Microgrid Advantages And Disadvantages

1

ABSTRACT

This dissertation proposes a hybrid ac/dc micro grid to minimize the processes of multiple dc– ac–dc or ac–dc–ac conversions in an individual ac or dc grid and synchronization of DFIG with utility grid. The hybrid grid contains both dc and ac networks connected together by multibidirectional converters. DC sources as solar & battery and loads are connected to the dc network whereas ac sources as DFIG and loads are connected to the ac network. The proposed hybrid grid can operate in a grid-tied or isolated mode. Energy storage systems can be connected to dc or ac links. The coordination control algorithms are proposed for smooth power transfer between ac and dc links and for stable system operation under various generation and load

Local power generation and storage allow portions of the grid and critical facilities to operate independent of the larger grid when necessary and thus eliminate blackouts. The net microgrid could even provide ancillary services such as local voltage control, energy loss compensation; energy imbalance. This operation improves power quality to the customer. From the grid’s perception, the benefit of a microgrid is that it can be considered as a controlled entity within the power system that can be functioned as a single accumulated load.

The scale and type of benefits created from microgrids will also vary depending on customer and location-specific circumstances, including the thermal and electric demands of interconnected loads, the configuration of the local distribution system, the ability of existing macro-grid infrastructure to meet local or regional load growth, the local utility’s mix of resources and the retail cost of energy, among others.

1.4. Objective of the dissertation

The main objective of this dissertation is the development of a hybrid AC/DC microgrid and synchronization of DFIG output to utility grid which will reduce the process of multiple

consists of a photocurrent, a diode, a series resistor which describes an characteristic equation of a solar voltage characteristic of photovoltaic module for different Temperatures

Fig 3.5 represents current voltage characteristic in which the irradiance constant at 1000W/ and changing the temperature does not affect the short-circuit current but it reduces the open

A PV array consists of several photovoltaic cells in series and parallel connections. Series are responsible for increasing the voltage of the module whereas the parallel is responsible for increasing the current in the array. Typically a solar cell can be by a current source and an inverted diode connected in parallel to it. It has its own series and parallel resistance. Series resistance is due to hindrance in the path of flow of electrons from sistance is due to the leakage current. [31]

Fig 3.6 Equivalent circuit of a solar cell

Fig 3.6 represents equivalent circuit of solar cell. Generally the equivalent circuit of a PV model consists of a photocurrent, a diode, a Parallel resistor which expresses a leakage current and