The difference between the action principle of the main variable light and heavy gas protection
Corresponding protection devices shall be installed for the short-circuit faults of the transformer lead wires, bushings and internals, and shall meet the following requirements: 1) The single-running transformer of 10MVA and above and the parallel running transformer of 6.3MVA and above should be equipped with longitudinal differential protection. Important transformers with 6.3MVA and below operating independently can also be equipped with longitudinal differential protection.2) Transformers below 10MVA can be equipped with current quick-break protection and overcurrent protection. For transformers of 2MVA and above, when the current quick-break sensitivity coefficient does not meet the requirements, longitudinal differential protection should be installed. 3) 0.4MVA and above, the primary voltage is 10kV and below, and the coil is a transformer with a delta-star connection, and a two-phase three-relay type overcurrent protection can be used.4) The various protection devices specified in this article shall operate to disconnect the circuit breakers on each side of the transformer.