| The basic task of network planning is to develop the power system as economically as possible with satisfying a certain level of security and reliability. As power system operation mode becomes more complex, along with the stricter requirement on system security, the approach of taking economic index as planning objectives is no longer applicable. How to measure the system security and economy on a unified scale to obtain the optimal network planning becomes an urgent issue for in-depth study.This paper firstly foucus on the security issue of network planning and study s on the security risk assessment in view of system operating mode based on the probability theory. Secondly, considering the "N-1" security constraints and taking investment costs, network loss costs, and congestion cost as the objective function, the economy model of network planning is established. In addition, the economic cost model of security is put forwared by quantitatively characterizing the security risk index as power outage cost. By adding the power outage cost into the objective functions of the economy model, the optimal planning model with security and economic coordination is estabilished. Furthermore, exponential decreasing strategy of inertia weight as well as crossover and mutation, disturbance and other operations are taken to deal with the Particle Swarm Algorithm (PSO) premature characteristic. Meanwhile, an modified particle swarm optimization (MPSO) is approached and applied to solve the coordination model. Finally, Taking the IEEE-RTS24 system as an example, the optimal planning schemes of economy model and security and economy coordination model are comparely analyzed, and its feasibility and practicability is validated. The results show that the coordination model meets the system security requirement while improving the benefits of network planning investment and operation, which can provide quantitative decision-making basis for future power network expansion and renovation. |
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