Traveling wave-based power distribution network line fault positioning system

Abstract

The utility model discloses a power distribution network line fault positioning system based on traveling waves, and belongs to the technical field of power distribution automation. Comprising a traveling wave acquisition sensor, the output end of the traveling wave acquisition sensor is connected with the input end of an analog-to-digital conversion module, the output end of the analog-to-digital conversion module is connected with the input end of a master control module, the master control module is connected with a master station through a communication module, and the input end of the master control module is further connected with a time synchronization module. The crystal oscillator is connected with a clock input pin of the counter circuit through the frequency dividing circuit, the reset signal is connected with a reset pin of the counter circuit, the GPS module is connected with a control signal input end of the latch circuit through the clock interface, the counter circuit is connected with a data signal input end of the latch circuit, and the clock interface is connected with the main control module. According to the invention, the main control module can obtain two time signals with the resolution ratio of 1 microsecond through the time synchronization module, so that the continuous reliability of time synchronization is improved.

Description

TECHNICAL FIELD

[0001] The application discloses a line fault positioning system based on a traveling wave of a power distribution network and belongs to the technical field of power distribution automation. BACKGROUND

[0002] High-voltage line fault tripping is one of common accidents of a power grid, which directly affects system safety, equipment safety and power supply reliability of the power grid, and therefore, when a power transmission line is faulty, it is very important to timely give a pre-warning of the fault and determine the fault position for repairing the power transmission line.

[0003] The existing fault detection methods of the power distribution network are impedance method and traveling wave method. The impedance method assumes that transmission line parameters are the same, and considers that the impedance or the reactance of a fault loop under different fault types is proportional to the distance of a measuring point, and the impedance method has the defects of large fault point distance calculation error and incapability of excluding pseudo faults. The traveling wave method utilizes a time difference of fault traveling waves arriving at two ends of a line to calculate a fault distance, and has high reliability. In the prior art, a common technical means is to arrange a traveling wave collection system in a line, and utilize a GPS module or a Beidou module as a time synchronization module in the traveling wave collection system to obtain GPS absolute time of collected waveforms, such as the technical solutions disclosed in patent documents with publication numbers CN114859176A, CN118518978A, CN215894808U and CN217606005U. However, it is found in actual implementation that only the GPS or Beidou module is utilized as the time synchronization module, and the time synchronization has poor persistence, and errors are prone to occur in the absolute time of the collected waveforms, and therefore, it becomes a problem to be solved in the field to design a technical solution capable of providing time synchronization persistence to ensure accurate acquisition of the absolute time of the collected waveforms. CONTENT OF THE UTILITY MODEL

[0004] The utility model solves the technical problem of overcoming the defects of the prior art and providing a line fault positioning system based on a traveling wave of a power distribution network, and a main control module can obtain two time signals with a resolution of 1 microsecond through a time synchronization module, and therefore, the persistence reliability of time synchronization is improved.

[0005] The utility model solves its technical problem adopts the technical scheme that the technical scheme is: this based on wave of distribution network line fault location system, including wave collection sensor, wave collection sensor's output end connects the input end of analog-digital conversion module, the output end of analog-digital conversion module connects the input end of main control module, and main control module is connected main station through communication module, and still has time module to the input end of main control module, its characterized in that: time module includes counter circuit, and the clock input pin of counter circuit is connected to the frequency divider circuit of crystal oscillator, and the clear zero pin of counter circuit is connected to the clear zero signal, and the control signal input end of latching circuit is connected to the GPS module through clock interface, and the data signal input end of latching circuit is connected to the counter circuit, and the clock interface is connected to main control module.

[0006] Further, the clear zero signal is connected to the clear zero pin of the counter circuit through the first opto-isolator module; and the clock interface is connected to the GPS module through the second opto-isolator.

[0007] Further, the output end of the analog-digital conversion module is connected to the input end of a preprocessing module, and the output end of the preprocessing module is connected to the input end of the main control module.

[0008] Further, a signal conditioning module is connected to the output end of the wave collection sensor, and the output end of the signal conditioning module is connected to the input end of the analog-digital conversion module.

[0009] Further, the signal conditioning module includes a filtering circuit and an amplifying circuit connected in sequence, and the output end of the wave collection sensor is connected to the filtering circuit and the amplifying circuit in sequence.

[0010] Further, a power supply module is also provided, and the power supply output end of the power supply module is connected to the signal conditioning module, the analog-digital conversion module, the main control module, and the communication module.

[0011] Further, the power supply module includes an induction coil installed on a power transmission line, the output power supply of the induction coil is connected to an overvoltage protection circuit, the output end of the overvoltage protection circuit is connected to the input end of a rectifier circuit, and the output end of the rectifier circuit is connected to a battery through a power management module.

[0012] Compared with the prior art, the utility model has the beneficial effects that:

[0013] In the wave-based distribution network line fault location system of the present application, the main control module can obtain two time signals with a resolution of 1 microsecond through the time module, thereby improving the continuous reliability of time synchronization.

[0014] Since the GPS signal needs to receive the signal from the satellite in real time, the time synchronization may not be accurate. In order to solve this problem, the pulse clock signal generated after the local crystal oscillator is divided is introduced, thereby improving the continuous reliability of the time synchronization. Through the GPS signal, the system can determine which second the fault occurs, and through the local crystal oscillator division signal, the specific microsecond when the fault occurs can be accurately determined. This combination makes the system more accurate in time positioning, ensuring high reliability and accuracy in fault detection and positioning.

[0015] In the power distribution network line fault positioning system based on the traveling wave of the application, the power supply module is arranged, so that power can be directly taken from the power transmission line, avoiding the need to arrange a separate power supply.

[0016] The pre-processing module is arranged, and the faster processing speed of the FPGA chip is used to pre-process the signal detected by the traveling wave collection sensor. When the FPGA determines that the signal detected by the traveling wave collection sensor meets the preset condition, the main control module further judges the fault, thereby improving the judgment efficiency, reducing the probability of misjudgment, and reducing the operation pressure of the main control module. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a principle block diagram of the power distribution network line fault positioning system based on the traveling wave.

[0018] Figure 2 It is a principle block diagram of the driving module.

[0019] Figure 3 It is a principle block diagram of the time synchronization module.

[0020] Figure 4 It is a principle diagram of the fault distance measurement based on the traveling wave. DETAILED DESCRIPTION

[0021] Figures 1-4 It is the best embodiment of the utility model, and the technical scheme in the embodiment of the utility model will be described clearly and completely in combination with the drawings. Figures 1-4 The utility model is further described.

[0022] The technical scheme in the embodiment of the utility model will be described clearly and completely in combination with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the utility model.

[0023] As Figure 1As shown, a line fault locating system based on traveling wave of power distribution network comprises traveling wave collection sensors arranged in the line, the traveling wave collection sensors are realized by traveling wave sensors known in the art, such as traveling wave sensors realized based on Rogowski coils, which convert the primary varying current signal into a secondary voltage signal, can complete the transmission of voltage traveling wave, and have a differential amplification effect on the wave head, which is beneficial to wave head detection.

[0024] The signal output end of the traveling wave collection sensor is connected with a signal conditioning module, the output end of the signal processing module is connected with the input end of an analog-digital conversion module, and the output end of the analog-digital conversion module is connected with the input end of a pre-judgment module.

[0025] The signal conditioning module comprises a filter circuit and an amplification circuit connected in sequence, the filter circuit is realized by a band-pass filter with a passband of 500 kHz-5 MHz, and the amplification circuit amplifies the input signal of the traveling wave collection sensor by two times. After the signal output by the traveling wave collection sensor is filtered and amplified in sequence, the signal is sent to the analog-digital conversion module, the analog signal is converted into a digital signal by the analog-digital conversion module, and the converted digital signal is sent to the pre-judgment module.

[0026] In the application, the pre-judgment module is realized by an FPGA known in the art, and the output end of the FPGA is connected with a main control module. After the digital signal output by the analog-digital conversion module is sent to the FPGA, the FPGA performs threshold value judgment on the data, when the sampling values of 8 continuous data points exceed the threshold value, the FPGA transmits the data to the main control module in real time, and the main control module further analyzes and stores the data. Therefore, in the application, the pre-processing module is set, the faster processing speed of the FPGA chip is utilized to pre-process the signal detected by the traveling wave collection sensor, when the FPGA judges that the signal detected by the traveling wave collection sensor meets the preset condition, the main control module further judges the fault, the judgment efficiency is improved, the probability of misjudgment is reduced, and the operation pressure of the main control module is reduced.

[0027] A time module is connected with the input end of the main control module, and the main control module determines the absolute time of traveling wave waveform collection through the time module. A communication module is also connected with the input and output ends of the main control module, and the main control module realizes communication with a master station through the communication module.

[0028] In the line fault locating system based on traveling wave of power distribution network, a power taking module is also arranged, and the power taking module is used to supply power to the signal conditioning module, the analog-digital conversion module, the pre-judgment module, the main control module and the communication module. Figure 3The power taking module includes an induction coil installed on the power transmission line, and the output of the induction coil is connected to the overvoltage protection circuit. The overvoltage protection circuit is used for overvoltage protection, and then the AC-DC conversion is realized through the rectifier circuit. The DC voltage output by the rectifier circuit is connected to the storage battery through the power management module known in the art, so as to realize the charging of the storage battery. The power management module is used for controlling the charging and discharging of the storage battery, so as to avoid overcharging or overdischarging of the storage battery.

[0029] A plurality of different voltage conversion chips are connected to the output end of the storage battery. A plurality of different voltage signals are obtained through the voltage conversion chips, so as to meet the different power supply requirements of the signal conditioning module, the analog-digital conversion module, the pre-judgment module, the main control module and the communication module. Therefore, the power distribution network line fault positioning system based on the traveling wave of the present application does not need external power supply.

[0030] As shown in Figure 2 The time synchronization module includes a 20-bit counter circuit and a latch circuit. The counter circuit is composed of a counter chip and its peripheral circuit known in the art. For example, two 74LS160 chips are cascaded to realize the 20-bit counting function.

[0031] The 16Mhz crystal oscillator is connected to the CLK pin of the counter circuit through the frequency division circuit, and the 1PPS signal is connected to the MR pin (clear pin) of the counter circuit through the first photoelectric isolation. The GPS module is connected to the GPS clock interface through the first photoelectric isolation, the GPS clock interface is connected to the control signal input end of the latch circuit, and the counter circuit is connected to the data input end of the latch circuit. The CLK interface of the counter circuit is used to receive the pulse clock signal generated after the frequency division of the crystal oscillator, and the MR interface is used to realize the time clear of the 1PPS every 1S. The counter circuit outputs a microsecond every time it is cleared. The latch circuit is directly connected to the counter circuit and is used to store the microsecond number output by the counter circuit. The working principle is as follows: the GPS first generates a trigger signal, and the latch circuit starts to latch the microsecond number from the counter circuit after receiving the trigger signal.

[0032] The main control module ultimately reads two time signals: one is the time generated by the counting circuit and output through the latching circuit, and the other is the time directly read from the GPS clock interface. Both have a resolution of 1 microsecond, thus improving the continuous reliability of time synchronization. Since GPS signals need to receive signals from satellites in real time, inaccurate time synchronization may occur. To solve this problem, a pulse clock signal generated by frequency division of the local crystal oscillator is introduced, thereby improving the continuous reliability of time synchronization. Using the GPS signal, the system can determine the exact second a fault occurred, while using the frequency-divided signal from the local crystal oscillator allows for precision down to the specific microsecond of the fault occurrence. This combination makes the system more accurate in time positioning, ensuring high reliability and accuracy in fault detection and location.

[0033] The specific working process and working principle are as follows:

[0034] like Figure 4 As shown, monitoring points M and N at both ends of the line are arranged as follows: Figure 1 The fault location system for distribution network lines based on traveling waves, as shown in the figure, uses traveling wave acquisition sensors to collect traveling wave data from both ends of the line in real time.

[0035] The acquired traveling wave data is filtered and amplified by the filtering and amplification circuits in various signal conditioning modules before being sent to the pre-judgment module. The pre-judgment module first performs a pre-judgment on the traveling wave data. When a fault occurs between monitoring point M and monitoring point N, the pre-judgment module determines that a fault has occurred in the line after eight consecutive data point sampling values ​​exceed the threshold. The pre-judgment module then transmits the data to the main control module in real time.

[0036] At this point, the main control module uses the time information sent by the time synchronization module to determine the absolute time of the traveling wave waveform acquisition. After adding a time stamp to the traveling wave waveform, the main control module uploads the traveling wave data to the master station, which then calculates and locates the fault point. The master station's fault location principle is as follows:

[0037] The distances from monitoring points M and N at both ends of the faulty section to the fault point can be expressed as:

[0038] ;

[0039] ;

[0040] Where L represents the distance between the two ends of the fault section, v represents the traveling wave velocity, and TM and TN represent the absolute moments when the monitoring points at both ends of the fault section sense the initial traveling wave of the line fault.

[0041] The main station can use the above formula to calculate the location of the fault.

[0042] While the preferred embodiments of the application have been described, those skilled in the art will recognize that the application can be practiced with modification and alteration within the spirit and scope of the application. Accordingly, the description is to be regarded as illustrative instead of limiting on the scope of the application.

[0043] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A fault location system for distribution network lines based on traveling waves, comprising a traveling wave acquisition sensor, the output terminal of the traveling wave acquisition sensor being connected to the input terminal of an analog-to-digital converter module, the output terminal of the analog-to-digital converter module being connected to the input terminal of a main control module, the main control module being connected to a master station via a communication module, and a time synchronization module being connected to the input terminal of the main control module, characterized in that: The time module comprises a counter circuit, a crystal oscillator is connected to a clock input pin of the counter circuit through a frequency division circuit, a clear signal is connected to a clear pin of the counter circuit, a GPS module is connected to a control signal input end of a latch circuit through a clock interface, the counter circuit is connected to a data signal input end of the latch circuit, and the clock interface is connected to a main control module.

2. The traveling wave based power distribution network line fault location system, as claimed in claim 1 wherein: The clear signal is connected to the clear pin of the counter circuit through a first photoelectric isolation module, and the GPS module is connected to the clock interface through a second photoelectric isolation.

3. The traveling wave based power distribution system line fault location system of claim 1, wherein: An output end of the analog-digital conversion module is connected to an input end of a preprocessing module, and an output end of the preprocessing module is connected to an input end of the main control module.

4. The traveling wave based power distribution system line fault location system of claim 1, wherein: A signal conditioning module is connected to an output end of the traveling wave acquisition sensor, and an output end of the signal conditioning module is connected to an input end of the analog-digital conversion module.

5. The traveling wave based power distribution system line fault location system of claim 1, wherein: The signal conditioning module comprises a filter circuit and an amplification circuit in sequence, and the output end of the traveling wave acquisition sensor is connected to the filter circuit and the amplification circuit in sequence.

6. The traveling wave based power distribution system line fault location system of claim 1, wherein: A power taking module is further arranged, and a power output end of the power taking module is connected to the signal conditioning module, the analog-digital conversion module, the main control module and the communication module.

7. The traveling wave based power distribution network line fault location system, as claimed in claim 6, wherein: The power taking module comprises an induction coil arranged on a power transmission line, an output power of the induction coil is connected to an overvoltage protection circuit, an output end of the overvoltage protection circuit is connected to an input end of a rectifier circuit, and an output end of the rectifier circuit is connected to a battery through a power management module.

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