CN106872860B - Cable line partial discharge signal identification and phase judgment method - Google Patents
Cable line partial discharge signal identification and phase judgment method Download PDFInfo
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- CN106872860B CN106872860B CN201510925477.5A CN201510925477A CN106872860B CN 106872860 B CN106872860 B CN 106872860B CN 201510925477 A CN201510925477 A CN 201510925477A CN 106872860 B CN106872860 B CN 106872860B
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- 238000010168 coupling process Methods 0.000 claims description 20
- 238000005859 coupling reaction Methods 0.000 claims description 20
- 239000003990 capacitor Substances 0.000 claims description 14
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 12
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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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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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
Abstract
The invention provides a method for identifying and judging the phase of a local discharge signal of a cable circuit, which provides different methods for identifying and judging the phase respectively according to the condition that a grounding box in the cable circuit can be opened and the condition that the grounding box cannot be opened, carries out physical adjustment on a transmission path of a high-frequency signal in a cross-connected grounding cable system on the basis of not changing the structure of the original grounding system, can conveniently realize the identification and the phase judgment of the signal by utilizing the characteristics and the difference of the transmission rules of interference signals in the cable system before and after the adjustment, has the repeatability of a detection result, is easy to master and apply by field live detection personnel, and can effectively reduce the configuration cost of live detection equipment.
Description
Technical Field
The invention relates to the power transmission and transformation technology, in particular to a high-voltage cross-linked cable line partial discharge signal identification and phase judgment method in a cross-connection grounding mode.
Background
High-frequency current sensors are used for carrying out signal coupling detection on high-voltage cables on grounding leading-out wires or cross interconnection wires of accessories such as cable intermediate connectors and cable terminals, the length of cable lines reaches dozens of kilometers, the span of geographic positions is large, the interval between adjacent intermediate connectors is often more than 400m, field live detection is limited by the limitation of conditions such as cable laying and detection environments, and common detection is difficult to be carried out on all connectors, so that the distance between a detection point and an actual discharge position reaches hundreds of meters or even more; in addition, for signals generated by insulation defects of the cable body, signals at the detection joint can also cause a certain spatial distance between the detection point and an actual discharge position.
The grounding mode of three-phase cross interconnection grounding exists in a high-voltage cable line system, the signal propagation path in a single-phase cable becomes more complicated, and signals are mutually connected in series and superposed in a three-phase cable line due to the cross interconnection, so that the amplitude and the polarity of the signals detected on the three-phase cable line are similar, and the signals are easily misjudged as interference signals; in addition, the electromagnetic interference signals on site can be transmitted in the three-phase cable, so that the amplitude attenuation and waveform distortion of the discharge signals are aggravated, the difficulty in distinguishing the signals on site is further increased, the reliability of subsequent data analysis results is reduced, and great difficulty is brought to the discharge type identification and cable state evaluation work.
Disclosure of Invention
In order to overcome the defects, the invention provides a high-voltage cross-linked cable line signal identification and phase judgment method in a cross-linked grounding mode, a pulse high-frequency signal transmission loop is established, and the cable phase sequence where a suspected signal and a local discharge signal are located can be effectively and simply judged according to the change conditions of the polarity and the amplitude of the suspected signal before and after the loop is formed.
In order to achieve the purpose, the invention provides the following technical scheme:
a cable line partial discharge signal identification and phase judgment method comprises the following steps:
1) arranging a high-frequency current sensor on a cross interconnection grounding copper bar of the openable grounding box;
2) detecting a cable line by using a high-frequency current sensor;
3) when the abnormal signal is detected, fixing the detection parameters of the current sensor;
4) bridging by using a capacitor arm with the capacitance not lower than 10 nF;
5) and identifying the partial discharge signal and judging the phase of the partial discharge signal.
The method comprises the following steps:
A) arranging a high-frequency current sensor on a grounding wire of the grounding box which can not be opened;
B) detecting a cable line by using a high-frequency current sensor;
C) when the abnormal signal is detected, fixing the detection parameters of the current sensor;
D) capacitive coupling sensors with the capacitance not lower than 1nF are respectively arranged on two sides of the insulating flange of the insulating joint and are connected with each other through a short-circuit copper strip;
E) and identifying the partial discharge signal and judging the phase of the partial discharge signal.
And step 1) the cross interconnection grounding copper bars are respectively connected with the A-B phase, the B-C phase and the C-a phase of the three-phase power.
And 4) the capacitor arm is sequentially connected across the A-a phase, the B-B phase and the C-C phase of the three-phase power.
Step 5), identifying and judging the phases as follows: after the capacitor arm is bridged, abnormal signals detected by the high-frequency current sensor under fixed parameters are unchanged, and the abnormal signals are electromagnetic interference;
after the capacitor arm is bridged, the amplitude of an abnormal signal detected by the high-frequency current sensor under fixed parameters is attenuated, or the high-frequency current sensor cannot detect the abnormal signal under the fixed parameters; and recovering the abnormal signal again after the capacitor arm is removed, wherein the abnormal signal is a partial discharge signal and the partial discharge signal comes from the phase cable connected across the capacitor arm.
And D) sequentially arranging the capacitive coupling sensors at two sides of the insulation flanges of the insulation joints of the phase A, the phase B and the phase C.
Step E), identifying and judging the facies as follows: after the capacitive coupling sensors on the two sides of the insulating flange of the insulating joint are connected, abnormal signals detected by the high-frequency current sensor under fixed parameters are unchanged, and the abnormal signals are electromagnetic interference;
after the capacitive coupling sensors on the two sides of the insulating flange of the insulating joint are connected, the amplitude of an abnormal signal detected by the high-frequency current sensor under fixed parameters is attenuated, or the high-frequency current sensor cannot detect the abnormal signal under the fixed parameters; the abnormal signal is a partial discharge signal and the partial discharge signal is from a phase cable provided with a capacitive coupling sensor.
Compared with the closest prior art, the invention has the following beneficial effects:
1. the invention adopts a bridging means of a capacitance arm or a capacitance coupling sensor, carries out physical adjustment on the transmission path of the high-frequency signal in the crossed and interconnected grounding cable system on the basis of not changing the structure of the original grounding system, utilizes the characteristics and the difference of the transmission rule of the interference signal in the cable system before and after adjustment, can conveniently realize the identification and the phase judgment of the signal and has the repeatability of the detection result, and is suitable for the live detection of the high-voltage cable line.
2. The invention adopts a capacitive arm or capacitive coupling sensor bridging means to detect obvious signal change difference, has strong anti-interference capability and is easy to master and apply by field live detection personnel.
3. The cost of the capacitive arm or the capacitive coupling sensor adopted by the invention is greatly reduced compared with the cost of the existing electrified detection equipment, and the configuration cost of the electrified detection equipment can be effectively reduced.
Drawings
FIG. 1 is a schematic diagram of a capacitor arm cross-connect;
fig. 2 is a schematic diagram of a capacitively coupled sensor connection.
Wherein, 101-grounding box; 102-an overvoltage protector; 103-cross-linked copper bars; 104-a high frequency current sensor; 105-a ground line; 106-cable joint grounding lead-out wire; 107-capacitive arms; 201-a cable; 202-an insulated joint; 203-a capacitive coupling sensor; 204 short-circuit the copper strip; 205-insulating joint insulating flange.
Detailed Description
The invention will be described in further detail with reference to the following detailed description and accompanying drawings:
a high-voltage cross-linked cable line local discharge signal identification and phase judgment method in a cross-linked grounding mode is characterized in that a cross-linked structure is bridged by utilizing a capacitive coupling sensor or a capacitive arm, a high-frequency signal transmission loop of a local discharge pulse is established, and the phase sequence of a cable where a suspected local discharge signal and a local discharge source are located can be effectively and simply judged under the condition of the change of the polarity and the amplitude of the suspected local discharge signal before and after the loop is formed.
The invention provides two implementation schemes for the method for judging the partial discharge signal of the high-voltage cross-linked cable line in the cross-connection grounding mode aiming at the different management modes of the cable line grounding box.
The first scheme is as follows: under the condition that a cable circuit grounding box can be opened in the cable circuit partial discharge live detection, the scheme is as follows:
according to the illustration of FIG. 1:
(1) the high-frequency current sensor 104 is installed on the cross-interconnected copper bars 103 of the cross-interconnected grounding box 101, and the high-frequency current sensor 104 is used for detecting the partial discharge condition of the cable line in a frequency division mode.
(2) And when the three phases are found to simultaneously have abnormal signals with suspected partial discharge characteristics but with phases and amplitudes having similarity in a certain detection frequency band, the three phases are determined as suspected signals.
(3) Respectively adopting capacitance arms 107 with capacitance not less than 10nF to carry out A-a phase, B-B phase and C-C phase bridging between A, B, C three-phase upper and lower terminals of a grounding box 101, when the upper and lower terminals of a grounding system of a certain phase are bridged by adopting the capacitance arms 107, the high-frequency current sensor 104 arranged on the cross interconnected copper bar 103 cannot detect the suspected signal or the signal generates large attenuation under the original arrangement, and the signal is recovered again after removing the capacitance arms 107, so that the suspected signal is determined to come from the inside of the phase cable or the accessory thereof; if the suspected signal or the signal attribute is basically unchanged in the original setting of the high-frequency current sensor 104 disposed on the cross-interconnected copper bar after the capacitor arm 107 is connected across, it is determined that the suspected signal is derived from the environmental electromagnetic interference.
Scheme II: under the condition that a cable line grounding box cannot be opened in the partial discharge live detection of the cable line, the scheme is as follows:
according to fig. 1-2:
(1) the high-frequency current sensor 104 is mounted on the ground line 105, and the partial discharge of the cable line is detected in a divided band by the high-frequency current sensor 104.
(2) And when the three phases are found to simultaneously have abnormal signals with suspected partial discharge characteristics but with phases and amplitudes having similarity in a certain detection frequency band, the three phases are determined as suspected signals.
(3) Respectively adopting capacitive coupling sensors 203 with the installation capacitance not lower than 1nF at the near ends of two sides of an insulating flange 205 of an insulating joint of three phases of a cable line A, B, C, carrying out split-phase cross-over on the capacitive coupling sensors 203 positioned at two sides of the same joint by adopting short-circuit copper strips 204, and determining that a suspected signal comes from the inside of a phase cable or an accessory if a high-frequency current sensor 104 arranged on a grounding wire 105 of a cable line cannot detect the suspected signal or the signal is greatly attenuated under the original setting after the capacitive coupling sensors 203 positioned at two sides of the insulating flange 205 of the insulating joint of a certain phase cable 201 are crossed over; if the suspected signal can be detected by the high-frequency current sensor 104 arranged on the grounding wire 105 of the cable 201 under the original arrangement after the capacitive coupling sensors 203 on the two sides of the insulating flange 205 of the insulating joint of the cable 201 are bridged, the suspected signal is determined to be originated from the environmental electromagnetic interference.
It should be noted that the summary and the detailed description of the invention are intended to demonstrate the practical application of the technical solutions provided by the present invention, and should not be construed as limiting the scope of the present invention. Various modifications, equivalent alterations, and improvements will occur to those skilled in the art and are intended to be within the spirit and scope of the invention. Such changes and modifications are intended to be included within the scope of the appended claims.
Claims (1)
1. A cable line local discharge signal identification phase-judging method is characterized in that: the method comprises the following steps:
1) arranging a high-frequency current sensor on a cross interconnection grounding copper bar of the openable grounding box;
2) detecting a cable line by using a high-frequency current sensor;
3) when the abnormal signal is detected, fixing the detection parameters of the current sensor;
4) bridging by using a capacitor arm with the capacitance not lower than 10 nF;
5) identifying the partial discharge signal and judging the phase of the partial discharge signal;
the method comprises the following steps:
A) arranging a high-frequency current sensor on a grounding wire of the grounding box which can not be opened;
B) detecting a cable line by using a high-frequency current sensor;
C) when the abnormal signal is detected, fixing the detection parameters of the current sensor;
D) capacitive coupling sensors with the capacitance not lower than 1nF are respectively arranged on two sides of the insulating flange of the insulating joint and are connected with each other through a short-circuit copper strip;
E) identifying the partial discharge signal and judging the phase of the partial discharge signal;
step E), identifying and judging the facies as follows: after the capacitive coupling sensors on the two sides of the insulating flange of the insulating joint are connected, abnormal signals detected by the high-frequency current sensor under fixed parameters are unchanged, and the abnormal signals are electromagnetic interference;
after the capacitive coupling sensors on the two sides of the insulating flange of the insulating joint are connected, the amplitude of an abnormal signal detected by the high-frequency current sensor under fixed parameters is attenuated, or the high-frequency current sensor cannot detect the abnormal signal under the fixed parameters; the abnormal signal is a partial discharge signal, and the partial discharge signal comes from a phase cable provided with a capacitive coupling sensor;
step 5), identifying and judging the phases as follows: after the capacitor arm is bridged, abnormal signals detected by the high-frequency current sensor under fixed parameters are unchanged, and the abnormal signals are electromagnetic interference;
after the capacitor arm is bridged, the amplitude of an abnormal signal detected by the high-frequency current sensor under fixed parameters is attenuated, or the high-frequency current sensor cannot detect the abnormal signal under the fixed parameters; after the capacitor arm is removed, recovering the abnormal signal again, wherein the abnormal signal is a partial discharge signal and the partial discharge signal comes from a phase cable connected across the capacitor arm;
step 1) the cross interconnection grounding copper bar is respectively connected with an A-B phase, a B-C phase and a C-a phase of three-phase electricity;
step 4), the capacitor arm is sequentially connected across the A-a phase, the B-B phase and the C-C phase of the three-phase power in a bridging mode;
and D) sequentially arranging the capacitive coupling sensors at two sides of the insulation flanges of the insulation joints of the phase A, the phase B and the phase C.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510925477.5A CN106872860B (en) | 2015-12-14 | 2015-12-14 | Cable line partial discharge signal identification and phase judgment method |
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| CN201510925477.5A CN106872860B (en) | 2015-12-14 | 2015-12-14 | Cable line partial discharge signal identification and phase judgment method |
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| CN106872860A CN106872860A (en) | 2017-06-20 |
| CN106872860B true CN106872860B (en) | 2020-07-21 |
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| CN107907780A (en) * | 2017-11-22 | 2018-04-13 | 安徽马钢设备检修有限公司 | A kind of cable seeking discrimination method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07159479A (en) * | 1993-12-07 | 1995-06-23 | Hitachi Cable Ltd | Partial discharge measuring method |
| CN102981106A (en) * | 2012-11-12 | 2013-03-20 | 华北电力大学 | Online inspection method of three-phase cross interconnected electric cable intermediate head partial discharge |
| CN103267931A (en) * | 2013-04-19 | 2013-08-28 | 国家电网公司 | Method for positioning intersecting interconnection cable intermediate head partial discharge |
| CN103344889A (en) * | 2013-07-02 | 2013-10-09 | 华北电力大学 | Method for measuring cable partial discharge by means of capacitor wire jumper |
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2015
- 2015-12-14 CN CN201510925477.5A patent/CN106872860B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07159479A (en) * | 1993-12-07 | 1995-06-23 | Hitachi Cable Ltd | Partial discharge measuring method |
| CN102981106A (en) * | 2012-11-12 | 2013-03-20 | 华北电力大学 | Online inspection method of three-phase cross interconnected electric cable intermediate head partial discharge |
| CN103267931A (en) * | 2013-04-19 | 2013-08-28 | 国家电网公司 | Method for positioning intersecting interconnection cable intermediate head partial discharge |
| CN103344889A (en) * | 2013-07-02 | 2013-10-09 | 华北电力大学 | Method for measuring cable partial discharge by means of capacitor wire jumper |
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