A Study Of Power Transfer Of Fault Network And The Countermeasures Based On Wide Area Measurement System

In modern power system, the system structure and operation methods have become more complex which increase the risk of systemic accidents and large-scale power outages. And the accident at any point in the power system will affects the whole power system's normal operation in varying degrees. With the gradual application of Wide Area Measurement System (WAMS) which based on Phase Measurement Unit (PMU) in the power system, using the information measured by WAMS on real time on-line analysis of the power system operation status obtain a better effect.The power flow calculation and state estimation of the modern power system are based on the correct system switching value and network element parameters. In practical engineering, operating personnel may easily grasp inaccurate network parameters due to direct use of design parameters by lack of measured parameters, alternation of transmission lines, changes in operating environment, and units switching statuses'unclear. The grid parameter error would seriously reduce the analysis and calculation accuracy, thereby affecting the performance of a variety advanced applications based on the state estimation of the system. The paper gives an approach for solving the network structure parameters by using the fault network which based on PMU's measurement of the state on the line fault. This approach can quickly and accurately calculate power real-time parameters, so as to provide an accurate basis for system status analysis or the control strategy of emergency state.In the power network, the power transmission between nodes is not along a determined line between two points, but scattered these power in the various roads of the network according to a specific network structure. Power system power transfer usually occurs when the network topology changes took place. When the system in a particular tie-line was removed, the power on it will be transferred to the normal operation lines in the system and may lead to a normal circuit overload. This paper presents a method of through the on-line monitoring of the system power distribution before the line removed, combined with the system network topology and parameters to estimate the power distribution after resection of the line. and the method has been verified by a comparison with the simulation of real-time measurement of power distribution after the resection.Voltage stability problem is one of the most important issues that concerned by the electricity workers in recent years. With the development of power industry, the voltage stability problem has become particularly prominent and causing damage in some systems. This article studies the issues related to voltage stability, and present a voltage stability control strategy based on voltage stability index under emergency status. The method can figure out the power flow after the fault by using the Algorithm above during the failure period. And then the system can take corresponding control measures directly against the weak voltage stability points which could quickly lift the voltage stability security risk.