Study On Principle Of Adaptive Protection For Large Shipboard Power System

In recent years, with the full electric propulsion technology-based integrated shipboard power system and a large number of high-energy weapons, marine power system size and increasing the capacity, power system, the importance of the great ship subsystem increase is directly related to the Ship Survivability, and therefore the reliability of power supply ship a higher demand. To this end, a large ship from the low voltage grid upgrade to the 400V voltage 6kV or 10KV, the network structure from a single radial networks and network development for the ring-shaped network of more complex networks, more flexible operation mode and more change, these characteristics result in power failure a substantial increase in short circuit current, the traditional form to a simple fuse or current protection relay scheme can not meet the requirements of modern ships power grid, therefore, a large ship issues related to power system protection of great significance. Paper around the large ship's main power system backup program, adaptive protection, and network topology identification method in the pressure vessels by the high resistance grounding system, single phase power line detection, etc. The key technologies are studied and discussed .Ship power transmission distance is short, line impedance is very small, commonly used in terrestrial power system protection and current protection from the ship can not correctly locate the fault in the area, the paper failed selective differential protection based on the characteristics of the grid as a ship The main protection, distance protection obtained by simulation analysis and over-current protection should not be protected as a marine reserve network, according to ship small-scale power grid compared to the characteristics of the land, proposed to the centralized application of wide area differential protection of the marine reserve Adaptive Protection program grid, and gives the wide-area communication system fails in situ conservation programs.Large-scale marine power system operation mode species diversity, particularly in combat situations, combat damage and the cause of the failure resulting in frequent power system reconfiguration, network topology changing, and to achieve adaptive protection scheme must be on the network topology track identification, timely adjustment protective performance. This paper analyzes the network structure of large ships and power operating mode, the tree search method and the adjacency matrix together, presents a ladder can be used to ship multi-station network topology identification method, and the proposed marine power system protection programs compatible.Commonly used in marine power system grounding neutral small, single-phase ground short circuit fault feature is not obvious, resulting in protection systems are generally unable to identify the single-phase to ground fault, the need for a separate single-phase earth selecting programs. Land in the development of low voltage distribution network in a lot of line selection based on different principles approach, but in the actual field line selection device used in the accuracy is always unsatisfactory, mainly due to electrical failure is very small, sometimes difficult to detect by measuring device to. Thus thesis in pressure vessels by the high resistance grounding system, a novel alignment program, in the neutral point and then a small resistance, single-phase to ground fault current increases within a short time after the failure, the use of zero-sequence differential principle to achieve fault line.