Optimal Power-Frequency Control in Deregulated Thermal, Hydro and Hydrothermal Power Systems with AC-DC Links

Background: A comparative analysis of Automatic Generation Control (AGC) of two-area electric power systems interconnected by AC and AC-DC links under deregulated environment is conducted. Each area has Thermal-Thermal (TT), Thermal-Hydro (TH) and/or Hydro-Hydro (HH) multiple power sources. A maiden attempt is made to study the demeanour of HH power system under restructured mode. Methods: The state space models of the power systems have been developed to simulate all market transactions probable in a deregulated power environment and optimal proportional integral structured controller is applied to improve the dynamic performance. The concept of DISCO participation matrix is harnessed to simulate the transactions. Results: Eigenvalue analysis is carried out to assess the comparative stability analysis of the power systems with/without AC-DC links. Further, the dynamic responses of TT, TH and HH power systems are contrasted in the presence of AC link and AC-DC links. The inclusion of AC-DC links improves the dynamic performance of all the systems remarkably, however, the responses of HH system are sluggish/poor with large undershoots in comparison to TT and TH systems. Also, TH system exhibits degraded dynamic performance compared to TT system. Conclusion: Moreover, optimal controller is found competent to demonstrate the matching of generation with power demand under different market transactions.