CN104392055B - Combined type composite material shaft tower lightning protection Optimization Design - Google Patents

Abstract

The invention discloses a kind of combined type composite material shaft tower lightning protection Optimization Design: comprise 1, obtain tower structure information; 2, set up the surge impedance model of ground wire cross-arm and tower body, set up the segmentation lumped inductance model of down conductor; 3, determine according to tower head structure the path that flashover may occur, set up the insulation flashover model based on first inducing defecation by enema and suppository; 4, the stake resistance model considering lightning current shock effect is set up; 5, according to above-mentioned several model, the lightning stroke simulation model of integral basis complex pole tower is connected to form, 6, the calculating of lightning withstand level and tripping rate with lightning strike, 7, iterative computation and parameter upgrade.The present invention updates the geometry of composite material pole tower by the means of iteration, thus improves the Technical Economy of composite material pole tower under the prerequisite ensureing Lightning performance.

Description

Combined type composite material shaft tower lightning protection Optimization Design

Technical field

The present invention relates to transmission line of electricity anti-thunder technical field, refer to a kind of combined type composite material shaft tower lightning protection Optimization Design particularly.

Background technology

Along with the rapid expansion of electrical network scale, power construction consumes the resources such as increasing soil and iron and steel.For a long time, widely used steel tower in transmission line of electricity, quality weight, transport and assembling inconvenience all considerably increase construction cost and the O&M cost of circuit.The plurality of advantages such as compound substance has that electrical insulating property is good, intensity is high, corrosion-resistant, environmental friendliness, adopt compound substance to make tower head, can improve tower head magnetic distribution, greatly promote insulating property.Substitute steel with compound substance, power transmission line corridor width can be reduced, reduce steel use amount.

Compound substance has many-sided advantage, and the shaft tower made and common steel tower have relatively big difference, Lightning performance and shaft tower geometry closely related.The project organization of existing combined type composite material shaft tower is generally be tending towards conservative mentality of designing, namely pay the utmost attention to guarantee Lightning performance, but in this case, tower structure size is reasonable not, increase the consumption of compound substance, thus increase line construction cost.

List of references: People's Republic of China's power industry standard " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination ";

" research of 110kV transmission line of electricity composite material pole tower attribute testing " Hu Yi, Liu front yard, Liu Kai, Deng Shicong, Li Hanming, Hu Guangsheng High-Voltage Technology the 37th volume the 4th phase in 2011;

" research based on the line insulation flashover criterion of continuous leader " Xiao Ping, Wang Buoyant, Huang Fuyong, Zhou Weihua, kingdom's profit, Xiong Jingwen, Anyi, electric power network technique 36 volume o. 11ths in 2012;

" the tower grounding body impulse earthed resistance computation model based on ATP-EMTP " xuwei, Liu Xun, Huang Weichao, power construction the 31st volume the 5th phase in 2010;

List of references: Li Xiaolan, Yin little Gen, Yu Renshan, He Junjia " calculating based on the back flash-over rate of improved EGM " periodical " High-Voltage Technology " 32 volumes the 3rd phase in 2006

Summary of the invention

Object of the present invention will provide a kind of combined type composite material shaft tower lightning protection Optimization Design exactly, this method updates the geometry of composite material pole tower by the means of iteration, thus improves the Technical Economy of composite material pole tower under the prerequisite ensureing Lightning performance.

For realizing this object, the combined type composite material shaft tower lightning protection Optimization Design designed by the present invention, it is characterized in that, it comprises the steps:

Step 1: the length l obtaining the ground wire cross-arm of combined type composite material shaft tower from the modular design figure of combined type composite material shaft tower _g, ground wire cross-arm radius r _a, first-phase wire is to the air gap distance D of down conductor ₁, second-phase wire is to the air gap distance D of down conductor ₂, third phase wire is to the air gap distance D of down conductor ₃, ground wire cross-arm is to topping wire cross-arm vertical interval h ₁, topping wire cross-arm is to the vertical interval h of lower layer conductor cross-arm ₂, steel pipe pole height h ₃, the distance l of ground wire on first-phase wire to homonymy ground wire cross-arm ₁, first-phase wire is to the distance l of the third phase wire of homonymy ₂inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains composite impact flashover property parameter, the air impulse sparkover characteristics parameter of the box-like composite material pole tower of above-mentioned classical group, and inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains down conductor unit length inductance value L ₀;

Step 2: the wave impedance Z being calculated ground wire cross-arm by following formula 1 _a;

$Z_A=60\ln \left(\frac{{2h}_A}{r_A}\right)---\left(1\right)$

Wherein, r _afor the radius of ground wire cross-arm, h _afor the height of ground wire cross-arm, i.e. h _a=h ₁+ h ₂+ h ₃;

The wave impedance Z of steel pipe pole is calculated by following formula 2 _t;

$Z_T=60(\ln \frac{2\sqrt{2}{h}_3}{r_T}-1)---\left(2\right)$

Wherein, h ₃for the height of steel pipe pole, r _tfor the tip section of steel pole pipe and the average of bottom section radius;

The position of described down conductor residing for topping wire cross-arm is that boundary is divided into interconnective upper and lower two parts, the inductance value L of upper part down conductor _g1calculated by following formula 3:

L _g1＝L ₀*h ₁(3)

Wherein, L ₀for down conductor unit length inductance value, h ₁for ground wire cross-arm is to topping wire cross-arm vertical interval, the i.e. length of upper part down conductor;

The inductance value L of lower part down conductor _g2calculated by following formula 4:

L _g2＝L ₀*h ₂(4)

Wherein, L ₀for down conductor unit length inductance value, h ₂for topping wire cross-arm is to the vertical interval of lower layer conductor cross-arm, i.e. the length of lower part down conductor;

The wave impedance Z of above-mentioned ground wire cross-arm _a, steel pipe pole wave impedance Z _twith the inductance value L of upper part down conductor _g1and the inductance value L of lower part down conductor _g2constitute the lightning stroke simulation model of ground wire cross-arm, steel pipe pole and down conductor;

Step 3: the guide obtained in combined type composite material shaft tower clearance for insulation by following formula 5 develops length x, wherein combined type composite material shaft tower clearance for insulation L is the distance D between first-phase wire and down conductor ₁, distance D between second-phase wire and down conductor ₂, distance D between third phase wire and down conductor ₃, the distance l of ground wire on first-phase wire to homonymy ground wire cross-arm ₁with the distance l of first-phase wire to the third phase wire of homonymy ₂, likely there is gap flashover in the gap in above-mentioned step corresponding to each distance;

$\frac{\mathrm{dx}}{\mathrm{dt}}=\mathrm{ku}\left(t\right)(\frac{u\left(t\right)}{L-x}-E_0)---\left(5\right)$

Wherein, t is the time of the guide's development in combined type composite material shaft tower clearance for insulation, and k is the experience factor of impulsive discharge experimental result matching gained, E ₀for the field intensity that combined type composite material shaft tower clearance for insulation L guide is initial, u (t) terminates the magnitude of voltage of interior each time period for combined type composite material shaft tower clearance for insulation L starts extremely generation flashover or simulation thunderbolt in combined type composite material shaft tower simulation thunderbolt, this magnitude of voltage obtains by extracting in existing combined type composite material shaft tower thunderbolt simulation software, the experience factor k of above-mentioned impulsive discharge experimental result matching gained and the initial field intensity E of combined type composite material shaft tower clearance for insulation L guide ₀the existing method in document " research based on the line insulation flashover criterion of continuous leader " is utilized to calculate according to the composite impact flashover property parameter of the box-like composite material pole tower of the classical group obtained in step 1, air impulse sparkover characteristics parameter, dx/dt is the guide's speed of development in composite material pole tower clearance for insulation, and above-mentioned formula 5 forms the insulation flashover model of combined type composite material shaft tower;

Step 4: obtain the grounding resistance R of combined type composite material shaft tower under lightning impulse effect by following formula 6 _ch;

$R_{\mathrm{ch}}=\frac{R_0}{\sqrt{1+I/I_g}}---\left(6\right)$

Wherein, R _ofor the grounding resistance of combined type composite material shaft tower under power current, I is the dash current amplitude that lightning impulse flows by action crosses box-like composite material pole tower grounding body, I _gthe minimum current value making soil that ionization occur, above-mentioned R _ofor the representative value recorded in list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination ", I _gfor the representative value recorded in list of references " the tower grounding body impulse earthed resistance computation model based on ATP-EMTP ", I is the value calculated in real time by existing combined type composite material shaft tower thunderbolt simulation software, and above-mentioned formula 6 forms combined type composite material shaft tower lightning impulse stake resistance model;

Step 5: the insulation flashover model of above-mentioned ground wire cross-arm lightning stroke simulation model, steel pipe pole lightning stroke simulation model, down conductor lightning stroke simulation model, combined type composite material shaft tower is connected combination with combined type composite material shaft tower lightning impulse stake resistance model according to the version of the modular design figure of combined type composite material shaft tower in step 1, namely forms the lightning stroke simulation model of integral basis composite material pole tower;

Step 6: use ATP-EMTP simulation software to calculate counterattack lightning withstand level and the shielding lightning withstand level of integral basis composite material pole tower by the lightning stroke simulation model of integral basis composite material pole tower;

Step 7: utilize above-mentioned counterattack lightning withstand level to calculate counterattack trip-out rate BSTOR by following formula 7 _c:

BSTOR _c＝NgP ₁η(7)

Wherein, described N is thunderbolt number of times in every 100 kilometers of line corridor; calculate by reference to given method in document " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination "; described g be inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtain hit bar rate, described P ₁for amplitude of lightning current exceedes the probability of counterattack lightning withstand level, this probability is calculated according to the existing method of list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " by the counterattack lightning withstand level obtained in step 6, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Above-mentioned shielding lightning withstand level is utilized to calculate back flash-over rate SFTOR by following formula 8 _c:

${\mathrm{SFTOR}}_c=\frac{N_d}{10}\left(\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{\∫}_{I_{2k}}^{I_{s\max k}}{P}^{\′}\left(I\right)D_k\left(I\right)\mathrm{dI}\right)\mathrm{\η}---\left(8\right)$

Back flash-over rate SFTOR _ccalculate according to the electric geometry method improved, total back flash-over rate is each phase back flash-over rate sum, N _dfor given CG lightning density value, I _2kfor kth phase shielding lightning withstand level, wherein k is 1 or 2 or 3, and this kth phase shielding lightning withstand level is that ATP-EMTP simulation software calculates by existing manner, I _smaxkfor the mutually maximum around shocking electric current of kth, wherein k is 1 or 2 or 3, and the mutually maximum around shocking electric current of this kth is that wire coordinate corresponding in the electric geometry method improved and ground line coordinates calculating are obtained, P ^'(I) be amplitude of lightning current probability distribution density; it is the derivative of amplitude of lightning current probability distribution function P (I); amplitude of lightning current probability distribution function P (I) is determined, D by list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " _kfor kth phase conductor under corresponding lightning current exposes arc projector distance, under this corresponding lightning current, kth phase conductor exposure arc projector distance is obtained according to the existing mode in the electric geometry method improved, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Following formula 9 is utilized to calculate the final tripping rate with lightning strike of shaft tower:

LTOR _c＝BSTOR _c+SFTOR _c(9)

Namely the tripping rate with lightning strike that shaft tower is final equals counterattack trip-out rate and back flash-over rate sum;

Step 8: compare the tripping rate with lightning strike LTOR that shaft tower is final _cwith the set quota LTOR about tripping rate with lightning strike in list of references " 110 (66) kV ~ 500kV overhead transmission line operations specification " _rsize;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe less than the set quota LTOR of described tripping rate with lightning strike _rtime, tower structure parameter safety is described, by reducing the length l of the ground wire cross-arm of combined type composite material shaft tower _g, first-phase wire is to the air gap distance D of down conductor ₁, second-phase wire is to the air gap distance D of down conductor ₂, third phase wire is to the air gap distance D of down conductor ₃, and adjust ground wire cross-arm to topping wire cross-arm vertical interval h ₁, topping wire cross-arm is to the vertical interval h of lower layer conductor cross-arm ₂, steel pipe pole height h ₃, achieving the tripping rate with lightning strike LTORc simultaneously making tower final at the consumption reducing compound substance increases;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe greater than the set quota LTOR of described tripping rate with lightning strike _rtime, by increasing the length l of the ground wire cross-arm of combined type composite material shaft tower _g, first-phase wire is to the air gap distance D of down conductor ₁, second-phase wire is to the air gap distance D of down conductor ₂, third phase wire is to the air gap distance D of down conductor ₃improve the dielectric level of combined type composite material shaft tower and reduce shielding angle, thus reducing the final tripping rate with lightning strike LTOR of shaft tower _cvalue.

Beneficial effect of the present invention:

The combined type composite material shaft tower thunderbolt phantom that the present invention proposes, by obtaining tower structure information and according to the insulation flashover model of above method establishment ground wire cross-arm lightning stroke simulation model, steel pipe pole lightning stroke simulation model, down conductor lightning stroke simulation model, combined type composite material shaft tower and combined type composite material shaft tower lightning impulse stake resistance model.The realistic model set up as stated above more will can reflect the situation that composite material pole tower is struck by lightning exactly, grasps complex pole tower lightning protection properties provide foundation for electrical network operation maintenance personnel.Meanwhile, said method updates the geometry of composite material pole tower by the means of iteration, thus improves the Technical Economy of composite material pole tower under the prerequisite ensureing Lightning performance.

Accompanying drawing explanation

Fig. 1 is combined type composite material shaft tower tower head and full tower schematic diagram;

Fig. 2 is the side view of ground wire cross-arm part in Fig. 1;

Wherein, wherein, 1-ground wire cross-arm, 2-first-phase wire, 3-down conductor, 4-second-phase wire, 5-third phase wire, 6-topping wire cross-arm, 7-lower layer conductor cross-arm, 8-steel pipe pole, 9-ground wire.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:

A kind of combined type composite material shaft tower lightning protection Optimization Design, it comprises the steps:

Step 1: the length l obtaining the ground wire cross-arm 1 of combined type composite material shaft tower from the modular design figure of combined type composite material shaft tower _g, ground wire cross-arm 1 radius r _a, first-phase wire 2 is to the air gap distance D of down conductor 3 ₁, second-phase wire 4 is to the air gap distance D of down conductor 3 ₂, third phase wire 5 is to the air gap distance D of down conductor 3 ₃, ground wire cross-arm 1 to topping wire cross-arm 6 vertical interval h ₁, topping wire cross-arm 6 is to the vertical interval h of lower layer conductor cross-arm 7 ₂, steel pipe pole 8 height h ₃, the distance l of ground wire 9 on first-phase wire 2 to homonymy ground wire cross-arm 1 ₁, first-phase wire 2 is to the distance l of the third phase wire 5 of homonymy ₂inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains composite impact flashover property parameter, the air impulse sparkover characteristics parameter of the box-like composite material pole tower of above-mentioned classical group, and inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains down conductor unit length inductance value L ₀, as illustrated in fig. 1 and 2;

Step 2: the wave impedance Z being calculated ground wire cross-arm 1 by following formula 1 _a;

$Z_A=60\ln \left(\frac{{2h}_A}{r_A}\right)---\left(1\right)$

Wherein, r _afor the radius of ground wire cross-arm 1, h _afor the height of ground wire cross-arm 1, i.e. h _a=h ₁+ h ₂+ h ₃;

The wave impedance Z of steel pipe pole 8 is calculated by following formula 2 _t;

$Z_T=60(\ln \frac{2\sqrt{2}{h}_3}{r_T}-1)---\left(2\right)$

Wherein, h ₃for the height of steel pipe pole 8, r _tfor the tip section of steel pole pipe 8 and the average of bottom section radius;

The position of described down conductor 3 residing for topping wire cross-arm 6 is that boundary is divided into interconnective upper and lower two parts, the inductance value L of upper part down conductor 3 _g1calculated by following formula 3, the inductance value L of lower part down conductor 3 _g2calculated by following formula 4;

L _g1＝L ₀*h ₁(3)

Wherein, L ₀for down conductor unit length inductance value, h ₁for ground wire cross-arm 1 to topping wire cross-arm 6 vertical interval, i.e. the length of upper part down conductor 3;

L _g2＝L ₀*h ₂(4)

Wherein, L ₀for down conductor unit length inductance value, h ₂for topping wire cross-arm 6 is to the vertical interval of lower layer conductor cross-arm 7, the i.e. length of lower part down conductor 3;

The wave impedance Z of above-mentioned ground wire cross-arm 1 _a, steel pipe pole 8 wave impedance Z _twith the inductance value L of upper part down conductor 3 _g1and the inductance value L of lower part down conductor 3 _g2constitute the lightning stroke simulation model of ground wire cross-arm 1, steel pipe pole 8 and down conductor 3;

Step 3: the guide obtained in combined type composite material shaft tower clearance for insulation by following formula 5 develops length x, wherein combined type composite material shaft tower clearance for insulation L is the distance D between first-phase wire 2 and down conductor 3 ₁, distance D between second-phase wire 4 and down conductor 3 ₂, distance D between third phase wire 5 and down conductor 3 ₃, the distance l of ground wire 9 on first-phase wire 2 to homonymy ground wire cross-arm 1 ₁with the distance l of first-phase wire 2 to the third phase wire 5 of homonymy ₂, likely there is gap flashover in the gap in above-mentioned step corresponding to each distance;

$\frac{\mathrm{dx}}{\mathrm{dt}}=\mathrm{ku}\left(t\right)(\frac{u\left(t\right)}{L-x}-E_0)---\left(5\right)$

Wherein, t is the time of the guide's development in combined type composite material shaft tower clearance for insulation, and k is the experience factor of impulsive discharge experimental result matching gained, E ₀for the field intensity that combined type composite material shaft tower clearance for insulation L guide is initial, u (t) terminates the magnitude of voltage of interior each time period for combined type composite material shaft tower clearance for insulation L starts extremely generation flashover or simulation thunderbolt in combined type composite material shaft tower simulation thunderbolt, this magnitude of voltage obtains by extracting in existing combined type composite material shaft tower thunderbolt simulation software, the experience factor k of above-mentioned impulsive discharge experimental result matching gained and the initial field intensity E of combined type composite material shaft tower clearance for insulation L guide ₀the existing method in document " research based on the line insulation flashover criterion of continuous leader " is utilized to calculate according to the composite impact flashover property parameter of the box-like composite material pole tower of the classical group obtained in step 1, air impulse sparkover characteristics parameter, dx/dt is the guide's speed of development in composite material pole tower clearance for insulation, and above-mentioned formula 5 forms the insulation flashover model of combined type composite material shaft tower;

Step 4: obtain the grounding resistance R of combined type composite material shaft tower under lightning impulse effect by following formula 6 _ch;

$R_{\mathrm{ch}}=\frac{R_0}{\sqrt{1+I/I_g}}---\left(6\right)$

Wherein, R _ofor the grounding resistance of combined type composite material shaft tower under power current, I is the dash current amplitude that lightning impulse flows by action crosses box-like composite material pole tower grounding body, I _gthe minimum current value making soil that ionization occur, above-mentioned R _ofor the representative value recorded in list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination ", I _gfor the representative value recorded in list of references " the tower grounding body impulse earthed resistance computation model based on ATP-EMTP ", I is the value calculated in real time by existing combined type composite material shaft tower thunderbolt simulation software, and above-mentioned formula 6 forms combined type composite material shaft tower lightning impulse stake resistance model;

Step 5: the insulation flashover model of above-mentioned ground wire cross-arm 1 lightning stroke simulation model, steel pipe pole 8 lightning stroke simulation model, down conductor 3 lightning stroke simulation model, combined type composite material shaft tower is connected combination with combined type composite material shaft tower lightning impulse stake resistance model according to the version of the modular design figure of combined type composite material shaft tower in step 1, namely forms the lightning stroke simulation model of integral basis composite material pole tower;

Step 6: use ATP-EMTP simulation software to calculate counterattack lightning withstand level and the shielding lightning withstand level of integral basis composite material pole tower by the lightning stroke simulation model of integral basis composite material pole tower;

Step 7: utilize above-mentioned counterattack lightning withstand level to calculate counterattack trip-out rate BSTOR by following formula 7 _c:

BSTOR _c＝NgP ₁η(7)

Wherein, described N is thunderbolt number of times in every 100 kilometers of line corridor; calculate by reference to given method in document " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination "; described g be inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtain hit bar rate, described P ₁for amplitude of lightning current exceedes the probability of counterattack lightning withstand level, this probability is calculated according to the existing method of list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " by the counterattack lightning withstand level obtained in step 6, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Above-mentioned shielding lightning withstand level is utilized to calculate back flash-over rate SFTOR by following formula 8 _c:

${\mathrm{SFTOR}}_c=\frac{N_d}{10}\left(\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{\∫}_{I_{2k}}^{I_{s\max k}}{P}^{\′}\left(I\right)D_k\left(I\right)\mathrm{dI}\right)\mathrm{\η}---\left(8\right)$

Back flash-over rate SFTOR _ccalculate according to the electric geometry method (EGM) improved, total back flash-over rate is each phase back flash-over rate sum, N _dfor given CG lightning density value, I _2kfor kth phase shielding lightning withstand level, wherein k is 1 or 2 or 3, and this kth phase shielding lightning withstand level is that ATP-EMTP simulation software calculates by existing manner, I _smaxkfor the mutually maximum around shocking electric current of kth; wherein k is 1 or 2 or 3; the mutually maximum around shocking electric current of this kth is that wire coordinate corresponding in the electric geometry method improved and ground line coordinates calculating are obtained; P ' (I) is amplitude of lightning current probability distribution density; it is the derivative of amplitude of lightning current probability distribution function P (I); amplitude of lightning current probability distribution function P (I) is determined, D by list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " _kfor kth phase conductor under corresponding lightning current exposes arc projector distance, under this corresponding lightning current, kth phase conductor exposure arc projector distance is obtained according to the existing mode in the electric geometry method improved, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Following formula 9 is utilized to calculate the final tripping rate with lightning strike of shaft tower:

LTOR _c＝BSTOR _c+SFTOR _c(9)

Namely the tripping rate with lightning strike that shaft tower is final equals counterattack trip-out rate and back flash-over rate sum;

Step 8: compare the tripping rate with lightning strike LTOR that shaft tower is final _cwith the set quota LTOR about tripping rate with lightning strike in list of references " 110 (66) kV ~ 500kV overhead transmission line operations specification " _rsize;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe less than the set quota LTOR of described tripping rate with lightning strike _rtime, tower structure parameter safety is described, by reducing the length l of the ground wire cross-arm 1 of combined type composite material shaft tower _g, first-phase wire 2 is to the air gap distance D of down conductor 3 ₁, second-phase wire 4 is to the air gap distance D of down conductor 3 ₂, third phase wire 5 is to the air gap distance D of down conductor 3 ₃, and adjust ground wire cross-arm 1 to topping wire cross-arm 6 vertical interval h ₁, topping wire cross-arm 6 is to the vertical interval h of lower layer conductor cross-arm 7 ₂, steel pipe pole 8 height h ₃, achieving the tripping rate with lightning strike LTORc simultaneously making tower final at the consumption reducing compound substance increases;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe greater than the set quota LTOR of described tripping rate with lightning strike _rtime, by increasing the length l of the ground wire cross-arm 1 of combined type composite material shaft tower _g, first-phase wire 2 is to the air gap distance D of down conductor 3 ₁, second-phase wire 4 is to the air gap distance D of down conductor 3 ₂, third phase wire 5 is to the air gap distance D of down conductor 3 ₃improve the dielectric level of combined type composite material shaft tower and reduce shielding angle, thus reducing the final tripping rate with lightning strike LTOR of shaft tower _cvalue, during geometric parameter value first according to common steel tower, the dielectric strength of composite material pole tower has higher nargin.

In technique scheme, in described step 7, thunderbolt times N=N in every 100 kilometers of given line corridor _g* (b+4h)/10, wherein b is the spacing of composite material pole tower two lightning conducters, and h is the average height of composite material pole tower lightning conducter.Described given CG lightning density value N _dbe 2.78 times/km ²* year.

Before adjustment parameter, the thought of control variate method need be utilized, understand each variable to LTOR _cimpact, thus be convenient to hold the variation range of parameter adjustment.Until LTOR _cbe slightly less than LTOR _rtime, the geometric parameter of composite material pole tower can meet the needs of lightning protection, and geometric parameter is now the structural parameters of lightning protection optimum.

By continuous iterative computation, can be met the optimum geometric parameter that lightning protection needs, corresponding shaft tower is minimum to compound substance consumption, and Technical Economy is the highest.The present invention be applicable to 110kV single loop " on " font combined type composite material shaft tower, be also applicable to the combined type composite material shaft tower of other other versions of electric pressure.

The content that this instructions is not described in detail belongs to the known prior art of professional and technical personnel in the field.

Claims (3)

1. a combined type composite material shaft tower lightning protection Optimization Design, it is characterized in that, it comprises the steps:

Step 1: the length l obtaining the ground wire cross-arm (1) of combined type composite material shaft tower from the modular design figure of combined type composite material shaft tower _g, ground wire cross-arm (1) radius r _a, first-phase wire (2) is to the air gap distance D of down conductor (3) ₁, second-phase wire (4) is to the air gap distance D of down conductor (3) ₂, third phase wire (5) is to the air gap distance D of down conductor (3) ₃, ground wire cross-arm (1) is to topping wire cross-arm (6) vertical interval h ₁, topping wire cross-arm (6) is to the vertical interval h of lower layer conductor cross-arm (7) ₂, steel pipe pole (8) height h ₃, first-phase wire (2) is to the distance l of the upper ground wire (9) of homonymy ground wire cross-arm (1) ₁, first-phase wire (2) is to the distance l of the third phase wire (5) of homonymy ₂inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains composite impact flashover property parameter, the air impulse sparkover characteristics parameter of the box-like composite material pole tower of above-mentioned classical group, and inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains down conductor unit length inductance value L ₀;

Step 2: the wave impedance Z being calculated ground wire cross-arm (1) by following formula 1 _a;

$Z_A=60\ln \left(\frac{2h_A}{r_A}\right)---\left(1\right)$

Wherein, r _afor the radius of ground wire cross-arm (1), h _afor the height of ground wire cross-arm (1), i.e. h _a=h ₁+ h ₂+ h ₃;

The wave impedance Z of steel pipe pole (8) is calculated by following formula 2 _t;

$Z_T=60(\ln \frac{2\sqrt{2}{h}_3}{r_T}-1)---\left(2\right)$

Wherein, h ₃for the height of steel pipe pole (8), r _tfor the tip section of steel pole pipe (8) and the average of bottom section radius;

The position of described down conductor (3) residing for topping wire cross-arm (6) is that boundary is divided into interconnective upper and lower two parts, the inductance value L of upper part down conductor (3) _g1calculated by following formula 3;

L _g1＝L ₀*h ₁(3)

Wherein, L ₀for down conductor unit length inductance value, h ₁for ground wire cross-arm (1) is to topping wire cross-arm (6) vertical interval, i.e. the length of upper part down conductor (3);

The inductance value L of lower part down conductor (3) _g2calculated by following formula 4:

L _g2＝L ₀*h ₂(4)

Wherein, L ₀for down conductor unit length inductance value, h ₂for topping wire cross-arm (6) is to the vertical interval of lower layer conductor cross-arm (7), i.e. the length of lower part down conductor (3);

The wave impedance Z of above-mentioned ground wire cross-arm (1) _a, steel pipe pole (8) wave impedance Z _twith the inductance value L of upper part down conductor (3) _g1and the inductance value L of lower part down conductor (3) _g2constitute the lightning stroke simulation model of ground wire cross-arm (1) lightning stroke simulation model, steel pipe pole (8) lightning stroke simulation model and down conductor (3);

Step 3: the guide obtained in combined type composite material shaft tower clearance for insulation by following formula 5 develops length x, wherein combined type composite material shaft tower clearance for insulation L is the distance D between first-phase wire (2) and down conductor (3) ₁, distance D between second-phase wire (4) and down conductor (3) ₂, distance D between third phase wire (5) and down conductor (3) ₃, first-phase wire (2) is to the distance l of the upper ground wire (9) of homonymy ground wire cross-arm (1) ₁with the distance l of first-phase wire (2) to the third phase wire (5) of homonymy ₂, likely there is gap flashover in the gap in above-mentioned step corresponding to each distance;

$\frac{\mathrm{dx}}{\mathrm{dt}}=\mathrm{ku}\left(t\right)[\frac{u\left(t\right)}{L-x}-E_0]---\left(5\right)$

Wherein, t is the time of the guide's development in combined type composite material shaft tower clearance for insulation, and k is the experience factor of impulsive discharge experimental result matching gained, E ₀for the field intensity that combined type composite material shaft tower clearance for insulation L guide is initial, u (t) terminates the magnitude of voltage of interior each time period for combined type composite material shaft tower clearance for insulation L starts extremely generation flashover or simulation thunderbolt in combined type composite material shaft tower simulation thunderbolt, and this magnitude of voltage obtains by extracting in existing combined type composite material shaft tower thunderbolt simulation software; The experience factor k of above-mentioned impulsive discharge experimental result matching gained and the initial field intensity E of combined type composite material shaft tower clearance for insulation L guide ₀, utilize the existing method in document " research based on the line insulation flashover criterion of continuous leader " to calculate according to the composite impact flashover property parameter of the box-like composite material pole tower of the classical group obtained in step 1, air impulse sparkover characteristics parameter; Dx/dt is the guide's speed of development in composite material pole tower clearance for insulation, and above-mentioned formula 5 forms the insulation flashover model of combined type composite material shaft tower;

Step 4: obtain the grounding resistance R of combined type composite material shaft tower under lightning impulse effect by following formula 6 _ch;

$R_{\mathrm{ch}}=\frac{R_0}{\sqrt{1+I/I_g}}---\left(6\right)$

Wherein, R _ofor the grounding resistance of combined type composite material shaft tower under power current, I is the dash current amplitude that lightning impulse flows by action crosses box-like composite material pole tower grounding body, I _gthe minimum current value making soil that ionization occur, above-mentioned R _ofor the representative value recorded in list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination ", I _gfor the representative value recorded in list of references " the tower grounding body impulse earthed resistance computation model based on ATP-EMTP ", I is the value calculated in real time by existing combined type composite material shaft tower thunderbolt simulation software, and above-mentioned formula 6 forms combined type composite material shaft tower lightning impulse stake resistance model;

Step 5: the insulation flashover model of above-mentioned ground wire cross-arm (1) lightning stroke simulation model, steel pipe pole (8) lightning stroke simulation model, down conductor (3) lightning stroke simulation model, combined type composite material shaft tower is connected combination with combined type composite material shaft tower lightning impulse stake resistance model according to the version of the modular design figure of combined type composite material shaft tower in step 1, namely forms the lightning stroke simulation model of integral basis composite material pole tower;

Step 6: use ATP-EMTP simulation software to calculate counterattack lightning withstand level and the shielding lightning withstand level of integral basis composite material pole tower by the lightning stroke simulation model of integral basis composite material pole tower;

Step 7: utilize above-mentioned counterattack lightning withstand level to calculate counterattack trip-out rate BSTOR by following formula 7 _c:

BSTOR _c＝NgP ₁η(7)

Wherein, described N is thunderbolt number of times in every 100 kilometers of line corridor; calculate by reference to given method in document " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination "; described g be inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtain hit bar rate, described P ₁for amplitude of lightning current exceedes the probability of counterattack lightning withstand level, this probability is calculated according to the existing method of list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " by the counterattack lightning withstand level obtained in step 6, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Above-mentioned shielding lightning withstand level is utilized to calculate back flash-over rate SFTOR by following formula 8 _c:

${\mathrm{SFTOR}}_c=\frac{N_d}{10}\left(\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{\∫}_{I_{2k}}^{I_{\text{s max k}}}{P}^{\′}\left(I\right)D_k\left(I\right)\mathrm{dI}\right)\mathrm{\η}---\left(8\right)$

Back flash-over rate SFTOR _ccalculate according to the electric geometry method improved, total back flash-over rate is each phase back flash-over rate sum, N _dfor given CG lightning density value, I _2kfor kth phase shielding lightning withstand level, wherein k is 1 or 2 or 3, and this kth phase shielding lightning withstand level is that ATP-EMTP simulation software calculates by existing manner, I _smaxkfor the mutually maximum around shocking electric current of kth; wherein k is 1 or 2 or 3; the mutually maximum around shocking electric current of this kth is that wire coordinate corresponding in the electric geometry method improved and ground line coordinates calculating are obtained; P ' (I) is amplitude of lightning current probability distribution density; it is the derivative of amplitude of lightning current probability distribution function P (I); amplitude of lightning current probability distribution function P (I) is determined, D by list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " _kfor kth phase conductor under corresponding lightning current exposes arc projector distance, under this corresponding lightning current, kth phase conductor exposure arc projector distance is obtained according to the existing mode in the electric geometry method improved, and described η is the probability of sustained arc that inquiry list of references " overvoltage protection of DL/T6201997 alternating-current electric device and Insulation Coordination " obtains;

Following formula 9 is utilized to calculate the final tripping rate with lightning strike of shaft tower:

LTOR _c＝BSTOR _c+SFTOR _c(9)

Namely the tripping rate with lightning strike that shaft tower is final equals counterattack trip-out rate and back flash-over rate sum;

Step 8: compare the tripping rate with lightning strike LTOR that shaft tower is final _cwith the set quota LTOR about tripping rate with lightning strike in list of references " 110 (66) kV ~ 500kV overhead transmission line operations specification " _rsize;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe less than the set quota LTOR of described tripping rate with lightning strike _rtime, tower structure parameter safety is described, by reducing the length l of the ground wire cross-arm (1) of combined type composite material shaft tower _g, first-phase wire (2) is to the air gap distance D of down conductor (3) ₁, second-phase wire (4) is to the air gap distance D of down conductor (3) ₂, third phase wire (5) is to the air gap distance D of down conductor (3) ₃, and adjust ground wire cross-arm (1) to topping wire cross-arm (6) vertical interval h ₁, topping wire cross-arm (6) is to the vertical interval h of lower layer conductor cross-arm (7) ₂, steel pipe pole (8) height h ₃, achieving the tripping rate with lightning strike LTORc simultaneously making tower final at the consumption reducing compound substance increases;

As the tripping rate with lightning strike LTOR that shaft tower is final _cbe greater than the set quota LTOR of described tripping rate with lightning strike _rtime, by increasing the length l of the ground wire cross-arm (1) of combined type composite material shaft tower _g, first-phase wire (2) is to the air gap distance D of down conductor (3) ₁, second-phase wire (4) is to the air gap distance D of down conductor (3) ₂, third phase wire (5) is to the air gap distance D of down conductor (3) ₃improve the dielectric level of combined type composite material shaft tower and reduce shielding angle, thus reducing the final tripping rate with lightning strike LTOR of shaft tower _cvalue.

2. combined type composite material shaft tower lightning protection Optimization Design according to claim 1, is characterized in that: in described step 7, thunderbolt times N=N in every 100 kilometers of given line corridor _g* (b+4h)/10, wherein b is the spacing of composite material pole tower two lightning conducters, and h is the average height of composite material pole tower lightning conducter.

3. combined type composite material shaft tower lightning protection Optimization Design according to claim 1, is characterized in that: described given CG lightning density value N _dbe 2.78 times/km ²* year.