Frequency regulation is in a first line of preference for an interconnected power system. Presence of nonlinearities in the generation systems further raises the complexity level of the problem. In this scenario, this article presents a robust Automatic Generation Control (AGC) mechanism to maintain the frequency and tie-line power of the power system to their nominal values. A Coefficient Diagram Method (CDM) based AGC mechanism including an AC/DC tie-line and Unified Power Flow Controller (UPFC) has been developed and the performance in handling the frequency regulation has been analyzed. The nonlinearities such as Governor Dead-Band (GDB) and Generation Rate Constraint (GRC) are included in the system to analyze the proposed AGC scheme in a more realistic approach. The AC/DC tie-line and UPFC which are included in the proposed AGC scheme provides an immense strength to handle the active power variation as-well-as frequency regulation. To develop a more effective AGC scheme, the parameters of an AC/DC tie-line and UPFC are optimized by successful implementation of the Fruit Fly Optimization Algorithm (FOA). The justification of the proposed AGC scheme has been carried out through a step by step verification such as justifying the CDM based controller, effectiveness of the proposed scheme and robustness of the system against parameters variation. The CDM based controller has been compared with the conventional controllers to elevate the effectiveness and the supremacy of the proposed AGC scheme has been examined by comparing with previously published work. The design and simulation of the work has been carried out by the MATLAB/Simulink® tool box.

The seawater desalination process is emerging as a substantial source of fresh water by removing salt and minerals from an infinite supply of seawater effectively. The first stage in a desalination plant is the use of chlorine gas to sterilize the microorganisms in the water. During excess chlorine leakage, an alert is activated, employees are relocated away from the site for a specific period, and dampers will be manually opened. This will cause unsafe working conditions and a waste of time. To overcome this problem, this paper proposes a coefficient diagram method based proportional integral derivative (CDM-PID) control strategy for the tune the control parameter with the distributed control system (DCS) interfaced conical tank. During operation, a 10% NaOH solution is injected into the top of the scrubber column using an ethylene-ter-polymer (ETA) designed distributor to ensure that the solution is evenly distributed across the packing surface. The three control strategies are compared to tune the control parameter with the DCS interfaced conical tank. Instead of the sodium hydroxide tank in the chlorine scrubber system, this work presents the pilot plant of DCS interfaced with two conical tank interacting systems with different liquid level heights. Here, the proposed CDM-PID controller is compared with the standard Ziegler-Nichols (ZN)-ultimate cycling method, and the internal model control (IMC) method. The results demonstrated that the proposed CDM-PID approach is superior to existing approaches in terms of low oscillation, settling period, and high robustness.