1. Multi-tap current transformer. The primary winding remains unchanged, and when winding the secondary winding, several taps are added to obtain a plurality of different transformation ratios. For example, two taps are added to the secondary winding, K1 and K4 are 800/1A, K1 and K3 are 600/1A, and K1 and K2 are 400/1A, that is, the conversion ratio is 400-600-800/1A according to the load current conversion ratio, and the wiring of the secondary terminal block is changed to change the transformation ratio, without replacing the current transformer. Because the secondary winding capacity is usually related to various factors such as the number of turns of the secondary coil, the cross-section of the core and the accuracy level, the secondary winding capacity of the transformer with the middle tap cannot be made the same, such as 800/1A is 30VA, then 400/1A may be 15VA.
When connecting the cable, you only need to connect the corresponding ratio terminal, and the unused terminal cannot be shorted when it is empty. The current transformer with intermediate tap for 10 kV switchgear can lead each terminal to the secondary terminal row of the switchgear for easy access and use.
2. Different ratio current transformers. The current transformer has the same core and primary winding, while the secondary winding is divided into two independent windings with different turns to meet the needs of different transformation ratios and different accuracy levels under the same load current, such as 400/1A, 0.2S for 1K1 and 1K2, 800/1A and 5P30 for 2K1 and 2K2, that is, different transformation ratios for protection and metering.
3. The primary winding is adjustable, and the secondary multi-winding current transformer is adjustable. The primary winding of the current transformer is divided into two sections, which pass through the core of the transformer, and the secondary winding is divided into two independent windings with taps and different accuracy levels. The primary winding is connected by a connecting lug on the outside of the transformer (near the primary terminal board), and in the state of power failure, the primary winding is formed in series or parallel connection by changing the connecting lug, so as to obtain different ratios of 2 times the relationship (with 2×? /1A). The secondary winding with tap itself is divided into two windings with different transformation ratios and different accuracy levels, and with the change of the position of the primary winding connecting piece, its transformation ratio also changes, forming a multi-range transformation ratio. For example, when the primary winding of the current transformer is connected in series, 1K1, 1K2, 1K2, 1K3, 2K1, 2K2, 2K2, 2K3 are 400/1A, and 1K1, 1K3, 2K1, 2K3 are 600/1A; When the primary winding of the current transformer is connected in parallel, 1K1, 1K2, 1K2, 1K3, 2K1, 2K2, 2K2, 2K3 are 800/1A, 1K1, 1K3, 2K1, 2K3 are 1200/1A, that is, the transformation ratio is 2×600/1A, with 400/1A, 800/1A intermediate tap.
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