The 33rd China International Exhibition on Electric Power Equipment and Technology
Shanghai International Energy Storage Technology Application Expo / Hydrogen Energy Expo
Power transmission and distribution primary equipment refers to all apparatus that is directly part of the electrical power circuit — carrying, switching, transforming, or protecting the flow of electrical energy at high voltage. This category encompasses power transformers, autotransformers, circuit breakers, disconnectors, busbars, current and voltage transformers (instrument transformers), surge arresters, capacitor banks, reactors, and cable systems. Primary equipment operates at the system voltage level (from 10 kV distribution up to 1,100 kV UHV) and must meet stringent dielectric, thermal, and mechanical performance standards. In China, primary equipment procurement is dominated by State Grid and Southern Grid, whose technical specifications set the de facto national standard. EP Shanghai is the premier platform for primary equipment manufacturers to demonstrate product compliance and connect with utility procurement teams.
5 Key Questions About Power T&D Primary Equipment
Primary equipment is directly part of the power circuit and operates at the system's high voltage level — it carries the actual load current and must withstand full system voltage and fault currents. Secondary equipment, by contrast, operates at low voltage (typically 110 V or 220 V) and performs monitoring, protection, control, and metering functions using signals derived from the primary circuit via instrument transformers. The distinction is fundamental to substation design, with primary equipment typically located in outdoor switchyards or GIS buildings and secondary equipment housed in control rooms.
Primary equipment in China must comply with GB (Guobiao) national standards issued by the Standardisation Administration of China (SAC), as well as State Grid Corporation (Q/GDW) and Southern Grid enterprise standards. International standards from IEC (International Electrotechnical Commission) are widely referenced and increasingly harmonised with Chinese GB standards. Key standards include GB 1094 (power transformers), GB 1984 (AC circuit breakers), and GB/T 5585 (busbars). Equipment supplied to State Grid or Southern Grid projects must pass type tests at CEPRI (China Electric Power Research Institute) or other accredited laboratories.
Digital primary equipment integrates sensors, communication modules, and intelligent electronic devices (IEDs) directly into traditional apparatus, enabling real-time condition monitoring, remote diagnostics, and automated protection. Smart transformers with built-in fibre optic temperature sensors, digital circuit breakers with integrated protection relays, and GIS with embedded partial discharge sensors are examples of this trend. The IEC 61850 communication standard enables seamless integration of digital primary equipment into substation automation systems, supporting the transition to fully digital substations.
Major failure modes include: insulation degradation (the leading cause of transformer and cable failures), contact erosion in circuit breakers and disconnectors, mechanical fatigue in operating mechanisms, corrosion in outdoor equipment, and partial discharge in GIS and cable accessories. Condition-based maintenance programmes use dissolved gas analysis (DGA) for transformers, partial discharge monitoring for GIS and cables, and thermal imaging for overhead line connections to detect incipient failures before they cause outages.
China's primary equipment market is driven by ongoing grid investment by State Grid and Southern Grid, the expansion of renewable energy connections requiring new substations and transmission lines, UHV network development, and the replacement of ageing equipment installed during the 1990s and 2000s grid build-out. The 14th Five-Year Plan targets significant grid investment, sustaining strong demand for transformers, switchgear, and cable systems. Export opportunities are growing as Chinese primary equipment manufacturers expand into Belt and Road Initiative markets across Asia, Africa, and Latin America.
Key Takeaways
Power T&D primary equipment forms the physical backbone of the electricity network, directly handling the flow of electrical energy at high voltage. China's world-scale grid investment programme creates sustained demand for transformers, circuit breakers, busbars, and associated apparatus. EP Shanghai brings together the full spectrum of primary equipment manufacturers and China's largest utility buyers under one roof.
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