Derwent Classification System: Electric Power Engineering

Includes power generation, storage and distribution and electrical details for ground vehicles. Industrial use patents with significant electrical detail are also included. Patents relating to domestic electrical appliances need not contain electrical novelty to be included.

X11 Power Generation and High Power Machines (H02K, N) Conventional power generating prime movers. Dynamo-electric machines. MHD generators.
X12 Power Distribution/Components/Converters (H01B, H01T, H02G, H02J, H02M) High power AC, DC and HVDC distribution/control. Power and communication cables. Superconducting cables, coils and magnets. Installing power cables and lines. Power transformers, reactors. Spark gaps and circuits. Insulators. High power connectors. Power converters. Conductive, superconductive and insulating materials.
X13 Switchgear, Protection, Electric Drives (H02B, H02H, H02P) Electric machines and static power converters. Controllers. Switchboards, switchyards, switchgear. Power system protection. Circuit protectors, circuit breakers, fuses.
X14 Nuclear Power Generation (G21, H05H) Nuclear reactor processes, components and power plants. Control mechanisms. Plasma techniques. Particle accelerators.
X15 Non-Fossil Fuel Power Generating Systems (F03D, F24J) Geothermal, wind, wave and solar energy, types of power generation.
X16 Electrochemical Storage (H01M) Primary, secondary and fuel cells and batteries. Battery chargers. Non-electrochemical storage of electric energy.
X21 Electric Vehicles (B60L) Electric cars, trolley buses. Propulsion, braking. Power supply lines, current collectors. Traction batteries. Control equipment.
X22 Automotive Electrics (F02P) Vehicle accessories. Vehicle lighting. IC engine ignition. IC engine controllers. Batteries and charging. Starting motors, and generators. Engine and vehicle instrumentation. Non-engine related controllers eg. transmissions, brakes.
X23 Electric Railways and Signalling (B61) Propulsion, power and distribution, signalling, control.
X24 Electric Welding (B23K) Electric soldering. Arc, induction, electron beam, resistance, laser beam and HF welding. Electroerosion.
X25 Industrial Electric Equipment (H05B, F27) Electric furnaces and kilns. Resistance, induction, electric discharge and EM field heating. Electrostatic spraying and cleaning. Vibrating apparatus. Electrolytic processes. Electro-refining metals. Electrically powered tools. Industrial drying equipment. Ore separating magnets. Magnetic work holders. Lifting magnets. Sewing machines. Industrial components eg. pumps, fans.
X26 Lighting (F21, H01J, H01K) Discharge, incandescent and electric arc lamps. Operating and control equipment. Light fittings Portable lighting devices. Stage lighting equipment.
X27 Domestic Electric Appliances (A47, F24) Washing machines, dryers, irons. Vacuum cleaners. Electric cookers, microwave ovens. Kitchen equipment. Refrigerators. Water heaters. Space heating and air conditioning equipment. Personal and hygiene electrical appliances.