large capacity and high parameters due to the rapid growth in consumption of modern life, agricultural and industrial consumption increased, formation of high voltage large capacity power grids, requires high-voltage electrical capacity and various parameters rapidly. Currently rated current from 1000A main power transmission and distribution equipment to 2500A to 4000A, short circuit current is increased from 16~20kA to 31.5~50kA, or even higher. 550kV circuit breakers single pole number of fracture has been reduced from 4 to 2, single break was developed. If a main force of China's power transmission and distribution voltage cannot be quickly promoted, then power on high voltage large capacity and high parameters of demand trend will not cool down (higher transmission voltage to unlock the subordinate distribution voltage ring network to reduce the power network short-circuit current).
electro-mechanical integration (intelligent) due to the development of computer and sensor technology and automation to improve, more urgent demand for high voltage apparatus intelligence function. Electric equipment and advanced light current technology can significantly expand high-voltage electrical functions, network automation, remote control, online testing provides better conditions. Large size, weight, features a single electromagnetic relay protection equipment, electrical instrumentation and control devices will be replaced by multifunction computer, sensors.