The penetration of renewable energy sources and energy storage (ES) units into the distribution system has increased, and it is important to examine their effect on the systems' operation scheme and security. Voltage stability index is defined as a security objective function, and its improvement by energy management in the distribution network is a major challenge in this study. The dynamic distribution feeder reconfiguration (DDFR) is introduced as an efficient approach for energy management in the distribution network, considering energy loss, voltage stability index, and operational cost as objective functions in the presence of distributed generators, solar PV panels, ES units, and capacitors. The demand response program, including interruptible/curtailable service, is proposed to enable energy consumers to rethink their energy consumption patterns based on incentive and punitive policies. A modified particle swarm optimization algorithm is presented to solve the considered optimization problem. The suggested approach is tested on the 95-node test system and its superiorities are shown through comparison with other evolutionary algorithms. Based on the obtained results, after presenting a new model based on DDFR for energy management in the distribution system, energy loss and voltage stability are reduced by 25% and 2.8%, respectively. After applying the demand response program in the proposed model, energy loss and operational cost are reduced by 26% and 5.9%, respectively.