基于STU的分布决策式配电网保护

In recent years, distribution system develops rapidly, a large amount of constantly improving penetration of distributed generations (DG) introduced into the power system changed the structure and the power flow of the distribution network and lead to the traditional distribution protection's malfunction, rejecting action, low sensitivity and so on. Protection for the distribution is facing a huge challenge. In this paper, combining traditional over-current protection and a new distributed wide-area protection, based on smart terminal unit (STU) distributed decision-making protection for distribution system is proposed. STUs access to real-time local datum of current magnitude and direction and process them into logical values. After logical calculation, the STUs meeting the condition access to adjacent STUs calculation results. Combining local and adjacent stations' logic value according to the criterion, STUs can judge the fault area and remove it accurately and fast controlling the local device. The protection method reduces the requirement for the communication channel greatly without synchronous sampling and solves the problem of the traditional distribution protection because of DGs introduced. At last, the results of simulation show the proposed protection method and reliability validity.