Research On Power Flow With FACTS And New Energy Resources

The development of society and the progress of science and technology increasinglystimulated people’s demand for electricity. The shortage of traditional energy and urgentrequirements for environmental protection, make the power industry to expand and improvethe existing centralized power supply of power grid, constantly develop new energy,strengthen the utilization of renewable energy, and then form a new mode of power supplycombined the large power grid with distributed generation technology. The scale of modernpower system is increasing and the topological structure and operation mode is more andmore complicated, make it hard to control the power comprehensively and flexibly, whichcause the rapid development of Flexible AC Transmission Systems. FACTS can flexiblycontrol the distribution of power flow and explore system’s potential transmission capacityand transmission potential in a greater extent, applying in power system more and morepopular. Using ac transmission technology or traditional dc transmission technology toconnect to the grid has many inherent defects for the inherent characteristics of distributedand intermittent of distributed energy, which can be well solved by using the flexible HVDCtechnology. In summary, modern power system has become a hybrid system containingFACTS, VSC-HVDC and distributed energy. In this case, the power flow distribution of thegrid is very different from the traditional power system, conventional Newton-Ralph methodhas been unable to adapt to the new power flow calculation. It is necessary to constantlyexplore a new flexible and efficient solution to calculate the power flow of this hybrid system.To solve above problems, this paper made the following research:1. Based on the original basic power flow calculation program and the existing powerflow calculation model and method of these FACTS devices, VSC-HVDC and distributedwind power, putting forward a general framework of calculating the AC-DC hybrid system.The power flow calculation method of the framework is an alternating iterative method basedon power injection, which is easily extended on the original program and suitable for a varietyof different control modes of FATCS, VSC-HVDC and wind power generators.2. Establishing a power flow calculation model of UPFC, the most powerful FACTS, andexpounding the algorithm principle and the derivation process of the method, which is using an alternating iterative method based on additional power injection. By simplifying the modelof UPFC to get the model of other FACTS devices, and then implementing a variety ofdifferent control modes of FATCS, and testing the validity of the model and the method.3. Establishing a power flow calculation model of VSC-HVDC, and then analyzingdifferent processing methods of the four common control modes of voltage source inverterand illustrating the method of calculating the dc network and whole power flow calculationprocess of VSC-HVDC.4. Establishing power flow calculation models of a variety of wind turbines, and thenexpounding the algorithm principle and the derivation process of their common control modes,and implementing and testing the power flow calculation of these modes.