CN103728344B - A kind of method of monitoring pollution severity of insulators damp degree - Google Patents

Abstract

The invention discloses a kind of method of monitoring pollution severity of insulators damp degree, comprise the steps: that S1 is in metering circuit, gather the voltage signal of fixed value resistance and the voltage signal of power supply; S2 takes absolute value after being subtracted each other by the initial phase angle of above-mentioned two voltage signals and obtains phase angle difference θ; S3 obtains the relational expression of the equivalent resistance Rx of phase angle difference θ and pollution severity of insulators; S4, according to the change of phase angle difference, obtains pollution severity of insulators damp degree.Measuring error of the present invention is little, equipment manufacturing cost is cheap, analysis on monitoring result is simple.

Description

A kind of method of monitoring pollution severity of insulators damp degree

Technical field

The present invention relates to electric transmission line isolator on-line monitoring field, be specifically related to a kind of method of monitoring pollution severity of insulators damp degree.

Background technology

For a long time, the pollution severity of insulators on transmission line of electricity makes moist, and generation pollution flashover and lightning stroke trip accident happen occasionally, and cause heavy losses to national economy.According to statistics, the insulation flashover accident number of times that filth causes accounts for second in the total accident number of times of current electrical network, be only second to lightening hazard, and the loss that pollution flashover accident causes is 10 times of lightening hazard.Therefore, pollution flashover accident has become the serious threat of electric power netting safe running.Timely understanding pollution severity of insulators damp degree, for take precautions against pollution flashover accident there is vital role, for the cleaning works of pollution severity of insulators provides guidance.

At present, the main method of monitoring pollution severity of insulators damp degree has: image treating, and utilize computer disposal by the picture of camera shooting pollution severity of insulators damp degree, this method error is larger; Characteristic signal (as low frequency signal, microwave signal, the ultrasonic signal) method sent during monitoring insulator surface flashover, this method needs high-accuracy sensor when obtaining low frequency signal, expensive, and characteristic signal obtains insufficient, then error is large; The leakage current method that monitoring pollution severity of insulators flows through, this method needs large memory capacity, analyzes difficulty.

Summary of the invention

In order to overcome the shortcoming of prior art existence with not enough, the invention provides a kind of method of monitoring pollution severity of insulators damp degree.

The present invention adopts following technical scheme:

Monitor a method for pollution severity of insulators damp degree, comprise the steps:

S1, in metering circuit, gathers the voltage signal of fixed value resistance and the voltage signal of power supply;

S2 takes absolute value after being subtracted each other by the initial phase angle of above-mentioned two voltage signals and obtains phase angle difference θ;

S3, according to the computing formula of phase angle difference θ, obtains the relational expression of the equivalent resistance Rx of phase angle difference θ and pollution severity of insulators;

The computing formula of described phase angle difference θ: $\mathrm{\θ}=\arctan \frac{1}{R_s[\frac{1}{\mathrm{\ω}{C}_s{R}_x^2}+\mathrm{\ω}{C}_s]+\frac{1}{\mathrm{\ω}{C}_s{R}_x}}$

Wherein, Rs represents fixed value resistance, and ω is angular frequency, and Cs represents definite value electric capacity, and Rx is the equivalent resistance of pollution severity of insulators;

By Rs=1000 Ω, angular frequency=800 π, definite value electric capacity Cs=50nF is updated to the computing formula of phase angle difference θ, and the relational expression obtaining the equivalent resistance Rx of phase angle difference θ and pollution severity of insulators is as follows:

$\mathrm{\θ=arctan}\frac{1}{8\×{10}^6{(\frac{1}{R_x}+5\×{10}^{-4})}^2-1.8744};$

S4, according to the change of phase angle difference, obtains pollution severity of insulators damp degree.

Described metering circuit is made up of the equivalent resistance of power supply, fixed value resistance, definite value electric capacity and pollution severity of insulators, and wherein, definite value electric capacity is connected with fixed value resistance, power supply successively with after the equivalent resistance parallel connection of pollution severity of insulators.

Described power supply is sine-wave power, and frequency is 400Hz, and voltage magnitude is 5V.

Described fixed value resistance is made up of more than one resistant series or in parallel or series-parallel connection.

Described definite value electric capacity is made up of more than one capacitances in series or in parallel or series-parallel connection.

Beneficial effect of the present invention:

(1) provide a kind of new mode to monitor pollution severity of insulators to make moist situation, The method avoids directly monitoring insulator surface Leakage Current, in the situation of making moist macroscopically better can holding pollution severity of insulators;

(2) method of this situation of making moist based on phase angle difference monitoring pollution severity of insulators, the measuring error of its monitoring is little, and equipment manufacturing cost is cheap, the features such as interpretation of result is simple.

Accompanying drawing explanation

Fig. 1 is metering circuit connection diagram of the present invention;

Fig. 2 is workflow diagram of the present invention;

Fig. 3 is that to apply the present invention to one group of close value of salt in embodiment be 0.1mg/cm ², grey close value is 0.6mg/cm ²under pollution severity of insulators to make moist test figure figure.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

Embodiment

As shown in Figure 2, a kind of method of monitoring pollution severity of insulators damp degree, comprises the steps:

S1 arranges insulator surface electrode, by in the Electrode connection that arranges as shown in Figure 1 metering circuit, described metering circuit is made up of the equivalent resistance Rx of power supply Us, fixed value resistance Rs, definite value electric capacity Cs and pollution severity of insulators, wherein, definite value electric capacity is connected with fixed value resistance, power supply successively with after the equivalent resistance parallel connection of pollution severity of insulators, and in figure, Ux represents the voltage of the equivalent resistance Rx of pollution severity of insulators.

Circuit as shown in Figure 1, can obtain resulting impedance in circuit:

$Z=R_s+R_x//\frac{1}{\mathrm{j\ω}{C}_s}=[R_s+\frac{1/R_s}{{(1/R_x)}^2+{\left(\mathrm{\ω}{C}_s\right)}^2}]-j\frac{\mathrm{\ω}{C}_s}{{(1/R_x)}^2+{\left(\mathrm{\ω}{C}_s\right)}^2}$

In above-mentioned formula, j represents imaginary unit, and according to the expression formula of above-mentioned resulting impedance, the formula that can calculate phase angle difference θ in metering circuit is:

$\mathrm{\θ}=|-\arctan \frac{\frac{\mathrm{\ω}{C}_s}{{(1/R_x)}^2+{\left(\mathrm{\ω}{C}_s\right)}^2}}{R_s+\frac{1/R_x}{{(1/R_x)}^2+{\left(\mathrm{\ω}{C}_s\right)}^2}}|=\arctan \frac{1}{R_s[\frac{1}{\mathrm{\ω}{C}_s{R}_x^2}+\mathrm{\ω}{C}_s]+\frac{1}{\mathrm{\ω}{C}_s{R}_x}}$

Described power supply Us provides sine-wave power, and frequency is 400Hz, and amplitude is 5V, and the resistance of described fixed value resistance Rs is 1000 Ω, and the capacitance of described definite value electric capacity Cs is 50nF.

The present embodiment adopts pollution severity of insulators to be configured with salt close (Nacl) and ash close (zeyssatite), and in the filth of configuration, close/grey close ratio of salt is 1:6.

The filthy night configured is coated onto on insulator surface equably, and then in growth cabinet, carries out water spray experiment.

S2 gathers the voltage signal Um of fixed value resistance, the voltage signal of power taking source Us.

S3 gets its absolute value after the initial phase angle of the voltage signal Um of fixed value resistance and the initial phase angle of power supply Us being subtracted each other, and obtains phase angle difference θ,

The computing formula of described phase angle difference θ is:

$\mathrm{\θ}=\arctan \frac{1}{R_s[\frac{1}{\mathrm{\ω}{C}_s{R}_x^2}+\mathrm{\ω}{C}_s]+\frac{1}{\mathrm{\ω}{C}_s{R}_x}}$

Wherein, fixed value resistance Rs is 1000 Ω, and angular frequency is 800 π, the equivalent resistance of definite value electric capacity Cs to be 50nF, Rx be pollution severity of insulators.

When water spray test, according to the amount of water spray, record phase angle difference θ at set intervals.

S4 makes moist in test at pollution severity of insulators, along with the change of pollution severity of insulators damp degree, the equivalent resistance also and then constantly change of pollution severity of insulators, according to the formula in S3, the equivalent resistance change of pollution severity of insulators, phase angle difference also and then changes thereupon, is 1000 Ω by fixed value resistance Rs, angular frequency is 800 π, and definite value electric capacity Cs is the relational expression obtaining phase angle difference and pollution severity of insulators equivalent resistance during 50nF is updated in S3 formula:

$\mathrm{\θ=arctan}\frac{1}{8\×{10}^6{(\frac{1}{R_x}+5\×{10}^{-4})}^2-1.8744}$

The quantitative relationship between pollution severity of insulators damp degree and phase angle difference θ can be obtained.When pollution severity of insulators is dry, its equivalent resistance Rx value is very large, and its phase angle difference θ is also very large; Pollution severity of insulators is by the time of tide, and its equivalent resistance Rx value reduces, and its phase angle difference θ also reduces.

As shown in Figure 3, it is 0.1mg/cm2 that this method is applied to one group of close value of salt, and grey close value is that pollution severity of insulators under 0.6mg/cm2 makes moist test figure figure:

As can be seen from Figure 3, along with the increase of injection flow rate, phase angle difference first reduces, rear increase.When not spraying water, pollution severity of insulators is in drying regime, and the equivalent resistance Rx of pollution severity of insulators is very large, and the computing formula according to above-mentioned phase angle difference θ can obtain, and Rx is very large, and phase angle difference θ is just large; Along with increasing of water spray, the equivalent resistance Rx of pollution severity of insulators starts to decline, and phase angle difference θ also starts to decline; When pollution severity of insulators saturate moisture condition, its equivalent resistance Rx drops to minimum, and its corresponding phase angle difference θ also drops to minimum; Continue water spray again, pollution severity of insulators starts to run off, and at leisure, the equivalent resistance of insulator surface increases, and phase angle difference θ also starts to increase, until insulator surface is in state of insulation.In Fig. 3, the situation of making moist of pollution severity of insulators clearly can reflect by phase angle difference, and has accurately and reliably, and precision is high, analyzes simple.

Make moist along with pollution severity of insulators according to above-mentioned θ and change, under normal circumstances, θ is in certain threshold value, when exceeding this threshold value, representing that the insulating property of insulator reduce, arranging warning function.

Above-described embodiment is the present invention's preferably embodiment; but embodiments of the present invention are not limited by the examples; change, the modification done under other any does not deviate from Spirit Essence of the present invention and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (4)

1. monitor a method for pollution severity of insulators damp degree, it is characterized in that, comprise the steps:

S1, in metering circuit, gets the voltage signal of fixed value resistance and the voltage signal of power supply;

S2 takes absolute value after being subtracted each other by the initial phase angle of above-mentioned two voltage signals and obtains phase angle difference θ;

S3, according to the computing formula of phase angle difference θ, obtains the relational expression of the equivalent resistance Rx of phase angle difference θ and pollution severity of insulators;

The computing formula of described phase angle difference θ: $\mathrm{\θ}=arctan\frac{1}{R_s\[\frac{1}{{\mathrm{\ωC}}_s{R}_x^2}+{\mathrm{\ωC}}_s\]+\frac{1}{{\mathrm{\ωC}}_s{R}_x}}$

Wherein, Rs represents fixed value resistance, and ω is angular frequency, and Cs represents definite value electric capacity, and Rx is the equivalent resistance of pollution severity of insulators;

By Rs=1000 Ω, angular frequency=800 π, definite value electric capacity Cs=50nF is updated to the computing formula of phase angle difference θ, and the relational expression obtaining the equivalent resistance Rx of phase angle difference θ and pollution severity of insulators is as follows:

$\mathrm{\θ}=arctan\frac{1}{8\×{10}^6{(\frac{1}{R_x}+5\×{10}^{-4})}^2-1.8744};$

S4, according to the change of phase angle difference, obtains pollution severity of insulators damp degree;

Described metering circuit is made up of the equivalent resistance of power supply, fixed value resistance, definite value electric capacity and pollution severity of insulators, and wherein, definite value electric capacity is connected with fixed value resistance, power supply successively with after the equivalent resistance parallel connection of pollution severity of insulators.

2. method according to claim 1, is characterized in that, power supply is sine-wave power, and frequency is 400Hz, and voltage magnitude is 5V.

3. method according to claim 1, is characterized in that, described fixed value resistance is made up of more than one resistant series or in parallel or series-parallel connection.

4. method according to claim 1, is characterized in that, described definite value electric capacity is made up of more than one capacitances in series or in parallel or series-parallel connection.