Traction power supply feeder current increment protection method and system

Abstract

The invention discloses a traction power supply feeder current increment protection method and system. The method comprises the following steps: acquiring a field working condition to carry out wave recording; acquiring sampling current value conditions corresponding to load changes of the locomotive under various working conditions through wave recording, and performing harmonic analysis, current variation analysis and angle analysis on the current value to inquire load characteristic quantity so as to obtain an analysis result; and forming a corresponding protection scheme according to an analysis result. According to the method, the analysis result is obtained by analyzing the field data, the corresponding protection scheme is generated according to the analysis result, and misoperation and data of current increment protection are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electrified railway traction power supply, and in particular to a traction power supply feeder current increment protection method and system. Background Art

[0002] The high-resistance protection of the high-speed railway traction network is mainly achieved by comparing the difference between the power frequency one-cycle current increment during traction network fault and normal operation, that is, current increment protection. Due to the lack of research on the maximum value of the power frequency one-cycle current increment of the traction network load current and the minimum current of high-resistance grounding, there are many cases of false operation and refusal of current increment protection in actual operation. Summary of the invention

[0003] The object of the present invention is to provide a traction power supply feeder current incremental protection method and system, by analyzing the field data to obtain the analysis results, generate a corresponding protection scheme according to the analysis results, and reduce the false operation and refusal of the current incremental protection.

[0004] The present invention is achieved through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a traction power supply feeder current increment protection method, comprising:

[0006] Obtain on-site working conditions through wave recording;

[0007] According to the sampling current values ​​corresponding to the load changes of the locomotive under various working conditions obtained by recording, the current values ​​are subjected to harmonic analysis, current change analysis and angle analysis to query the load characteristic quantity and obtain the analysis results;

[0008] A corresponding protection plan is formed based on the analysis results.

[0009] In a second aspect, an embodiment of the present invention provides a traction power supply feeder current increment protection system, comprising: a data acquisition module, a data analysis module and a solution generation module, wherein the data acquisition module is used to acquire on-site working conditions by recording;

[0010] The data analysis module is used to obtain the sampled current values ​​corresponding to the load changes of the locomotive under various working conditions through wave recording, perform harmonic analysis, current change analysis and angle analysis on the current value to query the load characteristic quantity and obtain the analysis result;

[0011] The solution generation module is used to generate a corresponding protection solution according to the analysis result.

[0012] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0013] A traction power supply feeder current incremental protection method and system provided in an embodiment of the present invention analyzes field data to obtain analysis results, generates corresponding protection schemes according to the analysis results, and reduces false operation and refusal of current incremental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0015] Figure 1 A flow chart of a traction power supply feeder current increment protection method provided by the first embodiment of the present invention;

[0016] Figure 2 This is the waveform diagram collected by the series protection device;

[0017] Figure 3 This is a schematic diagram of the section insulator of the Xiaguanying switch station;

[0018] Figure 4 This is the waveform diagram when the current entering the power supply arm changes suddenly when the locomotive passes through the section;

[0019] Figure 5 Flow chart for determining the cause of incremental protection for determining the incremental current of the transferred load;

[0020] Figure 6 Flow chart of the protection scheme for the case where the incremental protection caused by high-resistance grounding and load is difficult to distinguish;

[0021] Figure 7 A structural block diagram of a traction power supply feeder current incremental protection system provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0023] Example 1

[0024] like Figure 1 As shown, a traction power supply feeder current increment protection method provided by the first embodiment of the present invention comprises the following steps:

[0025] Obtain on-site working conditions through wave recording;

[0026] According to the sampling current values ​​corresponding to the load changes of the locomotive under various working conditions obtained by recording, the current values ​​are subjected to harmonic analysis, current change analysis and angle analysis to query the load characteristic quantity and obtain the analysis results;

[0027] A corresponding protection plan is formed based on the analysis results.

[0028] In order to solve the technical problems existing in the prior art, the tripping data analysis is carried out for the current incremental protection: the sensitivity and characteristic quantity analysis of the feeder incremental protection is completed through the tripping data of the feeder protection measurement and control device and the main transformer over-level tripping in the past five years, and the sensitivity is further improved through the characteristic quantity. The fault and non-fault tripping characteristic difference analysis is completed through the fault tripping and non-fault tripping data of the feeder protection measurement and control device, and the fault or non-fault tripping is identified through the relevant characteristic quantity. By recording the representative working conditions on site, the corresponding sampling current value of the load change under various working conditions of the locomotive (locomotive start-up, load transfer, over-phase, reverse power transmission, etc.) is obtained, and the load characteristic quantity is queried by performing harmonic analysis, current change analysis, and angle analysis on the current sampling value to obtain the analysis results. The analysis results include: the incremental misoperation caused by the locomotive over-phase surge current and the incremental misoperation caused by the locomotive over-segmentation and the incremental protection caused by high-resistance grounding and load are not easy to distinguish.

[0029] When the locomotive is over-phased, a surge current will be generated. The typical waveform is shown in the waveform collected by the series protection device. Figure 2 shown.

[0030] according to Figure 2 The data collected shows that the increment of inrush current is 1.128*320=360.96A, but the second harmonic is very large, which can generally be used for blocking. However, when the traction load current is superimposed with the excessive phase inrush current, due to the large fundamental current, the second harmonic generated by the excessive phase inrush current may be difficult to reach the blocking value, and the high-resistance protection may malfunction.

[0031] The specific method of generating the corresponding protection scheme based on the above analysis results is: using waveform recognition technology, based on the waveform symmetry principle algorithm, continuously comparing whether the sampling points of half a cycle meet the waveform symmetry criterion, and then distinguishing between excitation inrush current and fault current. For excitation inrush current, locking incremental protection is used.

[0032] When the locomotive passes through the section insulator, the load current will be diverted, and the power supply arm in the driving direction will generate a corresponding incremental current. Figure 3 When the locomotive passes through the section, the current of the power supply arm entering the section suddenly changes, as shown in the waveform diagram. Figure 4 shown.

[0033] The current suddenly changes from 0 to 1.856*250=464A, and the second harmonic content is lower than the set value. The incremental action caused by this load diversion can only be solved by raising the set value of the current increment, which is generally set to 450A.

[0034] The protection scheme obtained according to the above analysis results is as follows: the two feeder protection devices on both sides of the sectioner collect the current on this side and the opposite side at the same time. After the incremental protection on this side is started, the incremental current of the transferred load is used to determine whether the incremental protection is caused by the transferred load or the fault. If it is caused by the transferred load, the incremental protection is locked.

[0035] The calculation method of the transfer load incremental current is as follows:

[0036] Transfer load incremental current = incremental current + opposite side current incremental value;

[0037] The opposite side current increment value = the opposite side current – ​​the opposite side current of the first two cycles when the incremental element is started.

[0038] like Figure 5 As shown, the incremental protection is judged by the transfer load incremental current whether it is caused by the transfer load or the fault. If it is caused by the transfer load, the incremental protection is locked. The specific method includes:

[0039] The incremental blocking criterion starts timing;

[0040] Determine whether the set load transfer power determination time has been reached;

[0041] If yes, then incremental protection is performed;

[0042] If not, determine whether the incremental current of the transferred load is greater than the incremental protection setting;

[0043] If it is less than the incremental protection setting, the blocking incremental protection element will be activated and the incremental protection will be blocked;

[0044] If it is greater than the incremental protection setting, the locking incremental protection element will not operate, the incremental locking criterion will end, and the incremental protection will be opened.

[0045] Specifically, the incremental protection starts timing after it is started until the "transfer load current judgment time". If the transfer load incremental current is less than the incremental protection setting value during this time period, the lockout incremental protection element will be actuated; if the lockout continues until the "transfer load current judgment time" timing ends, the lockout incremental protection element will return;

[0046] If the incremental current of the transferred load during this time period is greater than the incremental protection setting, the incremental protection will not be locked and this criterion will be directly opened. The incremental protection can operate normally and no repeated judgment will be made during this time period.

[0047] Comparing the waveform of load shunting with the increment of actual high-resistance grounding, the second harmonic content is relatively small, and both have a certain DC component. It is difficult to distinguish between faults and loads from the waveform characteristics. The waveform voltage of actual high-resistance grounding has a distortion rate, but it is currently difficult to distinguish the two from waveform analysis. The angle of actual high-resistance grounding is generally around 10°, while the fault report of load shunting is generally around 0°.

[0048] like Figure 6 As shown in the figure, the protection scheme for the incremental protection caused by high-resistance grounding and load is difficult to distinguish: after the current increment is started, the impedance angle is used for blocking. If the angle is in the load angle range or the inrush angle range and the protection current is less than the overcurrent setting value, the blocking current increment will not be exported. If the PT is disconnected, the angle criterion is not used.

[0049] A traction power supply feeder current incremental protection method provided in an embodiment of the present invention analyzes field data to obtain analysis results, generates a corresponding protection scheme based on the analysis results, and reduces false operation and refusal of current incremental protection.

[0050] Example 2

[0051] like Figure 7 As shown, another embodiment of the present invention provides a traction power supply feeder current incremental protection system, including: a data acquisition module, a data analysis module and a scheme generation module, the data acquisition module is used to obtain the on-site working conditions through recording; the data analysis module is used to obtain the corresponding sampled current values ​​of the load changes of the locomotive under various working conditions through recording, perform harmonic analysis, current change analysis and angle analysis on the current value to query the load characteristic quantity, and obtain the analysis result; the scheme generation module is used to generate a corresponding protection scheme according to the analysis result.

[0052] The scheme generation module includes a first scheme generation unit. When the analysis result is that the incremental malfunction is caused by excessive phase surge current of the locomotive, the first scheme generation unit adopts a waveform symmetry principle algorithm to continuously compare whether half a cycle sampling points meet the waveform symmetry criterion, distinguish between excitation surge current and fault current, and adopt locked incremental protection for the excitation surge current.

[0053] The scheme generation module includes a second scheme generation unit. When the analysis result of the second generation unit is an incremental malfunction caused by the locomotive passing through a section, the two feeder protection devices on both sides of the sectioner of the second generation unit respectively collect the current on this side and the opposite side, and the incremental protection on this side is started. The incremental current of the transferred load is used to determine whether the incremental protection is caused by the transferred load or a fault. If it is caused by the transferred load, the locked incremental protection is adopted.

[0054] The specific calculation method of the transfer load incremental current is:

[0055] Transfer load incremental current = incremental current + opposite side current incremental value;

[0056] The opposite side current increment value = the opposite side current – ​​the opposite side current of the first two cycles when the incremental element is started.

[0057] In the second scheme generating unit, the incremental protection is judged by the incremental current of the transferred load whether it is caused by the transferred load or the fault. If it is caused by the transferred load, the specific method of adopting the locking incremental protection includes:

[0058] The incremental blocking criterion starts timing;

[0059] Determine whether the set load transfer power determination time has been reached;

[0060] If yes, then incremental protection is performed;

[0061] If not, determine whether the incremental current of the transferred load is greater than the incremental protection setting;

[0062] If it is greater than the incremental protection setting, the locking incremental protection element will not operate, the incremental locking criterion will end, and the incremental protection will be opened;

[0063] If it is less than the incremental protection setting, the locking incremental protection element will be activated and the incremental protection will be locked.

[0064] A traction power supply feeder current incremental protection system provided in an embodiment of the present invention analyzes field data to obtain analysis results, generates corresponding protection schemes according to the analysis results, and reduces false operation and refusal of current incremental protection.

[0065] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A traction power supply feeder current increment protection method, characterized in that: include: Obtain on-site working conditions through wave recording; According to the sampling current values ​​corresponding to the load changes of the locomotive under various working conditions obtained by recording, the current values ​​are subjected to harmonic analysis, current change analysis and angle analysis to query the load characteristic quantity and obtain the analysis results; A corresponding protection plan is formed based on the analysis results.

2. The method according to claim 1, characterized in that The analysis result includes: incremental malfunction caused by excessive phase surge current of the locomotive, and the specific method of forming a corresponding protection scheme according to the analysis result includes: The waveform symmetry principle algorithm is adopted to continuously compare whether the half-cycle sampling points meet the waveform symmetry criterion, distinguish the excitation inrush current from the fault current, and adopt the locking incremental protection for the excitation inrush current.

3. The method according to claim 1, characterized in that The analysis result also includes: incremental misoperation caused by the locomotive passing through the segment. The specific method of forming a corresponding protection scheme according to the analysis result includes: The two feeder protection devices on both sides of the sectionalizer collect the current on the local side and the opposite side respectively; The incremental protection on this side is started, and the incremental current of the transferred load is used to determine whether the incremental protection is caused by the transferred load or the fault. If it is caused by the transferred load, the locked incremental protection is used.

4. The method according to claim 3, characterized in that The specific calculation method of the transfer load incremental current is: Transfer load incremental current = incremental current + opposite side current incremental value; The opposite side current increment value = the opposite side current – ​​the opposite side current of the first two cycles when the incremental element is started.

5. The method according to claim 4, characterized in that The specific method of judging whether the incremental protection is caused by the transferred load or the fault by the transferred load incremental current and adopting the locking incremental protection if it is caused by the transferred load includes: The incremental blocking criterion starts timing; Determine whether the set load transfer power determination time has been reached; If yes, then incremental protection is performed; If not, determine whether the incremental current of the transferred load is greater than the incremental protection setting; If it is less than the incremental protection setting, the locking incremental protection element will be activated and the incremental protection will be locked; If it is greater than the incremental protection setting, the locking incremental protection element will not operate, the incremental locking criterion will end, and the incremental protection will be opened.

6. A traction power supply feeder current increment protection system, characterized in that: include: A data acquisition module, a data analysis module and a solution generation module, wherein the data acquisition module is used to acquire the on-site working conditions through wave recording; The data analysis module is used to obtain the sampled current values ​​corresponding to the load changes of the locomotive under various working conditions through wave recording, perform harmonic analysis, current change analysis and angle analysis on the current value to query the load characteristic quantity and obtain the analysis result; The solution generation module is used to generate a corresponding protection solution according to the analysis result.

7. The system according to claim 6, characterized in that The scheme generation module includes a first scheme generation unit. When the analysis result is that the incremental malfunction is caused by excessive phase surge current of the locomotive, the first scheme generation unit adopts a waveform symmetry principle algorithm to continuously compare whether half a cycle sampling points meet the waveform symmetry criterion, distinguish between excitation surge current and fault current, and adopt locked incremental protection for the excitation surge current.

8. The system according to claim 6, characterized in that The scheme generation module includes a second scheme generation unit. When the analysis result of the second generation unit is an incremental malfunction caused by the locomotive passing through the section, the two feeder protection devices on both sides of the sectioner of the second generation unit respectively collect the current on this side and the opposite side, and the incremental protection on this side is started. The incremental current of the transferred load is used to determine whether the incremental protection is caused by the transferred load or the fault. If it is caused by the transferred load, the locked incremental protection is adopted.

9. The system according to claim 8, characterized in that The specific calculation method of the transfer load incremental current is: Transfer load incremental current = incremental current + opposite side current incremental value; The opposite side current increment value = the opposite side current – ​​the opposite side current of the first two cycles when the incremental element is started.

10. The system according to claim 9, characterized in that The specific method of determining whether the incremental protection is caused by the transferred load or the fault by the transferred load incremental current in the second scheme generating unit and adopting the blocking incremental protection if it is caused by the transferred load includes: The incremental blocking criterion starts timing; Determine whether the set load transfer power determination time has been reached; If yes, then incremental protection is performed; If not, determine whether the incremental current of the transferred load is greater than the incremental protection setting; If it is less than the incremental protection setting, the locking incremental protection element will be activated and the incremental protection will be locked; If it is greater than the incremental protection setting, the locking incremental protection element will not operate, the incremental locking criterion will end, and the incremental protection will be opened.

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