Читать книгу Microgrid Technologies - Группа авторов - Страница 45

The use of two SSSCs in Generalized Unified Power Flow Controller (GUPFC) is aimed at controlling active as well as reactive power. In the proposed method, GUPFC installed for the same purpose by employing active sources like fuel cells to the common DC bus instead of BESS. The system shown in Figure 2.8 where the fuel cell is embedded with GUPFC in sub-system to ensure uninterrupted supply under all fault conditions.

The heavily loaded feeders get relaxation due to impedance control and voltage profile improvement after implementation of the proposed method. The dependability of generating stations on grid power for supplying auxiliaries will be considerably reduced with improved power quality at load side with or without grid connectivity when fed with active GUPFC based sub-system [17]. Figure 2.9 shows the general outline of the proposed system.

In reasonable working conditions as sub-system sources float, the main grid supplies power to sub-system loads based on demand. Whenever there is a grid disturbance and the main grid is unable to provide additional power to the sub-system, it has to separate from the main grid at a point of common coupling (PCC). The sub-system continues supplying power to the auxiliary system of generating stations. Figure 2.10 shows the condition when subsystem source i.e., DG embedded GUPFC fulfils the demand of auxiliaries.

The proposed method is an application for generating stations. In this research work, thermal generating stations considered as it has the highest installed capacity in India [3]. Due to the grid disturbance, a generating station, usually, experiences shortfall of power for running auxiliaries. This difficulty is overcome by using the energy from the sub-system. However, the stable operation of the sub-system is also an issue of concern when it has a renewable, nature dependent source. The use of fuel cells can provide an uninterrupted and stable power supply if installed with proper electronic converters.

Figure 2.8 Proposed system.

Figure 2.9 Proposed system with grid connection.

Figure 2.10 Proposed system without grid connection.