Patent ID: 11885843

Abstract:
A method, system and apparatus for fault detection in line protection for a power transmission system. The method includes: obtaining a sampled value of voltage at a measurement point, at which a protection device for the line protection is installed, on an electrical line; obtaining a sampled value of current at the measurement point; calculating an instantaneous measurement point voltage value specified by operation criterion of a protection device from the sampled value of voltage at the measurement point and the sampled value of current at the measurement point by using measurement differential equation according to a time domain lumped parameter model for the electrical line; calculating an instantaneous comparison voltage value specified by operation criterion of a protection device from the sampled value of voltage at the measurement point and the sampled value of current at the measurement point by using comparison differential equation according to a time domain lumped parameter model for the electrical line; and performing the fault detection based on the comparison result of the instantaneous measurement point voltage value and the instantaneous comparison voltage value. The method transfers the distance relay to the format of voltage comparison, calculate the voltage using differential equation instead of vector, and compare the amplitude of calculated voltages. It designs a time-domain distance protection which has strong ability to resist DC components and harmonics including high frequency harmonic and low frequency harmonic.