Studies On DSP-based Feeder Terminal Unit

This dissertation will present the structure and development of Distribution Automation System and the function of Feeder Terminal Unit (FTU). The related techniques and computing equations for FTU are discussed in details, including AC sampling and harmonic analyses. Based on these studies, a scheme of FTU is given.By using the AC sampling techniques, it is possible for FTU to detect faults in time. The sampling period is tracking the power frequency by using the method of linear interpolation. It ensures the precision of all power net parameters. The FTU is based on the DSP-TMS320LF2407A. It calculates all parameters such as root-mean-square quantity, frequency, power factor etc. Moreover, to get a better knowledge of the power supply, Fast Fourier Transform Algorithm (FFT) is applied to harmonic analyses. According to IEC870-5-101 protocol, communications between the FTU and the control center are built up to realize the fault detection, fault isolation and automatic restoration of power supply in non-broken-down sections.The contributions of this dissertation are summarized as follows:1. An analog filter with an adjustable cut-off frequency gives a flexible design method. An idea of evolvable analog filter is presented based on the combination of programmable Analog Device and Genetic Algorithm.2. A RTOS is introduced as the software platform of the FTU. Considering the character of AC sampling, the RTOS based on μCOS is improved by using the sampling period as system clock tick. Therefore, strictly equal sampling period is guaranteed.