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The increasing integration of regional power grids, rising penetration of multigeneration sources, and day-ahead power agreements have raised the operational challenges on deregulated modern electric energy systems. Among various challenges, frequency regulation becomes more prominent in the restructured power system (RPS) due to increased uncertainties and intricacies among other operational challenges. A minor deviation in system frequency affects the safety, quality, stability, and operation of the interconnected power system (IPS). An appropriate control mechanism and energy storage device are essential to regulate the system's dynamic responses during continuously varying loading conditions. This study proposed a novel Salp swarm algorithm (SSA) optimized fuzzy-based proportional-integral-derivative filter (FPIDF) controller with redox flow battery (RFB) to regulate the frequency of a realistic multi-area multi-source (thermal-hydro-gas) interconnected power system. All probable contract transaction scenarios are simulated that can be possible in a deregulated power industry. Various nonlinearities such as time delay (TD), governor dead band (GBD), and generation rate constraint (GRC) are incorporated to resemble the realistic operational conditions of the IPS. The effectiveness of the suggested controller has been validated by comparing the system performances with a recently published sine-cosine algorithm (SCA) based proportional-integral (PI) controller and SSA-PID controller. The investigation has been further extended by incorporating RFB in the proposed system. The study reveals that the suggested controller provided superior system control under various system uncertainties in all contact scenarios of the competitive electricity market. Additionally, the system performances have been significantly enhanced due to quick response and precise control offered by RFB.

The uncertain demeanour from wind generators and loads adversely affect the grid operational stability. Various control approaches have been explored to remedy the system uncertainties while maintaining generation and load demand balance. This study proposes a fuzzy‐based proportional–fractional integral–derivative with filter controller to sustain frequency stability in wind integrated power systems having different configurations. The controller parameters have been tuned using a recently developed coyote optimisation algorithm (COA). The proposed control approach is executed and validated on three distinct configurations of two‐area power systems. All test models are integrated with a doubly fed induction generator (DFIG) type wind turbine units (WTUs). Different case scenarios have been considered to analyse the efficacy of the proposed control strategy in the presence of WTU. Furthermore, the impact of inertial support delivered by the DFIG‐WTU and higher penetration of wind energy in the power system has been studied. The analysis reveals that the control scheme in coordination with WTU support reduces the stress on a wind turbine during the inertial control scheme and maintains the grid frequency stability under unexpected load disturbances. Stability and robustness analysis are also conducted to verify the validity of the introduced control approach.

Summary Growing electricity demand, environmental issues, and challenge to decrease dependence on fossil fuel resources have increased the inception of wind generation into the power system. However, higher penetration of wind‐based generating units into the existing grid can affect the working of the power system. Traditionally, a wind unit does not provide inertia, but collectively, wind units can have a notable impact on the dynamic performance of the power system. However, the battery energy storage systems have the potential to offer flexibility and ancillary supports to the power system. This article evaluates the impact of redox flow battery (RFB) in coordination with a doubly fed induction generator (DFIG)–based wind turbine unit (WTU) to enrich the dynamic performances of a multi‐source interconnected power system in a deregulated electricity market. The modified inertial control scheme is proposed for the DFIG unit that responds in the event of frequency deviation in the grid. The turbine sheds its kinetic energy and provides active power injection, thereby enhancing the frequency response of the system. The recently developed moth‐flame optimization (MFO) algorithm is employed for optimal tuning of the proportional‐integral (PI) controller and the speed regulator of a DFIG‐WTU. The simulation studies have been executed to analyze the impact of the RFB with WTU on the system frequency, tie‐line and different generating units power through a comparative study in terms of the settling time, and peak overshoot/undershoot in a deregulated electricity market. The analysis reveals that the WTU effectively contributes to sustaining the frequency and tie‐line power oscillations during abrupt load disturbances in the proposed power system. Moreover, the inclusion of RFB in coordination with the WTU helps to reduce the stress on a wind turbine during inertial control scheme. It can also reduce wind curtailments by absorbing excess power flowing through transmission lines, reduces wastage of green energy, and gives better dynamic response under different operating conditions of the deregulated electricity market.