CN106059692A - Path loss modeling method for transformer substation environment - Google Patents

Abstract

The invention provides a path loss modeling method for a transformer substation environment. The method comprises the following steps of establishing a data measurement scheme, collecting data, establishing a path loss model and determining parameters of the path loss model. In the technical scheme provided by the invention, a large amount of sample data is not needed, the path loss property of a wireless signal in a transformer substation can be determined precisely and effectively, and the parameters obtained through computation can be better coincident to the measured data of a wireless channel.

Description

A kind of path loss modeling method of substation

Technical field

The present invention relates to electric power wireless communication technology field, the path loss modeling of a kind of substation Method.

Background technology

Using electrical networks at different levels as the intelligent grid on rack basis, make use of the messaging platforms that every new technique is set up, Achieve many integrated managemenies such as electric power transmission, operation of power networks and power businesses.As realizing power information transmission The radio communication of important means, it is achieved that quickly, communicate easily, be also faced with lot of challenges simultaneously.

As a example by high voltage substation applied environment, operationally can produce electromagnetism due to high voltage substation electrical equipment and do Disturb, the Wireless Telecom Equipment being placed in the transformer station that electromagnetic environment is the most severe, by by electromagnetic interference in various degree, makes There is error code or packet loss in equipment communication, can cause the interruption of communication time serious.

Wireless Telecom Equipment is arranged in transformer station, the radio wave propagation characteristic of corresponding band will do concrete research and divide Analysis, still lacks effective assessment models and analysis means at present in the application of power system complex electromagnetic environment.

For another example, in in radio communication, the prior art of radio wave propagation characteristic is analyzed, main employing theoretical simulation and scene are surveyed Measure two class methods.Theoretical simulation method defers to EM theory, is modeled the detailed problem of communication environments by Computational electromagnetics, The propagation characteristic of signal is carried out simulation and prediction, but in transformer station, space is very big, and electrical equipment is many and complicated, uses meter Calculate electromagnetic method to be limited by computer speed and memory size, it is achieved more difficulty.

In the on-site measurement method and for example generally used in Practical Project, need to establish the radio channel path of specific environment Footpath loss model.In the middle of path loss model formula, characterize important parameter path-loss factor n and the standard deviation sigma of path loss Can not be directly obtained by apparatus measures, it usually needs carrying out curve fitting actual measurement data obtains the estimation of its parameter Value.

In conventional path loss model the computational methods of parameter have moments estimation, Minimum Mean Square Error (MMSE), accumulation and (CUSUM), linear regression analysis etc.:

The population distribution characteristic present effect of moment estimation method therein is poor, only could protect when sample size is bigger Demonstrate,prove the Optimality of this algorithm.

And the shortcoming of lowest mean square difference method is result of calculation it cannot be guaranteed that the remainder error of value after Gu Jiing and sample value It is 0.

Accumulation and method computing formula are more complicated, it is achieved relatively complicated.

In linear regression analysis, select which kind of factor and this factor to use which kind of expression formula simply one to speculate, be faced with The multiformity of the factor and the immeasurability of some factor, the linear regression analysis caused is the most unavailable.

The computational methods of these several parameters have the advantage of himself, but all can not be fine with the measured data of wireless channel It coincide.Therefore, for meeting the needs of prior art, the present invention provides a kind of modeling method, and its model parameter calculation is simple and convenient.

Summary of the invention

For meeting the needs of prior art, the present invention provides the radio channel path loss modeling side of a kind of substation Method, it thes improvement is that, described modeling method includes:

Step 1, set up DATA REASONING scheme；

Step 2, collection data；

Step 3, set up path loss model；

Step 4, determine the parameter of path loss model.

Further, in described step (1), described DATA REASONING scheme includes:

(1-1) determine wireless measured signal source, and produce wireless measured signal with signal source and transmitting antenna；

(1-2) the transmitting power of described wireless measured signal be 0dBm, frequency be 300MHz-3GHz；

(1-3) analyze, with spectrum analyzer, the wireless measured signal that reception antenna receives.

Further, described spectrum analyzer uses peak detection mode or quasi-peak value detecting way；

The setting of the bandwidth of described spectrum analyzer includes:

When I, wireless measured signal frequency are 300MHz-1GHz, a width of 1kHz of resolution belt of described spectrum analyzer, depending on Bandwidth is set to 10kHz；

When II, wireless measured signal frequency are 1GHz-3GHz, a width of 10kHz of resolution belt of described spectrum analyzer, depending on Bandwidth is set to 100kHz.

Further, in described step (2), measure the reception power of the wireless measured signal at interval of 3m, obtain reality The reception of wireless signals vector power A measured.

Further, in described step (3), according to large scale decline theory, set up the path loss as shown in following formula (1) Model PL (d):

$PL\left(d\right)=PL\left(d_0\right)+10nlog\left(\frac{d}{d_0}\right)+X_{\mathrm{\σ}}---\left(1\right)$

Wherein, n is path-loss factor；X_σBe average be 0, standard deviation is the Gaussian random variable of σ；D is dual-mode antenna Between distance；d₀For launching the distance between antenna distance reference point；PL(d₀) it is that launch point damages to the path between reference point Consumption, unit is dB.

Further, in described step (4), path selection fissipation factor n and standard deviation sigma in the range of 0-10, according under Formula (2) calculates corresponding pre-estimation and receives power P_r(d):

$\begin{array}{c}{P}_r\left(d\right)=P_t-PL\left(d\right)\\ =P_t-PL\left(d_0\right)-10n\log \left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}\\ =P\left(d_0\right)-10n\log \left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}\end{array}---\left(2\right)$

In formula, P_t: wireless measured signal launches power；P(d₀): reference point receives power.

Further, in described step (4), pre-estimation is asked to receive power P_rD () measures reception of wireless signals merit with actual The inner product of rate vector A；

According to matching pursuit algorithm, determine described path-loss factor n corresponding to described maximum inner product and described standard deviation sigma Value, the path loss model of matching substation.

With immediate prior art ratio, the present invention has a following excellent effect:

In the modeling method that the present invention provides, the measurement of initial data realizes simple, and without substantial amounts of sample, it can Accurately, efficient the parameter of wireless signal path loss model in transformer station, and its data pole obtained with field survey are calculated Good coincide, and Minimum Mean Square Error, accumulation and the method traditional relative in prior art substantially reduces in path loss model joins Numerical value deviation, it is ensured that the standardization of path loss model, improves the estimated value to radio channel path loss characteristic, reduces Path loss values estimation difference.

Accompanying drawing explanation

The overall plan implementing procedure figure that Fig. 1 provides for the present invention；

Fig. 2 is that the present invention is at the actual cloth point diagram measuring reception of wireless signals power of 110kV transformer station；

Fig. 3 is that the present invention is at the actual cloth point diagram measuring reception of wireless signals power of 220kV transformer station；

Fig. 4 is the flow chart that the present invention calculates radio channel path loss model parameter；

Fig. 5 is that the present invention uses multiple method estimated path loss figure at 110kV transformer station, 430MHz frequency；

Fig. 6 is that the present invention uses multiple method estimated path loss figure at 220kV transformer station, 430MHz frequency；

Fig. 7 is that the present invention uses multiple method estimated path loss figure at 110kV transformer station, 470MHz frequency；

Fig. 8 is that the present invention uses multiple method estimated path loss figure at 220kV transformer station, 470MHz frequency；

Fig. 9 is that the present invention uses multiple method estimated path loss figure at 110kV transformer station, 2.4GHz frequency；

Figure 10 is that the present invention uses multiple method estimated path loss figure at 220kV transformer station, 2.4GHz frequency.

Detailed description of the invention

The path loss modeling method provided the present invention below with reference to accompanying drawing is described in further detail.

The overall plan implementing procedure figure of the present invention as shown in Figure 1, the modeling of the path loss model that the present invention provides In method, comprise the following steps:

(1) the raw measurement data measurement scheme of path loss model is set up；

As shown in Figures 2 and 3, it is respectively at the actual cloth measuring reception of wireless signals power of 110kV and 220kV transformer station Point diagram, during measuring, wireless measured signal source is placed in the communication room of transformer station, and position immobilizes, and launches equipment Being become with transmission antenna group by signal source, signal source have employed AV1441A radio-frequency signal generator, launches antenna and has been respectively adopted suitable Log-periodic antenna and 2.4GHz monopole antenna for 200MHz-2GHz frequency range.

The transmitting power arranging wireless measured signal is 0dBm, and have selected 430MHz, 470MHz, 2.4GHz tri-respectively Frequency to be measured.

Reception equipment is made up of spectrum analyzer N1996A and the reception antenna of Shi De scientific & technical corporation, wherein, and reception antenna Have employed the log-periodic antenna that Ainfoinc company produces, model is DS-3300, and bandwidth coverage is 30MHz-3GHz.

Spectrum analyzer detecting way uses peak detection, for 430MHz, 470MHz frequency, the resolution of spectrum analyzer Rate bandwidth (RBW) is 1kHz, and video bandwidth (VBW) is 10kHz, and for 2.4GHz frequency, the RBW of spectrum analyzer is 10kHz, VBW is 100kHz.

(2) build measurement system, gather data；

Wireless measured signal receiving position major electromagnetic near sensitive equipment layout along transformer station, determines one at interval of 3m Individual measurement point, measures the reception power of wireless measured signal successively, obtains actual measurement reception of wireless signals signal power vector A.Owing to measuring the particular/special requirement such as environment and place restriction, in the present embodiment, each transformer station have chosen 10 and measures point, vector A It is expressed as:

A=[a₁、a₂、…、a₁₀]。

(3) according to large scale decline theory, path loss model is set up；

Set up launch point as shown in following formula (1) model to path loss PL (d) between receiving position:

$PL\left(d\right)=PL\left(d_0\right)+10nlog\left(\frac{d}{d_0}\right)+X_{\mathrm{\σ}}---\left(1\right)$

Wherein, n is path-loss factor；X_σBe average be 0, standard deviation is the Gaussian random variable of σ；D is dual-mode antenna Between distance；d₀For launching the distance between antenna distance reference point；PL(d₀) it is that launch point damages to the path between reference point Consumption, unit is dB.

Launch point in described path loss model is to the path loss PL (d between reference point₀), can field test；

Or, the free space loss shown in (2) determines as the following formula:

$PL\left(d_0\right)=20log\left(\frac{4{\mathrm{\πd}}_0}{\mathrm{\λ}}\right)---\left(2\right)$

In formula, d₀For launching the distance between antenna distance reference point；The wavelength X of λ=c/f, i.e. electromagnetic wave is equal to light velocity c Divided by frequency f.

(4) parameter in path loss model is determined；

(I) parameter calculation flow chart as shown in Figure 4, makes path-loss factor n and standard deviation sigma become within the specific limits Change, obtain corresponding pre-estimation respectively and receive power P_r(d)。

Path-loss factor n and standard deviation sigma change in the range of 0-10, according to different n and σ values, according to the following formula (3) Calculate corresponding pre-estimation and accept power P_r(d):

$\begin{array}{c}{P}_r\left(d\right)=P_t-PL\left(d\right)\\ =P_t-PL\left(d_0\right)-10n\log \left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}\\ =P\left(d_0\right)-10n\log \left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}\end{array}---\left(3\right)$

In formula, P_t: wireless measured signal launches power；P(d₀): reference point receives power.

(II) based on matching pursuit algorithm, P is calculated_r(d) and the actual inner product measuring reception of wireless signals vector power A, Find out the path-loss factor n corresponding to maximum inner product and standard deviation sigma, simulate the optimal path loss of transformer station's specific environment Model.

Fig. 5-Figure 10 be respectively the present invention be respectively adopted traditional Minimum Mean Square Error (MMSE), accumulation and (CUSUM) and The multiple methods such as the estimation method (New method) according to above-mentioned path loss model parameters, to actual measurement path loss (Test Data) comparison of model parameter estimation result, transformer station's sampling environment is:

110kV transformer station, 430MHz frequency；

220kV transformer station, 430MHz frequency；

110kV transformer station, 470MHz frequency；

220kV transformer station, 470MHz frequency；

110kV transformer station, 2.4GHz frequency；

220kV transformer station, 2.4GHz frequency.

Comparison diagram demonstrate in the substation that the inventive method calculates radio channel path loss model parameter with The actual path loss parameter values measured is closest, has optimum efficiency.

Above example is only in order to illustrate that technical scheme is not intended to limit, although with reference to above-described embodiment pair The present invention has been described in detail, and the detailed description of the invention of the present invention still can be entered by those of ordinary skill in the field Row amendment or equivalent, these are without departing from any amendment of spirit and scope of the invention or equivalent, all in application Within the claims of the present invention awaited the reply.

Claims (7)

1. the path loss modeling method of a substation, it is characterised in that described modeling method includes:

Step 1, set up DATA REASONING scheme；

Step 2, collection data；

Step 3, set up path loss model；

Step 4, determine the parameter of path loss model.

2. modeling method as claimed in claim 1, it is characterised in that in described step (1), described DATA REASONING scheme bag Include:

(1-1) determine wireless measured signal source, and produce wireless measured signal with signal source and transmitting antenna；

(1-2) the transmitting power of described wireless measured signal be 0dBm, frequency be 300MHz-3GHz；

(1-3) analyze, with spectrum analyzer, the wireless measured signal that reception antenna receives.

3. modeling method as claimed in claim 2, it is characterised in that described spectrum analyzer uses peak detection mode or standard Peak detection mode；

The setting of the bandwidth of described spectrum analyzer includes:

When I, wireless measured signal frequency are 300MHz-1GHz, a width of 1kHz of resolution belt of described spectrum analyzer, video tape Width is set to 10kHz；

When II, wireless measured signal frequency are 1GHz-3GHz, a width of 10kHz of resolution belt of described spectrum analyzer, video tape Width is set to 100kHz.

4. modeling method as claimed in claim 1, it is characterised in that in described step (2), measure and treat at interval of the wireless of 3m Survey the reception power of signal, obtain the reception of wireless signals vector power A of actual measurement.

5. modeling method as claimed in claim 1, it is characterised in that in described step (3), according to large scale decline theory, Foundation path loss model PL (d) as shown in following formula (1):

$PL\left(d\right)=PL\left(d_0\right)+10nlog\left(\frac{d}{d_0}\right)+X_{\mathrm{\σ}}---\left(1\right)$

Wherein, n is path-loss factor；X_σBe average be 0, standard deviation is the Gaussian random variable of σ；D is between dual-mode antenna Distance；d₀For launching the distance between antenna distance reference point；PL(d₀) it is launch point to the path loss between reference point, single Position is dB.

6. modeling method as claimed in claim 1, it is characterised in that in described step (4), path selection in the range of 0-10 Fissipation factor n and standard deviation sigma, (2) calculate corresponding pre-estimation and receive power P according to the following formula_r(d):

$\begin{array}{c}{P}_r\left(d\right)=P_t-\mathrm{PL}\left(d\right)\\ =P_t-\mathrm{PL}\left(d_0\right)-10n\log \left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}\end{array}$

$=P\left(d_0\right)-10nlog\left(\frac{d}{d_0}\right)-X_{\mathrm{\σ}}---\left(2\right)$

In formula, P_t: wireless measured signal launches power；P(d₀): reference point receives power.

7. modeling method as claimed in claim 1, it is characterised in that in described step (4), asks pre-estimation to receive power P_r(d) With the inner product that reality measures reception of wireless signals vector power A；

According to matching pursuit algorithm, determine described path-loss factor n corresponding to described maximum inner product and described standard deviation sigma Value, the path loss model of matching substation.