CN106300211A - A kind of line terminal lightning protection method - Google Patents
A kind of line terminal lightning protection method Download PDFInfo
- Publication number
- CN106300211A CN106300211A CN201610655747.XA CN201610655747A CN106300211A CN 106300211 A CN106300211 A CN 106300211A CN 201610655747 A CN201610655747 A CN 201610655747A CN 106300211 A CN106300211 A CN 106300211A
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- gapless
- line
- transformer station
- transformer
- type metal
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G13/00—Installations of lightning conductors; Fastening thereof to supporting structure
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Abstract
The invention discloses a kind of line terminal lightning protection method, when transformer station place allows, gapless transformer substation-type metal oxide arrester is installed in transformer station's enclosure wall；When transformer station place does not allows, at transformer station's outlet the first base shaft tower, install one group of gapless Line type's MOA.Described gapless transformer substation-type metal oxide arrester or the impulse sparkover voltage of gapless Line type's MOA and residual voltage value are respectively less than the half of transformer station's inner breaker fracture impulse withstand voltage value.The inventive method is avoided that before reclosing, circuit prevents breaker fracture breakdown when being again struck by lightning or chopper explodes after circuit breaker trip, improves safety and reliability, improves protective margin, cost-effective.
Description
Technical field
The invention belongs to power system lightning-protecting engineering field, be specifically related to a kind of line terminal lightning protection method.
Background technology
One of danger of transformer station is the lightning surge intrusion produced from thunderbolt circuit near-end.When substation line chopper
When being in after stand-by heat, tripping operation the three state such as misaligned before reclosing, after tripping operation, breaker fracture, current transformer etc. are the most de-
From the protection of bus spark gap, the lightning wave that now thunderbolt outlet near-end produces can be sent out when being transferred to breaker fracture along circuit
Raw total reflection, when ignoring lightning wave in the decay that short lead transmits, echo superposition incidence wave makes the lightning surge of fracture
Double, thus produce the lightning surge of very amplitude, in making chopper, current transformer etc., insulation breakdown is damaged, and power frequency
Afterflow can not be excised in time, will cause equipment explosion.
For during preventing lightning stroke trip again thunderbolt break the breaker fracture of tripping, general require the most defeated at thunder and lightning
Electric line terminal installs metal oxide arrester additional.After 220kV circuit after putting into operation part is sampled checking, have found that
Place is limited the circuit that cannot install transformer substation-type spark gap in transformer station's enclosure wall additional, has the most all installed circuit on terminal tower additional
Spark gap.Such spark gap, because being difficult to annual regular inspection, causes short circuit for avoiding damage to crops caused by thunder to puncture, and it is frequently with band series connection insulation
The metal oxide arrester in sub-gap.Even if it addition, in part 220kV line segregation transformer station, place is enough, but owing to setting
Meter custom or designer replicate the reasons such as Other Engineering drawing, also use line terminal tower and install arrester with gaps additional
Mode.And this kind of spark gap exists with transformer station inner breaker, current transformer etc., and apparatus insulated level is unmatched lacks
Fall into, therefore breaker fracture cannot be formed and be effectively protected.
The version of discharging gap directly determines the impulsive discharge protective value of spark gap, the therefore line type of band gap
The protection feature of metal oxide arrester depends on the impulse sparkover voltage value of external serial gap.According to People's Republic of China's electricity
Power industry standard (DL/T 815-2012) " transmission line of alternation current polymeric metal oxide surge arrester ", 220kV line type
The impulse sparkover voltage of spark gap is 900kV, and the rated lightning impulse of 220kV line-breaker is pressure for 1050kV, seems
The impulse sparkover voltage of Transmission Line Arrestor can form protective effect to 220kV line-breaker, and actually this is not so.
Below with three example explanations:
: 2016 year certain certain a 220kV transformer station one 220kV outlet C phase conductor of province's first area of example is away from transformer station 7.5km
Place suffers continuous 4 lightning discharges of same thunderbolt, ultimately results in substation breakers fracture and is repeatedly punctured.The fracture punctured
Forming closed-loop path with the dissociated air of insulator periphery and provide path for short circuit current, in causing transformer station, relay protection is repeatedly
Action, tripping threephase switch, and blocked line reclosing, cause Pyatyi electric power safety event.Postmortem line terminal tower
Install spark gap (line type has interval) is intact, function normal and attonity record during fault.
The 220kV outlet of another 220kV transformer station of 2: 2005 years these provinces's first area (being areal with upper example) of example
Chopper also there occurs lightning surge intrusion, makes breaker fracture puncture, and ultimately results in chopper blast, and in station, 220kV is female simultaneously
Line has a power failure and causes many times 220kV line outage, expands power failure range.This circuit is also utilized in line terminal tower and installs interband
The mode of gap line type spark gap, postmortem spark gap function is intact, but not operating.
One 220kV transformer station 220kV wire-outgoing breaker generation lightning wave in 3: 2014 years these another areas of province of example enters
Invading, breaker fracture is breakdown, but fracture is from arc extinguishing.Although this time lightning surge intrusion explodes without result in chopper, but to disconnected
Road device finds its serious ablation of arc-chutes contact after disintegrating.
According to investigations, three above case all uses the side installing metal oxide surge attester with series gap at circuit terminal tower additional
Formula, the discharge voltage value of spark gap is 900kV, residual voltage value is 600kV, and the impulse withstand voltage of transformer station's inner breaker is
1050kV.After being struck by lightning due to high-tension line, lightning wave is transferred to breaker fracture and can be totally reflected, and now fracture bears
Voltage by double, i.e. 2 times lightning voltages.Even if at this moment leakage conductor is failure to actuate, breaker fracture has born peak value
Being the overvoltage of 2 times of spark gap impulse sparkover voltages (about 1800kV), if considering to superpose with power-frequency voltage peak value, fracture even may be used
The overvoltage that peak value is 1980kV can be born.When leakage conductor action, the voltage peak that breaker fracture bears is 2 times and keeps away
Thunder device residual voltage (about 1200kV), if considering to superpose with power-frequency voltage peak value, then fracture may bear peak value is the most electric of 1380kV
Pressure.
It is to say, no matter line type terminal lightning arrestor movement is whether, breaker fracture all may bear 1380kV extremely
The impulse overvoltage of 1980kV, this magnitude of voltage is much larger than impulse withstand voltage value 1050kV of fracture, it is sufficient to punctures breaker fracture, says
Bright Transmission Line Arrestor can not meet far away the Insulation Coordination requirement of breaker fracture.And closer to but less than spark gap impact put
The thunderbolt of piezoelectric voltage can produce the biggest overvoltage.
Summary of the invention
The technical problem to be solved in the present invention is to provide one and is avoided that after circuit breaker trip before reclosing, circuit is again
Prevent breaker fracture breakdown when being struck by lightning or chopper explodes, improve safety and reliability, improve protective margin, joint
The about line terminal lightning protection method of cost and device thereof.
The present invention solves above-mentioned technical problem by the following technical solutions:
A kind of line terminal lightning protection method, when transformer station place allows, installs gapless power transformation in transformer station's enclosure wall
Site type metal oxide arrester；When transformer station place does not allows, install at transformer station's outlet the first base shaft tower one group without
Gap Line type's MOA.
The installation method of described gapless transformer substation-type metal oxide arrester is: in transformer station's enclosure wall, and chopper is even
Connecing current transformer, current transformer connection line disconnecting switch, line disconnecting switch connects portal frame, gapless transformer substation-type
Metal oxide arrester is installed in parallel on line disconnecting switch side.
Hitch connecting cantilever frame is passed through in described gapless Line type's MOA one end, and the other end passes through
Disconnector connects transmission line of electricity；Connecting insulator string between cantilever shalving and transmission line of electricity.
Described first base shaft tower is less than 50 meters with the distance of transformer station.
Described first base shaft tower is located at outside transformer station's enclosure wall.
Described gapless transformer substation-type metal oxide arrester or gapless Line type's MOA are with disconnected
The electrical distance of road device fracture is less than or equal to (Uj-Ub5)/(2 α/v), and wherein, Uj is that the rated lightning impulse of chopper is pressure
Value, Ub5 is residual under gapless transformer substation-type metal oxide arrester or gapless Line type's MOA 5KA
Pressure value, v is velocity of wave, and α is the slope of invasion lightning wave.
Rushing of described gapless transformer substation-type metal oxide arrester or gapless Line type's MOA
Hit discharge voltage and residual voltage value is respectively less than the half of transformer station's inner breaker fracture impulse withstand voltage value.
It is an advantage of the current invention that:
1, the inventive method fundamentally can form protective effect to the primary equipment such as chopper, current transformer.Metal
The main basis that Oxide Arrester is selected is Insulation Coordination, by the level of protection of dielectric level and the spark gap of protection equipment it
Ratio, to from the point of view of line type gapless arrestyer about 1.7, and has from the point of view of the spark gap of gap about 1.15～1.2, it is clear that front to line type
The protective margin of person is relatively big, and the most important by protection equipment, and protective margin should be the biggest.
2, the inventive method is avoided that after circuit breaker trip before reclosing, when circuit is struck by lightning again, it is to avoid open circuit
Device fracture punctures or chopper blast, the second investment that saving is repaired or replacing equipment brings.
3, the inventive method can more truly, more thoroughly implement power industry anti-accident measures, has promotion prospect.Should
Just line terminal spark gap newly-built, reorganization and expansion can be corrected from the design phase by this method, it is to avoid cause bigger
Electric power safety event.Build circuit the first Ji Ta at the outer near-end of transformer station's enclosure wall, and at the first base shaft tower, install one group continuously
Gap line type metal oxide arrester, both can save transformer station's usable floor area；Maintenance work amount can be reduced again.
Accompanying drawing explanation
Fig. 1 is the structure that the inventive method installs gapless transformer substation-type metal oxide arrester in transformer station's enclosure wall
Schematic diagram.In figure: 1, chopper；2, current transformer；3, line disconnecting switch；4, portal frame；5, gapless transformer substation-type gold
Belong to Oxide Arrester；6, line voltage distribution transformer；7, enclosure wall.
Fig. 2 is the structural representation that the inventive method installs gapless Transmission Line Arrestor, in figure, 1, cantilever shalving；2, exhausted
Edge substring；3, transmission line of electricity；4, disconnector；5, gapless Line type's MOA；6, earthing jumper；7, hang
Mechanism, 8, hang device for hoisting.
Detailed description of the invention
Below in conjunction with accompanying drawing, the detailed description of the invention of the present invention is elaborated, but do not constitute the claims in the present invention
The restriction of protection domain.
A kind of line terminal lightning protection method, it is contemplated that the requirement to electrical distance, when transformer station place allows, in power transformation
Enclosure wall of standing is interior installs gapless transformer substation-type metal oxide arrester；When transformer station place does not allows, in transformer station's outlet
One group of gapless Line type's MOA is installed at first base shaft tower.
As it is shown in figure 1, the installation method of described gapless transformer substation-type metal oxide arrester 5 is: enclose in transformer station
In wall 7, transformer output power line connects chopper 1, and chopper 1 connects current transformer 2, current transformer 2 connection line
Disconnecting switch 3, the outlet line of line disconnecting switch 3 is connected to outlet after portal frame 4.Gapless transformer substation-type metal-oxide
Spark gap 5 is arranged on line disconnecting switch 4 side, gapless transformer substation-type metal oxide arrester 5 one end connection wiring line
The outlet line of road disconnecting switch 3, other end connection wiring line road voltage transformer 6.
As in figure 2 it is shown, described gapless Line type's MOA 5 one end is by hitch 7 connecting cantilever
Frame 1, the other end connects transmission line of electricity 3 by disconnector 4；Insulator chain 2 one end by hang device for hoisting 8 connecting cantilever frame 1, another
End connects transmission line of electricity 3.Gapless Line type's MOA 5 is by earthing jumper 6 ground connection.
Described gapless transformer substation-type metal oxide arrester or gapless Line type's MOA are with disconnected
Road device fracture must meet following electrical distance could effective protective breaker fracture:
When transmission line of electricity is struck by lightning, general transformer station Lightning disturbance ripple is the oblique angle ripple of exponential function, is set to u=α
T, u be the invasion voltage of lightning wave, α be the invasion slope of lightning wave, t be the time, if described spark gap and breaker fracture
Electrical distance is L, then maximum voltage value Ud that breaker fracture bears is:
Ud=Ub5+2 α * L/v (1)
Wherein, the residual voltage value under Ub5 is described spark gap 5kA；V is velocity of wave.
Formula (1) shows, when the electrical distance L of described spark gap Yu breaker fracture is not equal to zero, breaker fracture holds
Maximum impact magnitude of voltage Δ higher than the Ub5 U being subject to, Δ U=2 α * L/v, and distance is the most remote, Δ U is the biggest.
If the rated lightning impulse of chopper is pressure, Uj represents, for making spark gap fracture can form effectively protection, then
Require:
Ud≤Uj
That is: Ub5+2 α * L/v≤Uj
: L≤(Uj-Ub5)/(2 α/v)
It is to say, when the electrical distance of described spark gap with breaker fracture is less than or equal to (Uj-Ub5)/(2 α/v)
Time, can effective protective breaker fracture.
One group of gapless Line type's MOA is installed at transformer station's outlet the first base shaft tower, but this base
The distance of shaft tower and transformer station is no more than 50 meters, and preferred plan is: build the first base shaft tower near transformer station's enclosure wall is outer, and
At the first base shaft tower, install one group of gapless Line type's MOA, both can save transformer station's usable floor area；Again
Maintenance work amount can be reduced.
Rushing of described gapless transformer substation-type metal oxide arrester or gapless Line type's MOA
Hit discharge voltage and residual voltage value is respectively less than the half of transformer station's inner breaker fracture impulse withstand voltage value.
Certain 220kV transformer station use the inventive method install away from outlet the first base shaft tower of 40 meters from transformer station one group without
Gap Line type's MOA, repeatedly suffers, the first half of the year in 2016, the equal correct operation that is struck by lightning, and effectively protection is resolved
Road device fracture.
Claims (7)
1. a line terminal lightning protection method, it is characterised in that: when transformer station place allows, nothing is installed in transformer station's enclosure wall
Gap transformer substation-type metal oxide arrester；When transformer station place does not allows, fill at transformer station's outlet the first base shaft tower
If one group of gapless Line type's MOA.
2. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described gapless transformer substation-type metal
The installation method of Oxide Arrester is: in transformer station's enclosure wall, and chopper connects current transformer, current transformer connection line
Disconnecting switch, line disconnecting switch connects portal frame, and gapless transformer substation-type metal oxide arrester is installed in parallel at circuit
Disconnecting switch side.
3. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described gapless line type metal oxygen
Hitch connecting cantilever frame is passed through in compound spark gap one end, and the other end connects transmission line of electricity by disconnector；Cantilever shalving and defeated
Connecting insulator string between electric line.
4. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described first base shaft tower and transformer station
Distance less than 50 meters.
5. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described first base shaft tower is located at power transformation
Stand outside enclosure wall.
6. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described gapless transformer substation-type metal
Oxide Arrester or gapless Line type's MOA are less than or equal to the electrical distance of breaker fracture
(Uj-Ub5)/(2 α/v), wherein, Uj is the rated lightning impulse pressure voltage of chopper, and Ub5 is gapless transformer substation-type metal oxygen
Residual voltage value under compound spark gap or gapless Line type's MOA 5KA, v is velocity of wave, and α is invasion lightning wave
Slope.
7. a kind of line terminal as claimed in claim 1 lightning protection method, it is characterised in that: described gapless transformer substation-type metal
Oxide Arrester or the impulse sparkover voltage of gapless Line type's MOA and residual voltage value are respectively less than transformer station
The half of inner breaker fracture impulse withstand voltage value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610655747.XA CN106300211A (en) | 2016-08-11 | 2016-08-11 | A kind of line terminal lightning protection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610655747.XA CN106300211A (en) | 2016-08-11 | 2016-08-11 | A kind of line terminal lightning protection method |
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| CN106300211A true CN106300211A (en) | 2017-01-04 |
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ID=57668604
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| CN201610655747.XA Pending CN106300211A (en) | 2016-08-11 | 2016-08-11 | A kind of line terminal lightning protection method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107727974A (en) * | 2017-11-09 | 2018-02-23 | 广西电网有限责任公司钦州供电局 | Test of lightning arrester device and method based on C-V characteristic skew |
| CN111668799A (en) * | 2020-06-15 | 2020-09-15 | 杭州如剑电子设备有限公司 | Double-end ground connection arrester base |
| CN112018746A (en) * | 2020-09-01 | 2020-12-01 | 中铁一局集团电务工程有限公司 | Method for reducing lightning strike tripping of overhead power line |
| CN113178853A (en) * | 2021-04-29 | 2021-07-27 | 广东电网有限责任公司电力科学研究院 | Overvoltage protection system for lightning invasion waves on transformer substation line side |
| CN114243619A (en) * | 2021-11-11 | 2022-03-25 | 国网浙江省电力有限公司温州市洞头区供电公司 | Lightning flashover protection device for island |
| CN118671657A (en) * | 2024-08-13 | 2024-09-20 | 江苏高电电力设备有限公司 | Transformer power frequency withstand voltage testing device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1092242A (en) * | 1996-09-11 | 1998-04-10 | Toubu Tetsudo Kk | Arrester device |
| JP2004158225A (en) * | 2002-11-05 | 2004-06-03 | Ngk Insulators Ltd | Lightning insulator device |
| KR20050080713A (en) * | 2004-02-10 | 2005-08-17 | 조성우 | How to prevent reverse flashover of transmission pylon |
| CN202978006U (en) * | 2012-10-10 | 2013-06-05 | 浙江省电力设计院 | Ultrahigh voltage intelligent substation medium-voltage side HGIS power distribution device |
| CN203871674U (en) * | 2013-12-17 | 2014-10-08 | 河南省电力勘测设计院 | 220kV power distribution unit outgoing line structure |
| CN205304172U (en) * | 2015-11-12 | 2016-06-08 | 江西瑞林电气自动化有限公司 | Room outer door type high voltage power distribution device |
-
2016
- 2016-08-11 CN CN201610655747.XA patent/CN106300211A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1092242A (en) * | 1996-09-11 | 1998-04-10 | Toubu Tetsudo Kk | Arrester device |
| JP2004158225A (en) * | 2002-11-05 | 2004-06-03 | Ngk Insulators Ltd | Lightning insulator device |
| KR20050080713A (en) * | 2004-02-10 | 2005-08-17 | 조성우 | How to prevent reverse flashover of transmission pylon |
| CN202978006U (en) * | 2012-10-10 | 2013-06-05 | 浙江省电力设计院 | Ultrahigh voltage intelligent substation medium-voltage side HGIS power distribution device |
| CN203871674U (en) * | 2013-12-17 | 2014-10-08 | 河南省电力勘测设计院 | 220kV power distribution unit outgoing line structure |
| CN205304172U (en) * | 2015-11-12 | 2016-06-08 | 江西瑞林电气自动化有限公司 | Room outer door type high voltage power distribution device |
Non-Patent Citations (2)
| Title |
|---|
| 吴广宁: "《过电压防护的理论与技术》", 31 August 2015, 中国电力出版社 * |
| 张育华等: "线路避雷器的应用及监测", 《电磁避雷器》 * |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107727974A (en) * | 2017-11-09 | 2018-02-23 | 广西电网有限责任公司钦州供电局 | Test of lightning arrester device and method based on C-V characteristic skew |
| CN107727974B (en) * | 2017-11-09 | 2023-12-29 | 广西电网有限责任公司钦州供电局 | Lightning arrester test device and method based on volt-ampere characteristic deviation |
| CN111668799A (en) * | 2020-06-15 | 2020-09-15 | 杭州如剑电子设备有限公司 | Double-end ground connection arrester base |
| CN111668799B (en) * | 2020-06-15 | 2021-05-18 | 浙江精创电力科技有限公司 | Double-end ground connection arrester base |
| CN112018746A (en) * | 2020-09-01 | 2020-12-01 | 中铁一局集团电务工程有限公司 | Method for reducing lightning strike tripping of overhead power line |
| CN113178853A (en) * | 2021-04-29 | 2021-07-27 | 广东电网有限责任公司电力科学研究院 | Overvoltage protection system for lightning invasion waves on transformer substation line side |
| CN113178853B (en) * | 2021-04-29 | 2023-03-14 | 广东电网有限责任公司电力科学研究院 | Overvoltage protection system for lightning invasion waves on transformer substation line side |
| CN114243619A (en) * | 2021-11-11 | 2022-03-25 | 国网浙江省电力有限公司温州市洞头区供电公司 | Lightning flashover protection device for island |
| CN118671657A (en) * | 2024-08-13 | 2024-09-20 | 江苏高电电力设备有限公司 | Transformer power frequency withstand voltage testing device |
| CN118671657B (en) * | 2024-08-13 | 2024-12-20 | 江苏高电电力设备有限公司 | A transformer power frequency withstand voltage test device |
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