CN105467240A - Lightning arrester online parameter monitoring correction method eliminating interference from external environment factors - Google Patents

Abstract

The invention discloses a lightning arrester online monitoring parameter correction method that eliminates the interference of external environmental factors, and uses the phase deviation index of the operating field and based on the resistive current operating field resistive current index at the same standard temperature t _nor and standard humidity h _nor Correct the measured data of the arrester, where t represents temperature, h represents humidity, is the standard phase, I _x-nor is the standard full current, and the same standard temperature t _nor and standard humidity h _nor correspond to the only standard phase and standard full current _Inor . The invention realizes the visualization and indexing of abstract problems, solves the problem of early warning and monitoring under the abnormal operation state of the lightning arrester, and provides intuitive and scientific measurement and reference indexes for users.

Description

Correction method of lightning arrester online monitoring parameters to eliminate interference from external environmental factors

technical field

The invention relates to the field of metal oxide lightning arrester monitoring, and more specifically relates to an online monitoring parameter correction method for lightning arresters that eliminates interference from external environmental factors.

Background technique

Through the research, it is found that the change of the operating state of the arrester is reflected in the change of the two internal parameters of the full current and the resistive current flowing through the arrester, that is, the full current and resistive current of the arrester can be used to characterize the actual operating state of the arrester, and realize Monitoring and early warning when the arrester is running. However, the full current and resistive current of the arrester are also affected by external environmental factors (mainly temperature and humidity), and the influence of external environmental factors on the internal parameters of the arrester must be eliminated, so as to achieve accurate measurement of arrester parameters and online operation status of the arrester. Accurate monitoring.

Contents of the invention

The present invention overcomes the deficiencies of the prior art, and provides an online monitoring parameter correction method for lightning arresters that eliminates interference from external environmental factors. Parameter I _x , current and voltage phase difference To characterize the change, the operating field phase error index _e and the operating field resistive current index I _r are established to quantitatively measure the change of the operating state of the arrester, which realizes the visualization and indexing of abstract problems and solves the abnormal operating state of the arrester. Early warning and monitoring issues provide users with intuitive and scientific measurement and reference indicators.

In order to solve the above technical problems, considering that the actual internal parameters of the arrester are affected by temperature and humidity at the same time, it is necessary to first study the influence of temperature and humidity on the internal parameters of the arrester, and then establish a suitable three-dimensional spatial model and related indicators to quantify Measure the change of the operating state of the arrester, and realize the monitoring and early warning of the arrester during operation.

The present invention adopts following technical scheme:

The lightning arrester online monitoring parameter correction method that eliminates the interference of external environmental factors to operate the field phase deviation index: And based on the resistive current operating field resistive current index I _r at the same standard temperature t _nor and standard humidity h _nor : Correct the measured data of the arrester, where t represents temperature, h represents humidity, is the standard phase, I _x-nor is the standard full current, and the same standard temperature t _nor and standard humidity h _nor correspond to the only standard phase and standard full current _Inor .

Modeling of arrester internal parameters full current _Ix and resistive current _Ir : from the perspective of energy, the state model of the arrester during operation is represented as the arrester operating field Fa, through which internal temperature t ₁ , humidity h, current Voltage phase difference The change mapping of the four parameters of the full current I _x characterizes the state of the operating field Fa of the arrester, namely: Then the full current I _x and phase difference in the internal parameters of the arrester The three-dimensional least squares surface fitting model for the external variables temperature t ₁ and humidity h are respectively carried out as follows: The actual spatial sampling point full current I _x and the phase difference Using the curved surface as a reference to carry out the calculation under standard temperature and standard humidity, and obtain the full current I' _x and phase difference under the reference standard

The calculation method of the phase deviation index of the operating field is: use the surface fitting mathematical model expression of the arrester parameters:

F _a (h,t)＝p ₀₀ +p ₁₀ t+p ₀₁ h+p ₂₀ t ² +p ₁₁ t h; where t represents temperature, h represents humidity, p00～p11 are the parameters to be fitted, and the fitting The fitting residuals of the phase difference surface and the full current surface are respectively:

In the formula, i=1, 2, ..., N, N is the data sample length, and then the same standard temperature t _nor and standard humidity h _nor correspond to the only standard phase and standard full current _Inor : The standard phase fitted by the above formula is the phase value after eliminating the temperature and humidity interference. There are maximum and minimum values in its distribution, and the phase deviation index of the operating field is:

Compared with prior art, the beneficial effect of the present invention is:

According to the internal operation principle of the arrester and the changes in the electric field, electromagnetic field and temperature field, the operating state of the arrester passes the state quantity full current parameter I _x , current and voltage phase difference To characterize the change, the operating field phase error index _e and the operating field resistive current index I _r are established to quantitatively measure the change of the operating state of the arrester, which realizes the visualization and indexing of abstract problems and solves the abnormal operating state of the arrester. Early warning and monitoring issues provide users with intuitive and scientific measurement and reference indicators.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Figure 1 Phase difference and the distribution curve of temperature t ₀ ;

Figure 2 Generated new phase difference and the distribution curve of temperature t ₀ ;

The schematic diagram of temperature _t1 after compensation in Fig. 3;

Figure 4 is the relationship diagram of full current, phase difference, temperature and humidity;

Figure 5 is a comparison chart of measured data correction.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings. Embodiments of the present invention include, but are not limited to, the following examples.

Example 1

Analyze the arrester model from the energy point of view. It is assumed that the state model of the arrester during operation is represented by the operating field F _a of the arrester, which is composed of a series of electric field F _e , magnetic field F _g , temperature field F _t , and humidity field F _h According to the representation of a certain mathematical relationship s(F _e , F _g , F _t , F _h ), that is:

F _a =s(F _e ,F _g ,F _t ,F _h )(3-21)

Through research, it is found that the electric field _Fe , temperature field _Ft , and humidity field _Fh are important elements to characterize the state of the operating field _Fa , while the full current _Ix , current-voltage phase difference _iu are important factors to characterize the electric field _Fe , and the temperature t is an important factor to characterize the temperature field F _t , and humidity h is an important factor to characterize the humidity field F _h . Therefore, the arrester internal temperature t ₁ , humidity h, current and voltage phase difference The change of the four parameters of the full current I _x is used to map and characterize the state of the operating field F _a of the arrester, namely:

The space field distribution law of the internal temperature t ₁ of the arrester is as follows: the closer to the center of the arrester, the greater the temperature value, the greater the probability of its occurrence, and the more scattered points; as the distance from the central point increases, the temperature presents Attenuation trend, the less the corresponding scatter value.

The internal parameters of the arrester in formula (3-22) I _x , Both are affected by external factors such as temperature t and humidity h. The study found that it is difficult to accurately measure the internal operating temperature t ₁ of the arrester in practice, but the temperature t ₀ on the surface of the arrester can be measured, and its changing trend is the same as t ₁ , but there is a certain delay before the two. Therefore, for the full current I _x and the phase difference in the internal parameters of the arrester The three-dimensional least squares surface fitting model for the external variables temperature t ₁ and humidity h are respectively carried out as follows:

For fitting the resulting mathematical model F _Ix , its physical meaning means that there is a unique phase surface under the space field composed of different temperature and humidity and the full current F _Ix make the sum of the squares of the distances from each discrete space phase point and full current point to the respective surface the smallest, that is, the generated surface is closest to the real value.

For the same standard temperature t _nor and h _nor under the standard humidity, there is a unique standard phase and the standard full current _Inor , the actual spatial sampling point full current I _x and the phase difference Using the curved surface as a reference to carry out the calculation under standard temperature and standard humidity, and obtain the full current I' _x and phase difference under the reference standard The calculation model for further obtaining the parameter I _r of the resistive current component is as follows:

Example 2

Operating field phase deviation index and operating field resistive current

According to the above analysis, the purpose is to obtain the phase difference parameter in formula (3-23) The relationship model between the full current I _x and the internal operating temperature t ₁ of the arrester and the humidity h, and the temperature t ₁ can only be characterized by the surface temperature t ₀ , and finally the phase deviation index _e of the operating humidity field is obtained.

1) The internal temperature t ₁ is simulated from the external temperature t ₀

According to the spatial distribution law of the temperature field influence factor _t1 of the arrester, both _t1 and _t0 should reflect the state of the actual arrester operating field F _a , and _t0 can be regarded as the temperature field influence factor _t1 in different positions in space state, the model is simplified according to the law of energy transfer in the humidity field, and t ₀ is regarded as the state quantity after the delay of t ₁ , that is, the temperature t ₁ actually simulated by the known temperature t ₀ needs to have the same variation trend as t ₀ , At the same time, it has certain advanced characteristics relative to t ₀ .

On the other hand, the state change trend of the arrester is: the internal temperature t ₁ rises, the current and voltage phase difference in the circuit The value becomes smaller; the internal temperature t ₁ decreases, and the current and voltage phase difference in the circuit The value becomes larger, and the two have an equal trend of change. Set the phase difference parameter and temperature _t1 both obtain the extreme point at the same time, the temperature difference of _t0 delaying _t1 is Δt, and the delay factor is , which corresponds to the discrete data sampled, its expression is:

Δt(i)=t ₁ (i)-t ₀ (i), i=0,1,...,N-1(3-25)

t ₁ (i)=t ₀ (i-β)(3-26)

In the formula, N represents the total number of sampling points. Then the temperature difference Δt should maintain the same variation trend as t ₁ (or t ₀ ).

Taking the actual engineering sampling signal as the analysis sample, theoretical analysis and derivation are carried out on it. The data distribution curves of the sampled current, voltage phase difference _iu and temperature _t0 are shown in Figure 1. In order to make It is consistent with the change trend of t ₀ , and a transformation is performed on , and the phase difference after the change is set as Then the corresponding relational expression:

and must satisfy the following constraints:

Figure 1 New phase difference generated after transformation The distribution diagram of is shown in Figure 2. From Figure 2, it can be seen that the temperature t ₀ lags behind the new phase difference For a certain period of time, set the delay factor as β, which is approximately equal to the delay factor of t ₀ relative to t ₁ in formula (3-26). In order to obtain β and simulate the generated temperature t ₁ , according to the new phase difference and t ₀ curve extreme point distribution law, in order to make the extreme point appear at the same time, the new phase difference As a reference, the average value t _0avr of temperature t ₀ is used as the decomposition line, and the hysteresis factor of the maximum value point greater than t _0avr is β ₁ , and the hysteresis factor of the minimum value point smaller than t _0avr is β ₂ , then the newly generated simulation The temperature _t1 is:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; r</span>}}\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; r</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 29</span>}<span\; class="notranslate">\; )</span>$

In the formula $t_{0avt}=\frac{1}{N}\underset{\mathrm{no}=0}{\overset{N-1}{\&Sigma;}}{t}_0\left(\mathrm{no}\right),\mathrm{no}=0,1,\mathrm{...},N-1.$

Similarly, formula (3-29) needs to satisfy the constraints:

Equation (3-29) is the newly generated internal temperature t ₁ of the arrester, its changing trend is consistent with the temperature t ₀ , and the time scale remains the same as Consistent, the data gaps that may appear at the head end can be supplemented according to the changing rules of nearby points. The schematic diagram of the temperature t ₁ curve generated by Fig. 2 is shown in Fig. 3 .

2) The fitting relationship between the internal parameters of the arrester and the internal temperature t ₁ and humidity h

In order to better fit the internal parameters of the arrester (full current I _x and phase difference ) and the simulated internal temperature t ₁ , humidity h relationship curve, firstly, the parameter data of the arrester caused by the abnormal operation state of the equipment itself must be removed, and at the same time, the parameter data of the arrester calculated when the fundamental frequency of the current and voltage are not equal shall be replaced by interpolation , and finally constitute the full current I _x of equal length to eliminate interference, and the phase difference The obtained full current I _x , phase difference The relationship diagram of temperature _t1 and humidity h is shown in Fig. 4.

According to the formula (3-23), the phase difference-temperature-humidity, full current-temperature-humidity are respectively fitted with the least squares surface to obtain the fitted surface F _Ix .

The study found that the mathematical model expression for surface fitting suitable for arrester parameters is:

F _a (h,t)＝p ₀₀ +p ₁₀ t+p ₀₁ h+p ₂₀ t ² +p ₁₁ t·h(3-31)

In the formula, t represents temperature, h represents humidity, and p ₀₀ to p ₁₁ are parameters to be fitted.

The fitted phase difference surface For the full current surface F _Ix (h,t), the fitting residuals are:

In the formula, i=1, 2, ..., N, N is the data sample length.

Then based on the same standard temperature t _nor and standard humidity h _nor corresponding to the only standard phase and standard full current _Inor :

4) Operation field phase deviation index

The standard phase fitted by equation (3-33) That is, the phase value after eliminating the temperature and humidity interference, its distribution has a maximum value and a minimum value, and the phase deviation index of the operating field is:

Operating Field Phase Deviation Index It is an important characterization of the operating state of the arrester.

5) Operating field resistive current index I _r

According to formula (3-33) and formula (3-24), the resistive current based on the same standard temperature t _nor and standard humidity h _nor is

The resistive component (ie, resistive current) in the leakage current of the arrester resistor reflects the aging and moisture of the arrester resistor, which can monitor the operation status of the arrester. If the operating state of the arrester remains unchanged, the resistive current index I _r of the operating field should maintain a relatively stable level, and the change of the arrester state will inevitably lead to changes in the resistive current parameters.

To sum up, the operating state of the arrester is determined by the state quantity, the full current parameter I _x , the current and voltage phase difference To characterize the change, the operating field phase error index was established The field resistive current index I _r is used to quantitatively measure the change of the operating state of the arrester, and the abstract problem is visualized and indexed.

Example 2

Correction results of measured data

For the 10-day arrester actual measurement data, the correction measurement of the above method is carried out, and the original data is compared with the original data. The results obtained are shown in Table 1 and Figure 5 below:

Table 3-3 Comparison of correction and processing results of measured data

It can be seen from Table 3-3 and Figure 5 that due to the influence of external environmental factors (temperature, humidity) on the original arrester data, the variation range (span) of the full current, phase difference and resistive current is very large, while after correction The variation range of the arrester data is greatly reduced and tends to be constant. The measured data verifies that this method can reduce the influence of environmental factors on the parameters of the arrester, so that the monitoring of the operation status of the arrester can be realized.

The foregoing is an embodiment of the present invention. The present invention is not limited to the above embodiments, and anyone should know that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same as or similar to the present invention, all fall within the protection scope of the present invention.

Claims (3)

1. eliminate the lightning arrester on-line monitoring parameter correction method of external environmental factor interference, it is characterized in that, to run field phase Deviation Indices with based on same standard temperature t _norwith standard humidity h _norunder current in resistance property run field current in resistance property index I _r: revise lightning arrester measured data, in formula, t represents temperature, h represents humidity, for normalized phase, I _x-norfor standard total current, same standard temperature t _norwith standard humidity h _norlower all corresponding unique normalized phase with standard total current I _nor.

2. modification method according to claim 1, is characterized in that: thunder device inner parameter total current I _xwith current in resistance property I _rmodeling: from energy point of view modeling, lightning arrester state model is operationally characterized by lightning arrester and runs field Fa, with by lightning arrester internal temperature t ₁, humidity h, current/voltage phase differential total current I _xthe change of four parameters maps and characterizes the state that lightning arrester runs field Fa, that is: again to the total current I in lightning arrester inner parameter _xand phase differential carry out respectively about extraneous delta temperature t ₁, humidity h three-dimensional least-squres camber fitting model as follows:

By real space sampled point total current I _xand phase differential taking curved surface as the reduction with reference to carrying out under standard temperature and standard humidity, obtaining the total current I ' under reference standard _xand phase differential

3. modification method according to claim 1, is characterized in that: the computing method running field phase Deviation Indices are: the surface fitting mathematical model expression formula by lightning arrester parameter:

F _a(h, t)=p ₀₀+ p ₁₀t+p ₀₁h+p ₂₀t ²+ p ₁₁th; In formula, t represents temperature, h represents humidity, and p00 ~ p11 is for treating fitting parameter, and the phase differential curved surface that matching obtains, the regression criterion of total current curved surface are respectively:

i=1 in formula, 2 ..., N, N be data sample length,

Obtain same standard temperature t again _norwith standard humidity h _norlower all corresponding unique normalized phase with standard total current I _nor: being the phase value after eliminating temperature, humidity interference with above-mentioned formula fitting normalized phase out, there is maximal value and minimum value in its distribution, runs field phase Deviation Indices and is: