Low-power electronic current mutual inductor

Abstract

A low-power electronic current transformer is a passive device, including: a primary winding, a secondary winding, a magnetic core, a secondary shunt resistor, a shielded shell, a double-shielded twisted pair and a base, and the primary winding runs through the magnetic core In the center, the secondary copper wire is evenly wound on the magnetic core, the shielding shell and the base form a whole, and a secondary shunt resistor is connected to the end of the secondary copper wire, and the secondary shunt resistor is evenly wound on the ring magnetic core. The winding and the secondary copper wire constitute the secondary winding, the secondary winding is placed in a shielded casing, and the secondary low-power voltage signal is output by a double-shielded twisted pair. The secondary output of the present invention is a low-power voltage signal that is linearly proportional to the primary current; one transformer winding can meet various requirements for measurement and protection at the same time; the measurement range is large and the precision is high; there is no secondary loop problem, and it can be opened. It can also be short-circuited; it is small in size, light in weight, low in raw material cost and strong in electromagnetic compatibility.

Description

technical field [0001] The invention relates to a transformer used in the technical field of electric system current measurement and relay protection, in particular to a low-power electronic current transformer. Background technique [0002] With the widespread application of relay protection and measurement systems based on microcomputer technology, the power requirements for input signals are greatly reduced. In practical applications, since the energy level provided by these signals is far beyond the range that microelectronic components can withstand, they must be further converted into low-power analog voltage signals through current / voltage transmitters before they can be input to relays Digital signal sampling is carried out in the analog / digital conversion module of the measuring system. In the current power transmission and transformation system, the acquisition of the primary high-voltage current signal is mainly realized through the traditional electromagnetic cu...

AI Technical Summary

Problems solved by technology

The main problem of this technology is that the power supply of the electronic circuit on the primary high-voltage side and the service life of the long-term operation are short. At present, the main power supply methods include laser source power supply and busbar coil power supply (that is, using a small current transformer coil from the primary The high voltage side obtains power supply)

The main problem of laser source power supply is that the emission power of the laser source is low, the power provided is limited, and the price is high and the service life is short, which makes the manufacturing cost of the hybrid photoelectric current transformer very high, and it is difficult to maintain on site after operation.

However, when the coil of the bus-type current transformer is used for power supply, there is a problem of "dead zone" of the power supply that the coil is easily saturated when passing a small current once, and the coil is easily saturated when passing a large current, which affects the stable operation of the electronic circuit.

Therefore, although some products of this hybrid photoelectric current transformer are connected to the grid, it is still difficult to achieve large-scale production and application.

Images