CN101807783A - High-voltage high-power biharmonic electrical deicing method for overhead power transmission line - Google Patents

Abstract

The invention provides a high-voltage high-power biharmonic electrical deicing method for an overhead power transmission line. In the method, a high-voltage high-power power electronic variable frequency resonance device outputs two high-frequency voltages with two different frequencies to ensure that two high-frequency currents with two different frequencies can be generated in a resonance capacitor which is connected in series with a transmission line and an LC resonance circuit which is connected in parallel with the transmission line so as to heat an iced transmission line. The two high-frequency currents with two different frequencies are introduced into the iced transmission line, so that the skin effect of the transmission line can be greatly improved, corresponding line equivalent resistance is increased, the ice-melting current of the line is reduced under the condition that the same ice-melting power is generated, and damage of line overcurrent is reduced. The method has the advantages of furthest utilizing capacity of the high-voltage high-power power electronic variable frequency resonance device, along with high ice-melting efficiency and high deicing speed, is applicable to ice-melting of single-phase and three-phase transmission lines, has high actionability and wide application prospect, and can generate enormous economic and social benefits.

Description

High-voltage high-power biharmonic electrical deicing method for overhead power transmission line

Technical field

The present invention relates to a kind of high-voltage high-power biharmonic electrical deicing method for overhead power transmission line.Belong to the power system security field.

Background technology

China is one of the most serious country of powerline ice-covering in the world.Serious icing can cause the rapid decline of transmission line machinery and electric property, thereby causes the generation of icing accident.In existing deicing technological means, the artificial de-icing method efficient of machinery is low, the risk factor height, and the cycle is long, is difficult to large tracts of land and promotes; Adopting the method for new material lead to increase cost often can not excellent popularization, particularly in old circuit; The direct current ice-melting method is two circuit ice-melts simultaneously often, at the common required ice-melt duration of three-phase coated by ice of overhead power transmission line situation, and complicated operation.Circuit great current deicing method requires the integrality of circuit, and very high idle output is arranged, and ice-melt efficient is low; A kind of single tuning frequency conversion resonance vibration short circuit ice-melt that proposes in the recent period only can be pure resistive resonant tank in single resonance point generation and improve the lead heating efficiency, further improve the lead heating efficiency and fail to use the exportable high-frequency harmonic amount of high-voltage and high-power power electronic converter plant, go to utilize the kelvin effect of transmission line and the rated capacity of device to export the meritorious circuit heating ice-melt that makes to greatest extent.

Summary of the invention

Technical problem: the present invention is intended to overcome the deficiency of existing de-icing technology, maximally utilises the kelvin effect of transmission line and the installed capacity of high-power frequency conversion resonance vibration ice-melt power supply, and efficient electric heating transmission line melts icing automatically fast.

Technical scheme: the present invention forms by series capacitor, lc circuit in parallel to transmission line can double-tuned equivalent electric circuit, ice-melting phase high-power frequency conversion resonance vibration ice-melt power supply produces double frequency point resonance by regulating output, form two and be pure resistive efficient electric heating loop, lead is efficiently generated heat, melt icing automatically fast.High-voltage high-power biharmonic electrical deicing method for overhead power transmission line of the present invention is: be in parallel by second inductor and second capacitor and form a resonant circuit, series connection first resonant capacitor and described resonant circuit between high voltage high power resonant vibration frequency conversion device and overhead transmission line then, formation can double-tuned line electricity deicing heating circuit; The high voltage high power resonant vibration frequency conversion device comprises the high frequency voltage of two different frequencies by output, make the high-frequency resonant electric current that produces two different frequencies on can double-tuned electric deicing heating circuit, form two and be pure resistive resonance electricity deicing heating circuit, electric heating line realizes melting fast icing, has utilized the high voltage high power resonant vibration frequency conversion installed capacity simultaneously to greatest extent.

The high-frequency resonant electric current of described two different frequencies, one of them frequency are about 1k, and another is its 5 subharmonic.

Described first resonant capacitor, inductor and second capacitor satisfy and have double-tuned characteristic after line inductance value L1 is connected, and satisfy the requirement of the high-frequency resonant electric current of described two different frequencies.

Beneficial effect:

(1) high ice-melt efficient, the maximization of ice-melt supply unit capacity utilance;

(2) applied widely, different electric pressures, single-phase, three-phase line can use, flexible operation, adaptability is strong;

(3) can make portable device, be adapted at each area operation.

Description of drawings

Fig. 1: the single-phase double tunning deicing of overhead transmission line principle schematic,

Fig. 2: the double-tuned circuit schematic diagram,

Fig. 3: the double tunning deicing when frequency f equivalence be pure resistive circuit heating circuit,

Fig. 4: the double tunning deicing is at pure resistive circuit heating circuit of being of frequency f ' time equivalence,

Fig. 5: the single-phase double tunning deicing of overhead transmission line wiring schematic diagram,

Fig. 6: overhead transmission line three-phase double tunning deicing wiring schematic diagram,

Have among the figure: transmission line high frequency equivalent resistance R, transmission line equivalent inductance L1, the first resonant capacitor C1, the second capacitor C2, high-frequency coupling inductance L 2, line ice-melting power supply E.

Embodiment

High-voltage high-power biharmonic electrical deicing method for overhead power transmission line is based on the electrical deicing method of kelvin effect and double-tuned circuit two point resonance principle, the kelvin effect that produces when being intended to maximally utilise transmission line circulation high-frequency current and the installed capacity of high-power frequency conversion resonance vibration ice-melt power supply, efficient electric heating transmission line realizes melting fast automatically icing.Specifically can by the shorting stub short circuit, promptly be considered as a threephase load to the three-phase conducting wire of circuit one end to the whole three-phase circuit under power-off condition, three-phase short circuit point is as the neutral point of load.And add high-power frequency conversion resonance vibration ice-melt power supply at the other end of circuit, and series resonance capacitor and LC antiresonant circuit between this power electronics converter plant and circuit, formation can double-tuned electric heating loop.The ice-melt power supply makes the ice-melt loop at two resonance points resonance take place all by output high frequency fundametal compoment and injection harmonic component, form two circuit heating circuits that are pure resistive, thereby device output fundametal compoment and inject harmonic component and can both produce real component and make the circuit ice-melt of efficiently generating heat, install idle output simultaneously and reduce to zero in theory, ice-melt supply unit capacity has obtained utilizing more fully.Again since on the lead high frequency fundamental current and harmonic current all can produce kelvin effect, the equivalent resistance of circuit can increase greatly, the heating of circuit also can major part concentrates on the near surface of circuit, ice-melt speed further improves.

Be in parallel by the second inductor L2 and the second capacitor C2 and form a resonant circuit, then at line ice-melting power supply E and overhead transmission line 1 series connection, first resonant capacitor C1 and described resonant circuit, formation can double-tuned line electricity deicing heating circuit; Line ice-melting power supply E comprises the high frequency voltage of two different frequencies by output, make the high-frequency resonant electric current that produces two different frequencies on can double-tuned electric deicing heating circuit, form two and be pure resistive resonance electricity deicing heating circuit, electric heating line realizes melting fast icing, has utilized line ice-melting power supply E capacity simultaneously to greatest extent.The high-frequency resonant electric current of described two different frequencies, one of them frequency be (as 0.9Hz, 1Hz, 1.1Hz etc.) about 1kHz, and another is its 5 subharmonic.

The described first resonant capacitor C1, high-frequency coupling inductance L 2 and the second capacitor C2 satisfy and have double-tuned characteristic after transmission line equivalent inductance L1 connects, and satisfy the requirement of the high-frequency resonant electric current of described two different frequencies.

The capacitor of double-tuned circuit adopts metallized noninductive film capacitor string to form.The capacitor elementary cell is specified alternating voltage 3000V, and specified alternating current 100A's is single, forms the capacitor heap by such capacitor series/parallel.Inductance adopts high frequency amorphous mutual reactor.

Described serial connection is actual with capacitor to be the resonant capacitor heap.Its basic composition is the noninductive big current film capacitor of 100A/3000V, improves the withstand voltage and current carrying capacity of electric capacity by their series/parallel, constitutes the actual resonant capacitor heap under the high-voltage great-current ruuning situation.Described tandem electric inductance is actual to be high frequency amorphous mutual reactor, guarantees its normal operation under high-frequency current.

As shown in Figure 1: in case the circuit icing, promptly have a power failure and in icing power transmission line 1, seal in capacitor and pile 2, with the parallel resonance lc circuit, after adding ice-melt power supply 5 formation deicing loops again, resonant capacitor heap 2, parallel resonance lc circuit and transmission line 1 equivalent inductance L1 form and can double-tuned ice-melt heat equivalent electric circuit, as shown in Figure 2.

Double tunning equivalent electric circuit specificity analysis:

The series LC circuit impedance

Lc circuit impedance in parallel

Whole double-tuned circuit impedance

$Z\left(f\right)=\mathrm{Zs}\left(f\right)+\mathrm{Zp}\left(f\right)=j(2\mathrm{\πf}{L}_1-\frac{1}{2\mathrm{\π}{\mathrm{fC}}_1})+{(j2\mathrm{\πf}{C}_2+\frac{1}{j2\mathrm{\π}{\mathrm{fL}}_2})}^{-1}$

Make Z (f)=0, and abbreviation gets

(2πf) ⁴L ₁L ₂C ₁C ₂-(2πf) ²(L ₁C ₁+L ₂C ₂+L ₂C ₁)+1＝0

Find the solution two roots that obtain equation:

$f=\frac{1}{2\mathrm{\π}}\sqrt{\frac{L_1{C}_1+L_2{C}_2+L_2{C}_1-\sqrt{{(L_1{C}_1+L_2{C}_2+L_2{C}_1)}^2-4L_1{L}_2{C}_1{C}_2}}{2L_1{L}_2{C}_1{C}_2}}$

$f^{\′}=\frac{1}{2\mathrm{\π}}\sqrt{\frac{L_1{C}_1+L_2{C}_2+L_2{C}_1-\sqrt{{(L_1{C}_1+L_2{C}_2+L_2{C}_1)}^2-4L_1{L}_2{C}_1{C}_2}}{2L_1{L}_2{C}_1{C}_2}}$

By above-mentioned analysis as can be known double-tuned circuit at frequency f and f ' down resonance can take place all, promptly equiva lent impedance is 0.Working as high-power frequency conversion resonance vibration deicing power supply output frequency like this is the high frequency fundametal compoment of f and the injection harmonic component that frequency is f ', the electric deicing heating circuit of equivalence comprises two as shown in Figure 3 and is pure resistive line electricity heating circuit, thereby the high efficiency electric heating line rapidly and efficiently melts icing.

In conjunction with concrete performance, can be divided into following two kinds of embodiments:

Scheme one: uniline deicing.As shown in Figure 4, deicing power supply neutral end ground connection and with the circuit other end also ground connection simultaneously, resonant capacitance and lc circuit in parallel seal in the middle of the uniline, make deicing power supply, icing circuit, the earth constitute the loop like this.The deicing power supply is by double resonance algorithm controls output when powering on deicing, make can double-tuned deicing heating circuit operation equivalent electric circuit as shown in Figure 3, high efficiency electric heating transmission line melts icing fast.This operational mode is particularly suitable for the ground wire of transmission line or the contact line deicing of electric railway.

Scheme two: three-phase line deicing simultaneously.The consideration circuit is a three phase symmetry load, one end of three phase line connects by shorting stub, each seals in resonant capacitor and lc circuit in parallel in mutually the lead other end, and then access high voltage high power resonant vibration frequency conversion deicing power supply, the neutral ground of deicing power supply, form three-phase deicing loop, as shown in Figure 5.Three-phase is realized deicing simultaneously like this, saves the ice-melt time, improves ice-melt efficient.

Claims (3)

1. high-voltage high-power biharmonic electrical deicing method for overhead power transmission line, it is characterized in that: be in parallel by second inductor (L2) and second capacitor (C2) and form a resonant circuit, series connection first resonant capacitor (C1) and described resonant circuit between line ice-melting power supply (E) and overhead transmission line (1) then, formation can double-tuned line electricity deicing heating circuit; Line ice-melting power supply (E) comprises the high frequency voltage of two different frequencies by output, make the high-frequency resonant electric current that produces two different frequencies on can double-tuned electric deicing heating circuit, form two and be pure resistive resonance electricity deicing heating circuit, electric heating line realizes melting fast icing, has utilized line ice-melting power supply (E) capacity simultaneously to greatest extent.

2. high-voltage high-power biharmonic electrical deicing method for overhead power transmission line according to claim 1 is characterized in that: the high-frequency resonant electric current of described two different frequencies, one of them frequency are about 1k, and another is its 5 subharmonic.

3. high-voltage high-power biharmonic electrical deicing method for overhead power transmission line according to claim 1, it is characterized in that described first resonant capacitor (C1), high-frequency coupling inductance (L2) and second capacitor (C2) satisfy and have double-tuned characteristic after transmission line equivalent inductance (L1) is connected, and satisfy the requirement of the high-frequency resonant electric current of described two different frequencies.

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