Improving Dynamic Performance of Automatic Generation Control of Interconnected Power System by Combing Parallel EHV AC/ HV DC link

Abstract: This paper deals with load frequency control of 2 area interconnected Thermal power systems with EHVAC/HVDC links when subjected to small step load perturbations. For the present study, power system model consists of two areas thermal power plants having identical capacity. The system interconnection is considered namely (I) EHVAC transmission link only (II) EHVAC in parallel with HVDC transmission link. The HVDC link is considered to be operating in constant current control mode. To carry out the investigations, optimal AGC regulators are designed using proportional- plus-integral control strategy and implemented on the system under consideration in the wake of 1% step load perturbation in thermal area. The system responses will be simulated in Mat lab. Responses of deviation in frequencies, deviation in tie line power and integral of area control errors are plotted. By comparing the responses of the two model developed, one by using HVDC link and another without using HVDC link, the frequency deviation and settling time is lesser than without using HVDC link. Therefore by combining the transmission line by using HVDC link provides better dynamic performances in terms of overshoot and settling time.
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Keywords: Interconnected power systems; System dynamic performance; EHVAC//HVDC transmission link, MATLAB