In this, a new Higher-Order Reduction (HOR) scheme is proposed for better understanding and explanation of a large-scale dynamical (LSD) system. This proposed scheme is based on a balanced realization method (BRM) in which the steady-state gain issue of the BRM is circumvented. This method guarantees that the system is stable and preserved static behaviour. The reduced-order model (ROM) is calculated to maintain entire parameters with fair accuracy by model order reduction (MOR). Further, in terms of transient and frequency responses, the performance of the proposed scheme is analysed. In this paper, we have used two approaches that are balanced realization method (BRM) and stability equation method (SEM) for HOR. According to that procedure, the denominator coefficients (DC) of the reduced model is obtained by BRM and the numerator coefficients (NC) are computed by SEM. This technique gives the least performance error indices compared to some another existing approaches through a literature review. Additionally, the control action is obtained by using the genetic algorithm (GA) based PID (proportional integral derivative) controller has been proposed. In this tuning optimized PID parameters done using of objective functions, the concept of error minimisation (performance index). As the proposed approach is used both in the simplification of systems and in the design of controller, therefore it may be applied in various applications of LSD system analysis and design. The proposed scheme is proved by a numerical example. العلوم فرع فيصل، امللك لجامعة العلمية املجلة والطبيعية األساسية ، الطباعة) (بانتظار العدد الطباعة)، (بانتظار املجلد