Методика выбора параметров противоаварийных команд на отключение потребителей в сетях 0,4 кВ

Abstract

Conventionally, when accidents entailing active power imbalance occur in a power system, the underfrequency load shedding devices disconnect the necessary and sufficient amount of loads at the 10 kV voltage level. These load shedding operations are carried out without the possibility of taking into account the importance of certain consumers at the 0.4 kV voltage level. What is more, in view of using loads highly sensitive to power supply continuity, recent years have seen more stringent requirements being imposed on the reliability of their power supply. On the other hand, the availability of new computerized facilities opens the possibility of improving the reliability of supplying power to them even in the emergency load limitation mode. Specifically, this can be achieved by integrating the existing relay protection and automatic control systems with the automated electricity consumption monitoring and control system in such a way that consumers at the 0.4 kV level are selectively disconnected by commands of the underfrequency shedding control devices installed at the 10 kV voltage level. The article considers issues concerned with elaborating a procedure for selecting the values of the information parameter specifying the duration of command signals for disconnecting 0.4 kV loads produced by the automatic underfrequency load shedding devices at the 10 kV voltage level. It is proposed to perform load shedding operations by using a new method developed at the Moscow Power Engineering Institute National Research University. According to the proposed method, loads operating at the 0.4 kV voltage level are selectively disconnected through artificially creating a voltage sag (interruption) and using it as the underfrequency shedding command signal for disconnecting less critical loads. The article presents the principle of tuning-out from possible events and phenomena in the power supply network internal and external parts taking into account the existing setpoints of the relay protection and automatic control devices, and the influence of motor loads in generating and transmitting the command signal for short-term interruption of voltage via the 10 and 0.4 kV power network. A procedure for selecting the timing tuning parameters of the emergency control command generating and receiving devices.