Although solenoid valves are "small components" in the power industry, they are widely used in thermal power, hydropower, nuclear power, new energy (wind/photovoltaic) and transmission and transformation systems, undertaking key functions such as fluid on-off, safety interlocking, automatic control and emergency protection. Its high reliability, fast response, and remote controllability meet the stringent requirements of the power system for safety, continuity, and automation.
Thermal power plant
(1) Boiler and turbine system
Hydrophobic control: Automatically open the drain valve to discharge condensed water during start-up, shutdown, or low load to prevent water hammer.
Soot blowing system: Control the intake/steam of steam or air soot blowers, and regularly remove ash from the heated surface.
Lubricating oil/jacking oil system: Quickly cut off or switch oil circuits during emergency shutdown to protect bearings.
Technical requirements: High temperature resistance (>300 ℃), high pressure (>10 MPa), often using metal sealing, stainless steel valve body, with Ex explosion-proof certification (oil system area).
(2) Chemical water treatment system
Control the addition of chemicals such as desalinated water, condensate polishing, ammonia/oxygen addition, etc;
Valve switching during reverse osmosis (RO) and mixed bed regeneration processes;
Integrate with pH and conductivity meters to achieve closed-loop control.
Material requirements: 316L stainless steel or PVDF, in accordance with GB/T 17219 (if boiler feedwater is involved).
Nuclear power plants (nuclear islands and conventional islands)
(1) Safe Injection and Spray System (SIS/ESS)
In a loss of coolant accident (LOCA), the solenoid valve quickly opens to inject boron containing water into the core;
The containment spray system is activated to reduce pressure and temperature.
(2) Equipment Cooling Water (CCW) and Critical Service Water (SEC)
Control the on/off of cooling water to ensure the heat dissipation of key equipment such as the main pump and diesel generator;
Automatically switch water sources in emergency situations.
Material: duplex stainless steel or titanium alloy, resistant to seawater corrosion (Binhai Nuclear Power Plant).
Hydropower station
(1) Governor oil pressure device
Control the pilot oil circuit of the main pressure distribution valve to achieve rapid adjustment of the guide vanes/blades;
When the accident pressure distribution valve is activated, the solenoid valve triggers an emergency shutdown.
Features: High frequency action, high response (<50 ms), mostly hydraulic pilot electromagnetic ball valves.
(2) Technical water supply system
Control the cooling water for the generator air cooler and thrust bearing;
Automatic backwash control of water filter.
Medium: River water containing sediment → requires wear-resistant and anti blocking design (such as Y-shaped filter pre installation).
New energy sector
(1) Thermal Power Generation (CSP)
Control the preheating, emptying, and emergency isolation of the molten salt circuit;
Water supply/discharge control of steam generation system (SGS).
Working condition: Molten salt temperature reaches 565 ℃ → High temperature bellows sealed solenoid valve is required, made of Inconel 625 material.
(2) Energy storage and hydrogen power plants
Control the hydrogen/nitrogen purging pipeline;
Cooling fluid on/off in battery thermal management system (liquid cooled energy storage cabinet);
Pure water supply control for PEM electrolysis cells.
Requirements: Zero leakage (ISO 15848 Class VI), explosion-proof (hydrogen environment Ex d IIC T6).
Power transmission and auxiliary systems
Transformer oil temperature control: start/stop cooling fan or oil pump (through control relay circuit);
SF ₆ Gas Insulated Switchgear (GIS): monitors the pressure in the gas chamber and triggers an alarm or locks in case of abnormalities;
Fire fighting system: water spray/gas fire extinguishing starting valve in main control building and cable interlayer;
Air compression station: Control the outlet of the instrument air storage tank to ensure the stability of the DCS air source.