## 1 Introduction
The FACTS controllers of a STATCOM have a very fast response and flexible operation at dynamic circumstances with prescribed capacity ranges. Therefore, the DC capacitor voltages remain ripple-free for the system [34; 35; 36]. The submodule capacitor of three-phase multi modular converter sequences is being investigated to improve the system voltage imbalances and to limit the compensation current under dynamic grid conditions [37]. The proposed energy-based multilevel multicell inverter has been implemented to provide negligible total harmonic distortion for power quality issues in microgrid applications [38]. A half-bridge modular multilevel converter with the nearest level control technique is deliberated to minimize the cell losses in balanced power conditions [39]. The over current of a multi-level converter based HVDC (high voltage direct current) transmission system is controlled via fault ride through a control algorithm for smooth system operations [40]. A full bridge submodule of a modular multilevel converter built high voltage direct current transmission system is operated with capacitor balancing methods to avoid the sudden system interrupts [41]. The dynamic oscillations of power issues in the transmission system are stabilized by steady developments of the one cycle control flowchart of diode clamped multi converters based STATCOM [42]. Three phase voltage converters based STATCOM determines the real power and reactive power variations, and regulates the power deviations for stable system voltage levels [43]. Transmission power issues and voltage disparity are dissolved by a super capacitor energy system built STATCOM to maintain an efficient system [44]. This paper analyses the dynamic load variation conditions and their low total harmonic distortion with smooth stable operations for large level systems. A single DC-Link voltage of seven-level VSC-based STATCOM has been planned for reactive power regulation. It describes weighted transformer, minimum power electronic devices with coupled control methodology for stable voltage operations in a power system. The system indexed values of power, voltage, DC capacitor voltage, and firing angles are considered with satisfactory results, and the operations are discussed. The major contributions of the paper are detailed as follows:  
* A novel proposed seven level voltage source converter based STATCOM with single DC-link capacitor voltage is designed to enhance dynamic reactive power variations and stable voltage profile in a high-level voltage transmission system. * A novel seven level voltage source converter linked with binary weighted transformers is designed to meet the high rating voltages in a transmission system with low harmonic distortion. * In this proposed circuit, the switching angles are computed according to their levels of voltage source converters to maintain a constant voltage profile in the transmission system. * The proposed binary weighted transformer linked seven level voltage source converter is working with a decoupled algorithm to provide accurate results at various conditions of loads. * In this proposal circuit, the minimum number of power semiconductor switches and transformers are used to obtain better results than the conventional methods. The rest of the paper is structured as follows: Section 2 deals with the new approach of voltage source converter based STATCOM operation and novel firing angle equation design; Section 3 presents a decoupled control technique in order to regulate the reactive power changes and to maintain a stable system voltage profile; Section 4 shows the dynamic performance of STATCOM results; Section 5 details comparisons of this work; Section 6 concludes the proposed binary weighted transformer integrated seven level VSC based STATCOM performance.