نظارت بر بوش ترانسفورماتور و ترکیب سیستم, راهنمای نهایی 2025 نسخه

Transformer bushing monitoring focuses on the bushing’s insulation and sealing health under live conditions. It continuously tracks leakage current phasors, از دست دادن دی الکتریک (tanδ), capacitance C1/C2, هارمونیک ها (with emphasis on 3rd harmonic), تخلیه جزئی (PD) via IEC 60270/UHF/آکوستیک, دما (preferably دمای فیبر نوری فلورسنت, FOT), as well as oil level/pressure/moisture activity یا SF6/N2 density, و Test Tap/C2 grounding continuity. A well-implemented transformer bushing monitoring system gives early warning of insulation deterioration, ورود رطوبت, sealing degradation, and hotspot formation, reducing the risk of forced outages and fires.

Scope includes OIP/RIP/RIS/SF6 bushings, covering the Test Tap/C2, top connection, flange transition, external insulation surface, and sealing interfaces. Typical outputs are graded alarms, الف health index (HI), event timelines, and maintenance recommendations integrated with SCADA/APM تمام IEC 61850 MMS/GOOSE.

Why Transformer Bushings Need Monitoring

Safety and reliability

خرابی بوش are low-frequency but high-consequence events that can lead to explosions, oil spray, and fires. Online observability shortens time-to-detection and prevents cascading damage.

Aging, محیط زیست, and stress

Factors include aging OIP کاغذ, high humidity, آلودگی, salt mist, thermal cycling, through-faults, short overvoltages, and harmonic stress, all of which accelerate insulation and sealing degradation reflected in tanδ, C1/C2, PD, and temperature trends.

هزینه, انطباق, and evidence

Online data reduces disruptive offline tests, supports compliance and insurance evidence chains, and enables risk-based maintenance and spares planning.

How Transformer Bushing Failures Happen

Typical mechanisms include: (1) Insulation aging/moisture raising tanδ and drifting C1/C2, with PD onset; (2) Grading imbalance concentrating electric field near foils/edges; (3) Poor joints at the top connection increasing contact resistance and hotspots; (4) Surface contamination/flashover driving higher leakage currents in wet weather; (5) Seal degradation causing oil/gas leakage, water activity rise, and lower dielectric strength; (6) Through-fault latent damage introducing micro-voids and interface defects. Each maps to online observables: leakage-current phasors, tanδ, C1/C2 رانش, 3rd harmonic ratio, PD الگوهای PRPD, و دما residuals.

One Failure Type: Hotspots

Hotspots often occur at the top conductor-joint interface, the flange transition, the OIP top-oil region, grading foil ends, و Test Tap تماس بگیرید. Causes include elevated contact resistance, eddy/skin losses, local field distortion, and impaired oil circulation. Online indicators are rising FOT temperatures and phase-to-phase temperature deltas, shifts in leakage-current فاز, increased 3rd harmonic, و PD phase clustering. These signatures help distinguish thermal defects from purely dielectric issues and guide targeted inspections.

What Transformer Conditions Does Bushing Monitoring Indicate Most Clearly?

Bushing monitoring most clearly flags: (1) Moisture ingress and rising از دست دادن دی الکتریک (tanδ); (2) Capacitance C1/C2 drift from grading imbalance; (3) PD onset and activity growth via PRPD; (4) Hotspot formation and thermal run-away risk via FOT residuals; (5) Seal degradation via oil level/pressure and SF6 density trends; (6) Test Tap grounding anomalies observed in leakage-current vectors. Together, these provide high-confidence, multi-evidence early warning.

Asset Management: Trending, Decisions, and Outage Avoidance

Asset managers can assess bushing failure risk over time, then install a سیستم مانیتورینگ بوشینگ to act before unplanned outages. Best practice: establish a commissioning baseline and temperature/load compensations; trend tanδ/C drift rates, PD activity, FOT residuals; compute a health index (HI) with graded alarms; and run a closed loop of remote validation → targeted offline tests (tanδ/C/PD) → derating/repair/replacement → threshold tuning. KPIs include detection rate, false alarm rate, avoided outages, and ROI/payback.

What Is Transformer Bushing Monitoring?

Transformer bushing monitoring is an integrated, always-on solution combining sensors, acquisition, time sync, communications, تجزیه و تحلیل, and cybersecurity to assess bushing health live.

System composition

• حسگرها: leakage current via Test Tap/C2, tanδ/C1/C2 online module, PD (IEC 60270/UHF/آکوستیک), FOT دما, oil level/pressure/moisture یا SF6/N2 density, Test Tap grounding continuity.
• Acquisition & sync: multi-rate ADC, line-frequency sync for phasors/harmonics, high-speed PD channel, unified timestamps via GPS/PTP, edge feature extraction و change-point detection.
• ارتباطات & platform: IEC 61850 MMS/GOOSE (with DNP3/Modbus/MQTT as needed), روندها, phasor vectors, PRPD, HI, and work-order integration with SCADA/APM.
• امنیت & عملیات: IEC 62351, network zoning, certificates, audit, periodic self-check/calibration, firmware lifecycle.

Where Do Transformer Bushing Hotspot Failures Occur?

Typical locations: (1) top conductor-to-stud joint; (2) flange/grounding band transition; (3) OIP top-oil region; (4) grading-foil ends and lead-outs; (5) Test Tap contact/ground; (6) external insulation areas prone to contamination.

Root Causes Requiring Bushing Monitoring

Risk drivers

High-consequence failures, aging fleets, extreme weather, آلودگی, and increased grid stress all elevate bushing risk.

Technical drivers

Online sensitivity to tanδ/C/PD/FOT changes exceeds periodic inspections; multi-signal fusion reduces uncertainty; cross-link to DGA/OLTC/cooling data enhances diagnostics.

Economic drivers

Fewer forced outages, optimized spares and maintenance windows, higher insurance and compliance confidence.

Methods to Measure Transformer Bushing Hotspot Temperature

Fiber-Optic Sensing: FOT, DTS/DAS, FBG

دمای فیبر نوری فلورسنت (FOT): uses fluorescence lifetime decay versus temperature, تحویل دادن absolute temperature, with excellent ایمنی EMI and electrical isolation. Ideal for multi-point placement at the flange, top connection, and OIP top-oil region.

Distributed fiber (DTS/DAS): uses Raman/Rayleigh backscatter for continuous or quasi-continuous profiles along the fiber, enabling area coverage and hotspot localization over long runs.

گریتینگ فیبر براگ (FBG): measures Bragg wavelength shift with temperature/strain; requires careful strain decoupling for accurate temperature readings in vibrating/expanding structures.

Installation and routing essentials

Keep fibers short and straight, respect minimum bend radius, avoid sharp edges/moving parts, ensure robust mechanical fixation and good thermal coupling, and plan jumper redundancy and protected routing near high-field zones.

Fiber method	اصل	Typical placement	مزایا	محدودیت ها	Suitability
FOT (فلورسنت)	Fluorescence lifetime vs. دما (absolute)	Flange ring, top joint, OIP top-oil multi-points	ایمنی EMI, electrical isolation, absolute temp, پاسخ سریع, low drift	Requires interrogator; disciplined fiber routing	بهترین for high-field near-bushing areas
DTS/DAS	Raman/Rayleigh distributed backscatter	Perimeter/lead routing for area coverage	Line/area coverage, hotspot localization	Resolution/rate limits, higher system cost	Good for area scanning and surveys
FBG	تغییر طول موج براگ (temp/strain)	سنسورهای نقطه ای; requires strain decoupling	دقت بالا, multiplexing	Strain cross-sensitivity, complex decoupling	متوسط; suited when decoupling is ensured

دمای بی سیم

Passive/active wireless nodes can reduce wiring and simplify installation. با این حال, in high-field bushing vicinities, metallic parts and strong EM fields challenge energy harvesting, ثبات, and insulation safety. Use primarily in shielded compartments or secondary boxes away from the highest fields.

ترموگرافی مادون قرمز

Handheld or fixed IR cameras provide بدون تماس scans and intuitive thermograms. They are affected by emissivity, باد, باران, and solar loading, cannot see through shields/enclosures, and are less sensitive to enclosed joint hotspots. Best for patrols and rapid screening, plus post-alarm verification.

آرسنید گالیوم (GaAs) دما

GaAs optical probes measure band-edge shifts vs. دما, ارائه دقت بالا, عایق, و EMI robustness. Costs and packaging/thermal-coupling practices are higher; use as a complement for selected critical points.

Which Method Is Most Suitable for Bushing Temperature Monitoring?

For live high-field bushing regions, fiber optics are the most robust. به طور خاص, FOT offers the best combination of electrical isolation, ایمنی EMI, absolute temperature, multi-point scalability, fast dynamics, and low drift. A practical blend is FOT for point hotspots plus DTS for area sweeps; IR supports quick visual checks; wireless/FBG/GaAs add value at selected locations.

Fiber-Optic Reliability Over Decades; FOT Is the Best Fit

Decades of field use show fiber-optic sensing avoids parasitic loops and common-mode interference, introduces no conductive paths near HV parts, and maintains stability under severe EMI. FOT excels for near-bushing hotspots due to absolute metrology and minimal drift, enabling confident correlation with leakage-current phasors, tanδ/C1/C2 رانش, و PD signatures for root-cause isolation.

What Sensors Are in Transformer Monitoring?

مانیتورینگ بوشینگ

Leakage current (via Test Tap/C2), tanδ/C1/C2, 3rd harmonic, تخلیه جزئی (IEC 60270/UHF/آکوستیک), FOT دما, oil level/pressure/moisture activity, SF6/N2 density, Test Tap grounding.

Temperature/Cooling Control

Winding hotspot estimates, دمای روغن, radiator inlet/outlet temps, fan/pump status, thermal efficiency, and redundancy control.

OLTC Monitoring

Transition resistance, switching time/waveform, vibration and temperature rise, contact wear diagnostics.

تجزیه و تحلیل گازهای محلول (DGA)

Key gases (H2, CH4, C2H2, و غیره), moisture and oil quality for main-tank insulation condition.

Moisture Monitoring

روغن water activity/ppm and cellulose moisture estimation.

نظارت بر تخلیه جزئی

IEC 60270 current method, UHF, and acoustic/ultrasonic with PRPD pattern analysis.

Through Faults

Fault-current shocks, thermal-mechanical stress logs, and fast post-event health checks (tanδ/C/PD/temperature re-tests).

سنسور دمای فیبر نوری, سیستم مانیتورینگ هوشمند, تولید کننده فیبر نوری توزیع شده در چین