Catenary fault branch determination system and method based on bypass shunt mode

Abstract

The application discloses a kind of contact network fault branch determination system and method based on bypass shunt mode, it is applied to the contact network with branch, wherein the system includes branch current transformer, feeder current transformer and measurement and control device, branch current transformer is installed in the first contact network branch head with bypass shunt mode, obtains the partial current of first contact network branch i b1p ; measurement and control device obtains feeder current i f And the partial current of first contact network branch i b1p , independently calculates and calibrates bypass shunt coefficient k , to calculate the complete current of first contact network branch i b1 And the current of second contact network branch i b2 ; when fault occurs, the current mutation of each branch is calculated, by comparing the current mutation of first contact network branch and second contact network branch, whether the fault of contact network is located in first contact network branch is determined.The application avoids the determination dead zone caused by branch current transformer series installation mode, and improves the operation safety and fault positioning efficiency of contact network.

Description

Technical Field

[0001] This invention belongs to the field of traction power supply measurement and control technology for electrified railways, specifically relating to the design of a contact network fault branch determination system and method based on bypass diversion. Background Technology

[0002] Electrified railway catenary systems are exposed to the elements and have complex structures, leading to frequent faults. Rapid and accurate fault location is crucial for minimizing power outages and losses. While existing traction substation feeder protection devices possess fault location capabilities, when the catenary has branches (e.g., the feeder connection point is not at the end of the catenary), the location measurement results may correspond to multiple locations on different branches, resulting in inconsistent fault locations and delays in emergency repairs.

[0003] To address this issue, existing technologies propose connecting current transformers in series in the contact network branches to aid in fault location, determining the branch where the fault is located by measuring the current in that branch. However, this method of installing current transformers in series in the contact network has significant drawbacks: the current transformers must be installed at the electrical connection points of the contact network anchor sections. If this location differs from the feeder connection point, a dead zone of up to approximately 2 km will be created near the connection point, preventing the correct identification of faults within that area. Furthermore, connecting current transformers in series makes the current transformers and their leads part of the main conductive circuit, meaning that a fault will directly impact the safety of the contact network power supply. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing method of measuring the current of the contact network branch by connecting the current transformer in series in the contact network. It proposes a contact network fault branch judgment system and method based on bypass current shunting. The contact network branch current is obtained by bypass current shunting, the complete branch current is restored by self-calibrated current shunting coefficient, and the contact network fault branch is accurately judged by utilizing the current change characteristics at the time of the fault.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a contact network fault branch determination system based on bypass diversion, applicable to contact networks with branches, comprising:

[0006] Branch current transformer CT b It is installed at the beginning of the first contact wire branch in a bypass shunt manner to obtain part of the current of the first contact wire branch. i b1p .

[0007] Measurement and control device, and branch current transformer (CT) b Connection for receiving current from the first contact network branch. i b1p .

[0008] Feeder current transformer (CT) f Installed at the beginning of the feeder, it is used to obtain the feeder current. i f And send it to the monitoring and control device.

[0009] The measurement and control device is configured as follows:

[0010] Based on feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k Based on bypass shunt coefficient k Calculate the complete current of the first contact wire branch. i b1 Second contact network branch current i b2 ; Calculate the current change of each branch at the moment of the fault; compare the current change of the first contact network branch with the current change of the second contact network branch to determine whether the contact network fault is located in the first contact network branch.

[0011] Furthermore, the measurement and control device includes a CPU module, as well as analog input modules, digital input modules, digital output modules, power supply modules, communication modules, and human-machine interface modules, all of which are connected to the CPU module. The CPU module is configured to perform bypass shunt coefficient calibration, branch current calculation, and fault determination.

[0012] Furthermore, the branch current transformer (CT) b The high-voltage end is electrically connected to two points on the first contact network branch, and is connected in a bypass shunt manner to measure the current flowing through the branch current transformer (CT). b Current in the first contact wire branch i b1p .

[0013] Furthermore, the branch current transformer (CT) b An electronic current transformer is used to transmit digital signals to the communication module of the measurement and control device via optical fiber.

[0014] Furthermore, the measurement and control device is configured as follows:

[0015] Continuously cache part of the current in the first contact network branch i b1p and feeder current i f ; in response to feeder current i f If the value is greater than the set value, calculate. i b1p and i fThe ratio of the two values ​​is used, and the maximum value of the ratio is selected as the bypass shunt coefficient. k According to the formula i b1 = i b1p / k Calculate the complete current of the first contact wire branch. i b1 And according to the formula i b2 = i f - i b1 Calculate the current in the second contact wire branch. i b2 After receiving the feeder protection action signal, the buffered current data of the fault process is extracted, the current change of each branch is calculated, and the faulty branch is determined based on the comparison result of the current change.

[0016] Furthermore, the measurement and control device can be an independent device or integrated with the feeder protection measurement and control device, and it can be used to determine faults.

[0017] Secondly, the present invention provides a method for determining faulty branches of overhead contact lines based on bypass diversion, applicable to overhead contact lines with branches, comprising the following steps:

[0018] Obtain the current of the first contact wire branch i b1p and feeder current i f .

[0019] Based on feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k .

[0020] Based on the current in the first contact wire branch i b1p and bypass shunt coefficient k Calculate the complete current of the first contact wire branch. i b1 And based on the feeder current i f Complete current of the first contact wire branch i b1 Calculate the current in the second contact wire branch. i b2 .

[0021] Calculate the sudden change in current in each branch at the moment the fault occurs.

[0022] The current change in the first contact wire branch is compared with that in the second contact wire branch to determine whether the contact wire fault is located in the first contact wire branch.

[0023] Furthermore, the bypass shunt coefficient is calculated and calibrated. k The specific method is as follows:

[0024] Continuously collect partial current of the first contact network branch i b1p and feeder current i f .

[0025] Response to feeder current i f If the value is greater than the set value, calculate the temporary bypass diversion coefficient. k '= i b1p / i f .

[0026] Response to temporary bypass shunt coefficient k 'Greater than the current storage bypass shunt coefficient' k And it is an effective value, the bypass shunt coefficient k Updated to temporary bypass diversion coefficient k '.

[0027] Furthermore, the formula for calculating the sudden change in current is Δ i t = i t - i t-T Where T is one power frequency cycle, i t The current value at the current sampling point. i t-T This represents the current value at the sampling point corresponding to the previous power frequency cycle.

[0028] Furthermore, the specific method for determining whether a fault in the overhead contact line is located in the first overhead contact line branch is as follows:

[0029] During the fault process, locate the two consecutive power frequency cycles with the largest absolute value of the feeder current change.

[0030] The reference time is the moment when the absolute value of the feeder current change is the largest in the earlier cycle.

[0031] Compare the magnitudes of the current surges in the first and second contact wire branches at the reference time.

[0032] If the sudden change in current in the first contact wire branch is large, the fault is determined to be located in the first contact wire branch; otherwise, the fault is determined not to be located in the first contact wire branch.

[0033] The beneficial effects of this invention are:

[0034] (1) Elimination of judgment dead zone: The branch current transformer CT in this invention b Installed using a bypass shunt method, it is not limited by the position of the anchor section joint and can be installed near the grid connection point, completely solving the judgment dead zone problem caused by the series installation method of current transformers.

[0035] (2) Improved safety: The branch current transformer (CT) in this invention b It is no longer connected in series with the main conductive circuit of the contact network, thus avoiding the risk of power outage to the contact network caused by its own fault.

[0036] (3) Adaptive calibration: The present invention can autonomously calculate and calibrate the bypass shunt coefficient, adapt to the differences in on-site installation and the parameter changes that may be caused by long-term operation, and improve the measurement accuracy and system reliability.

[0037] (4) Strong anti-interference ability: The present invention adopts the current mutation algorithm, which effectively filters out the load current components with complex numerical relationships and distribution states, and extracts the mutation characteristics caused by the fault, making the branch judgment more accurate and reliable.

[0038] (5) Low implementation cost: This invention only requires the addition of one current transformer and one measurement and control device. The current transformer is installed near the network access point, the transmission cable is short, the construction is convenient, and the construction cost is low. Attached Figure Description

[0039] Figure 1 The figure shown is a schematic diagram of the contact network fault branch determination system based on bypass diversion method provided in Embodiment 1 of the present invention.

[0040] Figure 2 The diagram shown is a structural block diagram of the measurement and control device provided in Embodiment 1 of the present invention.

[0041] Figure 3 The diagram shown is a flowchart of the autonomous calculation and calibration of the bypass shunt coefficient provided in Embodiment 1 of the present invention.

[0042] Figure 4 The diagram shown is a flowchart of the fault branch determination method provided in Embodiment 1 of the present invention.

[0043] Figure 5 The figure shown is a schematic diagram of the integrated fault location and feeder protection system provided in Embodiment 2 of the present invention.

[0044] Figure 6 The diagram shown is a flowchart of the integrated fault location and feeder protection method provided in Embodiment 2 of the present invention. Detailed Implementation

[0045] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the invention, and are not intended to limit the scope of the invention.

[0046] Example 1:

[0047] This invention provides a contact network fault branch determination system based on bypass diversion, applicable to contact networks with branches, such as... Figure 1 As shown, it includes:

[0048] Branch current transformer CT b It is installed at the beginning of the first contact wire branch in a bypass shunt manner (rather than in series) to obtain part of the current of the first contact wire branch. i b1p .

[0049] The monitoring and control device is installed in the substation control room and is connected to the branch current transformer (CT). b Connection for receiving current from the first contact network branch. i b1p .

[0050] Feeder current transformer (CT) f Installed at the beginning of the feeder, it is used to obtain the feeder current. i f The data is then sent to the measurement and control device. In this embodiment of the invention, the feeder current data can also be obtained from the integrated automation system via a communication network.

[0051] The measurement and control device is configured as follows:

[0052] Based on feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k Based on bypass shunt coefficient k Calculate the complete current of the first contact wire branch. i b1 Second contact network branch current i b2 ; Calculate the current change of each branch at the moment of the fault; compare the current change of the first contact network branch with the current change of the second contact network branch to determine whether the contact network fault is located in the first contact network branch.

[0053] In embodiments of the present invention, such as Figure 2 As shown, the measurement and control device includes a CPU module and analog input modules (for acquiring feeder current) connected to the CPU module. if and the current in the first contact wire branch i b1p The system includes a digital input module (receiving feeder protection action signals), a digital output module (outputting power failure signals from the monitoring and control device), a power supply module (converting externally supplied DC power into the power required for the monitoring and control device to operate), a communication module (receiving clock synchronization signals and electronic current transformer data, exchanging data with the integrated automation system or intelligent traction substation), and a human-machine interface module (data viewing, parameter setting, and maintenance). The CPU module is configured to perform bypass shunt coefficient calibration, branch current calculation, and fault determination.

[0054] Branch current transformer CT b Two points on the high-voltage end and the first contact wire branch ( Figure 1 The electrical connection between points A and B in the circuit is used to bypass the current flow through the branch current transformer (CT). b Current in the first contact wire branch i b1p .

[0055] In this embodiment of the invention, the branch current transformer (CT) b An electronic current transformer is used to transmit digital signals to the communication module of the measurement and control device via optical fiber.

[0056] In this embodiment of the invention, the measurement and control device is configured as follows:

[0057] Continuously cache part of the current in the first contact network branch i b1p and feeder current i f ; in response to feeder current i f If the value is greater than the set value, calculate. i b1p and i f The ratio of the two values ​​is used, and the maximum value of the ratio is selected as the bypass shunt coefficient. k According to the formula i b1 = i b1p / k Calculate the complete current of the first contact wire branch. i b1 And according to the formula i b2 = i f - i b1 Calculate the current in the second contact wire branch. i b2After receiving the feeder protection action signal, the buffered current data of the fault process is extracted, the current change of each branch is calculated, and the faulty branch is determined based on the comparison result of the current change.

[0058] In this embodiment of the invention, the measurement and control device is an independent device that performs fault determination to form a catenary fault branch determination system. Based on this, this embodiment of the invention also provides a catenary fault branch determination method based on bypass diversion, applicable to catenaries with branches, comprising the following steps:

[0059] Obtain the current of the first contact wire branch i b1p and feeder current i f According to the feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k According to the current in the first contact wire branch i b1p and bypass shunt coefficient k Calculate the complete current of the first contact wire branch. i b1 And based on the feeder current i f Complete current of the first contact wire branch i b1 Calculate the current in the second contact wire branch. i b2 ; Calculate the current change of each branch at the moment of the fault; compare the current change of the first contact network branch with the current change of the second contact network branch to determine whether the contact network fault is located in the first contact network branch.

[0060] In embodiments of the present invention, such as Figure 3 As shown, the bypass shunt coefficient is calculated and calibrated. k The specific method is as follows:

[0061] Continuously collect partial current of the first contact network branch i b1p and feeder current i f ; in response to feeder current i f If the value is greater than the set value (e.g., 500A), calculate the temporary bypass shunt coefficient. k '= i b1p / i f ; Response to temporary bypass shunt coefficient k 'Greater than the current storage bypass shunt coefficient'k And it is a valid value (e.g., no abnormal fluctuations, within a reasonable range of 0~1), so the bypass shunt coefficient is... k Updated to temporary bypass diversion coefficient k This iterative process can automatically track and lock the maximum value, enabling autonomous calibration of the bypass shunt coefficient.

[0062] In this embodiment of the invention, the formula for calculating the sudden change in current is Δ i t = i t - i t-T Where T is one power frequency cycle, and in this embodiment of the invention, T = 0.02s. i t The current value at the current sampling point. i t-T This represents the current value at the sampling point corresponding to the previous power frequency cycle.

[0063] In embodiments of the present invention, such as Figure 4 As shown, the specific method for determining whether a fault in the overhead contact line is located in the first overhead contact line branch is as follows: the main program continuously caches current data (current data of the first overhead contact line branch). i b1p and feeder current i f When a feeder protection action signal is received via the digital input module, the buffered data before and after the fault is extracted. The complete current of the first contact network branch is then calculated. i b1 Current in the second contact network branch i b2 Based on the current surge at each sampling point of each branch, within the fault data window, find the two consecutive power frequency cycles with the largest absolute value of the feeder current surge, and use the moment with the largest absolute value of the feeder current surge in the earlier cycle as the reference moment. t 0. Finally, compare with the reference time. t The sudden change in current Δ of the first contact wire branch at 0 i b1t0 The sudden change in current Δ of the second contact wire branch i b2t0 If the sudden change in current Δ of the first contact network branch i b1t0 If the fault is large, the fault is determined to be located in the first contact wire branch; otherwise, the fault is determined to be located outside the first contact wire branch. The determination result can be uploaded to the integrated automation system via the communication module.

[0064] Example 2:

[0065] This invention improves upon the overhead contact line fault branch determination system based on bypass shunting provided in Embodiment 1 by integrating the fault branch determination function of the measurement and control device with the hardware of the feeder protection measurement and control device to form a protection measurement and control device, thereby constituting a system integrating fault location and feeder protection, such as... Figure 5 As shown, this protection and control device simultaneously collects the bus voltage. u b Feeder current i f and the current in the first contact wire branch i b1p .

[0066] Based on this, embodiments of the present invention also provide a method for integrating fault location and feeder protection, such as... Figure 6 As shown, it includes the following steps:

[0067] The protection and control device continuously buffers the bus voltage. u b Feeder current i f and the current in the first contact wire branch i b1p It judges the feeder current in real time and calculates protection parameters such as measured impedance and current surge. When any protection parameter reaches the set value, the protection logic is activated and the current time is recorded. t 0. After a set delay, the protection and control device outputs a control to trip the feeder circuit breaker. The protection and control device then extracts the bus voltage from the buffer. u b Feeder current i f and the current in the first contact wire branch i b1p On the one hand, utilize u b / i f The fault reactance is calculated by taking its imaginary part, and the fault distance is obtained through the reactance-distance comparison table. L On the other hand, the branch determination process is executed simultaneously to calculate the complete current of the first contact network branch. i b1 Second contact network branch current i b2 Calculate based on this t The sudden change in current Δ of the first contact network branch at time 0 i b1t0 The sudden change in current Δ of the second contact network branch i b2t0 The two are compared, and the final judgment result is combined to determine the distance. LMapped to the corresponding overhead contact line branch, a unique fault kilometer marker is output to achieve accurate fault location.

[0068] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A contact network fault branch determination system based on bypass diversion, applied to contact networks with branches, characterized in that, include: Branch current transformer CT b It is installed at the beginning of the first contact wire branch in a bypass shunt manner to obtain part of the current of the first contact wire branch. i b1p ; The measurement and control device, and the branch current transformer CT b Connection for receiving part of the current from the first contact wire branch. i b1p ; Feeder current transformer (CT) f Installed at the beginning of the feeder, it is used to obtain the feeder current. i f And send it to the measurement and control device; The measurement and control device is configured as follows: According to the feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k ; Based on the bypass diversion coefficient k Calculate the complete current of the first contact wire branch. i b1 Second contact network branch current i b2 ; Calculate the sudden change in current in each branch at the moment the fault occurs; Compare the current surge of the first contact wire branch with the current surge of the second contact wire branch to determine whether the contact wire fault is located in the first contact wire branch. The measurement and control device is also configured to: Continuously cache part of the current in the first contact wire branch i b1p and feeder current i f ; Response to feeder current i f If the value is greater than the set value, calculate. i b1p and i f The ratio of the two values ​​is used to select the maximum value of the ratio as the bypass shunt coefficient. k ; According to the formula i b1 = i b1p / k Calculate the complete current of the first contact wire branch. i b1 And according to the formula i b2 = i f - i b1 Calculate the current in the second contact wire branch. i b2 ; After receiving the feeder protection action signal, the buffered current data of the fault process is extracted, the current change of each branch is calculated, and the faulty branch is determined based on the comparison result of the current change.

2. The contact network fault branch determination system based on bypass diversion method according to claim 1, characterized in that, The measurement and control device includes a CPU module, as well as an analog input module, a digital input module, a digital output module, a power supply module, a communication module, and a human-machine interface module, all of which are connected to the CPU module. The CPU module is configured to perform bypass shunt coefficient calibration, branch current calculation, and fault determination.

3. The contact network fault branch determination system based on bypass diversion method according to claim 1, characterized in that, The branch current transformer CT b The high-voltage end is electrically connected to two points on the first contact network branch, and is connected in a bypass shunt manner to measure the current flowing through the current transformer CT of the branch. b Current in the first contact wire branch i b1p .

4. The contact network fault branch determination system based on bypass diversion method according to claim 2, characterized in that, The branch current transformer CT b An electronic current transformer is used to transmit digital signals to the communication module of the measurement and control device via optical fiber.

5. The contact network fault branch determination system based on bypass diversion method according to claim 1, characterized in that, The measurement and control device is an independent device, or it can be integrated with the feeder protection measurement and control device and used to determine faults.

6. A method for determining faulty branches in a contact network based on bypass current diversion, applicable to contact networks with branches, characterized in that, Includes the following steps: Obtain the current of the first contact wire branch i b1p and feeder current i f ; According to the feeder current i f and the current in the first contact wire branch i b1p Calculate and calibrate the bypass shunt coefficient. k ; Based on the current of the first contact wire branch i b1p and the bypass shunt coefficient k Calculate the complete current of the first contact wire branch. i b1 And according to the feeder current i f Complete current of the first contact wire branch i b1 Calculate the current in the second contact wire branch. i b2 ; Calculate the sudden change in current in each branch at the moment the fault occurs; Compare the current surge of the first contact wire branch with the current surge of the second contact wire branch to determine whether the contact wire fault is located in the first contact wire branch. The calculation and calibration of the bypass shunt coefficient k The specific method is as follows: Continuously collect the current of the first contact wire branch. i b1p and feeder current i f ; Response to feeder current i f If the value is greater than the set value, calculate the temporary bypass diversion coefficient. k '= i b1p / i f ; Response to temporary bypass shunt coefficient k 'Greater than the current storage bypass shunt coefficient' k And it is an effective value, the bypass shunt coefficient k Updated to temporary bypass diversion coefficient k '.

7. The method for determining faulty branches of overhead contact lines based on bypass diversion as described in claim 6, characterized in that, The formula for calculating the sudden change in current is Δ i t = i t - i t-T Where T is one power frequency cycle, i t The current value at the current sampling point. i t-T This represents the current value at the sampling point corresponding to the previous power frequency cycle.

8. The method for determining faulty branches of overhead contact lines based on bypass diversion as described in claim 6, characterized in that, The method for determining whether a fault in the overhead contact line is located in the first overhead contact line branch is as follows: During the fault process, locate the two consecutive power frequency cycles with the largest absolute values ​​of the feeder current change. The reference time is the moment when the absolute value of the feeder current change is the largest in an earlier cycle. Compare the magnitudes of the current surges in the first and second contact wire branches at the reference time. If the sudden change in current in the first contact wire branch is large, the fault is determined to be located in the first contact wire branch; otherwise, the fault is determined not to be located in the first contact wire branch.

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