| 摘要 |
FIELD: electrical engineering. SUBSTANCE: invention refers to system automatics and relay protection. Method is designed for location of faults in power transmission lines, in organs monitoring decay of magnetization current of arc in power transmission lines, for measurement elements of remote protection. Location of point of single-phase short-circuit in power transmission line with the use of its models is carried out by single-side measurement of voltages and currents of pre-emergency and emergency modes. In this case voltages of pre-emergency mode are fed to inputs of model of power transmission line with model of unobserved system connected to it and incorporating resistances of forward and zero sequences and voltage sources. Line model is balanced by currents by selection of voltage sources of unobserved system, then voltages of emergency mode are supplied to inputs of line model. Complex resistances of loads are connected at point of supposed fault to each phase. Model is balanced by currents by selection of specified resistances. Coordinate of point of probable fault in which resistance of load of faulty phase presents resistor and faulty phase is determined. Current in resistor is found. Source of specified current is connected instead of resistor. Emergency components of measured voltages and currents are determined. Sources are excluded from model of unobserved system. Emergency components of measured voltages and currents are fed to inputs of line model, line model is balanced by currents by way of selection of resistances of each phase of unobserved system. Imaginary parts of resistance of forward sequence of unobserved system are balanced with keeping their sum invariable. Active parts of resistances of forward and zero sequences are zeroed, source of current is disconnected from line model, sources of voltage are brought again into model of unobserved system. Voltages of pre-emergency mode are fed to inputs of line model and new coordinate of point of probable fault is determined in agreement with same sequence. Difference of new and previous coordinates is found, absolute meaning of difference is compared with setting and if it is less than setting point of fault is located by new coordinate but if it is bigger than setting then point of fault is continued to be located in same sequence. EFFECT: reduced time of location of single-phase fault, improved precision of method. 5 dwg |
