Transformer is an essential electrical equipment in the process of power distribution and power transmission. Due to the importance and continuity of transformer work, the corresponding transformer will have a lot of protection. Today we will focus on the following: The definite time limit of the transformer over-current protection See how the time-limited over-current protection works. A, a definite time transformer overcurrent protection overcurrent protection scope of the transformer, but also a highly protective. Transformer definite time limit over-current protection is installed on the power supply side of the transformer to reflect the over-current of the transformer caused by faults outside the protection scope of the transformer (outside the zone), and serves as backup protection for current quick-break protection. The operating current is set to escape the maximum load current of the transformer. In order to make selective relay protection actions for the upper and lower electrical equipment, the overcurrent protection adopts the step-by-step principle in setting the operating time, that is, the protection time of the upper protection located on the power supply side is longer than the protection time of the lower protection. Principle wiring diagram Second, the overcurrent protection's operation time limit is fixed once it is set, which constitutes the definite time limit over-current protection. Figure 7-3 is the wiring diagram of the definite time transformer over-current protection principle. When the current of the transformer being protected exceeds the setting current of the relay KA, both IKA and 2KA relays, whether one action or two actions, the closing contact of the relay 1KA or 2KA is closed, and the coil power of the time relay KT is turned on; The relay KT is started. After a preset time, the time-delayed closing and closing contacts are closed and the relay power of the intermediate relay KM is switched on; the intermediate relay KM is activated, the KM's closing contact is closed, and the signal relay KS current flows. Coil, circuit breaker QF The auxiliary contact QF1 turns on the power of the trip coil YT, the circuit breaker QF trips, and the faulty line is powered off. At the same time when YT is turned on, the signal relay KS is started, and the manual resetting of the movable contact is closed to send a signal. Third, the analysis of the definite time transformer over-current protection development diagram. Figure 7-4 is a development diagram of the transformer definite time limit over-current protection. In the figure, +KM, KM is the DC operating power supply, and QF1 is the moving auxiliary contact of the circuit breaker QF. When the QF trips, QF1 is disconnected to ensure the tripping coil. De-energize the YT to prevent burn out of the coil due to prolonged energization. With regard to the time-limited current limit of the transformer, it is said here that there are better suggestions for friends who can leave messages below, learn to share electrical and electrical knowledge together, and make progress every time! Plastic Bottle Packaging,250Ml Plastic Bottles,Empty Plastic Containers,Clear Plastic Bottles With Lids Hangzhou Sunshine Packaging Technology Co,.Ltd , https://www.zizemojia.com