[0057] S21. If the circuit is not blown, real-time scanning is performed to sample data.

[0058] The step S3 specifically includes:

[0059] S31. If the circuit is overcurrent, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

[0060] The step S4 specifically also includes:

[0061] S41. If the circuit is short-circuited, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

[0062] The judgment process of the circuit fuse is as follows: within Tn1, the effective values ​​of the voltages of the three phases take the first average value, and the effective values ​​of the currents of the three phases take the second average value. If the first average value is greater than UN*0.85 and the second average value changes from greater than Icri1 to 0, the circuit is blown; wherein Tn1 is the preset time, UN is the rated voltage, and Icri1 is the minimum load current threshold value.

[0063] The judgment process of the circuit overcurrent is as follows: within Tn2 before the fuse is blown, the effective values ​​of the currents of the three phases take the third average value. If the third average value is greater than Icri2, the circuit is overcurrent; wherein Tn2 is the preset time, and Icri2 is the rated current value of the fuse.

[0064] The judgment process of the circuit short circuit is as follows: within Tn3 before the fuse is blown, the instantaneous current values ​​of the three phases take the maximum value. If the maximum value is greater than Icri3, the circuit is short-circuited; wherein Tn3 is the preset time, and Icri3 is the short-circuit current constant.

[0065] In this embodiment, the fault location and type are determined by sequentially judging whether the circuit is blown, the circuit is overcurrented, and the circuit is short-circuited.

[0066] Circuit fuse criterion: within Tn1, the mean of the effective values ​​of the three phase voltages on the power supply side is >UN*0.85, and the mean of the effective current changes from >Icri1 to 0; Icri1 is the minimum load current threshold set by the user for line operation; Tn1 can be set, and the default is 10 seconds. Specifically, UN can generally be 230V for phase voltage, Tn1 is 10s, Icri1 is manually set, Icri1 is 1A, the mean of the effective voltage value (i.e. the first average value) within 10 seconds is >230*0.85, and the mean of the effective current value (i.e. the second average value) changes from >1A to 0; the calculation period of the effective value mean of voltage and current is 20ms, that is, one effective value is calculated per cycle.

[0067] Circuit overcurrent criterion: within Tn2, the mean of the effective current values ​​of the three phases (i.e. the third average value)>Icri2; Icri2 is the rated current setting of the fuse set by the user; Tn2 can be set, the default is 60 seconds, i.e. Tn2 is 60 seconds. The rated current of the fuse is 100A, and within the first 60 seconds, the mean of the effective current values ​​of the three phases (i.e. the third average value)>100.

[0068] Loop short circuit criterion: within Tn3, the maximum instantaneous current value of the three phases>Icri3; Icri3 is the short-circuit current constant set by the user; Tn3 can be set, the default is 10 milliseconds, that is, Tn3 is 10 milliseconds; the rated current of the fuse is 100A, and within the first 10 milliseconds, the maximum instantaneous current value>600A.

[0069] The short-circuit current setting value is much larger than the rated current. For example, if the rated current of the fuse is 100A, the short-circuit current setting value can be set to 600A.

[0070] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A fault detection device for a cable branch box, used for detecting a fault of a cable branch box, wherein the cable branch box comprises a fuse, a power supply side and a load side, wherein the power supply side and the load side are respectively connected to the fuse, wherein the device comprises a fault detection module and a data sampling module, wherein the fault detection module and the data sampling module are connected, and wherein: The data sampling module is respectively connected to the power supply side and the load side to perform data sampling, and the fault detection module performs fault detection according to the data sampling; The fault detection module determines whether the circuit is currently blown. If the circuit is blown and the circuit is overcurrent, the fault cause is the circuit overcurrent; or if the circuit is blown, there is no circuit overcurrent and the circuit is short-circuited, the fault cause is the circuit short-circuit; or if the circuit is blown, there is no circuit overcurrent and there is no circuit short-circuit, the fault cause is a fuse failure.

2. A cable branch box fault detection device according to claim 1, characterized in that: The data sampling module includes a voltage sensor and a current sensor. The voltage sensor is connected to the power supply side, and the current sensor is connected to the load side.

3. A cable branch box fault detection device according to claim 1, characterized in that: The device also includes a human-computer interaction module, a parameter management module and a communication management module. The parameter management module is connected to the human-computer interaction module and the fault detection module respectively. The parameters of the parameter management module are set through the human-computer interaction module. The fault detection module performs fault detection according to the set parameters and data sampling. The communication management module is connected to the fault detection module, and the communication management module transmits the detection result to the human-computer interaction module or uploads it wirelessly.

4. A detection method for a fault detection device of a cable branch box according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1, the fault detection module reads the voltage effective value, current effective value and current instantaneous value of the three phases, and performs data sampling by real-time scanning; S2, the fault detection module determines whether the circuit is blown, and if so, determines whether the circuit is overcurrent; S3. If the circuit is not overcurrent, determine whether the circuit is short-circuited; S4. If the circuit is not short-circuited, the fuse is faulty, and the fault location and type are recorded and a warning is issued through the human-computer interaction module.

5. The detection method according to claim 4, characterized in that: The step S2 specifically also includes: S21. If the circuit is not blown, real-time scanning is performed to sample data.

6. The detection method according to claim 4, characterized in that: The step S3 specifically includes: S31. If the circuit is overcurrent, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

7. The detection method according to claim 4, characterized in that: The step S4 specifically also includes: S41. If the circuit is short-circuited, the fault location and fault type are recorded and a warning is issued through the human-computer interaction module.

8. The detection method according to claim 4, characterized in that: The judgment process of the circuit fusing is as follows: In Tn1, the effective values ​​of the voltages of the three phases are taken as the first average value, and the effective values ​​of the currents of the three phases are taken as the second average value. If the first average value is greater than UN*0.85 and the second average value changes from greater than Icri1 to 0, the circuit is blown; Among them, Tn1 is the preset time, UN is the rated voltage, and Icri1 is the minimum load current threshold.

9. The detection method according to claim 4, characterized in that: The judgment process of the circuit overcurrent is as follows: In Tn2 before the fuse is blown, the effective values ​​of the currents of the three phases are taken as the third average value. If the third average value is greater than Icri2, the circuit is overcurrent; Among them, Tn2 is the preset time, and Icri2 is the rated current value of the fuse.

10. The detection method according to claim 4, characterized in that: The judgment process of the loop short circuit is as follows: In Tn3 before the fuse is blown, the instantaneous current values ​​of the three phases take the maximum value. If the maximum value is greater than Icri3, the circuit is short-circuited; Among them, Tn3 is the preset time, and Icri3 is the short-circuit current constant.

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