CN104953260A - Broadband planar helical antenna for detecting partial discharge of electrical equipment and design method thereof - Google Patents

Abstract

The invention discloses a broadband planar helical antenna for detecting the partial discharge of electrical equipment and a design method thereof. The antenna comprises a medium substrate, a grounding plate and an antenna conductor layer, wherein the grounding plate and the antenna conductor layer are respectively laid on both sides of the medium substrate, and the antenna conductor layer comprises a single-arm Archimedes helical conductor and a sine wave-shaped helical conductor. The design method comprises the steps of determining basic parameters, determining initial track parameters of the antenna conductor layer, determining the standing-wave ratio and return loss of the antenna under the initial parameters of initial track calculation of the antenna conductor layer and determining optimum parameters. According to the broadband planar helical antenna and the design method, a mode that the single-arm Archimedes helical conductor and the sine wave-shaped helical conductor are combined is adopted, so that the radiation length is effectively extended, the frequency bandwidth is increased, and good antenna characteristics are guaranteed. The broadband planar helical antenna which is used as a signal detection sensor of the electrical equipment has a plurality of detection bands within a range of 0.3 to 3 GHZ and has the characteristics of good directivity, wide frequency band, convenience in impedance matching, small size and the like.

Description

A kind of broadband planar helical antenna and method for designing thereof detecting local discharge of electrical equipment

Technical field

The present invention relates to a kind of broadband planar helical antenna, especially a kind of broadband planar helical antenna and method for designing thereof detecting local discharge of electrical equipment, belongs to power fault detection technical field.

Background technology

Partial discharge is ubiquity in High-Voltage Insulation.Partial discharges fault is one of modal fault in electric equipment operation process, and Partial Discharge Detection has very important significance.Because high voltage equipment insulation inside exists some bubbles, space, impurity and filth etc., dielectric applied voltage height to a certain extent time, produce partial discharge phenomenon.Partial discharge dispersion occurs in atomic little local space, the penetrability of insulation generally can not be caused to puncture, but can cause dielectric local damage.If partial discharge long-term existence, insulation breakdown and edge flashing can be caused under certain condition.Partial discharge test is carried out to electric equipment, not only can understand the insulation status of equipment, can also Timeliness coverage many about manufacturing and the problem of installation aspect, determine reason and the order of severity thereof of insulation fault.Partial Discharge Detecting Technology, as the nondestructive detection technique of one, can find electrical equipment fault as early as possible, and application widely.

When there is electric discharge in electric equipment, partial discharge pulse width can reach 1-2ns, stimulating frequency can reach the electromagnetic wave of more than 1GHz, hyperfrequency method therefore can be used to carry out Partial Discharge Detection to electric equipment.Hyperfrequency method has higher sensitivity, antijamming capability is strong, and can complete the advantages such as partial discharge identification and fault location, becomes one of emphasis of current research.

Detect partial-discharge ultrahigh-frequency transducer for electric equipment at present and mainly contain microstrip antenna, Archimedes's antenna, fractal antenna, planar equiangular spiral antenna etc.When microstrip antenna is used for local discharge of electrical equipment detection, low frequency signal is detected, for paster area, there is very high requirement, implement and there is very large difficulty.Fractal antenna exists that base time/humorous bandwidth of low order is narrower, adjacent frequency is than the shortcoming such as fixing, the gain of base harmonics is slightly low, polarization purity is low, direction of an electric field is poor, available fractal is few.Archimedian spiral antenna belongs to flat helical antenna, theoretically not by the restriction of working band; But volume is comparatively large, the disc insulator place being not suitable for GIS is detected, and the frequency band relative narrower received, and when detecting local discharge signal, does not have advantage.

Current uhf sensor can not have wider frequency band and less standing-wave ratio, brings undesirable effect to detection local discharge signal.And manufacturing cost is relatively high, cause use not extensive.Therefore develop a kind of antenna that can be used for multiple power equipment Partial Discharge Detection simultaneously with good antenna performance and less volume, have very important significance.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of the broadband planar helical antenna and the method for designing thereof that detect local discharge of electrical equipment.

The technical solution used in the present invention is:

Technical scheme one:

Detect a broadband planar helical antenna for local discharge of electrical equipment, by medium substrate be laid in the ground plate of medium substrate both sides respectively and antenna conductor layer forms; Described antenna conductor layer comprises single armed Archimedian screw wire and sinusoidal wave shape spiral conducting line.

The track of described single armed Archimedian screw wire is determined by its polar equation:

r＝r ₀+a(ψ-ψ ₀),ψ ₀≤ψ≤ψ ₁(1)

Wherein r ₀for the distance between described single armed Archimedian screw wire starting point and initial point, a is the spiral growth rate of described single armed Archimedian screw wire, ψ ₀for the initial angle of described single armed Archimedian screw wire, ψ ₁for the end angle of described single armed Archimedian screw wire, r is the footpath, pole of described single armed Archimedian screw wire track, and ψ is the polar angle of described single armed Archimedian screw wire track;

The track of described sinusoidal wave shape spiral conducting line is determined by its polar equation:

r'＝r ₁+b(ψ'-ψ ₁),,ψ ₁≤ψ'≤ψ ₂(2)

Wherein r ₁=r ₀+ a (ψ ₁-ψ ₀) be the distance between the starting point of described sinusoidal wave shape spiral conducting line and initial point, b is the live width of described sinusoidal wave shape spiral conducting line, ψ ₂for the end angle of described sinusoidal wave shape spiral conducting line, r' is the footpath, pole of described sinusoidal wave shape spiral conducting line track, and ψ ' is the polar angle of described sinusoidal wave shape spiral conducting line track.

Technical scheme two:

Be applied to a method for designing for antenna described in technical scheme one, comprise the following steps:

Step 1: determine basic parameter: described basic parameter comprises: the material of feeding classification, described medium substrate material, thermal endurance class, thickness, described ground plate and antenna conductor layer;

Step 2: the initial track parameter determining described antenna conductor layer: the track of described antenna conductor layer joins the distance r comprised between described single armed Archimedian screw wire starting point and initial point ₀, the spiral growth rate a of described single armed Archimedian screw wire, the initial angle ψ of described single armed Archimedian screw wire ₀with end angle ψ ₁; Determine the distance r between the starting point of described sinusoidal wave shape spiral conducting line and initial point ₁=r ₀+ a (ψ ₁-ψ ₀), the live width b of described sinusoidal wave shape spiral conducting line, the end angle ψ of described sinusoidal wave shape spiral conducting line ₂;

Step 3: the initial track determining described antenna conductor layer: as t=ψ-ψ ₀, t ∈ [0, ψ ₁-ψ ₀], the track of described antenna conductor layer is the track of described single armed Archimedian screw wire, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at})\cos t\\ y=(r_0+\mathrm{at})\sin t\end{array}\right.---\left(3\right)$

Wherein, (x, the y) track that is described single armed Archimedian screw wire is at the coordinate of rectangular coordinate system;

As t=ψ-ψ ₀, t ∈ [ψ ₁-ψ ₀, ψ ₂-ψ ₁], the track of described antenna conductor layer is the track of described sinusoidal wave shape spiral conducting line, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at}+e\sin (40*t))\cos t\\ y=(r_0+\mathrm{at}+e\sin (40*t))\sin t\end{array}\right.---\left(4\right)$

Wherein, e is constant.

Step 4: under calculating initial parameter, the standing-wave ratio VSWR of described antenna and return loss S ₁₁;

Step 5: determine optimal parameter: adjust described initial parameter, between 0.3 ~ 3GHZ, makes the return loss S of described antenna ₁₁absolute value reach maximum, the value of standing-wave ratio VSWR reaches minimum.

The beneficial effect adopting technique scheme to produce is:

1, the present invention adopts the mode that single armed A Ji meter helix combines with sinusoidal wave shape snail line, not only effectively can extend cascade unit, increase frequency bandwidth, and ensure that good antenna performance.

2, the present invention is as the transducer of power equipment input, has multiple detection zone within the scope of 0.3 ~ 3GHZ, features such as having good directionality, bandwidth, be convenient to impedance matching, volume is little.

3, this antenna is when being applied to power equipment Partial Discharge Detection, has good Detection results and economic performance.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.

Fig. 1 is the structural representation of the embodiment of the present invention 1;

Fig. 2 is the flow chart of the embodiment of the present invention 2;

Fig. 3 be the embodiment of the present invention 2 standing-wave ratio figure;

Fig. 4 is the return loss plot of the embodiment of the present invention 2;

Fig. 5 is three-dimensional and the gain schematic diagram of the embodiment of the present invention 2;

Wherein 1, conductor layer 2, medium substrate 3, ground plate.

Embodiment

Embodiment 1:

As shown in Figure 1, a kind of broadband planar helical antenna detecting local discharge of electrical equipment, by medium substrate be laid in the ground plate of medium substrate both sides respectively and antenna conductor layer forms; Described antenna conductor layer comprises single armed Archimedian screw wire and sinusoidal wave shape spiral conducting line.

The track of described single armed Archimedian screw wire is determined by its polar equation:

r＝r ₀+a(ψ-ψ ₀),ψ ₀≤ψ≤ψ ₁(1)

Wherein r ₀for the distance between described single armed Archimedian screw wire starting point and initial point, a is the spiral growth rate of described single armed Archimedian screw wire, ψ ₀for the initial angle of described single armed Archimedian screw wire, ψ ₁for the end angle of described single armed Archimedian screw wire, r is the footpath, pole of described single armed Archimedian screw wire track, and ψ is the polar angle of described single armed Archimedian screw wire track;

The track of described sinusoidal wave shape spiral conducting line is determined by its polar equation:

r'＝r ₁+b(ψ'-ψ ₁),,ψ ₁≤ψ'≤ψ ₂(2)

Wherein r ₁=r ₀+ a (ψ ₁-ψ ₀), be the distance between the starting point of described sinusoidal wave shape spiral conducting line and initial point, b is the live width of described sinusoidal wave shape spiral conducting line, ψ ₂for the end angle of described sinusoidal wave shape spiral conducting line, r' is the footpath, pole of described sinusoidal wave shape spiral conducting line track, and ψ ' is the polar angle of described sinusoidal wave shape spiral conducting line track.

According to helical antenna design principle, helix outer diameter D depends on the wavelength X that lower frequency limit that antenna receives is corresponding _max, generally make its girth C=π D>=1.25 λ _max, according to input impedance, generally get r ₀< λ _min/ 4.Spiral growth rate a is less, and the radius of curvature of helix is less.Under the condition that outer diameter D is identical, helix total length is large, and end effect is little, and band characteristic is better.Helix width is larger, and its input impedance is just lower.In conjunction with the model parameter of above-mentioned computational process determination antenna, thus antenna is designed.Due to r ₀< λ _min/ 4, thus hypothesis initial value r ₀=λ _min/ 4, girth C=π D>=1.25 λ _max, suppose initial C=1.25 λ _max, thus determine the Monobrachial spiral number of turns, namely determine the initial size of ψ 0, ψ 1 and ψ 2, set helix width as 1mm temporarily in conjunction with microminiaturized feature, finally carry out parameter adjustment one by one again according to result of calculation.

In the present embodiment, the material of described medium substrate is glass-epoxy copper-clad plate flame resistant material, and its thermal endurance class is FR-4, and thickness is 2mm, and the material of described ground plate and conductor layer is copper.In order to reduce antenna volume, select coaxial feed mode, input impedance is 50 Ω.The parameter of described antenna is as shown in table 1.

After model parameter is determined, the present invention, according to the medium substrate selected and feeding classification, carries out structural design to Wideband flat helical antenna.Above-mentioned local discharge signal in electric power equipment detects antenna, the apex drive point place of antenna is provided with the through hole running through ground plate, medium substrate and conductor layer, can connects coaxial radio-frequency joint.

Wideband flat helical antenna of the present invention is the transducer of power equipment input, this antenna has multiple detection zone and has fine good directionality within the scope of 0.3 ~ 3GHZ, bandwidth, be convenient to the features such as impedance matching, the volume of other Archimedian spiral antenna is also relatively little relatively simultaneously.This antenna, when being applied to power equipment Partial Discharge Detection, has good Detection results and economic performance.

Technical scheme two:

Be applied to a method for designing for antenna described in technical scheme one, comprise the following steps:

Step 1: determine basic parameter: described basic parameter comprises the material of feeding classification, described medium substrate material, thermal endurance class, thickness, described ground plate and antenna conductor layer; In the present embodiment, the material of the described medium substrate of setting is glass-epoxy copper-clad plate flame resistant material, and its thermal endurance class is FR-4, and thickness is 2mm, and the material of described ground plate and conductor layer is copper;

Step 2: the initial track parameter determining described antenna conductor layer: the track of described antenna conductor layer joins the distance r comprised between described single armed Archimedian screw wire starting point and initial point ₀, the spiral growth rate a of described single armed Archimedian screw wire, the initial angle ψ of described single armed Archimedian screw wire ₀with end angle ψ ₁; Determine the distance r between the starting point of described sinusoidal wave shape spiral conducting line and initial point ₁=r ₀+ a (ψ ₁-ψ ₀), the live width b of described sinusoidal wave shape spiral conducting line, the end angle ψ of described sinusoidal wave shape spiral conducting line ₂; In the present embodiment, the initial track parameter of described antenna conductor layer is as shown in table 1;

Step 3: the initial track determining described antenna conductor layer: as t=ψ-ψ ₀, t ∈ [0, ψ ₁-ψ ₀], the track of described antenna conductor layer is the track of described single armed Archimedian screw wire, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at})\cos t\\ y=(r_0+\mathrm{at})\sin t\end{array}\right.---\left(3\right)$

Wherein, (x, the y) track that is described single armed Archimedian screw wire is at the coordinate of rectangular coordinate system;

As t=ψ-ψ ₀, t ∈ [ψ ₁-ψ ₀, ψ ₂-ψ ₁], the track of described antenna conductor layer is the track of described sinusoidal wave shape spiral conducting line, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at}+e\sin (40*t))\cos t\\ y=(r_0+\mathrm{at}+e\sin (40*t))\sin t\end{array}\right.---\left(4\right)$

Wherein, e is constant.

Step 4: under calculating initial parameter, the standing-wave ratio VSWR of described antenna and return loss S ₁₁;

Step 5: determine optimal parameter: adjust described initial parameter, between 0.3 ~ 3GHZ, makes the return loss S of described antenna ₁₁absolute value reach maximum, the value of standing-wave ratio VSWR reaches minimum.

As shown in Figure 3, described antenna has multiple resonant frequency point within the scope of 300MHz-3GHz, and resonant frequency point place bandwidth is all wider.As shown in Figure 4, there is good Signal reception characteristic within the scope of 300MHz-300MHz.As shown in Figure 5, described antenna has spherical directivity, and can accept the electromagnetic wave signal from all directions, its directivity and gain are all relatively good.Within the scope of 300MHz-3GHz, antenna parameter gets optimal parameter, S ₁₁absolute value be greater than 35dB, standing-wave ratio VSWR is less than 2, can detect local discharge signal preferably.

Table 1

Claims (3)

1. detect a broadband planar helical antenna for local discharge of electrical equipment, it is characterized in that: comprise medium substrate and be laid in ground plate and the antenna conductor layer of medium substrate both sides respectively; Described antenna conductor layer comprises single armed Archimedian screw wire and sinusoidal wave shape spiral conducting line.

2. the broadband planar helical antenna of detection local discharge of electrical equipment according to claim 1, is characterized in that the track of described single armed Archimedian screw wire is determined by its polar equation:

r＝r ₀+a(ψ-ψ ₀),ψ ₀≤ψ≤ψ ₁(1)

Wherein r ₀for the distance between described single armed Archimedian screw wire starting point and initial point, a is the spiral growth rate of described single armed Archimedian screw wire, ψ ₀for the initial angle of described single armed Archimedian screw wire, ψ ₁for the end angle of described single armed Archimedian screw wire, r is the footpath, pole of described single armed Archimedian screw wire track, and ψ is the polar angle of described single armed Archimedian screw wire track;

The track of described sinusoidal wave shape spiral conducting line is determined by its polar equation:

r'＝r ₁+b(ψ'-ψ ₁),,ψ ₁≤ψ'≤ψ ₂(2)

Wherein r ₁=r ₀+ a (ψ ₁-ψ ₀) be the distance between the starting point of described sinusoidal wave shape spiral conducting line and initial point, b is the live width of described sinusoidal wave shape spiral conducting line, ψ ₂for the end angle of described sinusoidal wave shape spiral conducting line, r' is the footpath, pole of described sinusoidal wave shape spiral conducting line track, and ψ ' is the polar angle of described sinusoidal wave shape spiral conducting line track.

3. be applied to a method for designing for the broadband planar helical antenna of detection local discharge of electrical equipment according to claim 1, comprise the following steps:

Step 1: determine basic parameter: described basic parameter comprises: the material of feeding classification, described medium substrate material, thermal endurance class, thickness, described ground plate and antenna conductor layer.

Step 2: the initial track parameter determining described antenna conductor layer: the track of described antenna conductor layer joins the distance r comprised between described single armed Archimedian screw wire starting point and initial point ₀, the spiral growth rate a of described single armed Archimedian screw wire, the initial angle ψ of described single armed Archimedian screw wire ₀with end angle ψ ₁; Determine the distance r between the starting point of described sinusoidal wave shape spiral conducting line and initial point ₁=r ₀+ a (ψ ₁-ψ ₀), the live width b of described sinusoidal wave shape spiral conducting line, the end angle ψ of described sinusoidal wave shape spiral conducting line ₂;

Step 3: the initial track determining described antenna conductor layer: as t=ψ-ψ ₀, t ∈ [0, ψ ₁-ψ ₀], the track of described antenna conductor layer is the track of described single armed Archimedian screw wire, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at})\cos t\\ y=(r_0+\mathrm{at})\sin t\end{array}\right.---\left(3\right)$

Wherein, (x, the y) track that is described single armed Archimedian screw wire is at the coordinate of rectangular coordinate system;

As t=ψ-ψ ₀, t ∈ [ψ ₁-ψ ₀, ψ ₂-ψ ₁], the track of described antenna conductor layer is the track of described sinusoidal wave shape spiral conducting line, is determined by following formula:

$\left\{\begin{array}{c}x=(r_0+\mathrm{at}+e\sin (40*t))\cos t\\ y=(r_0+\mathrm{at}+e\sin (40*t))\sin t\end{array}\right.---\left(4\right)$

Wherein, e is constant.

Step 4: under calculating initial parameter, the standing-wave ratio VSWR of described antenna and return loss S ₁₁;

Step 5: determine optimal parameter: adjust described initial parameter, between 0.3 ~ 3GHZ, makes the return loss S of described antenna ₁₁absolute value reach maximum, the value of standing-wave ratio VSWR reaches minimum.