Title: Relay Setting Calculation of 220kV Power Transmission Line ABSTRACT The calculation plays a great part in the electric power system because the setting and use of protection have something with the security of system, the reliability of uses and have a close relationship with the economic settings, distribute, design of system. The article introduces the protection of EHV electric system and provides distance protection, zero-sequence protection, high frequency protection and automatic equipment. Firstly, the parameters of the power system components and the sequence impedances were calculated , then impedance diagram was drawn including positive sequence, negative sequence and zero-sequence. Secondly, according to the demands of system, the reasonable way of operation was chosen, then the fault location and how the fault occurs were chosen, the complex impedance by simplifying the networks was calculated. According to the kinds of fault and the knowledge of the faults in system, the full current was got at fault location. Thirdly, According to the construction of network, the current flowing the protected equipment was calculated. Based on the results above , the figures of all kinds of relay protection were calculated and checking whether the sensitive is proper, the reasonable scheme was analysed and the diagram of the setting of relay protection was drawn. Finally, the summary report of the setting calculation results was given, the calculations was evaluated and the available methods was proposed.
KEY WORDS: high frequency protection, distance protection, zero-sequence protection, automatic equipment
