DG Modelling Distribution Load Flow Analysis | Thesis Work Chandigarh
Today distribution systems are greatly changed in comparison with older conventional systems that used to provide the electricity power directly to consumer from transmission systems and consequently the conventional fossil fuel power plants based on gas and oil. Increase of roles of renewable energy resources in supplying energy and exclusively the power electricity of consumption levels is totally negligible and in addition to all advantages that it provides, there are certain concerns about changes in power flow directions in the distribution level of systems which can heavily impact the operation of protection relays and also provide inaccuracy in results of conventional load flow techniques that are used to analyze both distribution and even transmission line flows in power systems. Accordingly based on these facts, the load flow techniques and methods that are currently in use for providing accurate results for voltages and power flows are rapidly changing as well and this need should be met by considering some generators (as DG generators) in different levels of power generation in distribution level of system next to consumers. In contrast with previous models used to simulate power systems as systems that power is only flowing from generators levels toward consumers’ level in distribution section for costumers, today power flow is changed to a bi-directional flow and it can move even from distribution level toward main generators of systems in cases of low-load condition where power is generating by photovoltaic cells or wind blow for instance and it is not consumed directly by customers nearby.
Substation and Distribution system
Sub-transmission lines carry large amounts of power from the bulk power substations to the main distribution substations within the immediate area of use at intermediate voltages. The medium voltage network carries electrical power from the main distribution substations either directly to large industrial and commercial consumers or to distributor centres within residential areas at medium voltages. The primary feeders carry the electrical power from distributer centres to step down distribution transformers. The three-phase 380 V four-wire secondary cable carries the electrical power from the distribution transformer to building main switchboard.