Research On Models For Micro Integrated Energy System Day-ahead Scheduling

As the current international and domestic economic situation and energy situation is undergoing profound changes, the energy revolution has begun. On the ground of development of clean energy, climate change, energy security, economic growth needs, countries have proposed the concept of smart grid and it has become an important part of the national strategy. Integrated energy system, developed on the basis of smart grid, involving a variety of forms of energy, using information technology and internet technology, upgrade the existing energy system to better serve customers, improve the utilization efficiency of energy systems, promote energy market liberalization, and create new economic growth point. Micro integrated energy system not only has a limited coverage, small number of load and relatively simple load model, but also has a good engineering foundation based on communication platform and information platform. This paper focuses on models for micro integrated energy system day-ahead scheduling. The main work and achievements are as follows.1) An interaction load model was established, including shiftable load, curtailable load and transferable load, which was applied in microgrid day-ahead economic scheduling under the interaction environment. First, the proposed model for shiftable load was described by integer variable and power distribution vector, which immensely reduces the model scale. Second, the involved model for curtailable load considers interaction frequency and duration. Third, the one for transferable load regards transferable timespan. Even more important, the model remains linear; as a result, the solution is independent of initial points when solved by an optimization solver. The contents of customer interaction contract were discussed. A case was performed to verify the proposed model.2) Combined heat and powe(CHP) plant is the most common element in micro integrated energy systems. Based on the research on output characteristics of CHP, a convex programming model for CHP work area was established, which covers the whole operating region. CHP fuel cost is a nonlinear function of thermal output and power output and the hermoelectric coupling model causes convergence difficulties. Two auxiliary power variables were introduced to decouple CHP fuel cost function. A mixed-integer linear programming model was established for micro integrated energy system day-ahead scheduling. A case was performed to demonstrate the effectiveness and suitability of the proposed model.3) An integrated energy system architecture was proposed including combined cooling,heating and power system and demand-side resource; models for electric heat pump and absorption chiller were formed.To solve the problem of frequent switching between heating and cooling mode of electric heat pump, an switching cost model was created A mixed-integer linear programming model was established for micro integrated energy system day-ahead scheduling and numerical example showed the effectiveness of the proposed model.