Protection scheme and system for segmented power supply full parallel AT traction network

Abstract

The invention discloses a protection scheme and system for a segmented power supply full parallel AT traction network, and belongs to the technical field of railway traction network relay protection. The method specifically comprises the following steps: after the full-parallel AT traction network is divided into a plurality of sections, firstly, monitoring the head end current of each section in real time, calculating the effective value of the current, and judging whether a fault occurs or a locomotive passes according to the magnitude of the current; secondly, constructing a current criterion, and judging a fault or a section through which a locomotive passes; and finally, calculating the variable quantity of the current at the head end of the section, judging whether the locomotive passes by or fails according to the variable quantity of the current at the head end, and if the fault is judged, disconnecting circuit breakers at the two sides of the failed section, isolating the fault and protecting the full parallel AT power supply traction network. According to the method, the fault section of the segmented power supply full parallel AT traction network can be rapidly cut off, normal power supply of the traction network in the non-fault section is ensured, the power failure range is narrowed, and the power supply reliability of the full parallel AT traction network is improved.

Description

Technical Field

[0001] The invention relates to a protection scheme and system for a segmented power supply full-parallel AT traction network, belonging to the technical field of railway traction network relay protection. Background Art

[0002] With the development of my country's high-speed railways, the full parallel AT power supply wiring method has been widely used in traction power supply systems due to its high power supply power and high power supply reliability. Configuring accurate and reliable protection schemes and systems is essential to ensure the safe operation of high-speed railways. The full parallel AT traction power supply method has a complex wiring form. When a fault occurs at any position of the power supply arm, the existing protection scheme will cause the traction substation circuit breaker to trip, causing the entire power supply arm to lose power. Especially for the full parallel AT power supply traction network, both the upstream and downstream power supply arms will lose power, and the power outage range will be larger.

[0003] To solve this problem, some scholars have proposed a method of segmenting the traction network. For example, the invention patent with application number 201410624679.1 proposed a distributed protection system for segmented power supply of the electrified railway traction network. This method divides the traction network with direct power supply into several sections and constructs a protection scheme using voltage and current data. This method is convenient and effective for the traction network with direct power supply. However, the wiring of the fully parallel AT power supply traction network is complicated, which affects the practicality of this method. Moreover, for the fully parallel AT power supply traction network, the voltage drop is not obvious, and it is difficult to use the voltage size to distinguish between faults and locomotives passing by, resulting in protection failure, affecting the safe operation of high-speed railways.

[0004] Therefore, it is necessary to further study the segmentation method and protection scheme of the full-parallel AT traction network in order to accurately and timely reduce the scope of power outages to the maximum extent and ensure normal power supply to non-fault sections. Summary of the invention

[0005] The purpose of the present invention is to solve the protection problem of a segmented power supply full parallel AT traction network, and to provide a protection scheme and system for a segmented power supply full parallel AT traction network, which can accurately and timely reduce the scope of power outage to the maximum extent and ensure normal power supply to non-fault sections.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following scheme: a protection scheme and system for a segmented power supply full-parallel AT traction network. After the full-parallel AT traction network is divided into several sections, first, the current at the head end of each section is monitored in real time and the effective value of the current is calculated, and whether a fault occurs or a locomotive passes by is determined according to the current size; secondly, a current judgment criterion is constructed to determine the section where a fault occurs or a locomotive passes by; finally, the change in the current at the head end of the section is calculated, and whether a locomotive passes by or a fault occurs is determined according to the size of the change in the current at the head end. If it is determined to be a fault, the circuit breakers on both sides of the faulty section are disconnected to isolate the fault and protect the full-parallel AT power supply traction network.

[0007] On one hand, the present invention provides a protection scheme for a segmented power supply full-parallel AT traction network, specifically comprising: Step 1: Divide the full parallel AT traction network into sections, and use the current sensors installed at the head end of each section of the full parallel AT traction network with segmented power supply. Monitor the current in real time and calculate the effective value of the current at the head end of each section ,in, , indicating the segmented power supply section of the full parallel AT traction network; Step 2: The effective value of the current at the head end of each section With current setting value Compare, if < , then the segment If it is judged that there is no fault and no locomotive passes, return to Step 1; if ≥ , then construct the segment Current criterion ; Step 3: The current criteria of each section Compared with the current criterion setting value, if , then the segment It is determined that no fault has occurred and no locomotive has passed, and the process returns to Step 1 and Step 2. , then the segment It is judged that a fault has occurred or a locomotive has passed, among which, is the current criterion setting value; Step 4: Calculation Rate of change ,like < , it is determined that a locomotive has passed, and the system returns to continue executing Step 1, Step 2, and Step 3, while locking the section Circuit breakers on both sides; if ≥ , it is judged that there is a fault in the section, and at the same time, the section is disconnected Circuit breakers on both sides and , isolate faults and protect the fully parallel AT power supply traction network, where: It is the setting value of current change rate.

[0008] Furthermore, in Step 1: circuit breakers are connected in series at the station ends of the contact wires T and negative feeder F of the uplink and downlink lines of the full parallel AT traction network. The circuit breakers are installed in traction substations, AT stations and substations, and the full parallel AT traction network is divided into several power supply sections. A measurement and control system CKi is set up in each power supply section, where: , representing the segmented power supply section of the full parallel AT traction network; the measurement and control system CKi receives and processes the current data on both sides of the power supply section, and controls the circuit breakers on both sides of the power supply section.

[0009] Furthermore, the measurement and control system CKi is centrally arranged in the traction substation or dispersedly arranged in the traction substation, AT station and substation.

[0010] Furthermore, in Step 2: the construction method of the current criterion is: ; In the formula, For segment The current criterion, For segment The first current vector, For segment Final current vector.

[0011] Another aspect of the present invention provides a system for a segmented power supply full parallel AT traction network, specifically comprising: Data acquisition module: collects the current at the head end of each section of the segmented power supply full parallel AT traction network in real time, and converts the collected analog signals into digital signals; Data processing module: calculates the effective value of the head-end current, current criterion and the change in the effective value of the current and compares them; Circuit breaker control module: Open the circuit breaker or keep the short circuit breaker closed according to the logic processing results.

[0012] The beneficial effects of the present invention are: 1. The present invention reasonably segments the full parallel AT power supply traction network, and each section is equipped with a measurement and control system. The measurement and control system can be centrally configured in the traction substation or dispersedly arranged in the traction substations, AT stations and substations in each section, which is easy to implement.

[0013] 2. The present invention only uses current information, thus overcoming the protection failure problem caused by small voltage change after the AT autotransformer is connected to the traction.

[0014] 3. The current criterion adopted by the present invention is the current ratio. When there is a fault or a locomotive passes through a section, the ratio is infinite. When there is no fault and no locomotive passes through a section, the ratio is zero. The setting value is not affected by the short-circuit capacity of the system and is a theoretical value, which is convenient for setting.

[0015] In summary, the present invention reasonably segments the fully parallel AT power supply traction network, constructs a complete protection scheme and system using only current data, isolates the faulty section promptly and accurately, minimizes the scope of power outages, improves the power supply reliability of the traction network, and ensures the safe operation of high-speed railways. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to better understand the above technical scheme, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art, and the accompanying drawings of the present invention are as follows.

[0017] Figure 1 This is a structural diagram of the segmented power supply full parallel AT traction network of the present invention; Figure 2 This is a flow chart of the protection scheme for the segmented power supply full parallel AT traction network of the present invention; Figure 3 This is a module block diagram of the segmented power supply full parallel AT traction network protection system of the present invention; Figure 4 The waveform diagram and effective value of the current at the head end of each section in Example 1 of the present invention; Figure 5 The waveform diagram and effective value of the current at the head end of each section in Example 2 of the present invention; Figure 6 The current waveform diagram at the beginning and end of sections 1, 2, 4, 7, and 10 in Example 2 of the present invention; Figure 7 This is a waveform diagram of the current change at the head end of section 2 in embodiment 2 of the present invention; Figure 8 The waveform diagram and effective value of the current at the head end of each section in Example 3 of the present invention; Fig. 9 The current waveform diagram at the beginning and end of sections 1, 2, 4, and 5 in Example 3 of the present invention; Fig.10 The current waveform diagram at the beginning and end of sections 7, 8, 10, and 11 in Example 3 of the present invention; Fig.11 This is a waveform diagram of the current change at the head end of section 2 in embodiment 3 of the present invention. DETAILED DESCRIPTION

[0018] 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 only 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 are within the scope of protection of the present invention.

[0019] The purpose of the present invention is to provide a protection scheme and system for a segmented power supply full parallel AT traction network, aiming to accurately and timely discover faults, and minimize the power outage scope of the full parallel AT power supply traction network, ensure normal power supply to non-fault sections, and ensure safe operation of high-speed railways. The present invention is further described below in conjunction with specific implementation methods.

[0020] Embodiment 1: This embodiment is based on Figure 1 As shown in the structural diagram, a segmented power supply full parallel AT traction network model is built in the PSCAD / EMTDC electromagnetic transient simulation software. The traction system consists of a traction substation, two AT stations and a substation. Set to 200A, Set to 1, The setting is 15A / ms. In this embodiment, the traction network is set to have no faults and no locomotives pass by.

[0021] According to Figure 2 and Figure 3 The protection scheme and system of the segmented power supply full parallel AT traction network shown in the figure include the following specific steps:

[0022] Step 1: Divide the full parallel AT traction network into sections. This traction system is divided into 12 sections, namely: Section 1 (upward T line traction substation-AT1), Section 2 (upward T line AT1-AT2), Section 3 (upward T line AT2-district substation), Section 4 (upward F line traction substation-AT1), Section 5 (upward F line AT1-AT2), Section 6 (upward F line AT2-district substation), Section 7 (downward T line traction substation-AT1), Section 8 (downward T line AT1-AT2), Section 9 (downward T line AT2-district substation), Section 10 (downward F line traction substation-AT1), Section 11 (downward F line AT1-AT2), Section 12 (downward F line AT2-district substation); Current sensors at the head end of each section , , , , , , , , , , and Real-time monitoring of current and calculation of current effective value , , , , , , , , , , and ,like Figure 4 shown.

[0023] Step 2: The effective value of the current at the head end of each section , , , , , , , , , , and With current setting value Comparison, both less than ,like Figure 4 As shown, it means that sections 1-12 have no faults and no locomotive passes through, and the process returns to Step 1.

[0024] Embodiment 2: This embodiment is based on Figure 1 As shown in the structural diagram, a segmented power supply full parallel AT traction network model is built in the PSCAD / EMTDC electromagnetic transient simulation software. The traction system consists of a traction substation, two AT stations and a substation. Set to 200A, Set to 1, The setting is 15A / ms. In this embodiment, the traction network locomotive passes through section 2.

[0025] According to Figure 2 and Figure 3 The protection scheme and system of the segmented power supply full parallel AT traction network shown in the figure include the following specific steps:

[0026] Step 1: Divide the full parallel AT traction network into sections. This traction system is divided into 12 sections, namely: Section 1 (upward T line traction substation-AT1), Section 2 (upward T line AT1-AT2), Section 3 (upward T line AT2-district substation), Section 4 (upward F line traction substation-AT1), Section 5 (upward F line AT1-AT2), Section 6 (upward F line AT2-district substation), Section 7 (downward T line traction substation-AT1), Section 8 (downward T line AT1-AT2), Section 9 (downward T line AT2-district substation), Section 10 (downward F line traction substation-AT1), Section 11 (downward F line AT1-AT2), Section 12 (downward F line AT2-district substation); Current sensors at the head end of each section , , , , , , , , , , and Real-time monitoring of current and calculation of current effective value , , , , , , , , , , and ,like Figure 5 shown.

[0027] Step 2: The effective value of the current at the head end of each section , , , , , , , , , , and With current setting value By comparison, Figure 5 It can be seen , , , , Greater than the current setting value ,use Figure 6The current at both ends of sections 1, 2, 4, 7 and 10 shown constitutes the current criterion , , , and , calculated: , , , , .

[0028] Step 3: Set the current criteria of sections 1, 2, 4, 7 and 10 , , , and And the current criterion setting value Compare, , , and < Therefore, it is determined that no fault has occurred in sections 1, 4, 7, and 10, and no locomotive has passed through, and the process returns to continue executing Step 1 and Step 2; ≥ Therefore, section 2 is judged as having a fault or a locomotive passing by.

[0029] Step 4: Calculation Rate of change ,like Figure 7 As shown, < , it is determined that a locomotive has passed, and the system returns to continue executing Step 1, Step 2, and Step 3, while locking the circuit breakers on both sides of section 2 and .

[0030] Embodiment 3: This embodiment is based on Figure 1 As shown in the structural diagram, a segmented power supply full parallel AT traction network model is built in the PSCAD / EMTDC electromagnetic transient simulation software. The traction system consists of a traction substation, two AT stations and a substation. Set to 200A, Set to 1, The setting is 15A / ms. In this embodiment, it is assumed that the traction network section 2 has a fault.

[0031] According to Figure 2 and Figure 3 The protection scheme and system of the segmented power supply full parallel AT traction network shown in the figure include the following specific steps:

[0032] Step 1: Divide the full parallel AT traction network into sections. This traction system is divided into 12 sections, namely: Section 1 (upward T line traction substation-AT1), Section 2 (upward T line AT1-AT2), Section 3 (upward T line AT2-district substation), Section 4 (upward F line traction substation-AT1), Section 5 (upward F line AT1-AT2), Section 6 (upward F line AT2-district substation), Section 7 (downward T line traction substation-AT1), Section 8 (downward T line AT1-AT2), Section 9 (downward T line AT2-district substation), Section 10 (downward F line traction substation-AT1), Section 11 (downward F line AT1-AT2), Section 12 (downward F line AT2-district substation); Current sensors at the head end of each section , , , , , , , , , , and Real-time monitoring of current and calculation of current effective value , , , , , , , , , , and ,like Figure 8 shown.

[0033] Step 2: The effective value of the current at the head end of each section , , , , , , , , , , and With current setting value By comparison, Figure 8 It can be seen , , , , , , , Greater than the current setting value ,use Fig. 9 and Fig.10 The current at both ends of sections 1, 2, 4, 5, 7, 8, 10 and 11 shown constitutes the current criterion , , , , , , and , calculated: , , , , , , , .

[0034] Step 3: Set the current criteria of sections 1, 2, 4, 5, 7, 8, 10 and 11 , , , , , , and And the current criterion setting value Compare, , , , , , and < Therefore, it is determined that no fault has occurred in sections 1, 4, 5, 7, 8, 10, and 11, and no locomotive has passed through, and the process returns to continue executing Step 1 and Step 2; ≥ Therefore, section 2 is judged as having a fault or a locomotive passing by.

[0035] Step 4: Calculation Rate of change ,like Fig.11 As shown, ≥ , it is judged that there is a fault in this section, and at the same time, the circuit breakers on both sides of section 2 are disconnected and , isolate faults and protect the fully parallel AT power supply traction network.

[0036] In summary, the present invention can reliably identify the situations in which the full-parallel AT traction network is not faulty, the locomotive is passing, and the faulty section can be isolated promptly and accurately, thereby minimizing the scope of power outages, improving the power supply reliability of the traction network, and ensuring the safe operation of high-speed railways.

[0037] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A protection scheme for a segmented power supply full parallel AT traction network, characterized by: Step 1: Divide the full parallel AT traction network into sections, and use the current sensors installed at the head end of each section of the full parallel AT traction network with segmented power supply. Monitor the current in real time and calculate the effective value of the current at the head end of each section ,in, , indicating the segmented power supply section of the full parallel AT traction network; Step 2: The effective value of the current at the head end of each section With current setting value Compare, if < , then the segment If it is judged that there is no fault and no locomotive passes, return to Step 1; if ≥ , then construct the segment Current criterion ; Step 3: The current criterion of each section Compared with the current criterion setting value, if , then the segment It is determined that no fault has occurred and no locomotive has passed, and the process returns to Step 1 and Step 2. , then the segment It is judged that a fault has occurred or a locomotive has passed, among which, is the current criterion setting value; Step 4: Calculate the current at the beginning of each section Rate of change ,like < , it is determined that a locomotive has passed, and the process returns to continue executing Step 1, Step 2, and Step 3, while locking the section. Circuit breakers on both sides and ;like ≥ , then the section is judged to be faulty and the section is disconnected Circuit breakers on both sides and , isolate faults and protect the fully parallel AT power supply traction network, where: It is the setting value of current change rate.

2. The protection scheme for a segmented power supply full parallel AT traction network according to claim 1 is characterized by: In the Step 1, circuit breakers are connected in series at the station ends of the contact wires T and negative feeder F of the uplink and downlink lines of the full parallel AT traction network. The circuit breakers are installed in traction substations, AT stations and substations, and the full parallel AT traction network is divided into several power supply sections. A measurement and control system CKi is set in each power supply section, wherein: , representing the segmented power supply section of the full parallel AT traction network; the measurement and control system CKi receives and processes the current data on both sides of the power supply section, and controls the circuit breakers on both sides of the power supply section.

3. The protection scheme for a segmented power supply full parallel AT traction network according to claim 2 is characterized by: The measurement and control system CKi is centrally arranged in the traction substation or dispersedly arranged in the traction substation, AT station and substation.

4. The protection scheme for a segmented power supply full parallel AT traction network according to claim 1 is characterized by: In Step 2, the construction method of the current criterion is: ; In the formula, For segment The current criterion, For segment The first current vector, For segment Final current vector.

5. A protection system for a segmented power supply full parallel AT traction network, characterized in that A protection scheme for a segmented power supply full-parallel AT traction network according to any one of claims 1 to 4 is implemented, comprising: Data acquisition module: collects the current at the head end of each section of the segmented power supply full parallel AT traction network in real time, and converts the collected analog signals into digital signals; Data processing module: calculates the effective value of the head-end current, current criterion and the change in the effective value of the current and compares them; Circuit breaker control module: Open the circuit breaker or keep the circuit breaker closed according to the data processing results.

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