## 1 Introduction  
The role that flexible alternating current transmission system (FACTS) devices play in peak voltages and at high-power applications is significant to achieving reactive power variations and sustaining a system voltage profile. The transmission lines are key parts in electrical engineering to transmit electrical power and terminal voltage for all electrical appliance usages. Meanwhile, the control of electrical losses in the transmission system remains a major challenge, and FACTS controllers have fulfilled this requirement. A FACTS device (the static synchronous compensator (STATCOM)) is being used to control the losses in terms of reactive power variations and terminal voltage changes in the system. The insulated gate bipolar transistors (IGBTs) based series H-bridges combination of STATCOM provides the consumption of reactive power in either direction of the system and to improve the system stability [1, 2]. STATCOM has various models of multi-level converters for controlling reactive power. Voltage levels with direct current control techniques are able to harvest the system stability [3, 4]. The STATCOM FACTS device is being used to control losses in terms of reactive power variation and terminal voltage changes in the system [5; 6; 7]. Combining bridges and optimizing the number of switches results in minimum switching losses and reduces the cost in medium voltage transmission lines [8; 9; 10]. The reference voltage, reference current, constant DC-Link, pulse width modulation (PWM), fast Fourier transform (FFT), and micro processor based control (MPC) control schemes of STATCOM provide predictive power changes at dynamic load conditions [11; 12]. The stability of power in the transmission system has been settled by the hysteresis power regulations algorithm [13; 14]. The system nominal voltage is established via the additive control of linear and nonlinear loads [15; 16]. The voltage source converter (VSC) with PI controller limiters, decoupled link, hysteresis current, individual phase voltage, and current techniques is currently being implemented [17; 18; 19]. The bulk power rating of the high voltage direct current power transmission system's performance is estimated via modular level converters with mean value and equivalent versions of submodule circuits [20]. The irregular power losses, switching losses, and dynamic efficiency are improved with a dual-loop control scheme of half-bridge multi level inverters based on STATCOM [21]. The series-parallel device combinations of hybrid switched multilevel converters, which are designed and implemented for high voltage as well as high power applications with improved performance [22]. Energy storage STATCOM of modular multi level converter methods are executed for high-level grid applications with a control flowchart to evaluate the dynamic performance [23]. Inverter-based STATCOM is operated to set the real power and reactive power boundaries by limiting the system current and voltage for grid utility conditions [24]. Model predictive control is adopted as a superior control mechanism in transmission systems to overcome the power interrupts. The optimized switching vector-based STATCOM has been established to upgrade power quality in the system [25]. A multi modular converter with quadrature voltage compensation control method is used to compute the circulating current and to control huge power imbalances in the system [26]. This paper describes performance transmission system stability improvement in high power and high voltage commercial application with minimum power switches in STATCOM. The power variations are regulated and controlled by phase sequence algorithms [27; 28; 29]. Heavy loads (e.g., railway power grids and distribution networks) are being controlled with reactive current flows to obtain the constant voltage profile in demand of peak voltages as well as further voltages of power systems to comply with existing standards [30; 31]. The current control limitations are derived to maintain the system reference voltages [32; 33].