A new method for non-unit protection of power transmission lines based on fault resistance and fault angle reduction

A novel distributed unit transient protection algorithm using support vector machines

“…First, we define the following parameters [3]: T f is the occurrence time of the fault; f u is the voltage frequency; T k is the nearest zero-cross moment, at which the voltage changes from negative to positive, to T f ; Â u is the voltage phase angle at the relay site.…”

“…Hence, protection algorithms constructed by fault transient component can meet the performance requirement of ultra-high-speed action [2]. As a result, busbar protection based on fault transient component for EHV line protection has been widely discussed [3,4]. In [5], transient component generated by fault was applied to busbar protection for the first time wherein wavelet transform was utilized to extract the fault features.…”

“…In consideration of negative influences imposed by fault initial angle and transition resistance, a novel transient protection method that can eliminate the negative influences and greatly improve the protection reliability was proposed in [3], but the protection judgment still depends on traditional fault setting methods, namely, the same action values are set for all faults under different states. Notably, if the protection action values are set as different suitable parameters according to different fault states, the reliability can be greatly improved.…”

Research on a Faulty Line Selection Method Based on the Zero-Sequence Disturbance Power of Resonant Grounded Distribution Networks

“…Nowadays, most medium voltage distribution networks in China employ an ineffectively grounded (i.e., isolated or a anti-arc coil grounded) neutral to reduce overvoltage caused by SPG faults [1,2]. As a result, the very low fault current and unstable fault arcs make it difficult to detect faulty lines during SPG faults [3][4][5]. When a SPG fault occurs, the anti-arc coil over-compensates the total capacitive current in the network, and the residual fault current is not seriously harmful to the power supply equipment in a short time, but on the other hand it may leads to deadly consequences if the faulty line is not isolated from the distribution network in time, so it is very necessary to detect and isolate the faulty line automatically to ensure the reliability of the distribution automation and power supply.…”

Non‐communication protection scheme for power transmission system based on transient currents, HHT and SVM

“…In order to enhance the reliability of transient protection significantly, as indicated in [17], a new protection method with ultra-high speed was put forward for extra-high-voltage transmission lines, by which the adverse influence caused by fault initial angle (FIA) and transient resistance (TR) can be effectively reduced. Nevertheless, the traditionally fixed setting value was still adopted as the protection criterion in the method, i.e.…”