Automatic feeder detection system

Abstract

The invention discloses an automatic feeder detection system which comprises a power distribution network equivalent model construction unit, a fault feature analysis unit, a real-time data acquisition unit, a real-time data transmission unit, a fault identification unit, a fault positioning unit, a result output unit, an automatic feeder isolation unit and a power supply recovery unit. The power distribution network equivalent model construction unit is used for constructing an equivalent model, the fault feature analysis unit analyzes fault types and features, the real-time data acquisition unit acquires real-time data, the real-time data transmission unit transmits the data to the fault identification unit, and the fault identification unit detects faults. The fault positioning unit determines the position of a fault point, the result output unit outputs a result, the automatic feeder isolation unit takes isolation measures for the fault, and the power supply recovery unit performs power supply recovery; faults can be quickly found and positioned, the fault positions are timely isolated, power supply is recovered, the safety and stability of the power distribution network are improved, and the operation quality of the power distribution network is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of feeder automation, and in particular relates to a feeder automation detection system. Background Art

[0002] Feeder is a cable line, which mainly plays the role of power transmission. The quality of feeder directly determines the operation quality of smart distribution network. Feeder automation refers to the automation of feeder line from substation to user's power equipment, including user detection, data measurement and operation optimization under normal circumstances, as well as fault detection, fault isolation, transfer and power supply restoration control under accident conditions. The existing feeder automation detection technology has problems such as feeder fault location detection error, slow isolation and power supply restoration, which affects the safe and stable operation of distribution network and reduces the power supply quality of distribution network.

[0003] Therefore, in order to solve the above problems, it is necessary to develop a feeder automatic detection system. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a feeder automation detection system to quickly discover and locate faults, isolate the fault location in time and restore power supply, improve the safety and stability of the distribution network, and ensure the operation quality of the distribution network.

[0005] The object of the present invention is achieved as follows: A feeder automation detection system includes a distribution network equivalent model building unit, a fault feature analysis unit, a real-time data acquisition unit, a real-time data transmission unit, a fault identification unit, a fault location unit, a result output unit, an automated feeder isolation unit and a power supply restoration unit;

[0006] The distribution network equivalent model construction unit is used to construct a corresponding equivalent model according to the spatial structure and component elements of the distribution network. The fault characteristic analysis unit performs a specific analysis on the fault type and characteristics of the distribution network based on the constructed distribution network equivalent model, and uses the characteristic analysis results of the fault as a comparison standard for feeder detection.

[0007] The real-time data acquisition unit is used to collect real-time data through a data acquisition device installed on the distribution network feeder, detect and obtain real-time distribution network feeder operation data, read and count the data through the real-time data transmission unit, and transmit it to the fault identification unit;

[0008] The fault identification unit detects the feeder operation status and faults based on the collected feeder operation data by using the ratio method of the feeder positive voltage rise time and fall time. After the ratio is obtained, it is compared with the characteristic analysis result of the fault. When the fault is detected, the position between the fault point and the center of the distribution network feeder is determined by the fault location unit, and the fault location detection result is output by the result output unit.

[0009] Based on the fault location detection results, the automatic feeder isolation unit takes corresponding isolation measures for faults in different locations to separate the fault area from the non-fault area, and the power supply is restored according to the fault type through the power supply restoration unit.

[0010] Furthermore, in the distribution network equivalent model construction unit, under normal conditions, the operation of the distribution network feeder satisfies the following relationship:

[0011] ,

[0012] Where L is the length of the feeder, U is the voltage value of the distribution network, n is the number of feeder lines, R1 and R3 are the resistance values ​​of the feeder line resistance and the resistor on the distribution network respectively, and t is the continuous operation time of the feeder.

[0013] Furthermore, the fault types in the fault feature analysis unit include feeder grounding fault and metallic grounding fault.

[0014] Furthermore, the data acquisition equipment in the real-time data acquisition unit includes a current detection device, a voltage detection device, a directional coupler, an oscilloscope and a PC.

[0015] Furthermore, the directional coupler is connected to the power distribution network feeder in a reverse form to sample the incident signal and the reflected signal respectively.

[0016] Furthermore, the fault identification unit adopts the ratio method of the rise time and fall time of the positive pole voltage of the feeder to realize the detection of the feeder operation status and fault, specifically including setting the time during which the positive pole voltage of the line falls within the first traveling wave time after the fault as t d The time it takes for the voltage to rise is t r , then the ratio of voltage rise and fall time is:

[0017] ,

[0018] Combining the characteristics of different fault types in the distribution network as the basis for detecting faulty feeders and non-faulty feeders, the detection criterion is quantified as

[0019] k t >k set ,

[0020] In the formula, k set is the detection threshold, and its specific value is determined by the operating characteristics of the fault type.

[0021] Furthermore, the distance between the fault point in the fault location unit and the center of the distribution network feeder is specifically expressed as:

[0022] The distance x between the fault point and the detection point at the left end of the cable is expressed as:

[0023] ,

[0024] In the formula, xfault and xcore are the coordinates of the fault point and the center point of the feeder in the x direction, v is the transmission speed of the signal, Δt is the time difference between the arrival of the fault traveling wave at both ends, and the relationship between Δt and the fault point is:

[0025] ,

[0026] In the formula, t1 and t2 are the times when the initial fault signal is detected by the measuring points at both ends, and the expression is:

[0027] ,

[0028] Where, t a ,t b are the time difference between the feeder fault signal detected at the left end of the cable and the zero-crossing point of the voltage waveform at the left and right ends, t x t0 and t1 are the time difference between the first voltage zero crossing point of the feeder and the voltage zero crossing points at both ends of the feeder.

[0029] Furthermore, the automated feeder isolation unit takes corresponding isolation measures for faults at different locations, specifically, when a fault occurs at the feeder power switch position, the power switch and all its adjacent switches are controlled to trip, and the power switch reclosing function is turned off; when a fault occurs in the station outgoing line section, the switch is immediately tripped, and its corresponding switch control device is kept in an open state, and the fault current information is also sent to the adjacent switch control device to control the corresponding switch to disconnect and isolate the fault; when a fault occurs on the main line, the fault current information is transmitted to the upper-level switch control device through the switch, and the switch control device receives the information and controls the main line switch to disconnect and isolate the fault.

[0030] Furthermore, the power supply recovery unit performs power supply recovery according to the fault type, specifically including power supply recovery for transient faults and power supply recovery for permanent faults.

[0031] Due to the adoption of the above technical scheme, the beneficial effects of the present invention are as follows: by constructing an equivalent model of the smart distribution network in the urban core area according to the spatial structure and component elements of the feeder, and conducting a specific analysis of the fault types and characteristics of the distribution network, taking the characteristic analysis results of the fault as the comparison standard for feeder detection, real-time collection of distribution network feeder operation data, based on the real-time collection data and the characteristic analysis results of the fault, the feeder operation status and fault are detected, and the fault point is quickly located, and isolation treatment is taken for the fault area, and power supply to other non-fault locations in the same distribution network is quickly restored, thereby improving the detection efficiency and the safety and stability performance of the distribution network, and ensuring the operation quality of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural block diagram of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, a feeder automation detection system includes a distribution network equivalent model building unit, a fault feature analysis unit, a real-time data acquisition unit, a real-time data transmission unit, a fault identification unit, a fault location unit, a result output unit, an automatic feeder isolation unit and a power supply restoration unit.

[0035] The distribution network equivalent model construction unit is used to construct a corresponding equivalent model according to the spatial structure and component elements of the distribution network. Preferably, in the distribution network equivalent model construction unit, under normal conditions, the operation of the distribution network feeder satisfies the following relationship:

[0036] ,

[0037] Where L is the length of the feeder, U is the voltage value of the distribution network, n is the number of feeder lines, R1 and R3 are the resistance values ​​of the feeder line resistance and the resistor on the distribution network respectively, and t is the continuous operation time of the feeder.

[0038] The fault characteristic analysis unit specifically analyzes the fault types and characteristics of the distribution network based on the constructed distribution network equivalent model, and uses the fault characteristic analysis results as a comparison standard for feeder detection; preferably, the fault types in the fault characteristic analysis unit include feeder grounding faults, metallic grounding faults and other faults.

[0039] Wherein, the real-time data acquisition unit is used to collect real-time data through a data acquisition device installed on the distribution network feeder, and detect and obtain real-time distribution network feeder operation data. Preferably, the data acquisition device includes a current detection device, a voltage detection device, a directional coupler, an oscilloscope and a PC; the directional coupler is specifically connected to the distribution network feeder in a reverse form, and the incident signal and the reflected signal are sampled respectively; then, the data is read and counted through the real-time data transmission unit, and transmitted to the fault identification unit.

[0040] Wherein, the fault identification unit uses the ratio method of the feeder positive voltage rise time and fall time to detect the feeder operation status and fault based on the collected feeder operation data. After the ratio is obtained, it is compared with the characteristic analysis result of the fault. Preferably, the feeder positive voltage rise time and fall time ratio method is used to detect the feeder operation status and fault, which specifically includes setting the time that the line positive voltage drops within the first traveling wave time after the fault as t d The time it takes for the voltage to rise is t r , then the ratio of voltage rise and fall time is:

[0041] ,

[0042] Combining the characteristics of different fault types in the distribution network as the basis for detecting faulty feeders and non-faulty feeders, the detection criterion is quantified as

[0043] k t >k set ,

[0044] In the formula, k set is the detection threshold, and its specific value is determined by the operating characteristics of the fault type.

[0045] When a fault is detected, the position between the fault point and the center of the distribution network feeder is determined by the fault location unit, and the fault location detection result is output by the result output unit. Preferably, the distance between the fault point and the center of the distribution network feeder in the fault location unit is specifically expressed as:

[0046] The distance x between the fault point and the detection point at the left end of the cable is expressed as:

[0047] ,

[0048] In the formula, x fault 、x core are the coordinates of the fault point and the center point of the feeder in the x direction, v is the transmission speed of the signal, Δt is the time difference between the fault traveling wave and the two ends, and the relationship between Δt and the fault point is:

[0049] ,

[0050] In the formula, t1 and t2 are the times when the initial fault signal is detected by the measuring points at both ends, and the expression is:

[0051] ,

[0052] Where, t a ,t b are the time difference between the feeder fault signal detected at the left end of the cable and the zero-crossing point of the voltage waveform at the left and right ends, t x t0 and t1 are the time difference between the first voltage zero crossing point of the feeder and the voltage zero crossing points at both ends of the feeder.

[0053] Among them, based on the fault location detection result, corresponding isolation measures are taken for faults at different positions through the automated feeder isolation unit to achieve separation of the fault area and the non-fault area. Preferably, it specifically includes that when a fault occurs at the feeder power switch position, the power switch and all adjacent switches are controlled to trip and the power switch reclosing function is turned off; when a fault occurs in the station outgoing line section, the switch is immediately tripped and its corresponding switch control device is kept in an open state, and the fault current information is also sent to the adjacent switch control device to control the corresponding switch to disconnect and isolate the fault; when a fault occurs on the main line, the fault current information is transmitted to the upper-level switch control device through the switch, and the switch control device receives the information and controls the main line switch to disconnect and isolate the fault; and power supply is restored according to the fault type through the power supply recovery unit, preferably, it specifically includes power supply recovery for transient faults and power supply recovery for permanent faults.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A feeder automation detection system, characterized in that: It includes a distribution network equivalent model building unit, a fault feature analysis unit, a real-time data acquisition unit, a real-time data transmission unit, a fault identification unit, a fault location unit, a result output unit, an automatic feeder isolation unit and a power supply restoration unit; The distribution network equivalent model construction unit is used to construct a corresponding equivalent model according to the spatial structure and component elements of the distribution network. The fault characteristic analysis unit performs a specific analysis on the fault type and characteristics of the distribution network based on the constructed distribution network equivalent model, and uses the characteristic analysis results of the fault as a comparison standard for feeder detection. The real-time data acquisition unit is used to collect real-time data through a data acquisition device installed on the distribution network feeder, detect and obtain real-time distribution network feeder operation data, read and count the data through the real-time data transmission unit, and transmit it to the fault identification unit; The fault identification unit detects the feeder operation status and faults based on the collected feeder operation data by using the ratio method of the feeder positive voltage rise time and fall time. After the ratio is obtained, it is compared with the characteristic analysis result of the fault. When the fault is detected, the position between the fault point and the center of the distribution network feeder is determined by the fault location unit, and the fault location detection result is output by the result output unit. Based on the fault location detection results, the automatic feeder isolation unit takes corresponding isolation measures for faults in different locations to separate the fault area from the non-fault area, and the power supply is restored according to the fault type through the power supply restoration unit.

2. A feeder automation detection system according to claim 1, characterized in that: In the distribution network equivalent model construction unit, under normal conditions, the operation of the distribution network feeder satisfies the following relationship: ， Where L is the length of the feeder, U is the voltage value of the distribution network, n is the number of feeder lines, R1 and R3 are the resistance values ​​of the feeder line resistance and the resistor on the distribution network respectively, and t is the continuous operation time of the feeder.

3. A feeder automation detection system according to claim 1, characterized in that: The fault types in the fault feature analysis unit include feeder grounding fault and metallic grounding fault.

4. A feeder automation detection system according to claim 1, characterized in that: The data acquisition equipment in the real-time data acquisition unit includes a current detection device, a voltage detection device, a directional coupler, an oscilloscope and a PC.

5. A feeder automation detection system according to claim 4, characterized in that: The directional coupler is connected to the power distribution network feeder in a reverse form, and samples the incident signal and the reflected signal respectively.

6. A feeder automation detection system according to claim 1, characterized in that: The fault identification unit adopts the ratio method of the rise time and fall time of the positive pole voltage of the feeder to realize the detection of the feeder operation status and fault, specifically including setting the time during which the positive pole voltage of the line falls within the first traveling wave time after the fault as t d The time it takes for the voltage to rise is t r , then the ratio of voltage rise and fall time is: ， Combining the characteristics of different fault types in the distribution network as the basis for detecting faulty feeders and non-faulty feeders, the detection criterion is quantified as k t >k set , In the formula, k set is the detection threshold, and its specific value is determined by the operating characteristics of the fault type.

7. The feeder automation detection system according to claim 1, characterized in that: The distance between the fault point in the fault location unit and the center of the distribution network feeder is specifically expressed as: The distance x between the fault point and the detection point at the left end of the cable is expressed as: ， In the formula, x fault 、x core are the coordinates of the fault point and the center point of the feeder in the x direction, v is the transmission speed of the signal, Δt is the time difference between the fault traveling wave and the two ends, and the relationship between Δt and the fault point is: ， In the formula, t1 and t2 are the times when the initial fault signal is detected by the two end measuring points, respectively. The expression is: ， Where, t a ,t b are the time difference between the feeder fault signal detected at the left end of the cable and the zero-crossing point of the voltage waveform at the left and right ends, t x t0 and t1 are the time difference between the first voltage zero crossing point of the feeder and the voltage zero crossing points at both ends of the feeder.

8. The feeder automation detection system according to claim 1, characterized in that: The automated feeder isolation unit takes corresponding isolation measures for faults at different locations, specifically, when a fault occurs at the feeder power switch location, the power switch and all adjacent switches are controlled to trip and the power switch reclosing function is turned off; when a fault occurs in the station outgoing line section, the switch is immediately tripped and its corresponding switch control device is kept in an open state, while the fault current information is also sent to the adjacent switch control device to control the corresponding switch to disconnect and isolate the fault; when a fault occurs on the main line, the fault current information is transmitted to the upper-level switch control device through the switch, and the switch control device receives the information and controls the main line switch to disconnect and isolate the fault.

9. The feeder automation detection system according to claim 1, characterized in that: The power supply recovery unit performs power supply recovery according to the fault type, specifically including power supply recovery for transient faults and power supply recovery for permanent faults.

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