CN110208637B - Isolated online monitoring device and method for direct-current bushing tap grounding - Google Patents
Isolated online monitoring device and method for direct-current bushing tap grounding Download PDFInfo
- Publication number
- CN110208637B CN110208637B CN201910534512.9A CN201910534512A CN110208637B CN 110208637 B CN110208637 B CN 110208637B CN 201910534512 A CN201910534512 A CN 201910534512A CN 110208637 B CN110208637 B CN 110208637B
- Authority
- CN
- China
- Prior art keywords
- current
- grounding
- coil
- direct current
- direct
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
Abstract
The invention relates to an isolated online monitoring device and method for direct current bushing tap grounding, wherein the device comprises a current injection coil, a current detection coil, a grounding cap, a control unit and a detection unit; the injection coil is positioned in the direct current sleeve base and sleeved on the ground screen lead; the current detection coil is positioned in the grounding cap and sleeved on the end screen leading-out guide rod, the control unit and the detection unit are both installed in the direct current sleeve base, the control unit is connected with the injection coil, and the detection unit is connected with the current detection coil. The method comprises the following steps: the control unit applies high-frequency pulse current with pulse frequency periodically changing along with time to the injection coil, and the current detection unit collects integral of voltage signals of the current detection coil through the current detection coil; the detection unit judges the end screen grounding performance of the direct current sleeve through the distortion rate. The invention realizes the on-line real-time monitoring function of the direct current sleeve tap grounding, can find the fault of the direct current sleeve tap grounding in time, and has the characteristics of isolated monitoring and no influence on the tap grounding reliability.
Description
Technical Field
The invention belongs to the technical field of high-voltage electrical equipment, and particularly relates to an isolated online monitoring device and method for direct-current bushing tap grounding.
Background
For a high-voltage bushing with a tail screen, reliable grounding of the tail screen must be ensured in the operation process, when the grounding of the tail screen is poor, uniform electric field distribution cannot be maintained between a high-voltage part of the bushing and the ground, the tail screen generates higher suspension potential and discharges with the ground part, and the normal operation of the high-voltage bushing is influenced.
The direct current bushing tap grounding current is constant small current, and magnetic field interference sources are more in the working environment, so that the direct current bushing tap grounding current is difficult to accurately detect by a common isolation type means; the contact type measuring method of the grounding current of the end screen can influence the reliable connection of the end screen and the ground, has risks such as discharging and the like, generates adverse effects and reduces the reliability of grounding of the end screen. At present, the grounding state of the end screen during the running of the direct current sleeve is mainly judged by infrared temperature measurement, and intermittent discharge which does not cause obvious temperature rise is difficult to find in time.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an isolated online monitoring device and method for direct-current bushing tap grounding.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
an isolated online monitoring device for direct current bushing tap grounding comprises a current injection coil, a current detection coil, a grounding cap, a control unit and a detection unit; the grounding cap is arranged on the outer side of the direct current sleeve base and connects the end screen with the ground at the tail end, and the injection coil is positioned in the direct current sleeve base and sleeved on the ground screen lead; the current detection coil is positioned in the grounding cap and sleeved on the end screen leading-out guide rod, a metal shell of the grounding cap forms a magnetic shield for the current detection coil, the control unit and the detection unit are both installed in the direct current sleeve base, the control unit is connected with the injection coil, and the detection unit is connected with the current detection coil.
Further, the current detection coil adopts a self-integration Rogowski coil.
A monitoring method of an isolated online monitoring device such as direct current bushing tap grounding comprises the following steps:
step 1, in the running process of a direct current sleeve, a control unit applies high-frequency PWM pulse current with pulse frequency f periodically changing along with time to an injection coil, and a current detection unit collects integral K of a voltage signal of a current detection coil through the current detection coil;
and 2, analyzing the relation K (g) and (f) between the pulse current frequency f and the integral K of the current detection coil voltage signal by the detection unit, setting a linear distortion threshold of a linear distortion function h, and judging the end screen grounding performance of the direct current sleeve according to the distortion rate.
Further, the method for judging the end screen grounding performance of the direct current bushing through the distortion rate in the step 2 is as follows:
the direct current bushing end screen is well grounded when the linear distortion rate is lower than a linear distortion threshold value;
secondly, when the function K is g (f), obvious peaks or troughs appear, or the linear distortion rate exceeds a set linear distortion threshold value, the direct-current bushing end screen is poorly grounded.
The invention has the advantages and positive effects that:
the invention realizes the on-line real-time monitoring function of the direct current bushing end screen grounding by utilizing different response characteristics of the grounding loop to the injected current under different grounding states, can find out the poor grounding fault of the direct current bushing end screen in time, has no direct contact between the monitoring loop and the end screen grounding loop, does not influence the end screen grounding reliability, and has the characteristics of isolated monitoring and no influence on the end screen grounding reliability.
Drawings
FIG. 1 is a schematic diagram of an on-line monitoring device of the present invention; (ii) a
FIG. 2 is a graph of injection current frequency versus current detection coil integrated signal;
in the figure, 1-sleeve external insulation, 2-capacitance screen, 3-ground screen lead wire, 4-injection coil, 5-grounding cap, 6-current detection coil, 7-end screen lead-out guide rod, 8-sleeve base, 9-potential tap, 10-current-carrying conductor, 11-control unit and 12-detection unit.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
An isolated online monitoring device for direct current bushing end screen grounding, as shown in fig. 1, comprises a direct current bushing base (8), a current injection coil C1(4) Current detecting coil C2(6) The device comprises a grounding cap (5), a control unit (11) and a detection unit (12). The grounding cap is arranged on the outer side of the direct current sleeve base, the direct current sleeve base is arranged together with the capacitive screen (2), the capacitive screen is provided with a potential tap (9), the center of the capacitive screen is provided with a current-carrying conductor (10), and the capacitive screen is externally provided with a sleeve outer insulator (1). The injection coil C1Is positioned in the direct current sleeve base (8) and is sleeved on the ground screen lead (3). The current detecting coil C2Is positioned in the grounding cap and is sleeved on the end screen lead-out guide rod (7), and the current detection coil C2A self-integrating rogowski coil is used. The grounding cap connects the end screen with the ground at the tail end, and the metal shell of the grounding cap is opposite to the current detecting coil C2Forming a magnetically shielded, injection coil C1And a current detecting coil C2There is no direct electromagnetic coupling. The control unit (11) and the detection unit (12) are both arranged in the direct current sleeve base, and the control unit and the injection coil C1Connected with the detection unit and the current detection coil C2Are connected.
After the isolated online monitoring device operates, the control unit sends out high-frequency PWM pulse current i1Applied to the injection coil C1The ground screen leads are at the original direct current iDGenerating an additional alternating current induction current ieThe current flows back to the ground through the grounding cap after being led out of the guide rod through the end screen. Current detecting coil C2Inducing a voltage signal u2And passed to the detection unit. Injection current i1The pulse frequency f of the current detection coil changes periodically with time, and when the grounding of the end screen is good, the voltage signal u of the current detection coil2The integral K of (d) is linearly related to the frequency f. The detection unit analyzes the pulse current frequency f and the current detection coil integral signalThe relationship K between K is g (f) and, as shown in fig. 2, a linear distortion threshold of the function h is set. When the distortion rate of the function h is low, the direct current sleeve end screen is well grounded (a straight line in fig. 2), and when the function K is g (f), a distinct peak (valley) appears and the distortion rate exceeds a set threshold value, the direct current sleeve end screen is poorly grounded (a curved line B in fig. 2).
Based on the isolated online monitoring device for direct-current bushing tap grounding, the isolated online monitoring method comprises the following steps:
step 1, in the process of direct current sleeving, the control unit injects a coil C into the sleeve1Applying a high-frequency PWM pulse current with a pulse frequency f periodically changing with time, and passing a current detection unit through a current detection coil C2Collecting current detection coil voltage signal u2The integral K of (2);
step 2, the detection unit analyzes the pulse current frequency f and the current detection coil voltage signal u2And setting a linear distortion threshold of the linear distortion function h, and judging the relationship K of the integral K as g (f) in the following way:
1. when the distortion rate of the linear distortion function h is lower than the linear distortion threshold value, the direct current bushing end screen is well grounded
2. When the function K (g), (f) has obvious peaks (valleys) or the distortion rate exceeds a set linear distortion threshold, the direct current bushing end screen is poorly grounded.
Nothing in this specification is said to apply to the prior art.
It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.
Claims (2)
1. A monitoring method of an isolated online monitoring device for direct current bushing tap grounding is characterized in that: the isolated online monitoring device for direct-current bushing end screen grounding comprises a current injection coil, a current detection coil, a grounding cap, a control unit and a detection unit; the grounding cap is arranged on the outer side of the direct current sleeve base and connects the end screen with the ground at the tail end, and the injection coil is positioned in the direct current sleeve base and sleeved on the ground screen lead; the current detection coil is positioned in the grounding cap and sleeved on the end screen leading-out guide rod, a metal shell of the grounding cap forms a magnetic shield for the current detection coil, the control unit and the detection unit are both arranged in the direct current sleeve base, the control unit is connected with the injection coil, and the detection unit is connected with the current detection coil; the monitoring method comprises the following steps:
step 1, in the running process of a direct current sleeve, a control unit applies high-frequency PWM pulse current with pulse frequency f periodically changing along with time to an injection coil, and a current detection unit collects integral K of a voltage signal of a current detection coil through the current detection coil;
and 2, analyzing the relation K (g) and (f) between the pulse current frequency f and the integral K of the current detection coil voltage signal by the detection unit, setting a linear distortion threshold of a linear distortion function h, and judging the end screen grounding performance of the direct current sleeve according to the distortion rate.
2. The monitoring method of the isolated online monitoring device for direct current bushing tap grounding according to claim 1, characterized in that: the method for judging the end screen grounding performance of the direct current casing through the distortion rate in the step 2 comprises the following steps:
the direct current bushing end screen is well grounded when the linear distortion rate is lower than a linear distortion threshold value;
secondly, when the function K is g (f), obvious peaks or troughs appear, or the linear distortion rate exceeds a set linear distortion threshold value, the direct-current bushing end screen is poorly grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910534512.9A CN110208637B (en) | 2019-06-20 | 2019-06-20 | Isolated online monitoring device and method for direct-current bushing tap grounding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910534512.9A CN110208637B (en) | 2019-06-20 | 2019-06-20 | Isolated online monitoring device and method for direct-current bushing tap grounding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110208637A CN110208637A (en) | 2019-09-06 |
| CN110208637B true CN110208637B (en) | 2021-04-20 |
Family
ID=67793431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910534512.9A Active CN110208637B (en) | 2019-06-20 | 2019-06-20 | Isolated online monitoring device and method for direct-current bushing tap grounding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110208637B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111599584B (en) * | 2020-07-20 | 2020-10-23 | 广东电网有限责任公司东莞供电局 | High-voltage bushing end screen device |
| CN112630696B (en) * | 2020-12-07 | 2022-09-09 | 广西电网有限责任公司电力科学研究院 | Capacitive screen coupling simulation testing device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4914382A (en) * | 1987-10-14 | 1990-04-03 | Hydro-Quebec | High voltage measuring circuit coupled to the capacitive grounding tap bushing of an HV device |
| CN201600390U (en) * | 2009-12-10 | 2010-10-06 | 南京电气（集团）有限责任公司 | Tap measuring terminal of high voltage electrical apparatus |
| CN203705077U (en) * | 2014-02-20 | 2014-07-09 | 国家电网公司 | Temperature and grounding capacitance current online monitoring device of transformer bushing end screen |
| CN105606916A (en) * | 2015-09-14 | 2016-05-25 | 陈爱文 | Method of generating grounding device test current |
| CN106940415A (en) * | 2017-02-07 | 2017-07-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | The detecting system of capacitance sleeve pipe with measurement terminal and end shield ground terminal |
| CN107677916A (en) * | 2017-09-04 | 2018-02-09 | 中国电力科学研究院 | End shield of high-voltage bushing ground shield and end shield of high-voltage bushing |
-
2019
- 2019-06-20 CN CN201910534512.9A patent/CN110208637B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4914382A (en) * | 1987-10-14 | 1990-04-03 | Hydro-Quebec | High voltage measuring circuit coupled to the capacitive grounding tap bushing of an HV device |
| CN201600390U (en) * | 2009-12-10 | 2010-10-06 | 南京电气（集团）有限责任公司 | Tap measuring terminal of high voltage electrical apparatus |
| CN203705077U (en) * | 2014-02-20 | 2014-07-09 | 国家电网公司 | Temperature and grounding capacitance current online monitoring device of transformer bushing end screen |
| CN105606916A (en) * | 2015-09-14 | 2016-05-25 | 陈爱文 | Method of generating grounding device test current |
| CN106940415A (en) * | 2017-02-07 | 2017-07-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | The detecting system of capacitance sleeve pipe with measurement terminal and end shield ground terminal |
| CN107677916A (en) * | 2017-09-04 | 2018-02-09 | 中国电力科学研究院 | End shield of high-voltage bushing ground shield and end shield of high-voltage bushing |
Non-Patent Citations (2)
| Title |
|---|
| 带电检测电容型电流互感器/套管末屏接地断开故障可行性研究;童歆 等;《湖北电力》;20171231;第41卷(第12期);第18-21、27页 * |
| 油浸式电流互感器绝缘缺陷带电检测研究;张明举;《中国优秀硕士学位论文全文数据库•工程科技Ⅱ辑》;20170615(第6期);正文第10-14页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110208637A (en) | 2019-09-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110208637B (en) | Isolated online monitoring device and method for direct-current bushing tap grounding | |
| Stone | Partial discharge diagnostics and electrical equipment insulation condition assessment | |
| EP1310803A3 (en) | Method for detecting partial discharge | |
| CN204044296U (en) | A kind of partial discharge detecting system | |
| CN105953911A (en) | Vibration sensor used for monitoring mechanical fault of high-voltage circuit breaker | |
| CN1851489A (en) | Variable frequency high-voltage motor insulated local discharge measuring method and its special measuring instrument | |
| CN106526383B (en) | Lightning arrester state monitoring system and monitoring method | |
| EP3312617B1 (en) | Method and device for testing a galvanic connection of a high-voltage condenser bushing assembly | |
| Qi et al. | Severity diagnosis and assessment of the partial discharge provoked by high-voltage electrode protrusion on GIS insulator surface | |
| CN105675933A (en) | Ignition circuit of controllable discharge sphere gap in reactor inter-turn insulation detector | |
| US10161987B2 (en) | Insulation degradation monitoring device | |
| JP2009168489A (en) | Insulation monitoring apparatus and insulation diagnosis method | |
| JP2002536643A (en) | Apparatus and method for testing electrical conductor coatings | |
| JP2011252778A (en) | Method for detecting partial discharge of electrical device using magnetic field probe | |
| CN113189515A (en) | IFRA magnetic coupling-based reactor turn-to-turn short circuit fault non-contact type online detection method | |
| EP2209014A1 (en) | Partial corona discharge detection | |
| CN111880059A (en) | Partial discharge test platform and method for high-voltage switch cabinet insulating part | |
| CN111398730A (en) | Power distribution network based on passive injection direct current signal and fault identification method thereof | |
| CN216560779U (en) | Frequency domain dielectric response live-line test system of high-voltage bushing | |
| Wanninger | Apparent charge measurement in GIS by modern diagnostic methods | |
| Kakimoto et al. | Long-term online partial discharge trend monitoring for cast resin transformers in switchboard | |
| CN104614645A (en) | GIS and optimization method of integrated earthed ultrahigh-frequency partial discharge sensor of GIS | |
| Blufpand et al. | Partial discharge recognition of insulation defects in HVDC GIS and a calibration approach | |
| WO2008096298A2 (en) | A method for detecting signals produced by partial electric discharges | |
| Zhang et al. | Study on the self-sensing partial discharge detection method for power transformers adopting its component as ultra-high frequency sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |