CN102570444A - Direct current active power filter device for high-voltage direct current transmission - Google Patents

Abstract

The invention provides a direct current active power filter device for high-voltage direct current (HVDC) transmission, and belongs to the technical field of HVDC transmission. The device comprises a passive filter (1), an LC series resonance circuit (2), an active power filter (3) and a coupling transformer (4), wherein the active power filter (3) is connected in series with the passive filter (1) through the coupling transformer (4); and the LC series resonance circuit (2) is connected in parallel with the primary side of the coupling transformer (4). By the device, equipment investment and operation maintenance cost are effectively decreased, electric energy loss produced by unit capacity is reduced, and the economy of the direct current active power filter device for the HVDC transmission is improved.

Description

A kind of direct current active filter that is used for high voltage direct current transmission

Technical field

The invention belongs to the high voltage dc transmission technology field, be specifically related to a kind of direct current active filter that is used for high-voltage dc transmission HVDC (high-voltage direct current).

Background technology

Along with the development of power electronic technology and the raising of digital signal processor performance, active filter progressively is applied to HVDC transmission system filtering in recent years.Than Traditional passive filter PF (Passive Filter); Active Power Filter-APF APF (Active Power Filter) has that volume is little, efficient is high, filtered band is wide, there are characteristics such as off resonance soon and not in dynamic response, is a kind of practical filter.Abroad; DC active power filter APF is in Sweden--Denmark 250kV; Industry operation in Denmark--Norway 350kV and Germany--the Sweden 450kV DC transmission engineering; And obtained satisfied result, the sky of China--extensively DC transmission engineering has also adopted DC active power filter APF first.Because HVDC transmission system can produce a large amount of harmonic waves; And jumbo Active Power Filter-APF APF not only need adopt expensive power electronic element; Increased electric energy loss and heat abstractor burden simultaneously, this will increase equipment investment and operation expense.APF mainly contains following shortcoming: the electric energy loss that unit capacity produces is bigger, and equipment investment and operation expense height, economic benefit are relatively low.

In order to reduce the capacity of active filter, common way is active filter to be connected with No. 12/24 double-tuned filter constitute the mixed filtering device, and active part will not bear 12 times and 24 subharmonic capacity like this.But in actual motion, the low order uncharacteristic harmonics also has bigger capacity, like 6 subharmonic.Though 3 subharmonic can not increase the active filter capacity not within the filtering scope in addition, can produce bigger loss when it flows through coupling transformer, and equipment investment and operation expense height.

Summary of the invention

In order to overcome the deficiency of above-mentioned prior art; The present invention provides a kind of direct current active filter that is used for high-voltage dc transmission HVDC; Effectively reduce its equipment investment and operation expense, reduced the electric energy loss that unit capacity produces, improve the economy of HVDC DC filtering device.

In order to realize the foregoing invention purpose, the present invention takes following technical scheme:

A kind of direct current active filter that is used for high voltage direct current transmission, said device comprises passive filter 1, LC series resonant circuit 2, Active Power Filter-APF 3 and coupling transformer 4; Said Active Power Filter-APF 3 is connected with passive filter 1 through said coupling transformer 4, and said LC series resonant circuit 2 is parallelly connected with the primary side of coupling transformer 4.

Said passive filter 1 adopts No. 12/24 tuned filter; Said tuned filter is a double-tuned filter.

Said double-tuned filter comprises capacitor C ₁, C ₂With reactor L ₁, L ₂Said capacitor C ₂With reactor L ₂Parallel connection back and reactor L ₁With capacitor C ₁Series connection successively.

Said LC series resonant circuit 2 comprises harmonic measure and control protected location, power capacitor C ₃And the reactor L of series connection with it ₃

Said Active Power Filter-APF 3 is a parallel active filter; Said Active Power Filter-APF 3 comprises current transformer, controller, pulse-width modulator, unidirectional AC/DC converter and accessory power supply.

Said coupling transformer 4 is unidirectional transformer.

Compared with prior art, beneficial effect of the present invention is: circuit structure is simple, is easy to safeguard; Equipment investment and cost are lower; The electric energy loss that unit capacity produces is lower; Practical, economy and reliability are high.

Description of drawings

Fig. 1 is the schematic diagram of direct current active filter of the present invention;

Wherein, 1. passive filter, 2.LC series resonant circuit, 3. Active Power Filter-APF, 4. coupling transformer.

Embodiment

Below in conjunction with accompanying drawing the present invention is described further.

Like Fig. 1, a kind of direct current active filter that is used for high voltage direct current transmission, said device comprises passive filter 1, LC series resonant circuit 2, Active Power Filter-APF 3 and coupling transformer 4; Said Active Power Filter-APF 3 is connected with passive filter 1 through said coupling transformer 4, and said LC series resonant circuit 2 is parallelly connected with the primary side of coupling transformer 4.

Said passive filter 1 adopts No. 12/24 tuned filter; Said tuned filter is a double-tuned filter.

Said double-tuned filter comprises capacitor C ₁, C ₂With reactor L ₁, L ₂Said capacitor C ₂With reactor L ₂Parallel connection back and reactor L ₁With capacitor C ₁Series connection successively.

Said LC series resonant circuit 2 comprises harmonic measure and control protected location, power capacitor C ₃And the reactor L of series connection with it ₃

Said Active Power Filter-APF 3 is a parallel active filter; Said Active Power Filter-APF 3 comprises current transformer, controller, pulse-width modulator, unidirectional AC/DC converter and accessory power supply.

Said coupling transformer 4 is unidirectional transformer.

With three--wide DC transmission system rectification side is an example, explains that this direct current active filter capacity can effectively reduce.The each harmonic voltage and current effective value that conventional dc active power filter bears is as shown in table 1.

Table 1

Can calculate conventional dc active power filter capacity S according to table 1 data _F

$S_F=\sqrt{\underset{n=6}{\overset{60}{\mathrm{\Σ}}}{\left|U_F^{\left(n\right)}\right|}^2}\sqrt{\underset{n=6}{\overset{60}{\mathrm{\Σ}}}{\left|U_F^{\left(n\right)}\right|}^2}=167\mathrm{kVA}$

The each harmonic voltage and current effective value that dc active power filter of the present invention bears is as shown in table 2.

Table 2

Can calculate dc active power filter capacity of the present invention

by table 2;

Owing to no longer bear 6 bigger subharmonic of capacity, the capacity of dc active power filter of the present invention is merely about 1/3 of conventional dc active power filter capacity.

What should work as explanation at last is: above embodiment is only in order to technical scheme of the present invention to be described but not to its restriction; Although the present invention has been carried out detailed explanation with reference to the foregoing description; The those of ordinary skill in said field is to be understood that: still can specific embodiments of the invention make amendment or replacement on an equal basis; And do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (8)

1. direct current active filter that is used for high voltage direct current transmission, it is characterized in that: said device comprises passive filter (1), LC series resonant circuit (2), Active Power Filter-APF (3) and coupling transformer (4); Said Active Power Filter-APF (3) is connected with passive filter (1) through said coupling transformer (4), and said LC series resonant circuit (2) is parallelly connected with the primary side of coupling transformer (4).

2. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 1 is characterized in that: said passive filter (1) adopts No. 12/24 tuned filter.

3. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 2, it is characterized in that: said tuned filter is a double-tuned filter.

4. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 3, it is characterized in that: said double-tuned filter comprises capacitor C ₁, C ₂With reactor L ₁, L ₂Said capacitor C ₂With reactor L ₂Parallel connection back and reactor L ₁With capacitor C ₁Series connection successively.

5. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 1 is characterized in that: said LC series resonant circuit (2) comprises harmonic measure and control protected location, power capacitor C ₃And the reactor L of series connection with it ₃

6. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 1 is characterized in that: said Active Power Filter-APF (3) is a parallel active filter.

7. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 6 is characterized in that: said Active Power Filter-APF (3) comprises current transformer, controller, pulse-width modulator, unidirectional AC/DC converter and accessory power supply.

8. a kind of direct current active filter that is used for high voltage direct current transmission according to claim 1 is characterized in that: said coupling transformer (4) is unidirectional transformer.