1 Huang Songquan, Zhou Xueming 2, Hu Danhui 2, 2 Yao Yao, INTERNATIONAL JOURNAL 3
(1.State Grid Electric Power Company in Hubei Province, Hubei Wuhan 430077, China; 2.Hubei Electric Power Research Institute State Grid Electric Power Company, Wuhan 430077; 3.State power transmission engineering company in Hubei Province, Hubei Wuhan 430077, China)
[Abstract] Glass Insulator focus blew event has occurred many times in the country, seriously affecting the application of glass Insulator in Transmission Line.Focus blew feature for glass Insulator, depth cause analysis work, is important for effective protective measures.Leakage current through in-depth analysis of the factors that lead blew glass Insulator focus, combined with practical case studies focused on the specific reasons for Glass Insulator blew that Insulator caused severe surface contamination is the main cause of Glass Insulator focus blew.
[Keywords] Insulator glass; concentrated blew; contamination; Leakage Current
Glass Insulator blew characteristics due to a zero value, reducing manual zero measurement work, can not afford to train blew advantages, access to the vast number of transmission line operation and maintenance personnel recognized, it has been widely used in transmission lines.But in the application process, the glass Insulator also blew a spate of concentrated events, such as literature [1] Jiangsu province, a number of glass Insulator 500 kV centralized blew conducted a statistical, combined with case studies focused on the domestic glass blew fundamental Insulator The reason for the contamination caused porcelain.Tsinghua University needle specially grown for glass surface Insulator 500 kV moss phenomenon simulation test conducted to study the electrical and mechanical properties of the surface of the glass Insulator moss growth, and that its electrical properties are subject to certain contamination influence [2].Therefore, the focus for the event blew glass Insulator large-scale applications with multiple occurrences reality, analysis of the factors leading to the glass blew Insulator focus needs thorough and systematic, is important for the effective implementation of the reasons blew glass Insulator centralized analysis and take protective measures.
Coverage and homogeneity of the glass piece glass Insulator compression molded will be performed by only the tempering treatment, to form a permanent pre-stress and the inner glass surface of the tensile stress, tempering temperature, the cold air flow rate, the flow rate and air-cooled, It determines the quality of the glass steel member.Thereafter, during the entire life Insulator, tensile stress and the compressive prestress of the inner surface of the glass member is balanced, if there is mechanical or electrical stress applied stress (such as a large current, the leakage current caused serious dust contamination and the frequency of the spark etc.) damage, it will be completely broken glass sheds.
After forming the glass member to be at least twice the hot / cold thermal shock and a special heat treatment to a glass member containing impurities out of steel or bad glass member, glass Insulator after shipment to ensure a very low rate blew.But no matter several times after thermal shock or special treatment, there is still some blew rate, which is the basic characteristics of glass Insulator brought their own, blew its rate of adoption of technology and technology decisions.
As Insulator glass blew, has its own laws [3]: 1) from a time point of view, the early run, especially in the first to put into operation three years later, blew rate is relatively high, but blew the time is dispersed over the running time, will blew rate downward trend; 2) from the distribution of the product blew see, blew Insulator different strings will be dispersed on the entire line, but does not concentrate on a string or blew a large number of very small range.
Insulator weight glass forming residues after the broken glass plate umbrella blew scattered, as shown in Figure 1.
FIG 1 glass blew residues hammer Insulator
Tab.1 Self-blast residual hammer of glass insulator
(1) If the broken glass in the form of radioactive residues hammer shape, the glass blew the start position of the head member, blew in this case is caused by the quality of their glass member, such as ingredients, melting process or the like made of.
FIG 2 blew broken glass shape starting position of the head
Tab.2 Shape of broken glass which start self-blast in steel cap head
(2) If the broken glass hammer residue was scaly, then blew the start position near the bottom of the glass iron cap member, there are two possible reasons blew in this case, i.e., due to the product itself or external defects blew caused by broken glass, which force may be a mechanical stress, electrical stress may be, for continued spark blow frequency of broken glass piece and a large current caused by nonuniform leakage current, etc..
FIG 3 blew starting position near the bottom of the broken glass shaped steel cap
Tab.3 Shape of broken glass which start self-blast in steel cap bottom
(3) if the residue on the broken glass and the exit of the hammer was scaly shapes exist, the starting point is located on the shed blew glass member, blew, internal and external factors in this case are likely to lead.
Starting position of FIG. 4 blew broken glass umbrella shape on the disc
Tab.4 Shape of broken glass which start self-blast in umbrella skirt
Mainly for the mechanical stress of combat force, such as stones hit or shot (shotgun, air gun, etc.), these cases occurred in the pastoral areas (such as Qinghai, Tibet and other regions) or regions firearm does not control (such as North America).
When the line frequency to generate arc (must be present in order to initiate flashover frequency arc), the national standards and the power industry standards, Insulator acceptable frequency and duration of the current 20 kA and 0, respectively.12 s, if the time-frequency arc current is greater than 20 kA or sustained over 0.12 s, it may lead to sheet crushing glass plurality Insulator.
5 because the glass Insulator frequency due to arc blew
Tab.5 Glass insulator self-blast caused by power frequency arc
Since whether the frequency arc initiation plurality of glass sheets Insulator broken, check the “hammer residues” cap iron, steel legs and cullet or absence of the traces of the arc burning.
Insulator glass dust contamination caused by serious focus time and place multiple sheet crushing, inducing mainly based on two factors:
(1) electrical stress caused by mechanical damage.As the dust contamination, electric field concentration in Insulator feet of steel parts, produce intermittent corona discharge, with the increase in the degree of dust contamination, intermittent corona discharge evolution of the corona discharge is sustained, continuous further development of the spark discharge, long-term spark discharges gradually break the glass member adjacent to the inner edge of the steel pin, which spark duration against the glass member and the damage to a certain extent, steel layer is damaged, concentrated Insulator time of occurrence, the location of the multi-chip crushing concentrated.
6 due to mechanical damage caused by spark discharge duration
Tab.6 Damage caused by on-going sparkle
(2) a glass surface is very uneven thermal damage [4] due to the temperature difference.Insulator glass serious the contamination, in the case of damp, deposit the waste material is wetted and becomes conductive to produce a leakage current.Leakage current generated heat to evaporate water on the glass member, formation of localized “dry zone” on the glass surface, and the “dry zone” occur around steel legs.Voltage causes “dry zone” to produce local arcs, local arcs can cause the vitreous prolonged localized uneven heating, thereby causing thermal damage.
12 of August 1, 2016, of a 500 kV line number 69, a number 70 (the same column further return line 70, 71) across the river at two strings of glass Insulator yl tower blew occurs, two groups of long span tower Insulator 11 glass with varying degrees of Insulator blew, wherein up to 16 up to a single string SELF total 140 blew.
The line on February 9, 2004 formally put into operation, with a glass Insulator, and coated PRTV in 2009, the same batch of glass Insulator put into operation a total of 1 632.
FIG 7 blew glass Insulator concentration occurs tower
Tab.7 The tower that glass insulator concentrated self-blast
June 30, 2016, July 3 and July 19, operation and maintenance personnel were normal patrol base for more than two towers across the river and found no case blew Insulator.August 1, when the patrol base tower again found that more than two multi-string Insulator occurred blew.From the inspection results, the above two groups tower glass blew time, mainly in Insulator 20 July 31 July -.
Glass Insulator focus areas from July 1 blew weather conditions ~ July 31st of view, July 1 – July 20 Japan continued rainy weather primarily, July 21 – July 31 shayang region Weather mostly sunny continued, of which 7 19 – 20, there was heavy rain weather.
After investigation, the right side of the tower 69 at about 3 km, some transport vehicles quarries and cement plants each one, quarries and cement plants will pass next to the tower of County Road 69.Due to long-term contamination of dust, Insulator more serious degree of fouling here.
State Power Corporation in Hubei Province Research Institute personnel detector for measuring the pollution level of the replaced glass Insulator, the average density of salt 0.174 mg / cm2, adhesion of ash 2.506 mg / cm2, according QGDW1152.1-2014 “power system pollution classification and external insulation selection AC system – Part 1” level to which the contamination level e.
3.4.A secondary glass Insulator Analysis of the contamination
The focus Insulator blew glass are coated in 2009 PRTV, have not been cleaning during operation and maintenance, the surface area of serious pollution.Tion by the density detecting ESDD show that to achieve the contamination level e Insulator.
FIG 8 the contamination serious glass Insulator
Tab.8 The glass insulator that polluted seriously
Right tower 69 at about 3 km each have a quarry and cement, is a typical source of air pollution.Quarries and cement portion of the vehicle through prefectural road next to the tower 69, dust is very serious, so that relatively high concentrations of air pollutants in the vicinity of the tower 69.Further, since the line number 69-70 Doosan column across Han River, ambient air humidity, so that the contamination Insulator easier; on the other hand, No. 69-70 Insulator coated glass column PRTV in 2009, has been in operation for seven years, PRTV presence of a surface layer and peeling off phenomenon, antifouling properties significantly decreased, in a wet condition more adsorption of dust and other air particulates.Over time, resulting in the contamination No. 69-70 Tower Insulator serious.
No. 69-70 with respect to an adjacent column tower, 69 and 70 across the river, ambient air humidity, and is linear tower; 68 adjacent the tower 71 and relatively far away from the river, and is Strain column, the contamination No. Insulator 69 relative column 70 and lighter Insulator.
3.4.Insulator glass 2 times the contamination Analysis
The glass blew from Insulator “residues hammer” view, broken glass on the residual weight was significantly scaly, preliminary judgment blew the start position near the bottom of the glass iron cap member.
3.4.Glass Insulator blew three times the cause investigation
Insulator glass batch has run nearly 13 years, this very concentrated blew time and place, the larger the number, and the glass blew Insulator “residues hammer” shape point of view, the glass member blew the start position near the bottom of the iron cap, and the head of non-glass pieces, glass does not comply with the law in general Insulator blew, blew can exclude the product itself quality problems caused by.
On the “residual hammer” and has not yet broken glass Insulator Insulator The SELF be carefully examined, (1) did not find any traces against external damage, was the possibility to exclude products against external mechanical stress damage; (2) did not find any evidence of large-frequency arc, the case where no flashover occurs line is the same, it is possible to exclude the possibility of frequency arc initiation Insulator concentration broken glass; (3) have not found within the upper edge of the glass member signs of damage, may preclude the possibility of electrical stress on the mechanical destruction of glass Insulator.
Figure 9 of this SELF glass Insulator “residual hammer”
Tab.9 The residual hammer of glass insulator this time
3.4.Four times Glass Insulator blew Analysis
The SELF Insulator broken glass on glass “residual hammer” showed a scaly, preliminary judgment blew the starting position is located near the bottom glass iron cap member.
69 and the presence of other sources quarries and cement field, over 70 near the tower, so that the contamination severely glass Insulator.The concentrate was blew coated glass Insulator PRTV coating, so long leakage current gradually deteriorates PRTV coating, coating deterioration in wet weather PRTV more easily and quickly the contamination.
July 1 – July 20 incident, the main area sustained rainy weather, especially 19 to 20 days there has been heavy rain, enough water inside the waste material Insulator bell-type surface wet, it becomes and into the conductor a greater leakage current; heat leakage current generated by evaporation of water on the glass member, formation of localized “dry zone” on the glass surface, since the inner surface area Insulator serious pollution such “dry zone” in focus appears steel near the feet, causing the voltage “dry zone” to produce local arcs, caused by prolonged local arcs Insulator glass surface leakage current is very unevenly distributed, so that the local heating vitreous very uneven, resulting in a concentrated period of time, place focus on glass Insulator blew a large number of.
Glass Insulator serious underlying causes of the contamination is concentrated blew.Insulator serious dust contamination of the front glass due to continued rain blew waste within the bell-jar type Insulator wetted surface, so that it becomes conductive and a greater leakage current, the surface leakage current Insulator very uneven distribution, resulting in temperature of the glass surface is very uneven, resulting in a time to focus, glass Insulator large centralized location blew.
Glass Insulator PRTV coated paint tends to deteriorate, deterioration PRTV paint will not only lose due antifouling performance, but also lead Insulator self-cleaning properties deteriorate, resulting in the contamination is more serious Insulator.Thus, more rain, moisture microtopography line region is not recommended porcelain, glass coated PRTV Insulator Coating.Meanwhile, coated PRTV line should strengthen the monitoring and operation and maintenance cleaning efforts, combined with state of the maintenance cycle should continue to do every stop will sweep.
[Reference] (the References)
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[2] Song Lei, Zhang increase, and so Luoling.Effects on the surface of the growth of moss glass Insulator 500 kV AC transmission line [J].High Voltage Engineering, 2014,40 (4): 1038-1044.SONG Lei, ZHANG Fuzeng, LUO Ling, et al.Effect of Surface Moss on Glass Insulator of 500 kV AC Transmission Line [J].High Voltage Engineering, 2014, 40 (4): 1038-1044.
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Analysis of the Concentrated Self-blast Cause of Glass Insulator on 500 kV Transmission Line
HUANG Songquan1, ZHOU Xueming2, HU Danhui2, YAO Yao2, LIU Zhengyun3
(1.State Grid Hubei Electric Power Company, Wuhan Hubei430077, China; 2.State Grid Hubei Electric Power Research Institute, Wuhan Hubei430077, China; 3.Hubei Electric Transmission & Distribution Engineering Company, Wuhan Hubei430077, China)
[Abstract] The concentrated self-blast phenomenon of glass insulator have occurred many times in the country, which seriously affects the application of glass insulator in transmission line.So it is of great significance for taking effective prevention measures after in-depth analysis work base on the self-blast feature of glass insulator.The factor element of concentrated self-blast on glass insu?lator is analyzed in this paper, and the reason of concentrated self-blast is analyzed by connecting with a practical case.The leakage current caused by serious pollution is the main factor element that lead to concentrated self-blast of glass insulator.
[Key words] glass insulator; concentrated self-blast; pollution; leakage current
[CLC] TM216
[Document Code] A
[Article ID] 1006-3986 (2017) 04-0005-04
[Received Date] 2017-03-06
[Author] Huangsong Quan (1966-), male, Hubei Ezhou people, senior engineer.
DOI: 10.19308 / j.hep.2017.04.002