CN103913661B - Method for estimating influences on telecommunication cable E1 wire by electromagnetic disturbance - Google Patents

Abstract

The invention relates to a method for estimating influences on a telecommunication cable E1 wire by electromagnetic disturbance. The method comprises the steps of (1) measuring the electromagnetic environment of electric power telecommunication equipment in a transformer substation and in a convertor station, (2) simulating the electromagnetic environment, and (3) determining the error rate of the telecommunication cable E1 wire caused by the electromagnetic disturbance. The method can simulate the influences caused on the E1 wire of communication equipment cables of the transformer substation by confronting with the electromagnetic radiation disturbance under lightning stroke, system short circuit faults and other harsh conditions.

Description

A kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance

Technical field:

The present invention relates to a kind of appraisal procedure, be more particularly to the assessment that communication cable E1 line is affected by a kind of electromagnetic disturbance Method.

Background technology:

Bus, high-voltage device, chopper, disconnecting switch etc. are summarized once in the confined space of high voltage substation and current conversion station Equipment and protection, control, the secondary device such as communicate, and is the typical environment that combines of a strong and weak electricity.In transformer station's electromagnetic environment, one Secondary device mainly produces two class electromagnetic signals.One class is with the form of power-frequency voltage, electric current, electric field, magnetic field and radio interference The bistable electromagnetic signal existed；Another kind of is the Transient Electromagnetic signal mainly produced by thunderbolt, fault and switching manipulation.Communication sets Standby operating frequency frequency range more than KHz mostly is the lowest to the sensitivity of power frequency harassing and wrecking.And Transient Electromagnetic signal contains Having abundant radio-frequency component, easily by Space Coupling or CT, PT forms interference to secondary device.Therefore, measure and analyze wink State harassing and wrecking are the piths of scientific evaluation transformer station electromagnetic environment.For transformer station's Transient Electromagnetic harassing and wrecking, switching manipulation, thunder Hit the transient current of the primary system caused with fault and transient voltage is the source of all kinds of transient disturbance.The coupling way of electromagnetic disturbance Mainly there are two classes in footpath: a class be the primary system being coupled to communication equipment by CT, PT in the way of conduction transient current and Transient voltage；Another kind of space transient electric field and the transient magnetic field being to be coupled in the way of radiation communication equipment.

Should prevent from being externally entering underground or the aerial cable in power station, or enter power station from the transformer station isolated with power station Communication system and control cable, when transmission lines earth fault, thunderbolt or switching impulse effect, should prevent high pressure from producing it Harm.At present, communication line and the control circuit outreached typically use optical cable, and this problem can not consider to radiate its generation Impact.But the communication line of non-optical cable in transformer station, such as E1 line, (E1 line is the E1 line of 75 Europe resistant coaxial cable, typically Address is 2M line or E1 line, is the 2M connecting line between equipment.Ordinary circumstance be SDH and SHD BTS and BTS BTS and SHD SHD and BSC etc., as long as need 2M circuit to land or be cascaded to other equipment to use E1 line), study electromagnetic disturbance pair The error code impact that E1 line causes provides data support for follow-up safeguard procedures.

Summary of the invention:

It is an object of the invention to provide the appraisal procedure that communication cable E1 line is affected by a kind of electromagnetic disturbance, the method can mould The electromagnetic radiation harassing and wrecking that plan transformer substation communication equipment cable E1 line is faced under the harsh conditions such as thunderbolt, system short-circuit fault are made The impact become.

For achieving the above object, the present invention is by the following technical solutions: a kind of assessment electromagnetic disturbance is to communication cable E1 line The method of impact, said method comprising the steps of:

(1) electromagnetic environment of electric power communication device in transformer station and current conversion station is measured；

(2) described electromagnetic environment is simulated；

(3) determine that communication cable E1 line is affected the bit error rate caused by electromagnetic disturbance.

The a kind of of present invention offer assesses the method that communication cable E1 line is affected by electromagnetic disturbance, and described step (1) is described Measure and include measuring different electric pressure and the dissimilar transformer station electromagnetic disturbance characteristic to communication equipment, described electromagnetic disturbance Characteristic is by including that transformer station's power frequency electric field, power frequency magnetic field and switching manipulation produce and being shown by voltage probe and stored digital The stable state harassing and wrecking of communication equipment power supply in transformer station measured by ripple device；Receiver and all channel antenna are measured transformer station's electromagnetism and are disturbed The frequency domain data disturbed.

The a kind of of present invention offer assesses the method that communication cable E1 line is affected by electromagnetic disturbance, the survey of described electromagnetic environment Amount position includes master control room, communications equipment room, main transformer of transformer substation and transformer substation switch field.

The present invention provide another preferred a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, described step Suddenly (2) include harassing test platform, darkroom Radiating Facility or electrical fast transient (eft) assay device mould with Conducted Radio Frequency Intend described electromagnetic environment.

What the present invention provided another preferred a kind of assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described in penetrate Frequently conduction interference assay device includes RF transmitter, the injection being connected by power attenuator with described RF transmitter Pincers, respectively with equipment under test and one end of auxiliary equipment 2 of described injection clipper joint；The other end of described equipment under test passes through coupling Co-clip 1 is connected with auxiliary equipment 1；The other end of described auxiliary equipment 2 is connected with described coupling clip 2；Described coupling clip 1 and coupling Folder 2 connects the load in 50 Europe respectively.

What the present invention provided another preferred a kind of assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described secretly Room Radiating Facility includes anechoic chamber, the transmitting antenna being arranged on described anechoic chamber, and Field probe；Described transmitting antenna And between Field probe, it is sequentially connected with directional coupler, power generator, signal generator, controller and field intentisy meter；Described orientation coupling Clutch and described control device are connected with measuring instrument respectively；Described communication cable E1 is arranged on the testing stand in described anechoic chamber, Above and measuring at described transmitting antenna 1m and 3m respectively, the placing direction of described communication cable E1 includes being perpendicular to institute State the axis direction of testing stand and be parallel to the axis direction of described testing stand；The disposing way of described communication cable E1 line includes Be directly placed on described testing stand, table top adds earth plate and communication cable E1 line shielding layer grounding and table top add earth plate and pad High communication cable E1 by its shielding layer grounding；Described placing direction and disposing way combination in any.

The another preferred a kind of of present invention offer assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described electricity Clusters assay device includes the tested device that is arranged in ground reference plane by insulated leg and tested dress Put the described coupling device being arranged in described ground reference plane of connection and be connected with described coupling device be arranged on institute State the decoupling network in ground reference plane；Described coupling device and the electric fast transient being arranged in described ground reference plane Group pulse generator connects.

The another preferred a kind of of present invention offer assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described step Suddenly (3) to the extraction of described communication cable E1 parameter and determine that it is subject to by Agrawal field wire coupling model and transmission line theory Electromagnetic disturbance affects the bit error rate caused.

What the present invention provided another preferred a kind of assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described Agrawal field wire coupling model frequency domain equation is:

$\left\{\begin{array}{c}\frac{d{\stackrel{.}{U}}^s\left(x\right)}{\∂x}+R_0\stackrel{.}{I}\left(x\right)+\mathrm{j\ω}{L}_0\·\stackrel{.}{I}\left(x\right)+Z_g\left(\mathrm{\ω}\right)\·\stackrel{.}{I}\left(x\right)={\stackrel{.}{E}}_x^e(x,h)\\ \frac{d\stackrel{.}{I}\left(x\right)}{\∂x}+G_0{\stackrel{.}{U}}^s\left(x\right)+\mathrm{j\ω}{C}_0{\stackrel{.}{U}}^s\left(x\right)=0\end{array}---\left(1\right)\right.$

$\stackrel{.}{U}\left(x\right)={\stackrel{.}{U}}^s\left(x\right)-\underset{0}{\overset{h}{\∫}}{\stackrel{.}{E}}_z^e(x,h)\·\mathrm{dh}$

Wherein,U (x) andIt is respectively induced voltage, full voltage and total current；R₀, G₀, L₀, C₀And Z_g(ω) It is respectively the resistance of circuit unit length, conductance, inductance, electric capacity and the earth impedance,Level for incident electric fields Component；Described the earth impedance Z_g(ω) be:

$Z_g\left(\mathrm{\ω}\right)=\frac{\mathrm{j\ω}{\mathrm{\μ}}_0}{2\mathrm{\π}}1n\left(\frac{\frac{1}{\sqrt{\mathrm{j\ω}{\mathrm{\μ}}_0({\mathrm{\ϵ}}_r{\mathrm{\ϵ}}_0+\mathrm{\σ})}}+h}{h}\right)$

Wherein, μ₀For permeability of vacuum, ε_rFor relative dielectric constant, ε₀For vacuum absolute dielectric constant, σ is electrical conductivity, h Height for line-spacing ground.

The time-domain transmission line equation of formula (1) correspondence is:

$\left\{\begin{array}{c}\∂u^s(x,t)+R_{0}i(x,t)+L_0\frac{\∂i(x,t)}{\∂t}+Z_g\left(t\right)\⊗i(x,t)=E^e(x,h,t)\\ \frac{\∂i(x,t)}{\∂x}+G_0{u}^s(x,t)+C_0\frac{{\∂u}^s(x,t)}{\∂t}=0\end{array}---\left(2\right)\right.$

$u(x,t)=u^s(x,t)-\underset{0}{\overset{h}{\∫}}{E}_z^e(x,h,t)\·\mathrm{dh}$

In formula, Z_gT () represents the forms of time and space of the earth impedance.

The another preferred a kind of of present invention offer assesses the method that communication cable E1 line is affected by electromagnetic disturbance, described biography The extraction process of described communication cable E1 line parameter is by defeated lineation opinion:

If the top voltage x current of transmission line is respectively U₁、I₁Then following formula is had to set up at distance top x:

$\left\{\begin{array}{c}{U}_x=U_1\mathrm{cg\γx}-I_1{Z}_c\mathrm{sh\γx}\\ I_x=-\frac{U_1}{Z_c}\mathrm{sh\γx}+I_1\mathrm{ch\γx}\end{array}\right.---\left(3\right)$

For the transmission of transmission line, α is every kilometer of loss, β For phase coefficient；For the characteristic impedance of transmission line, R, L, G, C represent the electricity of transmission line unit length respectively Resistance, inductance, conductance, electric capacity；

On described transmission line, any point input impedance is:

$Z_{\mathrm{in}}=\frac{U_x}{I_x}=Z_c\frac{Z_l+Z_c\tanh \mathrm{\γl}}{Z_C+Z_l\tanh \mathrm{\γl}}---\left(4\right)$

Wherein, l is length of transmission line, Z_lTerminating load impedance for transmission line；

Can be obtained by transmission line input impedance formula (4): when load short circuits, i.e. Z_lWhen being zero, short-circuit impedance is Z_SC=Z_in =Z_Ctanhγl；When open-end, i.e. Z_lDuring for infinity, open-circuit impedance isDivided by impedance Analyzer, measures the open circuit short-circuit impedance of E1 line, determines ZC and γ, R, L, G, C the most successively；

Characteristic impedance Z_C=R_C+jX_CDetermination:

By Z_C ²=Z_SCZ_OC, and surveyed open circuit short-circuit impedance and write as plural form and be: Z_SC=R_S+jX_S,Z_OC=R_O+jX_O, thenCharacteristic impedance is derived according to data；

The determination of transmission γ=α+j β:

By $\sqrt{\frac{Z_{\mathrm{SC}}}{Z_{\mathrm{OC}}}}=\sqrt{\frac{R_S+j{X}_S}{R_O+j{X}_O}}=\tanh \mathrm{\γl}=\tanh \left[(\mathrm{\α}+\mathrm{j\β})l\right],$ Determine α, β；

The determination of R, L, G, C:

By $Z_C=\sqrt{\frac{R+\mathrm{j\ωL}}{G+\mathrm{j\ωC}}}=R_C+j{X}_C,$ $\mathrm{\γ}=\sqrt{(R+\mathrm{j\ωL})(G+\mathrm{j\ωC})}=\mathrm{\α}+\mathrm{j\β}$ R+j ω L=Z can be obtained_Cγ= (R_C+jX_C) (α+j β),

So that it is determined that:

$\left\{\begin{array}{c}R=\mathrm{\α}{R}_C-\mathrm{\β}{X}_C\\ L=\frac{\mathrm{\β}{R}_C+\mathrm{\α}{X}_C}{\mathrm{\ω}}\\ G=\frac{\mathrm{\α}{R}_C+\mathrm{\β}{X}_C}{{R_C}^2+{X_C}^2}\\ C=\frac{\mathrm{\β}{R}_C-\mathrm{\α}{X}_C}{\mathrm{\ω}({R_C}^2+{X_C}^2)}\\ \end{array}\right.---\left(5\right)$

Finally determine described communication cable E1 line signal waveforms and its bit error rate in simulation electromagnetic environment.

With immediate prior art ratio, the present invention provides technical scheme to have a following excellent effect:

1, the present invention utilizes the stable state of each position residing for method field survey transformer substation communication equipment of in-site measurement With transient state electromagnetic interference situation, provide minimum measurement standard for measurement in lab；

2, the method in the present invention can imitating substation communication equipment cable E1 line severe at thunderbolt, system short-circuit fault etc. In the case of the electromagnetic radiation that faced harass the impact caused；

3, the method in the present invention may extend to the equipment room data that transformer station other cables connect and harassed by electromagnetic radiation Impact measure；

4, the method for the present invention be follow-up take safeguard procedures propose numerical basis.

Accompanying drawing explanation

Fig. 1 is the method flow diagram of the present invention；

Fig. 2 is the radio-frequency field conduction interference assay device schematic diagram of the present invention；

Fig. 3 is the darkroom Radiating Facility schematic diagram of the present invention；

Fig. 4 is the electrical fast transient (eft) device schematic diagram of the present invention；

Fig. 5 is the E1 line interfered signal oscillogram in radio-frequency field conduction interference of the present invention test；

Fig. 6 is communication cable E1 line equivalent circuit schematic diagram of the present invention；

Fig. 7 is communication cable E1 line of the present invention and equivalent circuit thereof；

Fig. 8 is the resistance-frequency diagram of communication cable E1 line of the present invention；

Fig. 9 is communication cable E1 line inductance-frequency diagram of the present invention；

Figure 10 is communication cable E1 line conductance-frequency figure of the present invention；

Figure 11 is communication cable E1 line capacitance-frequency diagram of the present invention；

Figure 12 is communication cable E1 line signal waveforms of the present invention.

Detailed description of the invention

Below in conjunction with embodiment, the invention will be described in further detail.

Embodiment 1:

As shown in figs. 1-12, the appraisal procedure that communication cable E1 line is affected by the invention electromagnetic disturbance of this example,

The measurement of electromagnetic environment of electric power communication device in transformer station and current conversion station

(1) test content

By on-site measurement method, research different electric pressure, the dissimilar transformer station electromagnetic disturbance to communication equipment Characteristic, the electromagnetic disturbance characteristic produced including transformer station's power frequency electric field, power frequency magnetic field, switching manipulation etc..Utilize all channel antenna, The frequency domain data of transformer station's electromagnetic disturbance is measured by receiver.Transformer station is measured by voltage probe and digital storage oscilloscope The stable state harassing and wrecking of interior communication equipment power supply.In multiple electric pressures and different insulative type transformer station, in-site measurement with Stable state and transition effect are the electromagnetic environment of background.

(2) test equipment

Space bistable electromagnetic field measurement equipment:

● SCR3502 electromagnetic interference receiver, frequency band range 9kHz-2.75GHz；

● ZN30900 loop aerial, frequency band range 10kHz-30MHz；

● ZN30505 biconical antenna, frequency band range 30MHz-300MHz；

● ZN30503C log-periodic antenna, frequency band range 200MHz-3GHz；

Low frequency space electric field, the measurement equipment in magnetic field is:

● EFA300 electromagnetic field analysis instrument, frequency band range 5Hz-32kHz；

Wideband electromagnetic field field intensity indicator:

● EMC20 electromagnetic field measurements instrument, frequency band range 100kHz-3GHz.

(3) test position

The measurement position of each transformer station includes near master control room, communications equipment room, main transformer and in switch yard.

(4) test result

By receiver to 500kV transformer station, 500kV DC converter station, the measurement of 220kVGIS transformer station, draw Electromagnetic disturbance when normal steady state works in transformer station in 10kHz～2750MHz frequency range.Harassing and wrecking be concentrated mainly on 10kHz～ Near 150kHz scope, 1MHz, near 80MHz～100MHz, in addition near 200MHz, near 400MHz, near 1GHz and Also stronger harassing and wrecking are had near 2GHz.The level of electromagnetic disturbance is up to about 1V/m.

In communications equipment room, main harassing and wrecking concentrate on 45.3kHz～200kHz, and major electromagnetic harassing and wrecking source is data exchanges Equipment, main transformer, reactor etc..Therefore, communication equipment especially Wireless Telecom Equipment is taked mainly for above-mentioned frequency range or frequency Safeguard procedures.Electric field maximum amplitude is less than 1V/m.In master control room, major electromagnetic harassing and wrecking source be route exchange device, main transformer, Reactors etc., main harassing and wrecking frequency is 50.5kHz～120kHz, and maximum electromagnetic disturbance source strength is 100mV/m.Master in switch yard Wanting electromagnetic disturbance source is main transformer, reactor, and electromagnetic disturbance source frequency scope is 50kHz～100kHz, maximum electromagnetic disturbance source strength Degree 1V/m.

For emulation bad electromagnetic environment, E1 line is carried out error rate test

More than test is carried out under transformer station's normal operating conditions, and electromagnetic environment is not worst situation.When There is the situations such as switching manipulation, thunderbolt, short trouble in transformer station, the electromagnetic disturbance that communication equipment is faced can be more serious.This Patent simulates strong electromagnetic environment by laboratory equipment, and research communication cable is disturbed to cause the bit error rate by this type of to be affected, Foundation is provided for Effect of Anti jamming countermeasure.

(1) test equipment

● RF transmitter SCHAFFNERNSG2070RF-GENERATOR；

● coupling clip EM-KoppelzangeKEMZ801 (150kHz～230MHz)；

● electrical fast transient burst generating means SCHAFFNERNSG2025

● coupling clip CDN126COUPLINGCLAMP

● SCHAFFNER3 rice method compact anechoic chamber,

● SCHAFFNER compound log-periodic antenna CBL6140A

● summer optical error detector XG21282Mb/s

(2) test content and result

Conducted Radio Frequency harassing and wrecking pilot system is as in figure 2 it is shown, described Conducted Radio Frequency harassing and wrecking assay device includes that radio-frequency transmissions fills Put, by power attenuator be connected with described RF transmitter inject pincers, set with described the tested of injection clipper joint respectively Standby one end with auxiliary equipment 2；The other end of described equipment under test is connected with auxiliary equipment 1 by coupling clip 1；Described auxiliary sets The other end of standby 2 is connected with described coupling clip 2；Described coupling clip 1 and coupling clip 2 connect the load in 50 Europe respectively.

Added interference is 150kHz～100MHz, and intensity is 10V/m, and E1 line (overall length 30m) is placed in coupling clip (long 0.6m) In.Find that Error Detector occurs error code in interference for 80MHz～88MHz scope through repeated measurement.Fig. 5 is that added interference is Waveform between receiving end core and screen layer during 82.4MHz.Electric field intensity is adjusted to 3V/m and 1V/m, at whole 150kHz～ Without error code in 100MHz frequency range.Change the E1 line that overall length is 200m to be placed in coupling clip.Error code is found through above repeated measurement Instrument in interference for 70.7MHz(10V/m) near the bit error rate rise quickly, deadlock phenomenon even occurred.If will receive on Error Detector Sending out the screen layer single-point grounding of two-terminal, bit error rate reduction even disappears.

A large amount of tests show that the appearance of the bit error rate is relevant with the intensity of the length of E1 line and added interference, and table 1 counts Its relation.

Table 1 bit error rate occurs and E1 line length relation table

Darkroom radiation test, test layout is as it is shown on figure 3, described darkroom Radiating Facility includes anechoic chamber, setting Transmitting antenna and Field probe at described anechoic chamber,；It is sequentially connected with directional coupler, merit between described transmitting antenna and Field probe Rate generator, signal generator, controller and field intentisy meter；Described directional coupler and described control device are connected with measuring instrument； On the test wood table that described communication cable E1 is arranged in described anechoic chamber, and respectively at described transmitting antenna 1m and 3m Measuring, the placing direction of described communication cable E1 includes being perpendicular to the axis direction of described test wood table and being parallel to described The axis direction of test wood table；The disposing way of described communication cable E1 line includes being directly placed on described test wood table, table Face adds earth plate and communication cable E1 line shielding layer grounding and desktop adds earth plate and padded communication cable E1 line and shielded Layer ground connection；Described placing direction and disposing way combination in any.

Added interference is 10MHz～1GHz frequency sweep, field intensity 10V/m and fixed frequency 80MHz, 100MHz, 200MHz, 800MHz, At 1000MHz, the highest 40V/m of field intensity, E1 line is respectively placed in be tested at antenna 3m and 1m.In this test, do not occur Error code phenomenon.Result of the test is summarized in table 2.

Table 2E1 line darkroom radiation test summary sheet

Electrical fast transient (eft) is tested, and as shown in Figure 4, described electrical fast transient (eft) assay device includes leading to layout That crosses that the tested device that insulated leg is arranged in ground reference plane is connected with tested device is arranged on described ground connection with reference to flat Described coupling device on face and the decoupling network being arranged in described ground reference plane being connected with described coupling device；Institute The electrical fast transient burst generator stating coupling device and be arranged in described ground reference plane is connected.

The bit error rate situation that this experimental test E1 line (10m) occurs in the case of Transient Electromagnetic is harassed.Institute's making alive+ 500V is that error condition is serious, and voltage drop as little as+200V error code happens occasionally.In the case of-500V and-200V corresponding more than just During voltage, situation is preferable.Changing p-wire is 30m length, does not occurs that when error code ,+400V, error code is more when adding+200V interference ,+ During 500V, error code is serious.The number of bit errors that-200V ,-400V ,-500V occur accordingly is preferable compared with situation during above positive voltage.

Field wire coupling model theoretical calculation method

Transmission line transient process is solved based on time-domain finite element method.The equivalent circuit of E1 line is as shown in Figure 6.

Mathematical model:

Agrawal field wire coupling model is widely used in calculating overhead transmission line thunder and lightning induction voltage, its frequency domain side Cheng Wei

$\left\{\begin{array}{c}\frac{d{\stackrel{.}{U}}^s\left(x\right)}{\∂x}+R_0\stackrel{.}{I}\left(x\right)+\mathrm{j\ω}{L}_0\·\stackrel{.}{I}\left(x\right)+Z_g\left(\mathrm{\ω}\right)\·\stackrel{.}{I}\left(x\right)={\stackrel{.}{E}}_x^e(x,h)\\ \frac{d\stackrel{.}{I}\left(x\right)}{\∂x}+G_0{\stackrel{.}{U}}^s\left(x\right)+\mathrm{j\ω}{C}_0{\stackrel{.}{U}}^s\left(x\right)=0\end{array}---\left(1\right)\right.$

$\stackrel{.}{U}\left(x\right)={\stackrel{.}{U}}^s\left(x\right)-\underset{0}{\overset{h}{\∫}}{\stackrel{.}{E}}_z^e(x,h)\·\mathrm{dh}$

In above formulaU (x) andIt is respectively induced voltage, full voltage and total current, R₀, G₀, L₀, C₀And Z_g(ω) It is respectively the resistance of circuit unit length, conductance, inductance, electric capacity and the earth impedance,Level for incident electric fields Component.The biggest ground impedance Z_g(ω) be:

$Z_g\left(\mathrm{\ω}\right)=\frac{\mathrm{j\ω}{\mathrm{\μ}}_0}{2\mathrm{\π}}1n\left(\frac{\frac{1}{\sqrt{\mathrm{j\ω}{\mathrm{\μ}}_0({\mathrm{\ϵ}}_r{\mathrm{\ϵ}}_0+\mathrm{\σ})}}+h}{h}\right)$

Wherein, μ₀For permeability of vacuum, ε_rFor relative dielectric constant, ε₀For vacuum absolute dielectric constant, σ is electrical conductivity, h Height for line-spacing ground.

As can be seen from the above equation, greatly impedance is relevant with frequency, answers special handling during time-domain calculation.Formula (1) is right The time-domain transmission line equation answered is:

$\left\{\begin{array}{c}\∂u^s(x,t)+R_{0}i(x,t)+L_0\frac{\∂i(x,t)}{\∂t}+Z_g\left(t\right)\⊗i(x,t)=E^e(x,h,t)\\ \frac{\∂i(x,t)}{\∂x}+G_0{u}^s(x,t)+C_0\frac{{\∂u}^s(x,t)}{\∂t}=0\end{array}---\left(2\right)\right.$

$u(x,t)=u^s(x,t)-\underset{0}{\overset{h}{\∫}}{E}_z^e(x,h,t)\·\mathrm{dh}$

Z in formula_gT () represents the forms of time and space of the earth impedance.

Transmission line theory and E1 line parameter extraction:

Communication equipment is typically placed in independent communication room, and the connection with far-end is all by optical fiber, but photoelectricity turns After transformation becomes the signal of telecommunication, distribute to each equipment using signal by E1 line.2M cable conventional in communications equipment room is 75 Ω Model be junction cable T-75-8-D44-10, use E1 communication, model 10M-75OHM-8E1-2.2mm, single E1 communicates speed Rate 2.048Mbps.

(1) transmission line theory:

When wavelength is suitable with the length of E1 line, E1 line should be used as the research of uniform two conductor transmission line, and its parameter is with every single The numerical value of bit length represents.Wherein: x represents position；(with U (x+dx), x t) represents that signal is at transmission line x and x+ to U respectively Instantaneous voltage at dx；(x, t) (x+dx t) represents transient current to I respectively with I.Utilize the concept of distributed constant, will uniformly pass Defeated line is divided into the infinitesimal section of numerous dx length, and the distributed constant in each infinitesimal section is as it is shown in fig. 7, R, L, G, C represent respectively The resistance of transmission line unit length, inductance, conductance, electric capacity, constitute Γ type network, and the equivalent circuit of whole section of transmission line just becomes nothing Limit the cascade of many Γ type network.

If the top voltage x current of transmission line is respectively U₁、I₁Then following formula is had to set up at distance top x:

$\left\{\begin{array}{c}{U}_x=U_1\mathrm{cg\γx}-I_1{Z}_c\mathrm{sh\γx}\\ I_x=-\frac{U_1}{Z_c}\mathrm{sh\γx}+I_1\mathrm{ch\γx}\end{array}\right.---\left(3\right)$

Wherein,For the transmission of transmission line, α is every kilometer of loss, and β is Phase coefficient.Characteristic impedance for transmission line.

On transmission line, any point input impedance is:

$Z_{\mathrm{in}}=\frac{U_x}{I_x}=Z_c\frac{Z_l+Z_c\tanh \mathrm{\γl}}{Z_C+Z_l\tanh \mathrm{\γl}}---\left(4\right)$

Wherein, l is length of transmission line, Z_lTerminating load impedance for transmission line.

(2) extraction of E1 line distributed constant:

Can be obtained by transmission line input impedance formula: when load short circuits, i.e. Z_lWhen being zero, short-circuit impedance is Z_SC=Z_in= Z_Ctanhγl；When open-end, i.e. Z_lDuring for infinity, open-circuit impedance isUse impedance analysis Instrument, measures the open circuit short-circuit impedance of E1 line, releases ZC and γ the most successively, and then determine R, L, G, C.

Seek characteristic impedance Z_C=R_C+jX_C:

By Z_C ²=Z_SCZ_OC, and surveyed open circuit short-circuit impedance being write as plural form is Z_SC=R_S+jX_S,Z_OC=R_O+jX_O, thenCharacteristic impedance can be derived according to data.

Seek transmission γ=α+j β:

By $\sqrt{\frac{Z_{\mathrm{SC}}}{Z_{\mathrm{OC}}}}=\sqrt{\frac{R_S+j{X}_S}{R_O+j{X}_O}}=\tanh \mathrm{\γl}=\tanh \left[(\mathrm{\α}+\mathrm{j\β})l\right],$ α, β can be obtained.

Seek R, L, G, C:

By $Z_C=\sqrt{\frac{R+\mathrm{j\ωL}}{G+\mathrm{j\ωC}}}=R_C+j{X}_C,$ $\mathrm{\γ}=\sqrt{(R+\mathrm{j\ωL})(G+\mathrm{j\ωC})}=\mathrm{\α}+\mathrm{j\β}$

R+j ω L=Z can be obtained_Cγ=(R_C+jX_C) (α+j β),

Thus can obtain

$\left\{\begin{array}{c}R=\mathrm{\α}{R}_C-\mathrm{\β}{X}_C\\ L=\frac{\mathrm{\β}{R}_C+\mathrm{\α}{X}_C}{\mathrm{\ω}}\\ G=\frac{\mathrm{\α}{R}_C+\mathrm{\β}{X}_C}{{R_C}^2+{X_C}^2}\\ C=\frac{\mathrm{\β}{R}_C-\mathrm{\α}{X}_C}{\mathrm{\ω}({R_C}^2+{X_C}^2)}\\ \end{array}\right.---\left(5\right)$

Measuring E1 line in frequency is R during 100kHz～100Mhz_S、X_S、R_O、X_O, obtain under corresponding frequencies according to above-mentioned R, L, G, C.

(3) final data:

As illustrated in figs. 8-11, C is almost unchanged, 0.8e-11；R is incremented by with f, 0～1.05；L is almost unchanged, 0.4e-7；G is with f It is incremented by, 0～2e-5.

Assuming that line ground distance 20cm, thick 2 millimeters of line, frequency 80MHz, line length 1.9 meters, field intensity 10V/m, direction of an electric field is vertical In line, the signal graph simulation result of communication cable E1 is as shown in figure 12.

Finally should be noted that: above example is only in order to illustrate that technical scheme is not intended to limit, to the greatest extent The present invention has been described in detail by pipe with reference to above-described embodiment, and those of ordinary skill in the field are it is understood that still may be used Modify or equivalent with the detailed description of the invention to the present invention, and repair without departing from any of spirit and scope of the invention Changing or equivalent, it all should be contained in the middle of present claims scope.

Claims (8)

1. assess the method that communication cable E1 line is affected by electromagnetic disturbance for one kind, it is characterised in that: described method includes following step Rapid:

(1) electromagnetic environment of electric power communication device in transformer station and current conversion station is measured；

(2) described electromagnetic environment is simulated；

(3) determine that communication cable E1 line is affected the bit error rate caused by electromagnetic disturbance；

Described communication cable E1 line parameter is carried by described step (3) by Agrawal field wire coupling model and transmission line theory Take and determine that it is affected the caused bit error rate by electromagnetic disturbance；

Described Agrawal field wire coupling model frequency domain equation is:

$\left\{\begin{array}{c}\frac{d{\stackrel{\·}{U}}^s\left(x\right)}{\∂x}+R_0\stackrel{\·}{I}\left(x\right)+{\mathrm{j\ωL}}_0\·\stackrel{\·}{I}\left(x\right)+Z_g\left(\mathrm{\ω}\right)\·\stackrel{\·}{I}\left(x\right)={\stackrel{\·}{E}}_x^e(x,h)\\ \frac{d\stackrel{\·}{I}\left(x\right)}{\∂x}+G_0{\stackrel{\·}{U}}^s\left(x\right)+{\mathrm{j\ωC}}_0{\stackrel{\·}{U}}^s\left(x\right)=0\end{array}\right.---\left(1\right)$

$\stackrel{\·}{U}\left(x\right)={\stackrel{\·}{U}}^s\left(x\right)-\underset{0}{\overset{h}{\∫}}{\stackrel{\·}{E}}_z^e(x,h)\·dh$

Wherein,WithIt is respectively induced voltage, full voltage and total current；R₀, G₀, L₀, C₀And Z_g(ω) respectively For the resistance of circuit unit length, conductance, inductance, electric capacity and the earth impedance,Horizontal component for incident electric fields； Described the earth impedance Z_g(ω) be:

$Z_g\left(\mathrm{\ω}\right)=\frac{{\mathrm{j\ω\μ}}_0}{2\mathrm{\π}}ln\left(\frac{\frac{1}{\sqrt{{\mathrm{j\ω\μ}}_0({\mathrm{\ϵ}}_r{\mathrm{\ϵ}}_0+\mathrm{\σ})}}+h}{h}\right)$

Wherein, μ₀For permeability of vacuum, ε_rFor relative dielectric constant, ε₀For vacuum absolute dielectric constant, σ is electrical conductivity, and h is line Height away from ground；

The time-domain transmission line equation of formula (1) correspondence is:

$\left\{\begin{array}{c}\frac{\∂u^s(x,t)}{\∂x}+R_{0}i(x,t)+L_0\frac{\∂i(x,t)}{\∂t}+Z_g\left(t\right)\⊗i(x,t)=E^e(x,h,t)\\ \frac{\∂i(x,t)}{\∂x}+G_0{u}^s(x,t)+C_0\frac{\∂u^s(x,t)}{\∂t}=0\end{array}\right.---\left(2\right)$

$u(x,t)=u^s(x,t)-\underset{0}{\overset{h}{\∫}}{E}_z^e(x,h,t)\·dh$

In formula, Z_gT () represents the forms of time and space of the earth impedance.

The most as claimed in claim 1 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute State the electromagnetic disturbance spy that step (1) described measurement includes measuring different electric pressures and dissimilar transformer station to communication equipment Property, described electromagnetic disturbance characteristic is by including that transformer station's power frequency electric field, power frequency magnetic field and switching manipulation produce and passing through voltage Probe and digital storage oscilloscope measure the stable state harassing and wrecking of communication equipment power supply in transformer station；Receiver and all channel antenna Measure the frequency domain data of transformer station's electromagnetic disturbance.

The most as claimed in claim 2 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute The measurement position stating electromagnetic environment includes master control room, communications equipment room, main transformer of transformer substation and transformer substation switch field.

The most as claimed in claim 1 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute State step (2) to include harassing assay device, darkroom Radiating Facility or electrical fast transient (eft) test dress with Conducted Radio Frequency Put the described electromagnetic environment of simulation.

The most as claimed in claim 4 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute State Conducted Radio Frequency harassing and wrecking assay device to include RF transmitter, be connected with described RF transmitter by power attenuator Inject pincers, respectively with equipment under test and one end of auxiliary equipment 2 of described injection clipper joint；The other end of described equipment under test leads to Overcoupling folder 1 is connected with auxiliary equipment 1；The other end of described auxiliary equipment 2 is connected with coupling clip 2；Described coupling clip 1 and coupling Folder 2 connects the load in 50 Europe respectively.

The most as claimed in claim 4 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute State darkroom Radiating Facility and include anechoic chamber, the transmitting antenna being arranged on described anechoic chamber, and Field probe；Described transmitting Directional coupler, power generator, signal generator, controller and field intentisy meter it is sequentially connected with between antenna and Field probe；Described fixed Measuring instrument it is connected with respectively to bonder and described control device；Described communication cable E1 line is arranged in described anechoic chamber, Measuring on testing stand and respectively at described transmitting antenna 1m and 3m, the placing direction of described communication cable E1 line includes It is perpendicular to the axis direction of described testing stand and is parallel to the axis direction of described testing stand；Putting of described communication cable E1 line Mode includes being directly placed on described testing stand, table top adds earth plate and communication cable E1 line shielding layer grounding and table top adjunction Floor and padded communication cable E1 by its shielding layer grounding；Described placing direction and disposing way combination in any.

The most as claimed in claim 4 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute State tested device and quilt that electrical fast transient (eft) assay device includes being arranged in ground reference plane by insulated leg Survey device connect the coupling device being arranged in described ground reference plane and be connected with described coupling device be arranged on institute State the decoupling network in ground reference plane；Described coupling device and the electric fast transient being arranged in described ground reference plane Group pulse generator connects.

The most as claimed in claim 1 a kind of assess the method that communication cable E1 line is affected by electromagnetic disturbance, it is characterised in that: institute Stating transmission line theory to the extraction process of described communication cable E1 line parameter is:

If the top voltage x current of transmission line is respectively U₁、I₁Then following formula is had to set up at distance top x:

$\left\{\begin{array}{c}{U}_x=U_{1}ch\mathrm{\γ}x-I_1{Z}_{C}sh\mathrm{\γ}x\\ I_x=-\frac{U_1}{Z_C}sh\mathrm{\γ}x+I_{1}ch\mathrm{\γ}x\end{array}\right.---\left(3\right)$

Wherein,For the transmission of transmission line, α is every kilometer of loss, and β is phase shift system Number；For the characteristic impedance of transmission line, R, L, G, C represent respectively the resistance of transmission line unit length, inductance, Conductance, electric capacity；

On described transmission line, any point input impedance is:

$Z_{in}=\frac{U_x}{I_x}=Z_C\frac{Z_l+Z_C\tanh \mathrm{\γ}l}{Z_C+Z_l\tanh \mathrm{\γ}l}---\left(4\right)$

Wherein, l is length of transmission line, Z_lTerminating load impedance for transmission line；

Can be obtained by transmission line input impedance formula (4): when load short circuits, i.e. Z_lWhen being zero, short-circuit impedance is Z_SC=Z_in=Z_C tanhγl；When open-end, i.e. Z_lDuring for infinity, open-circuit impedance isPass through impedance analysis Instrument, measures the open circuit short-circuit impedance of E1 line, determines Z the most successively_CAnd γ, R, L, G, C；

Characteristic impedance Z_C=R_C+jX_CDetermination:

By Z_C ²=Z_SCZ_OC, and surveyed open circuit short-circuit impedance and write as plural form and be:

Z_SC=R_S+jX_S,Z_OC=R_O+jX_O, thenSpy is derived according to data Property impedance；

The determination of transmission γ=α+j β:

ByDetermine α, β；

The determination of R, L, G, C:

By

R+j ω L=Z can be obtained_Cγ=(R_C+jX_C) (α+j β),

So that it is determined that:

$\left\{\begin{array}{c}R={\mathrm{\αR}}_C-{\mathrm{\βX}}_C\\ L=\frac{{\mathrm{\βR}}_C+{\mathrm{\αX}}_C}{\mathrm{\ω}}\\ G=\frac{{\mathrm{\αR}}_C+{\mathrm{\βX}}_C}{{R_C}^2+{X_C}^2}\\ C=\frac{{\mathrm{\βR}}_C-{\mathrm{\αX}}_C}{\mathrm{\ω}({R_C}^2+{X_C}^2)}\end{array}\right.---\left(5\right)$

Finally determine described communication cable E1 line signal waveforms and its bit error rate in simulation electromagnetic environment.