Load frequency control of interconnected power system in deregulated environment considering generation rate constraints

This paper deals with application of automatic generation control (AGC) to deregulated power system and makes a maiden attempt to provide a new practical AGC model to cater to the needs of a modern restructured hydrothermal power system. Several DISCO Participation Matrix (DPM) and Area Participation Factor (APF) have been tried out and dynamic responses for frequency, tie flow and generations are obtained to examine the performance of the system in deregulated environment considering integral controllers. Investigation has been carried out to study the effect of generation rate constraint and the importance of APF in deregulated environment. In this particular work hydro unit is considered with electric governor and thermal unit is considered with reheat turbine and mechanical governor. The primary purpose of the AGC is to balance the total system generation against system load and losses so that the desired frequency and power interchange with neighbouring systems are maintained. Any mismatch between generation and demand causes the system frequency to deviate from scheduled value. Thus high frequency deviation may lead to system collapse. This necessitates an accurate and fast acting controller to maintain constant nominal frequency. The limitations of the conventional controls viz., Integral, PI, and PID are slow and lack of efficiency in handling system nonlinearities.