University of South Wales Master of Sciences Thesis
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particular hour, N pv and N wg are the number of PV-panels and wind turbines respectively, and P pv(t) & P wg(t) are the powers generated from the PV-panel and the wind turbine at time t respectively. By multiplying the power from the renewable energy sources with time, the energy the renewable sources could generate at any time can be given by: 3.11 Where e res(t) is the energy generated from the RESs at a particular hour, and e pv(t) & e wg(t) are the energies generated from a PV-panel and a wind turbine at time t respectively. The energy from the renewable sources (Solar and/or wind) and/or Genset could be consumed by the demand directly or after it has been stored in the battery bank. Let’s see the most important cases that have to be considered when sizing the units. i. If the power from the PV/wind is greater than the load demand at a particular hour, the excess power must flow into the battery and the amount of energy stored in the battery bank when seen from the DC-bus is: 3.12 ii. When the load demand at a particular time is greater than the generated energy by the RESs and the battery bank has enough stored energy, the battery bank is used to help supplying the load. The stored energy which is left in the battery at each time t and when seen from the DC-bus is: 3.13 During this situation, it is assumed that the sum of the energy from the RESs and battery are at least capable of satisfying the load demand. iii. If the sum of the energy generated from PV/wind systems and energy available from the storage is not sufficient enough to supply the load demand, the Genset must turn ON to fulfill the demand. The energy required from the DG can be evaluated as at the DC-bus is: 3.13 |