Current transformers technical parameters

First, the current transformer models:
First letter: L-current transformer
The second letter: A-through the wall; Z-pillar; M-bus type; D-type single turn throughout; V-structure inverted; J-zero sequence
Ground detection; W-anti-contamination; R-winding bare formula
The third letter: Z-epoxy mastic; C-ceramic insulation; Q-gas-insulated medium; W-specific and computer protection
The fourth letter: B-band protection level; C-differential protection; D-D level; Q-enhanced; J-reinforced ZG
Fifth figures: voltage level product serial number
Second, the main technical requirements
2.1 Rated capacity: Rated secondary current through the secondary rated load apparent power consumed. Rated capacity can be expressed by the apparent power VA, you can also use secondary rated load impedance Ω represents.
2.2 A rated current: the current transformer primary winding allows electricity load current. Current transformers for power transformers system once rated current 5 ~ 25000A, used test equipment, precision current transformer is 0.1 ~ 50000A. Current transformers in

A rated current in the long run, the load current exceeds the rated current value is called overload, overload current transformer long run, it will burn out the winding or reduced service life.
2.3 Secondary rated current: Allow a current transformer secondary winding induced current.
2.4 Rated current ratio (ratio): a rated current and the secondary rated current ratio.
2.5 Rated voltage: primary winding long on the ground to withstand the maximum voltage (in kV rms), shall not be less than the rated phase voltage connected to the line. Current transformer rated voltage divided 0.5,3,6,10,35,110,220,330,500 kV, several

Kind of voltage levels.
2.6 10% Multiples: secondary load at a specified and arbitrary power factor, the current transformer when the current error of -10%, a current rating of its multiples. 10% protection factor is related to technical indicators.
2.7 Accuracy Class: Indicates transformer itself, error (difference and angular than poor) grade. Current transformer accuracy class is divided into multiple levels of 0.001 to 1, compared with the original accuracy improved greatly. Used in power plants, substations, power distribution unit on the control panel

Electrical instrumentation generally use 0.5 or 0.2; used equipment, line protection is generally not less than 1; for energy measurement, depending on the load capacity or power consumption measured according to how many procedures required to choose.
2.8 ratio error: error includes transformer ratio error and phase error in two parts. Error ratio worse than short, generally expressed by the symbol f, which is equal to the actual secondary current and converted to the secondary side of the primary current difference, and converted to the secondary side of a current ratio to one hundred

Fraction.
2.9 angle difference: the phase angle difference angle error referred to generally by the symbol δ indicates that it is a 180 ° rotation of the secondary current vector with a phase difference between the current vector. Provides a secondary current vector ahead of the current vector δ is positive, otherwise it is negative, with the points ('

) For the unit.
2.10 thermal stability and dynamic stability factor: power system fault, the current transformer short-circuit currents caused by the huge current role of thermal and electric transformer  current transformers should be able to withstand without damage the ability of this ability to withstand heat

Stability and dynamic stability multiples. Thermal stability factor is the thermal stability current 1s-current transformer heat does not result in exceeding the allowable limit current and the rated current of the current transformer ratio. Dynamic stability factor is the current transformer can withstand the maximum current instantaneous value

Its rated current ratio.