CN110444356B - Lightning protection and anti-icing flashover composite insulator lightning protection section protection gap design method - Google Patents

Abstract

The invention provides a method for designing a lightning protection gap of a lightning protection anti-icing flashover composite insulator, which comprises the following steps of 1-4, step 1: setting a lightning current protection threshold, and step 2: testing the residual voltage of the zinc oxide resistor disc and measuring a lightning protection section volt-ampere characteristic curve, and step 3: protection gap structure design and breakdown voltage test, step 4: and determining a protection gap distance. The method solves the technical problem that the conventional lightning protection and ice flashover prevention composite insulator applied to the power transmission line without the ground wire is lack of a protection device and is easy to damage when the lightning protection section protection gap is subjected to overlarge lightning stroke by scientifically and reasonably designing the lightning protection section protection gap, and the method is simple and easy to implement and has small calculation amount.

Description

A lightning protection and ice flashover protection gap design method for synthetic insulator lightning protection section

technical field

The invention belongs to the technical field of disaster prevention and mitigation of power systems, in particular to a method for designing a protection gap of a lightning protection section of an insulator for lightning protection and ice flashover protection.

Background technique

According to statistics, more than 50% of the tripping accidents in the power system are caused by lightning strikes. With the continuous development of the national economy, the people have put forward higher requirements for the reliability of electricity consumption. Therefore, reducing the lightning trip rate of transmission lines and establishing a sound power grid lightning protection system play an important role in improving the stability of the power system.

As more and more transmission lines cross the alpine mountainous areas, the transmission lines that cancel the ground wire and install the high-current capacity lightning-proof and ice-flash-proof synthetic insulators have been more and more widely used. The lightning protection module can withstand most lightning strikes, but there may also be a phenomenon that the lightning current amplitude is too high, causing the transmission line to trip due to lightning strikes, resulting in lightning protection and ice flashover resulting in insulator damage. Larger lightning current, and improve its lightning protection and anti-ice flash capabilities.

However, in the prior art, in view of the above problems, there is no protection or design method for the lightning protection section of the insulator for lightning protection and ice flashover in a mature system.

SUMMARY OF THE INVENTION

In view of the above situation, the present invention proposes a design method for lightning protection and ice flashover combined with insulator lightning protection section protection gap, so as to solve the problem of the existing lightning protection and ice flashover protection applied to cancel the ground wire transmission line when encountering excessive lightning strikes. Synthetic insulators lack the technical problem that protective devices are prone to damage.

According to one aspect of the present invention, there is provided a method for designing a protection gap for a lightning protection section of an insulator for lightning protection and ice flashover, including the following steps 1 to 4:

Step 1: lightning current protection threshold setting: set the lightning current protection threshold _Im , when the lightning current amplitude exceeds _Im , the protection gap of the lightning protection section is broken down;

Step 2: Residual voltage test of zinc oxide resistor sheet and measurement of volt-ampere characteristic curve of lightning protection section: The volt-ampere characteristic curve of zinc oxide resistor sheet in the high current section is obtained by the inrush current acting on the zinc oxide resistor sheet, and different impulses are obtained. Residual voltage of lightning protection section under the action of current;

Step 3: Protection gap structure design and breakdown voltage test: The rod-rod electrode is used as the protection gap structure, and the pulse voltage is output through the impulse voltage generator, and the breakdown voltage test is carried out to measure the rod-rod electrode impact under different gap distances. Flashover voltage, and get the relationship curve of positive and negative polarity impact flashover voltage with gap distance;

Step 4: Determination of the protection gap distance: According to the lightning current protection threshold _Im in step 1 and the volt-ampere characteristic curve of the lightning protection section in step 2, the action residual voltage U _m at both ends of the lightning protection section is obtained, and according to the action residual voltage U _m and the relationship between the positive and negative polarity impulse flashover voltage in step 3 and the gap distance, calculate the protective gap distance d _m .

Further, the lightning strike current protection threshold _Im <150kA of the step 1.

Further, the step 2 specifically includes: generating an impulse current with a waveform of 4/10 μs pulse type by an impulse current generator, which acts on the zinc oxide resistance sheet used in the lightning protection section, and the impulse current amplitude is 50-150kA, and each impulse current is 50-150kA. 10kA test a point, each test uses a new resistance piece, until the zinc oxide resistance piece is damaged, the volt-ampere characteristic curve of the zinc oxide resistance piece is measured and measured, and the volt-ampere characteristic curve of a single piece of zinc oxide resistance piece is multiplied by the resistance piece. The number is equal to the volt-ampere characteristic curve of the entire lightning protection section, and the volt-ampere characteristic curve is a piecewise linear function:

Among them, U ₁ represents the residual voltage, I represents the current value, a ₁ , b ₁ , a ₂ , and b ₂ are the linear fitting constants obtained during linear fitting, respectively, and I ₀ is the nonlinear segment in the volt-ampere characteristic curve. critical value of the current segment.

Further, the step 3 specifically includes: when designing the protection gap structure, in order to achieve high current capability and lightning protection and anti-icing flashover functions, and considering the small polar effect of the rod-bar gap, the protection gap electrode structure is selected as the rod-rod gap. structure, apply a 2.6/50μs pulsed impulse voltage to the rod protection gap, and obtain the breakdown voltage variation curve with the gap distance,

The calculation formula of positive and negative polarity impulse flashover voltage with gap distance is obtained by fitting:

Among them, U ₃ and U ₄ represent the positive and negative breakdown voltages of the protective gap, respectively, d represents the distance of the protective gap, and a ₃ , b ₃ , a ₄ , and b ₄ are constants obtained by fitting, respectively.

Further, the relationship curve of the positive and negative polarity impulse flashover voltage with the gap distance in the steps 3 and 4 is specifically selected as the relationship curve of the negative polarity impulse flashover voltage with the gap distance.

In another aspect, the present invention also discloses a lightning protection and ice flashover protection gap design device for insulator lightning protection section, comprising:

at least one processor; and

at least one memory communicatively coupled to the processor, wherein:

The memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the lightning protection section protection gap design method described in any one of the above.

In another aspect, the present invention also discloses a non-transitory computer-readable storage medium, the non-transitory computer-readable storage medium stores computer instructions, the computer instructions cause the computer to execute any one of the above The lightning protection section protection gap design method.

Compared with the prior art, the beneficial effects of the present invention are:

1. The lightning protection section protection gap design method of the present invention can effectively divert excessive lightning current and prevent lightning protection and ice flashover from being easily damaged by lightning current.

2. The lightning protection section protection gap design method of the present invention can also design insulators with different specifications and requirements in batches, and the design method is simple and effective, and is suitable for calculation by computer operation.

Description of drawings

Fig. 1 is the structure diagram of lightning protection and anti-icing flashover insulator and protection gap in the present invention;

Fig. 2 is the flow chart of the protection gap design method of the lightning protection section of the insulator lightning protection section of the lightning protection and ice flashover in the present invention;

FIG. 3 is a graph showing the corresponding relationship between the variables of the lightning current, the voltage at both ends of the lightning protection section and the distance of the protection gap according to the present invention.

Description of reference numbers:

1. Lightning protection and ice flashover are combined into insulator lightning protection section, 2. Lightning protection and ice flashover are combined into insulator insulation section, 3. Voltage equalizing ring at both ends of insulation section, 4. Protection gap at both ends of lightning protection section.

Detailed ways

The present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments, and also describe the technical problems and beneficial effects solved by the technical solutions of the present invention. It should be pointed out that the described embodiments are only intended to facilitate the understanding of the understand without any restriction on it.

As shown in Figure 1, it is a diagram showing the structure of the lightning protection and ice flashover insulator and the protection gap, as a conventional lightning protection and ice flashover insulator, wherein the reference numeral 1 represents the lightning protection section of the lightning protection and ice flashover insulator, 2 means lightning protection and ice flashover combined into insulator insulation section, 3 means voltage equalizing ring at both ends of insulation section, 4 means protection gap at both ends of lightning protection section. The two ends of the protection gap 4 at both ends of the lightning protection section are respectively connected with the grounding end of the lightning protection and ice protection insulator and the voltage equalizing ring 3 of the insulation section. When lightning acts on the transmission line, the voltage equalizing ring 3 of the insulation section breaks down first, and the lightning enters the ground along the arc at both ends of the insulation section and the zinc oxide resistance sheet in the lightning protection section. When the lightning current is too large, the residual voltage of the lightning protection section leads to the breakdown of the protection gap, and the lightning current enters the ground plane along the gap arc of the protection gap, thereby protecting the zinc oxide resistor sheet.

As shown in the flow chart of the lightning protection and ice flashover protection gap design method of the insulator lightning protection section in FIG. 2, the lightning protection and ice flashover protection gap design method of the insulator lightning protection section of the present invention is used to design the lightning protection section parallel protection gap , When lightning protection and ice flashover combined with insulator lightning protection section is struck by lightning with high amplitude, the lightning will break down along the protection gap and will not flow through the zinc oxide resistor, which can prevent the lightning protection section from being damaged due to excessive lightning current amplitude. , has the characteristics of simple structure and high reliability, which specifically includes the following steps:

Step 1: Lightning current protection threshold setting: Set the lightning current protection threshold I _m (I _m <150kA), when the lightning current amplitude exceeds I _m , the protection gap breaks down;

Step 2: Residual voltage test of zinc oxide resistor sheet and measurement of volt-ampere characteristic curve of lightning protection section: The surge current is generated by the surge current generator, which acts on the zinc oxide resistor sheet, and the volt-ampere of the zinc oxide resistor sheet in the high current section is obtained by testing. characteristic curve to obtain the residual voltage of the lightning protection section under the action of different impulse currents;

The step 2 specifically includes: generating an impulse current with a waveform of 4/10 μs pulsed by an impulse current generator, which acts on the zinc oxide resistance sheet used in the lightning protection section, the impulse current amplitude is 50-150kA, and one test is performed every 10kA. Point, use a new resistance piece for each test until the zinc oxide resistance piece is damaged, and measure the volt-ampere characteristic curve of the zinc oxide resistance piece. The volt-ampere characteristic curve of the lightning protection section, the volt-ampere characteristic curve is a piecewise linear function:

In the above formula, U ₁ represents the residual voltage, I represents the current value, a ₁ , b ₁ , a ₂ , b ₂ are the linear fitting constants obtained during linear fitting, respectively, and I ₀ is the nonlinear segment in the volt-ampere characteristic curve. and the critical value of the high current segment (see the intersection of the two straight lines on the left in Figure 3).

Step 3: Design of protective gap structure and breakdown voltage test: Considering the small polarity effect of rod-rod electrodes, rod-rod electrodes are used as protective gap structure, and pulse voltage is output through impulse voltage generator to conduct breakdown voltage test , measured the rod-rod electrode impulse flashover voltage under different gap distances, and obtained the relationship between the positive and negative polarity impulse flashover voltage with the gap distance.

The step 3 specifically includes: when designing the protection gap structure, in order to achieve high current capacity and lightning protection and anti-icing flashover functions, and considering the small polar effect of the rod-rod gap, the protection gap electrode structure is selected as the rod-rod gap structure. A pulsed impulse voltage of 2.6/50μs is applied to the rod-rod protection gap, and the change curve of breakdown voltage with gap distance is obtained.

The calculation formula of positive and negative polarity impulse flashover voltage with gap distance is obtained by fitting:

In the above formula, U ₃ and U ₄ represent the positive and negative breakdown voltages of the protective gap, respectively, d represents the distance of the protective gap, and a ₃ , b ₃ , a ₄ , and b ₄ are constants obtained by fitting, respectively.

Step 4: Determination of the protection gap distance: According to the lightning current protection threshold I _m and the volt-ampere characteristic curve of the lightning protection section in step 2, the action residual voltage U _m at both ends of the lightning protection section is obtained, and according to the action residual voltage U _m and in step 3 The relationship curve of the positive and negative polarity impulse flashover voltage with the gap distance, the protective gap distance d _m is obtained by calculation.

It is worth mentioning that the method of the present invention is particularly suitable to be implemented by computer software, so the above-mentioned lightning protection and ice protection flashover protection gap design method for the insulator lightning protection section can use a non-transitory computer-readable storage medium with computer instructions or A computer including a processor is implemented.

Figure 3 shows the volt-ampere characteristic curve of the zinc oxide resistor sheet in the impact section and the relationship between the gap distance and the lightning voltage amplitude. First, according to the lightning current action amplitude _Im , and the volt-ampere characteristic curve of the lightning protection section in step 2 (ie, the coordinate curve on the left in Fig. 3 ), the residual voltage U _m of the zinc oxide resistance sheet action is obtained by sorting out, according to the zinc oxide resistance The chip action residual voltage U _m , and the corresponding protection is calculated according to the action residual voltage U _m and the relationship curve of the positive and negative polarity impulse flashover voltage with the gap distance in step 3 (that is, the coordinate curve on the right in Figure 3). For the distance d _m , due to the fact that the negative polarity lightning is the majority in nature, the setting calculation is performed preferentially according to the negative polarity lightning (corresponding to the linear curve of the voltage U ₄ ). It is worth mentioning that, in order to reduce the amount of calculation, the linear fitting calculation of the relationship curve is carried out, that is, the volt-ampere characteristic curve of the lightning protection section in step 2 and the positive and negative polarity impulse flashover voltage in step 3 with the gap distance. The curves are all linear curves.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be used for The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (5)

1. A method for designing a lightning protection gap of a lightning protection anti-icing flashover composite insulator is characterized by comprising the following steps

Step 1: setting a lightning current protection threshold value: setting lightning current protection threshold I_mWhen the amplitude of the lightning current exceeds I_mWhen the lightning protection section is in a lightning protection state, the protection gap of the lightning protection section is broken down;

step 2: the method comprises the following steps of (1) zinc oxide resistance card residual voltage test and lightning protection section volt-ampere characteristic curve measurement: the surge current acts on the zinc oxide resistance card, a volt-ampere characteristic curve of the zinc oxide resistance card in a large current section is obtained through testing, and the lightning protection section residual voltage under the action of different surge currents is obtained; the step 2 specifically comprises: the surge current generator generates surge current with the waveform of 4/10 mu s pulse type, the surge current acts on a zinc oxide resistance card adopted in a lightning protection section, the amplitude of the surge current is 50-150kA, each 10kA point is tested, a brand new resistance card is adopted in each test until the zinc oxide resistance card is damaged, the volt-ampere characteristic curve of the zinc oxide resistance card is obtained by measurement, the volt-ampere characteristic curve of a single zinc oxide resistance card is multiplied by the volt-ampere characteristic curves of the whole lightning protection section, and the volt-ampere characteristic curve is a piecewise linear function:

wherein, U₁Denotes residual voltage, I denotes current value, a₁，b₁，a₂，b₂Linear fitting constants, I, obtained when fitting respectively to a line₀The critical value of a nonlinear section and a large current section in the volt-ampere characteristic curve;

and step 3: protection gap structure design and breakdown voltage test: adopting a rod-rod electrode as a protective gap structure, outputting pulse voltage through an impulse voltage generator, carrying out a breakdown voltage test, measuring to obtain rod-rod electrode impulse flashover voltages under different gap distances, and obtaining a relation curve of positive and negative polarity impulse flashover voltages along with the gap distances; the step 3 specifically includes: when the protective gap structure is designed, in order to realize high-current capacity and lightning protection and anti-icing flashover functions and considering that the polarity effect of the rod-rod gap is small, the protective gap electrode structure is selected as a rod-rod gap structure, pulse type impact voltage of 2.6/50 mu s is applied to the rod-rod protective gap, and a curve of breakdown voltage changing along with the gap distance is obtained;

fitting to obtain a calculation formula of positive and negative polarity impact flashover voltage along with the gap distance:

wherein, U₃And U₄Respectively representing the positive breakdown of the guard gapVoltage and breakdown voltage of negative polarity, d represents the protection gap distance, a₃，b₃，a₄，b₄Respectively are constants obtained by fitting;

and 4, step 4: and (3) determining a protection gap distance: according to the lightning stroke current protection threshold I in the step 1_mAnd step 2, obtaining the action residual voltage U at the two ends of the lightning protection section by the volt-ampere characteristic curve of the lightning protection section_mAnd according to the residual action voltage U_mAnd 3, calculating a relation curve of the positive and negative polarity impact flashover voltage along with the gap distance to obtain a protection gap distance d_m。

2. The lightning protection segment protection gap design method of claim 1, wherein the lightning strike current protection threshold I of step 1_m<150kA。

3. The method for designing the lightning protection section protection gap according to claim 1, wherein the relationship curve of the positive and negative polarity impulse flashover voltages with the gap distance in the steps 3 and 4 is specifically selected as the relationship curve of the negative polarity impulse flashover voltages with the gap distance.

4. The utility model provides a lightning protection anti-icing sudden strain of a muscle synthetic insulator lightning protection section protection clearance design device which characterized in that includes:

at least one processor; and

at least one memory communicatively coupled to the processor, wherein:

the memory stores program instructions executable by the processor, the processor invoking the program instructions to enable performance of the lightning protection segment protection gap design method of any one of claims 1 to 3.

5. A non-transitory computer-readable storage medium storing computer instructions that cause a computer to perform the lightning protection segment protection gap design method of any one of claims 1 to 3.

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