Studies On The Fault Location And Protection Configuration For Independent Distribution Network

Ship power system consists of power supplies, power distribution devices, powergrids and loads, can be generally regarded as an independent power grid. In addition, theisolated island micro-grid is also an independent grid. During the actual operation, theseindependent power grids may run into variety faults or abnormal operating states, whichgreatly threatens the safety of people and devices. For large ships, the normal operation ofdistribution network has a very important significance for the safety of the ship. It isnecessarily that the relay protection act correctly and quickly. The main contents of thedissertation are as follows:(1) Expanding the traditional definition of the network description matrix, andpropose a new description of the network matrix and fault information matrix. Based onthe traditional network-description matrix, this paper also defines the terminal ends oflines without FTUs as nodes. And the corresponding fault information is defined as0andadded into fault information matrix. The adjacency relationship of the terminal feeder inthe distribution network can be described by the network description matrix, the faultinformation of both ends expressed by the fault information matrix. With the improvednetwork description matrix and fault information matrix, it is easy to locate the fault point.(2) Propose the fault location criterion based on the fault over-current value.According to the proposed computation formula of fault over-current, the paper willcalculate the over-current degree value of every sections when faults occurs. The sectionswhose value is greater than1are non-fault sections flew through by fault current, thesections whose value is1is the fault section, and the sections whose value is0arenon-fault sections not flew through by fault current. According to that, the criterion forfault location is presented.(3) Take the sixth generation deepwater semi-submersible drilling platform as amodel, the protection configuration for independent distribution network are discussed. Combined with the unique power characteristics of the offshore drilling platform, analyzethe types and characteristics of faults which may occur. According to different workingconditions of the drilling platform, establish the short-current calculation models,determine the protection configuration scheme based on the calculation results and settingprinciple. Operation results prove the effectiveness of the scheme.(4) Research the application of the fault location algorithm based on the degree offault over-current on drilling platform grid. Simplify the drilling platform grid to get nodes-branch topology map only consisting of switches and branch. The paper takes contactswitches as divide, and numbers nodes and sections for a sub-network to verify thecorrectness of the fault location algorithm based on the degree of fault over-current.At the end of the dissertation, a systematical summary is given. Further work to bestudied is pointed out.