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CN-121975273-A - Low-temperature-resistant grounding resistance-reducing material and preparation method thereof

CN121975273ACN 121975273 ACN121975273 ACN 121975273ACN-121975273-A

Abstract

The invention relates to a low-temperature-resistant grounding resistance-reducing material and a preparation method thereof, and relates to the technical field of grounding materials, wherein the low-temperature-resistant grounding resistance-reducing material comprises the following components in parts by weight: the preparation method comprises the steps of emulsion system preparation, microcapsule preparation, conductive framework construction, compounding, forming and curing. The invention realizes the long-acting stable resistance reduction of the grounding resistance-reducing material in a low-temperature environment by adopting the physical barrier effect, and further reduces the later maintenance cost of the grounding engineering.

Inventors

  • LI PEI
  • ZHENG YU
  • WANG YANG
  • CAO HUI
  • ZHANG CHUNBO
  • TAI YUFENG
  • ZHOU SHIYU
  • DONG HONGDA
  • KANG XUE
  • ZHANG HAO
  • Shi Qiaofan
  • LIU JUNBO
  • ZHANG YAN
  • LUAN JINGYAO

Assignees

  • 国网吉林省电力有限公司电力科学研究院
  • 吉林省电力科学研究院有限公司
  • 中北大学

Dates

Publication Date
20260505
Application Date
20260323

Claims (10)

  1. 1. The low-temperature-resistant grounding resistance-reducing material is characterized by comprising, by mass, 15-25 parts of a carbon-based conductive material, 50-60 parts of a matrix material, 12-20 parts of microcapsules, 1-2 parts of a silane coupling agent, 2-3 parts of a dispersing agent and 6-10 parts of deionized water; the carbon-based conductive material comprises 12-18 parts of graphite powder, 2-4 parts of carbon nanotubes and 1-3 parts of graphene, wherein the matrix material comprises nitrile rubber modified epoxy vinyl resin, and the mass of the nitrile rubber accounts for 11-15 wt% of the mass of the epoxy vinyl resin; The microcapsule comprises 8.4-14.0 parts of a capsule core and 3.6-6.0 parts of a shell layer, wherein the capsule core comprises ethylene glycol, calcium chloride and deionized water, and the mass ratio of the ethylene glycol to the calcium chloride to the deionized water is 4-6:1.5-2.5:2.5-3.5; the shell layer comprises polyurethane, and the dispersing agent is one or a mixture of more of polyacrylamide, sodium polycarboxylate and sodium lignin sulfonate.
  2. 2. The low-temperature-resistant grounding resistance-reducing material according to claim 1, wherein the shell layer further comprises nano silicon dioxide, and the mass ratio of the nano silicon dioxide to polyurethane is 1:16-24.
  3. 3. The low temperature resistant, ground resistance reducing material of claim 2, wherein the nanosilica is pretreated nanosilica; The pretreatment method comprises the steps of drying nano silicon dioxide for 1-3 hours at the temperature of 100-110 ℃, naturally cooling to room temperature, adding a silane coupling agent solution with the mass fraction of 4-6wt%, stirring for 20-30 minutes at the temperature of 30-40 ℃ and the speed of 100-300 rpm, separating by vacuum suction filtration, drying filter residues at the constant temperature of 75-85 ℃ for 0.8-1.2 hours, naturally cooling to room temperature, crushing and sieving with a 200-mesh sieve to obtain pretreated nano silicon dioxide, wherein the mass ratio of the nano silicon dioxide to the silane coupling agent solution is 1:7-9.
  4. 4. The low-temperature-resistant grounding resistance-reducing material according to claim 3, wherein the shell layer further comprises an acrylic polymer, the mass ratio of nano silicon dioxide to polyurethane to acrylic polymer is 1:16-24:37-56, and the preparation method of the acrylic polymer comprises the following steps: Pre-emulsifying 90-110 parts of deionized water, 2-3 parts of sodium dodecyl sulfate, 60-70 parts of butyl acrylate and 1.5-2.5 parts of methacrylic acid, stirring at 20-25 ℃ for 20-40min to obtain a core layer pre-emulsion, and pre-emulsifying 10-20 parts of isooctyl acrylate, 6-10 parts of styrene, 0.8-1.0 part of methacrylic acid, 2-4 parts of aminopolysiloxane and 0.4-0.6 part of N-methylolacrylamide to obtain a shell layer pre-emulsion; Seed polymerization, namely adding 45-55 parts of deionized water, 0.4-0.6 part of polyoxyethylene nonylphenol ether and 0.08-0.12 part of ammonium persulfate into a reaction kettle, heating to 75-85 ℃, adding 8-10wt% of a core layer pre-emulsion, and preserving heat for 25-35 min to obtain seed latex; core layer polymerization, namely dripping the residual core layer pre-emulsion for 1-3 hours, and preserving heat for 0.8-1.0 hour at 75-85 ℃ to obtain core layer latex; shell copolymerization, namely dropwise adding a shell pre-emulsion for 0.8-1.0 h, adding 0.08-0.12 part of ammonium persulfate every 20min in the dropwise adding process, and preserving heat for 1-3 h at 75-85 ℃; And (3) post-treatment, namely cooling to 55-65 ℃, regulating the pH to 7.5-8.0 by ammonia water, preserving the temperature for 0.8-1.2 h, filtering and discharging, and vacuum drying for 3-5 h under the conditions of vacuum degree of-0.06-0.09 MPa and temperature of 40-60 ℃ to obtain the acrylic ester polymer.
  5. 5. The low temperature resistant grounding resistance reducing material according to any one of claims 1 to 4, wherein the capsule core further comprises pentaerythritol, and the mass ratio of pentaerythritol to ethylene glycol, calcium chloride and deionized water is 0.4-0.6:4-6:1.5-2.5:2.5-3.5.
  6. 6. A method for preparing the low temperature resistant grounding resistance-reducing material according to any one of claims 1 to 5, comprising the steps of: The preparation of an emulsion system comprises the steps of mixing ethylene glycol, calcium chloride and deionized water according to a mass ratio, stirring uniformly at 20-25 ℃ to obtain a capsule core solution, adding the capsule core solution into an emulsion accounting for 2-3wt% of the capsule core solution, and emulsifying at 4000-6000 rpm for 20-30 min to obtain the emulsion system, wherein the emulsion comprises span-80 and tween-80, and the mass ratio of span-80 to tween-80 is 1-2:1; the microcapsule preparation comprises an interfacial polymerization step, wherein the interfacial polymerization step comprises the following steps: adding the shell component into an emulsion system, and reacting for 1-2 hours at 50-60 ℃; the conductive framework is constructed by adding graphite powder, carbon nano tubes and graphene into 1/3 deionized water, stirring to form a suspension system, and performing ultrasonic dispersion for 30-40 min by 300-500W to form a uniform carbon-based conductive system; Compounding and molding, namely adding a silane coupling agent and a dispersing agent into a carbon-based conductive system, stirring at 200-400 rpm for 10-15 min, adding microcapsules, continuously stirring for 8-12 min, adding nitrile rubber modified epoxy vinyl resin, stirring at 600-800 rpm for 25-35 min to form uniform composite slurry, adding the rest deionized water, stirring uniformly, vacuum defoaming for 8-12 min under the vacuum degree of-0.08 MPa, and pouring into a mold for molding; The method comprises the steps of firstly heating the formed slurry to 35-45 ℃ from room temperature, heating to 1-3 ℃ per minute, curing for 4-6 hours, heating to 65-75 ℃ at 0.8-1.2 ℃ per minute, curing for 2-4 hours, and naturally cooling to room temperature after curing is completed to obtain the low-temperature-resistant grounding resistance-reducing material.
  7. 7. The method for preparing the low-temperature-resistant grounding resistance-reducing material according to claim 6, wherein in the interfacial polymerization step, methyltrimethoxysilane accounting for 2-3wt% of the shell mass is added in the last 30min of the reaction, and stirring is continued until the reaction is finished.
  8. 8. The method for preparing a low temperature resistant, electrically conductive resistance-reducing material according to claim 7, wherein the microcapsule preparation step further comprises a pre-crosslinking step, the pre-crosslinking step being provided before the interfacial polymerization step; The pre-crosslinking step comprises the steps of mixing a shell component and diisocyanate, and stirring and pre-crosslinking at 45-55 ℃ and 100-200 rpm for 20-40 min, wherein the addition amount of the diisocyanate is 10-15 wt% of the mass of the shell material.
  9. 9. The method according to any one of claims 6 to 8, wherein the microcapsule preparing step further comprises an annealing step, the annealing step being provided after the interfacial polymerization step; The annealing step comprises the steps of preserving heat at 25-35 ℃ for 0.8-1.2 h, preserving heat at 5-15 ℃ for 1-2 h, and standing at 0-5 ℃ for 10-20 min in sequence.
  10. 10. Use of the low temperature resistant, ground resistance reducing material of any one of claims 1-5, or prepared according to the method of any one of claims 6-9, in a cold area ground engineering, characterized in that the applied ambient temperature ranges from-40 ℃ to 25 ℃.

Description

Low-temperature-resistant grounding resistance-reducing material and preparation method thereof Technical Field The invention relates to the technical field of grounding materials, in particular to a low-temperature-resistant grounding resistance-reducing material and a preparation method thereof. Background In the operation process of the power system, the grounding resistor is a key parameter for guaranteeing the safe and stable operation of the system, the value of the grounding resistor directly determines the height of the ground potential rise during short-circuit faults, the power equipment is easily damaged due to the excessively high ground potential rise, and meanwhile, the safety risk of personnel overcurrent injury is brought. In particular, in a frozen soil environment, soil loses plasticity at low temperature to form solid blocks, so that the contact resistance between a grounding body and the soil is increased, soluble salt cannot form conductive ions due to the fact that no solution exists in the soil, the soil resistivity of frozen soil is improved by several times compared with that of non-frozen soil, in addition, a frozen soil area is in a high-cold high-altitude area, the topography is complex, the mechanical construction difficulty is high, and therefore the problem of how to effectively reduce the resistance in the frozen soil area is to be solved. In order to solve the technical problems, chinese patent application publication No. CN113012845A, publication No. 2021, no. 6 and No. 22 proposes a frozen soil grounding resistance-reducing filler, in the application, the filler comprises a conductive substance, a dispersing agent, an antifreezing agent and water, wherein the conductive substance is one or a mixture of a plurality of graphite, sodium chloride and potassium chloride, the dispersing agent is polyacrylamide, the antifreezing agent is glycol or glycerol, and the components are mixed to prepare a finished product. The frozen soil resistance-reducing filler has the characteristics of low condensation temperature, strong permeability, stable soil plasticity and the like, and effectively improves the plasticity and the conductivity of frozen soil around a grounding body, so that the grounding resistance is reduced. However, the inventor finds that although the plasticity and the conductivity of the frozen soil are effectively improved by the technical scheme, the long-term stable resistance reduction effect cannot be realized in the long-term application of the frozen soil scene, and the technical scheme is characterized in that the antifreeze glycol and the glycerol are volatile water-soluble micromolecules, the glycol and the glycerol are slowly volatilized, so that the antifreeze performance and the conductivity of the filler can be quickly attenuated with time, the freezing point of the filler gradually rises, the frozen soil is finally frozen again, the contact resistance rises suddenly, and the long-term effect of the resistance reduction effect cannot be ensured. Disclosure of Invention The invention provides a low-temperature-resistant grounding resistance-reducing material and a preparation method thereof, aiming at solving the problem that the existing grounding resistance-reducing material has poor long-term stability of resistance-reducing effect in a low-temperature environment. In a first aspect, the invention provides a low-temperature-resistant grounding resistance-reducing material, which adopts the following technical scheme: The low-temperature-resistant grounding resistance-reducing material comprises, by mass, 15-25 parts of a carbon-based conductive material, 50-60 parts of a matrix material, 12-20 parts of microcapsules, 1-2 parts of a silane coupling agent, 2-3 parts of a dispersing agent and 6-10 parts of deionized water; the carbon-based conductive material comprises 12-18 parts of graphite powder, 2-4 parts of carbon nanotubes and 1-3 parts of graphene, wherein the matrix material comprises nitrile rubber modified epoxy vinyl resin, and the mass of the nitrile rubber accounts for 11-15 wt% of the mass of the epoxy vinyl resin; The microcapsule comprises 8.4-14.0 parts of a capsule core and 3.6-6 parts of a shell layer, wherein the capsule core comprises ethylene glycol, calcium chloride and deionized water, and the mass ratio of the ethylene glycol to the calcium chloride to the deionized water is 4-6:1.5-2.5:2.5-3.5; the shell layer comprises polyurethane, and the dispersing agent is one or a mixture of more of polyacrylamide, sodium polycarboxylate and sodium lignin sulfonate. According to the technical scheme, the carbon-based conductive material adopts a ternary composite system of graphite powder, carbon nanotubes and graphene, so that a continuous conductive path is formed, the resistivity of a material body is reduced, the chemical property of the material is stable, oxidation failure can not occur during long-term burying, the resistance-reducing