35, 110, 150 kV Oil-immersed current transformers ТФЗМ-П type

The oil-immersed current transformers ТФЗМ-П type are designed for transmission of measurement data signal to measuring, protection, automation, alarm and control instruments in AC 50-60 Hz electric mains.
They are produced for the rated primary current 15 to 2000 A and the secondary current 1 to 5 A. The transformers external insulation is cylindrical or conical, made from electric porcelain. The main internal isolation of the transformers is polymeric. The windings of the transformer are link chain type. The number of secondary windings from two to five, 1-2 of them are measuring windings and 2 to 4 are protection windings. Accuracy class for measuring windings between 0,1 and 0,5; for protection windings - 10P. The safety ratio of the instruments - 10.
Download the questionnaire TFZM.doc [55 Kb] (downloads: 4)

6-10 kV Dry cast current transformers ТОЛ, ТПЛ, ТШЛ type

Current transformers ТОЛ-Э-12, ТПЛ-Э-12, ТШЛ-Э-12 types are designed for AC scale conversion with a view to its further measure and (or) transmission to protection, automation, alarm or control devices in AC 50Hz electric circuits at 6-10 kV voltage class.
The range of rated primary currents 5 - 1000A, rated secondary current 5A, the number of secondary windings - up to 4, rated secondary load with power factor cosφ = 0,8 - 10VA for measuring, 15VA for protection needs.
Accuracy classes for measuring windings - 0,2S - 5P; to protective windings - 5P - 10P.

0,66 kV Null-sequence (residual) current transformers, ТЗЛМ type

The transformers are designed for connection to relay circuits for protection against earth fault of the individual cores of three-phase cable through transformation of the arisen null-sequence (residual) current and may be installed on the cables with diameter up to 70mm - for ТЗЛМ-Э-0,66-01, with diameter up to 100mm - for ТЗЛМ-Э-0,66-02, and with diameter up to 200mm - for ТЗЛМ-Э-0,66-03.

Current transformers

Current transformer is a transformer with primary winding connected to curret source and secondary winding connected to measurement or protective devices with small internal resistance.
Current measurement transformer is a transformer, designed for conversion of a current to a level suitable for measurement. Primary winding of a current transformer have to be connected in series with the measured alternative current, and the gauges are to be connected to the secondary one. The current flowing through the secondary winding of the current transformer, is proportional to the current flowing through its primary one.
Current transformers are widely used for measurement the electric current and as gauges for relay protection devices of electric power systems, thus high accuracy requirements are superimposed on them.
Current transformers provide measurements safety by insulating measurement circuits of high-voltage (up to hungreds of kV) primary circuit.
There are high demands of precision for current transformers. As a rule, the current transformers are performed with two and more groups of secondary windings: one of them usually connected to protection devices, and another one - more precise - for connection a counting and measurement means (for example, electric meters).