No abstract

At present, the MVDC distribution grid is developing rapidly and relay protection is the key technology to ensure stable operation. Therefore, this paper focuses on the fault line selection method. Firstly, the fault characteristics are analysed when a fault occurs in the line, and a novel single-pole fault line selection method is proposed based on 0-mode power. The polarity of current fault component measured at the terminal of each line is used to identify the internal and external faults. And the 0-mode power is used to select the faulty line. Finally, to verify the correctness of the proposed method, a radial MVDC distribution grid is built in PSCAD to output fault data in different fault conditions, and the fault line selection algorithm is implemented in MATLAB. The simulation results show that the proposed method is fast, effective, reliable and it has a certain degree of tolerance to transition resistance with a strong anti-data delay and anti-interference ability. Moreover, the fault line selection method proposed in this paper can still correctly select the fault line in the case of serious faults such as multiple line faults, sudden removal of lines, and sudden changes in photovoltaic output power.

The problem of sliding mode control for uncertain time-delay systems with input saturation and known external disturbance is considered. Combining T-S fuzzy model and sliding mode control method, we first establish the T-S model for the system, then an integral switching function is chosen, and a special sliding mode controller is designed such that the state trajectories can be driven onto the specified sliding surface in a finite period of time .Using linear matrix inequality and Lyapunov stability theory, we give a sufficient condition to guarantee the asymptotic stability of the sliding motion. An example is provided to illustrate the effectiveness of the proposed method.

No abstract