Real-time Slack Optimal Method For Volt/VAr Control Between Provincial And District Power Networks

Recently, automatic voltage control(AVC) system is important for power system running in the status of voltage security and economy. Since the further development of power systems interconnection, peak-valley difference of load is widening, the Volt/VAr close-coupled complexity is increasing, there still exist some severe problems in Volt/VAr control between provincial and district power networks. Based on the reactive power and voltage regulate requirements in provincial and district power networks, the shortage in the economy, real-time and adaptability of AVC system is pointed out in this paper. A real-time slack optimal method for Volt/VAr Control between Provincial and District Power Networks is proposed, it includes two parts as follows:decentralized slack optimal strategy and coordinated optimal strategy.In terms of decentralized slack optimal strategy. Aim at the fixed gateway reactive power control band cannot adapt to the changes in the operation mode. According to the analysis of principle of slack optimal distribution of reactive power in the grid, a differential setting method for gateway reactive power control band is proposed based on the “set the ΔP method” and the basis for setting “slack optimal network loss increase ΔP” is put forward. According to the method based on boundary conditioned parameter, gateway reactive optimization band based on the typical parameters is analyzed in 110 kV power grid. This strategy realizes the reasonable distribution of reactive power under different operation mode and ensure the economy of power system.In terms of coordinated slack optimal strategy. The mismatch of regulate measures will lead to the voltage mismatch of middle voltage side of transformer in the 220 kV power grid under extreme heavy load flow mode. Aim at this problem, a new model to evaluate the mismatch risk is proposed and the voltage mismatch criterion is considered in this model. An anti-mismatching strategy is proposed, and coordinate slack optimal strategy for volt/VAr Control between Provincial and District Power Networks is worked out to meet the both volt/VAr control requirements between provincial and district power networks under extreme heavy load flow mode and ensure the security of power system.Simulation results show : the proposed method can not only ensure security and economics of power system but also has the great advantage of real time and high reliability since it is not dependent on the accurate model for the entire network and power optimal flow, which is workable and has high practical value.