CN105678070A - Computing method for direct current transmission line telephone harmonic waveform factor limiting value - Google Patents

Abstract

The invention discloses a computing method for a direct current transmission line telephone harmonic waveform factor limiting value. The method comprises the following steps that A, the inductive coupling interference allowable value e, namely cacophony electromotive force of a direct current transmission line for a telecommunication line is obtained; B, the unit length coupling factor p between a power line and a telegraph loop, the running voltage U, power line structure factor gr, power line and telecommunication line approach section uncompensated 1's, the electric sensitive factor lambdae, access section line loop length 1s, line loop length 1 and power line comprehensive electrostatic screening factor Ke are obtained; C, according to the parameters in the step A and the step B, the telephone harmonic waveform factor limiting value, namely THHFU allowable value of the corresponding cacophony electromotive force on the direct current transmission line is calculated. The direct current harmonic wave horizontal limit value can be calculated under the influences of a high-voltage direct-current power transmission system on a communication system, and the important economic effects and engineering social effects are achieved.

Description

The computational methods of DC power transmission line phone harmonic wave forms coefficient restriction

Technical field

The present invention relates to the computational methods of phone harmonic wave forms coefficient restriction, be specifically related to the computational methods of a kind of DC power transmission line phone harmonic wave forms coefficient restriction.

Background technology

Environmental effect is produced a series of new problem by the raising of D.C. high voltage transmission electric pressure. Along with economic and science and technology development, China has basically formed the communication network with optical fiber for backbone network, based on digital communication in the later stage nineties. High voltage DC power transmission converter station can produce substantial amounts of harmonic voltage under normal operation, produces harmonic voltage and harmonic current on DC line, and its frequency is in audiorange. Harmonic voltage by inductive coupled by capacitive coupling, harmonic current, can be produced cacophony electromotive force on contiguous telecommunication line, make the voice frequency telephone loop in telecommunication line produce noise, reduce communication quality. If cacophony electromotive force exceedes permissible value, then cannot be carried out normal talking, namely claim interference effect. Therefore the close examination HVDC transmission system impact on communication system again, calculates direct current harmonics level limit value, has important economic benefits and engineering social effect.

At present, the permission limits value of DC power transmission line when can calculate the inductive coupled interference effect of DC Transmission Lines On Telecommunication Lines accurately but without relevant algorithm.

Summary of the invention

For solving the deficiency that prior art exists, the invention discloses the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction, the method can in varied situations DC Transmission Lines On Telecommunication Lines inductive coupled interference effect time, calculate the restriction of DC power transmission line phone harmonic wave forms coefficient according to cacophony electromotive force.

For achieving the above object, the concrete scheme of the present invention is as follows:

The computational methods of DC power transmission line phone harmonic wave forms coefficient restriction, comprise the following steps:

A. the inductive coupled limit of interference e of DC Transmission Lines On Telecommunication Lines, i.e. cacophony electromotive force are obtained;

B. the structural coefficient g of the unit length coefficient of coup p between power circuit and telegraph loop, working voltage U, power circuit is obtained_r, power circuit and telecommunication line Approach phase non-compensating length l '_s, electrically susceptible sense coefficient lambda_e, Approach phase line loop length l_s, the comprehensive electrostatic screen COEFFICIENT K of line loop length l, power circuit_e;

C. the phone harmonic wave forms coefficient restriction of corresponding cacophony electromotive force on DC power transmission line, i.e. THHF is calculated according to the parameter in step A and step B_UPermissible value.

Further, described cacophony electromotive force

Wherein, e_lFor cacophony electromotive force that is due to two-wire telephone return wire, power circuit position is asymmetric and that produce; e₂For the cacophony electromotive force produced due to the position unbalanced to ground of two-wire telephone return wire.

e_lExpression formula be:

e₁=16U_eqg_rpl′_sK_e

Wherein, g_rStructural coefficient for power circuit; P is the unit length coefficient of coup between power circuit and telegraph loop, calculates as the case may be and chooses; L '_sFor power circuit and the non-compensating length of telecommunication line Approach phase, choose as the case may be; K_eFor the electrostatic screen coefficient that power circuit is comprehensive.

e₂Expression formula be:

$e_2=U_{eq}{\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3$

Wherein, λ_eFor electricity sensitivity coefficient; P is the unit length coefficient of coup between power circuit and telegraph loop; l_sLine loop length for Approach phase; L is line loop length.

Further, THHF_UThe computing formula of permissible value is:

${\mathrm{THHF}}_U=\frac{\sqrt{3}e}{U\sqrt{{\left(16g_r{\mathrm{pl}}_s^{\′}{K}_e\right)}^2+{({\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3)}^2}}---\left(1\right)$

Further, step B comprises the following steps for the acquisition of the unit length coefficient of coup p between power circuit and telegraph loop:

B1. obtain close to the geometric mean distance δ between equivalent distance a, power transmission wire average height b over the ground, Telecommunication Lines wire average height c over the ground, each wire of power transmission line;

B2. the unit length coefficient of coup p between computing electric line and telegraph loop.

Further, the computing formula of the unit length coefficient of coup p between power circuit and telegraph loop is:

$p=-\frac{5.6\mathrm{\δ}bc}{a^3}---\left(2\right).$

Further, in step 2, unit length coefficient of coup p can be obtained by formula (2); Working voltage U is the nominal voltage of DC power transmission line; The structural coefficient g of power circuit_r, 1/4.5 is generally taken for HVDC transmission line; Power circuit and telecommunication line Approach phase non-compensating length l '_sObtained by reality measurement; Electrically susceptible sense coefficient lambda_eCan be obtained by measuring, 0.8 is generally taken for HVDC transmission line; , Approach phase line loop length l_sDetermine by actual track with line loop length l; The electrostatic screen COEFFICIENT K that power circuit is comprehensive_eThen can determine according to line levels, power line conductive linear diameter and discharge inception voltage and actual motion voltage, determine generally by the form tabled look-up.

Beneficial effects of the present invention:

The present invention in the HVDC transmission system impact on communication system, can directly calculate direct current harmonics level limit value, determines without by concrete actual test, saves manpower and materials, have important economic benefits and engineering social effect.

Accompanying drawing explanation

Fig. 1 is the flow chart of the computational methods of DC power transmission line phone harmonic wave forms coefficient provided by the present invention restriction.

Detailed description of the invention:

Below in conjunction with accompanying drawing, the present invention is described in detail:

As it is shown in figure 1, the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction, comprise the following steps:

A. the inductive coupled limit of interference e of DC Transmission Lines On Telecommunication Lines, i.e. cacophony electromotive force are obtained;

B. the structural coefficient g of the unit length coefficient of coup p between power circuit and telegraph loop, working voltage U, power circuit is obtained_r, power circuit and telecommunication line Approach phase non-compensating length l '_s, electrically susceptible sense coefficient lambda_e, Approach phase line loop length l_s, the comprehensive electrostatic screen COEFFICIENT K of line loop length l, power circuit_e;

C. the phone harmonic wave forms coefficient restriction of corresponding cacophony electromotive force on DC power transmission line, i.e. THHF is calculated according to the parameter in step A and step B_UPermissible value.

1 principle

This method is from the definition expression formula of phone harmonic wave forms coefficient and equivalent disturbing voltage. The definition of equivalent disturbing voltage is:

$U_{eq}=\frac{1}{p_{800}}\sqrt{\mathrm{\Σ}{\left(h_f{p}_f{U}_f\right)}^2}---\left(3\right)$

Wherein, p₈₀₀Weight coefficient during for frequency 800Hz, p₈₀₀=1000; p_fFor the CCITT noise weight coefficient under frequency f; h_fFor the coefficient of coup between power transmission sequence and communication loop, the desirable h of approximate calculation_f=f/800; U_fFor causing the voltage of the interference component under frequency f.

The definition of phone harmonic wave forms coefficient is:

${\mathrm{THFF}}_U=\sqrt{\underset{h=1}{\overset{M}{\Σ}}{(\frac{50h}{8000}\·\frac{p_h}{1000}\·\frac{U_h}{U_1})}^2}\×100\%---\left(4\right)$

Wherein, U_hThe respectively root-mean-square value of h subharmonic current and voltage; U₁The respectively root-mean-square value of fundamental current and voltage; M is the most higher hamonic wave number of times paid close attention to; p_hNoise weighting coefficient for h subharmonic voltage.

When calculating line loop interference effect, often use the equivalent disturbing voltage of unbalance voltage and phase voltage. Can be obtained by formula (4):

THFF_U·U₁=U_eq(5)

Equivalent disturbing voltage is:

$U_{eq}={\mathrm{THFF}}_U\·\frac{U}{\sqrt{3}}---\left(6\right)$

Expression formula in conjunction with cacophony electromotive force is:

$e=\sqrt{e_1^2+e_2^2}---\left(7\right)$

Wherein, e_lFor cacophony electromotive force that is due to two-wire telephone return wire, power circuit position is asymmetric and that produce; e₂For the cacophony electromotive force produced due to the position unbalanced to ground of two-wire telephone return wire.

e_lExpression formula be:

e₁=16U_eqg_rpl′_sK_e(8)

Wherein, g_rStructural coefficient for power circuit; P is the unit length coefficient of coup between power circuit and telegraph loop, calculates as the case may be and chooses; L '_sFor power circuit and the non-compensating length of telecommunication line Approach phase, choose as the case may be; K_eFor the electrostatic screen coefficient that power circuit is comprehensive.

e₂Expression formula be:

$e_2=U_{eq}{\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3---\left(9\right)$

Wherein, λ_eFor electricity sensitivity coefficient; P is the unit length coefficient of coup between power circuit and telegraph loop; l_sLine loop length for Approach phase; L is line loop length.

Formula (6) is arranged:

${\mathrm{THFF}}_U=\frac{\sqrt{3}{U}_{eq}}{U}$

Further abbreviation can derive phone harmonic wave forms coefficient T HFF_U, for:

${\mathrm{THHF}}_U=\frac{\sqrt{3}e}{U\sqrt{{\left(16g_r{\mathrm{pl}}_s^{\′}{K}_e\right)}^2+{({\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3)}^2}}---\left(10\right)$

In order to better illustrate the computational methods of the present invention, it is described in detail below in conjunction with concrete instance:

Assuming exchange overhead transmission line and ground level arrangement, working voltage is 660kV, and wire is average height 25m over the ground, split conductor Shu Zhongzi diameter of wire 0.02m. Communication line is an eight pin crossarm two-wire telephone loop, and wire is copper conductor, and diameter is 3mm, over the ground average height 7m, wire spacing 0.2m, and telephone line total length is 1km, distance power circuit 1km. λ_eValue is 0.8, structural coefficient g_rValue is 1/4.5. Utilize formula (8)-formula (10) that the THHF of corresponding each cacophony electromotive force can be calculated_ULimit value, it is as shown in the table.

The THHF of the corresponding each cacophony electromotive force of table_ULimit value

Cacophony electromotive force limit value (mv)	10	4.5	1
				THFFU(%)	2.9551	1.33	0.30

The specific embodiment of the present invention is described in conjunction with accompanying drawing although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme, those skilled in the art need not pay various amendments or deformation that creative work can make still within protection scope of the present invention.

Claims (8)

1. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction, is characterized in that, comprise the following steps:

A. the inductive coupled limit of interference e of DC Transmission Lines On Telecommunication Lines, i.e. cacophony electromotive force are obtained;

B. the structural coefficient g of the unit length coefficient of coup p between power circuit and telegraph loop, working voltage U, power circuit is obtained_r, power circuit and telecommunication line Approach phase non-compensating length l '_s, electrically susceptible sense coefficient lambda_e, Approach phase line loop length l_s, the comprehensive electrostatic screen COEFFICIENT K of line loop length l, power circuit_e;

C. the phone harmonic wave forms coefficient restriction of corresponding cacophony electromotive force on DC power transmission line, i.e. THHF is calculated according to the parameter in step A and step B_UPermissible value.

2. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 1, is characterized in that, described cacophony electromotive force

Wherein, e_lFor cacophony electromotive force that is due to two-wire telephone return wire, power circuit position is asymmetric and that produce; e₂For the cacophony electromotive force produced due to the position unbalanced to ground of two-wire telephone return wire.

3. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 2, is characterized in that, e_lExpression formula be:

e₁=16U_eqg_rpl′_sK_e

Wherein, g_rStructural coefficient for power circuit; P is the unit length coefficient of coup between power circuit and telegraph loop, calculates as the case may be and chooses; L '_sFor power circuit and the non-compensating length of telecommunication line Approach phase, choose as the case may be; K_eFor the electrostatic screen coefficient that power circuit is comprehensive.

4. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 2, is characterized in that, e₂Expression formula be:

$e_2=U_{eq}{\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3$

Wherein, λ_eFor electricity sensitivity coefficient; P is the unit length coefficient of coup between power circuit and telegraph loop; l_sLine loop length for Approach phase; L is line loop length.

5. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 1, is characterized in that, THHF_UThe computing formula of permissible value is:

${\mathrm{THHF}}_U=\frac{\sqrt{3}e}{U\sqrt{{\left(16g_r{\mathrm{pl}}_s^{\′}{K}_e\right)}^2+{({\mathrm{\λ}}_e{g}_r{\mathrm{pK}}_e\frac{l_s}{l}\×{10}^3)}^2}}---\left(1\right).$

6. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 1, is characterized in that, comprise the following steps for the acquisition of the unit length coefficient of coup p between power circuit and telegraph loop in step B:

B1. obtain close to the geometric mean distance δ between equivalent distance a, power transmission wire average height b over the ground, Telecommunication Lines wire average height c over the ground, each wire of power transmission line;

B2. the unit length coefficient of coup p between computing electric line and telegraph loop.

7. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 6, is characterized in that, the computing formula of the unit length coefficient of coup p between power circuit and telegraph loop is:

$p=-\frac{5.6\mathrm{\δ}bc}{a^3}---\left(2\right).$

8. the computational methods of DC power transmission line phone harmonic wave forms coefficient restriction as claimed in claim 7, is characterized in that, in step 2, unit length coefficient of coup p can be obtained by formula (2); Working voltage U is the nominal voltage of DC power transmission line; The structural coefficient g of power circuit_r, 1/4.5 is taken for HVDC transmission line; Power circuit and telecommunication line Approach phase non-compensating length l '_sObtained by reality measurement; Electrically susceptible sense coefficient lambda_eCan be obtained by measuring, 0.8 is taken for HVDC transmission line; The line loop length l of Approach phase_sDetermine by actual track with line loop length l; The electrostatic screen COEFFICIENT K that power circuit is comprehensive_eThen can determine according to line levels, power line conductive linear diameter and discharge inception voltage and actual motion voltage, be determined by the form tabled look-up.