CN103199476A - Method and application for acquiring direct current load value of direct current deicing device of convertor station ground wires - Google Patents

Abstract

The invention discloses a method and application for acquiring a direct current load value of a direct current deicing device of convertor station ground wires, relates to electrified wire netting electric transmission line direct current deicing technology, and provides a reasonable acquiring method and application of equivalent resistance of ground wires. The reasonable acquiring method and application of equivalent resistance of the ground wires overcome the defects that in a convertor station ground wire direct current design, calculation of the equivalent resistance of the ground wires is complicated, and the equivalent resistance of the ground wires is not easy to obtain due to the fact that the ground wires are repeatedly connected in parallel and a conducting wire is adopted to act as a bonding conductor and a bus wire. The method for acquiring the direct current load value of the direct current load value of the direct current deicing device of the convertor station ground wires is characterized in that by utilizing an average concept, an average resistance of a unit conducting wire and the ground wires is obtained, and then direct current resistance load of the direct current deicing device is calculated according to a direct current deicing connecting wire of the convertor station ground wires. Due to the fact that influences of conducting wire resistance on ground wire resistance under repeatedly parallel connection conditions are fully considered, excellent accuracy and easy operability are possessed, output direct current voltage and current and capacity of direct current deicing can be accurately estimated, and certain convenience is brought for designing the direct current deicing device of the convertor station ground wires.

Description

Current conversion station ground wire DC de-icing device DC load value-acquiring method, application

Technical field

The present invention relates to grid power transmission circuit DC ice melting technology, especially relates to a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method, application.

Background technology

The threat of ice damage is the big technical barrier that the electric power system industrial quarters does one's utmost to tackle always.In recent years, along with the global climate condition changes, low temperature sleet freezing weather frequently occurs in China south, Central China, North China, repeatedly causes China each province transmission line large tracts of land, the long-time stoppage in transit, brings about great losses for national economy and people's lives.In order to prevent the appearance again of this situation, behind the ice damages in 2008, China electric power scientific worker has independently carried out the research and development of DC ice melting technology and device, successfully developed the high power DC deicing device with complete independent intellectual property right, mainly comprise the band special rectifier transformer, be not with multiple patterns such as special rectifier transformer and vehicle-mounted removable, and then apply in the whole nation.Ice age in-2011 in 2009, the 19 cover DC de-icing devices of only having installed in the south electric network have all been brought into play significant role, the above circuit of 110kV is carried out DC ice melting amount to 234 times, wherein surplus the 500kV alternating current circuit 40 time, given full play to the power of DC de-icing device.

DC de-icing device not only can carry out ice-melt to aerial condutor at present, also can carry out ice-melt to ground wire, ground wire is carried out the conventional method of ice-melt for after ground wire being carried out all insulation transformation, adopt lead as bonding conductor and bus bar, ground wire is carried out repeatedly in parallel, reducing the ground wire equivalent resistance, and then reduce the deicing device VD, transform difficulty to reduce the ground wire insulation, reduce the purpose of investment for trnasforming urban land.Then, the recycling lead as bonding conductor with the ground line parallel, because aerial condutor is as bus bar, its electric current that passes through is bigger, have certain low pressure drop on it, at number of times in parallel more after a little while, this voltage drop numerical value is less, its output voltage influence to DC de-icing device can be ignored, but when the situation of number of times in parallel more (mainly be over against than long transmission line), along with the increase of number of times in parallel, the electric current in the lead can be increasing, voltage drop meeting is very big on it at this moment, therefore, when estimation DC de-icing device DC load, can not ignore conductor resistance again, need calculate it with regard to the good engineering method, could select the current conversion station ground wire DC de-icing device that mates most for use according to accurate DC load value then.

Summary of the invention

The objective of the invention is to: the problem at prior art exists provides a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method, application.

Goal of the invention of the present invention is achieved through the following technical solutions:

A kind of current conversion station ground wire DC de-icing device DC load value-acquiring method is characterized in that this method may further comprise the steps:

(1) average resistance that calculates unit length direct current transportation lead and unit length direct current transportation ground wire is R and r;

(2) according to current conversion station ground wire DC ice melting lead, the ground wire mode of connection, derive the recurrence formula that calculates DC de-icing device dc load value, and according to this formula computational load resistance value.

Preferably, the unit length described in the step (1) is 1 kilometer.

Preferably, for current conversion station ground wire DC ice melting lead, the ground wire mode of connection is the isometric n time in parallel ground wire DC ice melting wiring circuit topology of ground wire, its DC load value computing formula is

X wherein _nRepresented by following recurrence formula:

$\left\{\begin{array}{c}{X}_n=(X_{n-1}+\frac{2R}{n})//\frac{r}{2n}\\ X_1=\frac{r}{2n}\end{array}\right.;n=\mathrm{1,2,3}.....,$ Utilize this formula, bring transmission line length l into, and frequency n in parallel, can calculate DC de-icing device DC load value.

A kind of application of current conversion station ground wire DC de-icing device DC load value, it is characterized in that, determine current conversion station ground wire DC de-icing device output voltage, electric current and capability value according to the DC load value that calculates, thereby design the current conversion station ground wire DC de-icing device that mates most.

Preferably, described voltage, electric current computational methods are: according to

$\left\{\begin{array}{c}{I}_n=I_{n-1}+\frac{I_{n-1}(X_{n-1}+2R/n)}{X_1};n=\mathrm{1,2,3}....\\ I_1=2I\end{array}\right.;U_n=I_n{R}_n,$ X wherein _nRepresented by following recurrence formula:

$\left\{\begin{array}{c}{X}_n=(X_{n-1}+\frac{2R}{n})//\frac{r}{2n}\\ X_1=\frac{r}{2n}\end{array}\right.;n=\mathrm{1,2,3}.....,$ R is unit length direct current transportation lead average resistance, and r is the average resistance of unit length direct current transportation ground wire, and I is single ground wire deicing current value.

Preferably, single ground wire deicing current value I should be greater than any one section minimum ice melting current of ground wire.

Compared with prior art, the present invention has the following advantages:

1, engineering method and the computing formula of utilizing the present invention to propose, can be under the arbitrarily inferior situation in parallel of current conversion station ground wire, ground wire DC de-icing device direct current load is estimated, this method has taken into full account repeatedly the situation lower wire resistance in parallel influence of line resistance over the ground simultaneously, possesses accuracy and easy operating preferably.

2, utilize the inventive method to obtain the DC de-icing device load after, can estimate output dc voltage, electric current and the capacity of DC ice melting comparatively accurately, for the design of current conversion station ground wire DC de-icing device provides certain convenience.

Description of drawings

Fig. 1 is the isometric n time in parallel ground wire DC ice melting wiring circuit topology figure of ground wire.

Embodiment

The present invention is described in detail below in conjunction with the drawings and specific embodiments.

Embodiment

A kind of under any inferior situation of current conversion station ice-melt ground line parallel, can easyly obtain the engineering method of DC de-icing device DC load, this method is at first by calculating every kilometer average resistance of direct current transportation lead and circuit, then, the equivalent electric circuit topology that is connected with lead according to ground wire, obtain one group of recurrence formula, can estimate the DC de-icing device equivalent resistance by this formula, and then can estimate DC de-icing device output dc voltage and electric current, reach the purpose of simplifying the DC de-icing device design.

The technical solution used in the present invention is such: a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method, comprise step: 1) at first utilize computational methods or engineering survey method to obtain current conversion station DC ice-melting lead and ground line resistance, then respectively divided by lead and ground line length, obtain the average resistance of every kilometer lead and ground wire, suppose to be respectively R and r; 2) according to ground wire DC ice melting wiring circuit topology, as shown in Figure 1.

Consideration is under the situation of general value n at equidistant number of times in parallel, in conjunction with its connected mode, can obtain considering that the DC load computing formula of conductor resistance is:

$R_n=(X_n+\frac{R}{n})l;n=\mathrm{1,2,3}...(3-1)$

X wherein _nRepresented by following recurrence formula:

$\left\{\begin{array}{c}{X}_n=(X_{n-1}+\frac{2R}{n})//\frac{r}{2n}\\ X_1=\frac{r}{2n}\end{array}\right.;n=\mathrm{1,2,3}.....(3-2)$

Utilize this formula, bring transmission line length l into, and frequency n in parallel, can calculate the DC de-icing device DC load of considering conductor resistance.

3) the DC de-icing device Equivalent DC load value that calculates according to following formula, if selecting single ground wire deicing electric current is I (this value should greater than any one section minimum ice melting current of ground wire), then can be according to formula (3-1), (3-2) acquisition DC de-icing device output DC ice melting current, voltage are respectively:

$\left\{\begin{array}{c}{I}_n=I_{n-1}+\frac{I_{n-1}(X_{n-1}+2R/n)}{X_1};n=\mathrm{1,2,3}....\\ I_1=2I\end{array}\right.---(4-1)$

U _n＝I _nR _n （4－2）

Utilize this expression formula to estimate to obtain the DC de-icing device amount of capacity, for the design of current conversion station ground wire DC de-icing device provides certain convenience.

The above only is preferred embodiment of the present invention, not in order to limit the present invention, should be pointed out that all any modifications of doing within the spirit and principles in the present invention, is equal to replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. current conversion station ground wire DC de-icing device DC load value-acquiring method is characterized in that this method may further comprise the steps:

(1) average resistance that calculates unit length direct current transportation lead and unit length direct current transportation ground wire is R and r;

(2) according to current conversion station ground wire DC ice melting lead, the ground wire mode of connection, derive the recurrence formula that calculates DC de-icing device dc load value, and according to this formula computational load resistance value.

2. a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method according to claim 1 is characterized in that the unit length described in the step (1) is 1 kilometer.

3. a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method according to claim 1, it is characterized in that, for current conversion station ground wire DC ice melting lead, the ground wire mode of connection is the isometric n time in parallel ground wire DC ice melting wiring circuit topology of ground wire, its DC load value computing formula is

X wherein _nRepresented by following recurrence formula:

$\left\{\begin{array}{c}{X}_n=(X_{n-1}+\frac{2R}{n})//\frac{r}{2n}\\ X_1=\frac{r}{2n}\end{array}\right.;n=\mathrm{1,2,3}.....,$ Utilize this formula, bring transmission line length l into, and frequency n in parallel, can calculate DC de-icing device DC load value.

4. the application of a current conversion station ground wire DC de-icing device DC load value, it is characterized in that, determine current conversion station ground wire DC de-icing device output voltage, electric current and capability value according to the DC load value that calculates, thereby design the current conversion station ground wire DC de-icing device that mates most.

5. a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method according to claim 4 is characterized in that described voltage, electric current computational methods are: according to

$\left\{\begin{array}{c}{I}_n=I_{n-1}+\frac{I_{n-1}(X_{n-1}+2R/n)}{X_1};n=\mathrm{1,2,3}....\\ I_1=2I\end{array}\right.;U_n=I_n{R}_n,$ X wherein _nRepresented by following recurrence formula:

$\left\{\begin{array}{c}{X}_n=(X_{n-1}+\frac{2R}{n})//\frac{r}{2n}\\ X_1=\frac{r}{2n}\end{array}\right.;n=\mathrm{1,2,3}.....,$ R is unit length direct current transportation lead average resistance, and r is the average resistance of unit length direct current transportation ground wire, and I is single ground wire deicing current value.

6. a kind of current conversion station ground wire DC de-icing device DC load value-acquiring method according to claim 5 is characterized in that single ground wire deicing current value I should be greater than any one section minimum ice melting current of ground wire.

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