How to verify the sensitivity of relay protection
An operational current at relay terminals should be observed to ensure proper sensitivity. An assessment of sensitivity of the measuring elements of relay protection was performed. Based on simple examples of the generator-transformer unit protection from symmetrical short circuits, it was shown that the sensitivity factor is not a sufficiently objective measure of sensitivity of the. These systems are designed to identify abnormal conditions (which might include internal faults, short circuits (or) inappropriate operating currents) & isolate the faulty portion in order to avoid equipment damage, system instability (or) safety risks. The testing and verification of relay protection devices can be divided into four groups: Type tests are needed to prove that a protection relay meets the claimed specification and follows all relevant standards. So, in this case, to protect the whole line, the setting has to be able to detect fault current above 150 A.
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