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15 2020-09: Power system relay protection device transformer protection classification
What are the transformer protection classifications of power system relay protection devices? 1. Longitudinal differential protection: including longitudinal differential, high impedance longitudinal differential, zero sequence longitudinal differential, generator transformer set longitudinal differential, and lead differential protection. 2. Gas protection. 3. Overcurrent protection: including negative sequence overcurrent, low voltage overcurrent, composite voltage overcurrent, and directional overcurrent protection, such as the generator transformer group shared, the low voltage overcurrent protection installed on the generator side is counted according to the generator protection. 4. Grounding protection: including gap grounding protection, zero sequence current voltage, zero sequence current protection. 5. Impedance protection. ...

15 2020-09: What do you still know about common sense about transformers?
1. Types and functional characteristics of transformers A transformer is an electrical component used to transform voltage, current or impedance. It is the main equipment for power transmission and distribution in a power system. The physical appearance is shown in 1-1. 1-1　The physical appearance of the transformer When transmitting power over long distances, the transformer can be used to increase the voltage sent by the power station to reduce the loss during the power transmission process and facilitate the transmission of power over long distances; where electricity is used, the transformer Reduce the high voltage for use by electrical equipment and users. There are many ways to classify transformers. According to the number of power phases, they can be divided into single-phase transformers and three-phase transformers...

15 2020-09: What is the differential protection of a transformer
The differential protection is the main protection of the transformer and is installed according to the principle of circulating current.　　 is mainly used to protect various phase-to-phase short-circuit faults that occur in the windings of dual-winding or three-winding transformers and their lead wires. It can also be used to protect single-phase inter-turn short-circuit faults of the transformer. Current transformers are installed on both sides of the winding transformer, and its secondary side is connected according to the circulating current method, that is, if the same polarity ends of the current transformers on both sides are facing the bus side, the same polarity terminals are connected, and the Connect a current relay in parallel between the two wires. The current flowing in the relay coil is the difference between the secondary currents of the current transformers on both sides, that is to say...

15 2020-09: The primary winding of the step-down transformer is
The relationship between the ideal transformer voltage (U) and the number of turns (n) is: U1/U2=n1/n2; the relationship between the ideal transformer current (I) and the number of turns (n) is: I1/I2=n2/n1. When U1U2, n1>n2, it is a step-down transformer.

13 2020-09: The secret of transformer operation
The secret of transformer operation

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