Microprocessor Control of Substations

To use a microprocessor for the control of tap-changing transformer in automatic substations a system of hardware and software was developed. The hardware provides preprocessing and some isolation for the microprocessor while the software generates the control sequence and provides all necessary timing. The program occupies 2K of memory, of which about 1K is for auxiliary programs designed for versatility and with control of other components of substations in mind. The tap changing transformer was simulated and the control system was bench tested. The processor control time was 5%.