CN103956739A - Method for achieving electric power filtering and reactive compensation of direct-current transmission converter station - Google Patents

Abstract

The invention provides a method for achieving electric power filtering and reactive compensation of a direct-current transmission converter station. The direct-current transmission converter station comprises a thyristor current converter, a filter and two converter transformers. Each converter transformer comprises three windings which are a grid side winding, an extending edge winding and a common winding respectively. The grid side winding of each converter transformer is connected into an alternating cutter power grid in a star connection mode. The extending edge winding and the public winding of each converter transformer are connected with the thyristor current converter in an extending edge triangular connection mode. The common windings of the two converter transformers are connected in parallel and then are connected with the filter. The method for achieving the electric power filtering and the reactive compensation of the direct-current transmission converter station can eliminate the adverse effect of harmonic waves and reactive power on the converter transformers in the direct current transmission, solve the problems of the restriction of system impedance on electric power filtering efficiency and the series-parallel connection resonance between the filter and the system impedance, ensure the efficient, safe and stable operation of the high-voltage direct-current transmission system converter station and improve the power quality of the power grid.

Description

The electric filtering at a kind of direct-current transmission converter station and the implementation method of reactive power compensation

Technical field

The present invention relates to supplying electricity and power distribution field, be specifically related to the electric filtering at a kind of direct-current transmission converter station and the implementation method of reactive power compensation.

Background technology

HVDC (High Voltage Direct Current) transmission system is widely used in the fields such as long-distance and large-capacity power transmission, region power networking and new-energy grid-connected.At present, high voltage direct current transmission is mainly taking 12 pulse wave systems as elementary cell, the main mode of connection of its current conversion station is as follows: converter transformer comprises net side winding (winding) and two windings of valve side winding (secondary winding), net side winding incoming transport electrical network, valve side winding connects thyristor converter device; The net side winding of two converter transformers adopts Y-connection, wherein the valve side winding of a converter transformer adopts Y-connection, the valve side winding of an other converter transformer adopts triangle to connect, thereby meets the needed commutation voltage of 12 pulse wave thyristor converter device; On filter access converter transformer net side ac bus, be used for the harmonic wave that the non-linear thyristor converter device of filtering produces, and first-harmonic is carried out to reactive power compensation.But the mode of connection of present high voltage DC power transmission converter station and filtering merit compensating method imperfection: first, the net side of harmonic wave and the idle converter transformer of all flowing through and valve side winding, in the iron core of converter transformer and structural member, pass through stronger harmonic flux, transformer insulated difficulty is strengthened, loss and heating increase, it is large that vibration and noise become, thereby affect operational efficiency and the stability thereof of system.Secondly, for avoiding and system impedance generation series parallel resonance, passive filter usually carries out the humorous design of offset, thereby affects the filter effect of filter.

Being not difficult to find out, also there is certain defect in prior art.

Summary of the invention

Technical problem to be solved by this invention is to provide the electric filtering at a kind of direct-current transmission converter station and the implementation method of reactive power compensation, can eliminate humorously in direct current transportation to involve the idle harmful effect to converter transformer; The problems such as the series parallel resonance between restriction and filter and the system impedance of resolution system impedance to electric filtering usefulness; Ensure the stable operation of HVDC Converters highly effective and safe, improve the quality of power supply of electrical network.

For achieving the above object, the invention provides following technical scheme:

The electric filtering at direct-current transmission converter station and an implementation method for reactive power compensation, described direct-current transmission converter station comprises thyristor converter device, filter and two converter transformers; Each converter transformer is every comprises three windings mutually, is respectively net side winding, prolongs limit winding and common winding; The net side winding of each converter transformer adopts Y-connection mode incoming transport electrical network; The limit winding that prolongs of each converter transformer all adopts extend-triangle connected mode to be connected with thyristor converter device with common winding; After the common winding parallel connection of two converter transformers, connect filter.

Further, the common winding of described converter transformer is the converter transformer of zero equivalent impedance design.

Further, described filter is complete modulation feature time filter.

Further, described filter carries out reactive power compensation in filtering harmonic wave.

Further, the turn ratio of prolonging limit winding and common winding of described converter transformer is .

Further, the winding of converter transformer according to prolong limit winding near iron core, net side winding from iron core farthest, the arrangement of common winding in the middle of being positioned at arrange, and the structure and layout of winding are adjustable, are zero for realizing the equivalent impedance of common winding.

Further, described filter is single tuned filter, double-tuned filter or three-tuned filter.

More specifically technique effect of the present invention is:

(1), converter transformer has special impedance design, filter designs for complete modulation.The equivalent impedance of the common winding of converter transformer is designed to zero, and in common winding, connects novel complete modulation feature time filter, and this has just formed the zero impedance short-circuited conducting sleeve to harmonics electric current, thereby reaches good harmonic suppression effect.And be subject to the constraint of converter transformer net side winding impedance, complete modulation filter not can with AC system impedance generation series parallel resonance, this can fundamentally break away from the restriction of system impedance to Filtering Efficacy.

(2), converter transformer has special structure, its valve side winding employing extend-triangle wiring.Adopt the mode at valve side winding access filtering power factor compensator, the compensation nearby of reactive power and the inhibition nearby of harmonic wave are realized, idle and the harmonic wave being produced by thyristor converter device can not crosstalked to the net side winding side of converter transformer, and AC network side.

(3), due to harmonic wave and idle all just having obtained suppressing nearby and compensating when the converter side, this has not only reduced supplementary load loss, temperature rise, the noise and vibration of converter transformer, and has realized High Power Factor and the high-efficiency stable operation of whole current conversion station system.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

The electric filtering at a kind of direct-current transmission converter station that Fig. 1 provides for the embodiment of the present invention and the topology diagram of the implementation method of reactive power compensation;

Fig. 2 is the detailed winding diagram of Fig. 1 embodiment.

Fig. 3 is the equivalent circuit diagram of Fig. 1 embodiment.

Description of reference numerals:

1, AC network; 2, the first converter transformer;

3, the second converter transformer; 4, filter;

5, thyristor converter device; 6, the net side winding of the first converter transformer;

7, the net side winding of the second converter transformer; 8, filter;

9, the first converter transformer prolong limit winding; 10, the second converter transformer prolong limit winding;

11, the common winding of the first converter transformer; 12, the common winding of the second converter transformer;

13: AC system equivalent circuit;

14: the equivalent circuit of converter transformer and filter;

15, the equivalent circuit of thyristor converter device.

Embodiment

For making object, technical scheme and the advantage of the embodiment of the present invention clearer, below in conjunction with the embodiment of the present invention and accompanying drawing, the technical scheme in the embodiment of the present invention is clearly and completely described.It should be noted that, described embodiment is only the present invention's part embodiment, instead of whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

Below in conjunction with brief description of the drawings the specific embodiment of the present invention.

Embodiment

Refer to Fig. 1 and Fig. 2, for the electric filtering at a kind of direct-current transmission converter station and the implementation method of reactive power compensation, direct-current transmission converter station comprises two converter transformers (the first converter transformer 2 and the second converter transformer 3), a filter 4 and a thyristor converter device 5; Described converter transformer is every all comprises three windings mutually, is respectively net side winding, prolongs limit winding and common winding; Prolong the valve side winding that limit winding and common winding form converter transformer.Wherein, net side winding adopts Y-connection mode incoming transport electrical network 1; Prolonging limit winding and common winding all adopts extend-triangle wiring to carry out connecing thyristor converter device 5 after phase shift; After common winding 12 parallel connections of the common winding 11 of the first converter transformer and the second converter transformer, connect filter 4.

It should be noted that, in the present embodiment, the structure of two converter transformers is the same.

The common winding of described converter transformer is the converter transformer of zero equivalent impedance design.The winding of converter transformer according to prolong limit winding near iron core, net side winding from iron core farthest, the arrangement of common winding in the middle of being positioned at arrange, and the structure and layout of winding are adjustable, the equivalent impedance of realizing common winding by adjusting the structure and layout of winding is zero.

The turn ratio of prolonging limit winding and common winding of described converter transformer is ; The common winding 11 of prolonging limit winding 9 and the first converter transformer of the first converter transformer makes valve side line voltage phase shift+15 ° after adopting extend-triangle wiring, the common winding 12 of prolonging limit winding 10 and the second converter transformer of the second converter transformer adopts line voltage phase shift-15 ° that make valve side after extend-triangle wiring, thereby ensure that two valve winding in converter transformer line voltages have the phase shift of 30 degree, thereby meet 12 pulse wave thyristor converter device 5 needed commutation voltages.

The voltage vector correspondent equal of two converter transformer common winding, connects filter 4 after the common winding parallel connection of two converter transformers; When described filter filtering harmonic wave, first-harmonic is carried out to reactive power compensation, realized in the valve side of converter transformer and carried out harmonic wave and idle inhibition nearby and compensation.

Described filter 4 is complete modulation feature time filter.Referring to Fig. 2, is the detailed winding diagram of Fig. 1 embodiment, after the parallel connection of two converter transformer common winding, accesses filter 8.Filter 8 carries out complete modulation design to harmonics (11,13,23,25 etc.), can adopt single tuned filter, double-tuned filter, three-tuned filter etc.

Refer to Fig. 3, below filtering merit under complex chart 3 mode of connection coming in key-drawing 1,2 to describe mend principle:

By multi winding transformer theory, can obtain following equation:

$\left\{\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{Ag}1-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{a1-c1-h}={\stackrel{\·}{I}}_{\mathrm{Ag}1-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{A1-a1-h}{Z}_{3h}\\ {\stackrel{\·}{U}}_{\mathrm{Bg}1-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{b1-a1-h}={\stackrel{\·}{I}}_{\mathrm{Bg}1-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{B1-b1-h}{Z}_{3h}\\ {\stackrel{\·}{U}}_{\mathrm{Cg}1-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{c1-b1-h}={\stackrel{\·}{I}}_{\mathrm{Cg}1-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{C1-c1-h}{Z}_{3h}\\ {\stackrel{\·}{U}}_{\mathrm{Ag}2-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{b2-a2-h}={\stackrel{\·}{I}}_{\mathrm{Ag}2-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{a2-A2-h}{Z}_{3h}\\ {\stackrel{\·}{U}}_{\mathrm{Bg}2-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{c2-b2-h}={\stackrel{\·}{I}}_{\mathrm{Bg}2-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{b2-B2-h}{Z}_{3h}\\ {\stackrel{\·}{U}}_{\mathrm{Cg}2-h}-\frac{N_1}{N_3}{\stackrel{\·}{U}}_{a2-c2-h}={\stackrel{\·}{I}}_{\mathrm{Cg}2-h}{Z}_{h13}-\frac{N_1{N}_2}{N_3^2}{\stackrel{\·}{I}}_{c2-C2-h}{Z}_{3h}\end{array}\right.---\left(1\right)$

In formula, h is harmonic number; N ₁, N ₂, N ₃be respectively net side winding, prolong the number of turn of limit winding and common winding; Z _h12for the short-circuit impedance between net side winding and Yan Bian winding; Z _h13for the short-circuit impedance between net side winding and common winding; Z _h23for prolonging the short-circuit impedance between limit winding and common winding.Z _h3for the equivalent impedance of common winding, its value is designed to zero.That is:

$Z_{h3}=\frac{(Z_{h13}/N_1^2+Z_{h23}/N_2^2-Z_{h12}-N_1^2)N_3^2}{2}=0---\left(2\right)$

Ignore exciting current, can obtain the magnetic potential balance equation of converter transformer:

$\left\{\begin{array}{c}{N}_1{\stackrel{\·}{I}}_{\mathrm{Ag}1-h}+N_2{\stackrel{\·}{I}}_{A1-a1-h}+N_3{\stackrel{\·}{I}}_{a1-c1-h}=0\\ N_1{\stackrel{\·}{I}}_{\mathrm{Bg}1-h}+N_2{\stackrel{\·}{I}}_{B1-b1-h}+N_3{\stackrel{\·}{I}}_{b1-a1-h}=0\\ N_1{\stackrel{\·}{I}}_{\mathrm{Cg}1-h}+N_2{\stackrel{\·}{I}}_{C1-c1-h}+N_3{\stackrel{\·}{I}}_{c1-b1-h}=0\\ N_1{\stackrel{\·}{I}}_{\mathrm{Ag}2-h}+N_2{\stackrel{\·}{I}}_{a2-A2-h}+N_3{\stackrel{\·}{I}}_{b2-a2-h}=0\\ N_1{\stackrel{\·}{I}}_{\mathrm{Bg}2-h}+N_2{\stackrel{\·}{I}}_{b2-B2-h}+N_3{\stackrel{\·}{I}}_{c2-b2-h}=0\\ N_1{\stackrel{\·}{I}}_{\mathrm{Cg}2-h}+N_2{\stackrel{\·}{I}}_{c2-C2-h}+N_3{\stackrel{\·}{I}}_{a2-c2-h}=0\end{array}\right.---\left(3\right)$

Can obtain following equation by Kirchhoff's current law (KCL):

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1-a1-h}={\stackrel{\·}{I}}_{A1L-h}\\ {\stackrel{\·}{I}}_{B1-b1-h}={\stackrel{\·}{I}}_{B1L-h}\\ {\stackrel{\·}{I}}_{C1-c1-h}={\stackrel{\·}{I}}_{C1L-h}\\ {\stackrel{\·}{I}}_{a1-x-h}={\stackrel{\·}{I}}_{A1-a1-h}+{\stackrel{\·}{I}}_{b1-a1-h}-{\stackrel{\·}{I}}_{a1-c1-h}\\ {\stackrel{\·}{I}}_{b1-y-h}={\stackrel{\·}{I}}_{B1-b1-h}+{\stackrel{\·}{I}}_{c1-b1-h}-{\stackrel{\·}{I}}_{b1-a1-h}\\ {\stackrel{\·}{I}}_{c1-z-h}={\stackrel{\·}{I}}_{C1-c1-h}+{\stackrel{\·}{I}}_{a1-c1-h}-{\stackrel{\·}{I}}_{c1-b1-h}\\ {\stackrel{\·}{I}}_{a1-c1-h}+{\stackrel{\·}{I}}_{c1-b1-h}+{\stackrel{\·}{I}}_{b1-a1-h}=0\\ {\stackrel{\·}{I}}_{a2-A2-h}=-{\stackrel{\·}{I}}_{A2L-h}\\ {\stackrel{\·}{I}}_{b2-B2-h}=-{\stackrel{\·}{I}}_{B2L-h}\\ {\stackrel{\·}{I}}_{c2-C2-h}=-{\stackrel{\·}{I}}_{C2L-h}\\ {\stackrel{\·}{I}}_{a2-z-h}={\stackrel{\·}{I}}_{b2-a2-h}-{\stackrel{\·}{I}}_{a2-A2-h}-{\stackrel{\·}{I}}_{a2-c2-h}\\ {\stackrel{\·}{I}}_{b2-x-h}={\stackrel{\·}{I}}_{c2-b2-h}-{\stackrel{\·}{I}}_{b2-B2-h}-{\stackrel{\·}{I}}_{b2-a2-h}\\ {\stackrel{\·}{I}}_{c2-y-h}={\stackrel{\·}{I}}_{a2-c2-h}-{\stackrel{\·}{I}}_{c2-C2-h}-{\stackrel{\·}{I}}_{c2-b2-h}\\ {\stackrel{\·}{I}}_{a2-c2-h}+{\stackrel{\·}{I}}_{c2-b2-h}+{\stackrel{\·}{I}}_{a2-c2-h}=0\end{array}\right.---\left(4\right)$

Can obtain following equation by Kirchhoff's second law:

$\left\{\begin{array}{c}{\stackrel{\·}{U}}_{a1-c1-h}={\stackrel{\·}{U}}_{b2-a2-h}={\stackrel{\·}{U}}_{x-o-h}-{\stackrel{\·}{U}}_{z-o-h}\\ {\stackrel{\·}{U}}_{c1-b1-h}={\stackrel{\·}{U}}_{a2-c2-h}={\stackrel{\·}{U}}_{z-o-h}-{\stackrel{\·}{U}}_{y-o-h}\\ {\stackrel{\·}{U}}_{b1-a1-h}={\stackrel{\·}{U}}_{c2-b2-h}={\stackrel{\·}{U}}_{y-o-h}-{\stackrel{\·}{U}}_{x-o-h}\\ {\stackrel{\·}{U}}_{x-o-h}=({\stackrel{\·}{I}}_{a1-x-h}+{\stackrel{\·}{I}}_{b2-x-h})Z_{\mathrm{fh}}\\ {\stackrel{\·}{U}}_{y-o-h}=({\stackrel{\·}{I}}_{b1-y-h}+{\stackrel{\·}{I}}_{c2-y-h})Z_{\mathrm{fh}}\\ {\stackrel{\·}{U}}_{z-o-h}=({\stackrel{\·}{I}}_{c1-z-h}+{\stackrel{\·}{I}}_{a2-z-h})Z_{\mathrm{fh}}\end{array}\right.---\left(5\right)$

In formula, Z _fhfor the impedance of filter.

It is as follows that combinatorial formula (1)-(5) can obtain the current expression of net side winding of converter transformer:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{Ag}1-h}={\stackrel{\·}{I}}_{\mathrm{Ag}2-h}=\frac{N_1{N}_3({\stackrel{\·}{I}}_{C1L-h}-{\stackrel{\·}{I}}_{B2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\\ -\frac{N_1({3N}_2+N_3)({\stackrel{\·}{I}}_{A1L-h}-{\stackrel{\·}{I}}_{A2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\\ {\stackrel{\·}{I}}_{\mathrm{Bg}1-h}={\stackrel{\·}{I}}_{\mathrm{Bg}2-h}=\frac{N_1{N}_3({\stackrel{\·}{I}}_{A1L-h}-{\stackrel{\·}{I}}_{C2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\\ -\frac{N_1({3N}_2+N_3)({\stackrel{\·}{I}}_{B1L-h}-{\stackrel{\·}{I}}_{B2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\\ {\stackrel{\·}{I}}_{\mathrm{Cg}1-h}={\stackrel{\·}{I}}_{\mathrm{Cg}2-h}=\frac{N_1{N}_3({\stackrel{\·}{I}}_{B1L-h}-{\stackrel{\·}{I}}_{A2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\\ -\frac{N_1(3N_2+N_3)({\stackrel{\·}{I}}_{C1L-h}-{\stackrel{\·}{I}}_{C2L-h})Z_{\mathrm{fh}}}{N_3^2{Z}_{h13}+6N_1^2{Z}_{\mathrm{fh}}}\end{array}\right.---\left(6\right)$

Again because filter is complete modulation filter to harmonics, so have for harmonics:

Z _fh＝0 (7)

In conjunction with (6), (7) equation, can draw for harmonics equation and set up:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{Ag}1-h}={\stackrel{\·}{I}}_{\mathrm{Ag}2-h}=0\\ {\stackrel{\·}{I}}_{\mathrm{Bg}1-h}={\stackrel{\·}{I}}_{\mathrm{Bg}2-h}=0\\ {\stackrel{\·}{I}}_{\mathrm{Cg}1-h}={\stackrel{\·}{I}}_{\mathrm{Cg}2-h}=0\end{array}\right.---\left(8\right)$

That is to say, drop into after filter, eliminated the harmonic current of the net side winding of converter transformer, the harmful effect of harmonic reduction to converter transformer.In addition, the impedance of high order harmonics becomes capacitive for first-harmonic, when complete modulation filter filtering harmonic wave, first-harmonic has been carried out to reactive power compensation.

The electric filtering at a kind of direct-current transmission converter provided by the invention station and the implementation method of reactive power compensation, can eliminate and humorously in direct current transportation involve the idle harmful effect to converter transformer; The problems such as the series parallel resonance between restriction and filter and the system impedance of resolution system impedance to electric filtering usefulness; Ensure the stable operation of HVDC Converters highly effective and safe, improve the quality of power supply of electrical network.

More specifically technique effect of the present invention is:

(1), converter transformer has special impedance design, filter designs for complete modulation.The equivalent impedance of the common winding of converter transformer is designed to zero, and in common winding, connects novel complete modulation feature time filter, and this has just formed the zero impedance short-circuited conducting sleeve to harmonics electric current, thereby reaches good harmonic suppression effect.And be subject to the constraint of converter transformer net side winding impedance, complete modulation filter not can with AC system impedance generation series parallel resonance, this can fundamentally break away from the restriction of system impedance to Filtering Efficacy.

(2), converter transformer has special structure, its valve side winding employing extend-triangle wiring.Adopt the mode at valve side winding access filtering power factor compensator, realize the compensation nearby of reactive power and the inhibition nearby of harmonic wave, the idle and harmonic wave being produced by thyristor converter device 5 can not crosstalked to net side winding side and the AC network side of converter transformer.

(3), due to harmonic wave with idlely all just obtaining suppressing nearby and compensating near converter side, this has not only reduced supplementary load loss, temperature rise, the noise and vibration of converter transformer, and has realized High Power Factor and the high-efficiency stable operation of whole current conversion station system.

The above embodiment has only expressed one embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with claims.

Claims (7)

1. the electric filtering at direct-current transmission converter station and an implementation method for reactive power compensation, described direct-current transmission converter station comprises thyristor converter device, filter and two converter transformers; Each converter transformer is every comprises three windings mutually, is respectively net side winding, prolongs limit winding and common winding; It is characterized in that:

The net side winding of each converter transformer adopts Y-connection mode incoming transport electrical network;

The limit winding that prolongs of each converter transformer all adopts extend-triangle connected mode to be connected with thyristor converter device with common winding;

After the common winding parallel connection of two converter transformers, connect filter.

2. the electric filtering at direct-current transmission converter according to claim 1 station and the implementation method of reactive power compensation, is characterized in that:

The common winding of described converter transformer is the converter transformer of zero equivalent impedance design.

3. the electric filtering at direct-current transmission converter according to claim 1 station and the implementation method of reactive power compensation, is characterized in that:

Described filter is complete modulation feature time filter.

4. the electric filtering at direct-current transmission converter according to claim 3 station and the implementation method of reactive power compensation, is characterized in that:

Described filter carries out reactive power compensation in filtering harmonic wave.

5. the electric filtering at direct-current transmission converter according to claim 1 station and the implementation method of reactive power compensation, is characterized in that:

The turn ratio of prolonging limit winding and common winding of described converter transformer is

6. the electric filtering at direct-current transmission converter according to claim 2 station and the implementation method of reactive power compensation, is characterized in that:

The winding of converter transformer according to prolong limit winding near iron core, net side winding from iron core farthest, the arrangement of common winding in the middle of being positioned at arrange, and the structure and layout of winding are adjustable, are zero for realizing the equivalent impedance of common winding.

7. the electric filtering at direct-current transmission converter according to claim 3 station and the implementation method of reactive power compensation, is characterized in that:

Described filter is single tuned filter, double-tuned filter or three-tuned filter.