Komprehensibong Solusyon para sa Pagpapahusay ng Performance ng Transmission Transformers: Pagsasama-sama ng Paggamit ng Cooling at Pagbawas ng Magnetic Circuit Losses

1. Background at Challenges

Sa patuloy na paglaki ng mga load sa kuryente at ang mas mahigpit na mga pamantayan para sa matatag na operasyon ng grid, ang mga transmission transformer ay nakaharap sa malubhang mga hamon sa kaugnay ng epektibidad ng operasyon, kontrol sa pagtaas ng temperatura, at matagal na reliabilidad. Ang sobrang mataas na temperatura ng operasyon ay nagpapabilis ng pagtanda ng mga materyales ng insulasyon, bumabawas sa buhay ng ekwipo, at nagdudulot ng mas mataas na panganib ng pagkasira. Ang mataas na magnetic circuit losses (karamihan ay iron loss at copper loss) ay bumabawas sa epektibidad ng paggamit ng enerhiya, nagreresulta sa hindi kinakailangang mga gastos sa operasyon. Upang tugunan ang dalawang pangunahing isyu na karaniwang natatagpuan sa mga transmission transformer—sobrang pagtaas ng temperatura at mataas na magnetic circuit losses—ginawa ang komprehensibong solusyon na ito.

2. Layunin ng Solusyon

• Malaking Pagbawas sa Temperatura ng Operasyon: Kontrolin ang temperatura ng langis sa itaas at temperature ng winding hotspot ng transformer sa ligtas na hangganan ng operasyon.
• Epektibong Pagbawas sa Magnetic Circuit Losses: Tumututok sa pagbabawas ng no-load losses (iron loss) at load losses (copper loss), at pagpapataas ng kabuuang epektibidad ng operasyon.
• Pagpapataas ng Reliabilidad ng Operasyon: Bawasan ang rate ng pagkasira dahil sa sobrang init at sobrang magnetic circuit losses, at palawakin ang buhay ng service ng transformer.
• Optimisasyon ng Total Life Cycle Cost: Ipaglaban ang ekonomikong epektibidad ng transformer sa pamamagitan ng pagbabawas ng enerhiya at pagbawas ng frequency ng maintenance.

3. Puno ng Mga Paraan ng Mitigasyon

Ang solusyong ito ay gumagamit ng isang integradong estratehiya ng "Control ng Source ng Losses + Pinaigting na Kakayahan ng Pagdala ng Init + Malinaw na Pamamahala ng Kalagayan":

3.1 Optimisasyon at Upgrade ng Cooling System, Pagpapataas ng Epektibidad ng Pagdala ng Init (Tugon sa Pagtaas ng Temperatura)

• Gamitin ang Mataas na Epektibidad na Paraan ng Cooling:
• Forced Air Cooling (OFAF/ODAF): I-retrofit ang umiiral na natural air-cooled (ONAN) o air-forced cooled (ONAF) transformers, o i-equip ang mga bagong yunit ng high-performance axial fans. Piliin ang epektibong, mababang ingay, at weather-resistant fans kasama ang intelligent airflow control (halimbawa, automatic start/stop batay sa temperatura o variable frequency drive adjustment) upang malaki ang pagpapataas ng epektibidad ng air convection sa ibabaw ng radiator at mabilis na alisin ang init.
• Forced Oil Water Cooling (OFWF): Pinapaboran para sa ultra-high-capacity transformers, mga yunit na may mataas na load factors, o ang mga nagsasagawa ng operasyon sa mataas na temperatura ng kapaligiran. I-equip ng high-efficiency oil pumps at plate heat exchangers upang gamitin ang mataas na specific heat capacity ng tubig para sa epektibong heat exchange. Kailangan ng suporta ng water treatment systems (upang maiwasan ang scaling at corrosion) at reliability assurance mechanisms (halimbawa, dual water circuits, standby pumps).
• Heat Pipe Assisted Cooling: Ilagay ang heat pipe modules sa mga critical points sa radiators upang epektibong magpadala at mag-alis ng lokal na hot spot heat sa pamamagitan ng phase-change principle.
• Optimisasyon ng Struktura at Layout ng Radiator:
• Gamitin ang radiators na may dagdag na surface area (halimbawa, finned, panel radiators) at optimized flow path designs.
• Mapanatili ang smooth na flow paths para sa cooling media (air o water), alisin ang mga lokal na flow restrictions, at mapabuti ang uniformity ng pagdala ng init.
• (Para sa air cooling) Optimize ang posisyon ng fan at duct design upang mapanatili ang uniform na coverage ng airflow sa ibabaw ng radiators, minimisihin ang dead zones.
• Intelligent Cooling Control:
• Awtomatikong i-adjust ang output ng cooling system (fan speed/number, oil pump flow rate) batay sa real-time monitoring ng temperatura ng langis, temperatura ng winding, at temperatura ng kapaligiran. Nakakamit ang on-demand cooling, sinisiguro ang epektibidad ng pagdala ng init habang mininimum ang energy consumption ng auxiliary equipment.

3.2 Optimisasyon ng Core Material at Struktura, Pagbawas ng Iron Loss (Core Magnetic Loss Control)

• Piliin ang Mataas na Performance na Core Materials:
• Pinapaboran ang mataas na permeability, mababang unit-loss cold-rolled silicon steel sheets (halimbawa, HiB steel) o mas advanced amorphous alloy materials (na nagbibigay ng malaking benepisyo para sa pagbawas ng no-load loss).
• Matatag na kontrolin ang thickness, flatness, at kalidad ng insulation coating ng silicon steel sheet upang minimisihin ang hysteresis losses at eddy current losses.
• Optimisasyon ng Core Design at Manufacturing Processes:
• I-implement ang step-lap stacking techniques upang minimisihin ang magnetic reluctance sa joints, pagbabawas ng additional iron losses.
• Precisely control core stacking factor and clamping force to ensure uniform magnetic path distribution and avoid local over-saturation.
• (Applying Advanced Technologies) Explore techniques like laser scribing (Laser Scribbling) to further optimize material magnetic domain structure.
• Optimize core grounding methods and shielding to reduce stray losses in structural components.

3.3 Winding Design Optimization and Process Improvement, Reducing Copper Loss (Key Magnetic Loss Control)

• Optimize Winding Structure and Electromagnetic Design:
• Precisely calculate ampere-turn distribution, optimize conductor cross-section shape (e.g., using continuously transposed cables - CTC or self-bonding transposed cables - TTC) to minimize circulating current and eddy current losses.
• Reasonably select conductor material (high-conductivity oxygen-free copper) and current density, effectively reducing DC resistance losses while meeting temperature rise constraints.
• Optimize winding height, diameter, and radial dimensions to control leakage flux and reduce stray losses.
• Advanced Manufacturing Processes:
• Ensure uniform winding compactness using constant-tension winding equipment.
• Employ advanced Vacuum Pressure Impregnation (VPI) or resin casting processes to ensure thorough filling of gaps with insulating materials, improving thermal conductivity and mechanical strength, thereby aiding heat dissipation and reducing partial discharges.

3.4 Magnetic Circuit Condition Monitoring and Proactive Maintenance (Closed-loop Management, Ensuring Long-term Performance)

• Implement Precise Magnetic Circuit Condition Monitoring:
• Comprehensively assess magnetic circuit health by integrating online monitoring (e.g., Dissolved Gas Analysis - DGA, high-frequency partial discharge monitoring, vibration/acoustic noise monitoring, infrared thermography) and offline testing (periodic winding deformation testing, no-load & load loss testing, core ground current testing).
• Focus Monitoring: Signs of core multi-point grounding faults, abnormal loss fluctuations, overheating of magnetic shields and clamping structures.
• Establish a Preventive Maintenance Mechanism:
• Develop targeted magnetic circuit maintenance plans based on condition monitoring data and operational history.
• Periodically inspect core and clamping structure grounding: Ensure reliable single-point grounding, promptly detect and rectify multi-point grounding faults (which significantly increase iron losses and cause overheating).
• Inspect magnetic shields, clamps, and other structural components: Check for looseness, overheating, or discharge traces; promptly eliminate abnormalities.
• During core/lid lifting inspections, conduct focused checks and maintenance on core lamination joints and clamping condition.
• Perform in-depth diagnostic analysis on detected upward trends in abnormal losses to identify root causes and implement corrective actions.

4. Expected Benefits

• Significant Reduction in Temperature Rise: Operating temperatures (especially hotspot temperatures) are expected to be effectively controlled, with reductions reaching projected targets (e.g., 15-25%), greatly alleviating thermal aging stress on insulation.
• Effective Reduction in Magnetic Circuit Losses:
• Iron loss (No-Load Loss): Expected reduction of 20-40% through new materials and processes (especially significant when using amorphous alloys).
• Copper loss (Load Loss): Expected reduction of 10-25% through optimized winding design.
• Overall efficiency improvement of 1-3 percentage points, delivering considerable economic benefits and carbon emission reduction.
• Substantial Improvement in Reliability: Failure risks caused by overheating and magnetic circuit abnormalities are significantly reduced, enhancing equipment availability and extending service life.
• Optimized Total Life Cycle Cost: Despite potentially higher upfront investment (e.g., high-performance materials, advanced cooling systems), the benefits derived from long-term energy savings, reduced maintenance costs, and extended lifespan are more substantial, achieving a favorable Return on Investment (ROI).

5. Applicable Scope

This solution applies to newly built and in-service oil-immersed transmission (power) transformers at 35kV voltage level and above. Specific measures can be customized and implemented based on the transformer's capacity, voltage level, operating environment, criticality, and current condition.