| The large-scale integration of intermittent energy has brought many problems to the operation and control of the power system.Since intermittent energy represented by wind power and photovoltaic are connected to power grid,the power fluctuation which is caused by environmental factors will bring voltage and frequency stability problems to the system.In order to ensure the safe and stable operation of power grid,the system needs to reserve sufficient peak or reserve capacity to cope with the fluctuation of power.However,problems such as insufficient capacity of frequency modulation and peak load regulation,unreasonable structure of the traditional grid power supply,and difficult power consumption are the main reasons that have restricted our large-scale development of intermittent energy.Therefore,they are of great practical significance to calculate the ability to accept intermittent energy of the power grid from the perspective of planning,in order to control the scale of grid-connected energy in macro point of view.Then study the dispatching methods of power system that involve large-scale intermittent energy.In this regard,this paper mainly conducted the following studies:Firstly,analyze the calculation principle of the photovoltaic acceptance capacity.Then,based on this analysis,this paper built a mathematical mode of the power grid,so as to achieve the purpose of reasonably expanding the scale of the photovoltaic power station and saving the fossil fuel.The model considered the system's peak-load regulation capability,took the optimal economical operation of the system as the goal,and took two conditions as constraints,which are the power balance of the power generation and the load as well as the technical conditions of each unit.Then we obtained a compromise decision on power system economy and photovoltaic acceptance capability.In this paper,it simulated a solar energy resource-rich province in northern China by classic Lagrangian relaxation method,to obtain the calculation results in level year 2020 and 2030.The results showed that the province still has some space for photovoltaic development,through reasonable planning and supporting power supply construction.Meanwhile,some measures can be put forward,such as pumped-storage power station,minimization of thermal power,and reduction of load peak valley.Secondly,in the foreseeable future,with the development of wind power and photovoltaics,it will bring difficulties to the active power dispatching of the power grid,which will not only increase the grid operation cost,but also increase the operation risk.Therefore,this paper developed a multi-time scale dispatching strategy,aiming at the power grid with intermittent energy connected.This strategy integrates the comprehensive advantages of day-ahead dispatching,within-day adjustments and automatic generation control system,to increase the use of intermittent energy while minimizing the impact of uncertainty and intermittent of power supply.This model aims at the lowest operation cost of the power system,based on 9 system requirements such as load balance and reserve capacity,to ensure safe and stable operation.Finally,by analyzing the role of inertia weights in the particle swarm optimization algorithm,we decided to use an improved particle swarm optimization algorithm to solve the multi-time scale dispatching model,to analyze its practicality.According to the actual situation,an example system with generator and load parameters was designed for calculation,and simulation results are presented in the form of scheduling effect diagrams.The results showed that the model has a significant effect on the optimization of the power system with intermittent energy.In addition,through the analysis of conventional generators' output data,research its characteristics and role in the dispatching process.At the same time,it is also concluded that the multi-time scale dispatching model can enhance intermittent energy acceptance. |
PDF Full Text Request