Research On Planning And Operating Models And Decision-making Methods For Power System In Low-carbon Context

Electric power system plays an important role in transformation of primary energy to secondary energy and power transmission, distribution and use, which is one of the departments with the highest carbon emission level. Low-carbon economy and energy-saving policies bring power industry many challenges, and then the core businesses of power grid enterprises, such as power grid planning and investment, operation of power system and power supply, are faced with various challenges and risks. Under the context of low carbon development, power system should take its responsibilities, to guide the investment and planning of power system, to maintain the environmental and economic dispatching, to achieve the goal of energy-saving, and then to support low carbon development of national product. For this reason, we need to analysis the challenges and risks brought to power system by low carbon development, and propose effective solutions. Firstly, this paper analysed the influence of low carbon development strategy to the core businesses of power grid enterprise from the perspective of the power grid corporation; around the three core businesses, the generation and transmission coordinated planning and investment decision-making model, environmental and economic dispatching decision-making model and operating strategies for power grid corporation were researched respectively in the low-carbon context; finally, China’s low-carbon power system sustainable development and operating mechanism was built.Firstly, the influence of low carbon development strategy to the core businesses of power grid corporations from the perspective of the power grid corporation was analyzed, including power system planning, dispatching and operating. Overall, the impacts to planning outstand for the disorderly investment of renewable energy. As the weakening of unified power grid planning functions, generation and transmission planning isn’t coordinated well. The impacts to the dispatching are mainly for the large-scale connection of low-carbon generation resource with the intermittent and volatility characteristics, the goals of power system dispatching transform from the security and economy to security, economy and environmental, and then it puts forward more requirements to the decision and responsiveness capacities of dispatching department. The impacts to the operating of power system are mainly the requirement of pivotal role. Taking advantage of data imputation, the operators can built the low-carbon impact assessment decision-making mechanism supporting the three core businesses of power grid corporations with the low-carbon impact assessment of planning, dispatching and supply as the core, so as to continuously optimize business strategy for the entire power system and promote low-carbon sustainable development. Secondly, from the angle of the power grid enterprises construct a two-phase coordination planning investment model for power and grid under the background of low carbon. On first stage, the generation capacity investment portfolio optimization model considering renewable energy integration under low carbon, not only can provide comparison tables of generation capacity optimal planning for government departments, but also can identify installed share of other conventional power supply once the installed capacity of renewable energy changes, so it means the model can provide a decision-making basis about controlling installed scale in total amount on the supply side for the government departments. The model on second stage is about transmission grid optimal planning with constraints of carbon emissions. Through carbon emissions。 calculation and carbon price EGARCH prediction model, the model first gave a quantification process to carbon emission constraint and constructed an objective function to realize a minimum investment cost with comprehensive consideration of costs of transmission line investment, the grid loss, power generation and carbon emissions. Then the model utilized the intelligent simulated annealing algorithm to find solutions and through the integration of government departments, finally formed the optimal solution of low carbon power and grid coordinate planning.Thirdly, from the view of the power grid enterprises, constructed an environmental protection and economic dispatching decision-making model in power system under the background of the low carbon. Scheduling objective function containing the total fuel cost and pollutant emissions (CO2, sulfide, nitride) cost, making the balance and operating limits of transmission line loss’ real power as constraints. Furthermore, build a search radius difference evolution algorithm to find solutions of target function, and the global optimization solution can be found by changing search radius, which can avoid the problem that differential evolution algorithm is easy to trap into local optimum and achieve the global optimal. The environmental protection and economic dispatching decision-making model constructed above can provide technical supports for intelligent scheduling platform in the future.Fourthly, low-carbon production and operation mode in enterprises which takes low carbon evaluation as the core was studied from the point of power grid enterprise. Data of power generation, dispatching and consumption is gathered in power grid enterprise. According to the core impact of grid enterprise, this part distinguishes the relative indicators concerning power system planning and dispatching by separately taking generation, transmission and distribution and consumption as the subject, and designs the comprehensive low-carbon contribution evaluation indicator system. A comprehensive evaluation method based on grey triangular whitenization weight function was included to assess low carbon contribution of power system, and improvement measures for low-carbon production and operation in power supply enterprises were proposed. The low-carbon operation mechanism of grid enterprise, of which low-carbon contribution evaluation is the core, is dynamic, close-loop and continuous improvement, capable of providing decision-making basis for lowing carbon emission level of the whole power system.Fifthly, studies on decision-making methods of power system planning and operating, which innovate in theories to provide decision-making basis for relevant subjects, as well as the design of safeguard mechanism for coordinated planning of power supply and power grid are needed to build a power system of low carbon and high efficiency. Based on the fact that power system in China is still at the primary stage of low carbon development, a low carbon sustainable development and operation mechanism for power system is built, which includes the top level designs of power system’s coordinative planning mechanism and environmental protection and economic dispatching mechanism. It could provide policy supports for the orderly investment of renewable energy, the low carbon coordinated planning of power supply and power grid and the environmental protection and economic dispatching mechanism.