What is «partial discharge» in cables?
Partial Discharge (PD) is a localized dielectric breakdown that occurs within a small portion of a electrical cable’s insulation system under high-voltage stress. Unlike a complete breakdown, PD does not completely bridge the space between the primary Conductor and the outer ground shield/metallic Armor. According to the international standard IEC 60270, PD occurs when the […]
What are the specifications for the order and number of positive and negative polarities applied in the impulse withstand voltage test of high-voltage cables? How to locate the fault point and analyze the cause of failure after a breakdown test?
High-Voltage Cable Impulse Withstand Voltage Test Specifications According to international standards IEC 60840 (for cables rated up to 150 kV and IEC 62067 (for cables rated above 150 kV up to 500 kV, the lightning impulse withstand voltage test must be conducted at a controlled elevated temperature—specifically with the cable conductor maintained between 90°C and 95°C (or the […]
In what scenarios are single-core cables and multi-core cables used respectively?
Single-Core vs. Multi-Core Cables: Primary Application Zones Single-core and multi-core cables are selected based on the structural constraints of the electrical network, specifically current-carrying capacity (ampacity), mechanical stress, and space availability. Single-core cables are primarily deployed in high-power, utility-scale transmission and heavy industrial distribution networks where high ampacity and large conductor cross-sections (typically above 300 […]
What are the core differences between the three power cable standards BS 5467, IEC 60502, and GB/T 12706 in terms of conductor structure, insulation thickness, and sheath mechanical properties?
Core Technical Differences: BS 5467, IEC 60502, and GB/T 12706 The core variance among BS 5467, IEC 60502-1, and GB/T 12706.1 lies in structural dimensional margins, design intents, and region-specific mechanical tolerances. While IEC 60502 acts as the harmonized international parent standard establishing minimum baseline parameters, GB/T 12706 is its Chinese national equivalent, modified to […]
What do the letters and numbers on a cable model number represent?
The alphanumeric codes printed on cable jackets are not arbitrary markings. They represent a highly standardized coding system that defines a cable’s physical structure, material composition, rated performance, and application suitability. Whether referencing global standards such as IEC 60502, Germany’s VDE 0276, or national GB standards, the underlying nomenclature logic remains consistent. Understanding this structural […]
According to GB/T 2952, what are the applicable laying environments for armored cables with galvanized steel strip and stainless steel strip armor, and how are their corrosion resistance levels classified?
GB/T 2952 Protective Layers for Armored Cables: Application & Corrosion Resistance Under the GB/T 2952 standard (Protective layers of electric cables), armored cables with Galvanized Steel Strip (GSS) and Stainless Steel Strip (SSS) are categorized by their ability to withstand mechanical stress and environmental chemical aggression. Galvanized steel strip armor is the industry standard for […]
How to Distinguish Between High-Voltage and Low-Voltage Cables? Where Are They Used in Daily Life?
The primary differences between High-Voltage (HV) cables and Low-Voltage (LV) cables lie in their insulation structure and rated voltage (\(U_0/U\)). According to the IEC 60038 and IEC 60502 standards, low-voltage cables typically operate within the range of 0.6/1kV, using simple-structured Polyvinyl Chloride (PVC) or Cross-Linked Polyethylene (XLPE) insulation. In contrast, high-voltage cables (typically graded from […]
What are the criteria for determining water tree aging and electrical tree aging in old cable lines?
Criteria for Determining Water Tree and Electrical Tree Aging Aging in Medium and High Voltage (MV/HV) XLPE cables is primarily assessed through the detection of Water Trees and Electrical Trees, which represent distinct degradation phases. Water treeing is a pre-breakdown phenomenon occurring in the presence of moisture and an electric field, characterized by microscopic, diffuse […]
What is the «conductor compression factor» of a cable? How does it affect performance?
Conductor Compression Factor in Electrical Cables The conductor compression factor refers to the ratio between the actual cross-sectional area of the metal in a stranded conductor and the area of the circle that circumscribes it. During the manufacturing process, stranded wires (typically copper or aluminum) are passed through a series of compacting dies. This mechanical […]
What are the key considerations for terminating and splicing armored power cables to ensure long-term reliability and electrical safety?
Armored Cable Termination and Splicing Reliability Terminating and splicing armored power cables (such as BS 5467 or IEC 60502-1 types) requires strict management of mechanical integrity, electrical continuity, and environmental sealing. The primary technical challenge lies in the armor earthing (grounding) and the management of electrical stress at the insulation screen cut-back. Long-term reliability is […]