Early Exploration (1920s–1950s) – Primitive Protection 1922: Early trolley wire greasing was documented in Scientific American, focusing on reducing friction for rail catenary systems. 1927: The U.S. first applied petroleum jelly (Vaseline) to conductor joints for basic anti-corrosion. Europe and Japan followed, using asphalt mixtures, lanolin blends, and simple soap-based greases as early protective materials. Limitations: Low melting point (~50–70°C), easy dripping in heat, poor water resistance, short protection life. Core goal: Stop surface rust on steel cores and aluminum strands in early transmission lines.
Industrialization & Widespread Use (1960s–1980s) – Specialized Formulation Driven by industrialization and coastal/heavy-industry grid expansion, greased stranded conductors became standard in Europe, North America, and South America. Formulations evolved: Shifted from simple petroleum jelly to hydrocarbon-based greases, metal soap-thickened greases (calcium/lithium soap). Added anti-oxidants, rust inhibitors, and water-repellent additives. Key functions expanded: Anti-corrosion + inter-strand lubrication to reduce aeolian vibration wear. Waterproof sealing to block moisture penetration into stranded cores. Application methods: Hot-applied greasing during conductor manufacturing (better filling and adhesion). Cold-applied for retrofitting existing lines. Impact: Extended ACSR service life from ~20 years to 30+ years.
Standardization Era (1990s–2010s) – Global Technical Norms 1997: IEC published IEC 61394:1997 – the first international standard for overhead conductor greases, defining performance, testing, and classification. 2002: CENELEC released EN 50326:2002, widely adopted in Europe, classifying greases into Type A (cold-applied) and Type B (hot-applied). Regional standards emerged: ENA ER L38 (UK), Japanese JIS standards, and early Chinese industry guidelines. Technical upgrades: High-temperature stability (no oil separation at 100–150°C). Low-temperature flexibility (no cracking at −40°C). Compatibility with aluminum, steel, and line hardware. UV resistance and long-term aging stability.
Modern High-Performance & China’s Standardization (2010s–Present) Global trends: Synthetic oil-based greases (PAO, ester) for extreme environments (high-altitude, polar, coastal). Nano-additives for better adhesion and anti-corrosion. Environmentally friendly, low-drip, and non-toxic formulations. China’s breakthrough: Before 2018: No national standard; quality varied widely (dripping, poor water resistance). 2018: Issued GB/T 36292-2018 and T/CEC 158-2018, unifying technical requirements and boosting domestic product quality. Current status: Greased conductors are mandatory in coastal, industrial, and high-corrosion zones worldwide. Combined with corrosion-resistant alloys and coatings for multi-layer protection.
