CN106980050A - A kind of method that utilization surface charge measuring device detects surface charge - Google Patents

Abstract

The present invention discloses a kind of method that utilization surface charge measuring device detects surface charge, and key step includes：Epoxy resin/SiC compound inslation sheet metal specimens of different proportion are made respectively first, it is clean with alcohol wipe, and standing more than the 1h in vacuum environment；Then epoxy resin obtained above/SiC compound inslation sheet metal specimens are lain against to the underface of measurement apparatus pin electrode, the off voltage after pin electrode applies 8KV DC voltages, 3min；Said sample is moved to immediately below surface potential meter measuring probe rapidly below pin electrode, measurement obtains surface potential decay curve, continues 20min；Finally according to surface potential decay curve, the epoxy resin composite insulating material trap level distribution situation for obtaining different SiC mass fractions is calculated.The detection method of the present invention meets the measurement request of surface charge, and the research for nonlinear conductance composite insulating material surface charge properties provides powerful measure.

Description

A kind of method that utilization surface charge measuring device detects surface charge

Technical field

It is more particularly to a kind of to detect table using surface charge measuring device the present invention relates to insulating materials applied technical field The method of surface charge.

Background technology

GIS plays irreplaceable effect in current power system, and the benzvalene form poured by epoxy resin insulate Son is GIS primary insulation part.The annual GIS accidents caused due to disc insulator failure are not within minority, therefore try to subtract Few disc insulator failure is significant.During operation, there is accumulation on disc insulator surface, can cause electric field distortion, So that local electric field strength is greatly enhanced, easily occurs edge flashing failure.

In the research of recent decades, some scholars have found some with non-linear filler (such as carborundum and zinc oxide) Compound its electrical conductivity can change with the change of extra electric field.Numerous studies confirm that nonlinear conductivity is compound exhausted Edge material can play a part of uniform DC electric field, but special for nonlinear conductance composite insulating material surface charge at present The research of property is seldom.

Surface charge measuring device is as shown in figure 1, be divided into high-voltage charging device and potential test device two parts.Choose straight Footpath 1mm, the stainless pin of about 13 μm of tip curvature radius are used as the pin electrode of high-voltage charging device, the height of needle point test coupon It is 5mm, the surface positioned at sample center.Aluminium foil is close to the sample back side, as back electrode and is grounded.High-voltage charging device Effect be by corona discharge to specimen surface inject electric charge.Potentiometric model is Trek347- used in potential test device 3hce, the model of its Kelvin connected probe is 6000b-5c.Its measurement accuracy is ± 3V, and resolution ratio is 3mm.In experiment The height of middle probe distance sample is 3mm.Applied voltage is tested for direct current ± 3kV, ± 4kV, ± 5kV, ± 6kV, ± 7kV, ± 8kV。

The content of the invention

It is an object of the invention to overcome above-mentioned the deficiencies in the prior art, propose one kind using surface charge measuring device inspection The method for surveying surface charge.

The technical scheme is that a kind of method that utilization surface charge measuring device detects surface charge, including it is as follows Step：

(1) epoxy resin/SiC compound inslation sheet metal specimens of different proportion, are made respectively, it is clean with alcohol wipe, and More than 1h is stood in vacuum environment；

(2) epoxy resin of different proportion made from above-mentioned steps (1)/SiC compound inslation sheet metal specimens, are lain against into survey The underface of device pin electrode is measured, the off voltage after pin electrode applies 8KV DC voltages, 3min；

(3) above-mentioned steps (2) epoxy resin/SiC compound inslations sheet metal specimens, are moved into surface rapidly below pin electrode Immediately below potentiometer measurement probe, measurement obtains surface potential decay curve, continues 20min；

(4), according to surface potential decay curve, the epoxy resin for obtaining different SiC mass fractions by formula (1) calculating is answered Close insulating materials trap level distribution situation：

Wherein：ε₀For permittivity of vacuum/Fm^-1, ε₀=8.854187817 × 10-12Fm^-1, ε_rFor relative dielectric Constant, V_sFor surface potential/V of t sample.

The present invention has following beneficial effect relative to prior art：The detection method of the present invention meets the measurement of surface charge It is required that, provide powerful measure, characterization processes of the invention for the research of nonlinear conductance composite insulating material surface charge properties Condition is easy to carry out, and sample is by strict purifying processing, and the degree of accuracy is high and testing result is repeated preferably.

Brief description of the drawings

Fig. 1 is surface charge measurement experimental provision.

Fig. 2 is different epoxy resin compound inslation specimen surface electric-charge-dissipating curves.

Fig. 3 is different epoxy resin compound inslation sample initial sheet current potentials with the change curve of corona voltage.

Fig. 4 is different epoxy resin compound inslation sample trap level distribution maps.

Embodiment

Below by specific embodiments and the drawings, the present invention is further illustrated.Embodiments of the invention are in order to more Those skilled in the art is more fully understood the present invention well, any limitation is not made to the present invention.

The method that a kind of utilization surface charge measuring device of the present invention detects surface charge, comprises the following steps：(1), divide Not Zhi get different proportion epoxy resin/SiC compound inslation sheet metal specimens, it is clean with alcohol wipe,

And more than 1h is stood in vacuum environment；

The preparation method of above-mentioned steps (1) epoxy resin/SiC compound inslation sheet metal specimens is as follows：

A) learn from else's experience the SiC particulate of oversintering, size is 20 ± 1 μm, is fully ground into after powder in 100 ± 10 DEG C of baking oven Middle drying 12 hours or so, to remove the residual moisture in SiC powder；

B) by the SiC powder after above-mentioned steps (1) drying process, pure epoxy resin-base, -0.1MPa pressure are added It is lower to stir and ultrasonically treated 1 hour or so, it is uniformly mixed；

C) by curing agent, (curing agent used is polyamide, and the mass ratio of curing agent and epoxy resin-base is 1:3) Add under mixed liquor, -0.1MPa and stir 10 minutes, it is uniformly mixed；

D) mixed liquor is heated under -0.1MPa pressure to 60-70 DEG C so that mobility reaches that pouring into thickness is most by force 0.05mm clean-polypropylene thin film centers；

E) after cooling down 10 minutes, liquid mobility to be mixed disappears, the polypropylene film of another equal size in covering；

F) by polypropylene film together with cladding content, smooth placement has been preheated to 100 DEG C of thickness and pressed for 0.6mm in advance In piece machine mould, closed die is slowly increased and is depressed into 0.3MPa, 10min；

G) heating power supply of mould is closed, makes its natural cooling, mould is taken apart after 1 hour, polypropylene film of tearing just may be used Obtain epoxy resin/SiC compound inslation thin slices that thickness is 0.1-2mm；

(2) it is 10 that above-mentioned steps (1), are made into ratio:7、10:5、10:1 and 10:0 epoxy resin/SiC compound inslations Sheet metal specimens lie against the underface of measurement apparatus pin electrode, and electricity is disconnected after pin electrode applies 8KV DC voltages, 3min Pressure；

(3), above-mentioned steps (2) sample is moved to immediately below surface potential meter measuring probe rapidly below pin electrode, surveyed Surface potential decay curve (as shown in Figure 2) is measured, continues 20min；As can be seen that epoxy resin/SiC compound inslations surface Electric-charge-dissipating speed is substantially accelerated；

(4), according to surface potential decay curve (as shown in Figure 2), calculated by formula below (1) and obtain different SiC mass The epoxy resin composite insulating material trap level distribution situation of fraction, as shown in Figure 4：

Wherein：ε₀For permittivity of vacuum/Fm^-1, ε₀=8.854187817 × 10^-12F.m^-1, ε_rIt is normal for relative dielectric Number, V_sFor surface potential/V of t sample.It can be seen from figure 4 that with the increase of SiC mass fractions, it is shallow in sample to fall into Trap density constantly increases, and deep trap density is gradually reduced.The increase of shallow trap density and the reduction of deep trap density cause table Surface charge is more easy to occur continuous detrapping-enter sunken process and occur rapid dispersion, so as to suppress the accumulation of surface charge.

Shown in Fig. 3, show that epoxy resin/SiC composite insulating materials can effectively suppress surface electricity when corona voltage is higher The increase of position, and this effect is notable with the increase of SiC additions.

It should be appreciated that embodiment and example discussed herein simply to illustrate that, to those skilled in the art For, it can be improved or be converted, and all these modifications and variations should all belong to the protection of appended claims of the present invention Scope.

Claims (1)

1. a kind of method that utilization surface charge measuring device detects surface charge, it is characterised in that comprise the following steps：

(1) epoxy resin/SiC compound inslation sheet metal specimens of different proportion, are made respectively, it is clean with alcohol wipe, and true More than 1h is stood in Altitude；

(2) epoxy resin of different proportion made from above-mentioned steps (1)/SiC compound inslation sheet metal specimens, are lain against into measurement dress The underface of pin electrode is put, the off voltage after pin electrode applies 8KV DC voltages, 3min；

(3) above-mentioned steps (2) epoxy resin/SiC compound inslations sheet metal specimens, are moved into surface potential rapidly below pin electrode Count immediately below measuring probe, measurement obtains surface potential decay curve, continue 20min；

(4), according to surface potential decay curve, the epoxy resin for obtaining different SiC mass fractions by formula (1) calculating is compound exhausted Edge material trap level distribution situation：

$\frac{N_t\left(E\right)}{E_t}=\frac{4{\mathrm{\ϵ}}_0{\mathrm{\ϵ}}_r}{{\mathrm{eL}}^2{k}^2{T}^{2}ln\left(vt\right)}\left|t\frac{{\mathrm{dV}}_s\left(t\right)}{dt}\right|---\left(1\right)$

Wherein：ε₀For permittivity of vacuum/Fm^-1, ε₀=8.854187817 × 10-12Fm^-1, ε_rFor relative dielectric constant, V_sFor surface potential/V of t sample.