On the impact of the transitional mode in the mine site network on damaged phase time definition
Background. Protective shunting is becoming increasingly important in the modern concept of electrical safety of mine electrical networks. The most stringent requirements for reliability and speed imposed on the devices for selecting the damaged phase. In this regard, investigated the efficiency and speed of the previously proposed algorithm for determining the damaged phase under conditions when the neutral potential contains dynamic components determined by the transient process in the event of a leak. Materials and/or methods. For this purpose, the mathematical model of the mine network used to calculate the argument of the neutral potential taking into account the dynamic components and compared with its actual value and the boundaries of the reference phase intervals. The identification time determined by obtaining three consecutive calculated values of the neutral potential argument corresponding to the reference phase interval. The study performed for different values of leakage resistance. Results. Established that the algorithm provides reliable identification in the case of leakage resistance up to 10 kOhm in a time of not more than 11 ms. Also, the regularity of increasing the operating speed while reducing the leakage resistance revealed. Conclusion. In the conditions of increasing the requirements for electrical safety, as well as the increasing power and voltage classes of mine electrical equipment, the proposed algorithm can provide a reliable and rapid determination of the damaged phase for its subsequent shunting, thereby reducing the value of the leakage current up to zero.