CN113258492B

CN113258492B - Ultra-fast transient overvoltage suppression structure and gas insulated substation integrated equipment

Info

Publication number: CN113258492B
Application number: CN202110764645.2A
Authority: CN
Inventors: 陈庆; 李红斌; 韩林汕
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2021-07-07
Filing date: 2021-07-07
Publication date: 2021-10-01
Anticipated expiration: 2041-07-07
Also published as: CN113258492A

Abstract

The invention relates to an ultra-fast transient overvoltage suppression structure and gas insulated substation integrated equipment, wherein the suppression structure is coated on the outer side of a primary bus of a gas insulated substation or arranged on the inner side of a shell of the gas insulated substation; the suppression structure includes an insulating layer, a damping resistance layer, and a semiconductor layer. The invention starts from a primary equipment structure, increases an insulating layer, a damping resistance layer and a semiconductor layer according to the electromagnetic wave dispersion principle on the premise of not changing the structures of a GIS sleeve, a shell and a pipeline guide rod, realizes the separation of a power frequency signal and a high-frequency VFTO signal, and obviously increases the impedance of the high-frequency signal, thereby achieving the purpose of inhibiting the VFTO and realizing the protection of primary equipment and secondary equipment. The technical scheme provided by the invention has a simple structure, is suitable for improving the structure of the bus and the shell of the existing GIS integrated equipment, and can guide the design of the bus and the shell of the novel GIS integrated equipment.

Description

Ultra-fast transient overvoltage suppression structure and gas insulated substation integrated equipment

Technical Field

The invention relates to the field of power equipment operation protection, in particular to a VFTO restraining structure for GIS integrated equipment.

Background

In a Gas Insulated Substation (GIS), a moving contact of an isolating switch in the switching-on and switching-off process is slow in moving speed, so that multiple reignition or pre-breakdown phenomena of an SF6 Gas gap between fractures of the isolating switch can be caused, a steep Voltage traveling wave can be generated in each breakdown, multiple refraction, reflection and superposition are generated at a discontinuous point of wave impedance in the GIS, and finally Very Fast Transient Overvoltage (VFTO) is formed. VFTO is different from the conventional operation overvoltage of a common air insulated substation, and has mainly four characteristics: firstly, the rising time of the waveform is extremely short, and is usually within the range of 5-20 ns; secondly, the frequency spectrum range is wide, and frequency components from direct current to hundreds of MHz are included; thirdly, the amplitude is high and can reach 2p.u. -3 p.u.; fourthly, the duration is very short, and the very fast transient process generated by a single breakdown can be as low as tens of times.

VFTO can harm the insulation of primary equipment of a transformer substation, particularly winding equipment, can cause the insulation accident of a GIS primary bus to a shell, and can threaten the insulation of the winding equipment connected with the GIS. Along with the improvement of the voltage grade of the GIS, the insulation margin of primary equipment is obviously reduced, and the safety operation of the power system is more harmfully affected by VFTO. In addition, VFTO can also produce harm to the safe operation of secondary equipment in the transformer substation, because the requirement of practicality and economic nature in the smart power grids construction, secondary weak current equipment is often placed near primary high-voltage equipment, and the overvoltage that GIS switching operation produced can direct action in the weak current return circuit, threatens secondary weak current equipment's insulation, leads to secondary equipment to break down.

In the prior art, VFTO is usually inhibited by installing a switching-on/off resistor, installing a high-frequency magnetic ring, installing a metal oxide arrester and the like. These measures all have significant inhibitory effects on VFTO, but are also deficient. Installing the on-off resistance additional at GIS isolator can lead to isolator structure complicacy, increases isolator's manufacturing and use cost, simultaneously, installs the on-off resistance and makes operating mechanism more complicated, increases the probability that takes place mechanical failure. The magnetic material of the high-frequency magnetic ring has high brittleness, is easy to break and drop slag, and is easy to damage the high-frequency magnetic ring if impact or vibration is encountered in the transportation, installation, maintenance and GIS operation processes, so that the function effect of inhibiting VFTO is reduced. The metal oxide arrester needs to be installed at a proper position of the GIS, and the suppression effect of the arrester on the VFTO is related to the positions of the arrester and an action point of the isolating switch.

As described above, all current VFTO suppression methods need to introduce new components into the GIS loop, which increases the complexity of GIS assembly and the probability of mechanical or electrical failure, and the reliability of the disconnector cannot be guaranteed.

The invention provides a method for realizing the separation of a power frequency signal and a high-frequency VFTO signal by using an electromagnetic wave dispersion principle according to the huge difference of the frequency spectrums of the power frequency signal and the high-frequency VFTO signal, skillfully utilizes the original primary bus and a shell on the basis of not changing a GIS integrated structure and not introducing an action part, newly designs a high-damping channel only aiming at the high-frequency VFTO signal, and solves the problem of inhibiting the VFTO by increasing the loss of the functional quantity of the high-frequency VFTO signal.

Disclosure of Invention

The invention provides a VFTO restraining structure based on an electromagnetic wave dispersion principle, aiming at the technical problems in the prior art, and the VFTO restraining structure is suitable for a high-frequency damping bus unit and a high-frequency damping shell unit of GIS integrated equipment, wherein the high-frequency damping bus comprises a GIS pipeline guide rod and a sleeve, and the VFTO restraining structure is respectively formed on the outer surface of the high-frequency damping bus and the inner surface of the high-frequency damping shell. The VFTO restraining structure is based on a GIS primary bus or a GIS shell, the layering of a conductor structure is realized, and a power frequency signal and a high-frequency VFTO signal channel are formed. The power frequency signal channel is an original primary bus conductor, the original through-flow characteristic and structure are not influenced, and the engineering applicability is strong; the high-frequency VFTO signal channel is formed on the outer surface of a GIS primary bus and the inner surface of a GIS shell respectively, the spiral groove type damping structure made of a high-permeability and low-conductivity conductive material is adopted, the impedance of the high-frequency VFTO signal channel is remarkably improved, the functional quantity loss of GIS integrated equipment under high frequency is increased, the amplitude of the VFTO is reduced, and the attenuation and the suppression of the VFTO energy are realized.

The VFTO restraining structure realizes the separation of power frequency signals and high-frequency VFTO signals and the layering of conductor structures of power frequency signals and high-frequency VFTO signal channels through an insulating layer.

The technical scheme for solving the technical problems is as follows:

on one hand, the invention provides a very fast transient overvoltage VFTO restraining structure based on an electromagnetic wave dispersion principle, wherein the restraining structure is coated on the outer side of a primary bus of a gas insulated substation GIS or arranged on the inner side of a shell of the gas insulated substation GIS; the suppression structure comprises an insulating layer, a damping resistance layer and a semiconductor layer; the GIS primary bus is a GIS conducting rod and is used for normally transmitting power frequency signals. And the GIS shell is used for mechanically supporting the GIS integrated equipment.

If the suppression structure is coated on the outer side of a primary bus of the gas insulated substation GIS, the primary bus, the insulating layer, the damping resistance layer and the semiconductor layer are sequentially arranged from inside to outside;

if the suppression structure is arranged on the inner side of the shell of the GIS, the shell, the insulating layer, the damping resistance layer and the semiconductor layer of the GIS are arranged from outside to inside in sequence;

the insulating layer is used for separating a normal power frequency signal and a high-frequency very-fast transient overvoltage VFTO signal.

Furthermore, the insulating layer is formed by spraying insulating material particles onto the outer surface of a primary bus of the gas insulated substation or the inner surface of a housing of the gas insulated substation in a regional cold spraying mode, and forming a plurality of sections of insulating layers through collision deposition.

Furthermore, in the insulating layer forming process, a plurality of regions are divided on the outer surface of the primary bus or the inner surface of the shell for carrying out cold spraying on insulating material particles, and the axial distance between any two adjacent regions is equal.

Furthermore, the damping resistance layer is formed in gaps between the surface of the insulating layer and the multiple sections of insulating layers by adopting an electroplating process, and the surface of the insulating layer is sequentially cleaned, sensitized, activated and electroplated by adopting the electroplating process, so that the surface and the gaps form a uniform and tight damping resistance layer, and the damping resistance layer is well and reliably electrically connected with the primary bus of the gas insulated substation GIS or the shell of the gas insulated substation. The power frequency signal is transmitted through a GIS primary bus, and the high-frequency VFTO signal is transmitted through a damping resistance layer.

The damping resistance layer is used for providing VFTO circulation route when very fast transient state overvoltage VFTO high frequency signal transmits along the damping resistance layer, is showing and is improving high frequency impedance, absorbs VFTO travelling wave energy, increases active loss, reduces VFTO's amplitude.

Furthermore, the damping resistance layer is made of a conductive material with high magnetic conductivity and low electric conductivity. The higher the magnetic permeability and the lower the electrical conductivity of the conductive material, the higher the impedance of the high-frequency VFTO signal channel, and the better the suppression effect on VFTO.

Furthermore, after the damping resistance layer is formed through an electroplating process, the damping resistance layer is subjected to grooving processing through a grooving process to form a plurality of spiral grooves, so that the spiral groove type damping resistance layer is formed.

Further, the semiconductor layer is made of a semiconductor material with high carrier concentration and is formed on the surface of the damping resistance layer and in the spiral groove by a coating process; the semiconductor layer is used for balancing the electric field distribution on the outer surface of the whole structure, so that the discharge accident caused by overhigh local field intensity is avoided, and the insulation performance of the GIS integrated equipment is not influenced.

The invention has the beneficial effects that: according to the VFTO restraining structure, the insulation layer and the spiral groove-shaped damping resistance layer are additionally arranged on the outer surface of the GIS primary bus or the inner surface of the GIS shell, so that a normal power frequency signal is separated from a high-frequency VFTO signal, the high-frequency VFTO signal passes through the spiral groove-shaped damping resistance layer of the high-damping resistance, the functional quantity loss is increased, the VFTO amplitude is reduced, the VFTO is restrained, and the working reliability of secondary equipment is improved. The outer surface of the spiral groove type damping resistance layer is coated with the uniform semiconductor layer, so that the electric field distribution of the outer surface of the whole structure is improved, the discharge accident caused by overhigh local field intensity is avoided, and the insulation performance of the GIS integrated equipment is not influenced. The damping resistance value of the spiral groove type damping resistance layer is obviously increased along with the increase of the frequency, so that the damping effect is better when the VFTO restraining structure of the invention attenuates energy with higher frequency in VFTO signals. A damping resistance layer with uniformity, flatness and high bonding strength is formed on the surface and the gap of the insulating layer through an electroplating process, and a GIS primary bus or a GIS shell can be well and reliably electrically connected with the spiral groove type damping resistance layer without adopting an electrical connecting piece. A plurality of spiral grooves are formed on the electroplated damping resistance layer through a grooving process, the adopted process flow is few, and the requirement on production equipment is low. The high-frequency current flow area is reduced through the slots, the flow length is increased, the high-frequency impedance is obviously improved, and the functional capacity loss of the spiral slot type damping resistance layer is increased.

On the other hand, the invention also provides GIS integrated equipment of the gas insulated substation, which comprises a high-frequency damping bus unit and a high-frequency damping shell unit, wherein the high-frequency damping bus comprises a GIS pipeline guide rod and a sleeve.

The high-frequency damping bus unit comprises a GIS primary bus, an insulating layer on the outer surface of the primary bus, a spiral groove type damping resistance layer and a semiconductor layer. The high-frequency damping shell unit comprises a GIS shell, an insulating layer on the inner surface of the GIS shell, a spiral groove type damping resistance layer and a semiconductor layer. The GIS primary bus is used for normally transmitting signals under the power frequency condition, and the GIS shell is used for mechanically supporting GIS integrated equipment.

And the insulating layer is formed into a plurality of sections of insulating layers after collision and deposition by spraying insulating material particles onto the outer surface of the primary bus and the inner surface of the shell through cold. And in the cold spraying process, the outer surface of the primary bus and the inner surface of the shell are subjected to regional cold spraying, and the axial distances between two adjacent insulating layers are equal.

The spiral groove type damping resistance layer is formed on the surface of the insulating layer and in the gap uniformly and strictly through an electroplating process, and then the spiral groove of the damping resistance layer is processed through a milling machine.

The spiral groove type damping resistance layer is made of a conductive material with high magnetic conductivity and low electric conductivity.

The semiconductor layer is made of semiconductor materials with high carrier concentration and is uniformly coated on the outer surface of the spiral groove type damping resistance layer and in the groove.

The beneficial effects are that: the GIS integrated equipment starts from a primary equipment structure, and realizes the separation of a power frequency signal and a high-frequency VFTO signal through an insulating layer, so that the high-frequency VFTO signal passes through a spiral groove type damping resistance layer of a high damping resistance, the functional quantity loss of the GIS integrated equipment is obviously increased, and the VFTO is restrained. The invention does not change the structure of the primary bus and the shell and has no action part, thereby simplifying the design structure of the GIS high-frequency damping bus and the high-frequency damping shell, being applicable to the improvement of the primary bus structure and the shell structure of the existing GIS integrated equipment and guiding the design of the primary bus structure and the shell structure of the novel GIS integrated equipment.

Drawings

Fig. 1 is a schematic diagram of VFTO formation.

Fig. 2 is a radial cross-sectional view of a VFTO suppressing structure.

FIG. 3 is a side view of a VFTO suppressing structure.

Fig. 4 is an axial sectional view of a high-frequency damping bus bar unit employing a VFTO suppressing structure.

Fig. 5 is an axial sectional view of a high frequency damping housing unit employing a VFTO suppressing structure.

In the figure: 1, GIS primary bus; 2. an insulating layer; 3. a spiral groove-shaped damping resistance layer; 4. a semiconductor layer; 5. an insulating layer damping conductive material filling region; and 6.GIS shell.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

Fig. 1 is a schematic diagram of VFTO formation. Two sections of GIS primary buses are arranged at two ends of the isolating switch and respectively provided with electromagnetic energyW ₁AndW ₂when the isolating switch is switched on and off, electromagnetic energy can be transferred and redistributed. Because the GIS primary bus has good conductivity, the energy loss of electromagnetic energy in the redistribution process is little, the amplitude of the generated traveling wave formed by multiple times of refraction and reflection can reach 3p.u., and the frequency can reach hundreds of MHz, namely VFTO is formed.

Fig. 2 is a radial cross-sectional view of a VFTO suppressing structure according to the present invention, taking a high frequency damping bus bar unit as an example. As shown in fig. 2, the VFTO suppressing structure includes: GIS primary bus 1, insulating layer 2, spiral groove type damping resistance layer 3 and semiconductor layer 4. And the GIS primary bus 1 is a GIS conducting rod. The insulating layer 2 is made of insulating materials, specifically mica particles, boron nitride particles and the like, and is formed on the outer surface of the bus and the inner surface of the shell in a regional cold spraying mode, the axial distance between any two adjacent sections of insulating layers is equal, and the length of the axial distance can be specifically set as required. The spiral groove type damping resistance layer 3 is made of a conductive material with high magnetic conductivity and low conductivity, specifically, a nickel-iron alloy, a glass-mullite alloy and the like, is formed on the surface of the insulating layer and in the gap in an electroplating mode, and then the electroplated damping resistance layer is subjected to grooving processing by a milling machine to finally form a spiral groove type structure, specifically, spiral groove parameters can be set according to needs, wherein the spiral groove type damping resistance layer and a GIS primary bus realize good and reliable electrical connection through the damping conductive material in the gap between the two sections of the insulating layers. The semiconductor layer 4 is made of a semiconductor material with high carrier concentration, specifically indium tin oxide, acetylene black carbon and the like, and is formed on the outer surface of the spiral groove type damping resistance layer by a coating method, so that the electric field distribution of the outer surface of the whole structure is improved, and the local discharge caused by overhigh local field intensity is avoided.

Wherein, the formation of the insulating layer adopts a cold spraying process, which comprises the following steps:

(1) the GIS primary bus and the shell are polished on line through polishing equipment, and the roughness of the outer surface of the bus and the inner surface of the shell is reduced;

(2) combining a mixture of pressurized gas and particles of insulating material, selectively varying the temperature of the pressurized gas;

(3) accelerating the insulating material particles in the direction of the outer surface of the primary bus and the inner surface of the shell, and depositing and forming a plurality of sections of insulating layers with equal axial intervals by utilizing the fact that the accelerated insulating material particles collide the surface of the conductor.

The forming of the damping resistance layer adopts an electroplating process, and the method comprises the following steps:

(1) soaking the surface of the workpiece in an aqueous solution of an anionic compound, and depositing a compact charged multilayer reducing film on the surface of the workpiece to form a modified surface;

(2) contacting the modified surface with an aqueous solution containing permanganate ions to form a manganese dioxide adsorption layer on the modified surface, and forming a conductive polymer layer on the surface of the manganese dioxide adsorption layer;

(3) and taking the conductive polymer layer as a cathode and the metal plating solution as an anode, immersing the workpiece in the electroplating solution for electroplating treatment, and taking the workpiece out for washing and drying after the electroplating is finished.

Wherein, the formation of the spiral groove type damping resistance layer adopts a milling machine slotting process, and the method comprises the following steps:

(1) fixing the workpiece on a cleaning device for cleaning, and drying the workpiece by a fan;

(2) fixing the workpiece on a fixing device, and fixing the fixing device on a milling machine workbench;

(3) starting the milling machine, and slotting a spiral groove on the workpiece;

(4) and (5) putting the workpiece with the groove into a collecting device for cooling.

Wherein, the formation of the semiconductor layer adopts a coating process, which comprises the following steps:

(1) cleaning the surface of a workpiece and putting the workpiece into a drying box for drying treatment, wherein the temperature of the dried workpiece is room temperature;

(2) putting the dried workpiece into a coating tank for coating;

(3) putting the coated workpiece into a curing furnace for heating and curing treatment;

(4) and (4) putting the solidified workpiece into a cooling station for cooling treatment to room temperature.

Fig. 3 is a side view of a VFTO suppression structure according to the present invention, taken as an example of a high frequency damped bus bar unit. The dotted line indicates the distribution of the grooves of the spiral groove-type damping resistance layer formed by the spiral. The spiral groove type damping resistance layer is in good and reliable electrical connection with the GIS primary bus 1 through the insulating layer damping conductive material filling area 5. The surface of the spiral groove type damping resistance layer and the spiral groove are coated with semiconductor materials, and finally a uniform semiconductor layer 4 is formed.

Fig. 4 is an axial sectional view of a high frequency damped bus bar unit employing the VFTO suppressing structure of the present invention. As shown in fig. 4, the high-frequency damping bus bar unit includes a GIS primary bus bar 1, an insulating layer 2, a spiral groove-shaped damping resistance layer 3, and a semiconductor layer 4. The insulating layer 2 is formed on the surface of the GIS primary bus 1 by a regional cold spraying method, and a gap with a fixed axial distance exists between any two adjacent insulating layers. The spiral groove type damping resistance layer 3 is formed on the surface and in the gap of the insulating layer through an electroplating process and a grooving process, and spiral groove parameters can be set specifically according to requirements. The power frequency signal and the high-frequency signal are separated through the insulating layer, and the electric connection between the conducting rod and the spiral groove type damping resistance layer is realized through the damping conducting material in the gap of the insulating layer. The semiconductor layer 4 is formed on the surface of the spiral groove type damping resistance layer and in the groove through a coating process and is used for improving the electric field distribution of the outer surface of the whole structure.

Fig. 5 is an axial sectional view of a high frequency damped housing unit employing the VFTO suppressing structure of the present invention. As shown in fig. 5, the high-frequency damping housing unit includes a GIS housing 6, an insulating layer 2, a spiral groove-shaped damping resistance layer 3, and a semiconductor layer 4. The insulating layer 2 is formed on the inner surface of the GIS shell 6 by a regional cold spraying method, and a gap with a fixed axial distance exists between any two adjacent sections of insulating layers. The spiral groove type damping resistance layer 3 is formed on the surface and in the gap of the insulating layer through an electroplating process and a grooving process, and spiral groove parameters can be set specifically according to requirements. The power frequency signal and the high-frequency signal are separated through the insulating layer, and the shell is electrically connected with the spiral groove type damping resistance layer through the damping conducting material in the gap of the insulating layer. The semiconductor layer 4 is formed on the surface of the spiral groove type damping resistance layer and in the groove through a coating process and is used for improving the electric field distribution of the outer surface of the whole structure.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An ultra-fast transient overvoltage suppression structure is characterized in that the suppression structure is coated on the outer side of a primary bus of a gas insulated substation or arranged on the inner side of a shell of the gas insulated substation; the suppression structure comprises an insulating layer, a damping resistance layer and a semiconductor layer;

if the suppression structure is coated on the outer side of the primary bus of the gas insulated substation, the primary bus, the insulating layer, the damping resistance layer and the semiconductor layer are sequentially arranged from inside to outside;

if the suppression structure is arranged on the inner side of the shell of the gas insulated substation, the shell, the insulating layer, the damping resistance layer and the semiconductor layer of the gas insulated substation are arranged from outside to inside in sequence.

2. The suppression structure according to claim 1, wherein the insulating layer is formed by performing fractional cold spraying on insulating material particles on the outer surface of a primary bus of the gas-insulated substation or the inner surface of a housing of the gas-insulated substation to form a plurality of sections of insulating layers through collision deposition.

3. The suppressing structure according to claim 2, wherein in the insulating layer forming process, a plurality of regions are divided on the outer surface of the primary bus bar or the inner surface of the housing, and insulating material particles are subjected to cold spraying, and the axial distances between any two adjacent regions are equal.

4. The suppression structure according to claim 1, wherein the damping resistance layer is formed in a gap between the surface of the insulating layer and the plurality of sections of insulating layers by an electroplating process, so that the damping resistance layer is electrically connected with the primary bus of the gas-insulated substation or the housing of the gas-insulated substation.

5. The suppression structure of claim 4, wherein the damping resistance layer is made of a high permeability, low conductivity conductive material.

6. The suppressing structure according to claim 4, wherein the damping resistance layer is formed by a plating process and then a plurality of spiral grooves are formed in the damping resistance layer by a grooving process to form a spiral groove type damping resistance layer.

7. The suppression structure according to claim 6, wherein the semiconductor layer is made of a semiconductor material with a high carrier concentration and is formed in the surface of the damping resistance layer and in the spiral groove by a coating process.

8. An integrated device of a gas insulated substation, characterized by comprising a high-frequency damping bus unit and a high-frequency damping housing unit, wherein the high-frequency damping bus unit and the high-frequency damping housing unit both comprise the very fast transient overvoltage suppression structure according to any one of claims 1 to 7.

9. The integrated apparatus of claim 8, wherein the high frequency damping bus unit comprises a gas insulated substation pipe guide and bushing, and the dampening structure is molded on an outer surface of the high frequency damping bus.

10. The integrated apparatus of claim 8, wherein the dampening structure is molded to the high frequency damping housing inner surface.