Fuzzy gain schedule based load frequency control of multi area thermal system under deregulated environment

Restructured power system creates independent utilities like generation, transmission, distribution companies and independent system operator. In the deregulated system, demand of each DISCO is met by many GENCOs. The system operator that takes care of the stability and reliability of the system offers many ancillary services. One of the ancillary services responsible for maintaining the system frequency and tie line power within limits is the load frequency control. During contract violation, the governor re-schedules the generator output to meet the un-scheduled demand. However, the frequency and tie line power deviates from the nominal value. These parameters are brought back within limits with the help of secondary proportional integral controller. The article applies the concept of fuzzy gain scheduling method to tune the secondary controller. The fast and effective response is checked and validated using performance indices.