| Transmission lines are essential for continuous power delivery from generating plants to the end users. Applying series compensation in power system can reduces system losses, increase power transfer capability, improve transient stability, and enhance power and voltage control. More and more series compensations are used in modern power system.A transmission line is the part of the power system where faults are most likely to happen. The series compensated transmission lines are usually high voltage long distant line via complicate topography, so the chance rate of fault is higher. Determination of the fault point is vital for economic and safe operation of power systems and quality of power supply.The following work has been done.Synchronized sampling data of voltages and currents based on the GPS at both end of the line are used to calculate the location of the fault. Thinking about the character of the series compensation, a fault location algorithm of high accuracy and robustness is derived. In the algorithm, phase components are converted to modal components, and the fault position is calculated in modal domain. The algorithm is affected neither by fault resistance, fault type, fault position, the operation model of power system, nor by mutual inductances between different lines. Achieve the functions such as phasor diagram, frequency spectrum analysis. etc.An effective method is taken to judge whether the fault point lies at the left or right of the compacitor. According to the theory that the voltage waveform of real fault point calculated from each end would be overlapped, the real fault point can be determined. Comparing the sum of square voltage dispersion of fault point calculated from the both end the real solution can be computed precisely.Plenty of simulations are performed on the algorithms using the Power System Block set of MATLAB. And factors, which affect the accuracy of the algorithms, are analyzed. Simulation results show that the algorithms presented in this paper have high accuracy and robustness.Plenty of dynamic simulations are performed on the fault locator by using real-time digital simulation (RTDS) system. Simulation results show that highly accurate and robust results can be obtained using the locator. It's also found that it can be applied to a wide range of circumstances. |
