Optimal Reactive Power Allocation in Distribution Grid with Emphasis on Voltage Stability Using Particle Swarm Optimization Algorithm

Abstract
The structured environment requires an appropriate solution to reactive power management. During the restructuring of the electricity industry, power systems were divided into three main parts: generation, transmission, and distribution companies, coordinated by an independent system operator. Active power is the most important commodity traded in the electricity market. The independent operator of the grid has the duty of providing the necessary conditions for the realization of energy contracts on the transmission grid at any time. The arrangements that are considered for the production and delivery of energy to the consumer are called ancillary services. Among the various ancillary services required in a competitive market, reactive power services to control the bus voltage are among the most important services provided by the system operator. Lack of reactive power in the grid is one of the factors that limit the fulfillment of energy contracts and can even endanger the security and voltage stability in the grid. In references, by assuming the results of the active power market is constant, the optimal load of reactive power is distributed. This model always entitles the generator to receive cost for the reactive power needed to stabilize its active energy.