4 research outputs found
Power supply risk assessment method for relay protection system faults
The influence and the potential risk due to hidden faults of a relay protection
system on power supply in distribution systems are paid more and more attention to.
A probability analysis method is used to analyse fault characteristics and action mechanism
of dominant faults, hidden misoperation and non-operation of the relay protection
systems, and failure probability model of relay protection system is constructed and simplified.
The effects of dominant faults, hidden misoperation and non-operation of the
relay protection systems on the reduced power supply load power are analysed, and
a probabilistic model for reduced power supply load power is constructed by three parts
corresponding to dominant faults, hidden misoperation and non-operation. A probability
calculation method of power supply risk occurrence due to hidden faults of relay protecttion
system is proposed considering the fault probability of the relay protection systems,
the frequency of the hidden faults occurring in operation period, the reduced power supply
load power or load power outage, and the connection mode of the in-lines, out-lines
and transformers in a substation. The feasibility and applicability of the proposed method
for estimation of risk value probability of the relay protection systems is verified by two
studied examples