Fig .8 Simulation results with the transition resistance of 500Ω
at the fault point f1
As can be seen from Fig.8, when a fault with the transition resistance
500Ω occurs on the point f1, the fault components of the positive
current at 4 and 5 of the converter stations on both sides are both
positive, and the fault components of the negative current are both
negative. The current fault component waveforms collected from the
corresponding poles are positively correlated, with high similarity and
small waveform distance. Further, the corresponding current fault
waveform distance D1 is equal to 0.3882, which is smaller than the
setting value of Dset2. According to the protection criterion, the fault
is judged to be an internal fault.
In order to explore whether the protection works reliably and quickly
when other high resistance faults occur, simulations were carried out
for 250Ω and 500Ω transition resistors in different fault location
respectively. And the simulation results are shown in Table 5.
Table 5 Fault identification results of high transition
resistance of internal and external fault