Addressed To DG Set With Constant Volume Network Architecture Based On Probability Trend Research Questions

During the operation, the grid will be disturbed by some external factors, such as a randomfluctuation of electricity load, random variation of power output, etc, in particular, most of thedistributed uncontrollable new energy’s access,the random of grid operation is becomingincreasingly apparent. In order to grasp the external disturbance affect on the system operatingconditions, We need to constantly monitor the system running, then a lot of flow calculation isnecessary. Traditional flow calculation is deterministic flow calculation that considers power output,load electricity, switch status are determined in advance,Traditional flow calculation isdeterministic flow calculation that considers power output、 load electricity//switch status aredetermined in advance, so the deterministic flow calculation can not reflect the randomness of gridoperation.Probability trend, with probability way of describing power output and load electricity,the calculation results are presented corresponding probability distribution, it can reflect therandom nature of grid operation.Probability trend has gained some successful application in many areas of power systemanalysis, such as net loss analysis、 assessment of reliability、 transient stability analysis,etc.Probabilistic load flow calculation can calculate the probability of overload lines、bus over voltageand other statistics, according to the probability distribution of the random disturbance load canobtain the amount of the unknown probability distribution function,it plays an important role in thediscovery and solve potential problems and weaknesses in the power system..Distributed Power (Distributed Generation, DG) combined with the traditional large powergrids is generally considered to achieve safe、reliable、energy saving and environmental protectionof power system operation mode, but also the future direction of electricity. Through pilot projects,to ascertain the effect of large-scale distributed generation of low-voltage network and mediumvoltage power distribution network, especially in positive guidance, to effectively deal with theattitude and grasp the characteristics, and gradually form an effective planning tool to ensure thatthe large-scale distribution containing power healthy and orderly development of the distributionnetwork to ensure all types of users within the distribution network, including distributedgeneration user safety,reliability,and analyzes the economic returns of various types of investments.When the DG is accessed to the distribution network, each branch of the direction of the trendwill change occurs,it will have some impact on the distribution network losses、node voltage、branch current、short-circuit current etc. These changes will affect the security and stability of thegrid, which leads to these changes not only related to the size of the load, but also with the DG of the installed capacity and the installation location of each node are linked. When a large number ofDG is connected to the grid will increase the power grid operation、control、difficulty scheduling.Therefore, how to choose a reasonable location and capacity of DG becomes very important.For the above problems, this paper contrasts and studied several common trends probabilitymethod, and finally choice the two point estimate of probabilistic method to calculate the trends.For a given distribution network structure, when the number DG、 position and size of the case arenot clear, from lower net loss、improve power quality、protection of power system security point ofview, distribution network planning of the economy including DG model is established. UsingMATLAB software programming, based on historical data of the actual grid load, geneticalgorithms, and ultimately get the optimal solution of DG’s location and volume.