Ujenzi wa kifugaji cha mizigo ya kiwango kikuu

I. Fungo za Mfumo wa Mviringo wa Kifasi na Muhimu ya Ujenzi

Mfumo wa mviringo wa kifasi wa mitindo ya umeme magumu ni muundo wa mshini wa kimviringo unaozuiwa nje ya kiwango cha usafi, unaotumia aina kama vile mfuko wa ng'ombe, mfuko wa alluminium, na nguo ya mamba ya chuma. Fungo zake muhimu zinazozingatia ni uzalishaji wa usalama (kuzuia upindelele na maongezi ya nje), uzalishaji wa ukabilibishaji wa mauti na mizizi (kuzimia maji na matokoto ya ardhi), kuweka mshini ya kimviringo (kuondokana na mafanikio ya kimviringo kwa mazingira), na kutumia njia ya kukabiliana (kusaidia utaratibu mzuri wa uhamiaji wa mafunzo). Mara tu atakipoteza ubora wake, mfumo wa mviringo wa kifasi unaweza kusababisha jirani kwenye kiwango cha usafi, kubadilisha mfumo wa umeme katika eneo fulani, au hata kushindwa kwa mzunguko wa umeme na kuchomoza. Kwa hiyo, ujenzi wa kutosha unachotathmini tabaini tofauti za upindelele ni muhimu sana kwa uhakika ya muda wa miamala ya mzunguko wa umeme.

II. Tathmini na Uchanganuzi wa Matukio Kabla ya Ujenzi

(A) Utambuzi wa Aina za Upindelele

• Upindelele wa Kimakazi: Inaonekana kama mafuriko, mabomoleo, au mafuriko kwenye kifasi, inayotokana na mzunguko wa mifano au mafuriko ya vitu vya kumea wakati wa uzalishaji, au kupindeka kutokana na muda mrefu wa kusogelea.

• Ukabilibishaji wa Kimviringo: Umeme wa kimviringo wa ardhi au mazingira ya asidi au basi yanaweza kusababisha ukabilibishaji wa kifasi, inayoweza onekana kama mabomoleo yaliyofika, rust, mafuriko, na matokeo ya ukabilibishaji wa asidi (kifasi cha alluminium) au sufuri (kifasi cha ng'ombe).

• Uhaba wa Moto: Uhamiaji wa muda mrefu unaweza kusababisha ukabilibishaji wa mteremko wa kifasi, inayoweza onekana kama mabomoleo na kupungua, inayoweza kupatikana kwenye viungo au eneo ambavyo hakuna mafanikio ya moto.

(B) Tumia Teknolojia za Kutathmini

• Utathmini wa Macho: Tumia mashine ya kutathmini au macho ya moto ili kutathmini paa ya kifasi, inayoweza kutathmini vipindi vinavyoonekana na moto.

• Mtihani wa Kifasi wa Kusidikisha Moto: Tumia moto wa DC (10 kV kwa dakika moja) ili kutathmini uwiano wa kifasi. Uongezaji wa moto wa kusidikisha (>10 μA) unahitaji upindelele.

• Kutathmini Mafanikio ya Kimviringo: Tumia sensa za moto ya juu (HFCT) ili kupata maelezo ya mafanikio kwenye vipindi vilivyopondekwa, inayoweza kutathmini mpaka ±0.5 m.

• Tathmini wa Ukabilibishaji wa Ardhi: Pata sampuli za ardhi kutoka kwenye mazingira ya kusimamia mzunguko wa umeme ili kutathmini pH, ukabilibishaji wa chloride, na ukabilibishaji wa umeme wa kimviringo, inayoweza kutathmini mbinu za kutumia midhibiti.

III. Chaguo la Midhibiti na Zana za Ujenzi

(A) Midhibiti Ya Msingi

• Midhibiti ya Kutumia Kifasi:

• Sleeve ya Alluminium Alloy: Inapatikana kwa ajili ya ujenzi wa kifasi cha alluminium, inayoendelea na ukabilibishaji mzuri. Lazima iwe sawa na urefu wa mzunguko wa umeme (ukabilibishaji ≤ ±0.5 mm).

• Tape ya Lead-Tin Alloy: Inatumika kwa ajili ya ujenzi wa kifasi cha ng'ombe, inayoendelea na ukabilibishaji chache (~183°C), rahisi kwa ajili ya ujenzi wa moto, inayohitajika GB/T 12706.2 ukabilibishaji (ukabilibishaji wa ng'ombe ≥ 99.9%).

• Stainless Steel Corrugated Tube: Kwa upindelele wa nguo ya mamba, inayojengwa kutumia chuma cha 304, urefu wa mtaani ≥ 0.8 mm, inayoweza kusaidia kwa mifano na mizizi ya ardhi.

• Midhibiti ya Usalama na Kutumia:

• Cross-Linked Polyethylene (XLPE) Heat-Shrink Tubing: Inapungua kwenye 120–140°C, ratio ya kupungua ≥ 2:1, ukabilibishaji wa kupungua ≥ 25 kV/mm, inahitaji adhesive ya moto kwa ajili ya kutumia.

• Silicone Rubber Cold-Shrink Tubing: Inatumika kwa ajili ya kutumia, haihitaji moto, inayoweza kutumika kwenye mazingira machafu, ukabilibishaji wa Shore hardness 60 ± 5 Shore A, tanδ ≤ 0.003 (20°C, 50 Hz).

• Butyl Rubber Sealing Tape: Inatumika kama sota ya msingi, ukabilibishaji wa kusogegeza ≥ 3 MPa, ukabilibishaji wa kusogegeza ≥ 400%, ukabilibishaji wa muda mrefu unaweza kusogegeza ≥ 80% baada ya 100°C × 168 h.

• Midhibiti ya Ukabilibishaji:

• Zinc-Aluminum Alloy Sacrificial Anode: Kwa mazingira ya ukabilibishaji wa ardhi, ukabilibishaji wa anode ≥ 99.5%, ukabilibishaji wa mafunzo ≥ 15 mA/m², ukabilibishaji wa muda mrefu ≥ 20 miaka.

• Polyvinyl Chloride (PVC) Corrosion-Resistant Tape: Urefu ≥ 0.4 mm, ukabilibishaji wa kusogegeza ≥ 18 MPa, ukabilibishaji wa mazingira ≥ 1000 h.

(B) Zana Zenye Maundogo

• Zana za Kuandaa: Grindera ya pembeni (na wheel ya alumina ya 80-grit), brush ya mamba, cleaner ya ethanol isiyonena, scraper ya chuma (kwa ajili ya kutumia).

• Zana za Kutumia: Hydraulic crimping tool (range ya 60–200 mm²), heat gun (temperature range 50–600°C), lead sealing dedicated torch (flame temperature ≤ 300°C).

• Zana za Kutathmini: Megohmmeter (2500 V, range 0–10000 MΩ), double-arm bridge (measurement ya contact resistance, accuracy ±0.1 μΩ), ultrasonic thickness gauge (resolution 0.01 mm).

IV. Mfano wa Ujenzi wa Mzunguko wa Umeme kulingana na Aina za Upindelele

(A) Ujenzi wa Upindelele wa Kimakazi (mfano wa kifasi cha alluminium)

• Uundaji wa Eneo lililo Upindelele

• Tumia grindera ya pembeni kutumia kifasi kilichopondekwa kwa njia ya pembeni, na urefu wa 5 mara ukabilibishaji wa upindelele (minimum ≥ 100 mm), inayoweza kutathmini kiwango cha usafi.

• Ondoa mafuriko kwenye mikundi ya kifasi kwa kutumia scraper ya chuma, tunda kwa uwezo wa chuma, osha na ethanol, na kudumisha kwa dakika ≥ 15 min.

• Ujenzi wa Kifasi

• Chagua sleeve ya alluminium alloy yenye urefu wa ndani wa 1 mm zaidi ya urefu wa mzunguko wa umeme, ondoa kwa uwezo wa conductive grease (filler ya nickel, volume resistivity ≤ 5×10⁻⁴ Ω·cm).

• Glide the sleeve over the damaged area, use a Staggered Crimping method, crimp from center to ends. After crimping, hexagonal opposite-side deviation ≤ ±0.1 mm, contact resistance ≤ 20 μΩ.

• Sealing and Anti-Corrosion Treatment

• Wrap butyl rubber sealing tape with 50% overlap, forming a sealing layer ≥ 3 mm thick, extending ≥ 50 mm beyond undamaged sheath on both ends.

• Install heat-shrink tubing, heat gradually from center to ends (120°C → 140°C) to avoid bubbles. After cooling, check uniform shrinkage (post-shrinkage wall thickness ≥ 2 mm).

• Wrap PVC corrosion-resistant tape externally in a half-overlap spiral, secure ends with stainless steel straps (torque 15–20 N·m).

(B) Electrochemical Corrosion Repair (Steel Armor + Lead Sheath Composite Sheath)

• Corrosion Product Removal

• Use sandblasting (quartz sand 80–120 mesh, pressure 0.4–0.6 MPa) to remove rust from steel armor, exposing gray-white metal base, surface roughness Sa2.5 grade.

• Trim lead sheath corrosion area with a lead plane, forming a smooth transition with slope ≥ 1:5 to avoid stress concentration.

• Sacrificial Anode Protection

• Symmetrically install 2 zinc-aluminum alloy anodes (100 mm × 50 mm × 10 mm) on both sides of the repair section, connected to steel armor via copper braid (cross-section ≥ 16 mm²), welded (lap length ≥ 30 mm, welding current 120–150 A).

• Fill gap between anode and cable sheath with petroleum jelly, encapsulate externally with high-density polyethylene (HDPE) housing to ensure full soil contact.

• Dual Sealing Structure

• Inner layer: cold-shrink silicone rubber tubing, inner wall coated with semiconductive water-blocking gel (volume resistivity 10–100 Ω·cm). Maintain at room temperature for 24 h after recovery for curing.

• Outer layer: pour epoxy resin (E-51 type, curing agent T-31, ratio 100:25), mold sealed at 0.2 MPa pressure, cure ≥ 48 h at 25°C. Post-cure Shore hardness ≥ 85 Shore D.

(C) Thermal Aging Cracking Repair (XLPE Insulated Cable)

• Crack Area Reinforcement

• Cut a V-groove along the crack direction (depth 1/3 of sheath thickness, angle 60°), fill with heat-resistant silicone rubber (temperature rating ≥ 180°C, tear strength ≥ 15 kN/m), level with scraper, cure at room temperature for 2 h.

• Wrap glass fiber cloth (0.2 mm thick, 16×16 threads/cm), impregnate with epoxy resin (solid content ≥ 70%) to form a reinforcement layer. Tensile strength ≥ 200 MPa after curing.

• Heat Dissipation Optimization

• Install aluminum heat sinks (1.5 mm thick, fin spacing 5 mm) externally on the repair section, bonded to sheath with thermal grease (thermal conductivity ≥ 1.5 W/(m·K)) to reduce local temperature rise (≤ 5°C).

• Monitor operating temperature with infrared thermal imager, ensuring temperature difference from undamaged section ≤ 2°C.

V. Quality Control and Acceptance Standards

(A) Key Parameter Testing

• Electrical Performance: Sheath insulation resistance ≥ 1000 MΩ (2500 V megohmmeter), partial discharge ≤ 5 pC (at 1.73U₀ voltage).

• Mechanical Performance: Impact resistance of repair section ≥ 10 J (at -30°C), bending radius ≥ 20 times cable outer diameter (no obvious deformation).

• Sealing Performance: After immersion test (room temperature, 24 h), sheath leakage current change rate ≤ 10%, no bubbles or water ingress.

(B) Long-Term Reliability Verification

• Accelerated Aging Test: Place repair sample in thermal aging chamber (135°C × 1000 h), after removal insulation resistance retention ≥ 80%, tensile strength degradation ≤ 20%.

• Soil Burial Test: Simulate actual laying environment, buried depth 1 m, duration 1 year, check for no corrosion perforation or seal failure.

VI. Safety Operation Regulations

• Power-Off Work Requirements: Follow "power-off - voltage test - grounding wire installation" procedure before repair. Hang "Do Not Close" warning signs on cable terminations, set safety barriers (distance ≥ 8 m) within work radius.

• Hot Work Management: When using torches or welding, equip dry powder fire extinguishers (ABC type, capacity ≥ 4 kg), clear flammable materials within 3 m, assign a dedicated supervisor.

• Personal Protective Equipment (PPE): Wear insulated gloves (35 kV rating), goggles, flame-resistant workwear. Use safety harness (static load test force 2205 N, hold 3 min without break) for work at heights (≥ 2 m).