Background technology
The rated voltage of electrification railway contact net work is 25kV, and system maximum operating voltage is 27.5kV.Near contact line, thunderstorm hour occurs, contact line there will be the atmospheric over-voltage substantially exceeding 27.5kV.This very high overvoltage can make insulator arc-over or to puncture and accidents caused, works the mischief to contact net equipment.Atmospheric over-voltage can be divided into lightning induced voltage and direct lightning strike overvoltage.Lightning induced voltage is the acute variation due to electromagnetic field, and electromagnetic coupled produces, direct lightning strike overvoltage be then due to flow through hit the very large lightning current of thing cause.Lightning induced voltage generally can not more than 500kV, therefore endanger maximum to the insulator of 35kV and following electric pressure.Fact proved, for many years, on Minxing, Shanghai power supply station and other regional 35kV circuit, the thunderstruck number of times of insulator reaches more than 40 time.On electrification railway contact net on the administrative circuit of Guangzhou power-feed section, the special administrative circuit of wide dark visitor, the administrative circuit of high ferro section of Nanning Railway Bureau, porcelain insulator and composite insulator also repeatedly suffer lightning impulse, particularly the wide line multitude-Chinese parasol tree section in south in spring in 2014 Super Typhoon and strong convective weather situation under, 54 lightning impulses are recurred in short-term, insulator umbrella punctures, electric discharge burn 19 place, and carrier cable twisted wire multiply is blown.The harm of lightning impulse to contact line causes height concern and the attention of relevant railway department, prevents Lightning Disaster, improves the lightning withstand level of contact line vitals, guarantee that safety of railway traffic is extremely urgent.
The composite insulator that current China electrification railway contact net uses be on high voltage power transmission and transforming circuit use similar electric pressure composite insulator basis on according to iron mark TB/T3199.2-2008 electrification railway contact net insulator Part II: the requirement of bar-shaped composite insulator manufactures and designs, and lightning withstand level is not high.And for electrification railway contact net complex structure, the dense vegetation such as metal netware is many, electromagnetic field intensity is high, Along Railway trees, on the sunny side domatic many, the situation such as tunnel is many, the probability of lightning impulse is much larger than the actual conditions of other high-tension lines, and the composite insulator that specific aim research and development lightning withstand level is higher is significant.
Summary of the invention
The present invention, in order to overcome above-mentioned deficiency of the prior art, provides a kind of rational in infrastructure, easy for installation and electrification railway contact net composite insulator that lightning withstand level is high.
For achieving the above object, solution of the present invention is: a kind of composite insulator of resistance to lightning impulse, comprise plug, the first sheath, the full skirt be located on sheath, high-pressure side gold utensil, earth terminal gold utensil and at least one the first stress cone or the first stress cone group, described first stress cone or the first stress cone group are arranged on high-pressure side gold utensil and/or earth terminal gold utensil and plug junction, and the first stress cone that described first stress cone group was fitted by two cone ends combines.Insulator end gold utensil is the most key position of whole insulator, if this position of lightning overvoltage impact failure, first sheath may be burnt, ftracture and cause plug exposed, and plug burn impaired after can form charing road warp, this charing path is irreversible, along with the continuous extension in charing path, core brittle fracture and accidents caused will be caused.After corresponding external insulation stress cone is set; as lightning impulse voltage act on herein or neighbouring time; stress cone dispersibles lightning current wave head; alleviate lightning current rising steepness; in addition stress cone place increases the thickness of external insulation; can the structural safety of available protecting end metal fitting, improve lightning withstand level and the useful life of insulator.
Preferably, the described composite insulator of resistance to lightning impulse also comprises the second sheath, and the second sheath described in described second sheath is wrapped in two stress cone junctions of stress cone group, and described second sheath is HTV silica gel sheath.HTV silica gel sheath at utmost can reduce the lightning impulse voltage that end metal fitting is subject to, protection end metal fitting.
China's electrifing railway contacting net system maximum operating voltage is 27.5kV, and Composite Insulators lightning withstand level peak value is 310kV, when lightning current is greater than line lightning resisting level, can cause insulator surface flashover.The lightning stroke flashover time, majority was only about 50s, and line-breaker has little time action, and when only having flashover passage to transfer power frequency short circuiting arc to, circuit breaker just can trip.The pass of probability (probability of sustained arc) and field intensity that impulse flashover transfers stable power frequency arc to is:
η=(4.5E
0.75-14) % formula (1-1)
In formula: η-power frequency continued flow builds arc probability
neutral point non-direct grounding system insulator string average field-strength, unit is kV/m, wherein μ e is circuit rated voltage, and unit is kV; Lj is insulator string electrical arc distance, and unit is m.
Calculate (one):
For the FQBSG-25/12-890JHP clavate post composite insulators produced at present and FQXSG-25/160/940HH composite rod insulator with improve after same model composite insulator calculate contrast as follows: (system operating voltage calculates by 27.5kV)
Example one: the FQBSG-25/12-890JHP insulator produced at present, known arcing distance Lj=0.68m, E=27.5/ (2 × 0.68)=20.22/m, is calculated as follows by formula (1-1):
η=(4.5×20.22-14)%=28.90%
Same model insulator after improvement, known arcing distance Lj=0.752m, E=27.5/ (2 × 0.752)=18.22kV/m, is calculated as follows by formula (1-1):
η=(4.5×18.22-14)%=25.68%
Example two: the FQXSG-25/160-940HH insulator produced at present, known arcing distance Lj=0.72m, E=27.5/ (2 × 0.72)=20kV/m, is calculated as follows by formula (1-1):
η=(4.5×20-14)%=28.56%
Same model insulator after improvement, known arcing distance Lj=0.881m, E=27.5/ (2 × 0.881)=15.60kV/m, is calculated as follows by formula (1-1):
η=(4.5×15.6-14)%=21.32%
Result of calculation shows that the probability of sustained arc improving rear insulator reduces by 3.22% and 7.24% respectively, and effectively suppress the generation of stablizing power frequency arc, this is very useful to the safety of insulator under lightning impulse.
Calculate (two):
The one side that the lightning withstand level of Voltage for Insulators on HV Lines is very important is the lightning impulse flashover voltage depending on insulator string, generally insulator string positive polarity lightning impulse flashover voltage is lower than negative polarity, and therefore the flashover voltage of insulator calculates by positive polarity lightning impulse flashover voltage.Its computing formula is:
UI
50=6.3L
d-37.5kV (peak) formula (1-2)
In formula: L
dfor dry arc-over distance, unit is cm.
(example one) is for FQBSG (the NL)-25/12-890JHP insulator after improving:
Know according to formula (1-2): UI
50=6.3 × 75.2-37.5=466.26kV (peak) considers lightning impulse withstand voltage (U again
w1) be generally 90% of flashover voltage, therefore have:
U
W1=466.26×0.9=419.6kV(peak)
(example two) is for FQXSG (the NL)-12/160-940HH insulator after improving
Know according to formula (1-2): UI
50=6.3 × 88.1-37.5=517.53kV (peak) considers lightning impulse withstand voltage (U again
w1) be generally 90% of flashover voltage, therefore have:
U
W1=517.53×0.9=465.77kV(peak)
Result of calculation shows that the lightning impulse withstand voltage innovating the insulator after improving improves 109.6kV and 155.77kV respectively than TB/T3199.2-2008 standard value.
Preferably, the described composite insulator of resistance to lightning impulse also comprises can all pressures shading ring of equalizing voltage, and described shading ring of all pressing is arranged on high-pressure side and/or earth terminal gold utensil.The voltage's distribiuting of insulator is relevant with the direct-to-ground capacitance of self, and the voltage distribution of insulator that direct-to-ground capacitance is large is even, otherwise then uneven.The direct-to-ground capacitance of composite insulator is little, and voltage's distribiuting is uneven, and it is more obvious to raise inhomogeneities with voltage, and arranging after even shading ring can equalizing voltage, weakens the electric field force of parallel direction, is beneficial to and suppresses conducting particles to develop along face, prevent flashover.Gold utensil place maximum field intensity can be reduced simultaneously, reduce electric field distortion degree, be beneficial to and improve the flashover voltage of the insulator and discharge inception voltage, under lightning overvoltage is impacted, electric arc can be attracted in self.Described all pressures shading ring is provided with to be raised; ring set one; ring footpath is parallel to cluster parachute; optimized dimensions is 70% of insulator gamp diameter, does not affect arcing distance, without in-site installation; electric property is good; and the high temperature produced instantaneously can be derived when lightning impulse overvoltage impacts insulator, ensure that insulator temperature rise is in this case no more than ambient temperature 20K, protection insulator is injury-free.
A kind of two insulation composite insulator of resistance to lightning impulse, comprises wire jumper clip and the previously described composite insulator of resistance to lightning impulse, and described wire jumper clip to be arranged between high-pressure side gold utensil and plug on bolt.
The bar-shaped suspended compound insulator of a kind of resistance to lightning impulse, comprise the previously described composite insulator of resistance to lightning impulse and at least one the second stress cone or the second stress cone group, described second stress cone or the second stress cone group are arranged on plug, and the second stress cone that described second stress cone group was fitted by two cone ends combines.
The bar-shaped suspended compound insulator of the resistance to lightning impulse of a kind of two insulation, comprise previously described two insulation composite insulators of resistance to lightning impulse and at least one the second stress cone or the second stress cone group, described wire jumper clip to be arranged between high-pressure side gold utensil and plug on bolt, described second stress cone or the second stress cone group are arranged on plug, and the second stress cone that described second stress cone group was fitted by two cone ends combines.
Beneficial effect:
(1) structural safety of effective protection end metal fitting, improves lightning withstand level and the useful life of insulator;
(2) dynamics of the lightning impulse voltage that end metal fitting is subject to is decreased;
(3) ensure insulator temperature rise be no more than ambient temperature 20K, improve flashover voltage and the discharge inception voltage of insulator;
(4) simple and reasonable, easy for installation.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is explained.
Specific embodiment one:
A kind of composite insulator of resistance to lightning impulse of the present invention, comprises plug 1, first sheath 2, full skirt 3, all presses shading ring 4, high-pressure side gold utensil 51, earth terminal gold utensil 52, first stress cone 6 and the second sheath 8.First sheath 2 is positioned at the outside of plug 1; Full skirt 3 is located on the first sheath 2; First stress cone 6 is provided with two groups, and often group is bored the end by two the first stress cones 6 and is sticked to form, and be located at plug two ends respectively, the first stress cone is external insulation stress cone; All press shading ring 4 between stress cone 6 and high-pressure side gold utensil 51 and/or earth terminal gold utensil 52; Second sheath 8 is HTV silica gel sheath, is located at gold utensil outside.
Specific embodiment two:
A kind of two insulation composite insulator of resistance to lightning impulse of the present invention, comprises plug 1, first sheath 2, full skirt 3, all presses shading ring 4, high-pressure side gold utensil 51, earth terminal gold utensil 52, first stress cone 6 and the second sheath 8.First sheath 2 is positioned at the outside of plug 1; Full skirt 3 is located on the first sheath 2; First stress cone 6 is provided with two groups, and often group is bored the end by two the first stress cones 6 and is sticked to form, and be located at plug two ends respectively, the first stress cone is external insulation stress cone; All press shading ring 4 between stress cone 6 and high-pressure side gold utensil 51 and/or earth terminal gold utensil 52; Wire jumper clip 7 to be arranged between high-pressure side gold utensil 5 and plug 1 on bolt; Second sheath 8 is HTV silica gel sheath, is located at gold utensil outside.
Specific embodiment three:
A kind of composite insulator of resistance to lightning impulse of the present invention, comprises plug 1, first sheath 2, full skirt 3, all presses shading ring 4, high-pressure side gold utensil 51, earth terminal gold utensil 52, first stress cone 6, second stress cone 61 and the second sheath 8.First sheath 2 is positioned at the outside of plug 1; Full skirt 3 is located on the first sheath 2; First stress cone 6 is provided with two groups, often group is bored the end by two the first stress cones 6 and is sticked to form, be located at plug two ends respectively, second stress cone 61 is provided with at least one group, second stress cone 61 is arranged on plug, the second stress cone that often group was fitted by two cone ends combines, and the first stress cone 6 and the second stress cone 61 are all external insulation stress cone; All press shading ring 4 between stress cone 6 and high-pressure side gold utensil 51 and/or earth terminal gold utensil 52; Second sheath 8 is HTV silica gel sheath, is located at gold utensil outside.
Specific embodiment four:
A kind of composite insulator of resistance to lightning impulse of the present invention, comprises plug 1, first sheath 2, full skirt 3, all presses shading ring 4, high-pressure side gold utensil 51, earth terminal gold utensil 52, first stress cone 6, second stress cone 61, wire jumper clip 7 and the second sheath 8.First sheath 2 is positioned at the outside of plug 1; Full skirt 3 is located on the first sheath 2; First stress cone 6 is provided with two groups, often group is bored the end by two the first stress cones 6 and is sticked to form, be located at plug two ends respectively, second stress cone 61 is provided with at least one group, second stress cone 61 is arranged on plug, the second stress cone that often group was fitted by two cone ends combines, and the first stress cone 6 and the second stress cone 61 are all external insulation stress cone; All press shading ring 4 between stress cone 6 and high-pressure side gold utensil 51 and/or earth terminal gold utensil 52; Wire jumper clip 7 to be arranged between high-pressure side gold utensil 5 and plug 1 on bolt; Second sheath 8 is HTV silica gel sheath, is located at gold utensil outside.