current transformer LZZBJ9-10

LZZBj9-10 has its specific meaning:
L: "current" transformer
· Z: "pillar" type installation (directly fixed on the mounting plate, is the most common installation method in the high-voltage cabinet)
· Z: "cast" molding (with epoxy resin casting, with good insulation, mechanical and moisture resistance, suitable for indoor)
B: "with protection level" (indicating that this transformer has both measuring winding and protection winding, and is a "complex ratio" or "multi-winding" transformer)
· j: "increased capacity" or "enhanced"
9: Design serial number or serial number, representing a specific performance, structure or manufacturer's design version.
· 10: Rated insulation voltage of 10 kV (indicating that it is suitable for power systems with a voltage level of 10 kV)
Simple summary: This is a current transformer with increased capacity, which is used for indoor system with rated voltage of 10kV, pillar type installation, epoxy resin casting, with protective winding.
Main structure and working principle

1. Structural features:
Appearance: usually rectangular or approximately cuboid resin casting body, with metal mounting plate (with mounting holes) at the bottom, primary terminal (P1/P2) and secondary terminal box at the top.
· Material: The main body is made of flame-retardant, arc-resistant epoxy resin mixture vacuum casting, forming a solid whole. This structure can effectively prevent internal discharge and resist humid and dirty environment.
· Primary winding: Different from the low-voltage "through-type", there is a fixed primary winding inside the high-voltage transformer. The primary terminal usually adopts copper rod or copper bar structure, which is led out from the upper part of the casting body and is used for connecting 10kV primary circuit in series.
Secondary winding: There are multiple secondary windings wound on the internal iron core, which are used for measurement and protection respectively, independent of each other and without influence. These windings are completely sealed in an epoxy resin body. The secondary terminal is located in the terminal box on the side, and the outgoing lines of different windings (such as 1K1/1K2, 2K1/2K2, etc.) are clearly marked.
Main use

Due to its multi-winding characteristics, LZZBJ9-10 can realize multiple functions of one machine, saving switch cabinet space and cost:

1. High-precision electric energy metering (level 0.2): Connect the gateway electric energy meter or billing electric energy meter for high-precision metering of power plants, substation exports or important users.
2. General measurement and monitoring (0.5 level): connect ammeter, power meter, intelligent integrated measurement and control device, etc., for local display and system monitoring.
3. Relay protection (10P level): connect microcomputer protection device, overcurrent relay, etc. When a short-circuit fault occurs in the line, a signal is provided to cause the protection device to act quickly and cut off the fault circuit. Its high accuracy limit coefficient (such as 15) ensures that the signal can still be transmitted correctly in the event of a serious short circuit.