CN103078283B - The defining method of the online anti-icing electric current of a kind of end multiple line direct supply system in parallel contact line pairing SVG - Google Patents

Abstract

The invention discloses the defining method of the online anti-icing electric current of a kind of end multiple line direct supply system in parallel contact line pairing SVG.The method is by monitoring and recording the environmental information such as humiture, wind speed, and traction substation feeder line side voltage vector and current phasor, adopt the formulae discovery of deriving to obtain the span of anti-icing electric current, can the dynamic change with the change of environmental condition and traction load.The method test is simple, accuracy is high, and the time dependent curve of anti-icing electric current of monitoring gained can be used as the foundation of online anti-icing system design and running.

Description

The defining method of the online anti-icing electric current of a kind of end multiple line direct supply system in parallel contact line pairing SVG

Technical field

The present invention relates to the defining method of the online anti-icing electric current of a kind of end multiple line direct supply system in parallel contact line pairing SVG, relate to the online anti-icing technology of contact line, belong to power supply unit security technology area.

Background technology

China's electric railway total kilometrage increases fast, and some new electric railway circuits probably will pass through the region that icing easily occurs for high and cold, high humidity and high altitude localities etc., and " Harbin-Dalian railway line " will be the high-speed railway that the first bar in the world passes through cold region; High-speed railway and heavy haul railway fast development, improve further to the requirement of power supply reliability, the important section of a lot of heavy icing area simultaneously, and the icing impact serious time with can be used for deicing seldom defines outstanding contradiction; Icing adds contact line hard spot, not only exacerbates bow net electric arc, more easily accelerates the abrasion of pantograph pan, even causes accidents such as scraping bow.Contact line icing disaster problem has become the problem of departments at different levels extensive concern, and in order to eliminate icing, also can ensure necessary electric energy supply of driving a vehicle, the online anti-icing technology of contact line will become one of main method of the anti-ice-melt of following electric railway simultaneously.

Current domestic electric railway mainly adopts artificial deicing, length consuming time, and efficiency is low, poor stability.Short circuit ice-melt scheme under test at present, is placed on supply arm end by reactance or resistance, utilizes its short circuit current to carry out ice-melt, and when determining size of current, directly getting its value is critical anti-icing electric current.This kind determines that the method for electric current does not consider the impact on Traction networks pressure, must affect driving, be only applicable to off-line type ice-melt.Chinese patent (application number: 201110141921.6,201110033636.2,201120033756.8,201120176640.X) propose the online anti-de-icing method of contact line, but the defining method of its electric current not clear and definite; Existing anti-icing electric current all with reference to the anti-icing electric current defining method of off-line type, does not consider the impact of Traction networks pressure.In the electric railway of current China, the up-downgoing multiple line electric power system of end parallel running account for very most of, therefore for the multiple line direct-furnish electric power system contact line of end parallel connection, be badly in need of invention can effectively anti-ice-melt, can ensure that contact line net pressure remains on the anti-icing electric current defining method in allowed band again.

Summary of the invention

For the situation of prior art, the invention provides the defining method of the online anti-icing electric current of a kind of end multiple line direct supply system in parallel contact line pairing SVG, adopt the method, in real time, automatically can regulate anti-icing electric current, ensure anti-icing effect, ensure Traction networks supply power voltage simultaneously, do not affect driving.Thus lay the foundation for the application of the online anti-icing method of contact line.

The present invention solves the problems of the technologies described above adopted technical scheme and comprises the steps:

The first step: by contact wire model material determination wire equivalent diameter D, 20 DEG C of D.C. resistance R ₂₀, the solar absorption coefficient ε of wire, the radiation coefficient ε of wire _cw, the temperature coefficient y of wire _s, environment parameter measuring instrument device is set in observation station and records wind speed V _w, wind direction angle factor K _angle, ambient temperature T _a, consult physical parameter table determination atmospheric density ρ _f, air moves viscosity μ _f, air conduction coefficient k _f, after testing location latitude γ determines, the critical anti-icing electric current I of contact wire can be calculated by following formula _c0:

In formula, T _sfor the target temperature of setting contact wire heating, P _sofor solar radiation density, M is with higher value.

Second step: by the critical anti-icing electric current I of following formula determination contact line _c1:

I _C1＝(1+k)I _C0

In formula, k is carrier cable and the ratio of the current division ratio of contact wire.

3rd step: record locomotive load electric current I _loadand power-factor angle obtain power supply siding-to-siding block length l, locomotive distance traction substation distance l ₁, the anti-icing electric current I of perception ensured needed for the anti-icing effect in all fronts of up and down line can be determined by following formula _c11:

Meanwhile, the anti-icing electric current I of capacitive needed for the anti-icing effect in all fronts of up and down line is ensured _c12value is with in the greater;

4th step: measure to obtain contact line head end voltage U _n, terminal voltage U ₂, record locomotive load electric current I _loadand power-factor angle the unit length impedance Z of single line contact line and the unit length mutual impedance Z of up and down line is calculated according to contact line space layout, contact wire and carrier cable type _{i, II}, obtain power supply siding-to-siding block length l, locomotive distance traction substation distance l ₁, the anti-icing upper current limit I of contact line perception allowed is pressed by following formula determination Traction networks _c21, the anti-icing upper current limit I of capacitive _c22:

In formula, u _minfor the long-time minimum voltage of the contact line allowed within the scope of Traction networks power supply safety, U _maxfor the long-time ceiling voltage of the contact line allowed within the scope of Traction networks power supply safety, Z ' and θ ' _lbe respectively Z+Z _{i, II}modulus value and phase angle, i.e. Z+Z _{i, II}=Z ' ∠ θ ' _l.

5th step: get I _c21and I _c22in the greater be Traction networks pressure allow the anti-icing upper current limit I of contact line _c2.

6th step: judge I _c2character, if inductance current, get I _c1'=I _c11if capacity current, gets I _c1'=I _c12;

7th step: the value of anti-icing electric current is I _c1' and I _c21in smaller.

The principle that the present invention relates to is as follows:

q _S+q _R＝q _c+q _r+q _p(1)

The heat balance equation that formula (1) is contact wire, in formula, q _sfor daylight shortwave radiation heat, q _rfor transmission current Joule heat, q _cfor convection heat losses, q _rfor wire radiation thermal loss, q _pfor the heat that wire temperature rise absorbs.Above-mentioned every expression formula is respectively:

The hot q of daylight shortwave radiation _s

q _s＝ε·P _so·sinδ·D(2)

In formula, ε is sun absorption coefficient; P _sofor solar radiation density; D is wire equivalent diameter; δ is sun drift angle, depends on latitude γ, can be calculated as follows:

δ＝arccos[(113.5°-|γ|)cos(180°-γ)](3)

Transmission current Joule heat q _r

q _R＝I _C0 ²R _T(4)

In formula, I _c0for the electric current that contact wire flows through, R _tfor considering the conductor resistivity of kelvin effect, can be calculated as follows:

R _T＝R ₂₀[1+y _s(T _S-20)](5)

In formula, y _sfor the temperature coefficient of wire; R ₂₀conductor resistance when being 20 DEG C; T _sfor setting the target temperature of wire-heated.

Convection heat losses q _c

$q_{c1}=[1.01+0.0372{\left(\frac{D{\mathrm{\ρ}}_f{V}_w}{{\mathrm{\μ}}_f}\right)}^{0.52}]k_f{K}_{\mathrm{angle}}(T_S-T_a)---\left(6\right)$

$q_{c2}=\left[0.0119{\left(\frac{D{\mathrm{\ρ}}_f{V}_w}{{\mathrm{\μ}}_f}\right)}^{0.6}\right]k_f{K}_{\mathrm{angle}}(T_S-T_a)---\left(7\right)$

Formula (6) be applicable to wind speed lower time, formula (7) be applicable to wind speed higher time, under any circumstance, the result of calculation of the two, gets the greater.In formula, T _afor ambient temperature, T _sfor setting the target temperature of wire-heated; D is wire equivalent diameter; k _ffor air conduction coefficient; K _anglefor wind direction coefficient, can be calculated by following formula:

K _angle＝1.194-cos(β)+0.194cos(2β)+0.368sin(2β)(8)

In formula, β refers to the angle of wind direction and wire vertical direction.

Wire radiation thermal loss q _r

$q_r=0.0178\·D\·{\mathrm{\ϵ}}_{\mathrm{cw}}\·[{\left(\frac{T_S}{100}\right)}^4-{\left(\frac{T_a}{100}\right)}^4]---\left(9\right)$

In formula, T _afor ambient temperature, T _sfor setting the target temperature of wire-heated; D is wire equivalent diameter; ε _cwfor wire radiation rate.

The heat q that wire temperature rise absorbs _p

$q_p=\mathrm{cm}\frac{d{T}_S}{\mathrm{d\τ}}---\left(10\right)$

In formula, m is the quality of conductor, and m=ρ _cv _c, ρ _cfor the density of conductor material, v _cfor the volume of unit length wire, c is the thermal capacitance of conductor material.

Formula (2)-(10) are substituted into formula (1), then formula (1) can be expanded into:

In formula, M is with higher value.

When conductor temperature is stablized, the steady state solution of above formula is:

Formula (12) is the critical anti-icing electric current I of contact wire _c0expression formula.

The electric current of contact wire and carrier cable distributes schematic diagram as shown in Figure 1.Contact wire flows through electric current I ₁, carrier cable flows through electric current I ₂, the electric current on two wires distributes by the leakage impedance of two wires, and the ratio of its electric current is:

$k=\frac{I_2}{I_1}=\frac{Z_1-Z_{12}}{Z_2-Z_{12}}---\left(13\right)$

In formula, Z ₁, Z ₂, Z ₁₂be respectively the mutual impedance of contact wire impedance, carrier cable impedance, contact wire and carrier cable.

Contact wire flows through critical anti-icing electric current I _c0time, the electric current on carrier cable is kI _c0, so the critical anti-icing electric current I of single line contact line _c1for (1+k) I _c0.

The online anti-icing system schematic diagram of direct-furnish electric power system contact line as shown in Figure 2.At the head end of supply arm and end, stillness wattless occurrence apparatus (SVG) is installed respectively, capacitive character and inductive feature can be shown as based on SVG operating state, the SVG controlling first and last end sends respectively or absorbs idle, utilize electric current through line resistance heating, ensure that contact wire temperature is more than or equal to 0 DEG C, realize anti-ice-melt function; Maintain line voltage distribution to stablize simultaneously, ensure safe train operation.

Multiple line up-downgoing end parallel operation, circuit can be reduced to Fig. 3.In Fig. 3, Z, Z _{i, II}the unit length impedance of single line contact line and the unit length mutual impedance of up and down line respectively, l is power supply siding-to-siding block length, l ₁for locomotive is to traction substation distance, l ₂for locomotive is to the distance of supply arm end, with be respectively three sections of electric currents on up and down line, for the operating current of end SVG, for locomotive load electric current, with for the electric current on mesh A, B, C.

Voltage, current equation are write out to A, B, C mesh of circuit shown in Fig. 3:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_A={\stackrel{\·}{I}}_{\mathrm{load}}\\ {\stackrel{\·}{I}}_B={\stackrel{\·}{I}}_2\\ Z\·l_1\·({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_C)+Z_{I,\mathrm{II}}\·l_1\·{\stackrel{\·}{I}}_C+Z\·l_2\·({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)+Z_{I,\mathrm{II}}\·l_2\·{\stackrel{\·}{I}}_C-Z\·l_2\·{\stackrel{\·}{I}}_C\\ -Z_{I,\mathrm{II}}\·l_2\·({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)-Z\·l_1\·{\stackrel{\·}{I}}_C-Z_{I,\mathrm{II}}\·l_1\·({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_C)=0\end{array}\right.---\left(14\right)$

Try to achieve the electric current on mesh C

${\stackrel{\·}{I}}_C=\frac{1}{2}{\stackrel{\·}{I}}_2+\frac{l_2}{2l}{\stackrel{\·}{I}}_{\mathrm{load}}---\left(15\right)$

Three sections of electric currents then on up and down line are respectively:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{I,1}=\frac{1}{2}{\stackrel{\·}{I}}_2+(1-\frac{l_1}{2l}){\stackrel{\·}{I}}_{\mathrm{load}}\\ {\stackrel{\·}{I}}_{I,2}=-\frac{1}{2}{\stackrel{\·}{I}}_2+\frac{l_1}{2l}{\stackrel{\·}{I}}_{\mathrm{load}}\\ {\stackrel{\·}{I}}_{\mathrm{II}}=\frac{1}{2}{\stackrel{\·}{I}}_2+\frac{l_1}{2l}{\stackrel{\·}{I}}_{\mathrm{load}}\end{array}\right.---\left(16\right)$

In order to ensure ice-melt effect, on circuit, any place On The Current Value is all greater than the critical anti-icing electric current I of single line contact line _c1, by the operating current under end SVG perception, capacitive state be designated as respectively with

When end SVG is operated in perceptual state, formula (16) becomes:

Analysis mode (17) first formula, arranges as end SVG operating current I _c11equation, obtain its separate:

If critical anti-icing electric current I _c1with load current I _loadmeet formula (18) first formula, illustrate that the shunting of now load current can meet anti-icing, do not need additionally to drop into anti-icing electric current; If load current can not meet, for ensureing the operating current I of anti-icing end SVG completely _c11with critical anti-icing electric current I _c1, load current I _loadand phase angle relation see formula (18) second formula.

Analysis mode (17) second and third formula, arranges as I _c11equation, obtain its separate:

To direct-furnish multiple line electric power system, when up-downgoing end is in parallel, for ensureing the perceptual operating current I of anti-icing end SVG completely _c11with critical anti-icing electric current I _c1, load current I _loadand phase angle relational expression such as formula shown in (18), (19), two formulas will meet simultaneously.Analyze two formulas above, the perceptual operating current I of end SVG _c11jointly determined by multiple factor, thus by upper two formulas arrangements be:

End SVG when perceptual state, I _c11in its span, its expression formula all the time:

Can show that end SVG is when perceptual state by formula (21), ensure the anti-icing electric current that should drop into completely.

End SVG is when capacitive state, and formula (16) becomes:

Formula (22) is solved, obtains I _c12in its span, its expression formula all the time:

In formula, I _c12value is with in the greater.

Can show that end SVG is when capacitive state by formula (23), ensure the anti-icing electric current that should drop into completely.

Equivalent electric circuit according to Fig. 3, meets formula (24) at any time.

${\stackrel{\·}{U}}_S=(Z+Z_{I,\mathrm{II}})\·(\frac{1}{2}l\·{\stackrel{\·}{I}}_2+\frac{1}{2}{l}_1\·{\stackrel{\·}{I}}_{\mathrm{load}})+{\stackrel{\·}{U}}_2---\left(24\right)$

In formula, supply arm head end voltage is supply voltage for supply arm terminal voltage, by the operating current under end SVG perception, capacitive state be expressed as with its value is by the critical anti-icing electric current I of single line contact line _c1determine together with multiple factors such as supply conductor voltage requirement, the phase of its phase angle and terminal voltage 90 ° or-90 °, then supply arm terminal voltage is (wherein "+" is operated in perceptual state corresponding to end SVG, and "-" respective ends SVG is operated in capacitive state).

When SVG2 is operated in perceptual state, formula (24) is converted into:

In formula, Z ' and θ ' _lbe respectively Z+Z _{i, II}modulus value and phase angle, i.e. Z+Z _{i, II}=Z ' ∠ θ ' _l, by the decision such as structure, line style of contact line, for locomotive electric current I _loadphase angle.

Solve formula (25), obtain:

In formula,

By formula (26), (27) comprehensively, the anti-icing upper current limit I of multiple line direct-furnish contact line perception of the end parallel connection that Traction networks pressure allows can be obtained _c21:

In formula, u _minfor the long-time minimum voltage of the contact line allowed within the scope of Traction networks power supply safety.

When SVG2 is operated in capacitive state, formula (24) is converted into:

Solve formula (29), obtain:

By formula (27), (30) comprehensively, the anti-icing upper current limit I of multiple line direct-furnish contact line capacitive of the end parallel connection that Traction networks pressure allows can be obtained _c22:

In formula, U _maxfor the long-time ceiling voltage of the contact line allowed within the scope of Traction networks power supply safety.

Formula (28) is comprehensive with formula (31), gets its greater, is the anti-icing upper current limit I of multiple line direct-furnish contact line of the end parallel connection that Traction networks pressure allows _c2, now SVG2 drop into galvanic properties and electric current the greater be consistent.

I _c2the anti-icing electric current determining input is perception or capacitive, so get I _c11and I _c12in with I _c2the electric current that character is consistent is I _c1'.Ensure the electric current I that multiple line circuit is anti-icing completely _c1' press the anti-icing upper current limit I of the contact line allowed with Traction networks _c2relatively, if the former is less, the anti-icing electric current I of contact line is got _c=I _c1'; If the former is comparatively large, then sacrifice anti-icing effect in short-term, preferential guarantee Traction networks net pressure, gets the anti-icing electric current I of contact line _c=I _c2.

By monitoring and recording the environmental information such as humiture, wind speed, traction substation feeder line side voltage vector and current phasor, adopt the formulae discovery of deriving can obtain the span of anti-icing electric current.Idiographic flow is shown in Fig. 4.

Accompanying drawing explanation

Fig. 1 is that the electric current of contact wire and carrier cable distributes schematic diagram.

Fig. 2 is the online anti-icing system schematic diagram of direct-furnish supply power mode.

Fig. 3 is the online anti-icing system equivalent circuit diagram of the multiple line direct-furnish supply power mode of end parallel connection.

Fig. 4 is the determination flow chart of the online anti-icing electric current of the multiple line direct supply system of end parallel connection.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in further detail.

Embodiment

Ambient temperature is T _a=-3 DEG C, wind speed V _w=3m/s, humidity 85%, wind vertically blows to wire and wind direction angle factor K _angle=1, to CTMH-120 type contact wire, wait radius surface 6.45mm, specific heat capacity 386J/ (kg.K), 20 DEG C of D.C. resistance 0.2315 Ω/km, solar absorption coefficient 1, radiation coefficient 0.7.Calculate according to formula (12), obtaining it, to close on anti-icing electric current be I _c0=191A.

Measure contact wire self-impedance, carrier cable self-impedance, mutual impedance between contact wire and carrier cable are respectively Z ₁=0.236+j0.837 Ω/km, Z ₂=0.285+j0.838 Ω/km, Z ₁₂=0.049+j0.487 Ω/km, is calculated the current division ratio k=0.934 of carrier cable and contact wire by formula (13), then the critical anti-icing electric current of single line contact line is I _c1=(1+k) I _c0=370A.

Power supply siding-to-siding block length is l=20km, single line contact line equiva lent impedance Z=0.132+j0.383 Ω/km, the mutual impedance Z of up and down line _{i, II}=0.0274+j0.121 Ω/km, locomotive is positioned at interval middle l ₁=10km, locomotive electric current I _loadvalue 400A, power factor can be calculated respectively by formula (21) and formula (22) and ensure the anti-icing required inductance current I dropped into completely _c11=652A, capacity current I _c12=659A.

Calculate under end SVG is operated in perception, capacitive state by formula (27), (30), the contact line inductance current upper limit I that Traction networks pressure allows _c21=1544A, capacity current upper limit I _c22=483A, the then anti-icing upper current limit I of contact line of Traction networks pressure permission _c2for 1544A.

I _c2for perception, then get I _c1'=I _c11=652A, ensure that anti-icing required anti-icing electric current is 652A completely, press the anti-icing upper current limit 1544A of the contact line allowed to compare with Traction networks, the former is less, so the anti-icing electric current I of contact line _cvalue be 652A.Otherwise, if the former is comparatively large, then sacrifice ice-melt effect in short-term, preferential guarantee Traction networks net pressure.

The anti-icing electric current of contact line gets I _ctime, calculate known, contact wire temperature rises from ambient temperature-3 DEG C of indexes, within about 6 minutes, namely reaches 0 DEG C and stablizes.During this period, on Traction networks, voltage is as shown in table 1 everywhere.

Table 1 up and down line supply conductor voltage everywhere

Ceiling voltage on Traction networks is 27.5kV, minimum voltage is 23.5966kV.

So after determining anti-icing electric current according to the method, contact wire temperature reaches 0 DEG C after within about 6 minutes, being and keeps stable, and supply conductor voltage is in the allowed band of [19kV, 29kV].While effectively anti-icing, ensure contact line net pressure, do not affect driving.

Claims (1)

1. a defining method for the online anti-icing electric current of end multiple line direct supply system in parallel contact line pairing SVG, is characterized in that carrying out according to following flow process:

The first step: by contact wire model material determination wire equivalent diameter D, 20 DEG C of D.C. resistance R ₂₀, the solar absorption coefficient ε of wire, the radiation coefficient ε of wire _cw, the temperature coefficient y of wire _s, environment parameter measuring instrument device is set in observation station and records wind speed V _w, wind direction angle factor K _angle, ambient temperature T _a, consult physical parameter table determination atmospheric density ρ _f, air moves viscosity μ _f, air conduction coefficient k _f, after testing location latitude γ determines, the critical anti-icing electric current I of contact wire can be calculated by following formula _c0:

In formula, T _sfor the target temperature of setting contact wire heating, P _sofor solar radiation density, M is with higher value;

Second step: by the critical anti-icing electric current I of following formula determination contact line _c1:

I _C1＝(1+k)I _C0

In formula, k is carrier cable and the ratio of the current division ratio of contact wire;

3rd step: record locomotive load electric current I _loadand power-factor angle obtain power supply siding-to-siding block length l, locomotive distance traction substation distance l ₁, the anti-icing electric current I of perception ensured needed for the anti-icing effect in all fronts of up and down line can be determined by following formula _c11:

Meanwhile, the anti-icing electric current I of capacitive needed for the anti-icing effect in all fronts of up and down line is ensured _c12value is with in the greater;

4th step: measure to obtain contact line head end voltage U _n, terminal voltage U ₂, record locomotive load electric current I _loadand power-factor angle the unit length impedance Z of single line contact line and the unit length mutual impedance Z of up and down line is calculated according to contact line space layout, contact wire and carrier cable type _{i, II}, obtain power supply siding-to-siding block length l, locomotive distance traction substation distance l ₁, the anti-icing upper current limit I of contact line perception allowed is pressed by following formula determination Traction networks _c21, the anti-icing upper current limit I of capacitive _c22:

In formula, u _minfor the long-time minimum voltage of the contact line allowed within the scope of Traction networks power supply safety, U _maxfor the long-time ceiling voltage of the contact line allowed within the scope of Traction networks power supply safety, Z ' and θ _l' be respectively Z+Z _{i, II}modulus value and phase angle, i.e. Z+Z _{i, II}=Z ' ∠ θ _l';

5th step: get I _c21and I _c22in the greater be Traction networks pressure allow the anti-icing upper current limit I of contact line _c2;

6th step: judge I _c2character, if inductance current, get I _c1'=I _c11if capacity current, gets I _c1'=I _c12;

7th step: the value of anti-icing electric current is I _c1' and I _c21in smaller.