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Sieyuan Electric supplied 245 kV dead-tank circuit breakers and floor-mounted local control panels for the S.E. Herradura Substation Project in Mexico.
245 kV Dead-Tank Circuit Breaker Solution Strengthening Mexico’s Grid Reliability
The S.E. Herradura Substation Project in Mexico is part of the CCC González Ortega grid reinforcement program. Sieyuan Electric supplied 245 kV dead-tank circuit breakers and floor-mounted local control panels for the project. The equipment was customized to meet the site's seismic, pollution, corrosion, wind, and altitude requirements, supporting reliable operation under demanding environmental conditions.
Project Overview
Sieyuan Electric supplied 245 kV dead-tank circuit breakers and floor-mounted local control panels for the S.E. Herradura Substation Project in Mexico.
Project Background
An AF5 (0.5g) seismic site with "Extra Alto" pollution, 160 km/h winds and a 0–2,500 m altitude range.
Key Challenges
Harsh environment, external insulation and corrosion protection, slow-open/slow-close operation and secondary equipment arrangement.
Sieyuan Solution
Reinforced dead-tank design, C5 corrosion protection, reinforced seismic structure, slow-open/slow-close device and floor-mounted LCPs.
Technical Highlights
Heavy-pollution insulation, environmental and mechanical adaptability, and an integrated secondary control solution.
Project Overview
Project Background
The project site is characterized by an AF5 seismic rating (0.5g), an "Extra Alto" pollution level, wind speeds of up to 160 km/h, and an altitude range of 0–2,500 m. These conditions placed additional requirements on equipment mechanical strength, external insulation performance, corrosion resistance, and environmental adaptability.
Key Challenges
Harsh environmental conditions — The equipment needed to withstand combined environmental stresses, including high seismic requirements, heavy pollution, salt-spray exposure, corrosion risks, high winds, and wide altitude variations.
External insulation and corrosion protection — The "Extra Alto" pollution level and industrial corrosion environment required enhanced external insulation performance and a higher level of corrosion protection compared with standard designs.
Slow-open/slow-close operation — The project required controlled-speed opening and closing functions to enable precise inspection of mechanism movement and contact travel during installation, commissioning, and maintenance.
Secondary equipment arrangement — The local control equipment required a high-protection integrated arrangement to provide a suitable environment for secondary components while facilitating site wiring and maintenance.
Sieyuan Solution
Reinforced dead-tank circuit breaker design — The proven dead-tank circuit breaker platform was customized with grey composite insulators and an enhanced external insulation design. The creepage distance was increased beyond the standard 25/31 mm/kV to reduce flashover risk in heavily polluted areas.
Enhanced corrosion protection — A C5 corrosion protection system was applied, with the hot-dip galvanized coating on steel structures increased from approximately 80 μm to 120 μm, together with specialized anti-rust treatment for protection against salt spray and industrial corrosion.
Reinforced seismic structure — The circuit breaker structure was reinforced to meet the AF5 (5 m/s²) seismic requirement. Safety devices, including explosion-proof membranes, were incorporated to maintain tank and support integrity under extreme conditions.
Slow-open/slow-close device — A slow-open/slow-close device was provided to enable controlled-speed opening and closing without operating power or during maintenance, supporting inspection of mechanism movement and contact travel during commissioning and O&M.
Floor-mounted local control panels — Floor-mounted local control panels (LCPs) with a high protection rating were supplied to integrate control, signaling, and monitoring circuits, while facilitating site wiring and maintenance.
Technical Highlights
Heavy-pollution insulation capability — The enhanced creepage distance design and grey composite insulators improve external insulation performance under the project's "Extra Alto" pollution conditions.
Environmental and mechanical adaptability — The C5 corrosion protection system and reinforced mechanical structure support reliable operation under combined corrosion, pollution, and seismic requirements, complying with LAPEM technical requirements for Mexican grid projects.
Integrated secondary control solution — The floor-mounted LCPs integrate secondary circuits and provide a practical arrangement for site wiring, commissioning, and maintenance activities.
