| Transmission network planning is the basis for the safe and economical operation of power systems.At the present stage,the reform of power system and electricity pricing mechanism has put forward new requirements for transmission network planning.In the current supply-side structural reforms,reasonable transmission pricing is the basis and premise for achieving fair competition in the electricity market,and is also one of the important contents of the new round of electricity reform in our country.By the second half of 2016,all the provincial power grids in China have already implemented the reform of transmission and distribution prices.The new pricing method of transmission and distribution costs based on the permitted costs and reasonable returns has entered the preliminary application stage.In addition,with the maturing electricity market,the power system will face more uncertainties such as wind power,photovoltaic power and load fluctuation.Under this background,this paper studies the problem of multi-scenario probability planning in transmission network considering the impact of transmission price.Based on the traditional transmission network planning model and its solution method,this paper sets up the uncertain stochastic models of wind power generation,photovoltaic power generation and load fluctuation in order to meet the various uncertainties that will be encountered in transmission network planning.Study the random distribution of its active power.The power flow based on semi-invariant method is used as a tool to evaluate the steady-state operation of power system considering various uncertainties.The characteristics of transmission service cost and the factors of transmission price are analyzed.The transmission price is set as the fixed part approved by the government and the variation part affecting the transmission network planning.Taking the increment of transmission system reliability as the measurement index of the transmission price change.Through the reliability assessment of power transmission system,the two-state shutdown model is adopted for each transmission element,the non-sequential Monte Carlo method is used to simulate the system status,and the optimal load reduction model based on DC power flow is used to optimize the fault condition,Sexual indicators.Taking the reliability value corresponding to the increment of system reliability index before and after connecting the load and generator to the power grid as the component of transmission price fluctuation,the transmission price as the excitation signal correctly guides the power company and transmission service users to share the responsibility of the transmission system reliability.The transmission price considering the incremental value of reliability and its corresponding total transmission service revenue are included in the objective function of the transmission network planning model.The total cost of the whole life cycle of the transmission network expansion and operation is minimized.The total transmission revenue with the reliability considered maximizes,Multi-objective transmission network planning model with minimum load penalty on power transmission lines,multi-scenario probability selection technology and non-dominated sequencing genetic algorithm with elitist strategy are adopted to solve the planning model,and the comprehensive model based on the probability of occurrence of multiple scenarios Optimal solution,the non-dominated sorting of the Pareto fronts obtained optimal compromise solution to the problem,that is,under the influence of transmission prices under the grid optimal planning program. |
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