Fault distance measurement method for bilateral full-parallel direct supply traction network
By measuring the current of the traction substation and the cross-sectional characteristics of the parallel line, and calculating the distance between the fault point and the traction substation, the problem of fault distance measurement of bilateral fully parallel direct supply traction network is solved, and the fault interval and line identification and accuracy of fault determination are achieved.
Patent Information
- Application Number
- CN202411504216.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-03-04
AI Technical Summary
When a bilateral fully parallel direct supply traction network fails, the current flow path is complicated and the current at the parallel line cannot be directly measured. The existing fault ranging method is not applicable, which leads to difficulty in determining obstacles.
By measuring the downstream and upstream feeder currents of the traction substation, and combining the cross-section and current characteristics of the parallel lines, the distance from the fault point to the traction substation is calculated, and the fault interval and line difference are identified.
The fault ranging of the bilateral fully parallel direct supply traction network is realized, the fault range and line distance are identified, the accuracy and efficiency of fault determination are improved, and fault handling and operation inspection and maintenance of electrified railways are supported.
Smart Images
Figure CN119556051A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of electrified railway power supply, in particular to a fault distance measurement method for a bilateral full-parallel direct-supply traction network. Background Art
[0002] The power supply mode of the traction network is determined by the technical requirements and economic performance of its special power transmission function. When the traction power supply system adopts the bilateral full parallel direct power supply mode, the upstream and downstream traction networks are not only connected in parallel at the sub-district, but also a parallel line is added between the traction substation and the sub-district. This power supply mode has a strong power supply capacity, can better balance the voltage difference between the upstream and downstream traction networks, effectively suppress the voltage level fluctuation of the traction network, and reduce voltage and power loss.
[0003] The topology of the traction network under the bilateral full-parallel direct supply mode has changed greatly compared with the unilateral power supply and the traditional bilateral direct power supply. Due to the existence of parallel lines, when a short circuit fault occurs, the flow path of the current in the traction network will be more complicated, and the parallel lines are not equipped with current transformers, and the current cannot be directly measured and obtained. Therefore, the current distribution at the time of the fault and its measurement and collection are very different from the traditional bilateral double-line direct supply. The reactance method used for fault ranging in the unilateral single-line direct power supply traction network and the uplink and downlink current ratio method used for fault ranging in the parallel traction network at the end of the unilateral double-line direct supply are no longer applicable to fault ranging under the bilateral power supply mode. In addition, the prior art on the fault ranging of the double-line traction network in the bilateral direct supply mode does not consider the full parallel form.
[0004] Therefore, a new fault distance measurement technology is needed for the bilateral fully parallel direct-supply traction network to improve the fault location and troubleshooting work of electrified railways. Summary of the invention
[0005] The present invention provides a fault distance measurement method for a bilateral fully parallel direct-supply traction network, which solves the problem of being unable to directly obtain the measured current at the parallel line BL by introducing the cross section and current of the parallel line BL, provides a distance measurement method from the traction substation to the fault point, and realizes the identification of the fault section and the fault line.
[0006] The technical solution of the present invention is as follows:
[0007] A fault distance measurement method for a bilateral full parallel direct supply traction network, wherein the fault is a short circuit fault in a SP section from a traction substation to a substation, comprising:
[0008] Measuring the downstream feeder current of traction substation and upstream feeder current Measuring the downstream feeder current from the substation SP to the traction substation and upstream feeder current like and The distance from the fault point to the traction substation is
[0009]
[0010] like and The distance from the fault point to the traction substation is
[0011]
[0012] like and The fault point is located on the parallel line BL, and the distance from the fault point to the traction substation is
[0013] x=D1;
[0014] like and The distance from the fault point to the traction substation is
[0015]
[0016] Wherein, D1 is the distance from the traction substation to the parallel line BL, and D2 is the distance from the parallel line BL to the substation SP;
[0017] The traction substation is the first traction substation or the second traction substation of the bilateral fully parallel direct-supply traction network. If the traction substation is the first traction substation, the parallel line BL is the parallel line from the first traction substation to the SP section of the substation. If the traction substation is the second traction substation, the parallel line BL is the parallel line from the second traction substation to the SP section of the substation.
[0018] Further, such as and The fault point is located on the downfeeder from the traction substation to the parallel line BL; and The fault point is located on the upfeeder from the traction substation to the parallel line BL; and The fault point is located on the downlink feeder from the parallel line BL to the substation SP; and The fault point is located on the uplink feeder from the parallel line BL to the substation SP.
[0019] The beneficial effects of the present invention are that it can complete the fault distance measurement of the bilateral full-parallel direct-supply traction network, and can also identify the fault section and the fault line type, accurately determine the fault, and is conducive to the fault handling and operation inspection and maintenance of electrified railways. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1Schematic diagram of the overall structure of the bilateral fully parallel direct supply traction network.
[0021] Figure 2 Schematic diagram of the current path when the fault is located in the SS-1-BL interval.
[0022] Figure 3 Schematic diagram of the current path when the fault is located in the BL-SP interval.
[0023] Figure 4 Schematic diagram of the current path when the fault is located on the parallel line BL.
[0024] Figure 5 Schematic diagram of the fault circuit of the downlink line in the SS1-BL section.
[0025] Figure 6 Schematic diagram of the fault loop of the upstream line in the SS1-BL section.
[0026] Figure 7 Schematic diagram of the fault circuit of the downlink line in the BL-SP section.
[0027] Figure 8 Schematic diagram of the fault loop of the upstream line in the BL-SP section.
[0028] Fig. 9 Flow chart of fault location technology for bilateral fully parallel direct supply traction network. DETAILED DESCRIPTION
[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.
[0030] The structure of the traction network with bilateral full parallel direct supply is as follows Figure 1 As shown in the figure, when the substation SP contact switch is in the closed state, the traction network forms a bilateral power supply form, and the power supply arm between the traction substation SS-1 and the traction substation SS-2 is the same phase voltage, which directly supplies power to the up and down double-track traction network. During the operation of the locomotive, it draws power from two adjacent traction substations at the same time. The traction network forms a parallel connection through the up and down feeder circuit breakers of the substation SP. Furthermore, a parallel line BL is added between the traction substation and the substation, and the up and down traction networks form a full parallel relationship.
[0031] The section from traction substation SS-1 to substation SP is structurally symmetrical with the section from substation SP to traction substation SS-2. The principle of fault distance measurement in this method is explained below using the section from traction substation SS-1 to substation SP as an example. The distance measurement principle from substation SP to traction substation SS-2 is similar.
[0032] Figure 2-Figure 8In the above, it is assumed that the power supply on both sides is symmetrical and equal, and is respectively attributed to the traction substation SS-1 and the substation SP, and the parameters of the upstream and downstream traction network lines are symmetrically and evenly distributed.
[0033] Figure 2-Figure 8 In the figure, QF1 and QF2 are the downlink and uplink feeder circuit breakers of traction substation SS-1, respectively, and QF3 and QF4 are the downlink and uplink feeder circuit breakers of the power supply arm of substation SP pointing to traction substation SS-1, respectively. CT1, CT2, CT3 and CT4 correspond to the current transformers at circuit breakers QF1, QF2, QF3 and QF4, respectively, and the measured currents are and
[0034] When a short-circuit fault occurs, the fault interval judgment conditions can be determined based on the distribution characteristics of the SS-1 feeder current of the traction substation.
[0035] like Figure 2 As shown in the figure, when the fault point is between the traction substation SS-1 and the parallel line BL, whether the fault point occurs in the downstream or upstream traction network, the current and One of the two sides must be connected to the fault point through the parallel line BL, while the other side of the current is directly supplied to the fault point. If the fault is established, the fault is located between traction substation SS-1 and parallel line BL.
[0036] like Figure 3 As shown in the figure, when the fault point is between the parallel line BL and the substation SP, the current and All of them are supplied to the fault point through the parallel line BL. Compared with the traction network, the impedance of the parallel line BL can be approximately ignored. Whether the fault point occurs in the downstream or upstream traction network, the current and One of the two sides must be connected to the fault point through the parallel line BL, while the other side of the current is directly supplied to the fault point. If the fault is established, the fault is located in the section from the parallel line BL to the substation SP.
[0037] like Figure 4 As shown in the figure, when the fault is located on the parallel line BL, the currents at both ends are directly supplied to the fault point through the traction network, and the currents of the traction substation SS-1 and the substation SP meet the following characteristics at the same time: and
[0038] The methods for fault distance measurement and determination of fault interval and line type are as follows:
[0039] 1. When the fault is between traction substation SS-1 and parallel line BL, the equivalent power sources on both sides will provide short-circuit current to the fault point through the up and down traction networks. The section length from traction substation SS-1 to parallel line BL is D1, and the section length from parallel line BL to substation SP is D2.
[0040] Since the parallel line BL is not equipped with a current transformer, the measured current at the parallel line BL cannot be obtained. Considering the parallel line BL as a loop section, as shown in formula (1), the current flowing into the parallel line BL section from the upfeeder and downfeeder of the partition SP is equal to the current of the parallel line BL section and the current And supply to the fault point.
[0041]
[0042] For the fault between traction substation SS-1 and parallel line BL, the distance x from traction substation SS-1 to the fault point satisfies the following formula:
[0043]
[0044] In the formula, Right now Pick The smaller value.
[0045] like Figure 5 As shown in Figure 2, when the downlink line fails, The power is supplied to the fault point through the parallel line BL, satisfying the following conditions:
[0046]
[0047] therefore, Pick Substituting into formula (2), the distance from the fault point to the traction substation SS-1 can be calculated, and formula (3) can determine that the fault point is located on the downlink line.
[0048] like Figure 6 As shown in Figure 2, when the uplink fails, The power is supplied to the fault point through the parallel line BL, satisfying the following conditions:
[0049]
[0050] therefore, Pick Substituting into formula (2), the distance from the fault point to the traction substation SS-1 can be calculated, and formula (4) can determine that the fault point is located on the up line.
[0051] 2. When the fault is located between the parallel line BL and the substation SP, the equivalent power sources on both sides still provide short-circuit current to the fault point through the upstream and downstream traction networks, but the current flow path changes.
[0052] At this time, the cross section and current of the parallel line BL It is equal to the sum of the current of the up-feeder and down-feeder of traction substation SS-1, and supplies the fault point with the sum of the current of the parallel line BL section. Calculated by formula (5).
[0053]
[0054] For a fault in the section from the parallel line BL to the substation SP, the distance x from the fault point to the traction substation SS-1 satisfies the following formula:
[0055]
[0056] In the formula,
[0057] like Figure 7 As shown in Figure 2, when the downlink line fails, The power is supplied to the fault point through the parallel line BL, satisfying the following conditions:
[0058]
[0059] Therefore, equation (7) can determine that the fault point is located on the downlink line.
[0060] like Figure 8 As shown in Figure 2, when the uplink fails, The power is supplied to the fault point through the parallel line BL, satisfying the following conditions:
[0061]
[0062] Therefore, equation (8) can determine that the fault point is located on the uplink line.
[0063] 3. When the fault is located at the parallel line BL, and Any of the above methods is applicable to the fault distance calculation in this case. When using formula (2) for calculation, Desirable or Perform calculations.
[0064] Since the length of the section from the traction substation SS-1 to the parallel line BL is D1, when the fault is located at the parallel line BL, it can be considered that the distance x from the fault point to the traction substation SS-1 is D1.
[0065] Embodiment 1:
[0066] A fault location method for a bilateral full parallel direct supply traction network, wherein a fault occurs in the traction network in the section from traction substation SS-1 to substation SP, comprising the following steps:
[0067] Step 1: Measure and collect the current of the downstream feeder line of SS-1 of the traction substation and upstream feeder current Measure and collect the downfeeder current from the SP substation to the SS-1 power supply arm of the traction substation and upstream feeder current
[0068] Step 2: Determine the fault range: Is it equal to
[0069] like If the fault is located between SS-1 and BL, go to step ③;
[0070] like Go to step ⑦.
[0071] Step 3: When the fault is located between SS-1 and BL, the distance x from the fault point to the traction substation SS-1 satisfies the following calculation expression:
[0072]
[0073] in, is the cross section and current of the parallel line BL, which is equal to the downstream feed current of the sub-area SP and upstream feeder current The sum of ; D1 is the distance from traction substation SS-1 to parallel line BL; for The sum of For value selection, see subsequent steps ⑤ and ⑥.
[0074] Step ④: Determine the fault type.
[0075] like If the downlink traction network fails, go to step ⑤;
[0076] like If the upstream traction network fails, go to step ⑥.
[0077] Step ⑤: Downlink traction network fault distance calculation.
[0078] Step ③ Pick Substitute it into the distance measurement calculation formula to calculate the distance x from the fault point to the traction substation SS-1.
[0079] Step ⑥: Upstream traction network fault distance measurement calculation.
[0080] Step ③ Pick Substitute it into the distance measurement calculation formula to calculate the distance x from the fault point to the traction substation SS-1.
[0081] Step 7: Determine the fault range: Is it equal to
[0082] like If the fault is located between BL and SP, go to step ⑧;
[0083] like If the fault is located at BL, go to step ⑩.
[0084] Step ⑧: When the fault is located between BL and SP, the distance x from the fault point to the traction substation SS-1 satisfies the following calculation expression:
[0085]
[0086] in, is the cross section and current of the parallel line BL, which is equal to the downstream feed current of traction substation SS-1 and upstream feeder current D2 is the distance from the parallel line BL to the partition SP; for The sum of .
[0087] Step 9: Determine the fault type.
[0088] like It is a downlink traction network failure; if It is an uplink traction network failure.
[0089] Step ⑩: The fault is located at BL. The calculation expressions in steps ③ and ⑧ can be used to calculate the distance x from the fault point to the traction substation SS-1 in this case. When the calculation expression in step ③ is used, Desirable or Perform calculations.
[0090] Embodiment 2:
[0091] A fault location method for a bilateral fully parallel direct-supply traction network, in which a fault occurs in the traction network in the section from traction substation SS-2 to substation SP.
[0092] This embodiment is different from Embodiment 1 in the following aspects:
[0093] Measuring and collecting the current of the SS-2 downstream feeder of the traction substation and upstream feeder current Measure and collect the downfeeder current from the SP substation to the SS-2 power supply arm of the traction substation and upstream feeder current The length of the section from traction substation SS-2 to parallel line BL is D1, and the length of the section from parallel line BL to substation SP is D2; the measured distance x is the distance from the fault point to traction substation SS-2.
[0094] The other steps are the same as those in Example 1 and will not be described in detail.
Claims
1. A fault distance measurement method for a bilateral full parallel direct supply traction network, characterized in that: The fault is a short circuit fault in the SP section from the traction substation to the substation, including: Measuring the downstream feeder current of traction substation and upstream feeder current Measuring the downstream feeder current from the substation SP to the traction substation and upstream feeder current like and The distance from the fault point to the traction substation is like and The distance from the fault point to the traction substation is like and The fault point is located on the parallel line BL, and the distance from the fault point to the traction substation is x=D1; like and The distance from the fault point to the traction substation is Wherein, D1 is the distance from the traction substation to the parallel line BL, and D2 is the distance from the parallel line BL to the substation SP; The traction substation is the first traction substation or the second traction substation of the bilateral fully parallel direct-supply traction network. If the traction substation is the first traction substation, the parallel line BL is the parallel line from the first traction substation to the SP section of the substation. If the traction substation is the second traction substation, the parallel line BL is the parallel line from the second traction substation to the SP section of the substation.
2. The fault location method for a bilateral full parallel direct supply traction network according to claim 1, characterized in that: like and Then the fault point is located on the downfeeder from the traction substation to the parallel line BL; like and Then the fault point is located on the up-feeder from the traction substation to the parallel line BL; like and Then the fault point is located on the downfeeder from the parallel line BL to the substation SP; like and The fault point is located on the uplink feeder from the parallel line BL to the substation SP.