CN114002553A - Traction power supply 27.5kV cable joint fault identification method - Google Patents
Traction power supply 27.5kV cable joint fault identification method Download PDFInfo
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- 238000012423 maintenance Methods 0.000 abstract description 3
- 238000004088 simulation Methods 0.000 description 8
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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Abstract
The invention discloses a method for identifying a fault of a traction power supply 27.5kV cable joint, which comprises the following steps: current signals on two sides of the connector are respectively acquired in real time for S cable connectors, after the detected current signals are filtered, the two currents are differenced, and if the current difference value of the current nth cable connector is larger than a setting threshold value delta i at continuous W pointssetIf not, judging that the nth cable joint has no fault, and sending the serial number of the cable joint and the state information of whether the cable is in fault to the traction substation terminal by the fault detection device. The invention can quickly identify the cable joint fault of the traction power supply system, thereby improving the safety and the economy of the power supply of the traction power supply system, and effectively reducing the power failure time and the maintenance and search time of the electrified railway.
Description
Technical Field
The invention belongs to the technology of cable fault detection of a traction power supply system, and particularly relates to a method for identifying a fault of a traction power supply 27.5kV cable joint.
Background
The 27.5kV cable of the electrified railway is directly buried underground or laid along a cable trench, the running environment is poor, power supply load points along the line are numerous, and a power cable line is divided into a plurality of sections, so that the cable branch joints are frequently used and numerous, and the cable joints become weak links of the 27.5kV cable. Furthermore, as the operating time and load of the power cable increases, the failure of the power cable becomes more and more frequent. Because the cable line is buried underground, the fault point can not be directly found through an intuitive method during the fault, and if the fault point cannot be determined in time and the power supply is recovered, extra power failure loss is brought. Therefore, the method has very important significance for carrying out online information acquisition and monitoring on the cable joint and quickly positioning and researching after a fault occurs, shortening the fault repairing time, recovering power supply as soon as possible and ensuring uninterrupted safe operation of a railway system.
At present, the method of trying to close the telemechanical switch or the isolating switch one by one and then walking to find the fault position in the railway 27.5kV cable has the defect that the method cannot be avoided:
(1) the pull-close switch has great blindness in finding a fault section. The non-electric telecontrol section is pulled and closed manually, which wastes time and labor; although the telecontrol section can be used for switching on and off the switch by telecontrol, the fault section is judged by means of section-by-section trial transmission, a certain time is needed, and the disadvantage is that the section-by-section trial transmission enables system power equipment to bear fault heavy current impact for many times, the equipment is easily damaged, if the heavy current impact can reduce the service life of the voltage regulator, the voltage regulator is burned out when the voltage regulator is serious, and the loss is serious.
(2) The method is used for searching for the tripping caused by unknown reasons due to soft faults or transient faults, and at present, the large sea fishing needle type searching can be carried out only within the range of one power supply arm (10-20 kS) by manpower, so that fault points are difficult to find, and hidden dangers are difficult to eliminate.
Disclosure of Invention
The method provides a rapid identification technology for the cable joint fault of the traction power supply system, thereby improving the safety and the economy of the power supply of the traction power supply system, and effectively reducing the power failure time and the maintenance and search time of the electrified railway. The invention provides a method for identifying a fault of a traction power supply 27.5kV cable joint.
The invention discloses a method for identifying a fault of a traction power supply 27.5kV cable joint, which comprises the following steps of:
step 1: and acquiring data of the cable joint.
Numbering S cable joints in a traction power supply 27.5kV cable, numbering the S cable joints from the top of the cable as 1,2,3, … and S, and collecting current signals on two sides of each cable joint in real time at a sampling frequency of 10 kHz; time k, right of each cable jointThe side-collected current is iR1(k)、iR2(k)、iR3(k)、…、iRS(k) The current collected at the left side of each cable joint is iL1(k)、iL2(k)、iL3(k)、…、iLS(k)。
Step 2: and (5) processing the current signal.
S21: will iR1(k)、iR2(k)、iR3(k)、…、iRS(k) Filtering to obtain processed current iR1′(k)、iR2′(k)、iR3′(k)、…、iRS' (k); will iL1(k)、iL2(k)、iL3(k)、…、iLS(k) Filtering to obtain processed current iL1′(k)、iL2′(k)、iL3′(k)、…、iLS′(k)。
S22: subtracting the current signals on the left side and the right side of the cable joint after filtering processing to obtain the current difference value delta i of each cable joint1(k)、Δi2(k)、Δi3(k)、…、ΔiS(k)。
And step 3: and identifying the fault of the cable joint.
S31: the current difference Δ i for each cable joint to be calculated1(k)、Δi2(k)、Δi3(k)、…、ΔiS(k) And a threshold value Δ isetComparing the current difference value delta i of the nth cable jointn(k)>ΔisetWhether or not, wherein n is 1,2,3, …, S; if yes, continuously judging the current difference value delta i of continuous W sampling points from the nth cable jointn+1(k)、Δin+2(k)、…、Δin+W(k) Whether or not it is greater than threshold Δ isetIf the current state is still met, judging that the nth cable joint has a fault; otherwise, judging that the nth cable joint has no fault.
S32: and wirelessly transmitting the judged fault or non-fault information of the nth cable joint to a traction substation terminal through GPRS (general packet radio service), and receiving the serial number information of the S cable joints and the information of whether the fault exists by the traction substation terminal.
Further, the threshold value Δ isetTake 0.02pu, where pu is the per unit value of the cable current.
Further, the number W of consecutive sampling points is taken to be 5.
The beneficial technical effects of the invention are as follows:
(1) a high resistance ground fault of the cable joint can be identified. The conventional cable fault detection generally focuses on the whole cable line, the high-resistance ground fault cannot be identified due to weak electrical characteristics when the high-resistance ground fault occurs, and meanwhile, the cable joint is a weak link of the whole cable line due to numerous cable branches, partial discharge is easy to occur to the cable joint, and the fault rate is high, so that the cable joint fault can be accurately identified by utilizing the electrical quantity information on two sides of the cable joint.
(2) The cable joint position and the state information of whether the cable joint is in fault or not can be visually displayed in real time. The invention sends the information whether each cable joint is in fault or not to the traction substation terminal, and the traction substation terminal receives the cable number information and the information whether the cable joint is in fault or not so as to allow operation and maintenance staff to visually monitor the state of the cable joint.
Drawings
FIG. 1 is a flow chart of a method for identifying a fault of a traction power supply 27.5kV cable joint.
Fig. 2 is a three-phase current waveform of a cable connector No. 3 in a working condition 1 in a simulation experiment of the invention.
Fig. 3 is a three-phase current waveform of a cable joint No. 5 in a working condition 2 in a simulation experiment of the invention.
Fig. 4 is a three-phase current waveform of the cable joint No. 6 in the working condition 3 in the simulation experiment of the invention.
Fig. 5 is an enlarged view of the C-phase current waveform of the cable joint No. 6 in the working condition 3 in the simulation experiment of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to specific embodiments and simulation experiments.
The invention discloses a method for identifying a fault of a traction power supply 27.5kV cable joint, which is shown in figure 1 and comprises the following steps:
step 1: and acquiring data of the cable joint.
Numbering S cable joints in a traction power supply 27.5kV cable, numbering the S cable joints from the top of the cable as 1,2,3, … and S, and collecting current signals on two sides of each cable joint in real time at a sampling frequency of 10 kHz; at the moment k, the current collected at the right side of each cable joint is iR1(k)、iR2(k)、iR3(k)、…、iRS(k) The current collected at the left side of each cable joint is iL1(k)、iL2(k)、iL3(k)、…、iLS(k)。
Step 2: and (5) processing the current signal.
S21: will iR1(k)、iR2(k)、iR3(k)、…、iRS(k) Filtering to obtain processed current iR1′(k)、iR2′(k)、iR3′(k)、…、iRS' (k); will iL1(k)、iL2(k)、iL3(k)、…、iLS(k) Filtering to obtain processed current iL1′(k)、iL2′(k)、iL3′(k)、…、iLS′(k)。
S22: subtracting the current signals on the left side and the right side of the cable joint after filtering processing to obtain the current difference value delta i of each cable joint1(k)、Δi2(k)、Δi3(k)、…、ΔiS(k)。
And step 3: and identifying the fault of the cable joint.
S31: the current difference Δ i for each cable joint to be calculated1(k)、Δi2(k)、Δi3(k)、…、ΔiS(k) And a threshold value Δ iset(threshold value Δ i)set0.02pu is taken as the per unit value of the cable current), and the current difference value delta i of the nth cable joint is judgedn(k)>ΔisetWhether or not, wherein n is 1,2,3, …, S; if yes, continuously judging the current difference value delta i of continuous W (preferably, W is 5) sampling points from the nth cable jointn+1(k)、Δin+2(k)、…、Δin+W(k) Whether or not it is greater than threshold Δ isetIf the current state is still met, judging that the nth cable joint has a fault; otherwise, it is determinedThe nth cable joint did not fail.
S32: and wirelessly transmitting the judged fault or non-fault information of the nth cable joint to a traction substation terminal through GPRS (general packet radio service), and receiving the serial number information of the S cable joints and the information of whether the fault exists by the traction substation terminal.
Simulation experiment
In order to verify the identification method, a simulation model of a traction power supply 27.5kV cable is built in PSCAD/ESTDC.
Three working conditions are simulated on a simulation model of a traction power supply 27.5kV cable:
working condition 1: and an AB two-phase short circuit fault occurs in the No. 3 cable joint, and the three-phase current waveform is shown in figure 2.
Working condition 2: the phase-a metallic ground fault occurs at cable joint No. 5, and the waveform of the three-phase current is shown in fig. 3.
Working condition 3: the cable joint No. 6 has a 30 ohm transition resistance earth fault of the C phase, and the three-phase current waveform is shown in figure 4, wherein the C phase current waveform is shown in figure 5.
The current difference values of five continuous sampling points under three working conditions are all larger than a threshold value delta isetThe provided fault identification method can accurately identify different types of faults of the traction power supply 27.5kV cable head.
Claims (3)
1. A method for identifying a fault of a traction power supply 27.5kV cable joint is characterized by comprising the following steps:
step 1: cable joint data acquisition
Numbering S cable joints in a traction power supply 27.5kV cable, numbering the S cable joints from the top of the cable as 1,2,3, … and S, and collecting current signals on two sides of each cable joint in real time at a sampling frequency of 10 kHz; at the moment k, the current collected at the right side of each cable joint is iR1(k)、iR2(k)、iR3(k)、…、iRS(k) The current collected at the left side of each cable joint is iL1(k)、iL2(k)、iL3(k)、…、iLS(k)；
Step 2: current signal processing
S21: will iR1(k)、iR2(k)、iR3(k)、…、iRS(k) Filtering to obtain processed current iR1′(k)、iR2′(k)、iR3′(k)、…、iRS' (k); will iL1(k)、iL2(k)、iL3(k)、…、iLS(k) Filtering to obtain processed current iL1′(k)、iL2′(k)、iL3′(k)、…、iLS′(k)；
S22: subtracting the current signals on the left side and the right side of the cable joint after filtering processing to obtain the current difference value delta i of each cable joint1(k)、Δi2(k)、Δi3(k)、…、ΔiS(k)；
And step 3: cable joint fault identification
S31: the current difference Δ i for each cable joint to be calculated1(k)、Δi2(k)、Δi3(k)、…、Δim(k) And a threshold value Δ isetComparing the current difference value delta i of the nth cable jointn(k)>ΔisetWhether or not, wherein n is 1,2,3, …, S; if yes, continuously judging the current difference value delta i of continuous W sampling points from the nth cable jointn+1(k)、Δin+2(k)、…、Δin+W(k) Whether or not it is greater than threshold Δ isetIf the current state is still met, judging that the nth cable joint has a fault; otherwise, judging that the nth cable joint has no fault;
s32: and wirelessly transmitting the judged fault or non-fault information of the nth cable joint to a traction substation terminal through GPRS (general packet radio service), and receiving the serial number information of the S cable joints and the information of whether the fault exists by the traction substation terminal.
2. The method for identifying the fault of the cable joint powered by traction and supplying 27.5kV according to claim 1, wherein the threshold value delta isetTake 0.02pu, where pu is the per unit value of the cable current.
3. The method for identifying the fault of the cable joint supplying power to the 27.5kV in the traction manner as claimed in claim 1, wherein the number W of the continuous sampling points is 5.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5323117A (en) * | 1989-10-25 | 1994-06-21 | Hitachi Cable, Ltd. | Method for detecting partial discharge in an insulation of an electric power apparatus |
| CN104407270A (en) * | 2014-12-04 | 2015-03-11 | 国家电网公司 | Online fault monitoring device for cable connector in 10-35kV power distribution network and method for evaluating system state |
| CN105372569A (en) * | 2015-12-05 | 2016-03-02 | 国网浙江省电力公司丽水供电公司 | Cable joint insulation state online monitoring apparatus and monitoring method |
| CN108761277A (en) * | 2018-07-26 | 2018-11-06 | 国网福建省电力有限公司莆田供电公司 | A kind of cable and junction malfunction indicator and on-line monitoring system |
| WO2019173949A1 (en) * | 2018-03-12 | 2019-09-19 | Abb Schweiz Ag | Apparatus and method for monitoring temperature of cable joint of cable connected to gas insulated switchgear |
-
2021
- 2021-11-01 CN CN202111282836.1A patent/CN114002553A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5323117A (en) * | 1989-10-25 | 1994-06-21 | Hitachi Cable, Ltd. | Method for detecting partial discharge in an insulation of an electric power apparatus |
| CN104407270A (en) * | 2014-12-04 | 2015-03-11 | 国家电网公司 | Online fault monitoring device for cable connector in 10-35kV power distribution network and method for evaluating system state |
| CN105372569A (en) * | 2015-12-05 | 2016-03-02 | 国网浙江省电力公司丽水供电公司 | Cable joint insulation state online monitoring apparatus and monitoring method |
| WO2019173949A1 (en) * | 2018-03-12 | 2019-09-19 | Abb Schweiz Ag | Apparatus and method for monitoring temperature of cable joint of cable connected to gas insulated switchgear |
| CN108761277A (en) * | 2018-07-26 | 2018-11-06 | 国网福建省电力有限公司莆田供电公司 | A kind of cable and junction malfunction indicator and on-line monitoring system |
Non-Patent Citations (2)
| Title |
|---|
| 申日青, 中国铁道出版社 * |
| 邱平: "《建筑工程结构检测数据的处理》", 30 April 2002, 中国环境科学出版社 * |
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Application publication date: 20220201 |