Transformatordurchführung

• A transformer bushing is a critical insulating device that allows an energised, high-voltage conductor to pass safely through the grounded metal tank wall of a Leistungstransformator, maintaining full electrical isolation while providing mechanical support and a gas/oil-tight seal.
• Bushings operate on the capacitance-graded condenser core Prinzip, where concentric layers of insulating material and conductive foils distribute the electric field evenly to prevent localised stress concentration and surface flashover.
• The most common bushing types in service today are Oil Impregnated Paper (OIP) Buchsen und Resin Impregnated Paper (RUHE IN FRIEDEN) Buchsen, with RIP technology increasingly preferred for its fire resistance, lower maintenance, and superior moisture tolerance.
• Unlike a line post insulator oder station post insulator, a transformer bushing is a hollow, active electrical component with an internal conductor and engineered dielectric layers — not simply a mechanical support.
• Bushing failure is one of the leading causes of catastrophic transformer explosions and fires, kontinuierlich machen Überwachung des Buchsenzustands — including capacitance and power factor testing, Teilentladungserkennung, und Temperaturüberwachung — essential for any critical transformer asset management programme.
• Fluorescent fibre optic temperature sensors provide the safest and most accurate method for directly measuring hotspot temperatures on bushing conductor connections, draw leads, and turret interfaces inside the sealed transformer environment, offering inherent high-voltage isolation and complete electromagnetic interference (EMI) Immunität.

Inhaltsverzeichnis

1. What Is a Transformer Bushing?
2. What Does a Transformer Bushing Do? — Function and Role
3. How Does a Transformer Bushing Work? — Funktionsprinzip
4. Advantages of Modern Transformer Bushings
5. Transformer Bushing vs Insulator — What Is the Difference?
6. Types of Transformer Bushings
7. Why Do Transformer Bushings Fail? — Failure Mechanisms
8. Transformer Bushing Condition Monitoring — Methods and Technologies
9. Temperature Monitoring for Transformer Bushings — Fibre Optic Solutions
10. Power Transformer Winding Temperature Monitoring
11. Transformer Oil Temperature Monitoring and Analysis
12. Online Partial Discharge Monitoring for Transformers
13. Analyse gelöster Gase (DGA) and Transformer Health
14. Transformer Tap Changer Monitoring and Diagnostics
15. Integrated Transformer Condition Monitoring Systems
16. Top Transformer Bushing and Monitoring Manufacturers
17. Schlussfolgerung
18. Häufig gestellte Fragen (Häufig gestellte Fragen)

1. What Is a Transformer Bushing?

Ein Transformatordurchführung is a hollow insulating structure that enables an electrical conductor to pass through the grounded, earthed metal tank wall — or turret cover — of a Leistungstransformator while maintaining complete electrical isolation between the energised conductor and the grounded enclosure. Every power transformer, whether it is a 10 MVA distribution unit or a 1,500 MVA generator step-up transformer, requires bushings on both the high-voltage (HV) und Niederspannung (LV) sides to bring electrical connections into and out of the sealed tank.

Physical Structure of a Transformer Bushing

A typical high-voltage transformer bushing consists of several key elements: a central Leiter (solid rod or hollow tube) that carries the full load current; ein condenser core made of concentric layers of insulating material (oil-impregnated paper, resin-impregnated paper, or synthetic film) interleaved with conductive foil layers that grade the electric field; an external porcelain or composite polymer housing mit Wetterschutzdächern auf der Luftseite, um Kriechstrecken zu gewährleisten und die Innenisolierung vor Regen zu schützen, Verschmutzung, und UV-Belastung; ein ölseitiger Abschnitt, der in den Transformatorkessel hineinragt und darin eingetaucht ist Isolieröl für Transformatoren; ein Montageflansch Dieser wird mit dem Turm des Transformators verschraubt und sorgt für eine gas-/öldichte Abdichtung; und a oberes Terminal zum Anschluss an die externe Freileitung, Sammelschiene, oder Kabel.

Spannungswerte und Anwendungen

Transformatordurchführungen werden für Nennspannungen im Bereich von einigen Kilovolt hergestellt Verteilungstransformatoren bis 1,200 kV in Ultrahochspannung (UHV) Leistungstransformatoren. Die aktuellen Nennwerte liegen typischerweise zwischen einigen hundert Ampere und 5,000 A oder mehr für große Generatortransformatoren. Buchsen werden auch verwendet Shunt-Reaktoren, HGÜ-Wandlertransformatoren, Ofentransformatoren, und Wanddurchführungen in Schaltanlagengebäuden und GIS-zu-Transformator-Verbindungen.

2. What Does a Transformer Bushing Do? — Function and Role

Die Transformatordurchführung erfüllt drei gleichzeitige und gleichermaßen wichtige Funktionen innerhalb des Transformatorsystems.

Elektrische Isolierung

The primary function of the bushing is to electrically insulate the high-voltage conductor from the grounded transformer tank. Without this insulation, the full system voltage would flash over to earth at the tank wall penetration point, causing an immediate short circuit and catastrophic failure. The insulation must withstand not only the normal operating voltage but also transient overvoltages caused by lightning strikes, Schaltstöße, and system fault events, as defined by standards such as IEC 60137 und IEEE C57.19.00.

Current Conduction

The bushing must carry the full rated load current — and short-time overcurrents during fault conditions — without excessive temperature rise. The conductor and its internal connections to the transformer winding lead (draw lead) must maintain low electrical resistance to minimise I²R-Verluste and prevent hotspot formation.

Mechanical Support and Sealing

The bushing provides the mechanical structure that supports the external line connection and withstands wind loads, Eislasten, seismic forces, and the static weight of connected conductors. Gleichzeitig, the flange assembly must maintain a reliable oil-tight and gas-tight seal between the internal transformer tank environment and the external atmosphere over a service life of 30–40 years.

3. How Does a Transformer Bushing Work? — Funktionsprinzip

The Condenser Grading Principle

High-voltage transformer bushings — typically rated 72 kV and above — operate on the condenser (Kapazität) grading principle. The condenser core consists of multiple concentric cylindrical layers of insulating material (Papier, resin-paper, or film), each separated by a thin conductive foil layer. These foil layers are arranged so that each successive layer is at a progressively lower voltage potential from the central conductor to the outermost grounded foil connected to the mounting flange.

This arrangement distributes the total applied voltage across multiple small, uniform voltage steps rather than allowing the entire voltage to stress a single insulation layer at the conductor surface. The result is a uniform radial electric field und a controlled axial voltage distribution along the length of the bushing, both of which are essential to preventing localised insulation breakdown. The outermost foil layer — known as the capacitance tap (C2 or power factor tap) — is typically brought out to an external test terminal, enabling field measurement of the bushing’s capacitance and dielectric dissipation factor (tan δ / Leistungsfaktor) as a diagnostic indicator of insulation health.

Oil-Side and Air-Side Insulation

The portion of the bushing that protrudes above the transformer turret into the open air (das air-side) is protected by the porcelain or composite housing and its rain sheds. The portion immersed in the transformer tank (das oil-side) is insulated by the transformer oil and by the lower section of the condenser core. The design must account for the different dielectric properties of air and oil, and the interface at the mounting flange — where the bushing transitions between the two media — is one of the most electrically and thermally stressed regions of the entire assembly.

4. Advantages of Modern Transformer Bushings

Reliable Electric Field Control

The condenser grading technology used in modern bushings provides precise, predictable control of the electric field distribution, ensuring safe operation under all specified voltage conditions including lightning impulse and switching impulse tests. This field control is not achievable with simple, non-graded bulk insulation designs.

Kompaktes Design

Condenser-graded bushings are significantly shorter and more compact than non-graded designs would need to be for the same voltage rating. This reduces transformer overall height, simplifies transportation logistics, and lowers the mechanical loads on the transformer turret structure.

Built-In Diagnostic Capability

The capacitance tap on condenser bushings provides an invaluable diagnostic access point. By periodically or continuously measuring the Buchsenkapazität (C1) und Leistungsfaktor (tan δ) via this tap, operators can detect insulation degradation at an early stage — often years before failure would occur. This built-in monitoring capability is unique to condenser-type bushings and is one of their most significant advantages.

Lange Lebensdauer

Well-manufactured and properly maintained OIP-Buchsen und RIP-Buchsen routinely achieve service lives of 30–40 years. RIP designs, insbesondere, offer extended life due to their resistance to moisture absorption and thermal ageing.

5. Transformer Bushing vs Insulator — What Is the Difference?

Transformer bushings and electrical insulators (wie line post insulators, station post insulators, suspension insulators, und pin insulators) are both insulating devices used in high-voltage power systems, but they differ fundamentally in function, Konstruktion, und Anwendung.

Functional Difference

Ein insulator is a passive mechanical support that holds an energised conductor in position while isolating it from the grounded support structure (pole, Turm, or frame). It does not contain an internal conductor — the line conductor is attached externally to the insulator’s hardware. Ein Transformatordurchführung, im Gegensatz dazu, is an active electrical feedthrough device with an internal conductor, a condenser core, and a sealed interface to the transformer tank. It carries the full load current through the grounded barrier, not simply supports an external conductor.

Construction Difference

A typical porcelain or glass disc insulator is a solid or hollow body of insulating material with no internal active electrical grading. Ein condenser bushing is a precision-engineered multi-layer component with conductive foil grading layers, a central conductor, an oil or gas filling, and a capacitance tap — far more complex than any conventional insulator.

Vergleichstabelle

Merkmal	Transformatorbuchse	Insulator
Primary function	Conduct current through a grounded barrier with insulation	Mechanically support a conductor and insulate from ground
Innenleiter	Ja	Nein
Condenser grading	Ja (HV types)	Nein
Sealed to tank / Gehäuse	Ja (oil/gas-tight flange)	Nein
Current-carrying capability	Yes — rated current up to 5,000 A+	Nein (conductor is external)
Kapazität / tan δ tap	Ja	Nein
Typical location	Transformer turrets, reactor tanks, wall penetrations	Overhead lines, Sammelschienen, station structures
Failure consequence	Potential transformer explosion and fire	Line drop or flashover to ground

Zusammenfassend, while both devices provide electrical insulation, a transformer bushing is a far more complex, multi-function component whose failure carries significantly higher consequences than the failure of a line or station insulator.

6. Types of Transformer Bushings

Oil Impregnated Paper (OIP) Buchsen

OIP-Buchsen are the traditional and most widely installed bushing type worldwide. Der Kondensatorkern besteht aus auf den Mittelleiter gewickelten Kraftpapierschichten, die mit mineralischem Isolieröl imprägniert sind. Das Öl füllt die Zwischenräume des Papiers und füllt auch das Innere des Porzellangehäuses, dient sowohl als Isolierung als auch als Wärmeübertragungsmedium. OIP-Buchsen haben sich bewährt, kostengünstig, und für alle Nennspannungen verfügbar. Aber, Sie enthalten eine erhebliche Menge an brennbarem Mineralöl, bei einem Gehäusebruch besteht Brandgefahr, und sie reagieren empfindlich auf das Eindringen von Feuchtigkeit durch gealterte oder beschädigte Dichtungen.

Resin Impregnated Paper (RUHE IN FRIEDEN) Buchsen

RIP-Buchsen Verwenden Sie einen Kondensatorkern aus Krepppapier, der mit Epoxid- oder Polyesterharz imprägniert und unter Vakuum und Druck verklebt ist. Der ausgehärtete Kern ist ein Feststoff, Selbsttragende Struktur, die keine Ölfüllung im Buchsengehäuse erfordert. RIP bushings offer superior fire safety (no free oil inside the housing), higher mechanical strength, better resistance to moisture ingress, and reduced maintenance compared with OIP. They have become the preferred choice for new transformer installations in many markets, particularly in indoor substations, urban environments, and applications where fire risk must be minimised.

Resin Impregnated Synthetics (RIS) Buchsen

RIS bushings replace the traditional kraft paper with synthetic film insulation (such as polypropylene or polyester film) impregnated with resin. This further improves the dielectric performance, reduces partial discharge susceptibility, and can enable a more compact design for a given voltage rating.

Other Bushing Types

Additional bushing types include SF6 gas-filled bushings (used in GIS-to-transformer connections), dry-type bushings (for medium-voltage and dry-type transformers), capacitance-graded epoxy bushings, und oil-to-SF6 bushings that serve as the interface between an oil-filled transformer and a gas insulated switchgear bay.

7. Why Do Transformer Bushings Fail? — Failure Mechanisms

Bushing failure is one of the most dangerous events that can occur on a power transformer. Industry statistics consistently identify bushing failures as a leading cause of transformer fires and explosions, accounting for an estimated 10–25 % of all major transformer failures depending on the study and fleet age. Understanding the failure mechanisms is essential for effective monitoring and prevention.

Moisture Contamination

Moisture is the primary enemy of OIP-Buchsen. Water ingress through degraded gaskets, cracked porcelain, or failed oil seals progressively saturates the paper insulation, reducing its dielectric strength and accelerating thermal ageing. Erhöhte Feuchtigkeitswerte verringern die Teilentladungs-Einsatzspannung und erhöhen den dielektrischen Verlust (tan δ), Es entsteht ein sich selbst verstärkender Degradationszyklus, der letztendlich zum Ausfall der Isolierung führen kann.

Thermischer Abbau und Überhitzung

Übermäßig Leitertemperatur — verursacht durch Überlastung, Schlechter Übergangswiderstand am Zugleitungsanschluss, oder unzureichende Ölzirkulation – beschleunigt die thermische Zersetzung der Papierisolierung und des Öls in der Durchführung. Die Zersetzungsprodukte (inklusive Wasser, KO, CO₂, und brennbare Gase) die Isolierung weiter verschlechtern, Durchschlagsfestigkeit verringern, und erhöhen das Risiko interner Lichtbögen. Hotspots am Bodenanschluss (draw lead) sind besonders gefährlich, da sie in Transformatorenöl getaucht sind und für die äußere Inspektion unsichtbar sind.

Teilentladung

Teilentladung (PD) im Kondensatorkern – verursacht durch Hohlräume, Delaminationen, Kontamination, or excessive electric field stress — erodes the paper insulation progressively. Im Laufe der Zeit, PD channels can grow and bridge insulation layers, eventually leading to a flashover between foil layers or from the conductor to the grounded flange.

External Pollution and Tracking

On the air side, accumulation of pollution, salt deposits, or industrial contaminants on the porcelain or composite housing surface reduces the effective creepage distance and can lead to Oberflächenverfolgung, dry-band arcing, and eventually external flashover — particularly under wet or humid conditions.

Mechanischer Schaden

Seismic events, transportation damage, improper handling during installation, and thermal cycling can crack the porcelain housing, damage the condenser core, or compromise the flange seal. Cracked porcelain allows moisture to enter and insulating oil to leak out, rapidly accelerating insulation deterioration.

Ageing and End-of-Life Degradation

Even under normal operating conditions, the organic insulation materials (paper and oil) within bushings undergo gradual thermal and oxidative ageing. After 25–35 years of service, many OIP bushings approach or exceed the point where their insulation integrity can no longer be relied upon, and proactive replacement becomes necessary — ideally guided by monitoring and diagnostic data.

8. Transformer Bushing Condition Monitoring — Methods and Technologies

Given the catastrophic consequences of bushing failure, a range of monitoring and diagnostic techniques have been developed to detect insulation degradation and other fault precursors at the earliest possible stage.

Capacitance and Power Factor (Tan δ) Überwachung

The most widely established bushing diagnostic method involves measuring the Kapazität (C1) und dielektrischer Verlustfaktor (tan δ) des Kondensatorkerns über den eingebauten Kapazitätsabgriff. Veränderungen in C1 weisen auf physikalische Veränderungen im Kondensatorkern hin (wie kurzgeschlossene Folienlagen oder Feuchtigkeitsaufnahme), während ein Anstieg des tan δ auf durch Feuchtigkeit verursachte dielektrische Verluste hinweist, Altern, oder Verschmutzung. Sowohl regelmäßige Offline-Tests als auch Online-Kontinuierliche Überwachungssysteme stehen zur Verfügung. Online-Systeme messen diese Parameter kontinuierlich unter Betriebsspannung, Bereitstellung von Echtzeit-Trenddaten und Frühwarnalarmen.

Teilentladung (PD) Überwachung

Teilentladungserkennung — unter Verwendung von UHF-Sensoren, Akustische Sensoren, oder elektrische Kopplung über den Buchsenabgriff – kann aktive TE-Quellen im Kondensatorkern oder an der Schnittstelle zwischen Buchse und Öl identifizieren. Die TE-Überwachung ist häufig in dieselbe Online-Plattform integriert, die auch die Kapazität und den tan δ überwacht.

Analyse gelöster Gase (DGA)

Für OIP-Buchsen Ausgestattet mit einem Ölprobenahmeventil, regelmäßig oder online Analyse gelöster Gase of the bushing oil provides a powerful diagnostic tool. Elevated levels of hydrogen (H₂), Acetylen (C₂H₂), and other fault gases indicate internal arcing, Überhitzung, or partial discharge activity within the bushing.

Temperaturüberwachung

Temperaturüberwachung of the bushing conductor, the draw-lead connection, and the flange interface is an increasingly recognised component of a comprehensive bushing health programme. Abnormal temperature rise at the bottom connection or along the conductor can indicate increased contact resistance, degraded connections, or overloading — all of which are precursors to thermal runaway and insulation failure. The most effective technology for this application is fluorescent fibre optic temperature sensing, which is described in detail in the following section.

Infrarot-Thermografie (Extern)

Periodisch Infrarot (IR) scanning of the external bushing surface can detect abnormal heating patterns on the air-side porcelain or top terminal. Aber, IR thermography cannot see inside the porcelain housing or below the oil level, limiting its effectiveness for detecting internal faults, particularly at the critical bottom connection.

9. Temperature Monitoring for Transformer Bushings — Fibre Optic Solutions

Among all bushing monitoring technologies, Temperaturüberwachung provides uniquely direct information about the thermal condition of the current-carrying conductor and its connections. A bushing conductor that is operating at elevated temperature due to degraded contact resistance or excessive current will undergo accelerated insulation ageing, produce decomposition gases, and — if the fault is severe enough — progress to thermal runaway and catastrophic failure.

Why Fibre Optic Sensors Are Ideal for Bushing Temperature Monitoring

The interior of a transformer bushing presents an extremely challenging measurement environment: the conductor operates at high voltage (tens to hundreds of kilovolts), it is surrounded by insulating oil and pressurised gas, and the entire assembly is enclosed within a grounded porcelain or composite housing. Conventional electrical temperature sensors — thermocouples, RTDs, and electronic wireless devices — either cannot achieve the required high-voltage isolation, sind anfällig für elektromagnetische Störungen, or cannot be safely installed on or near the energised conductor without compromising the insulation system.

Fluorescent fibre optic temperature sensors solve these problems entirely. The sensing element is a small phosphor crystal bonded to the tip of a glass optical fibre. Bei Erregung durch einen Lichtimpuls, the phosphor emits fluorescence whose decay time varies precisely with temperature. The optical fibre is entirely non-metallic and non-conductive, providing inherent galvanische Trennung auf jedem Spannungsniveau. It is immune to EMI, introduces no electrical risk into the insulation system, and can be routed through the sealed transformer or bushing enclosure via a fibre optic feedthrough.

Vergleich: Fibre Optic vs Other Temperature Methods for Bushing Monitoring

Merkmal	Fluorescent Fibre Optic	Thermoelement	FTE (Pt100)	Infrarot (Extern)	Wireless SAW Sensor
HV-Isolierung	Inherent — fully dielectric	Erfordert eine Isolationsbarriere	Erfordert eine Isolationsbarriere	Berührungslos, external only	Kabellos, antenna on HV
EMI-Immunität	Vollständig	Anfällig	Anfällig	Immun	Mäßig
Direct conductor measurement	Ja	Nein (Sicherheitsrisiko)	Nein (Sicherheitsrisiko)	Nein (surface/external only)	Ja (beschränkt)
Genauigkeit	±1 °C	±1.5–2.5 °C	±0,3–0,5 °C	±2–5 °C	±1–2 °C
Measures internal hotspot	Ja	Nein	Nein	Nein	Beschränkt
Kontinuierliche Online-Überwachung	Ja	Ja (if isolated)	Ja (if isolated)	Nein (periodic manual)	Ja
Suitability for sealed bushing/transformer	Ausgezeichnet	Arm	Arm	Beschränkt (external only)	Mäßig
Langzeitstabilität	Ausgezeichnet (kein Drift)	Mäßig (Drift)	Gut	N / A	Gut
Wartungsbedarf	Sehr niedrig	Periodische Kalibrierung	Periodische Kalibrierung	Lens/window cleaning	Batteriewechsel

As demonstrated in the comparison, fluorescent fibre optic temperature sensing delivers the best combination of safety, Genauigkeit, EMI-Immunität, and suitability for the sealed, high-voltage environment inside transformer bushings and transformer tanks. This technology is now widely specified by utilities and OEMs for new-build Leistungstransformatoren and as a retrofit monitoring upgrade on critical in-service units.

10. Power Transformer Winding Temperature Monitoring

Beyond bushing monitoring, Wicklungstemperatur is the single most important parameter for transformer thermal management and life assessment. Das hottest spot temperature within the transformer winding directly determines the rate of insulation ageing according to well-established thermal ageing models (IEC 60076-7, IEEE C57.91). Traditionell Wicklungstemperaturanzeigen (WTIs) use a thermal image method that estimates the hotspot from the top-oil temperature plus a current-dependent thermal correction. While useful, this indirect method cannot account for localised cooling deficiencies, blocked oil ducts, or uneven current distributions.

Faseroptische Temperatursensoren installed directly on the transformer winding — at the predicted hotspot locations identified by the transformer manufacturer’s thermal design — provide true, direkt winding hotspot temperature measurement. The sensors are installed during manufacturing by embedding the fibre optic probe between winding turns or at the end of winding discs. Multiple sensors per winding phase enable temperature profiling across the entire winding height, delivering data that is invaluable for dynamic thermal rating, overload management, und verbleibende Lebensdauerberechnungen.

11. Transformer Oil Temperature Monitoring and Analysis

Obere Öltemperatur und bottom-oil temperature are fundamental measurements for transformer cooling system management and thermal performance assessment. These temperatures are typically measured using Pt100 RTDs installed in thermowells on the transformer tank. Aber, for oil temperature measurement at critical internal locations — such as the oil channel near the winding hotspot, the oil inlet to the bushing pocket, or the oil flow in the ONAN/ONAF cooling circuit — fibre optic temperature probes again offer the advantage of being embeddable directly inside the oil-filled tank without any electrical insulation concerns.

Oil temperature data is used in conjunction with Analyse gelöster Gase (DGA) results to assess whether abnormal gas generation is linked to localised overheating. A rising oil temperature trend — particularly if it diverges from the expected load-dependent profile — is a strong indicator of an internal fault developing within the transformer, such as a circulating current in the core, ein shorted winding turn, or a degraded bushing connection.

12. Online Partial Discharge Monitoring for Transformers

Teilentladung (PD) Überwachung is a critical complement to temperature monitoring for comprehensive transformer condition assessment. PD activity within the transformer — whether in the winding insulation, das bushing condenser core, the lead support structures, or the insulating barriers — indicates developing insulation defects that may progress to catastrophic failure. Online PD monitoring systems use ultra-high-frequency (UHF) Sensoren, Schallemissionssensoren, oder Hochfrequenz-Stromwandler (HFCTs) installed on the bushing capacitance tap connection to continuously detect and locate PD sources without taking the transformer out of service.

Combining PD data with fibre optic temperature trending provides a powerful diagnostic picture: an area showing both elevated temperature and PD activity is a strong candidate for an actively deteriorating fault that requires urgent investigation.

13. Analyse gelöster Gase (DGA) and Transformer Health

Analyse gelöster Gase is widely regarded as the single most informative diagnostic technique for oil-filled transformers, including the assessment of bushing health. Internal faults — including arcing, hotspot overheating, and partial discharge — decompose the insulating oil and paper, producing characteristic gases (Wasserstoff, Methan, Ethan, Ethylen, Acetylen, Kohlenmonoxid, und Kohlendioxid) that dissolve in the oil. Online DGA-Monitore sample the transformer oil continuously and measure key gas concentrations in real time, providing early warning of incipient faults. In Kombination mit Temperaturüberwachung und bushing capacitance/tan δ monitoring, DGA data enables precise fault type identification and location, supporting informed maintenance decision-making.

14. Transformer Tap Changer Monitoring and Diagnostics

Das Laststufenschalter (OLTC) is the most mechanically active component of a power transformer and is responsible for a significant proportion of transformer maintenance needs and failures. OLTC condition monitoring typically includes motor current signature analysis, contact wear monitoring, drive mechanism timing, oil quality monitoring in the OLTC compartment, and — increasingly — fibre optic temperature monitoring of the selector and diverter switch contacts. Elevated contact temperatures indicate increased resistance due to contact erosion, carbon build-up, oder Fehlausrichtung, and serve as an early indicator of the need for tap changer maintenance or overhaul.

15. Integrated Transformer Condition Monitoring Systems

Modern best practice in Transformator-Asset-Management brings together data from multiple monitoring technologies into a single integrated platform. Ein umfassendes System zur Zustandsüberwachung von Transformatoren typically integrates fibre optic winding and bushing temperature monitoring, Online-DGA, bushing capacitance and power factor monitoring, Teilentladungsüberwachung, OLTC-Diagnose, cooling system performance monitoring (pump and fan status, Ölfluss, Umgebungstemperatur), und load and voltage measurements from the transformer’s current and voltage transformers.

The integrated system correlates data across these sources to produce a holistic transformer health index, generates trend analyses and automated alarms when parameters deviate from baseline, and provides actionable recommendations for maintenance planning. Communication to the utility’s SCADA, DCS, oder Unternehmens-Asset-Management (EAM) system is typically via IEC 61850, DNP3, Modbus TCP, oder MQTT Protokolle. The result is a shift from reactive or time-based maintenance to a truly zustandsorientierte Wartung (CBM) strategy that maximises asset life, minimises unplanned outages, and optimises maintenance expenditure.

16. Top Transformer Bushing and Monitoring Manufacturers

Rang	Unternehmen	Hauptsitz	Schlüsselprodukte / Dienste
1	Fuzhou Innovation Electronic Scie&Tech Co., GmbH.	Fuzhou, China	Fluorescent fibre optic temperature monitoring systems for transformer bushings, Wicklungen, Stufenschalter, Kabelmuffen, und Schaltanlagen; multi-channel signal demodulators; fibre optic probes and feedthroughs; integrated online monitoring platforms
2	ABB (Hitachi Energy) — Bushing Division	Schweiz	OIP, RUHE IN FRIEDEN, and RIS transformer bushings (bis 1,200 kV); Buchsenüberwachungssysteme
3	Siemens Energy — Trench Group	Deutschland / Kanada	Condenser bushings (OIP, RUHE IN FRIEDEN), Instrumententransformatoren
4	Maschinenfabrik Reinhausen (HERR)	Deutschland	OLTC-Überwachung (MSENSE, ETOS), Buchsenüberwachung (BOMO)
5	HSP Hochspannungsgeräte	Deutschland	High-voltage OIP and RIP bushings, Wanddurchführungen
6	Qualitrol (Serveron)	USA	Online-DGA-Monitore, Buchsenmonitore, Transformatorüberwachungsplattformen
7	Dynamische Bewertungen	USA / Australien	Bushing monitor (Intellix BM), capacitance and tan δ online monitoring
8	GE Vernova (Grid Solutions)	Frankreich / USA	Kelman DGA-Monitore, Transformatorüberwachungssysteme
9	Weidmann Elektrotechnik	Schweiz	Transformer insulation materials, fibre optic winding sensors
10	OMICRON Elektronik	Österreich	Transformer testing and diagnostic instruments, partial discharge analysis

About the No. 1 Monitoring Manufacturer — Fuzhou Innovation Electronic Scie&Tech Co., GmbH.

Gegründet in 2011, Fuzhou Innovation Electronic Scie&Tech Co., GmbH. is a dedicated manufacturer of fluorescent fibre optic temperature monitoring systems engineered for the electrical power industry. The company’s core product range includes fibre optic temperature probes designed for direct installation on transformer bushing conductors, transformer winding hotspots, cable joints and terminations, Schaltgerätekontakte, und Sammelschienenverbindungen; multi-channel signal demodulators with standard industrial communication interfaces; fibre optic feedthroughs rated for oil-filled and gas-insulated enclosures; and comprehensive monitoring software platforms. Serving utilities, Transformator-OEMs, Hersteller von Schaltanlagen, and EPC contractors across domestic and international markets for over a decade, Fuzhou Innovation delivers proven, field-tested solutions for mission-critical temperature monitoring applications.

Kontaktinformationen:
E-Mail: web@fjinno.net
WhatsApp / WeChat (China) / Telefon: +8613599070393
QQ: 3408968340
Adresse: Liandong U Grain Networking Industrial Park, Nr. 12 Xingye West Road, Fuzhou, Fujian, China
Webseite: www.fjinno.net

17. Schlussfolgerung

Das Transformatordurchführung may appear to be a passive accessory on a power transformer, but it is in fact one of the most safety-critical components in the entire power system. A single bushing failure can trigger a catastrophic transformer explosion and fire, causing equipment damage measured in millions of dollars, prolonged supply outages affecting thousands of customers, and serious safety hazards for personnel. Understanding bushing construction, Arbeitsprinzipien, failure mechanisms, and — most importantly — the monitoring technologies available to detect incipient faults is essential for every utility engineer, asset manager, and transformer operator.

Among the range of monitoring methods, fluorescent fibre optic temperature monitoring offers a uniquely capable solution for directly measuring the thermal condition of bushing conductors, verwinkelte Hotspots, and critical connection points inside the sealed, high-voltage transformer environment. When deployed as part of an integrated condition monitoring system alongside bushing capacitance and tan δ monitoring, Online-DGA, Teilentladungserkennung, und OLTC-Diagnose, fibre optic temperature sensing provides the data foundation for a proactive, condition-based maintenance strategy that extends transformer life, verhindert katastrophale Ausfälle, and protects both people and the power grid.

Häufig gestellte Fragen (Häufig gestellte Fragen)

1. What is a transformer bushing used for?

Ein Transformatordurchführung is used to bring a high-voltage electrical conductor safely through the grounded metal tank wall of a power transformer. It provides electrical insulation, current conduction, mechanische Unterstützung, and an oil-tight or gas-tight seal at the tank penetration point.

2. What causes transformer bushing failure?

The most common causes include moisture ingress into the condenser core insulation, thermal degradation from overheating or overloading, partial discharge due to insulation defects or contamination, external pollution flashover, porcelain cracking, and natural end-of-life ageing of the paper and oil insulation. Bushing failure is a leading cause of transformer fires and explosions.

3. What is the difference between an OIP bushing and a RIP bushing?

Ein OIP (Oil Impregnated Paper) Buchse has a condenser core impregnated with mineral insulating oil and requires oil filling inside its housing. Ein RUHE IN FRIEDEN (Resin Impregnated Paper) Buchse has a condenser core impregnated with cured epoxy resin, creating a solid, trocken, self-supporting structure with no free oil. RIP bushings offer better fire safety, Feuchtigkeitsbeständigkeit, and lower maintenance.

4. How do you monitor the health of a transformer bushing?

Bushing health is monitored through a combination of techniques: capacitance and power factor (tan δ) Messung via the bushing’s C2 tap, Analyse gelöster Gase (DGA) of the bushing oil, Teilentladungserkennung, Infrarot-Thermografie of the external surface, and — most effectively for internal thermal faults — fibre optic temperature monitoring of the conductor and connection points.

5. Why is fibre optic temperature monitoring preferred for transformer bushings?

Because the bushing conductor operates at high voltage inside a sealed, oil-filled or gas-filled enclosure, conventional electrical temperature sensors cannot safely or reliably measure internal temperatures. Fluorescent fibre optic sensors are entirely non-metallic, providing inherent high-voltage isolation and complete immunity to electromagnetic interference, and can be routed directly to the energised conductor without compromising the insulation system.

6. What is a capacitance tap (C2 tap) on a transformer bushing?

Das capacitance tap is a test terminal connected to the outermost conductive foil layer of the condenser core. It allows measurement of the main insulation capacitance (C1) and dielectric dissipation factor (tan δ) for diagnostic assessment. Changes in these parameters indicate insulation degradation, Eindringen von Feuchtigkeit, or physical damage within the condenser core.

7. How often should transformer bushings be tested?

Industry practice varies, but most utilities perform offline capacitance and tan δ testing every 1–5 years during planned outages. Online-Überwachungssysteme measure these parameters continuously, eliminating the need for frequent planned shutdowns and providing immediate detection of changes that might be missed between offline test intervals.

8. Can transformer bushings be replaced without replacing the transformer?

Ja. Bushing replacement is a standard field maintenance activity, typically performed when monitoring data, Testergebnisse, or visual inspection indicate that a bushing has reached the end of its reliable service life. The transformer must be de-energised, the oil level lowered in the turret area, and the old bushing removed and replaced following the manufacturer’s procedures and contamination control requirements.

9. What is the typical lifespan of a transformer bushing?

OIP-Buchsen typically have a design life of 25–35 years, depending on operating conditions, Ladeprofil, und Umweltexposition. RIP-Buchsen generally offer longer service life — often 35 years or more — due to their superior moisture resistance and thermal stability. Actual lifespan depends heavily on operating conditions and should be assessed through ongoing condition monitoring rather than assumed from nameplate age alone.

10. Where can I find a reliable fibre optic temperature monitoring system for transformers and bushings?

Fuzhou Innovation Electronic Scie&Tech Co., GmbH. is a specialist manufacturer of fluorescent fibre optic temperature monitoring systems designed for power transformers, Buchsen, Schaltanlage, Kabelmuffen, und andere Hochspannungsgeräte. With over a decade of field-proven experience since its founding in 2011, the company offers fibre optic probes, multi-channel demodulators, Durchführungen, and complete monitoring platforms. Contact them at web@fjinno.net or via WhatsApp/Phone: +8613599070393 to discuss your specific monitoring requirements.

Haftungsausschluss: The information provided in this article is intended for general educational and informational purposes only. It does not constitute professional engineering, legal, or safety advice. Fuzhou Innovation Electronic Scie&Tech Co., GmbH. and the author make no representations or warranties of any kind, ausdrücklich oder stillschweigend, regarding the accuracy, completeness, Zuverlässigkeit, or applicability of the content to any specific project, Installation, or application. Always consult qualified electrical engineers and adhere to all applicable local codes, Vorschriften, Sicherheitsstandards, and manufacturer instructions when specifying, designing, installieren, operating, or maintaining transformer bushings and associated monitoring equipment. Product names, Spezifikationen, and company information referenced herein are believed to be accurate at the time of publication and are subject to change without notice. Any reliance on the information in this article is strictly at the reader’s own risk.

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